Table of contents

Preface

The Materials Research Society of Indonesia (MRS-Id) Meeting is a bi-annual society meeting of the MRS-Id or Himpunan Riset Material Indonesia (HRMI). The 2^nd MRS-Id Meeting was held in Bandung from 24^th to 26^th October 2016 while the first one was in Bali in 2014. It was co-organized by Physics of Electronic Materials Research Division, Faculty of Mathematics and Natural Sciences of Institut Teknologi Bandung (ITB).

The aim of this event was to deliver the focus of MRS Indonesia that is to promote materials related with science and technology in Indonesia, regional, and global. We were very pleased that this event could bring together scientists, researchers, and engineers in Indonesia, regional, and global to share their newest scientific works and discoveries in the field of materials science and engineering.

Approximately 160 participants have attended the meeting. Among the participants, there were 6 plenary speakers, 26 invited speakers, and 121 contributed speakers. Based on the country where the participants came from, they were from 10 (ten) countries namely France, Germany, Indonesia, Japan, Malaysia, Saudi Arabia, Singapore, Sweden, UK, and USA. This MRS-Id Meeting consisted of 10 (ten) symposia that cover the broad spectra of materials science and engineering.

The speakers of the meeting have submitted their full papers for possible publications in a proceeding of IOP Publishing (IOP Conference Series: Materials Science and Engineering) or a journal of IOP Publishing (Materials Research Express). After peer reviewed by experts in related fields, finally, this proceeding contains 36 accepted papers. In addition, there are 20 papers published in the journal after an additional peer-review process of the journal.

The Materials Research Society of Indonesia (MRS-Id) acknowledges the enthusiasm of the participants and numerous sponsors, all members of the committees, the international advisory board, Faculty of Mathematics and Natural Sciences of ITB, and all those who have contributed to the success of the 2^nd MRS-Id Meeting.

The next MRS-Id Meeting will be held in 2018. We are looking forward to welcoming you to the 3^rd MRS-Id Meeting!

Prof. Khairurrijal Khairurrijal

Chairman of MRS-Id Meeting 2016 / Current President of MRS-Id

Dr. Ferry Iskandar

Co-Chairman of MRS-Id Meeting 2016

Prof. Khairurrijal Khairurrijal (ITB, Indonesia), Prof. Kikuo Okuyama (Hiroshima University, Japan), Dr. Ferry Iskandar (ITB, Indonesia), and Dr. Satria Zulkarnaen Bisri (RIKEN, Japan)

Editorial Board

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.

Zinc oxide (ZnO) thin film as a transparent conductive oxide (TCO) for thin film solar cell application was successfully prepared through two step preparations which consisted of deposition by spin coating at 2000 rpm for 10 second and followed by annealing at 500 °C for 2 hours under O₂ and ambient atmosphere. Zinc acetate dehydrate was used as a precursor which dissolved in ethanol and acetone (1:1 mol) mixture in order to make a zinc complex compound. In this work, we reported the O₂ effect, reaction mechanism, structure, morphology, optical and electrical properties. ZnO thin film in this work shows a single phase of wurtzite, with n-type semiconductor and has band gap, carrier concentration, mobility, and resistivity as 3.18 eV, 1.21 × 10^-19cm³, 11 cm²/Vs, 2.35 × 10^-3 Ωcm respectively which is suitable for TCO at thin film solar cell.

The blends of synthetic rubber and natural rubber with nanosilica were prepared using a blending technique in presence of different filler volume fraction. The effect of filler on morphological and mechanical characteristics was studied. Utilization of human cadaver in means of medical study has been commonly used primarily as tools of medical teaching and training such as surgery. Nonetheless, human cadaver brought inevitable problems. So it is necessary to find a substitute material that can be used to replace cadavers. In orthopaedics, the materials that resemble in mechanical properties to biological tissues are elastomers such as natural rubber (latex) and synthetic rubber (polyurethanes, silicones). This substitution material needs to consider the potential of Indonesia to help the development of the nation. Indonesia is the second largest country producer of natural rubber in the world. This paper aims to contribute to adjusting the mechanical properties of tissue-mimicking materials (TMMs) to the recommended range of biological tissue value and thus allow the development of phantoms with greater stability and similarity to human tissues. Repeatability for the phantom fabrication process was also explored. Characteristics were then compared to the control and mechanical characteristics of different human body part tissue. Nanosilica is the best filler to produce the best nanocomposite similarities with human tissue. We produced composites that approaching the properties of human internal tissues.

