Table of contents

Preface

The 9^th TSME International Conference on Mechanical Engineering (TSME-ICoME 2018) was organized by the Department of Mechanical Engineering, Faculty of Engineering, Thammasat University, Phathumthani province, Thailand. The conference's venue was located at Tavorn Palm Beach Resort in Phuket and held from 11 to 14 December 2018.

Like other years the conference, being supported by Thai Society of Mechanical Engineering (TSME), is considered as a platform for innovators, researchers and industrial representatives around the world to discuss, collaborate and share ideas regarding mechanical-related topics of the century. For instance, the academic program included topics such as Alternative Energy and Combustion (AEC), Automotive, Aerospace and Marine Engineering (AME), Applied Mechanics, Materials and Manufacturing (AMM), Biomechanics and Bioengineering (BME), Computation and Simulation Techniques (CST), Dynamic Systems, Robotics and Controls (DRC), Energy Technology and Management (ETM), and Thermal System and Fluid Mechanics (TSF).

A total of 180 delegates from around the world including, Germany, Japan, Malaysia, Taiwan Slovakia, United States of America and Vietnam, contributed to initiate development of manufacturing technique, prototype machine, and automotive innovations. This volume of IOP Conference Series: Material Science and Engineering included 66 chosen papers whose authors presented at the conference. The aim of this publication is to inspire and spread novel ideas in the area of mechanical engineering.

Thermochemical Energy Storage for Utilization of Unused Heat and Engineering Innovative Practice in Engineering Education: in case study of Rehabilitative and Assistive Innovation, Abstract, Biography and Invited speakers are available in this PDF.

List of Conference Program Committee and Host and Organizing Committee are available in this PDF.

List of sponserships are available in this PDF.

List of Conference Photographs are available in this PDF.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering 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 study deals with the development of controlled-ignition technology for high performance compression ignition alcohol engines. Among the alcohol fuels, we focused on Ethanol as a promising candidate of alternative fuels replacing from petroleum. In our previous study, visualization tests of spray mixture formation process up to auto-ignition for Ethanol-Diethyl either blend fuels had been conducted by using a constant volume electrical heating combustion chamber. Quantitative evaluation of auto-ignition quality was summarized in a form of 3D map that indicates the effects of surrounding gas pressure, temperature and Oxygen concentration on ignition delay. However, maximum surrounding gas pressure in the experiments was 2.8MPa much less than that of real engine due to the structure of the combustion chamber. As the next step, we originally designed and manufactured a RCEM (Rapid Compression and Expansion Machine with variable compression ratio) in order to investigate the mixture formation process up to auto-ignition of an Ethanol spray under surrounding gas conditions similar to real engine operating conditions with the consideration of the interaction between fluid motion of surrounding gas and fuel injection. Prior to carrying out the experiments, we numerically predicted the auto-ignition quality of an Ethanol spray in the rapid compression and expansion machine. One of the commercial CFD codes; CONVERGE was used in the computational calculation with the considerations of turbulence, atomization, evaporation and detailed chemical reaction. Effect of fluid motion and surrounding gas pressure and temperature inside the combustion chamber of the RCEM on an Ethanol spray mixture formation is mainly discussed in this paper.

The pressure to diversify the raw material base of solid biofuels is steadily rising worldwide. The waste from agricultural production and its post-processing represents a huge but still little used energy potential. The use of such plant waste brings many technical problems. The paper is focused on research of increasing physical, mechanical and thermal quality indicators of composite pellets based on a mixture of sunflower husks and spruce sawdust. Tested mixtures varied by increasing the weight proportion of wood sawdust from 0% up to 40% in sunflower husks. The quality of this fuel pellets was evaluated using standardized parameters - particular density, bulk density, pellet moisture, mechanical durability, pellet hardness, calorific value, ash content etc.. Realized experiments have shown that it is not only possible to successfully transform this homogenized mixture into fuel pellets (pure sunflower husks represent a considerable problem with densification regard to their composition), but the qualitative parameters of the fuel also increase by increasing the weight proportion of wood in sunflower husks. The research results showed that the optimum ratio of wood component in the composite fuel is 30% based on the resulting mechanical quality parameters and economy of its production.

The major problem of biohythane production from palm oil mill effluent is the high carbon dioxide (CO₂) content. In this study, an innovative water scrubber system for upgrading biohythane has been experimentally investigated. Biohythane composing of ∼53.34% of CH4, ∼39.12% of CO₂, and ∼7.54% of H2 was simulated regarding the composition of biohythane in the lab scale. Response surface methodology (RSM); a 5-level, 3-factor, central composite design (CCD), was employed to optimize three important parameters (biohythane flow-rate, water flow-rate, and operating time) in order to minimize the CO₂ content in the biohythane production. As a result, CO₂ concentration decreased with the increase of both the operating time and water flow-rate but inversely proportion to the biohythane flow-rate, which led to higher CO₂ absorption by water. The optimal condition regarding the maximum value of CO₂ reduction was found at: 3 Nl/min of biohythane flow-rate, 16 Nl/min of water flow-rate, and 9 min of operating time, thereby yielding 77.6% of CO₂ reduction.

The mutual interaction between pellets quality, which is represented by the pellets physical properties, and the input composition of raw material is very interesting and complicated itself. Therefore, the main aim of this research paper is to determine the relationship between the raw material composition, which influences the pellets quality and the pellets quality indicators - physical properties of pellets. During the biomass densification, also the raw material properties significantly influence the final solid biofuels quality. Therefore the raw material composition represented by different mixtures from spruce sawdust, wheat straw and spruce bark, in various ratios (90/10, 80/20, 50/50, 80/10/10 and 50/30/20) and in various raw material composition (sawdust/straw, straw/bark, straw/sawdust/bark) were investigated. During this research study in total 14 different material composition was used. Effect of mentioned raw material mixtures on pellets bulk density, mechanical durability, abrasion, particle density and hardness were determined. Research findings presented in this paper are based on a realized experimental research that was done on Faculty of Mechanical Engineering STU in Bratislava. This experimental research was a logical result of and based on authors practical experience and wide theoretical analyses of selected variables influence. Described experimental research was realized by real pelleting machine that is a part of semi-production pelleting plant on Faculty of Mechanical Engineering STU in Bratislava. The experimental findings presented here are showing the importance of mentioned variables and parameters during the pelletizing process.

So far, a method of employing ultrasound irradiation and zeolites as solid catalyst for BDF synthesis has been suggested and experimentally verified. However, since catalyst poisoning will occur due to the repeated use of the same zeolite for BDF synthesis, hence at current paper, the catalyst poisoning characteristics of zeolite was investigated as the study target. During the study, firstly several zeolites of were selected and prepared to increase their basic characteristics. Secondly, the basic characteristics of the prepared zeolites were characterized by using SEM and X-ray diffractometer. Thirdly, BDF synthesis experiment was carried out by using the selected zeolite based on ultrasonic irradiation for several times. It was found that BDF yield ratio decreased as the number of the BDF synthesis experiments repeated while the same catalyst was used.

