Table of contents

It gives us great pleasure to announce that the Siam Physics Congress (SPC2017) held 24-26 May 2017 at the Rayong Marriott Resort and Spa, Thailand was a resounding success, with over 500 participants from throughout Thailand and from other countries. On behalf of the organizers, Kasetsart University and Thai Physics Society, we would like to express our gratitude for the support received from National Astronomical Research Institute of Thailand (NARIT), Synchrotron Light Research Institute (SLRI), Thailand Institute of Nuclear Technology (TINT), Thailand Center of Excellence in Physics (ThEP), National Research Institute of Thailand (NRCT) as well as other corporate sponsors whose generous contributions made this a successful meeting. SPC2017 provided a unique opportunity for experts, academics, and educators to exchange knowledge and build friendships. The meeting consisted of two plenary lectures, invited speaker sessions, and a number of contributed oral and poster presentations. Resulting from the success of SPC2017 are qualified full research articles from the presentations, which have been reviewed and compiled in this IOP Journal of Physics: Conference Series. It is our sincere hope that these proceedings will contribute to advancing our understanding of Physics knowledge and applications and serve as initiators for even greater achievements in the field.

SPC2017 Editorial Team

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

This research was conducted to find out the pattern of the lunar mansions from the position change of the Moon. These positions were called as the lunar mansions. The lunar mansions have 27 groups with important 27 fixed stars. The Moon's position was calculated from nearby stars by cosine formula. The smallest angular separation between the Moon and the fixed stars was the lunar mansion of the day. The graph relates with the date from 2011-2030 and the lunar mansions was showed the lunar mansion's pattern. It was found that the lunar mansion's pattern was a linear equation as M = (0.9882x + 15.4192) ± 0.6910.

Most of the matter in the universe is invisible and is known as dark matter (DM). Weakly Interacting Massive Particles (WIMPs) are possible theoretical candidates for DM. Hypothetically, WIMPs can be detected indirectly by their annihilation or decay products. A possible product is a γ ray. Many DM profile models predict a higher density of WIMPs near the Galactic center. Here we search for monochromatic γ-ray emission from the Galactic center region in data from the Large Area Telescope (LAT), the main instrument onboard the Fermi Gamma-ray Space Telescope. We present the preliminary results of the analysis of γ-ray spectral lines to search for DM annihilation and decay signals using the latest version of the LAT data.

Recurrent novae (RNe) are novae with multiple recorded outbursts powered by a thermonuclear runaway. The outburst occurs on the surface of the white dwarf which accompanies with a late type main-sequence or giant secondary star transferring material onto the white dwarf primary star. They resemble classical novae (CNe) outbursts but only RNe has more than one recorded outbursts. RNe play an important role as one of the suspected progenitor systems of Type Ia supernovae (SNe) which are used as primary distance indicators in cosmology. Thus, it is important to investigate the outburst type of CNe and RNe and finally ascertain the population of objects that might ultimately be candidates for Type Ia SNe explosions. The proposal that RNe occupy a region separated from CNe in an outburst amplitude versus speed class diagram was adopted. Since the low amplitude results from the existence of an evolved secondary and/or high mass transfer rate in the quiescent system, RNe candidates should accordingly have low amplitude. We selected 3 preliminary targets including T Pyx, BT Mon and V574 Pup. Their amplitudes are not that low but the lowest amplitude that can be observed with Thai National Telescope (TNT). We obtained their magnitudes at quiescence using ULTRASPEC camera on the 2.4-m TNT. The positions of three targets on optical and near-infrared color-magnitude diagrams suggest that all three should have main-sequence secondary stars. This is true for T Pyx, whose secondary star has been confirmed its spectroscopy to be a main-sequence star, but not yet confirmed for BT Mon and V574 Pup.

This research aims to study hydrogen alpha emission, corresponding to star formation of galaxies in the NGC 4213 group that has an average recession velocity of 6,821 km/s. The imaging observations with broad-band filters (B, V and RC) and narrow-band filters ([S II] and Red-continuum) were carried out from the 2.4-m reflecting telescope at Thai National Observatory (TNO). There are 11 sample galaxies in this study, consisting of 2 elliptical, 2 lenticular and 7 spiral galaxies. It was found that the late-type galaxies tend to be bluer than early-type galaxies, due to these galaxies consist of relatively high proportion of blue stars. Furthermore, the equivalent width of hydrogen alpha (EW(Hα)) tends to increase as a function of morphological type. This indicates that star formation in late-type galaxies taking place more than the early-type galaxies. Furthermore, a ratio of the star formation rate to galaxy mass also increases slightly with the galaxy type. This could be due to the interaction between galaxy-galaxy or tidal interaction occurring within the galaxy group.

A meteorite is a fragment of pure stone, iron or the mixture of stony–iron. The falling of meteorites into Earth's surface is part of Earth's accretion process from dust and rocks in our solar system. When these fragments come close enough to the Earth to be attracted by its gravity, they may fall into the Earth. Following the detection of objects that fall from the sky onto a home in Phitsanulok in June 27, the meteorites were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS) instruments. The results from SEM/EDS analysis show that the meteorites are mainly composed of Fe-Ni and Fe-s. The meteorite is Achondrite, a class of meteorite which does not contain Chondrule. The meteorites in this work are thought to be part of a large asteroid.

Aurora phenomenon is an effect of collision between precipitating particles with gyromotion along Earth's magnetic field and Earth's ionospheric atoms or molecules. The particles' precipitation occurs normally around polar regions. However, some auroral particles can reach lower latitude regions when they are highly energetic. A clear emission from Earth's aurora is mostly from atomic oxygen. Moreover, the sun's activities can influence the occurrence of the aurora as well. This work studies time variations of oxygen emission lines and solar wind parameters, simultaneously. The emission's spectral lines were observed by Medium Resolution Echelle Spectrograph (MRES) along with 2.4 meters diameter telescope at Thai National Observatory, Intanon Mountain, Chiang Mai, Thailand. Oxygen (OI) emission lines were calibrated by Dech-Fits spectra processing program and Dech95 2D image processing program. The correlations between oxygen emission lines and solar wind dynamics will be analyzed. This result could be an evidence of the aurora in low latitude region.

We present the results of a combined analysis of photometric time series and spectroscopic observations for the semi-detached eclipsing binary AO Ser aimed to study physical parameters of the system. New CCD photometric light curves in the B and V bands and radial velocities of AO Ser are presented. The Wilson-Devinney technique was used to simultaneously analyze the light and radial velocity curves for determining a new set of the system's parameters. The solution shows that AO Ser is a semi-detached eclipsing binary system with a mass ratio of 0.183 ± 0.003, an inclination of 89.42 ± 0.04 degrees and a secondary star's temperature of 4900 K.

The study of orbital elements of Asteroids in Cometary Orbits (ACOs) is based on images taken by a 0.7-m telescope to find positions of asteroids and calculate their orbital elements. This work focuses on variation of positions and orbital shape of an asteroid, 1667Pels, which is obtained by analyzing orbital elements and minimum orbital intersection distances. Each observation, those parameters are affected by the gravity from Jupiter on ACOs. The accuracy of single site data was calibrated by comparing the result from this work to other observations in Minor Planet Center database.

The direct observations of Geostationary Orbit (GEO) satellites above Thailand's sky by 0.7-meters telescope were proceeded at Inthanon Mt., Chiang Mai, Thailand. The observation took place at night with Sidereal Stare Mode (SSM). With this observing mode, the moving object will appear as a streak. The star identification for image calibration is based on (1) a star catalogue, (2) the streak detection of the satellite using the software and (3) the extraction of the celestial coordinate of the satellite as a predicted position. Finally, the orbital elements for GEO satellites were calculated.

NMDC-Palatini cosmology in slow-roll regime is of our interests. We present flat FLRW cosmological NMDC-Palatini field equations and acceleration condition. Late time trajectory is approximated. Chaotic inflation potential is considered here as it is viable in a range of negative coupling constant as constrained by CMB results. Phase portraits show that the NMDC-Palatini gives new saddle-point solutions. The NMDC-Palatini effect decreases the acceleration-allowed region and forbid acceleration at small-field values.

We study a subclass of GLPV modified gravity theories generated by a general disformal metric ${\bar{g}}_{\mu \nu }={g}_{\mu \nu }+D(\phi,\partial \phi ){\partial }_{\mu }\phi {\partial }_{\nu }\phi$. By analyzing the background evolution equation, we have found that such theory cannot provide the self-accelerating solution.

This research studies the nature of auroral feature on Jupiter, especially which connects to one of its satellite, Io. Jupiter has a large magnetosphere, as a result of strong magnetic field strength. This magnetosphere corotates with Jupiter and extends over all of Galilean satellites. The interaction between Jupiter's rotating magnetic field and Io causes plasma particles to flow along the magnetic field lines in directions toward both north and south hemispheres. Some particles will penetrate into Jupiter's ionosphere and collide with atmosphere particles, leading to aurora emission, at the position of Io's auroral footprint. Io is surrounded along its path, by a cloud of plasma particles with high density, which is called Io torus. This torus enhances the effect of bending magnetic field lines when they pass Io and result in inaccuracy of the prediction of longitudinal position of Io footprint. This shift of longitudinal prediction can be mapped to the shifted position of Io, which is called lead angle. Our objective is finding the relation between all three parameters, which are magnetic field strength, Io's footprint brightness and lead angle at the same footprint position or the same Io's longitude. We use VIPAL magnetic field model to trace along the magnetic field line and to find magnetic field strength at any given position. This tool is vital for determination of the relation between magnetic field strength, Io footprint brightness and lead angle.

Jupiter's polar emission has brightness whose behavior appears to be unstable. This work focuses on the bright spot in active region which is a section of Jupiter's polar emission. Images of the aurora were taken by Advanced Camera for Surveys (ACS) onboard the Hubble Space Telescope (HST). Previously, two bright spots, which were found on 13^th May 2007, were suggested to be fixed on locations described by system III longitude. The bright spot's origin in equatorial plane was proposed to be at distance 80-90 Jovian radii and probably associated with the solar wind properties. This study analyzes additional data on May 2007 to study long-term variation of brightness and locations of bright spots. The newly modified magnetosphere-ionosphere mapping based on VIP4 and VIPAL model is used to locate the origin of bright spot in magnetosphere. Furthermore, the Michigan Solar Wind Model or mSWiM is also used to study the variation of solar wind dynamic pressure during the time of bright spot's observation. We found that the bright spots appear in similar locations which correspond to similar origins in magnetosphere. In addition, the solar wind dynamic pressure should probably affect the bright spot's variation.

This research was aimed to study the period variation rate of V1292 Taurus type RR Lyrae variable star. The observational data was obtained on 0.5 meter Reflecting Telescope with CCD photometer camera in (Blue light, B) and (Visible light, V) bands at Regional Observatory for the Public, Nakhon Ratchasima province. The data have been analyzed to plot the light curves. From the (Observed-minus-Calculated, O-C) diagram analysis, we see that the period of this variable star is 0.5714981 ± 0.0001563 days and the period variation rate is increased of 4.8669436 sec/year.

A solar flare is a sudden, rapid, and intense variation in brightness as observed at the Sun. It typically associates with converting magnetic energy to kinetic energy in the form of solar energetic particles (SEPs). The objective of this work is to study the propagation of SEPs from the Sun to the Earth. We simulate the particle propagation for the solar event on August 9, 2011 by using the transport equation from Ruffolo 1995. We solve the transport equation by the numerical technique of finite different method. We find injection duration by fitting the simulation results and the particle data from spacecraft. The X-ray class of the selected solar event is X6.9, the solar flare position on the Sun is N18W68, and the solar wind speed is 551.5 km/s. We found the solar flare on August 9, 2011 is the gradual flare. This flare had the long injection time from the Sun to the Earth corresponding to the shock wave detected after explosion in the interplanetary space 13 minutes. In the path of the solar flare affected on the Earth, the Kp-index (the value of the earth's magnetic field variable) was considered. The Kp-index of these solar flares was less than 3, which they didn't affect on the Earth.

Now the Sun is in the 24^th solar cycle. The peak of solar cycle correspond to the number of the Sun activities, which one of them is solar flare. The solar flare is the violent explosion at the solar atmosphere and releases the high energy ion from the Sun to the interplanetary medium. Solar energetic particles or solar cosmic ray have important effect on the Earth, such as disrupt radio communication. We analyze the particle transport of the solar flare events on August 9, 2011, January 27, 2012, and November 3, 2013 in 24^th solar cycle. The particle data for each solar flare was obtained from SIS instrument on ACE spacecraft. We simulate the particle transport with the equation of Ruffolo 1995, 1998. We solve the transport equation with the numerical technique of finite different. We find the injection duration from the Sun to the Earth by the compared fitting method of piecewise linear function between the simulation results and particle data from spacecraft. The position of these solar flare events are on the west side of the Sun, which are N18W68, N33W85, and S12W16. We found that mean free path is roughly constant for a single event. This implies that the interplanetary scattering is approximately energy independent, but the level of scattering varies with time. The injection duration decreases with increasing energy. We found the resultant variation of the highest energy and lowest energy, because the effect of space environments and the number of the detected data was small. The high mean free path of the high energy particles showed the transport capability of particles along to the variable magnetic field line. The violent explosion of these solar flares didn't affect on the Earth magnetic field with Kp-index less than 3.

Ultraluminous X-ray sources (ULXs) are extra-galaxtic, non-nuclear sources with the X-ray luminosity in excess of the Eddington limit for a 10M_⊙ black hole. Although some ULXs could be candidates for intermediate mass black holes accreting matter at sub-Eddington rate, it is thought that the majority population of ULXs are stellar mass black holes accreting matter at super-Eddington state. In this work, we examine the high quality X-ray spectra of the ULX NGC 1313 X-1 observed by XMM-Newton. The modeling results suggest that the data could be explained well using the super-Eddington model. Moreover, the X-ray spectral evolution of the ULX could be explained successfully in the context of accretion in the super-Eddington state.

The rotation curves of gas-rich dwarf and low surface brightness (LSB) spiral galaxies have provided the most important pieces of evidence for the existence of dark matter. However their shape in the inner regions is one of the outstanding issues in modern cosmology. In order to explain the so-called "cusp-core" problem, we have applied the effect of the gas pressure from dark matter annihilation into electron-positron pairs to the rotation curves of LSB galaxies. The propagation of the electrons and positrons has been determined by the diffusion-loss equation. We have assumed a uniform diffusion coefficient and considered energy loss mechanisms. By fitting rotation curves of LSB galaxies, we are able to find the constraints on dark matter particles.

Synchrotron emission can be a good probe for dark matter particles in the Milky Way. We have investigated the production of electrons and positrons in the Milky Way within the context of dark matter annihilation. Upper limits on the relevant cross-section are obtained by comparing synchrotron emission in the microwave bands with Planck data. According to our results, the dark matter annihilation cross-section into electron-positron pairs should not be higher than the canonical value for a thermal relic if the mass of the dark matter candidate is smaller than a few GeV. In addition, we also look for constraints on the inner slope of dark matter density profile in the Milky Way. Our results indicate that the inner slope of dark matter profile is between 1 to 1.5.

Radial velocity observations for members of the Ori OB1d association in the nebula NGC 1977 were obtained using the MRES spectrograph with the 2.4 m telescope at Thai National Observatory. Radial velocities of 2MASS J05352174-0453118, HD 37059, HD 294264 are detectable for the first time with a value of 30.02, 32.19 and 60.27 km/s, respectively. Combining the obtained radial velocities from this research with database proper motion, it was found that all observed star are moving in a different direction. This might be a result from the fact that Ori OB1d is dynamically young with active ongoing star formation. The association is small and loose. Members are less gravitationally bound and the cluster is expanding.

Pinning phenomena emerge in many dynamical systems. They are found to stabilize extreme conditions such as superconductivity and super fluidity. The dynamics of pinned spiral waves, whose tips trace the boundary of obstacles, also play an important role in the human health. In heart, such pinned waves cause longer tachycardia. In this article, we present two methods for generating pinned spiral waves in a simulated excitable system. In method A, an obstacle is set in the system prior to an ignition of a spiral wave. This method may be suitable only for the case of large obstacles since it often fails when used for small obstacles. In method B, a spiral wave is generated before an obstacle is placed at the spiral tip. With this method, a pinned spiral wave is always obtained, regardless the obstacle size. We demonstrate that after a transient interval the dynamics of the pinned spiral waves generated by the methods A and B are identical. The initiation of pinned spiral waves in both two- and three-dimensional systems is illustrated.

Spiral waves are often found in excitable media. In the hearts, they are abnormal forms of action potential propagation. Under an external forcing, the spiral waves drift and are subsequently terminated at the boundary. Spiral waves can be studied in simulations using a discrete reaction-diffusion system; thereby the time step must not exceed a numerical stability limit (t_s). In this article, we present the dynamics of spiral waves in a simulated system under an external forcing as a modified sinusoidal function of time. The spiral waves are forced to drift along a straight line with a velocity and an angle depending on the time step. An optimization study provides the optimal time step of 0.2t_s, where further reductions of the time step do not alter the drifting of the spiral waves.

Alcohols are solvents for organic and inorganic substances. Dynamic viscosity of liquid is important transport properties. In this study models for estimating n-alkan-1-ol dynamic viscosities are correlated to the Martin's rule of free energy additivity. Data available in literatures are used to validate and support the proposed equations. The dynamic viscosities of n-alkan-1-ol can be easily estimated from its carbon numbers (n_c) and temperatures (T). The bias, average absolute deviation and coefficient of determination (R²) in estimating of n-alkan-1-ol are -0.17%, 1.73% and 0.999, respectively. The dynamic viscosities outside temperature between 288.15 and 363.15 K may be possibly estimated by this model but accuracy may be lower.

Wiangkalong is one of major ceramic production cities in northern of Thailand, once colonized by the ancient Lanna Kingdom (1290 A.D.). Ancient Wiangkalong potteries were produced with shapes and designs as similar as those of the Chinese Yuan and Ming Dynasties. Due to the complex nature of materials and objects, extremely sensitive, spatially resolved, multi-elemental and versatile analytical instruments using non-destructive and non-sampling methods to analyze theirs composition are need. In this work, micro-beam X-ray fluorescence spectroscopy based on synchrotron radiation was firstly used to characterize the elemental composition of the ancient Wiangkalong pottery. The results showed the variations in elemental composition of the body matrix, the glaze and the underglaze painting, such as K, Ca, Ti, V, Cr, Mn and Fe.