Micro-air-bubble has a high potential contribution in waste water, farming, and fishery treatment. In this research, submicron scale of micro-air-bubble was observed to determine its stability in H₂O solvent. By increasing its stability, it can be used for several applications, such as bio-preservative for medical and food transport. The micro-air-bubble was assumed in spherical shape that in incompressible gas boundary condition. So, the random motion of particle (Brownian motion) can be solved by using Stokes-Einstein approximation. But, Hadamard and Rybczynski equation is promoted to solve for larger bubble (micro scale). While, the effect of physical properties (e.g. diffusion coefficient, density, and flow rate) have taken important role in its characteristics in water. According to the theoretical investigation that have been done, decreasing of bubble velocity indicates that the bubble dissolves away or shrinking to the surface. To obtain longevity bubble in pure water medium, it is recomended to apply some surfactant molecules (e.g. NaCl) in micro-air-bubble medium.

In order to find an alternative biosensor material which enables to detect the glucose level, therefore in this study, the interaction between Methacrylic Acid (MAA) based Molecularly Imprinted Polymer (MIP) with D-Glucose is investigated using the Density Functional Theory (DFT). The aim of this study is to determine whether a molecule of the MAA can be functioned as a bio-sensing of glucose. In this calculation, the Gaussian 09 with B3LYP and 631+G(d) basis sets is used to calculate all electronic properties. It is found that the interaction between a molecule of MAA and a molecule of D-Glucose was observed through the shortened distance between the two molecules. The binding energy of MAA/D-glucose and the Mulliken population analysis are investigated for checking possible interaction. From analysis, the MAA based MIP can be used as a bio-sensing material.

One of many applications of essential oils is as fragrance in perfumery. Menthol, benzyl acetate, and vanillin, each represents olfactive characteristic of peppermint leaves, jasmine flowers, and vanilla beans, are commonly used in perfumery. These components are highly volatile, hence the fragrance components will quickly evaporate resulting in short-lasting scent and low shelf life. In this research, said components have been successfully encapsulated simultaneously inside Polyvinyl Alcohol (PVA) using simple coacervation method to increase its shelf life. Optimization has been done using Central Composite Diagram with 4 independent variables, i.e. composition of menthol, benzyl acetate, vanillin, and tergitol 15-S-9 (as emulsifier). Encapsulation efficiency, loading capacity, and microcapsule size have been measured. In optimized composition of menthol (13.98 %w/w), benzyl acetate (14.75 %w/w), vanillin (17.84 %w/w), and tergitol 15-S-9 (13.4 %w/w) encapsulation efficiency of 97,34% and loading capacity of 46,46% have been achieved. Mean diameter of microcapsule is 20,24 μm and within range of 2,011-36,24 μm. Final product was achieved in the form of cross linked polyvinyl alcohol with hydrogel consistency and orange to yellow in color.

The conversion of the biomass into biodiesels via catalytic esterification and trans-esterification became an interesting topic due to the depletion of fossil-based energy. Homogenous catalysts such as HCl, H₂SO₄ and NaOH commonly used as catalyst, however, the use of this kind of catalyst causes more problems, such as the difficulties on the separation from the product and the pollution effect on the environment. Heterogeneous catalysts, such as Metal-Organic Frameworks (MOFs) give an alternative promising way to substitute these limitations due to their strong catalytic site, porosity, high specific surface area, and easy-separation and reusable properties. Herein, we reported the synthesis of MOFs based on zirconium(IV) and H₃BTC linker (H₃BTC = benzene-1,3,5-tricarboxylic acid) by solvothermal and reflux method. Solvothermal reaction at 120 °C was found to be the optimum method, that was indicated by most crystalline product compared to the simulated pattern in XRD analysis. The formation of the framework was characterized by FTIR analysis, which showed a significant shift from 1722 cm^-1 to 1620 cm^-1. The synthesized Zr(IV)-BTC was thermally stable up to 322°C as shown by TG/DTA analysis. This high thermal stability was related to the high oxidation state of Zr(IV), which give a significant covalent character to the Zr-O bond.