This paper presents comparison for the thermal efficiency between a parabola greenhouse solar dryer and sinusoidal greenhouse solar dryer by computational fluid dynamics (CFD). The concept of design is to find ways to increase the solar area of the greenhouse solar drying. The greenhouse solar dryers used in the analysis are 2 types: 1) parabola greenhouse dryer has a one side solar roof structure for received solar energy area of 95.47 m² and 2) new design greenhouse is a sinusoidal greenhouse dryer has a two-sided solar roof structure for received solar energy area of 96.63 m², which increases the solar receiving area of 1.22%. The both volume of greenhouse dryers was about 94 m³ (a parabola greenhouse dryer is a standard plant greenhouse dryer from department of alternative energy department and efficiency, Ministry of Energy, Thailand. The size: 8.2 of length and 6.0 of wide). The greenhouse dryer were received an average heat flux from the solar of 1,000 W/m² at 11.00am. - 02.00pm. in Udon Thani province, Thailand (in the absence of cloud cover) and the outside temperature is 28 °C. This experiment is an analysis of the effects of 6 hours of solar radiation at the same time for both greenhouse dryers to compare the temperatures using the computational fluid dynamic (CFD) program. The raw materials are drying at higher temperatures can be faster drying rate that resulting to drying time period is lower. From the results of the simulation, it was found that the average drying temperature of 6 hours for the sinusoidal and the parabola greenhouse is 322.26K (49.11°C) and 321.20K (48.05°C), respectively. The time of drying value of the sinusoidal greenhouse solar dryer is 3.40 hours at an average temperature value of 322.26K (49.11°C) and the parabola greenhouse solar dryer is 4.70 hours at an average temperature value of and 321.20K (48.05°C). In conclusion, a sinusoidal greenhouse has higher average drying temperatures with compared to a parabola greenhouse for the same drying time period. The sinusoidal greenhouse drying period takes less than the parabola greenhouse and higher drying efficiency.

Solid oxide fuel cells convert chemical energy in electrical energy and are highly suitable for the conversion of hydrocarbon based fuels and products from PowerToGas conversions. Embedded in a micro gas turbine-cycle instead of the combustion chamber the heat energy of the injected fuel, released in the SOFC-Stack, can additionally converted into work and by a turbine-generator into electricity. In a compact system, SOFC stacks are designed to realize a direct steam-reforming process inside. In such direct-reforming fuel cell systems the SOFC operating temperature due to the heat demand for reforming, can be reduced to a value in the range of the outlet temperature of the downstream flow (650°C). If the cycle uses a recuperating system, the operating conditions of the SOFC can be realized without additional high-temperature heat exchanger systems. The system with an uncooled turbine, described in [1], just can reach the operating temperature with an additional high-temperature heat exchange. The system described in this publication does not require an additional high-temperature heat exchanger, because the X-value, as the ratio between the exchanged heat quantity and the required amount of heat to complete the MGT-cycle [2] due to the referring process, is nearly zero and can be realized via the inner container wall (of the MLC). The cycle is completed (between the SOFC and the turbine entry) by the heat input of an afterburner. Here the unreacted fuel of the SOFC fuel-stream is used to provide the necessary heat energy for the downstream turbo-generator-system.

Compaction technologies have been known for over 130 years. Among the best-known compaction technologies are included briquetting, pelleting and compacting. The end products of such technologies are briquettes, pellets and granules. Recent times have seen a worldwide "boom" in the use of these refinings, especially with regard to pellets.

One great advantage of pellets in comparison with classic fuels is that according to need the three decisive parameters 'shape, size and density' of the resultant fuel can be changed during production. This leads to an optimization of costs for their production and storage and transportation requirements, but most of all, prerequisites in terms of optimal energy recovery.

One of the most discussed issues in the production of refined biofuels is the shape and size of the refined fuel. The quadrangle, n-angle or cylinder do not have optimal shapes from the point of view of automated transport in the fuel combustion process. From this standpoint the ball is the optimal shape, but it is not possible to create such pressings in a continuous process and present-day pressing and compacting machines lack a "fuel life" phase under pressure with simultaneous cooling. The endurance and cooling process has of course a great influence on the stability of the fuel produced.

The goal of the submitted paper is the development, design and testing of a new, patent-protected compacting machine construction which will allow the production of pressings biofuels of an almost circular shape. In contrast with readily available compacting - compression machines, such a compactor also provides cooling of the pressings under high pressure.

Road traffic fatalities involving powered-two wheeler (PTW) are the highest portion in Thailand. Few studies are available concerning the head impact loading and head trauma in case of real PTW accidents. This work, therefore, aims to improve the understanding on kinematics and head trauma of PTWs rider and pillion passengers. By selecting a real-world PTW accident provided by the Central Institute of Forensics Science database, reconstruction of the accident was performed using multibody dynamics simulations. Parametric studies which focused on vehicle speed and position of rider and passenger at impact was conducted to obtain the best correlations. Then, head impact velocity, impact direction and head impact area have been extracted and implemented in the finite element head model to simulate the head trauma by impacting directly the head model on the vehicle structure. The motorcyclist's head and the pillion passenger's head impact conditions were retrieved and used as initial condition for the finite element head impact simulation. Head and brain injuries were analyzed.

This paper reports consideration of efficient design method for the azimuthal-attitude control of stratospheric balloon gondolas utilizing only a motorized pivot. To maintain sufficient robustness against variation of the model parameters, applying of sliding mode controller is tried and proposed control system is validated by numerical simulation studies.

The purpose of this research is to study and design a concept of the tactical solar power UAV. The mission requirements derived from military applications: Intelligence, Surveillance, and Reconnaissance) ISR (which including a longer operation time) 8 hours (, 350-1000 meters service ceiling, and less than 5 kg for take-off weight. This paper, a conceptual design of solar power UAV mainly based on Noth's methodology. A simple program coding created for sizing solar power UAV by using Scilab. In addition, the vortex lattice method) XFLR5 program (also employed to evaluate the basic aerodynamic characteristics for three different low-Reynolds number airfoils. The wing incident angle was then designed. From the conceptual design results, the coding indicated that the solar power UAV is the conventional type of aircraft, which is provided 4 meters in wingspan (Aspect ratio 13 (, 3.88 kg for take-off weight, and 69.13% for solar area to wing area ratio.

Engine controller is a component that determines the engine running smoothly. With low cost, the Automated Spark Ignition Timing Controller (ASITC) can be design for the suitability of the study. The ASITC is to control spark ignition. For this purpose, Arduino microcontroller is used. It is equipped with potentiometer and 1.8 in TFT display. Through ignition timing, a misfire condition and knocking is actuate by advance spark. Instrustar DAQ is used to record data from spark ignition, oxygen sensor and knocking sensor. From the data obtained, signal processing will be done to get the desired feature through the filtering process. This paper is to study the ASITC to be made for specific features as needed.

The automotive windshield, with which pedestrians come into frequent contact during car accidents, has been identified as one of the main sources for severe pedestrian head injuries. Finite element simulation of head-to-windshield is widely used for the design and evaluation of car safety performance. Most of the windshield models used in the simulations for pedestrian head injury studies are simplified model. However, accurate modelling of windshield mechanical behaviour is necessary for good prediction of head injury during car-to-pedestrian collision. The purpose of this paper is to improve the model of automobile windshield for simulation of a collision between a pedestrian and a car. The laminated glass windshields of various thickness were tested according to UNECE R43. The deformation and crack pattern were recorded for validation of the finite element model. The finite element models of two layers and three layers laminate glass were developed. Element deletion method and share node techniques were employed for crack propagation pattern. Appropriate mesh size and shaped were obtained. The simulation results were compared with the experimental results of ball drop tests. The simulation results of the laminated glass model with two layers, lmm-triangle mesh shows good agreement with the experimental results. This laminated glass model was then implemented to the windshield of the car. Simulation of headform impact tests according to the EEVC protocol on pedestrian protection were performed. The results in terms of head deceleration, crack pattern and windshield energy absorption were compared with the test results. Good agreement can be seen.