Transverse emittance of a charged particle beam is one of the most important properties that reveals the quality of the beam. It is related to charge density, transvers size and angular displacement of the beam in transverse phase space. There are several techniques to measure the transverse emittance value. One of practical methods is the pepper-pot technique, which can measure both horizontal and vertical emittance value in a single measurement. This research concentrates on development of a pepper-pot device to measure the transverse emittance of electron beam produced from an accelerator injector system, which consists of a thermionic cathode RF electron gun and an alpha magnet, at the Plasma and Beam Physics Research Facility, Chiang Mai University. Simulation of beam dynamics was conducted with programs PARMELA, ELEGANT and self-developed codes using C and MATLAB. The geometry, dimensions and location of the pepper-pot as well as its corresponding screen station position were included in the simulation. The result from this study will be used to design and develop a practical pepper-pot experimental station.

Photocathode radio-frequency (RF) electron guns are widely used at many particle accelerator laboratories due to high quality of produced electron beams. By using a short-pulse laser to induce the photoemission process, the electrons are emitted with low energy spread. Moreover, the photocathode RF guns are not suffered from the electron back bombardment effect, which can cause the limited electron current and accelerated energy. In this research, we aim to develop the photocathode RF gun for the linac-based THz radiation source. Its design is based on the existing gun at the PBP-CMU Linac Laboratory. The gun consists of a one and a half cell S-band standing-wave RF cavities with a maximum electric field of about 60 MV/m at the centre of the full cell. We study the beam dynamics of electrons traveling through the electromagnetic field inside the RF gun by using the particle tracking program ASTRA. The laser properties i.e. transverse size and injecting phase are optimized to obtain low transverse emittance. In addition, the solenoid magnet is applied for beam focusing and emittance compensation. The proper solenoid magnetic field is then investigated to find the optimum value for proper emittance conservation condition.

Pinned spiral waves are exhibited in many excitable media. In cardiology, lengthened tachycardia correspond to propagating action potential in forms of spiral waves pinned to anatomical obstacles including veins and scares. Thus, elimination such waves is important particularly in medical treatments. We present study of unpinning of a spiral wave by a wave train initiated by periodic stimuli at a given location. The spiral wave is forced to leave the rectangular obstacle when the period of the wave train is shorter than a threshold T_unpin. For small obstacles, T_unpin decreases when the obstacle size is increased. Furthermore, T_unpin depends on the obstacle orientation with respect to the wave train propagation. For large obstacles, T_unpin is independent to the obstacle size. It implies that the orientation of the obstacle plays an important role in the unpinning of the spiral wave, especially for small rectangular obstacles.

Electrocardiogram (ECG) is a crucial tool in the detection of cardiac arrhythmia. It is also often used in a routine physical exam, especially, for elderly people. This graphical representation of electrical activity of heart is obtained by a measurement of voltage at the skin; therefore, the signal is always contaminated by noise from various sources. For a proper interpretation, the quality of the ECG should be improved by a noise reduction. In this article, we present a study of a noise filtration in the ECG by using an empirical wavelet transform (EWT). Unlike the traditional wavelet method, EWT is adaptive since the frequency spectrum of the ECG is taken into account in the construction of the wavelet basis. We show that the signal-to-noise ratio increases after the noise filtration for different noise artefacts.

In this work, hydroxyapatite (HA) and hydroxyapatite doped with Sr (HA-Sr), Zn (HA-Zn) and both Sr-Zn (HA-SrZn) were synthesized by a sol-gel method and combined with polycaprolactone (PCL) to make HA/PCL composites using an electrospinning technique. The synthesized nanoparticles and their composite fibers were investigated using various techniques. The X-Ray Diffraction (XRD) result showed the characteristic peaks of the hydroxyapatite structure; whereas the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results revealed that the synthesized nanoparticles were successfully incorporated into the randomly interconnected and highly porous PCL matrix.

Gallium nitride doped with a small concentration of manganese (Ga_1−xMn_xN) is one of diluted magnetic semiconductors which can be used for spintronic applications. In this work, Ga₃₁Mn₁N₃₂ in the zinc blende (ZB) and rock salt (RS) structures were investigated. We employed the density functional theory (DFT) within the generalized gradient approximation (GGA) to study structural properties, the density of states and the magnetization. The structural phase transitions under pressure up to 60 GPa were also studied. We found that Ga₃₁Mn₁N₃₂ in the ZB phase is stable at ambient pressure, and change to the RS phase at about 42 GPa. By using GGA+U, the absolute magnetization is 4.68 μ_B per cell at 0 GPa. We found also that the absolute magnetization is reduced under pressure.

MgSiN₂ semiconductor is alternative material beyond the family of III-N, which is used widely in optoelectronic devices. This work presents the calculations of the dielectric tensor, Born effective charge tensor, phonon frequencies at Γ point, phonon dispersion, Helmholtz free energy (ΔF), internal energy (ΔE), entropy (ΔS) and specific heat capacity at constant volume (C_v) of MgSiN₂ by using the density-functional perturbation theory (DFPT) as implemented in ABINIT. We found that the phonons and thermal properties of MgSiN₂ have similar properties to those of ZnSiN₂ and C_v of MgSiN₂ are in agreement with the available experimental results.

We proposed a method to calculate the effective capacitance of a metallic single-electron transistor using the quantum Monte Carlo method to describe the Coulomb blockade effect. The effective capacitance depended on the induced gate charge, temperature, and conductance of the system. Furthermore, the results can be used to calculate the effective charging energy, which has been characterizing the strength of the Coulomb blockade effect. In the Coulomb blockade regime, the effective charging energy was approximately equal to charging energy. In particularly, the effective charging energy decreased with an increase in the conductance and temperature.

Mismatch effect of renormalized Fermi velocity of massive Dirac fermions on the spin transport properties and tunneling magnetoresistance in a gapped graphene-based ferromagnetic/velocity barrier/ferromagnetic (FG/VB/FG') junction is investigated. The electrostatic potential created by the applied voltage on the VB region can generate spin-dependent collimation of Dirac fermions. The quantum beating pattern in the spin conductance oscillation are shown as a function of the Fermi energy at low velocity ratio (the Fermi velocity inside the barrier to that outside the barrier). The Fermi-velocity mismatch effect between graphene junction give rises to the oscillating behavior of negative tunneling magnetoresistance at the velocity ratio less than one.

We study the Josephson effect in a gapped graphene-based superconductor/barrier/superconductor junction using the Dirac-Bogoliubov de Gennes (DBdG) equation for theoretical prediction. A massive gap of this regime is induced by fabricating a monolayer graphene on substrate-induced bandgap and superconductivity is acquired by the proximity effect of conventional superconductor (s-wave superconductor) through top gate electrodes. This Josephson junction is investigated in case of thick barrier limit that is pointed out the effect of applying a gate voltage V_G in the barrier. We find that the switching supercurrent can be controlled by the gate V_G and the effect of thick barrier can influence the switching linear curve. When the barrier is adjusted to manner of a potential well which is inside the range of $-m{v}_{F}^{2}\le {V}_{G}\le 0$, the supercurrent in the thick barrier case is examined to the same behavior as the thin barrier case. The controlling supercurrent through the electrostatic gate is suitable for alternative mechanism into experimental test.

Puffing technique is the process that can improve texture and volumetric of crisp fruit and vegetable. However, the effect of chemical composite in foods on puffing characteristics is still lack of study. Therefore, potato and apple slices were comparative study on their physical properties. Potato and apple were sliced into 2.5 mm thickness and 2.5 cm in diameter. Potato slices were treated by hot water for 2 min while apple slices were not treatment. After that, they were dried in 3 steps. First step, they were dried by hot air at temperature of 90°C until their moisture content reached to 30, 40, and 50 % dry basis. Then they were puffed by hot air at temperature of 130, 150, and 170°C for 2 min. Finally, they were dried again by hot air at temperature of 90°C until their final moisture content reached to 4% dry basis. The experimental results showed that chemical composite of food affected on physical properties of puffed product. Puffed potato had higher volume ratio than those puffed apple because potato slices contains starch. The higher starch content provided more hard texture of potato than those apples. Puffing temperature and moisture content strongly affected on the color, volume ratio, and textural properties of puffed potato slices. In addition, the high drying rate of puffed product observed at high puffing temperature and higher moisture content.

Today, dried shrimp in the market were refused food colour and drying until shrimp are colourful and tasty. Meanwhile, Community groups, women's health trying to produce food products come from herbs. As an alternative to consumers. The production process is also a traditional way to dry. In order to extend the shelf life longer. Sometimes, potential risks, both in quality and quantity of products. As a result, consumers are enormous. Thus, this research aims to study the possibility to produce shrimp dried mixed with turmeric and salt. Then dried shrimp mixed with turmeric and salt to keep up the quality criteria of the Food and Drug Administration-FDA It can reduce the risk of the consumer and can keep up in a kitchen Thailand. When buying shrimp from the fisherman's boat Will be made clear, clean impurities and shaking the sand to dry. Prepare a mixture of turmeric and salt. The shrimp were dipped into a beef with stirrer for 3 minutes. And scoop up centrifugal shrimp with dried. Measurement of initial moisture content averaging 78%wb. Then drying technique Spouted enter the rectangular chamber a continuous manner. Until average moisture content to 17%wb. The air temperature in the drying chamber at 180 °C and hot air speed 4.5 m/s, a state heat transfer Mass and moisture within the shrimp. In chamber when drying, the shrimp have moved freely behaviour can spit water out faster does not burn. Shaving legs of shrimp shell fragments lightweight is sorting out the top of drying chamber. Private shrimp were dried out to the front of the quad drying chamber. Power consumption 27.5 MJ/kg, divided into electrical energy 12.3 MJ/kg and thermal energy is 15.2 MJ/kg. The hot air comes from burning LPG gas burner with dual automatic. And can adjustable to room temperature drying characteristics modulation setting.

The Weather Research and Forecasting (WRF v. 3.7) model was applied to model PM10 data in Chiang Mai city for 10-days during a high haze event utilizing updated land use categories from the Moderate Resolution Imaging Spectroradiometer (MODIS). A higher resolution meteorological lateral boundary condition (from 1 degree to 0.25 degree) was also used from the NCEP GDAS/FNL Global Tropospheric Analyses and Forecast Grid system. A 3-category urban canopy model was also added and the Thompson aerosol-aware microphysics parameterization scheme was used to model the aerosol number concentrations that were later converted to PM10 concentrations. Aerosol number concentration monthly climatology was firstly used as initial and lateral boundary conditions to model PM10 concentrations. These were compared to surface data obtained from two stations of the Pollution Control Department (PCD) of Thailand. The results from the modeled PM10 concentrations could not capture the variability (r = 0.29; 0.27 for each site) and underestimated a high PM10 spike during the period studied. The authors then added satellite data to the aerosol climatology that improved the comparison with observations (r = 0.45; 43). However, both model runs still were not able to capture the high PM10 concentration event. This requires further investigation.

Bangkok is located on the soft marine clay in the Lower Chao Phraya Basin which can amplify seismic wave and can affect the shaking of buildings during an earthquake. Deep shear wave velocity of the sediment in the basin are useful for study the effect of the soft sediment on the seismic wave and can be used for earthquake engineering design and ground shaking estimation, especially for a deep basin. This study aims to measure deep shear wave velocity and create 2D shear wave velocity profile down to a bedrock in the southern Bangkok by the Microtremor measurements with 2 seismographs using Spatial Autocorrelation (2-SPAC) technique. The data was collected during a day time on linear array geometry with offsets varying between 5-2,000 m. Low frequency of natural tremor (0.2-0.6 Hz) was detected at many sites, however, very deep shear wave data at many sites are ambiguous due to man-made vibration noises in the city. The results show that shear wave velocity of the sediment in the southern Bangkok is between 100-2,000 ms^-1 and indicate that the bedrock depth is about 600-800 m, except at Bang Krachao where bedrock depth is unclear.

In this study, comparisons of spectral ultraviolet irradiance at 305, 310, 324 and 380 nm at the overpass time retrieved from OMI/AURA satellite with that from ground-based measurements were performed at Nakhon Pathom (13.82°N,100.04°E), Thailand. The analyzed data period comprised from 1 January 2010 to 31 December 2015. The comparison results clearly showed the overestimation of satellite data with root mean square difference (RMSD) between 22.9 and 48.9%, and mean bias difference (MBD) between 5.3 and 39.8% for all sky conditions, and reduced to 10.6-40.5% and 0.18-34.9% for clear sky conditions. Further results showed that the differences between the two datasets depend on atmospheric aerosol loads and clouds.

Clouds play very important role in the variation of surface solar radiation and rain formation. To understand this role, it is necessary to know the physical and geometrical of properties of cloud. However, clouds vary with location and time, which lead to a difficulty to obtain their properties. In this work, a ceilometer was installed at a station of the Royal Rainmaking and Agricultural Aviation Department in Chiang Mai (17.80° N, 98.43° E) in order to measure cloud base height. The cloud base height data from this instrument were compared with those obtained from LiDAR, a more sophisticated instrument installed at the same site. It was found that the cloud base height from both instruments was in reasonable agreement, with root mean square difference (RMSD) and mean bias difference (MBD) of 19.21% and 1.58%, respectively. Afterward, a six-month period (August, 2016-January, 2017) of data from the ceilometer was analyzed. The results show that mean cloud base height during this period is 1.5 km, meaning that most clouds are in the category of low-level cloud.

Instant food is a product produced for convenience for consumer. Qualities are an important attribute of food materials reflecting consumer acceptance. The most problem of instant rice is casehardening during drying process resulted in the longer rehydration time. The objective of this research was to study the qualities of shredded Thai-style instant rice under a combined gas-fired infrared and air convection drying. Additionally, the mathematical models for gas-fired infrared assisted thin-layer drying of shredded Thai-style rice for traditional was investigated. The thin-layer drying of shredded Thai-style rice was carried out under gas-fired infrared intensities of 1000W/m², air temperatures of 70°C and air velocities of 1 m/s. The drying occurred in the falling rate of drying period. The Page model was found to satisfactorily describe the drying behavior of shredded Thai-style rice, providing the highest R² (0.997) and the lowest MBE and RMSE (0.01 and 0.18) respectively. A 9 point hedonic test showed in softness and color, but odor and overall acceptance were very similar.

The objective of this research was to produce green fuel briquettes from corncobs by adding macadamia shell charcoal powder. The study was sectioned into 3 parts: 1) Quality improvement of green fuel briquettes by adding macadamia; 2) Fuel property analysis based on ASTM standards and thermal fuel efficiency; and 3) Economics appropriateness in producing green fuel briquettes. This research produced green fuel briquettes using the ratio of corncobs weight and macadamia shell charcoal powder in 100:0 90:10 80:20 70:30 60:40 and 50:50 and pressing in the cold briquette machine. Fuel property analysis showed that green fuel briquettes at the ratio 50:50 produced maximum heating values at 21.06 Megajoule per kilogram and briquette density of 725.18 kilograms per cubic meter, but the percent of moisture content, volatile matter, ash, and fixed carbon were 10.09, 83.02, 2.17 and 4.72 respectively. The thermal efficiency of green fuel briquettes averaged 20.22%. Economics appropriateness was most effective where the ratio of corncobs weight to macadamia shell charcoal powder was at 50:50 which accounted for the cost per kilogram at 5.75 Baht. The net present value was at 1,791.25 Baht. Internal rate of return was at 8.62 and durations for a payback period of investment was at 1.9 years which was suitable for investment.

In this research we investigate the relationships between wind speed and temperature time series data in Bangkok, Thailand, from the time interval of January 2009 to December 2011 using wavelet transform (WT), cross wavelet transform (XWT) and wavelet coherence (WTC). The results from all three wavelet analysis show the strong periodicity around period 1 day (hourly data) and period band 256-450 days (daily data) variations that are exhibited in both wind speed and temperature data across the entire power spectrum from 2009 to 2011. These two oscillations are connected with the natural day time effects and the annual natural season cycle. Although the daily periodic for the temperature is appeared nearly uniform all year but it is not the case for wind speed. In 2009 this wind speed oscillations appear only from mid-February to mid-April in summer and from the fourth week of May to the third week of August in rainy season. XWT also detects strong high common power between the wind speed and temperature at a period band of 14-25 days in summer 2009, a period band of 4-8 days in summer 2009, July 2009, summer 2010 and summer 2011. WTC shows the coherence period band around 10-30 days appeared in summer and rainy season and 32-50 days in summer 2009 and rainy season in 2010. From these three wavelet analysis, the wind speed and temperature time series data show the strong correlation especially at 1 day and 256-450 days period band and also at several different scales. This studied will be helpful in predicting the wind speed and temperature for the future used.

The purpose of this research is to study the thermal efficiency of natural convection. The working principle of natural convection solar dryer is, once the air in the solar dryer is heated by solar energy, the air relative humidity will drop and floating up through the drying. This air will take moisture out of the product and flow out to the ambient air. It was found from the experiment that, in the duration of 8.00 am – 4.00 pm on a clear sky day, an all-day average ambient air and inside the chamber temperature were 38.34°C and 63.19°C respectively. At the solar radiation intensity of 759.53W/m2, mass flow rate of air was 0.023 kg/s and the thermal efficiency of the solar dryer was 2.59%.