This article deals with the design of CFRP composite monocoque chassis for Formula Student race car. The design objective is to maximize a specific torsional stiffness of the monocoque and also satisfy the safety requirement assigned by Formula SAE. The sandwich structure has been used regarding to its high flexural rigidity per weight. The thickness and stacking sequences of composite plies have been optimized for each particular zone of the monocoque chassis using the FEM simulation.

The purpose of this research is to develop the prototypes of advanced motorcycle seat and protective equipment of compulsory helmet wearing through experimental evaluation. In this prototype, suitable sensors for detecting pillion, strapping chin and wearing helmet of motorcycle users are integrated with the existing motorcycle and helmet. These sensors were developed and investigated through the experimental testing procedures. For the evaluation of pillion seat sensor, the hip of dummy hybrid III 50^th percentile male was used with the discrete values of mass on the sliding machine at each position of pillion seat. To conduct the experimental evaluation of strapping chin and wearing helmet conditions, the EN960 european standard headform were used at each position. Consequently, the functional detective range of the developed prototypes are identified and specified at pillion seat, chin strap and helmet wearing conditions. Additionally, these results are planned to develop an advanced system for supporting motorcycle users and increasing awareness of injury reduction.

According to increasingly stringent regulations on particulate emission from automotive vehicles, diesel engine must be equipped with Diesel Particulate Filter (DPF) to trap the Particulate Matter (PM) which are very harmful to human health. Diesel particulate matters are composed primarily of unburned hydrocarbon (soot) and metal oxide ashes as solid fraction. DPF can trap PM with higher filtration efficiency and the process which can burn the soot into carbon dioxide is called regeneration process. Although regeneration process can burn the soot effectively, incombustible ashes will be remained inside the DPF channel causing engine back pressure. These metal oxide ashes are mainly derived from lubricant additives, engine wear and trace metals from diesel fuel. In this article, different nanostructures of diesel soot and metal oxide ash derived by diesel blending lube oil condition were briefly compared using Transmission Electron Microscopy (TEM) image analysis. Electron Dispersive X-ray Spectroscopy (EDS) analysis was introduced to investigate the chemical composition of particulate matters. Thermogravimetric Analysis (TGA) was also conducted to compare the oxidation kinetics of pure diesel soot and the influence of metal oxide ash on soot oxidation kinetics. Contamination of metal oxide ashes promoted soot oxidation rate due to the presence of metallic additives from lube oil acting as a catalyst on soot oxidation kinetics.

Underride truck crashes occur when a passenger car rides under the rear of a large truck. These kinds of accidents are especially dangerous because of the size difference between trucks and passenger cars. Therefore, it is necessary to install the Rear Underrun Protection Device (RUPD) at the rear of trucks for safety enhancement. The aim of this research is to design an effective RUPD which is strong enough to prevent a passenger car falling under the rear of the truck and able to absorb large amount of crash energy to minimize accident severity. The novel RUPD design, equipped with energy absorption guard and proper support structure is proposed in this paper. The study on the angle and separation distance of support structures is performed to find the proper design for the support structure of RUPD. The internal energy and displacement of various design of support structures are investigated by performing Finite element crash simulation in LS-Dyna. The FMVSS 223 standard is utilized as reference for the standard design of RUPD. The result shows that the support structure angle of 20 degree yields optimal displacement and energy absorption. Moreover, the new proposed RUPD is able to avoid the A-pillar deformation and eliminates underride altogether.

Thailand is second in the road fatality rankings published by World Health Organization in 2015. Almost 80% of traffic deaths involves motorcycles and many of the passengers are children. However, there are still no appropriate head protection equipment for small child pillions. The child helmet should also be lightweight and have high energy absorption. This paper aims to develop a child helmet by using metal foam. The impact tests of the smallest size commercial motorcycle helmet were performed in TIS 369-2557 standard. The finite element model of an existing child helmet was developed and employed to simulate the helmet impact tests using both rigid dummy head and deformable child head. The helmet model was validated with experimental tests to obtain the baseline model. Good agreements can be observed. In addition, the deformable child head can give detail information of brain injury experience by the child during impact. The existing helmet model was redesigned with aluminium foam and was compared with the baseline model after impact tests. Improvement in terms of helmet weight and head injury mitigation can be seen.

Based on United Nation Economic Commission for Europe (UNECE) regulations, there are no existing standard procedures to identify the force performance of used tire which can be physically degraded by time. In vehicle safety, these tire forces in lateral and longitudinal directions are the key factors to response the driver decision during the brake application and maneuver conditions. Therefore, the objective of this research is to develop the used tire performances based on three vehicle testing standards such as brake test, steady-state circular test and severe lane-change test respectively. To assess the tire force performances, two tire categories which are used in those tests with the driving and pedal robot for the sedan vehicle are classified as new tires from 2018 and used tires from 2015, 2014, 2013. To identify tire force performances, various indicators for each test are determined. For example, the standard brake test from UNECE R13H is used to investigate tire friction force in the longitudinal direction. The severe lane-change manoeuvre and steady state circular tests are used to identify the lateral tire force from ISO 3888-2 and ISO 4138 respectively. As a result, it can be concluded that the tire force performances from new and used tires are different based on various indicators.

Parallel manipulators are robots with the capability to perform motion up to six degrees of freedom. This work presents a surrogate-based optimisation process for designing a 6-RSS parallel manipulator that is driven by six rotary actuators; the kinematic performance of the manipulator is defined by the volume of the total orientation workspace and the global conditioning index. The surrogate modelling technique was demonstrated by simulation to be highly beneficial in exploring the design landscape thoroughly even for a high-dimensional case with six design variables. Computational expense in the optimisation process was reduced by sequentially searching the surrogate models instead of the original performance indices. One platform geometry with the best compromise between the two contradicting indices was obtained in accordance with the weighted-sum function. Despite the fact that this work considers a small-scale 6-RSS parallel manipulator, the presented surrogate-based optimal design framework is generic and can be applied to different types of manipulators.

Shear failure yield line in Drucker-Prager yield surface for conventional atomized iron powder has been estimated with critical stress state and uniaxial failure stress state by single shear test and uniaxial failure test for green compact. Lateral force measurement test was also conducted using newly devised instrumented die compaction system to identify compaction yield characteristics as Cap yield surface. By those estimations, materials input parameters for Drucker-Prager Cap model have been determined successfully. Finite element analysis of simple closed-die compaction has been conducted and good correspondence in variation of compaction pressure with densification has been recognized.

This paper reports the results of failure analysis of an idle gear shaft of a gearbox in a hot re-rolling steel mill in Thailand. The shaft failed prematurely after only about 6,000 hours of service which was very much lower than the expected working life of 40,000-50,000 hours. The results showed that the shaft failed by fatigue fracture. Beach marks on the fracture surface were clearly visible. Fatigue cracks were initiated at two corners of the keyway of the shaft. Relatively large final fracture area of the fracture surface indicated that the shaft was under a very high stress at the time of failure. The root cause of the fracture is poor design and poor machining of the keyway. Too small fillet radii at the bottom of the keyway gave rise to stress concentration resulting in excessive stresses at the keyway corners. These high stresses led to fatigue crack initiation at the keyway corners followed by crack growth, and final fracture.

Currently, composites play an important role in the automotive industry where the weight reduction is a key of success due to its high strength to weight ratio. However, the replacement of metals with composites cannot be entirely archived, the joining between composite-metal is required. Bonding with adhesive is one of the most important methods in composite-metal joining. However, the accurate failure prediction of adhesive layers is still lacking due to the complicated state of stress at free-edges of specimens. The aim of this work is to investigate the failure behavior and analysis of acrylic adhesive which is particularly designed to provide superior bonding between composites and metals. Since an adhesive is generally a polymer, its failure depends on the hydro-static pressure. The chosen criterion needs to take into account this dependency. In this study, the Drucker-Prager failure criterion has been used. The parameters were characterized by tensile, compression and double lap shear tests. Then the FEM simulation was performed to predict a failure of single lap shear tests as a validation of model.

In the automotive field, most of the manufacturers are looking to replace the material steel, aluminium with lightweight material like carbon fiber or glass fiber composite. The purpose are due to their relatively high strength, higher chemical resistance, flexible usage temperature and higher stiffness than steel. In this study, mechanical properties of carbon fiber and glass fiber reinforced polymer were investigate. It was find that the tensile strength of carbon fiber composite is approximately 11% higher than that of glass fiber, almost twice in Young's modulus than that of glass fiber. Carbon fiber is two times higher than glass fiber in both flexural stress and young modulus of flexural three points bending test. Image analysis of fracture and damage were detect by field emission scanning electron microscopy (FESEM) in microstructure scale to observe the fracture mechanism. Observed different failure mode in fiber and resin. Chemical composition of composite and fibers were investigated by using electron dispersive x-ray (EDX) spectroscopy that gave out in 88 w.t % of carbon and 12 w.t % in carbon fiber twill (CFT) composite. On the other hand, glass fiber woven (GFW) composite contained 72.7 w.t % of C, 20.7 w.t % of O2, and the rest contained Si, Ca, Al, Mg and Cl.

Laminated composite beams are widely used as structural components in aerospace and wind energy industries. For airplane wings and wind turbine blades, the beams, commonly called spars, provide principal stiffness against bending deformation of the structures. The present work is focused on composite cantilever beams with a constant I-cross section. A unidirectional (UD) Glass/Epoxy lamina was chosen for composite material. The overall dimension of the beam is 50 × 55.2 × 2,500 mm. Various stacking sequences were assigned to the flanges and the web of the beam. A uniform distributed load was applied to the upper flange. The deflection results from First-Order Shear Deformation Theory (FSDT) and Finite Element Analysis (FEA) are in good agreement. The effective longitudinal modulus (E_x) of the flanges has strong influence on the bending stiffness and the beam deflection. Understanding important roles of materials and beam construction can help improving the design of I-beams. The validated FEA procedure can be extended to the analysis of realistic spars, which is based on an I-cross section plus curve, taper, and twist along the length.

The paper studied the strength and deformation characteristics of a composite wing of a two-seater seaplane to get the certificate of airworthiness which static testing is indispensable. The primary wing structure component includes upper and lower skins, leading edge, trailing edge, a root rib and main spar. The main purpose of static testing is to examine the bending strength of the wing. The testing results show good agreement with the FE analysis results, and the bending strength of wing is strong enough to support the limit loads (the maximum loads to the expected in service) without detrimental and permanent deformation, and without failure for at least 3s under the ultimate loads (limit loads multiplied by prescribed factors of safety), which meets the requirement of ASTM F2245-16c (Standard Specification for Design and Performance of a Light Sport Airplane).

The resistance spot welding method is commonly used in the cylindrical battery packing because of production costs. However, its quality is lower than other welding methods. To improve the quality, three parameters which are slot geometries of nickel conductor strip, welding position and welding position sequence are studied in this paper using both simulations and experimental methods. According to different slot geometries, if the slot length is longer than the positive battery terminal diameter, the high welding current flows through the welding point. To weld different positions, it results in structural deformation of the positive battery terminal which directly affects the contact pressure. As different welding position sequences for three welding spots on the positive battery terminal, it is found that the sequence starting at the middle is better than which from the sides. In conclusion, these parameters can be used to improve the welding quality; nevertheless, there are still other parameters which will be studied in the future.

Fuse Deposition Modelling (FDM) 3D printing is nowadays becoming more standard equipment in various fields of study as it can offer both low operating expenses and small investment cost; however, it has been accepted that the printed parts form this kind of printers is not too strong compare with the other Manufacturing technique. This study aims to analyze the effects of both Printing patterns and Infiltration percent on the tensile properties of the specimens obtained by an FDM printer. The specimens have been fabricated with three difference directions that are Horizontal (H), Crosswise (C), and Vertical (V) and within these groups, they are also vary the Infiltration percent at 20% 60% and 100%. After that they had been tested under a Universal tensile testing machine and then these obtained data had been analysed by an Analysis of Variance with 23 level. The result shows that both of Printing Patterns and Infiltration percent can be effect on Tensile strength of the specimens with significant different at 95% confidence level. Beginning with an increase of infiltration percent, it can lead to very strong effect on increasing of the tensile strength. In the case of print patterns, it can be concluded that the maximum stress is C, H and V, respectively. Because of the C pattern printing, tensile testing is a direction that is aligned with the printing of the layer. (For example, like pulling several ropes together)

Mat-surface is a surface with microscopic irregularities whose dimensions are close to the wavelengths of visible light (400-700 nanometers).

The new method that utilizes fixed-abrasive tool to fabricate mat-surface without pre-masking and large scale back up facility, is proposed in our last report. The report clarifies that, mat-surface must be produced with fixed-abrasive process, If the relative motion between tool and work in grinding process can be realized as that in blasting,

In the reports, however, materials of workpieces which are ductile, such as steel and aluminium alloy, were selected. These materials are relatively easy to be indented. Therefore, in order to develop a new application of the proposed method, the method is applied to brittle material such as glass, it is investigated whether mat-surface can be obtained.

Production of technical parts for Mechanical Engineering field is very important. There are many conditions which the produced parts have to satisfy. Very important for functional parts are accuracy of final parts. This accuracy could be evaluated in different ways. For example it can be evaluated shape accuracy or dimensional accuracy. This paper is focused to Fused Deposition Modelling (FDM) technology which is used for Additive Manufacturing process. The parts in additive manufacturing are produced directly from virtual model and digital file which could be obtained by direct modelling with CAD software of by 3D scanning. Published paper deals realized research where the full factor experiment was prepared and measured shape and dimensional accuracy of produced specimens. There are designed two types of specimens with different shapes and dimensions. Digital models are processed with different different 3D printer settings. Measured values are evaluated by statistical methods.

Recently, environmental consideration, energy-saving performance and low fuel consumption become important, therefore personal mobility is actively developed. When vehicle become small, it is expected that human body behavior has a big influence on running performance. The influence is related to stability of vehicle and safety of its driver. Simulation is used as a method to investigate the interaction between vehicle and its driver, and the body behavior can be reproduced in advance. However, since it is necessary to consider the validity for the use of simulation, experiments to capture body behavior are indispensable. This research is aimed to obtain knowledge about dynamics of driver riding inside the vehicle. Therefore, subjects are placed on a simple truck simulating a vehicle. The truck is applied lateral acceleration and acceleration in the direction of travel, and the motion of subjects was recorded with the motion capture camera. From the measured data, human characteristics are examined by comparing the body behavior of subjects for each condition.

As the epidermis adapts to different environments, desquamation of keratinocytes is affected by the water content in the epidermis. The thickness of the outermost layer of skin is determined by the interaction between exfoliation and moisture evaporation. The balance between these processes is the key to healthy skin, but has not been studied. The present study constructs a qualitative numerical model of stratum corneum thickness based on the interaction between exfoliation and evaporation processes.