In present day, rainfall estimation by weather radar is widely used. Meteorologists use various z-r relationships to appropriate rainfall estimation for different study areas which have different factors such as topography, climate, rain pattern, types of clouds, etc. This research aims to determine the appropriate altitude of radar reflectivity (Z-Level) to provide accurate rainfall estimation. This research will use radar reflectivity data (Z) from Omkoi radar station, which is owned by the Department of Royal Rainmaking and Agricultural Aviation (DRRAA). It uses radar reflectivity data from 1.5 to 13.5 kilometers above mean sea level. We convert it to daily rainfall from radar (R) using Omkoi Z-R relationship (Z=92.4R^1.5) and compare the result to daily rainfall measured by rain gauge stations (G) from 82 rain gauge stations of Thai Meteorological Department (TMD), covering areas within radius of Omkoi radar station (180 km) in the northern of Thailand. The study will consider comparing various statistics of rainfall from radar (R) and rainfall from rain gauges (G), such as correlation coefficients, root mean square error (RMSE) and the characteristic distribution of graphs (Scatter Plot). The results show that the radar reflectivity data in altitude 3.5 km above mean sea level are the most suitable to be used to determine the Z-R Relationship. Therefore, determination of Z-R relationship of Omkoi radar station should be based on the radar reflectivity data at altitude 3.5 km above mean sea level.

We report the differences in light stable isotopes between two kinds of Thai rice (Thai jasmine and Sungyod rice). Thai jasmine rice and Sungyod rice were cultivated in the northeast and the south of Thailand. Light isotopes including 13C, 15N and 18O of Thai jasmine rice and Sungyod rice samples were carried out using isotope ratio mass spectrometry (IRMS). Thai jasmine rice (Khao Dawk Mali 105) was cultivated from Thung Kula Rong Hai area, whereas Sungyod rice was cultivated from Phathalung province. Hypothesis testing of difference of each isotope between Thai jasmine rice and Sungyod rice was also studied. The study was the feasibility test whether the light stable isotopes can be the variables to identify Thai jasmine rice and Sungyod rice. The result shows that there was difference in the isotope patterns of Thai jasmine rice and Sungyod rice. Our results may provide the useful information in term of stable isotope profiles of Thai rice.

This study aims to investigate the elemental compositions in 93 Thai rice samples using instrumental neutron activation analysis (INAA) and to identify rice according to their types and rice cultivars using statistical analysis. As, Mg, Cl, Al, Br, Mn, K, Rb and Zn in Thai jasmine rice and Sung Yod rice samples were successfully determined by INAA. The accuracy and precision of the INAA method were verified by SRM 1568a Rice Flour. All elements were found to be in a good agreement with the certified values. The precisions in term of %RSD were lower than 7%. The LODs were obtained in range of 0.01 to 29 mg kg^-1. The concentration of 9 elements distributed in Thai rice samples was evaluated and used as chemical indicators to identify the type of rice samples. The result found that Mg, Cl, As, Br, Mn, K, Rb, and Zn concentrations in Thai jasmine rice samples are significantly different but there was no evidence that Al is significantly different from concentration in Sung Yod rice samples at 95% confidence interval. Our results may provide preliminary information for discrimination of rice samples and may be useful database of Thai rice.

This research studied about electricity cogenerator from Hydrogen and Biogas and the factors that cause that effecting Hydrogen from Aluminium which was a cylindrical feature. By using a catalyst was NaOH and CaO, it was reacted in distilled water with percentage of Aluminium: the catalyst (NaOH and CaO) and brought to mix with Biogas afterwards, that have been led to electricity from generator 1 kilowatt. The research outcomes were concentration of solutions that caused amount and percent of maximum Hydrogen was to at 10 % wt and 64.73 % which rate of flowing of constant gas 0.56 litter/minute as temperature 97 degree Celsius. After that led Hydrogen was mixed by Biogas next, conducted to electricity from generator and levelled the voltage of generator at 220 Volt. There after the measure of electricity current and found electricity charge would be constant at 3.1 Ampere. And rate of Biogas flowing and Hydrogen, the result was the generator used Biogas rate of flowing was highest 9 litter/minute and the lowest 7.5 litter/minute, which had rate of flowing around 8.2 litter/minute. Total Biogas was used around 493.2 litter or about 0.493 m³ and Hydrogen had rate of flowing was highest 2.5 litter/minute.

Biogas produced from the fermentation in the province of Maha Sarakham of excreta from cow dung, fattening pigs and buffalo dung in small scale farms contained hydrogen sulfide (H₂S) at 764, 926 and 1,103 ppm, respectively. This gas has offensive smell and is corrosive to motor and metal stove of farmers, thus needs to be eliminated. The adsorbent granules soaking in FeCl₃ and NaOH made from grey cement mixed with diatomaceous earth or fine sand. The experiment cow dung, fattening pigs and buffalo dung farms revealed that the adsorbent granules made from fine sand mixed with grey cement had better efficiency in reducing H₂S than diatomaceous earth plus grey cement or scrap iron (97.1-91.4 vs. 86.0-64.3 and 77.9-89.4%, P<0.01). The reduction of H₂S increased with the increasing weight of the adsorbent tanks, made from fine sand mixed with grey cement, from 2 to 4 and 6 kg (84.1-89.2 to 92.7-98.0 and 100-99.1%, respectively). Adsorbent set of 6 kg weight can be reduced H₂S in biogas from 3,141 to 0 ppm in the first day and to 6 ppm on day 25 of using period, during which the colour of adsorbent granules changed from red brown to dark brown.

In this study, Potential increasing of rubber sheet production with fungus displacement by solar tunnel dryer. By integrating a biomass gasifier as an assisting heat source for drying Rubber Sheet produce and its performance analysis has been investigated. An experimental study has been carried out with the stand-alone solar tunnel dryer and the dryer with the assisted biomass gasifier. For thermal performance analysis, for wind speed 1.0 m/s, the dryer with assisted gasifier gave an average efficiency of 32.86% higher and the drying period was 31.45 % shorter than those of the unit without the gasifier. For wind speed 1.5 m/s, and for wind speed 2.0 m/s, the values are 21.49 %, 28.68 % and 33.17%, 24.54 %, respectively. From the economic analysis, drying of wind speed 1.5 m/s is the most appropriated. The payback and the IRR were 1.8 years and 55.48 %, respectively. While those for wind speed 1.0 m/s were 2.74 years and 36%, respectively.

Atmospheric water vapor is a crucial component of the Earth's atmosphere, which is shown by precipitable water vapor. It is calculated from the upper air data. In Thailand, the data were collected from four measuring stations located in Chiang Mai, Ubon Ratchathani, Bangkok, and Songkhla during the years 1998-2013. The precipitable water vapor obtained from this investigation were used to define an empirical model associated with the vapor pressure, which is a surface data at the same stations. The result shows that the relationship has a relatively high level of reliability. The precipitable water vapor obtained from the upper air data is nearly equal to the value from the model. The model was used to calculate the precipitable water vapor from the surface data 85 stations across the country. The result shows that seasonal change of the precipitable water vapor was low in the dry season (November-April) and high in the rainy season (May-October). In addition, precipitable water vapor varies along the latitudes of the stations. The high value obtains for low latitudes, but it is low for high latitudes.

Supersymmetry (SUSY) is one of the most active fields of research in high-energy physics and particle physics. However, SUSY is not so easily accessible for students wishing to get started on this field of research due to complexities often associated with quantum field theories. In this article, I'll discuss some aspects of SUSY in the context of quantum mechanics. In particular, I'll demonstrate how to supersymmetrize a familiar quantum system in the case of a square well and a harmonic oscillator. The harmonic oscillator clearly demonstrate the hallmark of SUSY which link a bosonic degree of freedom and a fermionic degree of freedom. I'll briefly discuss the applications of SUSY in particle physics.

Neutron monitors (NMs) are ground-based detectors designed to measure the cosmic ray (CR) intensity by measuring secondary particles. A Forbush decrease (FD) is a sudden decrease in the CR-intensity count rate and the amplitude of the decreases changes with the different cutoff rigidity of each NM station. The Princess Sirindhorn NM (PSNM) was established in 2007, an NM64-type and 3 bare tubes located at the world's highest geomagnetic vertical cutoff rigidity 16.8 GV was installed at Doi Inthanon in Thailand, 2565 m above sea level. In this work, we study the FDs in CR intensity detected at PSNM that occurred during the 5 years of 2010-2015 in the 24^th solar cycle. We analyse the FDs at the Oulu NM in Finland in order to identify and compare them. We identify 46 FDs at both PSNM and Oulu NMs then we used the student's t-test to assess difference in the mean between simultaneous or non-simultaneous of FDs event. We found that the 46 FDs, 22 are simultaneous and 24 non-simultaneous. Furthermore, we also found that student's t-test analysis reveals that FDs at PSNM have smaller intensity variation of main phase duration of main phase than at Oulu NM. The results of the present statistical analysis that support the PSNM can provide CR data of reliability comparable to that of the Oulu NM. This work also provides unique data of FDs and solar modulation.

The diameter measurement of sphere is very important in dimensional metrology. The measurement of diameter is generally carried out by a comparison method or direct method using 1D linear measuring system. The probes touch both sides of the workpiece and the diameter is determined from displacement of the probes. The contact force is generally operated at 1N which yield deformation due to force of approximately 1 μm with uncertainty of ±0.2 μm. This system provides good performance but has a limitation when workpiece is made from soft matter or sensitive to scratch. National Institute of Metrology (Thailand) developed a laser interferometer system which is equipped with reference spherical lens in order to make non-contact radius measurement of spherical objects possible. Radius of completed sphere and partial sphere with radius range from 1 mm up to 50 mm can be measured with accuracy of ±2.4 μm.

The local gravity measurement using relative gravimeter was confirmed to the reference absolute gravity station by National Institute of Metrology (Thailand); NIMT. Five known absolute gravity value stations were used in this confirmation. By applying the A-B-A measurement pattern, the time dependent of the relative gravity value at the reference station was calculated. Then the short term drift correction was introduce to the relative gravity reading of the loop. The relative gravity difference (Δg_rel) was compared to the absolute gravity difference (Δg_abs) between A-B stations. Five measurement loops were given the maximum difference between Δg_rel and Δg_abs of 0.012 mGal which is less than the absolute gravity uncertainty value of the station in that measurement loop. Therefore, the relative gravimeter is confirmed to report the local gravity value rely on the reference absolute gravity station using daily measurement loop with A-B-A pattern.

This work was aimed to design and construction of portable survey meter for radiation dose measuring. The designed system consists of 4 main parts consisting of low voltage power supply, radiation detection, radiation measurement and data display part on android phone. The test results show that the ripple voltage of low voltage power supply is less than 1%, the maximum integral counts are found to be 10⁴ counts per second and the maximum distance of wireless commination between the server and the client is about 10 meter. It was found that the developed system had small size and light weight for portable instrument.

The LVDT probe is a very important component used in gauge blocks calibration via a mechanical comparative method. The probe is used to determine the central length difference between a reference gauge block and gauge block under-tested (UTC). Typically, an UTC and a reference gauge block have the same nominal length. However, some gauge blocks UTC are specially made for specific purpose where the reference gauge blocks with the same nominal length are not commercially available. Various reference gauge blocks are wrung in order to provide nominal length the same as that of the UTC. Wringing process is the troublesome step and causes larger measurement uncertainty. The lower accuracy is higher number of gauge block used to create reference gauge block, in order to improve accuracy of measurement, the LVDT probe was used at the longer range where the reference gauge block and the UTC don't need to be the same nominal length. In this paper, characteristics of LVDT probe was investigated as it is related to the accuracy of the measurement result. Errors of LVDT probe came from non-linearity, calibration factor, retrace error, repeatability and maximum difference in length. A pair of gauge block, calculated by the Twyman-Green interferometer, length different range 5 μm to 230 μm was used in the study. Non-linearity of LVDT is evaluated by a simple linear regression model. The non-linearity of LVDT probe, calibration factor, retrace error, repeatability and maximum difference in length are 25 nm, 1.0003, 3 nm, 6 nm and 80 nm, respectively. Therefore, by using this technique, central length difference between the 2 gauge blocks up to 80 nm can be calibrated with the uncertainty due to non-linearity of 15 nm The experiment shows the large error of retrace closes to 0.02 μm at 0.09 μm. This can be determined the maximum difference in length to calibrate gauge blocks at difference nominal lengths. The measurement uncertainty of non-linearity is evaluated and it is close to 15 nm.

Precise surface roughness measurement is crucial as it has a direct effect on surface quality. In this work, Proficiency Testing (PT), which is an important process for conformity assessment, was conducted based on a portable roughness tester as a standard measuring instrument. There were seven calibration laboratories from Thailand that participated in the PT with a technical protocol that was designed by NIMT. The roughness tester was provided by NIMT. Two roughness standards with different roughness values (Ra ≤1 and Ra >1) were prepared by each calibration laboratory. The PT measurands were common roughness parameters such as Ra and Rsm. As the roughness measuring instrument is based on LVDTs, we propose here a new proficiency testing evaluation which involves the calibration of the measuring instrument in the PT evaluation procedure. The PT results, according to ISO/IEC 17043, shows that six out of the seven participating laboratories indicated satisfactory performance (|En| ≤ 1) where the measurement uncertainty was based on a 95% confidence level. The PT results and evaluation procedure for conformity assessment of the roughness measuring instrument are presented. Finally, measurement techniques to improve measurement quality are recommended.

The temperature control system was designed and built for application in dielectric spectroscopy. It is based on the dual-stage Peltier element that decreases electrical power and no cryogenic fluids are required. A proportional integral derivative controller was used to keep the temperature stability of the system. A Pt100 temperature sensor was used to measure temperature of the sample mounting stage. Effect of vacuum isolation and water-cooling on accuracy and stability of the system were also studied. With the incorporation of vacuum isolation and water-cooling at 18 °C, the temperature of the sample under test can be controlled in the range of -40 °C to 150 °C with temperature stability ± 0.025 °C.

The penetrated depth of the Rockwell hardness testing machine is normally not more than 0.260 mm. Using commercial load cell cannot achieve the proposed force calibration according to ISO 6508-2[1]. For these reason, the high stiffness load cell (HSL) was fabricated. Its obvious advantage is deformation less than 0.020 mm at 150 kgf maximum load applied. The HSL prototype was designed in concept of direct compression and then confirmed with finite element analysis, FEA. The results showed that the maximum deformation was lower than 0.012 mm at capacity.

The purpose of this research is designed and constructed of a small vacuum furnace. A cylindrical graphite was chosen as the material of the furnace, the cylinder aluminium and copper sheets were employed to prevent the heat radiation that transfers from the furnace to the chamber wall. A rotary pump used, the pressure of graphite furnace can be pumped up to 30 mTorr and heated up to 700 °C driving by wire and the temperature of the chamber wall is relatively remained too low. In addition, heat loss obtained from the graphite furnace by conduction, convection, and radiation were analyzed. The dominating heat loss was found to be caused by the blackbody radiation, which can thus be used to estimate the relationship between graphite furnace temperature and the drive power needed. The cylindrical graphite furnace has an inner diameter of 44 mm, the outer diameter of 60 mm and 45 mm in height, the 355.5 W of power is needed to drive the furnace to 700 °C.

Radio astronomical observations have increasingly been threaten by the march of today telecommunication and wireless technology. Performance of radio telescopes lies within the fact that astronomical sources are extremely weak. National Astronomy Research Institute of Thailand (NARIT) has initiated a 5-year project, known as the Radio Astronomy Network and Geodesy for Development (RANGD), which includes the establishment of 40-meter and 13-meter radio telescopes. Possible locations have been narrowed down to three candidates, situated in the Northern part of Thailand, where the atmosphere is sufficiently dry and suitable for 22 and 43 GHz observations. The Radio Frequency Interference (RFI) measurements were carried out with a DC spectrum analyzer and directional antennas at 1.5 meter above ground, from 20 MHz to 6 GHz with full azimuth coverage. The data from a 3-minute pointing were recorded for both horizontal and vertical polarizations, in maxhold and average modes. The results, for which we used to make preliminary site selection, show signals from typical broadcast and telecommunication services and aeronautics applications. The signal intensity varies accordingly to the presence of nearby population and topography of the region.

We present a portable device for long-time recording of the temperature at multiple measuring points. Thermocouple wires are utilized as the sensors attached to the objects. To minimize the production cost, the measured voltage signals are relayed via a multiplexer to a set of amplifiers and finally to a single microcontroller. The observed temperature and the corresponding date and time, obtained from a real-time clock circuit, are recorded in a memory card for further analysis. The device is powered by a rechargeable battery and placed in a rainproof container, thus it can operate under outdoor conditions. A demonstration of the device usage in a mandarin orange cultivation field of the Royal project, located in the northern Thailand, is illustrated.

We developed a measurement system for collecting and analyzing the fringe pattern images from a gauge block interferometer. The system was based on Raspberry Pi which is an open source system with python programming and opencv image manipulation library. The images were recorded by the Raspberry Pi camera with five-megapixel capacity. The noise of images was suppressed for the best result in analyses. The low noise images were processed to find the edge of fringe patterns using the contour technique for the phase shift analyses. We tested our system with the phase shift patterns between a gauge block and a reference plate. The phase shift patterns were measured by a Twyman-Green type of interferometer using the He-Ne laser with the temperature controlled at 20.0 °C. The results of the measurement will be presented and discussed.

The purpose of this paper is to develop a digital lock-in amplifier based on soundcard interface for undergraduate physics laboratory. Both series and parallel RLC circuit laboratory are tested because of its well-known, easy to understand and simple confirm. The sinusoidal signal at the frequency of 10 Hz – 15 kHz is generated to the circuits. The amplitude and phase of the voltage drop across the resistor, R are measured in 10 step decade. The signals from soundcard interface and lock-in amplifier are compared. The results give a good correlation. It indicates that the design digital lock-in amplifier is promising for undergraduate physic laboratory.

In this research, a non-destructive, simple and rapid method, photothermal deflection technique or the so-called "mirage effect", is setup. A flat and smooth sample is heated by a modulated 532 nm 14 mW pump beam on the surface. The heat flow induced by the surface layer is detected by the 632 nm 0.14 mW probe beam. The frequency-dependent signal in the range of 1 - 800 Hz is measured by lock-in amplifier in term of amplitude and phase. The clay roof tile with and without the waterproof glaze layer on top are the measured samples. The results give the thermal diffusivities of the clay roof tile and the waterproof glaze layer of 0.67 mm²s^-1 and 2.32 mm²s^-1, respectively.

A non-destructive measurement system for the inspection of magnetic force microscopy (MFM) probes was implemented and discussed in this paper. Its operating system was similar to that used in standard AFM/MFM machines. The MFM probe under test was held on a sample holder and was oscillated by a piezoelectric transducer. The oscillation of the MFM probe was measured by an optical beam deflection technique. In order to measure a response of the MFM probe under the presence of magnetic fields, a solenoid coil was employed as a source for generating the out-of-plane magnetic field. This avoids physical contact which may damage the MFM probe. Different types of MFM probes, including commercial probes and developed in-house probes with different coating thicknesses, were used to demonstrate the system. Experiments revealed a promising result and showed the dependence of the probe sensitivity on the coating thicknesses.

Moisture content is an important quantity for agriculture product, especially in paddy. In principle, the moisture content can be measured by a gravimetric method which is a direct method. However, the gravimetric method is time-consuming. There are indirect methods such as resistance and capacitance methods. In this work, we developed an indirect method based on a 555 integrated circuit timer. The moisture content sensor was capacitive parallel plates using the dielectric constant property of the moisture. The instrument generated the output frequency that depended on the capacitance of the sensor. We fitted a linear relation between periods and moisture contents. The measurement results have a standard uncertainty of 1.23 % of the moisture content in the range of 14 % to 20 %.

Recently, the National Bureau of Agricultural Commodity and Food Standards (ACFS) have drafted a manual of Thai colour rice standards. However, there are no quantitative descriptions of rice colour and its measurement method. These drawbacks might lead to misunderstanding for people who use the manual. In this work, we proposed an inexpensive method, using flatbed scanning together with image analysis, to quantitatively measure rice colour and colour uniformity. To demonstrate its general applicability for colour differentiation of rice, we applied it to different kinds of pigmented rice, including Riceberry rice with and without uniform colour and Chinese black rice.

We use the moiré fringes to measure true stress and true strain of a rubber specimen in tension, and analyze the stress-strain relationship. With the printed straight-line pattern on a specimen, the moiré patterns appear when the specimen is stretched. The geometrical relationship of bright and dark fringes is used to calculate the strain values both in the axial and transverse directions. Together with optical image processing, which can also be used to obtain the instantaneous cross sectional area, we can determine true stress and true strain. The results from the moiré method yield the true stress and true strain in good agreement with those calculated from the standard engineering measurement. Additional benefits of the method include simultaneous measurement of stress and strain, their inhomogeneity, and shear strain.

Wavelet analysis is an excellent technique for data processing analysis based on linear vector algebra since it has an ability to perform local analysis and is able to analyze an unspecific localized area of a large signal. In this work, the wavelet analysis of cyclic waveform was investigated in order to find the distinguishable feature from the cyclic data. The analyzed wavelet coefficients were proposed to be used as selected cyclic feature parameters. The cyclic voltammogram (CV) of different electrodes consisting of carbon nanotube (CNT) and several types of metal phthalocyanine (MPc) including CoPc, FePc, ZnPc and MnPc powders was used as several sets of cyclic data for various types of coffee. The mixture powder was embedded in a hollow Teflon rod and used as working electrodes. Electrochemical response of the fabricated electrodes in Robusta, blend coffee I, blend coffee II, chocolate malt and cocoa at the same concentrations was measured with scanning rate of 0.05V/s from -1.5 to 1.5V respectively to Ag/AgCl electrode for five scanning loops. The CV of blended CNT electrode with some MPc electrodes indicated the ionic interaction which can be the effect of catalytic oxidation of saccharides and/or polyphenol on the sensor surface. The major information of CV response can be extracted by using several mother wavelet families viz. daubechies (dB1 to dB3), coiflets (coiflet1), biorthogonal (Bior1.1) and symlets (sym2) and then the discrimination of these wavelet coefficients of each data group can be separated by principal component analysis (PCA). The PCA results indicated the clearly separate groups with total contribution more than 62.37% representing from PC1 and PC2.

The prototype of depth calibration standard machine was fabricated to calibrate the depth of indentation for elastomer hardness tester. According to ISO 18898, ASTM D2240 and ASTM D1415, the measurement of indentation depth by a measuring device comprising a length-measuring system shall be in reference with the pressure foot of the elastomer hardness tester. Nation Institute of Metrology (Thailand); NIMT develop the depth calibration standard which can measure the indentation depth with always reference at the surface level of pressure foot of the hardness tester at each hardness scale. The calibration of the prototype of depth calibration standard machine was performed to provide the accuracy of the measurement of the machine which can be a suitable standard machine for depth of indentation within 1 μm complied with the requirement of ISO and ASTM standard. Furthermore, the prototype of depth calibration standard machine was validated to another NIMT method, which used the two length-measuring systems. The comparison results between 2 methods showed in a good agreement within 2 μm.

Therefore, the NIMT prototype of depth calibration standard machine can be used as a depth calibration standard for elastomer hardness tester provided the required accuracy of measurement complied with ISO 18898, ASTM D2240 and ASTM D1415.

CuFeO₂ is a metal oxide mineral material which is called delafossite. It can potentially be used as a chemical catalyst, and gas sensing material. There are methods to fabricate CuFeO₂ such as chemical synthesis, sintering, sputtering, and chemical vapor deposition. In our work, CuFeO₂ is prepared by Fused Deposition Modeling (FDM) 3D printing. The composite filament which composed of Cu and Fe elements is printed in three dimensions, and then sintered and annealed at high temperature to obtain CuFeO₂. Suitable polymer blend and maximum percent volume of metal powder are studied. When percent volume of metal powder is increased, melt flow rate of polymer blend is also increased. The most suitable printing condition is reported and the properties of CuFeO₂ are observed by Scanning Electron Microscopy, and Dynamic Scanning Calorimeter, X-ray diffraction. As a new method to produce semiconductor, this technique has a potential to allow any scientist or students to design and print a catalyst or sensing material by the most conventional 3D printing machine which is commonly used around the world.

The blue color of blue sapphire is caused by the Fe-Ti pairs. Recently, the oxidation states of Fe and Ti on high-quality blue sapphire were found as mixed acceptor states of Fe³⁺ and Ti⁴⁺. However, the oxidation states of Fe on natural sapphire with some inclusions were reported as mixing of Fe²⁺ and Fe³⁺ using the x-ray absorption near edge structure spectroscopy (XANES). Generally, there are mineral inclusions on natural sapphire related to Fe such as hematite (Fe₂O₃) and ilmenite (FeTiO₃). In this study, we investigated the micro-inclusions on natural sapphires by the electron probe micro analyzer (EPMA). The oxidation states of Fe and Fe-O bond length were analyzed by x-ray absorption spectroscopy (XAS). The Fe K-edge extended x-ray absorption fine structure (EXAFS) fitting results focused on the first shell of Fe atoms on high-quality natural sapphires were shown that the Fe-O bond length on α-Al₂O₃ was fitted well with the Fe-O bond length of Fe₂O₃ presenting Fe³⁺. However, the Fe-O bond length on natural sapphires with ilmenite micro-inclusion was fitted with the Fe-O bond length of Fe₃O₄ showing Fe²⁺ and Fe³⁺. As the result, the Fe²⁺ on natural sapphires was contributed by the ilmenite micro-inclusion.

Gemstone commercial is a high revenue for Thailand especially ruby and sapphire. Moreover, Phrae is a potential gem field located in the northern part of Thailand. The studies of spectroscopic properties are mainly to identify gemstone using advanced techniques (e.g. UV-Vis-NIR spectrophotometry, FTIR spectrometry and Raman spectroscopy). Typically, UV-Vis-NIR spectrophotometry is a technique to study the cause of color in gemstones. FTIR spectrometry is a technique to study the functional groups in gem-materials. Raman pattern can be applied to identify the mineral inclusions in gemstones. In this study, the natural sapphires from Ban Bo Kaew were divided into two groups based on colors including blue and green. The samples were analyzed by UV-Vis-NIR spectrophotometer, FTIR spectrometer and Raman spectroscope for studying spectroscopic properties. According to UV-Vis-NIR spectra, the blue sapphires show higher Fe³⁺/Ti⁴⁺ and Fe²⁺/Fe³⁺ absorption peaks than those of green sapphires. Otherwise, green sapphires display higher Fe³⁺/Fe³⁺ absorption peaks than blue sapphires. The FTIR spectra of both blue and green sapphire samples show the absorption peaks of –OH,-CH and CO₂. The mineral inclusions such as ferrocolumbite and rutile in sapphires from this area were observed by Raman spectroscope. The spectroscopic properties of sapphire samples from Ban Bo Kaew, Phrae Province, Thailand are applied to be the specific evidence for gemstone identification.

We report the response of graphene and N-doped graphene to ethanol vapor as gas sensors with varying the concentration of ethanol and temperature of graphene. Graphene was synthesized by chemical vapor deposition on copper foils and then was transferred to a glass slide by chemical etching. N-doped graphene was produced by annealing graphene in ammonia atmosphere. Results showed the response of both graphene and N-doped graphene are at low level up to 2.4%. The response of graphene increases with temperature up to 1.15%, but that of N-doped graphene decreases down to 0.30%. We proposed that the absorbed oxygen and nitrogen detachment are the key factors for the temperature dependence of the response of graphene and N-doped graphene, respectively.

The formation of polymeric materials can be achieved by several methods such as melting and casting, screw extrusion, cross-linking of resin or rubber in a mold, and so on. In this work, the polyacrylic acid is formed by using the emulsion disturbance method. Despite extensively used in the colour painting and coating industries, acrylic emulsion can be processed into a foam and powder configuration by a reaction between acrylic emulsion and salt. The solidification hardly changes the volume between liquid emulsion and solidified polymer which means the final structure of polyacrylic acid is filled with opened air cells. The opened air cell structure is confirmed by the result from scanning electron microscopy. The chemical analysis and crystallography of acrylic powder and foam are examined by Fourier-transform infrared spectroscopy and X-ray diffraction respectively. The phase transformation and Thermal stability are studied by differential scanning calorimetry and thermo gravimetric analysis. Moreover, the mechanical properties of acrylic foam were observed by tensile, compressive and hardness test. In addition to the basic property analysis, acrylic foam was also used in the particle filtration application.

In this work, CaCu₃Ti_4-x(Nb_1/2In_1/2)_xO₁₂ ceramics, x = 0, 0.025, 0.05, 0.10, and 0.20, were prepared using a conventional solid state reaction method. Their crystal structure, microstructure, dielectric, and electrical properties were systematically investigated. A primary phase of CaCu₃Ti₄O₁₂ ceramic was clearly observed in all samples. The average grain size of CaCu₃Ti₄O₁₂ was decreased by (Nb⁵⁺, In³⁺) doping. The dielectric permittivity of CaCu₃Ti_4-x(Nb_1/2In_1/2)_xO₁₂ ceramics was slightly dependent on frequency as the co-dopant concentration increased, which was due to a decrease in its grain size. Their dielectric behavior can be well described by the internal barrier layer capacitor (IBLC) model based on interfacial polarization at grain boundaries. The grain boundary resistance and potential barrier height at the grain boundary of CaCu₃Ti₄O₁₂ were reduced by co–doping with (Nb⁵⁺, In³⁺) ions, resulting in an enhancement of DC conductivity and the related dielectric loss tangent.

Polypyrrole (PPy) have been considered as one of the most promising conducting polymers for gas sensor application because it can be efficiently operated at room temperature, light weight, thermal stability and ease of preparation. In this work, we have investigated the geometric and electronic structures of PPy based on B3LYP/3-21G*, B3LYP/6-31G* and SCC-DFTB methods. The effects of polymer chain length of PPy on structural and electronic properties including bond length, bond angle, torsion angle, the highest occupied orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and energy gap have been studied from the optimized PPy oligomers (n=1-10). The results show that the bond length, bond angle and torsion angle from SCC-DFTB method are C-N = 1.38 Å, N-H = 1.04 Å, C-C = 1.45 Å, N-C-C = 122 °, C-C-C = 131 °, N-C-C-C = 179 ° and C=C-C=C = 179 °, respectively. The HOMO and LUMO are in range of -5.49 to -4.23 eV and -0.078 to-1.92 eV, respectively. The energy gap decreases with increasing polymer chain length from 5.41 to 2.31 eV. Furthermore, sensing behavior of PPy for detection of toxic gases such as ammonia (NH₃), carbon dioxide (CO₂) and nitrogen dioxide (NO₂) has been studied and discussed in details.

The schiff base was synthesized by 2,5-thiophenedicarboxaldehyde and 1,2,4-thiadiazole-3,5-diamine with condensation method. There was modified on carbon paste electrode (CPE) and Printed circuit board (PCB) gold electrode for determination silver ion. The schiff base modified electrodes was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The electrochemical study was reported by cyclic voltammetry method and impedance spectroscopy using modified electrode as working electrode, platinum wire and Ag/AgCl as counter electrode and reference electrode, respectively. The modified electrodes have suitable detection for Ag⁺. The determination of silver ions using the modified electrodes depended linearly on Ag⁺ concentration in the range 1×10^-10 M to 1×10^-7 M, with cyclic voltammetry sensitivity were 2.51×10⁸ μAM^-1 and 1.88×10⁸ μAM^-1 for PCB gold electrode and CPE electrode, respectively, limits of detection were 5.33×10^-9 M and 1.99×10^-8 M for PCB gold electrode and CPE electrode, respectively. The modified electrodes have high accuracy, inexpensive and can applied to detection Ag⁺ in real samples.

This research is a simulated and experimental study on effects of bipolar electrodes of a PEM fuel cell on its power conversion efficiency. The PEM fuel cell structure consists of bipolar electrodes, proton exchange membrane with catalysts, flow channels of gases. This research used fuel cell of 49 cm² in active area as a research sample and the Comsol 4.4 was employed to simulate flow channels which are serpentine pattern for anode and parallel pattern for cathode. The parameters used were calculated effects of such parameters using Comsol 4.4. After the calculation has been completed, the prototype of the PEM fuel cell were fabricated using graphite plate as electrodes which had the channel height of 0.20 cm, proton exchange membrane using carbon-platinum catalyst. Finally, further it was found that the effect of temperature on the power conversion efficiency is not severely. And for anode, the concentration of hydrogen gas was reduced 64 wt% due to the reaction whereas in parallel channel of cathode the oxygen concentration was reduced by only 6 wt% from 23 wt% at the entrance to 17 wt% at the end. The maximum power output of the prototype operated under such condition was 0.28 W/cm² calculated from maximum power output voltage (Vmp) of 0.70 V and maximum power output current density of 0.42 A/cm² which was in good agreement with that simulated using Comsol 4.4 which revealed the power output of 0.29 W/cm².

Hydroxyapatite-ZrO₂ composite ceramic were synthesized using a thermal precipitation techniques. The chemical precursors were prepared from di-ammonium hydrogen orthophosphate, calcium oxide (CaO) derived from chicken eggshell, zirconium dioxide (ZrO₂) and distilled water. The mixture were heated at the various temperatures from 100 to 700 °C in the furnace with an incremental temperature of 100 °C. The ZrO₂ contents in the composite ceramic were varied from 0 to 15 percent weight of CaO. The prepared composites were then annealed at 300, 600 and 700 °C for 4 h in air. The crystal structure, function group and morphology of all samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and universal testing machine (UTM), respectively. The results indicated that the undoped-ZrO₂ samples hydroxyapatite phase with a hexagonal structure. However, the hydroxyapatite was transformed to the tri-calcium phosphate after thermal treatment at 700 °C. For the doped-ZrO₂ samples, the hydroxyapatite and ZrO₂ phases were found. Moreover, the result showed that the compressive strength of hydroxyapatite-ZrO₂ composite ceramic increased with increasing the ZrO₂ content.

The aim of this work was to compare characteristics of hydroxyapatite synthesized by precipitation and ball milling techniques. The cuttlefish bone powder was a precursor in calcium source and the di ammonium hydrogen orthophosphate powders was a precursor in phosphate source. The hydroxyapatite was synthesized by the both techniques such as precipitation and ball milling techniques. The phase formation, chemical structure and morphology of the both hydroxyapatite powders have been examined by X-ray diffractometer (XRD), Fourier transform infrared spectroscope (FTIR) and field emission scanning electron microscope (FESEM), respectively. The results show that the hydroxyapatite synthesized by precipitation technique formed hydroxyapatite phase slower than the hydroxyapatite synthesized by ball milling technique. The FTIR results show the chemical structures of sample in both techniques are similar. The morphology of the hydroxyapatite from the both techniques were sphere like shapes and particle size was about in nano scale. The average particle size of the hydroxyapatite by ball milling technique was less than those synthesized by precipitation technique. This experiment indicated that the ball milling technique take time less than the precipitation technique in hydroxyapatite synthesis.

Pt counter electrode was coated by electrochemical method. Electrolyte solution was synthesized by platinum (IV) choloride (PtCl₄) powder dissolved in hydrochloric acid solution. Pt films were deposited on the FTO substrate. Deposition time of 10, 30 and 60 minutes, the coating current of 5, 10, 15 and 20 mA and electrolyte solution temperatures for Pt layer synthesis of 25, 30 and 40°C were varied. Surface morphology and optical properties was analyzed by digital microscopic and UV-vis spectrophotometer. Pt films exhibit uniform surface area highly for all the conditions of coating current in the deposition time of 30 and 40 minutes at 40°C. Transmittance values of Pt films deposited on FTO substrate has approximately of 5 to 50 % show that occur high reflection corresponding to dye molecule absorption increases. DSSC device was fabricated from the TiO₂ standard and immersed in dye N719 for 24 hours. Efficiency was measured by solar simulator. Efficiency value obtains as high as 5.91 % for the coating current, deposition time and solution temperature of 15 mA, 30 minutes and 40°C. Summary, influence of temperature effects efficiency increasing. Pt counter electrode can be prepared easily and the suitable usefully for DSSC.

Nanocomposite piezoelectric films based on the blend of poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP) and magnesium chloride hexahydrate (MgCl₂•6H₂O) have been investigated in this work. The films incorporated with 0.5 wt% MgCl₂•6H₂O were prepared using a solution casting technique and uniaxially stretched at various ratios from 2 to 6 times in order to characterize phase transformation, surface morphology and dielectric behaviour. The piezoelectric β phase transformation and crystallinity of the stretched films were identified by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). A scanning electron microscopy (SEM) was conducted to observe the surface microstructure and porosity. The frequency dependence of dielectric properties was also measured by LCR meter at room temperature. The stretched films show the larger the stretching ratio, the greater the microdefects appearance. This leads to a decrease of dielectric constant with stretching ratio. Nevertheless, the P(VDF-HFP) nanocomposites with stretching ratio of 4 times display a higher β phase fraction of 90% than the unstretched films. Thus, this result points out that the β phase transformation of the composite films can be enhanced by mechanically stretching process.