Knee's severe patellofemoral joint degeneration gives a lot of people difficulty to endure daily life because walking or any leg movement can cause serious pain. At present, physical examination, x-ray and MRI are often used to diagnose the condition; however, each of the methods has its own disadvantages. For instance, physical examination is highly dependent on the skill of the doctor who practiced the examination, which cannot avoid misdiagnosing the condition. X-ray can detect wounds and tears, but the accuracy is also not top-notch since the result of an x-ray is a 2-dimension picture. MRI is the most reliable method for diagnosing the condition; however, the cost is very high. We propose that other than x-ray and MRI, patellofemoral joint degeneration can be identified by analyzing vibrational signals obtained from an accelerometer attached to the patella while sitting and moving the leg up and down. At the beginning of the study, swine's knees are used to imitate human's knee. Swine's knees with various surface degradation levels are put on a machine that mimics the mechanism of knee motion. An accelerometer is mounted on the patella of the swine's knee while the machine is running to measure the friction and roughness induced vibration of the patella. The vibration results suggest that more surface degradation the higher vibration signal amplitude. Nevertheless, the method still needs a lot more improvement on the database and testing procedures, in order to make it accurate, dependable and affordable. Hence, with further analysis on patient's knees it is highly possible to determine whether patient's knee is degraded or not and at what degradation level.

Aerosol medicine exhalation through the nose treatment (ETN) has conducted as an effective treatment for Eosinophilic Chronic Rhinosinusitis (ECRS). In ETN, the patient inhales aerosol of inhaled corticosteroid (ICS) medicine from mouth using portable inhaler. Then a part of the aerosol still floas and remains in upper airway. When the patient exhales inhaled air through the nose, the aerosol is effectively transported on the walls of middle meatus and olfactory fissure. The mechanism of how ETN improves ECRS with asthma is still controversial even though ETN gets a lot of attention as a treatment method for ECRS with asthma. In this study, computational fluid dynamics (CFD) analysis of aerosol transport phenomena were performed based on patient CT data in order to evaluate the therapeutic effect of ETN numerically. Three cases were selected in this study, one is a patient who had ECRS with asthma and a history of endoscopic sinus surgery and the others are healthy cases. 3D anatomically accurate patient-specific models were reconstructed from the data obtained using multidetector CT scanner with medical imaging software package. The entire series was loaded into the software, and then the nasal-pharynx airway was identified in each of the axial images based on predefined threshold of - 300 Housfield units relative to the surrounding tissue. The nasal-pharynx airway models were exported into a CFD meshing software package to generate discrete volume cells. This study used both a Euler-Lagrange particle transport model for aerosol transport and a model for complex intranasal turbulent flow. This study analyzed both inhaled state and exhaled state, and compared the aerosol deposition characteristics under conditions by changing the particle diameter and flow rate of aerosol. As a result of CFD analysis, amount of aerosol deposition depended on particle diameter and flow rate, and tendency of aerosol deposition was consistent in all cases analyzed in this study. Furthermore, in the inhaled state, aerosol mainly deposited in nasal meatus areas where not contribute to treatment of ECRS. Exhaled state was more effective treatment for ECRS compared to the inhaled state. The results show advantages of ETN as well as CFD analysis will contribute further development of ENT.

The knee is one of the important joint of human body to carry the body load. The deformities of knee joint affect the human activities. To treat the deformity knee, close-wedge High Tibial Osteotomy (HTO) was one of the popular techniques to adjust the strain distribution on the deformity knee close to the normal by shifting the mechanical axis toward the lateral side. This research aims to evaluate the strain distribution on the varus knee corrected by zero degree, three degrees valgus and three degreesvarus close-wedge HTO under walking load. The result was shown the lowest strain distribution occur on the three degreesvarus model following by zero degree and three degree valgus model respectively. The surgeon should be correct the varus knee by three degreesvarus close-wedge HTO to get the strain distribution on the bone closet to the normal knee.

Proximal femur is connected between pelvis and the lower extremity to carry the body weight that transfer from the upper body to the lower part. The patients, had the proximal femur bone tumor had a problem in daily activities. The most treatment for bone tumor has two methods as radiation and surgery method. The surgeon removed the bone tumor, replaced with the other proximal femur and fixed by dynamic hip screw and four screws fixation. This study aim to analyse the postoperative results after surgery with finite element analysis, were divided into six cases as the same size proximal femur, 15% and 30% small proximal femur, 15% and 30% large proximal femur and the same size proximal femur constructed by polymethyl methacrylate (PMMA). The result were shown the maximum strain on the small size higher than another cases under walking and stair-climbing load and the same size proximal femur constructed by PMMA had the lowest maximum equivalent of total strain. The surgeon should be replacing the proximal femur with the same or the larger size of femur or the same size constructed by PMMA for a good clinical result.

The child patients of hypoplastic left heart syndrome undergoes major operations such as the Norwood procedure, the Bidirectional Glenn procedure and the Fontan procedure. Patent Ductus Arteriosus (PDA) stenting, which is instead of these procedures, is recently performed to prevent closure of ductus arteriosus and to alleviate the burden for the patient. This study clarified that hemodynamics in aorta-pulmonary artery system and mechanism of thrombus formation using Computational Fluid Dynamics (CFD) analysis and Particle Imaging Velocimetry (PIV) measurement. As a result of CFD analysis, low wall shear stress was observed at neighborhood of PDA stent. From results of CFD analysis and PIV measurement, the main blood flow was formed toward from aorta to pulmonary artery and there is no blood stagnation region in PDA.

Cancer is one of the leading causes of morbidity and mortality worldwide. Microwave ablation is a minimally invasive treatment procedure that uses heat from microwave energy to destroy cancer cells. The effectiveness of this technique is associated to the microwave power input and heating time of treatment during the process, as well as the type of cancer tissue. The microwave power absorbed of each cancer tissue type is different and effect on the choice of treatment conditions. This research aims to investigate the effects of tissue type and microwave power input on the temperature profile and the efficiency of cancer treatment during microwave ablation. An experiment in ex vivo different tissues of porcine during microwave ablation via microwave antenna is studied. The types of tissue studied include skin tissue, liver tissue and lung tissue. The microwave power input of 60 W, 80 W and 100 W are investigated. The heating time of 360 s is selected for the study. An infrared thermometer camera is used to measure the temperature profile of tissues. The results reveal that the temperature profile and the ablation size in the case of skin tissue are higher than the liver tissue and lung tissue, respectively. In addition, the temperature profile of all tissues increases with greater microwave power. This research provides the essential aspects for a fundamental understanding of heat transfer within porcine tissues in microwave ablation process and can be used as a guideline to improve the efficiency of cancer treatment.

We have carried out the verifications of the solutions for the equations governing fluid flows. The equations solved are the similar equation of the boundary layer flow and the two-dimensional Navier-Stokes equations in the formulation of the stream function and the vorticity. The methods of the verification are the interval analysis and the Krawczyk operator based on the fixed point theorem. A modified Gaussian elimination method is introduced to solve the system of linear interval equations. The Krawczyk operator presents the results with a high accuracy. The modified elimination method gives the results with an accuracy of one or two order(s) of magnitude higher than those obtained by the original interval analysis.

Stability of rice paddy organic content is essential for the production of high quality rice. For this reason it is important to design a proper storage room with sufficient ventilation and moisture removal capability. Airflow dynamics in terms of velocity profile were modelled through computational fluid dynamic (CFD) simulations in Fluent 6.3 program across the three different geometrical design of paddy storage room. The selection of turbulence model used in CFD is an important process due to the uncertainty of turbulence model in different operating scale. This research used a turbulence model and RNG k-ε model to calculate along the simulation of Discrete Ordinances (DO) type radiation and the heat flux was set to 800 W/m². The results of this study have shown that Model C with pyramid-like roof demonstrated the optimum moisture removal through convection mechanism with the lowest average velocity of 0.175 m/s and the average temperature of 365.88 K. The CFD technique could be suitable for the simulation of airflow, permitting decrease in time and cost in the evaluation of airflow inside storage facility for paddy rice.