Lightweight aggregates were prepared from fly ash of by-products from the paper industry. The influence of the ratio of clay to fly ash and processing conditions on lightweight aggregates properties were investigated. It was found that the amount of fly ash directly affected to porosity of lightweight aggregates. Lightweight aggregates with the ratio of clay to fly ash at 80:20 wt% using the sintering temperature at 1210°C exhibits bulk density of 1.66 g cm^-3, compressive strength of 25 MPa and water absorption of 0.55%. The replacement of coarse aggregates with lightweight aggregates at 100 wt% for concrete production showed the ultimate properties of concrete with density of 1780 g cm^-3, water absorption of 3.55%, compressive strength of 40.94 MPa and thermal conductivity of 0.77 W m^-1K^-1. The concrete had more than 25% weight reduction while keeping a similar compressive strength to an ordinary concrete. This is revealed that lightweight aggregates could be applied into structural concrete because it was able to reduce work load and increase safety factor of construction.

This research investigates physical and electrical properties of Mn_1-xMg_xFe₂O₄ (MMF) ceramics which were prepared by co–precipitation method. The ratio values of doping were varied with x = 0.3, 0.4 and 0.5. MMF ceramics were calcined at 1100 °C and sintered at 1200 °C 1300 °C and 1400 °C respectively. The effects of Mg content and sintered temperatures on the density by the Archimedes method, the phase formation by XRD, the morphology by SEM and electrical properties were investigated. The study found at ratio of x = 0.3 sintered at 1400 °C. The sample had maximized density of 3.58 g/cm³. The XRD analysis of the synthesized powders confirmed the formation of the single phase MnMgFe₂O₄ cubic spinel structure. The microstructure exhibited a rectangular square grain in all samples. The average grain size of the ceramics increased from 7.7 μm to 13.7 μm. The dielectric constant value increases when temperatures increase.

This research studied about an epoxy molding compound (EMC) floor life to reliability performance of integrated circuit (IC) package. Molding is the process for protecting the die of IC package form mechanical and chemical reaction from external environment by shaping EMC. From normal manufacturing process, the EMC is stored in the frozen at 5oC and left at around room temperature for aging time or floor life before molding process. The EMC floor life effect to its properties and reliability performance of IC package. Therefore, this work interested in varied the floor life of EMC before molding process to analyze properties of EMC such as spiral flow length, gelation time, and viscosity. In experiment, the floor life of EMC was varied to check the effect of its property to reliability performance. The EMC floor life were varied from 0 hours to 60 hours with a step of 12 hours and observed wire sweep, incomplete EMC, and delamination inside the packages for 3x3, 5x5 and 8x8 mm2 of QFN packages. The evaluation showed about clearly effect of EMC floor life to IC packaging reliability. EMC floor life is not any concern for EMC property, moldabilty, and reliability from 0 hours to 48 hours for molding process of 3x3,5x5 and 8x8 mm2 QFN packaging manufacturing

This research studied about warpage of QFN package in post mold cure process of integrated circuit (IC) packages using pre-plated (PPF) leadframe. For IC package, epoxy molding compound (EMC) are molded by cross linking of compound stiffness but incomplete crosslinked network and leading the fully cured thermoset by post mold cure (PMC) process. The cure temperature of PMC can change microstructure of EMC in term of stress inside the package and effect to warpage of the package due to coefficient of thermal expansion (CTE) between EMC and leadframe. In experiment, cure temperatures were varied to check the effect of internal stress due to different cure temperature after completed post mold cure for TDFN 2×3 8L. The cure temperature were varied with 180 °C, 170 °C, 160 °C, and 150°C with cure time 4 and 6 hours, respectively. For analysis, the TDFN 2×3 8L packages were analyzed the warpage by thickness gauge and scanning acoustic microscope (SAM) after take the test samples out from the oven cure. The results confirmed that effect of different CTE between EMC and leadframe due to different cure temperature resulting to warpage of the TDFN 2×3 8L packages.

This research studied about effecting aging time of epoxy molding compound (EMC) that effect to reliability performance of integrated circuit (IC) package in molding process. Molding process is so important of IC packaging process for protecting IC chip (or die) from temperature and humidity environment using encapsulated EMC. For general molding process, EMC are stored in the frozen at 5°C and left at room temperature at 25 °C for aging time on self before molding of die onto lead frame is 24 hours. The aging time effect to reliability performance of IC package due to different temperature and humidity inside the package. In experiment, aging time of EMC were varied from 0 to 24 hours for molding process of SOIC-8L packages. For analysis, these packages were tested by x-ray and scanning acoustic microscope to analyze properties of EMC with an aging time and also analyzed delamination, internal void, and wire sweep inside the packages with different aging time. The results revealed that different aging time of EMC effect to properties and reliability performance of molding process.

In this work, magnetic force microscopy (MFM) was utilized to observe the magnetic write head remanence, which is the remaining out-of-plane magnetic field on magnetic write heads after a write current is turned off. This remnant field can write unwanted tracks or erase written tracks on a magnetic media. The write head remanence can also occur from device and slider fabrication, either by applying current to the write coil during the inspection or biasing the external magnetic field to magnetic recording heads. This remanence can attract magnetic nanoparticles, which is suspended in cleaning water or surrounding air, and cause device contamination. MFM images were used to examine locations of the remnant field on the surface of magnetic recording heads. Experimental results revealed that the remanence occurred mostly on the shield and is dependent on the initial direction of magnetic moments. In addition, we demonstrated a potential use of MFM imaging to investigate effects of different etching gases on the head remanence.

In this paper, magnetic force microscopy (MFM) probes with different coating materials were characterized under AC magnetic field. A perpendicular magnetic write head similar to those used in hard disk drives was employed as the AC magnetic field generator. In order to measure a response of MFM probes to AC magnetic field, a MFM probe under test was scanned, at a scan height of 10 nm, across the surface of the magnetic write head. During MFM imaging, the write head was biased by a sufficient magnitude of AC current, approximately 30 mA. A spectral analysis for a frequency sweep from 1 kHz to 100 MHz was extracted from post-processing MFM images. As expected, a MFM probe coated with hard magnetic alloys, i.e. FePt, has the lowest response to AC magnetic fields. MFM probes coated with soft magnetic alloys, i.e. NiFe and NiCoCr, have a relatively high and flat response across the frequency range. Ni coated MFM probe has the highest response to AC magnetic fields. In addition, CoCr and NiCo coated MFM probes show lower response than NiFe and NiCoCr probes at low frequencies; however, theirs response to AC magnetic field increase for the AC magnetic field with a frequency above 50 kHz. This can be implied that those MFM probes are a good candidate for being used to study the high-frequency performance of perpendicular magnetic write heads. Noting that response of all MFM probes significantly decreased when driven frequencies above 1 MHz due to the limitation of the hardware, i.e. response of quadrant photodiode and op-amp in a pre-amplifier.

Magnetic force microscopy (MFM) was employed to characterize the magnetic field distribution of two different designs of perpendicular magnetic writers with fully wrap-around shield (WAS). Typical magnetic write heads, located on a slider at the so-called air bearing surface (ABS), are composed of a magnetic write pole and a magnetic return pole. The write pole has a much small cross section area at the ABS than the return pole which is connected to magnetic shield. The write pole and the shield are separated by a non-magnetic gap layer. The shield structure is designed in such a way that it can confine the magnetic fields without significantly degrading field strength. In this work, MFM imaging was used to investigate the relationship between the gap structure and magnetic field strength/gradient. Magnetic field distributions of two different head designs were compared and discussed in detail. Experimental results revealed that the magnetic field intensity is linearly proportional to pole dimensions, especially the pole width. The field gradient, however, is dependent on not only spacing gap between shields and the write pole, but also the pole widths and thicknesses.

We used a phase-contrast magnetic force microscopy (MFM) to observe and analyze the failure of magnetic write heads due to the WATEr problem, which limits the off-track performance. During MFM imaging, the magnetic write head was energized by a DC current. The induced out-of-plane magnetic field was then detected by scanning a MFM probe across the surface of the magnetic write head. MFM images were then mapped with WATEr measured results from a spin stand method. Results showed that WATEr effect can be generated by several factors, i.e. the structure of magnetic domains and walls from material discontinuities and the magnetic field leakage at different locations on magnetic write heads. Understanding WATEr mechanisms is useful for design and process development engineers.

Titanium dioxide (TiO₂) nanostructures were prepared by time varied microwave assisted. The morphology of TiO₂ nanostructures was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD). SEM images revealed the agglomeration of TiO₂ nanostructures with the size of 20-70 μm. The XRD patterns showed anatase phase of TiO₂ with peaks of (101), (004), (200), (105), (211) and (204). The I-V characteristics exhibited the behavior of the ohmic and diode materials. The sensitivity which was measured under CO₂ atmosphere at room temperature showed high sensitivity of TiO₂/GO composites of 2.55 for 60 seconds.

In this study, we have successfully parameterized the coarse-grained (CG) model of cis-1,4-polyisoprene (main component of natural rubber) based on the MARTINI force field. An isoprene monomer is mapped into one bead of CG model. The structure, bulk and thermodynamics properties of cis-1,4-polyisoprene with new CG model are well comparable to the atomistic simulation model and experiment. Our CG model of cis-1,4-polyisoprene will be helpful to study in the advanced rubber nanocomposite materials.

CuO nanoparticles (CuO NPs) were used as a barrier layer in ZnO dye-sensitized solar cells (DSSCs) to obtain high power conversion efficiency. The barrier layer was investigated in terms of the size of CuO NPs by varying power of pulsed Nd:YAG (1064 nm) laser ablation. Morphological and optical properties of CuO NPs were characterized by transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-vis) and dynamic light scattering (DLS). It was found that the CuO NPs are rather spherical in shape with diameter in between 20 - 132 nm. In addition, the energy gap of CuO decreases with the increase of CuO NPs size. The power conversion efficiency of ZnO DSSCs was measured under illumination of simulated sunlight obtained from a solar simulator with the radiant power of 100 mW/cm². The results showed that the ZnO DSSC with the CuO NPs with size of 37 nm exhibits the optimum power conversion efficiency of 1.01% which is higher than that of one without CuO NPs. Moreover, the power conversion efficiency of the ZnO DSSCs decreases with the increase of CuO NPs size.

This research presents a study of aggregation of colloidal gold nanoparticles using 400 nm diameter gold nanoparticles mixed with a surfactant (Plantacare 2000) at various concentrations. When observed under a microscope, we found that the nanoparticles aggregated to form nearly spherical clusters at the beginning of the formation, and then sedimented to the bottom of the container. These clusters moved with Brownian's motion and collided with each other in the horizontal plane, forming branch-like clusters in 2D. The appearance and size of the clusters were different depending on the concentration of surfactant. The clusters' size and appearance were rarely changed after mixing with surfactant for 90 minutes, and we found that the cluster's shapes were nearly spherical at low surfactant concentration (c = 0.25%). At surfactant concentration between 0.50% - 5.00%, the aggregates formed branch-like clusters with skinnier branches and smaller sizes at higher surfactant concentration. Moreover, we also found that, at surfactant concentrations between 2.50% - 5.00%, nanoparticles and aggregates stuck to the bottom of the glass container quickly and rarely moved after 10 minutes. At c = 0.25%, the 2D fractal dimension of the aggregates was measured to be D = 1.88 ± 0.04, since the aggregates were nearly spherical. The fractal dimension decreased to the minimum of D = 1.50 ± 0.12 at c = 1.50%, similar to D ∼ 1.45 found in diffusion-limited cluster aggregation (DLCA). At surfactant concentration above 1.50%, the fractal dimension increased until it reached the value of D ∼ 1.66 at c = 5.00%.

Titanium dioxide (TiO₂) thin films have been generally accepted as an important material in the fields of photocatalysis, photovoltaic and photochromic. The efficiency of TiO₂ films as an active layer in various applications strongly depends on their optical properties. In this present study, the optical properties of sputtered TiO₂ thin films were modified using nanoparticles gold (Au) underlayer. TiO₂ thin films with 100 nm thicknesses were prepared by DC magnetron sputtering on gold coated glass substrates with the estimated thickness approximately 2, 6 and 10 nm. The deposited TiO₂/Au films were characterized using UV-Vis spectroscopy and photoluminescence (PL) spectroscopy. The transmittance of TiO₂/Au film in visible region decreased from 87% to 50% when thickness of gold underlayer increased from 0 to about 10 nm. In addition, energy gap of TiO₂/Au film from Tauc's plot decreased with the increase of the thickness of gold underlayer while the wavelength of peak emission spectra obtained from PL were found to be increased. The modified optical properties indicated the probability of light absorption which may lead to the increase in electron-hole pair generation in this composite film.

ZnO nanorod arrays have become to attract much attention because the uniform and symmetry of ZnO nanorods can provide great optical and electrical potential in many nanodevices. Here, we have controlled nucleation sites using electron beam lithography technique and grown ZnO nanorods via hydrothermal synthesis to observe growth behaviors. We have measured nanorods's diameter and density of each aperture area. The results are presented strongly effect of aperture size and distance between adjacent apertures for growth ZnO nanorods. The both of aperture size and distance affect not only nanorod's density and diameter but also nucleation growth and growth rate. There is no nanorod growth through aperture area when aperture size is large and distance between apertures is small. In the same growth condition, there are several nanorods growth through large aperture size with large distance between apertures. These phenomena show behavior of ZnO nanorods growth with difference aperture size and distance which are useful to enhance great properties ZnO nanorods and also achieve high performance of nanodevices.

CaCu₃Ti₄O₁₂ powders were synthesized by modified Sol-gel method with Hydrothermal process using Ca(NO₃)₂· 4H₂O, Cu(NO₃)₂·3H₂O, Ti(OC₃H₇)₄ and freshly extracted egg white (ovalbumin) in aqueous medium. The precursor was calcined at 800, 900 and 1000 °C in air for 8 h to obtain nanocrystalline powders of CaCu₃Ti₄O₁₂. The calcined CaCu₃Ti₄O₁₂ powders were characterized by XRD, TEM and EDX. The XRD results indicated that all calcined samples have a typical perovskite CaCu₃Ti₄O₁₂ structure and a small amount of CaTiO₃, CuO and TiO₂. TEM micrographs showed particle size 100 - 500 nm and EDX results showed elements of CaCu₃Ti₄O₁₂ powders have calcium, copper, titanium and oxygen.

First-principles calculations based on density functional theory (DFT) are carried out to study the adsorption behaviours of molecular H₂ on the graphene-like material C₂N. The plausible adsorption sites on top of bonds, on carbon atom and nitrogen atom and the center of C-C hexagon and the C-N hexagon are considered. The calculated adsorption energies are found to be in the physisorption regime. We find that the most favourable site of H₂ is above the center of C-N hexagon. In addition, we demonstrate the inclusion of the Van der Waals interactions through the DFT-D2 method via the generalized gradient approximation (GGA) functional gives the consistent trend of H₂ adsorption with that obtained via the local-density approximation (LDA) functional. The effects of Van der Waals interactions on the adsorption energies and equilibrium distance between H₂ and C₂N are discussed.

By making use of advanced technique of the near-field Talbot effect, we design a novel spectrometer. Our method provides a compact and portable spectrometer according to the characteristic of the Talbot effect. Here, we propose the idea with the simulations done with reasonable values. With vibration and temperature adjustments, the high resolution over a range of a few nanometers can be obtained.

The aim of this work is to investigate the laser cleaning of contaminants from surfaces of silica nanowires. Experimental parameters affected particle removal were explored using pulsed fiber laser radiation at a wavelength of 1064 nm. The laser beam was focused and scanned across the surfaces of the nanowires. The interaction between laser radiation and a certain thickness in the contaminant layers was analyzed. The results suggest that low laser fluencies allow greater control over the removal depth reducing the risk of damage. The cleaning efficiency was determined. The laser cleaning technique can open up completely challenges in applications of nanophotonics.

A dual wavelength laser system providing emissions of 1064 nm and 532 nm was developed for cleaning applications. In this study, cleaning of surface layers of paints with the dual wavelength laser system was demonstrated. The results reveal that the laser system was able to control the depth of material removed. The cleaning efficiency was evaluated with varied conditions. With several advances, the dual wavelength laser cleaner operating in infrared and visible region will become an establish tool in non-contact cleaning applications.

This paper reviews recent progress in the digital holographic 3D imaging spectrometry. The principle of this method is a marriage of incoherent holography and Fourier transform spectroscopy. Review includes principle, procedure of signal processing and experimental results to obtain a multispectral set of 3D images for spatially incoherent, polychromatic objects.

The microring resonators have potential applications for the photonic integrated circuits. The dynamical phenomena of the two coupled microrings require a simple and efficient numerical formalism for solution of the system. We employ an analytical formula to calculate the optical tristability inside the two coupled microrings that takes into account Kerr nonlinearity and the effect of loss. We also compare the analytical results with the results from 3D finite-difference time-domain simulation. In addition, we show it is possible to obtain configurations which can tune the tristable region. This could be useful for designing optical logic applications.

Heart rate monitoring via optically remote noncontact technique was reported in this research. A green laser (5 mW, 532±10 nm) was projected onto the left carotid artery. The reflected laser light on the screen carried the deviation of the interference patterns. The interference patterns were recorded by the digital camera. The recorded videos of the interference patterns were frame by frame analysed by 2 standard digital image processing (DIP) techniques, block matching (BM) and optical flow (OF) techniques. The region of interest (ROI) pixels within the interference patterns were analysed for periodically changes of the interference patterns due to the heart pumping action. Both results of BM and OF techniques were compared with the reference medical heart rate monitoring device by which a contact measurement using pulse transit technique. The results obtained from BM technique was 74.67 bpm (beats per minute) and OF technique was 75.95 bpm. Those results when compared with the reference value of 75.43±1 bpm, the errors were found to be 1.01% and 0.69%, respectively.