In order for wind technology to compete with conventional sources of energy in terms of energy production costs, researchers are working on different ways to increase the energy density in wind and therefore augment wind turbine power output. Concentrator augmented wind turbines (CAWTs) have been thought to be one of the ways to augment wind turbine power output and hence improve the cost effectiveness of wind energy. This concept involves enclosing the wind turbine rotor with a duct that reduces in cross-sectional area downstream of the blade-plane and hence increasing mass flow rate through the turbine. No efforts have been done to commercialize this concept because little is known about the wind flow behaviour in the CAWT, its influence on turbine power output and the optimum concentrator design parameters. The main objective of this research is to propose a new design for CAWT and optimize the concentrator design parameters. Furthermore, the effect of wind velocity and air pressure on the proposed design concepts are also investigated. Four different CAWT design concepts were designed and simulated using Solidworks and Computational Fluid Dynamics (CFD) tool Ansys Fluent, respectively. The wind velocity and air pressure vs. the position of convergent nozzle were plotted. Results showed an outstanding improvement in wind speed, which is 16.1 m/s (5.4 times increment), over the 3 m/s inlet wind velocity in the design concept 3 (CAWT 3.0) with the nozzle angle 20°.

This paper proposes an extension of a new concept for four-bar path generation and a new penalty constraint handling technique from our previous work to a motion generation problem. The proposed technique could neglect the timing constraint for problems without prescribed timing, which is found to be an efficient technique for a four-bar path generation problem. Later, the remaining constraints are solved with a new constraint handling technique that also gives high performance. The technique is one kind of penalty function techniques. The present work proposes to combine the previous two methods for solving the four-bar motion generation problems. The comparative study, optimisation of motion generation problems with a new and a traditional penalty techniqueare solved by using self-adaptive population size teaching-learning based optimization (SAP-TLBO), is presented. In this study, three new motion generation test problems are used to test the proposed technique. The results show that the new technique gives acceptable results and can be applied with the motion generation problems without prescribed timing.

In this paper the in-house technique mesh moving function based on AVL-FIRE has been developed as a simulation tool to investigate the in-chamber flow phenomena of the Wankel rotary engine. The meshes from the starting rotor position at 165° BTDC until the ending rotor position at top dead center (TDC) have been created and connected together. The numerical simulations between an intake stroke and the end of a compression stroke have been successively performed. The results are validated with the selected publication on various engine speeds, at 675 rpm and 1170 rpm. In parallel three refinements of meshes have been carried out, in order to optimize the suitable meshes' elements for the calculation of this engine type. In addition, the turbulence models, which are standard k-ε and Large Eddy Simulations (LES), have been varied for detailed investigation of their predictive capabilities. The simulation results show that the flow phenomena are well corresponding to the experimental data in both engine speeds, especially with the LES. It could be also identified that the LES model performs better on predicting the flow field both in directions and characteristics. Moreover, there is no evidently difference on the results between the medium (c.a. 100,000 elements) and fine (c.a. 1,000,000 elements) meshes comparing to the experimental results.

This paper presents the finite-surface method for solving the Navier-Stokes equations (NSE). This method defines the velocities as a surface-averaged value on the surfaces of the pressure cells. Consequently, the mass conservation on the pressure cells becomes an exact equation. The only things left to approximate is the momentum equation and the pressure at the new time step. At certain conditions, the exact mass conservation enables the explicit n-th order accurate NSE solver to be used with the pressure treatment that is two or four order less accurate without losing the apparent convergence rate. This feature was not possible with finite volume of finite difference methods. The convergence rate for laminar flows are presented. In addition to these result which was already presented elsewhere, this work presents a resolution criteria needed to achieve a DNS-like solution. The turbulent channel flow with friction Reynolds number 590 is used in this study. Previously, it was found that a fourth-order scheme is effectively 10X faster than the second-order scheme, at the comparable accuracy. The newly developed sixth-order FSM is 4X faster than the fourth-order scheme and thus it is a very interesting numerical method for solving turbulent flow. This speedup is possible due to the reduction of the number of grid points.

Patient lifting equipment can help the lifting of patient movement completely. It can help reduce the risk of disease that can be caused by lifting the patient and reduce the impact on the patient caused by lifting the patient in the wrong way. In addition, it can help to reduce the working time and reduces the number of personnel in moving patients. Including it can be to prevent the occupational disease on the service providers. This study aims to analyze the stress distribution and displacement to design of patient lifting equipment. The three weight conditions of 60 kg, 80 kg, and 120 kg are considered for studying about stress distribution and displacement at various points. In this test, ASTM A36 steel is used as a strength material tester. The results found that the maximum stress distribution and displacement is in the sling bar of the equipment. The obtained values will provide a basis for the guideline to design of patient lifting equipment to lift patients to suit in each situation such case from a private car go to bed or and wheelchair and from bed or and wheelchair go to a private car.

Shortage of workers in manufacturing industry has become one of the critical issues in every industry nowadays. Valves manufacturing process is involved forging and trimming process of brass workpieces which are hazardous and able to harm the workers. The aim of this project is to develop an automatic handling of valves in trimming system for replacing human workers. A 6-DOF articulated robotic arm is integrated with vision system for effectively picking the workpieces from the feeder and placing them to the rotating die for being trimmed. One of the challenging problems is the uncertainties of the shape of the forged workpieces related to flash. The specially designed impactive gripper and machine vision are developed to resolve those uncertainties. The gripper is a parallel jaws gripper designed to grip and hold an object with irregular geometries. For the selected model of valve, the system is able to work at 1,033 pieces hour at 96.67% success rate which is comparable to the capacity of the current human workers.

We have proposed a surrounding environmental recognition method using conical scanning distance measurement for mobile robots. The conical scanning method has a high robustness against ambient light noise and its calculation cost is low. This report describes the principle of this method and the two implementations. The first application is the quadrupedal wheeled robot. The robot can recognize a stair in sight, approach to it and climb. A second application is the indoor-outdoor wheeled mobile robot. The robot can recognize its position and obstacles on floor from information of a laser range finder and a 3D ToF camera. The validity of this method was confirmed by these robotic applications.

Soft gripper can grasp various types of objects even deformable objects or complex shapes. In this work, the design of a soft gripper is inspired by a tube foot of a starfish. Tube foot can deform in multiple directions. The proposed gripper has three soft silicone fingers which are driven by pneumatic actuation. Each finger can be curved in 6 directions using a three sided air chamber. This gripper can be controlled by a binary command into four states: home, open, close and twist. The tube feet inspired soft gripper was developed, modelled and tested.

Thailand has been used the R-32 refrigerant in air conditioner since 2016, while it has high global warming potentials (GWP = 675). A propane refrigerant (R-290) is introduced as a newly alternative refrigerant, due to the global issue on refrigerant substitution for friendly environment. It has GWP of 4, which is 169 times lower than R-32. In this study, the theoretical energy efficiency was analysed under the Thailand's conditions at the saturated evaporation temperature of 10°C and the saturated condensation temperature of 47°C. However, the propane is highly flammable; therefore, the safety must be considered. The results showed that the coefficient of performance of propane was 5.54, which was 7% higher than R-32. The wall type air conditioner with propane refrigerant would be safe from fire if it was installed at a height higher than 1.8 m above the floor level and the floor area was larger than 17 and 23 m² for air conditioner cooling capacity of 3375 W and 5000 W, respectively.