The purpose of this study is to estimate thermal diffusivities of high thermal diffusivity bulk material as well as low thermal diffusivity bulk material by using many types of fluid such as Ethyl alcohol and water. This method is studied by measuring amplitude and phase of photodeflection signal in various frequency modulations. The experimental setup consists of two laser lines: 1) a pump laser beams through a modulator, varied frequency, controlled by lock-in amplifier and focused on sample surface by lens. 2) a probe laser which parallels with the sample surface and is perpendicular to the pump laser beam. The probe laser deflection signal is obtained by a position sensor which controlled by lock-in amplifier. Thermal diffusivity is calculated by measuring the amplitude and phase of the photodeflection signal and compared with the thermal diffusivity of a standard value. The thermal diffusivity of SGG agrees well with the literature but the thermal diffusivity of Cu is less than the literature value by a factor of ten. The experiment requires further improvement to measure the thermal diffusivity of Cu. However, we succeed in using ethyl alcohol as the coupling medium instead of CCl4 which is highly toxic.

During the last year we have made progresson a development of a frequency-doubled 532 nm Nd:YVO₄ laser pumped by solar light. The research aimed to demonstrate solar pumped lasers consisting of the optically contracted Nd:YVO₄ crystal and KTP crystal with a system of laser mirrors deposited onto crystal sides. The Cassegrain reflector is used as the configuration. This solar pumped laser system is appealing for a variety applications including laser communication, imaging and defense applications.

The functional transformation method (FTM) is a powerful tool for detailed investigation of digital sound synthesis by the physical modeling method, the resulting sound or measured vibrational characteristics at discretized points on real instruments directly solves the underlying physical effect of partial differential equation (PDE). In this paper, we present the Higuchi's method to examine the difference between the timbre of tone and estimate fractal dimension of musical signals which contains information about their geometrical structure that synthesizes by FTM. With the Higuchi's method we obtain the whole process is not complicated, fast processing, with the ease of analysis without expertise in the physics or virtuoso musicians and the easiest way for the common people can judge that sounds similarly presented.

Chiral Phospholipids are found self-assembled into cylindrical tubules of 500 nm in diameter by helical winding of bilayer stripes under cooling in ethanol and water solution. Theoretical prediction and experimental evidence reported so far confirmed the modulated tilt direction in a helical striped pattern of the tubules. This molecular orientation morphology results in optically birefringent tubules. We investigate an individual lipid microtubule under a single optical trap of 532 nm linearly polarized laser. Spontaneous rotation of a lipid tubule induced by radiation torque was observed with only one sense of rotation caused by chirality of a lipid tubule. Rotation discontinued once the high refractive index axis of a lipid tubule aligned with a polarization axis of the laser. We further explored a lipid tubule under circularly polarized optical trap. It was found that a lipid tubule was continuously rotated confirming the tubule birefringent property. We modified the shape of optical trap by cylindrical lens obtaining an elliptical profile optical trap. A lipid tubule can be aligned along the elongated length of optical trap. We reported an investigation of competition between polarized light torque on a birefringent lipid tubule versus torque from intensity gradient of an elongated optical trap.

In this work, the motion of a particle in one dimension under the influence of the linearly downward potential well is studied within the context of the non-relativistic quantum mechanics. The attention is paid on the paradoxical phenomenon of the reflection of a particle that is in contrast between classical and quantum physics. Classically, the reflection effect occurs only at a potential barrier. To demonstrate such counter-intuitive phenomenon, the Schrödinger equation is solved to obtain the reflection coefficient in the scattering state by considering an incident particle that is represented by a monochromatic plane wave having an energy E > 0, propagates freely from left to right, pass through the potential well. The continuity conditions at boundaries give the desired result that is expressed in terms of the Airy functions which depends on the incident energy E, the strength jV₀j and the range L of the well. The value of the reflection coefficient R lies in the interval 0 < R < 1, and its behavior is the decreasing function with respect to the range L.

In this work, we developed an affordable modern innovative physics lab apparatus. The ultrasonic sensor is used to measure the position of a mass attached on a spring as a function of time. The data acquisition system and control device were developed based on LabVIEW interface for Arduino UNO R3. The experiment was designed to explain wave propagation which is modeled by simple harmonic motion. The simple harmonic system (mass and spring) was observed and the motion can be realized using curve fitting to the wave equation in Mathematica. We found that the spring constants provided by Hooke's law and the wave equation fit are 9.9402 and 9.1706 N/m, respectively.

The purpose of this work is to build a physics lab apparatus that is modern, low-cost and simple. In one dimensional two-body collisions experiment, we used the Arduino UNO R3 as a data acquisition system which was controlled by LabVIEW program. The photogate sensors were designed using LED and LDR to measure position as a function of the time. Aluminium frame houseware and blower were used for the air track system. In both totally inelastic and elastic collision experiments, the results of momentum and energy conservation are in good agreement with the theoretical calculations.

Students always bring intuitive ideas about physics into classes, which can impact what they learn and how successful they are. To examine what Cambodian students think about projectile motion, we have developed seven open-ended questions and applied into grade 11 students before (N=124) and after (N=131) conventional classes. Results revealed several consistent misconceptions, for instance, many students believed that the direction of a velocity vector of a projectile follows the curved path at every position. They also thought the direction of an acceleration (or a force) follows the direction of motion. Observed by a pilot sitting on the plane, the falling object, dropped from a plane moving at a constant initial horizontal speed, would travel backward and land after the point of its release. The greater angle of the launched projectile creates the greater horizontal range. The hand force imparted with the ball leads the ball goes straight to hit the target. The acceleration direction points from the higher position to lower position. The misconceptions will be used as primary resources to develop instructional instruments to promote Cambodian students' understanding of projectile motion in the following work.

Interactions in the Sun-Earth-Moon System are common misconception for students. Pre-service teacher should develop the lesson plans about the Sun-Earth-Moon system for their professional experience in school. In this work, we investigated understanding of 26 pre-service teachers in the topic of Sun-Earth-Moon system, emphasize on moon phase concept. They studied the earth science, astronomy and space concept learning management course in the first semester of academic year 2016 (August to December 2016). An open-ended question about cause of moon phase is mainly used as research tool. Their responses had been interpreted and categorized into level of understanding by considering key-words, such as, the earth, the moon and the sun. The result revealed that most pre-service teachers have suitable concepts but not all of the components and some of them contain misconception. The founding would be brought into the course for designing lesson plan and tools for improve concept about the moon phase.

This study aimed to develop the process of STEM Education activity design used in Physics subjects in the Thai secondary schools. The researchers have conducted the study by reviewing the literature and related works, interviewing Physics experts, designing and revising the process accordingly, and experimenting the designed process in actual classrooms. This brought about the five-step process of STEM Education activity design which Physics teachers applied to their actual teaching context. The results from the after-class evaluation revealed that the students' satisfaction level toward Physics subject and critical thinking skill was found higher statistically significant at p < .05. Moreover, teachers were advised to integrate the principles of science, mathematics, technology, and engineering design process as the foundation when creating case study of problems and solutions.

Alternative energy tends to be more widespread in Thailand because the advanced technology, enhance the potential of equipment which becomes more economically rather than setting in laboratory likes in the past. For this reason students should understand profoundly about the characteristic of energy before they learned about alternative energy. To help students get more comprehension about the characteristic of energy, we need to investigate the idea about energy. There are three main reasons for the investigation (1) to know how students use analogy to describe characteristic of energy (2) to find out the most frequent characteristic that student used (3) to classify analogies for energy by using category of misconceptions which helped us to group students if there were any vague content in students' explanation. Students were given a task to write their analogies after doing the STEM activity (Bungee Jump) in class. The answers were categorized into four terms of scientific contexts: energy can be accounted, can change forms, can be lost and can be transferred.

A set of lenses was fabricated from a low cost materials in a DIY (Do it yourself) process. The purpose was to demonstrate to teachers and students in high schools how to construct lenses by themselves with the local available materials. The lenses could be applied in teaching Physics, about the nature of a lens such as focal length and light rays passing through lenses in either direction, employing a set of simple laser pointers. This instrumental kit was made from a transparent 2 mm thick of acrylic Perspex. It was cut into rectangular pieces with dimensions of 2x15 cm² and bent into curved shape by a hot air blower on a cylindrical wooden rod with curvature radii of about 3-4.5 cm. Then a pair of these Perspex were formed into a hollow thick lenses with a base supporting platform, so that any appropriate liquids could be filled in. The focal length of the lens was measured from laser beam drawing on a paper. The refractive index, n (n) of a filling liquid could be calculated from the measured focal length (f). The kit was low cost and DIY but was greatly applicable for optics teaching in high school laboratory.

The objectives of this study were to develop and assess student understanding of measurement and uncertainty. A test has been adapted and translated from the Laboratory Data Analysis Instrument (LDAI) test, consists of 25 questions focused on three topics including measures of central tendency, experimental errors and uncertainties, and fitting regression lines. The test was evaluated its content validity by three physics experts in teaching physics laboratory. In the pilot study, Thai LDAI was administered to 93 freshmen enrolled in a fundamental physics laboratory course. The final draft of the test was administered to three groups—45 freshmen taking fundamental physics laboratory, 16 sophomores taking intermediated physics laboratory and 21 juniors taking advanced physics laboratory at Chiang Mai University. As results, we found that the freshmen had difficulties in experimental errors and uncertainties. Most students had problems with fitting regression lines. These results will be used to improve teaching and learning physics laboratory for physics students in the department.

In higher education, lecturing has been found to be the most prevalent teaching format for large classes. Generally, this format tends not to result in effective learning outcomes. Therefore, to support student learning in these large lecture classes, we developed guided notes containing quotations, blank spaces, pictures, and problems. A guided note taking strategy was selected and has been used in our introductory physics course for many years. In this study, we investigated the results of implementing the guided note taking strategy to promote student learning on electrostatics. The samples were three groups of first-year students from two universities: 163 and 224 science students and 147 engineering students. All of the students were enrolled in the introductory physics course in the second semester. To assess the students' understanding, we administered pre- and post-tests to the students by using the electrostatics test. The questions were selected from the conceptual survey of electricity and magnetism (CSEM) and some leading physics textbooks. The results of the students' understanding were analyzed by the average normalized gains (<g>). The <g> value of each group was 0.61, 0.55, and 0.54, respectively. Furthermore, the students' views on learning with the guided note taking strategy were explored by using the five-point rating scale survey. Most students perceived that the strategy helped support their active learning and engagement in the lectures.

This study aimed to investigate students' understanding and develop instructional material on a topic of simple harmonic motion. Participants were 60 students taking a course on vibrations and wave and 46 students taking a course on Physics 2 and 28 students taking a course on Fundamental Physics 2 on the 2nd semester of an academic year 2016. A 16-question conceptual test and tutorial activities had been developed from previous research findings and evaluated by three physics experts in teaching mechanics before using in a real classroom. Data collection included both qualitative and quantitative methods. Item analysis and whole-test analysis were determined from student responses in the conceptual test. As results, most students had misconceptions about restoring force and they had problems connecting mathematical solutions to real motions, especially phase angle. Moreover, they had problems with interpreting mechanical energy from graphs and diagrams of the motion. These results were used to develop effective instructional materials to enhance student abilities in understanding simple harmonic motion in term of multiple representations.

The purpose of this research was to develop students' concept of and retention rate in relation to energy conservation. Activities included simple and easy experiments that considered energy transformation from potential to kinetic energy. The participants were 30 purposively selected grade 10 students in the second semester of the 2016 academic year. The research tools consisted of learning lesson plans and a learning achievement test. Results showed that the experiments worked well and were appropriate as learning activities. The students' achievement scores significantly increased at the statistical level of 05, the students' retention rates were at a high level, and learning behaviour was at a good level. These simple experiments allowed students to learn to demonstrate to their peers and encouraged them to use familiar models to explain phenomena in daily life.

The purposes of this research were: to construct packages of operations on buoyancy and the involvement of Newton's third law, to enhance achievement score of students on buoyancy and the involvement of Newton's third law, to enhance experimental skills on buoyancy and the involvement of Newton's third law and to evaluate students' attitude towards the packages of operations on buoyancy and the involvement of Newton's third law using inquiry method. The samples were 42 grade 11 students in academic year 2016 at Hatyaiwittayalai School, Hatyai, Songkhla. The research method was one group pretest-posttest design. The research tools consisted of experimental set on buoyancy and the involvement of Newton's third law, the learning achievement test on buoyancy and the involvement of Newton's third law and the students' attitude questionnaires. The experimental skills of most students was in a good level . The satisfaction of most students was in a good level. The research showed the learning achievement after instruction higher than that before instruction using experimental set at the significant level of 0.05 and the class average normalized gain is in the medium gain

The determination of the energy values, specifically the heat of combustion of various M-16 black powders was the important part of the bullet efficiency investigations. The calorimetric bomb is commonly used for these determinations. Four M-16 black powders from the different sources were used as samples for this research. It was found that, after using calorimetric bomb technique, the gross heating value in Joules/g of sample S1-S4 were 10,647, 10,416, 5,281 and 3,878 respectively. The chemical compositions of carbon (C), hydrogen (H), nitrogen (N) and sulfer (S) have also been determined. The results indicated that carbon and nitrogen compositions of sample S1 shown the highest values and provided little differences with sample S2 while sample S3 and S4 shown the lowest carbon and nitrogen percentage composition. The hydrogen composition of all samples was equally valued, however, only sample 3 and 4 displayed sulfur values while no sulfur values were detected from sample 1 and 2. From these results, the heat values and chemical composition of M-16 black powders were characterized their sources and the energy values might be estimated from the amount of carbon and nitrogen in the black powders. Thus, it would be possible to use this determination analysis in the forensic investigation.

With and without physical context, we explored 59 undergraduate students'conceptual and procedural understanding of vector components using both open ended problems and multiple choice items designed based on research instruments used in physics education research. The results showed that a number of students produce errors and revealed alternative conceptions especially when asked to draw graphical form of vector components. It indicated that most of them did not develop a strong foundation of understanding in vector components and could not apply those concepts to such problems with physical context. Based on the findings, we designed a worksheet to enhance the students' conceptual understanding in vector components. The worksheet is composed of three parts which help students to construct their own understanding of definition, graphical form, and magnitude of vector components. To validate the worksheet, focus group discussions of 3 and 10 graduate students (science in-service teachers) had been conducted. The modified worksheet was then distributed to 41 grade 9 students in a science class. The students spent approximately 50 minutes to complete the worksheet. They sketched and measured vectors and its components and compared with the trigonometry ratio to condense the concepts of vector components. After completing the worksheet, their conceptual model had been verified. 83% of them constructed the correct model of vector components.

The scientists once believed an atom was the smallest particle, nothing was smaller than this tiny particle. Later, they discovered an atom which consists of protons, neutrons and electrons, and they believed that these particles cannot be broken into the smaller particles. According to advanced technology, the scientists have discovered these particles are consisted of a smaller particles. The new particles are called quarks leptons and bosons which we called fundamental particle. Atomic structure cannot be observed directly, so it is complicated for studying these particles. To help the students get more understanding of its properties, so the researcher develops the learning pattern of fundamental particles from Play Dough Model for high school to graduate students. Four step of learning are 1) to introduces the concept of the fundamental particles discovery 2) to play the Happy Families game by using fundamental particles cards 3) to design and make their particle in a way that reflects its properties 4) to represents their particles from Play Dough Model. After doing activities, the students had more conceptual understanding and better memorability on fundamental particles. In addition, the students gained collaborative working experience among their friends also.

Connecting physics concepts to activities that are interesting to students or what they encounter in everyday life will help students build a strong foundation. When there is an interesting activity for the student, it will result in the student responding, engaging, and enthusiasm in learning. Learning activities that are based on what students are interested in and regularly experience will enable students to understand the long and memorable experience. Both of these will enhance the student's learning experience. One of the activities that can be described in this research used the learning activity through movies, which is the application of the basic motion projectile for students to understand the characteristics of such movement. It also aims to further develop critical thinking skills of learners.

Thermoluminescence properties of Thai commercial window glass provided by Guardian Industries Corporation (denoted as WG) were studied. WG was doped with varying concentrations of ZnO. The composition of glass is 90WG-10Na₂O-xZnO (where x = 0.000, 0.001, 0.010, 0.100, 1.000 mol%). Glass samples were recycled by using melt quenching technique and cut into the dimensions of 6×6×1 mm³. After irradiated glass samples with X-ray at photon energy 160 keV in absorb dose rang 0-14 mGy, the glow curve structure, TL sensitivity, linearity and minimum detectable dose were investigated.

Titanium nitride (TiN) coatings have been used very successfully in a variety of applications because of their excellent properties, such as the high hardness meaning good wear resistance and also used for covering medical implants. Hydroxyapatite is a bioactive ceramic that contributes to the restoration of bone tissue, which together with titanium nitride may contribute to obtaining a superior composite in terms of mechanical and bone tissue interaction matters. This paper aims to explain how to optimize deposition conditions for films synthesis on PEEK by varying sputtering parameters such as nitrogen flow rate and direction, deposition time, d-s (target-to-substrate distance) and 13.56 MHz RF power. The plasma conditions used to deposit films were monitored by the optical emission spectroscopy (OES). Titanium nitride/Hydroxyapatite composite films were performed by gas mixture with nitrogen and argon ratio of 1:3 and target-to-substrate distance at 8 cm. The gold colour, as-deposited film was found on PEEK with high hardness and higher surface energy than uncoated PEEK. X-ray diffraction characterization study was carried to study the crystal structural properties of these composites.

This study was aimed at understanding elemental concentration distribution in local longan leaf for how the plant was affected by the environment or agricultural operation. The analysis applied the MeV-microbeam particle induced X-ray emission (PIXE) mapping technique using a home-developed tapered glass capillary microbeam system at Chiang Mai University. The microbeam was 2-MeV proton beam in 130 µm in diameter. The studying interest was in the difference in the elemental concentrations distributed between the leaf midrib and lamina areas. The micro proton beam analyzed the leaf sample across the leaf midrib edge to the leaf lamina area for total 9 data requisition spots. The resulting data were colored to form a 1D-map of the elemental concentration distribution. Seven dominant elements, Al, S, Cl, K, Ca, Sc and Fe, were identified, the first six of which were found having higher concentrations in the midrib area than in the lamina area, while the Fe concentration was in an opposite trend to that of the others.

In this paper, the efficiency of a HPGe detector for a PGNAA system has been determined using the full peak energy of a ¹⁵²Eu source. The efficiency is affected by the detector-source distance for the full energy range. The Monte Carlo method was used to determine the detector's dead layer thickness. A comparison of the simulated and the experimental data on the spectra and efficiency curve shows a very good agreement. The combined results of an experimental and calculation efficiency curve provide information about the dead layer thickness of 2.1 mm. It was found that the dead layer has the greatest effect on the detection efficiency of the low energy range.

The plasma focus is a device that uses high voltage and electromagnetic force to induce plasma generation and acceleration, in order to cause nuclear reactions. Radiation of various types (X-ray, gamma ray, electrons, ions, neutrons) can be generated using this method during the pinch phase, thus making the plasma focus able to serve as a radiation source. Material testing, modification, and identification are among the current applications of the plasma focus. Other than being an alternative option to isotopic sources, the plasma focus, which requires multidisciplinary team of personnel to design, operate, and troubleshoot, can also serve as an excellent learning device for physics and engineering students in the fields including, but not limited to, plasma physics, nuclear physics, electronics engineering, and mechanical engineering. This work describes the parameters and current status of Thai Plasma Focus 1 (TPF-1) and the characteristics of the plasma being produced in the machine using a Rogowski coil.

This research is designed to determine the efficacy of DBD plasma to reduce the microbial contamination of pepper and sesame powder. The AC high voltage power supply was used with voltages of up to 20 kV and the frequency of 5.5 kHz was applied to the DBD. The gap of DBD electrodes was set at 5 mm. In raw initial samples, the total aerobic count of pepper (Piper nigrum) was found at quite a high level at 5.40 × 10⁵ CFU/g. Coliform bacteria was also found in both the sesame (Sesamum indicum Linn.) powder and pepper (Piper nigrum) powder. Both kinds of samples were treated with plasma for 2, 4, 6 and 10 minutes. Results indicated that plasma treatment at 2-10 minutes reduced the total aerobic count of pepper allowed to achieve the acceptable microbial level for spices. The plasma treatment times in this experiment were also effective in reducing faecal coliform bacteria in both pepper and sesame powders (MPN/g <3) as indicated in the standard. Plasma from dielectric barrier charge can reduce Staphylococcus epidermidis in sesame powder which was artificially contaminated with 3.50 × 10² CFU/g resulting in 0.15-0.5 log cycle reductions of microbial load.

The specific activities of natural radionuclides (⁴⁰K, ²²⁶Ra and ²³²Th) in 50 surface beach sand samples collected from Bangsaen beach in Chonburi province in the easthern region of Thailand, were measured and evaluated. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system in the special laboratory at Thailand Institute of Nuclear Technology (Public Organization). The IAEA-SOIL-375 reference material was used to analyze the concentration of ⁴⁰K, ²²⁶Ra and ²³²Th in all samples. It was found that the specific activities of ⁴⁰K, ²²⁶Ra and ²³²Th were ranged from 510.85 - 771.35, 8.17 - 17.06 and 4.25 - 15.68 Bq/kg. Furthermore, frequency distribution of the specific activities were studied, analyzed and found to be the asymmetrical distribution by using a statistical computer program. Moreover, four radiological hazard indices for the investigated area were also calculated by using the median values of specific activities of ⁴⁰K, ²²⁶Ra and ²³²Th. The results were also compared with the Office of Atoms for Peace (OAP) annual report data, Thailand and global radioactivity measurement and evaluations.

The impact of pellet injection in International Thermonuclear Experimental Reactor (ITER) are investigated using integrated predictive modeling codes TASK/TR and HPI2 . In the core, the plasma profiles are predicted by the TASK/TR code in which the core transport models consist of a combination of the MMM95 anomalous transport model and NCLASS neoclassical transport. The pellet ablation in the plasma is described using neutral gas shielding (NGS) model with inclusion of the ∇B-induced $\overrightarrow{E}\times \overrightarrow{B}$ drift of the ionized ablated pellet particles. It is found that the high-field-side injection can deposit the pellet mass deeper than the injection from the low-field-side due to the advantage of the ∇B-induced drift. When pellets with deuterium-tritium mixing ratio of unity are launched with speed of 200 m/s, radius of 3 mm and injected at frequency of 2 Hz, the line average density and the plasma stored energy are increased by 80% and 25% respectively. The pellet material is mostly deposited at the normalized minor radius of 0.5 from the edge.

This research studies plasma performance in fusion Tokamak system by investigating parameters such as plasma pressure in the presence of an edge transport barrier (ETB) and an internal transport barrier (ITB) as the off-axis driven current position is varied. The plasma is modeled based on the bifurcation concept using a suppression function that can result in formation of transport barriers. In this model, thermal and particle transport equations, including both neoclassical and anomalous effects, are solved simultaneously in slab geometry. The neoclassical coefficients are assumed to be constant while the anomalous coefficients depend on gradients of local pressure and density. The suppression function, depending on flow shear and magnetic shear, is assumed to affect only on the anomalous channel. The flow shear can be calculated from the force balance equation, while the magnetic shear is calculated from the given plasma current. It is found that as the position of driven current peak is moved outwards from the plasma center, the central pressure is increased. But at some point it stars to decline, mostly when the driven current peak has reached the outer half of the plasma. The higher pressure value results from the combination of ETB and ITB formations. The drop in central pressure occurs because ITB stats to disappear.

The criteria for the L-H transition and ITB transition in fusion plasmas is studied based on the bifurcation concept. Three transport equations including thermal, particle and toroidal momentum density are solved simultaneously, resulting in the prediction of plasma pressure, plasma density and toroidal velocity profiles at steady state. The thermal and particle transport include both neoclassical and anomalous effects with the velocity shear dependent suppression effect. The results show that the flux (thermal/particle/momentum) versus gradient (pressure/density/velocity) space of each field independently exhibits s-curve bifurcation nature in which a forward L-H and ITB transitions require higher flux than that of the respective backward transitions, hence hysteresis behaviors. In addition, it is found that there exist certain regimes where the transitions are possible. In particular, the ratios of anomalous over neoclassical transport must exceed certain thresholds.

Atmospheric-pressure argon plasma (APAP) is a promising non-thermal technology for microbial control and prevention minimally affecting quality of foods. Effect of APAP jet on the growth of bread molds, including two Aspergillus sp., Rhizopus stolonifer, and Penicillium roqueforti, isolated from white bread were investigated. The molds were isolated, verified, cultured to fully grown on potato dextrose agar (PDA), and subsequently treated with APAP jet using plasma generating power at 24 W for 5, 10, and 20 min, respectively. The inhibition of mold growth was investigated by comparing fungal dry weights and the effect on fungal cell structure was observed using compound light microscope. The results indicated that the 20-min treatment time is most effective in retarding the growth of the three bread molds. However, this level of generating power did not lead to destruction of the cellular structures for all the four fungi. Plasma generating power and treatment time are significant parameters determining the success of bread mold decontamination and further investigation on real bread matrix is needed.

This research focuses on simulation of the radiation attenuation using a Monte Carlo program called GEANT4. In the simulation, properties and geometries of the shielding system including thickness and element of the shielding material can be varied. The radiation in gamma rays regime is considered to be emitted from a Cs-137 radioactive source. The number of gamma photons at specific energy of 661.7 keV is calculated to compare the ability of radiation attenuation for different shielding materials with variable thickness. In addition, the experimental investigation was performed for three materials, which are lead, aluminum and iron, by using a NaI(Tl) scintillation detector. Then, the XCOM database were calculated to compare the results with the simulation. Both XCOM and simulation data as well as the experimental results are agreed well to the theoretical suggestion. Consequently, the results from Monte Carlo simulation with program GEANT4 can be used to design the radiation shielding system for radioactive laboratories, particle accelerator institutes, radiotherapy area in hospitals, nuclear power plants, etc.

UNU/ICTP Plasma Focus Device has been used as an ions source in many applications. In this paper, the full dynamic range of argon ions produced by the Plasma Focus Device from its initial phase through to beyond the focussing phase of the plasma is shown experimentally. The average speed of the ions is determined by measuring time taken for ions to reach different positions using magnetic probes and ion probes. Also, by adapting a well-established computational model that represents the dynamics of plasma in such device, it is also possible to determine the speed of these ions up to the point where the movement of the plasma sheath under the Lorentz force is completed. However, it was found that the speed determined by the computational model is higher in comparison with the values obtained experimentally at all different operating pressures. The ions' speed found for operating pressure of 0.5 mbar, 1.0 mbar, 1.5 mbar and 2.0 mbar were 5.16 ± 0.04 cm/μs, 4.24 ± 0.04 cm/μs, 3.81 ± 0.03cm/μs and 3.16 ± 0.04 cm/μs respectively. These correspond to the ion energy of 551.38 ± 8.55 eV, 372.29 ± 7.02 eV, 300.61 ± 4.73 eV and 206.79 ± 5.24 eV.

A fusion plasma is one of misty plasmas, because it always mixes with droplets produced from tokamak wall erosion and melting of dust by plasma heating. It is unavoidable for droplets to interact with edge transport barrier (ETB) during their flights. ETB is the transition zone between edge and core plasmas, where the ETB plasma is hot and dense. Thus, impurity dust and droplets should barely penetrate into core plasmas. It is clearly that vaporization is a mechanism responding to the circumstance. However, its detail is needed to be studied. The paper proposes the mechanisms to produce the heavy and localized impurity deposition in tokamaks through vaporization by superheating in ETB. The preliminary results suggests that droplets can achieve superheating when they travels in ETB towards core plasmas where de-pressurization exists along the path. In addition, there is a zero liquid pressure in ETB as a cutoff where liquid droplet cannot be existed. This leads to electrostatic breakups and strong vaporization, both of which ensure that dust and droplets hardly penetrate to core plasmas.

We investigated quantum corrections to classical nuclear simulations of the π⁺(³He, ppn)π⁺ reactions. These simulations are often used to describe nuclear reactions which lead to many nal states. The ratio of the quantum multiple scattering to the classical cross section for the same process is used as a correction to the classical model calculation. The single, double, triple and all scatterings for the scattering protons of different angles are presented.

The purpose of this study was to evaluate the radionuclide concentrations of London blue topaz after fast neutron irradiation. The London blue topaz was obtained from Sri Lanka which classified into dark and light colors in the shape of an oval and rectangle with small, medium and large size. The optical property and radionuclide concentrations of London blue topaz have been examine by UV-Visible spectroscopy and HPGe gamma ray spectrometry, respectively. The UV-absorption spectra of topaz was taken in the range of 300 to 800 nm at room temperature. The results showed that the absorption peak of topaz was observed with only broad peaks in the range of 550 to 700 nm and 630 nm that correlated to the O - center in hydroxyl sites which substitutes for fluorine in topaz structure. The radioactivity of dark and light colors in the shape of an oval and rectangle London blue topaz was in the range of 1.437 ± 0.014 to 21.551 ± 0.037 nCi/g (oval dark), 2.958 ± 0.031 to 6.748 ± 0.054 nCi/g (oval light) and 2.350 ± 0.014 to 43.952 ± 0.088 nCi/g (rectangle dark), 1.442 ± 0.023 to 6.748 ± 0.054 nCi/g (rectangle light), respectively. The decay rates of ⁴⁶Sc, ¹⁸²Ta and ⁵⁴Mn isotopes created by irradiation showed that the decay time of the radioactive element depended on the size of the topaz so increased with decreasing the size of topaz. Moreover, the size of topaz also affect the absorption coefficient. This study is applied to predict time of residue dose of topaz for enhancement colorless topaz by neutron radiation treatment.

The Specific Activities of ⁴⁰K, ²²⁶Ra and ²³²Th were studied and determinate for 30 beach sand samples collected from Talo Kapo beach of Yaring district in Pattani province. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system. The IAEA-SOIL-6 reference materials obtained from the International Atomic Energy Agency were also used to analyze and compute the ⁴⁰K, ²²⁶Ra and ²³²Th specific activity in all 30 beach sand samples. The measuring time of each sample is 10,000 seconds. It was found that specific activity range from 1805.37 – 3323.05, 40.96 – 2137.36 38.63 – 4329.28 Bq/kg for with mean values of 2242.79 ± 117.40, 250.18 ± 8.21 and 458.42 ± 7.68 Bq/kg for ⁴⁰K, ²²⁶Ra and ²³²Th, respectively. Moreover, the results were also compared with research data in the south of Thailand, the Office of Atoms for Peace (OAP) annual report data and the recommended values which were proposed by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR,)

Fission product behaviors of Cs, a major element released in a severe nuclear accident, still remain unclear. The question frequently addressed is whether Cs released will be in the form of Cs₂MoO₄ or CsOH. This is a challenging issue since it has been demonstrated that the reaction between Cs₂MoO₄ and water leading to CsOH production is thermodynamically favored. The present research aims at investigation of CsOH generation through this chemical channel. A high-temperature setup with a flow system based on the cooling system of a water-cooled nuclear reactor has been assembled. The reaction between aqueous solutions of CsI and Na₂MoO₄ in a high-corrosion-resistant hot cell (Hastelloy) has been studied up to 80 °C in deoxygenated system. The products have been characterized using FTIR and XRD. The results have shown that there is no reaction between CsI and Na₂MoO₄ under the experimental conditions.

The measurement of moisture content in soil is based on the principle of neutron back scattering. In this principle, when fast neutrons emitted from a radioactive source collide with hydrogen atoms their energies are much greater reduced than colliding with other elements. The number of slowed down neutrons, hence, represents the number of hydrogen atoms present in the vicinity of the source. As water is the main contributor of hydrogen atoms in a soil medium, the moisture content in soil, therefore, can be measured based on this principle. An in-house developed probe containing a source of fast neutrons and a slow neutron detector was inserted into soil at different depths under the ground level. The probe was made of high density polyethylene and connected to a suitably calibrated detection system by a single cable. The moisture content was determined from the slow neutron count rate. The results of field measurement tests were reported and discussed.

The neutron imaging is a powerful non-destructive technique to investigate the internal structure and provides the information which is different from the conventional X-ray/Gamma radiography. By reconstruction of the obtained 2-dimentional (2D) images from the taken different angle around the specimen, the tomographic image can be obtained and it can provide the information in more detail. The neutron imaging system at Thai Research Reactor TRR-1/M1 of Thailand Institute of Nuclear Technology (Public Organization) has been developed to conduct the neutron tomography since 2014. The primary goal of this work is to serve the investigation of archeological samples, however, this technique can also be applied to various fields, such as investigation of industrial specimen and others. This research paper presents the performance study of a compact neutron camera manufactured by Neutron Optics such as speed and sensitivity. Furthermore, the 3-dimentional (3D) neutron image was successfully reconstructed at the developed neutron imaging system of TRR-1/M1.

The anti-reflective (AR) coatings were regarded as one of the promising options to improving the efficiency of light transmission in optical-based devices. In this work, we designed an ultra-high anti-reflective layer based on a 1D photonic crystal structure. By using the specific properties of the 1D photonic crystal on a particular filtering wavelength, a high transmission enhancement was achieved. The periodic stack of tantalum pentoxide (Ta2O₅) and molybdenum disulfide (MoS₂) in borosilicate glass (BK7) layers was modified with a graphene as a defect layer to investigate the effect of the modification on the optical transmission factor. The FDTD simulations showed an extremely 99.8255% transparency at the wavelength of 505.263 nm. The result was consistent with the analytical results obtained from a transfer matrix calculation. The proposed design can be applied to the coated narrow linewidth thin film as used for example in integrated optical systems.

Polymer solar cells is one of the promising technologies that gain tremendous attentions in the field of renewable energy. Optimization of thickness for each layer is an important factor determining the efficiency of the solar cells. In this work, the optimum thickness of Poly(3,4-ethylenedioxythione): poly(styrenesulfonate) (PEDOT:PSS), a famous polymer widely used as hole transporting layer in polymer solar cells, is determined through the analyzing of device's photovoltaic parameters, e.g. short circuit current density (J_sc), open circuit voltage (V_oc), fill factor (FF) as well as power conversion efficiency (PCE). The solar cells were prepared with multilayer of ITO/PEDOT:PSS/PCDTBT:PC₇₀BM/TiO_x/Al by rapid convective deposition. In such preparation technique, the thickness of the thin film is controlled by the deposition speed. The faster deposition speed is used, the thicker film is obtained. Furthermore, double layer deposition of PEDOT:PSS was introduced as an approach to improve solar cell efficiency. The results obviously reveal that, with the increase of PEDOT:PSS thickness, the increments of J_sc and FF play the important role to improve PCE from 3.21% to 4.03%. Interestingly, using double layer deposition of PEDOT:PSS shows the ability to enhance the performance of the solar cells to 6.12% under simulated AM 1.5G illumination of 100 mW/cm².

Silicon-based photonics has generated a strong interest in recent years, mainly for optical interconnects and sensing on photonic integrated circuits. The main rationales of silicon photonics are the reduction of energy consumption and photonic system costs via integration on a standard Si chip. Waveguide-integrated silicon based-optoelectronic modulators have been particularly studied as a key building block. Ge-rich Ge/SiGe quantum well waveguides are promising for compact and low energy consumption modulators thanks to the demonstration of direct gap related optical transitions in these structures, while silicon nitride (SiN) waveguide could be a promising alternative to Si waveguide. This paper studies an integration approach between passive SiN waveguide and active Ge/SiGe multiple quantum wells (MQWs) optoelectronic modulators. Photocurrent measurements at different bias voltages demonstrated strong optical modulation within the O-band wavelength (1.26 – 1.36 µm) from Ge/SiGe MQWs, while 3D-FDTD calculations confirm a compact and efficient integration with SiN waveguide on Si wafer.