This work studies the novel solar water heater using natural black rocks as the absorption material. The objective of this study is to compare the thermal performance of solar water heater between using black rocks and black copper pipes. Both options were tested at the same parameters such as 0.8 m² collector area, angle tilted 19° and 30 litters of water tank volume. The experimental results showed that the maximum mean temperatures of solar water heater of absorption type using natural black rock system and black copper pipes system were 54.3 °C and 50.7 °C, respectively. In addition, the efficiencies of the water heater of absorption type using natural black rock system and black copper pipes system were 44.6% and 33.5%, respectively. Therefore, the water heater of absorption type using natural black rock system is another option used in the household sector to reduce the energy consumption of the country.

This paper examines the effects of structure and wettability on water transport behaviour in PEM fuel cell gas diffusion layers (GDLs). Different GDL materials, including carbon cloth and carbon paper with and without PTFE and MPL coatings, were used in this study. The breakthrough pressure of liquid water, water flow rate and water retention in the GDL were measured. For the GDL with and without MPL, the results indicate that the paper GDLs require higher breakthrough pressure than the cloth ones. Compared to the untreated GDL, applying PTFE on the GDL increases breakthrough pressure up to 1.5 times while it decreases water flow rate and water retention up to about 3.8 and 0.5 times respectively, over the tested conditions. The results also show that applying MPL on the GDL surface has greater impact on breakthrough pressure than applying PTFE. Liquid water requires up to about 4 times greater pressure to break through the other side of the GDL with the MPL. By applying MPL, the amount of water retention and flow through the GDL also reduced greatly, to almost zero. In addition, the results suggest that the GDLs are degraded after being exposed to water, which causes a significant decrease in breakthrough pressure and an increase in water retention.

Oversizing has been seldom concerning in Thailand. However, oversizing causes short-term operations of an air-conditioning (AC) unit and excessive power consumptions. In addition, multiple operations of oversized AC units can be faulty operations when they are used to serve in an open space area because interaction among AC units are not considered before installations. This paper collects data operations of the multiple supply duct split-type air-conditioning (SAC) units used in an open space from additional sensors installed in zone and return temperature. Significant wireless sensors are added for measuring temperature effect among a interaction area between two SAC units. To measure the system variation caused by system interaction, runtime fraction (RTF) is used to quantify the compressor runtime ratio which equals to a stage-on time operation over the cycle time at an AC design condition. The results show that one of the four SAC units performs under-sizing instead of oversizing performance because it runs continuously without off cycling. To diagnose this issue, interactions between zone and return temperature are quantified in terms of correlation coefficient, which demonstrates that this SAC results in higher oversizing of the rest SAC units. This interaction analysis can be further used to design a soft-repair algorithm to reduce oversizing effect of the multiple SAC operations.

Influences of diamond-shaped baffle (DSB) insertion in a heat exchanger tube on its thermal performance are experimentally presented. The DSB elements were repeatedly mounted into the tube using two straight small rods to connect the DSBs together to produce the longitudinal vortex flows inside. The experiments were carried out in a constant surface heat-fluxed tube equiped with DSBs. The DSBs were placed periodically with an attack angle of 45° and a pitch spacing of three times of tube diameter (PR=P/D=3) while four different DSB heights called blockage ratios (BR=b/D=0.1, 0.2, 0.3 and 0.4) were offered. Air was used as the test fluid flowed into the tube to yield the Reynolds number (Re) in a range of 4190-26,000. The heat transfer rate and the pressure drop of the current work were presented in terms of Nusselt number (Nu) and friction factor (f), respectively. The experimental results showed that the DSB provides the increase in the heat transfer around 3.53-4.16 times higher than the smooth tube while friction factor increases around 16.68-29.52 times. To evaluate the gain of using the DSB, the thermal performance factor (TEF) is determined in a range of 1.25-1.55 whereas the highest TEF is found at BR=0.1.

This aim of this study was to experimentally characterize the performance of Savonius wind turbine. The turbine rotors were modified by varying the distances, measured from blade tip to the most concave point of rotor. To achieve this objective, the investigated parameters were shape factor, including 0.5, 0.4, 0.3, and 0.2 while the Reynolds numbers were set as 136,640 and 156,160. The results showed that the Savonius rotor performed better performance at the higher Reynold number. Also, the tip speed ratio and shape factor were found to have a strong influence on the characteristic of power coefficient. The maximum power coefficient was obtained during the tip speed ratio of 0.4-0.6 while the shape factor of 0.4 provided a better performance than other rotors. This corresponds with the modified rotor 1, having the higher power coefficient compared to conventional rotor by 6.67% and 18.75% for a Reynolds number of 136,640 and 156,160, respectively.

The experiments on contact thermal sensations felt by subjects were performed under two conditions, namely, when seated outside and in an artificial climate chamber. There was a high correlation between the contact thermal sensation and the seat surface heat flux for thermal stimulus in a hot environment. It could be quantified that the effect of the thermophysical properties of a seating surface material on the contact thermal sensation. For cold stimulation in a cold environment, the trends that were seen for hot stimulus in the hot environment could not be observed. It was concluded that this was due to the large contact thermal resistance arising from the differences in insulation performance of clothes. In an outdoor environment dominated by solar radiation, the effect of contact thermal sensation on the whole-body thermal sensation could not be comfirmed.

Energy management has become one of the main issues in world energy scenario, every energy consumed system should be investigated and developed to increase its performance; especially air-conditioning systems which consumes more than half of the total power required by one air-conditioned building. In agreement with "Montreal Protocol on Substances that Deplete the Ozone layer", HCFC-22 was stopped its production and its refrigerating system must take another refrigerant; HFC-32 as the working fluid. This work presented information about two 12,000 Btu/h HFC-32 split-type air-conditioning systems with the hermetically sealed swing compressor (so called Inverter compressor) and the hermetically sealed rotary compressor. Both systems were placed in two identical rooms where 3,500 Watt heaters were also set in the middle of the rooms and operated under the constant heat flux condition in two different indoor temperatures; 20 and 22 Celsius. From experiment results in both indoor temperatures, the system with the hermetically sealed swing compressor escorted better energy consumptions, Coefficient of Performances (COPs) and Energy efficiency ratios (EERs) than those of another system with the hermetically sealed rotary compressor by 29.70% and 31.86% at 20-and 22-Celsius room temperature, respectively. The performances of both HFC-32 systems in different indoor temperatures were variant. The double pipe heat exchangers (DPHXs) were also investigated in this work, the COPs of the system with the swing compressor and DPHX were higher than those of another system with the rotary compressor and DPHX by 65.17% and 75.88% at 20-and 22-Celsius room temperature, respectively. The information in this work was used in making decision on the A/C system selection, as well as, the A/C energy management to reduce total A/C power consumption in macro views.

The internal resistance is one of the most important parameters which directly relate to battery performance in terms of output power and heat generation. This research presents the internal resistance of the battery that is studied with using battery voltage behaviour. Lithium Cobalt Oxide (LiCoO2, LCO) battery is applied for the experiment. The voltage drop during the current discharge is calculated to obtain internal resistance by the current pulse technique (CPT). Three different terms of internal resistance are compared by the voltage drop characteristic. As the result, comparison of temperature profile between experiment and simulation was obtained by current pulse technique with discharge rate variations.

The flow around a rotating disk in a cylindrical casing is investigated by the direct numerical simulation. The sizes of the disk and the casing are finite and the flow field has a radial clearance and an axial clearance. The interaction of the flows in these clearances make complex three-dimensional flow structures. In the present study, the patterns and the bifurcation processes of the fully developed flows are classified and the developing process of the flow is identified. The torques acting on the disk surface and the rim of the disk are evaluated and the power laws governing the relations among the torque, the Reynolds number and the thickness ratio of the disk are determined.

Biogas produces from the degradation of organic compounds of garbage and water wastes from various sources such as ranch and agricultural industries, usually by the fermentation process with anaerobic microorganisms. Layers of sediment are often occurred that can block the flow and longer mixing time is required for a more homogenous mixing. The objective of this study is to solve the non-uniform and non-homogenous as well as to save the mixing time in the fermentation process of biogas production using a model-mixing reactor. Flow analysis using an image processing technique of the symmetric airfoil NACA0015 blade at different angles of attack and mixing velocities in a Continuous Stirred Tank Reactor (CSTR) was examined. The CSTR was equipped with two and three airfoil blades at the angles of attack 0, 10, 16(stall angle) and 20° operated at the mixing velocities at 80, 110, 140 and 190 rpm. The mixing efficiency was evaluated from the homogenous appearance of plastic particles (5 mm diameter) dispersed in water by an image processing technique. The results showed that the mixing efficiencies of CSTR with three blades were higher than that of the CSTR with two blades of about 1.3 folds. The mixing efficiency increased with increasing mixing velocities and angles of attack, and was almost constant when the blade angles of attack increased from 16° to 20° and the mixing velocity increased from 140 to 190 rpm. This may be due to the airfoil blade stall and the saturation of the mixing. A new blade design for the CSTR system from this study can give a more efficient stir and mixing flow which will not only be beneficial for biogas production in the laboratory scale, but also a model design for the industrial biogas production as well.

An experimental investigation on thermal characteristics in a heat exchanger equipped with 45° rectangular winglet pairs (RWP) is conducted using air flowing in a constant heat flux tube with Reynolds number (Re) in a range of 5,200 to 23,000. Parameters of RWP included three relative height or blockage ratios (BR = 0.06, 0.08 and 0.1) and two pitch-spacing ratios (PR = 1.0 and 2.0). The heat transfer and the pressure drop in the test tube are displayed in the form of Nusselt number (Nu) and friction factor (f), respectively. The investigation shows that Nu and f values of the tube with RWP insert are, respectively, in the range of about 1.55−3.2 and 3.76−6.44 times above the plain tube alone, depending on the operating condition. The maximum thermal performance for using the RWP is found to be 1.7 at the lowest Re.

Extrusion is one of the most widely used processes for polymer processing, e.g., producing film, pipe, sheet, cable and pellet. The shape of extrusion die has an important part for the manufacturing products. The purpose of this study has been to confirm the influence of nozzle shape on polymer flow. We calculated the die flow simulations in the various parameters. The calculation results are expected to improve the efficiency of pelletization. A commercial computer fluid dynamics program Ansys Fluent was used to calculate the die passage. The parameters for the calculations were taper angle, outlet diameter, properties of polymer and two models. The governing equations were the incompressible momentum equation and the continuity equation. As results, the increase in flow rate was confirmed by increasing taper angle and outlet diameter in the specific dimensional range. The average outlet velocity of single and multi-nozzle models almost corresponded in each same parameter.

The purpose of this study is to determine the optimal ratio of Y-shape pin fin height to plate fin height in order to maximize the cooling performance of the plate pin fin heat sinks. The three-dimensional model of plate pin fin heat sink is considered in this study. Computational fluid dynamic method is used as a tool for solving the model. In this study, four values of height ratio, 0.2, 0.4, 0.6 and 0.8, and five values of air velocity, 0.5, 1.0, 1.5, 2.0 and 2.5 m/s, are analysed. The results of the study showed that the optimal fin height ratio is 0.6 resulting in the lowest thermal resistance of the plate pin fin heat sink.

The unsteady supersonic jet formed by a shock tube with a small high-pressure chamber was used as a simple alternative model for pulsed laser ablation. Understanding the vortex ring formed by the shock wave is crucial in clarifying behavior of unsteady supersonic jet discharged from elliptical cell. The purpose of this study has been to reveal behavior of the supersonic jet and the vortex rings. The unsteady behavior of a flow is investigated numerically by solving the axisymmetric two-dimensional compressible Navier-Stokes equations. The system of the calculation is a model of laser ablation of a certain duration followed by discharge through the cell exit. The parameters for the calculations are the pressure ratio of the shock tube and the cell diameter. As a result, it was found that the diameter of the elliptical cell had the effect on the interaction between vortex rings and the jet.

Heat exchangers are the equipment used in variety of industries at all levels related to heat and thermal systems. Using heat exchangers at maximum efficiency are to reduce the amount of energy lost that impacts on environment and manufacturing cost in the industry. This research focused on comparing performances of two heat exchangers; two double-pipe heat exchangers were fabricated domestically with two different welding techniques (flare and Argon welding techniques). Both heat exchangers were tested on the same experimental setup and investigated for their thermal efficiency. Their working fluid was water, hot water and cold water flowed inside the heat exchangers were arranged as parallel (co-current) and counter flow configurations. Thermal efficiency when hot water and cold water flow rates varied in the range from 0.5 to 2 liters per minute, were also investigated. The results showed that the second heat exchanger fabricated with the Argon-welding technique showed the better thermal performance than that of the first heat exchanger fabricated with the flare technique. The thermal performances of the second heat exchanger were varied from 92% to 99% while the performances of another heat exchanger were varied from 32% to 38%. Therefore, the heat exchanger manufacturing played an important role to the heat exchanger performance. The same heat exchanger design but different fabricating technique caused lost in heat transfer process which affected the thermal performance and operating cost of the industry.

In order to study the horizontal particle separator, equipped in the External-Fired Gas Turbine system (EFGT), the model experimental investigation and numerical simulation have been set up. The particle separator is used for separate small particles from gas by passing the flow through a spiral, which creates a centrifugal force. The particles will be trapped to a collector before reaching the gas exist. This study aims to analyze the efficiency of separation based on various designs of screw and cone. The experimental results show that decreasing of the cone length, the system pressure loss could be significantly reduced and the capacity of particles capture could be increased. However, the deepest cone position provides the higher loss comparing to the others. Moreover, it is evidently that the reducing number of screw's turn and it s pitch, the better capture capacity of the separator could be obtained. In parallel, the numerical simulation has been setup to support the experimental studies. The conditional parameters, including number of mesh, air mass flow rate and outlet condition, have been varied. In addition, the validation of flow simulation has been accomplished. The results show that there is the compatibility between the numerical simulation and experimental investigation as well.

This research aims to develop a burning tank for making charcoal and experiment for the wood vinegar burning process using wood as raw material. To design, and operation of such a burning tank for making charcoal require a detailed understanding of parameters that affect the system performance. In the research, the device designed for testing and developing a burning system that can improve the distillation rate of wood vinegar. The developed system consists of two tanks, a burning tank for making charcoal, and a distrillation tank for collecting wood vinegar. The burning tank for making charcoal made of steel with 400mm diameter and 600mm long for containing 15-20 kg of wood provides tight airflow and has two exhaust ducts attached to top and bottom of the tank side. The distillation tank for collecting wood vinegar has 24 copper pipes with a diameter of 12mm, and 400mm long, resulting in a condensing surface area of 0.36 m² The condensing pipes installed in 65 litres tank contains cool water with a temperature of 30 °C to 40 °C, used as media for removing the heat from those pipes surface. In the experiment, four influent parameters are investigated; two kinds of woods, three fire conditions of airflow rate, three moisture contents in woods are varied and two positions of exhaust duct are observed. The developed system tested by using 15 kg of Eucalyptus and River tamarind wood within 8 hours, producing 6.39L of yield wood vinegar. The experiment results show that the interaction between the new model designed and parameters significantly effect on the yield percent of wood vinegar collected. That is the effect of the prototype and those parameters can increase the wood vinegar 16 times compared to the conventional system.