Aluminum doped Zinc Oxide (AZO) nanoparticle thin films were deposited on glass substrates by a double tip sparking process. The effect of Al doped ZnO on electrical and optical transmittance properties were studied. The doping ratios of Al into ZnO were 3, 5, 7, 13 and 22 %. SEM images indicated particle size decreased with increasing the Al content after annealing. Raman spectra results of AZO films associated with the hexagonal structure. AZO films have an average transmittance in visible region at 60 %. The energy gap increased with increasing Al content. The minimum resistivity was found at 5 % of Al doping for AZO film.

Candle soot containing carbon nanoparticles can form hierarchical structure films. We prepared soot films by using glass slides blocking candle flame in the middle of the flame. The hierarchical nanostructures of the carbon nanoparticles films were confirmed by scanning electron microscopy and transmission electron microscopy. Carbon nanoparticle size was 49.2 ± 9.0 nm from SEM, which agrees to 37.9 ± 8.5 nm from TEM. The contact angles of water droplets on these films are more than 150°, indicating superhydrophobic surface. Decrease contact angles of water droplets were observed with an increase deposition time. The decrease of contact angle was saturated at about 150° when the deposition time reaches 180 s. Cassie-Baxter state was attributed to describe superhydrophobicity of carbon nanoparticles films because the hierarchical nanostructures of the surface provide a large fraction of hollows on the surface. We proposed that the contact angle dependence on deposition time was governed by the increase of the distance between nanopillars in carbon nanoparticles films.

We have fabricated dye sensitized solar cells and improved their efficiency. The working electrodes were made of Al-doped and Cu-doped TiO₂ nanotubes by anodization process. We also prepared 2 polymers: the poly acrylonitrile-co-styrene and polyethylene oxide to compare efficiency of these polymer electrolytes. X-ray diffraction (XRD) was used to study the microstructure of the titania nanotubes, scanning electron microscopy (SEM) was used to study structural morphology, and UV-visible spectroscopy optical property was employed to determine the optical property. The effect of Al-doping and Cu-doping on the efficiency of the solar cells was investigated. The conversion efficiencies of poly (acrylonitrile-co-styrene), Poly(ethylene oxide), Al-doped TiO₂ and Cu-doped TiO₂ were 0.184, 0.121, 0.008 and 0.169 respectively for irradiation of 800 W/m².

The irradiation is one of the gemstone enhancements for improving the gem quality. Typically, there are many varieties of irradiated gemstones in the gem market such as diamond, topaz, and sapphire. However, it is hard to identify the gemstones before and after irradiation. The aim of this study is to analyze the surface morphology for classifying the pristine and irradiated sapphires using atomic force microscope (AFM). In this study, the sapphire samples were collected from Phrae Province, Thailand. The samples were irradiated by high energy electron beam for a dose of ionizing radiation at 40,000 kGy. As the results, the surface morphology of pristine sapphires shows regular atomic arrangement, whereas, the surface morphology of irradiated sapphires shows the nano-channel observed by the 2D and 3D AFM images. The atomic step height and root mean square roughness have changed after irradiation due to the micro-structural defect on the sapphire surface. Therefore, this study is a frontier application for sapphire identification before and after irradiation.

The Co₇₅Ag₂₅ films were deposited on Co, Ni, Cr and Al under-layers and polyimide substrate by RF-sputtering. All of films exhibited soft perpendicular anisotropy with Co-HCP (220) and Ag-FCC (111) and (200) structures. The Co₇₅Ag₂₅ film on Co under-layer showed regular grain distribution and maximum grain size of about 32 nm whereas the film on Ni under-layer showed minimum grain size and surface roughness of about 9.8 and 1.3 nm, respectively. The film deposited on Cr under-layer showed maximum perpendicular coercivity and highest squareness ratio about 181 G and 0.112, respectively while the film on Co under-layer showed maximum saturation and remanent magnetization in both of parallel and perpendicular measurements. All results imply that magnetic properties and surface roughness and morphology of sputtered Co₇₅Ag₂₅ films are dependent on under-layer gran size and distribution.

Sputtered Co₈₁Pd₁₉ films with thickness of about 60 nm were deposited on various under-layers (Co, Ni, Cr and Al) and on glass substrate. Structural, morphological and magnetic properties of Co₈₁Pd₁₉ films were investigated. All of prepared Co₈₁Pd₁₉ film showed CoPd-FCC phase in (111) direction on CoO-FCC (111), NiO-FCC (200), Cr-BCC (200) and (201) and AlO-FCC (200) phases of Co, Ni, Cr and Al under-layer, respectively. AFM images revealed that the film on Cr under-layers and glass substrate exhibited the maximum roughness with the highest grain size and the minimum roughness with the continuous grain size, respectively. Both parallel and perpendicular maximum coercive field were found in the film on glass under-layer and the film on Co-under-layer film showed the highest saturation magnetization from both in-plane and out-of-plane measurements. These results confirmed that the structural and magnetic properties of sputtered Co₈₁Pd₁₉ films were affected by under-layer surface roughness and morphology by the virtue of particle size and distribution on the under-layer film surface.

The vacuum vaporization technique is widely used to develop of visualized latent fingerprints on substrate surface for forensics investigation. In this study, we reported the first utilization of lawsone in the vacuum vaporization technique. The lawsone was sublimation in vacuum and showed the detected latent fingerprints on thermal papers. The method involves hanging the thermal paper samples 5, 10, 15 cm above a heating source with dispersed lawsone solids in a vacuum chamber. The optimized condition for lawsone sublimation are 50, 100, 150 mg with low-vacuum (0.1 mbar) and vaporizing temperature at 40-60°C. The sample fingerprints were left for 1, 3, 7 and 30 days before examination comparison between lawsone and fingerprint ink pad using an Automated Fingerprint Identification (AFIS). The resulted showed that using 100 mg lawsone sublimation on thermal paper at the range of 10 cm evidenced the clear, detectable minutiae which can be used for visualization and identification of latent prints without the background black staining known. Thus, this study might be interested application for developing latent fingerprints as a solvent free technique and non-hazardous materials.

The effect of various annealing treatments on the structure properties of crystalline silicon (c-Si) produced by the inverted aluminium induced crystallization of amorphous silicon (a-Si) films was studied. The surface morphology and grain size of c-Si films were observed by optical microscope and scanning electron microscope. X-ray diffraction and Raman spectroscopy were used to study quantity of Si crystallization due to thermal annealing. Results showed that the c-Si with an average grain size of 54 nm in a (111) orientation was obtained by the thermal annealing at 350 °C for 1 h. Prolonged heat treatment improved Si crystallite quality and increased the average grain size.

A TiO₂ compact layer or blocking layer plays a crucial role in a hybrid organic-inorganic lead halide perovskite solar cell because it can prevent the carrier recombination at the interface of fluorine-doped tin oxide (FTO) and perovskite layers. There are several methods to fabricate this layer such as spray pyrolysis or spin-coating which is solution-based synthesis that is difficult to avoid pinholes in the surface of the blocking layer. In this work, TiO₂ blocking layers are fabricated by radio-frequency (RF) magnetron sputtering using Ti metallic target with O₂ partial pressure in Ar atmosphere on FTO coated glasses. The controlled parameters for the deposition of TiO₂ compact layer are RF power, O₂ partial pressure, and deposition time. The optimization of the TiO₂ compact layers are found from the diode I-V characteristics between the TiO₂/FTO interfaces. The resistance between the TiO₂/FTO interfaces deviates from an ohmic contact towards a diode behavior when the thickness of TiO₂ is increased. The thickness of the films is directly measured by surface profilometer. In addition, the UV-VIS-NIR spectroscopy is used to observe the optical transmission of the films.

This article provides an approach to improve and control crystal phases of the sputtering vanadium oxide (V_xO_y) thin films by post-thermal annealing process. Usually, as-deposited V_xO_y thin films at room temperature are amorphous phase: post-thermal annealing processes (400 °C, 2 hrs) under the various nitrogen (N₂) pressures are applied to improve and control the crystal phase of V_xO_y thin films. The crystallinity of V_xO_y thin films changes from amorphous to α-V₂O₅ phase or V₉O₁₇ polycrystalline, which depend on the pressure of N₂ carrier during annealing process. Moreover, the electrical resistivity of the V_xO_y thin films decrease from 10⁵ Ω cm (amorphous) to 6×10^-1 Ω cm (V₉O₁₇). Base on the results, our study show a simply method to improve and control phase formation of V_xO_y thin films_.

In this work, highly transparent and highly conductive thin films of Al-doped ZnO (AZO) are achieved by pulsed laser deposition (PLD). By changing substrate temperature in the range of room temperature to 500°C during the deposition process, the preferential growth direction of AZO crystal is controlled and, therefore, the surface morphology, optical and electrical properties of AZO thin films are able to be manipulated. X-ray diffractograms as a function of the substrate temperature clearly illustrate the ability to control the preferential growth direction of AZO. At the low substrate temperature, the growth along [002] direction corresponding to c-axis of hexagonal ZnO is only observed. By elevating the substrate temperature, not only crystallinity of AZO thin film is further improved but also the competition of crystal growth along the [002], [001] and [101] directions are occurred due to the increase of total energy and surface mobility of cluster/atom. The AZO films obtained by all preparation conditions exhibit an n-type semiconducting characteristics, furthermore, the carrier concentration and the carrier mobility of AZO thin films can be optimized to reach 4.10×10²⁰ cm^-3 and 7.53 cm²/Vs, respectively. The excellences in both carrier concentration and mobility of AZO thin film lead to very low resistivity of 2.08×10^-3 Ωcm. In addition, the wide optical band gap of ∼3.50 eV together with the high transparency over 90% in visible region is obtained from the AZO thin films. The exceptional optical and electrical properties of AZO thin film demonstrate that such material has enough potential to become a promising candidate using in optoelectronic applications.

Alumina, such as glazed alumina for electrical insulator, operated in an open field subjects to a very harsh condition; resulting in lifetime shortening. Coating hydrophobic layer on alumina surface can help prolonging its lifetime. In this study, 25 ×25 mm alumina sheets were used as substrates. The hydrophobic composite polymers were prepared from (3-mercaptopropyl)trimethoxysilane(MPTMS), 2,4,6,8-tetramethyl-2,4,6,8tetravinylcyclotetra siloxane(TMTVSi), pentaerythritoltetra(3-mercaptopropionate)(PETMP), 2,2-dimethoxy-2-phe nylaceto phenone(photoinitiator) and heptadecafluorodecylmethacrylate(HEFDMA) via the thiol-ene reaction. The alumina sheets were first activated by dielectric-barrier discharge plasma to improve its adhesion. All the polymers were found to optimize at the ratio of (MPTMS:TMTVSi:PETMP:HDFDMA) to 4:2:1:2 for coating on the alumina substrate. To enhance polymerization, 2,2-dimethoxy-2-phenylaceto phenome was also used as a photoinitiator A proper mixing sequence in the thiol-ene reaction results in film with excellent surface retention after prolong soaking in solvent such as acetone. FTIR shows that S-H and C=C functional groups have significantly changed after photopolymerization and thermally cured. The static contact angle increase from mere 53.0°±1.5° of the uncoated substrate to 120.0°±1.2° after coating. SEM shows the film with clear appearance of a few-micron thick. Under AFM, the coated surface roughness was about 9.3 nm with evenly distributed spikes of a few nanometer in height. The cross-cut test also confirmed the film was very smooth and none of the square of the films detached.

The aim of this work was to study the effect of preparational factors such as solvent type, evaporation time (ET) and non-solvent additive, on the morphological structure, physical and gas separation properties of the prepared membrane samples by tuning of these parameters. Flat sheet asymmetric polysulfone (PSF) membranes were prepared by the dry/wet phase inversion process combined with the double coagulation bath method. The alteration of the prepared membranes were analyzed through scientific techniques such as Scanning Electron Microscope (SEM) and Dynamic Mechanical Thermal Analysis (DMTA). Furthermore, gas separation performance of membrane samples was measured in term of gas permeation and ideal selectivity of CO₂/CH₄. Experimental results showed that the change of preparational factors affected to the gas permeation of asymmetric PSF membranes. For example, the selective layer thickness increased with increasing of ET. This lead to increase significantly of ideal selectivity of CO₂/CH₄. The CO₂/CH₄ ideal selectivity was also increased with increase of ethanol (non-solvent additive) concentration in casting solution. In summary, the tuning of preparational factors affected to morphological structure, physical and gas separation properties of PSF membranes.

Stacks pattern of microspheres and nanoparticles can be deposited by layer-by-layer coating with several techniques. In this work, we fabricated two pattern monolayers of polystyrene microparticle by convective horizontal deposition. For initial layer, glass substrate was dragged with velocity of 25 μm/s and also applied horizontal vibration with frequency of 50 Hz in order to supply higher kinetic energy for better assembly. Sizes of polystyrene microparticles were 3.2 micrometer for this initial template coating. For the second layer, the microparticle size was varied with 0.93, 1.00, and 1.50 micrometer. The packing of the second layer was investigated by scanning electron microscope. The filling quality of second coating layer strongly depend on particle size and dragging velocity. For the same dragging speed, the microparticle of 0.93 micrometer trended to be well arrangement on the initial template with honeycomb pattern.

The multiplicative Hamiltonian flow on the phase space for a system with 1 degree of freedom was constituted from infinite hierarchy Hamiltonian flows. A new type of canonical transformation associated with the multiplicative Hamiltonian was found and called the λ-extended class of the standard canonical transformations.

The ground state entanglement of the system, both in discrete-time and continuous-time cases, is quantified through the linear entropy. The result shows that the entanglement increases as the interaction between the particles increases in both time scales. It is also found that the strength of the harmonic potential affects the formation rate of the entanglement of the system. The different feature of the entanglement between continuous-time and discrete-time scales is that, for discrete-time entanglement, there is a cut-off condition. This condition implies that the system can never be in a maximally entangled state.

In this work, the disease spreading under SIR framework (susceptible-infected-recovered) agent-based model was investigated via magnetic spin model, stochastic Monte Carlo simulation, and Neural Network analysis. The defined systems were two-dimensional lattice-like, where the spins (representing susceptible, infected, and recovered agents) were allocated on lattice cells. The lattice size, spin density, and infectious period were varied to observe its influence on disease spreading period. In the simulation, each spin was randomly allocated on the lattice and interacted with its first neighbouring spins for disease spreading. The subgroup magnetization profiles were recorded. From the results, numbers of agents in each subgroup as a function of time was found to depend on all considered parameters. Specifically, the disease spreading period slightly increases with increasing system size, decreases with increasing spin density, and exponentially decays with increasing infectious period. Due to many degrees of freedom associated, Neural Network was used to establish complex relationship among parameters. Multi-layer perceptron was considered, where optimized network architecture of 3-19-15-1 was found. Good agreement between predicted and actual outputs was evident. This confirms the validity of using Neural Network as supplements in modelling SIR disease spreading and provides profound database for future deployment.

In this work, the stock-price versus economic-field hysteresis was investigated. The Ising spin Hamiltonian was utilized as the level of 'disagreement' in describing investors' behaviour. The Ising spin directions were referred to an investor's intention to perform his action on trading his stock. The periodic economic variation was also considered via the external economic-field in the Ising model. The stochastic Monte Carlo simulation was performed on Ising spins, where the steady-state excess demand and supply as well as the stock-price were extracted via the magnetization. From the results, the economic-field parameters and market temperature were found to have significant effect on the dynamic magnetization and stock-price behaviour. Specifically, the hysteresis changes from asymmetric to symmetric loops with increasing market temperature and economic-field strength. However, the hysteresis changes from symmetric to asymmetric loops with increasing the economic-field frequency, when either temperature or economic-field strength is large enough, and returns to symmetric shape at very high frequencies. This suggests competitive effects among field and temperature factors on the hysteresis characteristic, implying multi-dimensional complicated non-trivial relationship among inputs-outputs. As is seen, the results reported (over extensive range) can be used as basis/guideline for further analysis/quantifying how economic-field and market-temperature affect the stock-price distribution on the course of economic cycle.

We used density functional theory (DFT) based on generalized gradient approximation (GGA) and hybrid functional (HSE06) to investigate band gap and structural stability of Al₂C monolayer and nanotubes. From the results, both GGA and HSE06 band gaps of Al₂C monolayer agree well with previously reported data. For the Al₂C nanotubes, we found that their band gaps are more sensitive to the size and the chirality than that of the widely studied SiC₂ nanotubes, indicating the Al₂C nanotubes may have higher band gap tuning capabilities (with varying diameter size and chirality) compared with those of SiC₂ nanotubes. We have also discovered a desirable direct band gap in the case of (n,0) nanotubes, although Al₂C monolayer band gap is indirect. The calculated strain energy reveals that (n,0) nanotubes constructed by wrapping up Al₂C monolayer consume less energy than (0,n) nanotubes. Thus, (n,0) nanotubes is easier to synthesize than (0,n) nanotubes. This discovery of direct band gap in (n,0) Al₂C nanotubes and their adjustable band gap suggests them as promising sensitizer for enhancing power conversion efficiency of excitonic solar cells.

This work reports the structures and electronic properties of two-dimensional (2D) ZnO in hexagonal, (4,8)-tetragonal, and (4,4)-tetragonal monolayer using GGA and HSE-hybrid functional. The calculated results show that the band gaps of 2D ZnO sheets are wider than those of the bulk ZnO. The hexagonal and (4,8)-tetragonal phases yield direct band gaps, which are 4.20 eV, and 4.59 eV respectively, while the (4,4)-tetragonal structure has an indirect band gap of 3.02 eV. The shrunken Zn-O bond lengths in the hexagonal and (4,8)-tetragonal indicate that they become more ionic in comparison with the bulk ZnO. In addition, the hexagonal ZnO sheet is the most energetically favourable. The total energy differences of (4,8)-tetragonal and (4,4)-tetragonal sheets from that of hexagonal monolayer (per formula unit) are 197 meV and 318 meV respectively.

An alternative way of finding the LTI's solution with the Born approximation, is investigated. We use Born approximation in the LTI and in the transformed LTI in form of Helmholtz equation. General solution are considered as infinite series or Feynman graph. Slow-roll approximation are explored. Transforming the LTI system into Helmholtz equation, approximated general solution can be found for any given forms of force with its initial value.