Dye-sensitized solar cell (DSSC), which has been firstly developed by Graetzel et al back in 1991, has attracted a considerable interest since its discovery. However, two of the main challenges that the DSSC technology will have to overcome towards commercialization involve device scale-up and long-term stability. In our group, the fabrication technology of DSSC has been developed from laboratory to module scale over the past few years, nevertheless, the long-term stability has still became a major concern. In this contribution, the long-term DSSC performance in relation to their scale-up from cell to module is investigated. The photoelectrode of the DSSCs were fabricated using nanocrystalline titanium dioxide materials that were subsequently sensitized using ruthenium-based dye. Additionally, TiCl₄ pre- and post-treatment were carried out to enhance the overall device efficiency. When fabricated as cells, the DSSC prototypes showed relatively stable performance during repeated tests over three months. In order to increase the output power of the solar cells, the DSSCs were then connected in a Z-type series connection to obtain sub-module panels. The DSSC sub-modules exhibit poor stability, particularly as indicated by the significant decrease in the short circuit current (I_SC). Herein, the effect of photoelectrode and sealant materials as well as module design are investigated, highlighting their profound influence upon the DSSC efficiency and long-term stability.

Nd₂Fe₁₄B magnet powder has been fabricated by mixing Fe, B, and Nd powder based on their stoichiometric proportion at 650°C for 2 hours. Heat treatment series were applied at 720°C for one hour and continued with annealing at 100°C for 4 hours on different Nd stoichiometric variations; 26.6 %wt, 32.6 %wt, and 40.6 %wt. The results obtained from the X-ray Diffraction (XRD) phase analysis of Nd-rich Nd-Fe-B alloy suggested that the alloy has monophasic composition with hard magnetic Nd₂Fe₁₄B phase as a composition. The mean of the crystal grain size was determined using XRD analysis, while the microstructure and composition of the alloys were analyzed using the Scanning Electron Microscope – Energy Dispersive X-ray (SEM-EDX). The magnetic properties characterization were determined using the Vibrating Sample Magnetometer (VSM), which indicates that the sample with 40.6 %wt Nd was able to achieve the highest remanence of 446.50 G and BHmax of 17.83 kGOe. Despite the high remanence result, the coercivity and BHmax value of the third sample was still lower than the commercial's but has adequate potential value.

Permanent magnet of Barium hexa Ferrite with formula BaFe₁₂O₁₉ has been made by metallurgy powder method from raw materials : Barium carbonate (BaCO₃ E-merck) and Iron Oxide (Fe₂O₃ from mill scale). Both of raw materials have been mixed with stoichiometry composition by using a ball mill for 24 hours. The fine powder obtained from milling process was formed by using a hydraulic press at pressure 50 MPa and continued with sintering process. The sintering temperature was varied : 1150°C, 1200°C, 1250°C and 1300°C with holding time for 1 hour. The sintered samples were characterized such as : physical properties (bulk density, porosity and shrinkage), magnetic properties (flux density, remanence, coercivity and magnetic saturation) by using VSM and crystal structure by using XRD. According characterization results show that the crystal structure of BaFe₁₂O₁₉ does not change after sintering process, but the grain size tends to increase. The optimum condition is achieved at temperature 1250°C, and at this condition, the sample has characterization such as : bulk density = 4.35 g/cm³, porosity = 1.03% and firing shrinkage = 11.63%, flux density = 681.1 Gauss, remanence (σr) = 20.78 emu/g, coercivity (Hc) = 2058 Oe and magnetic saturation (σs) 45.16 emu/g.

A new solar photocatalytic reactor (photoreactor) using TiO₂ nanoparticles coated onto plastic granules has been designed. Catalyst granules are placed into the cavity of a reactor panel made of glass. A pump is used to circulate wastewater in the photoreactor. Methylene blue (MB) dissolved in water was chosen as the wastewater model. The performance of the photoreactor was evaluated based on changes in MB concentration with respect to time. The photoreactor showed a good performance by degrading 10 L of MB solution up to 96.54% after 48 h of solar irradiation. The photoreactor was scaled up by enlarging the panel area to twice its original size. The increase in the surface area of the reactor panel and therefore of the mass of catalyst granules and reactor volume led to a three-fold increase of the photodegradation rate. In addition, the MB degradation kinetics were also studied. Data analysis confirmed the applicability of the pseudo-first-order Langmuir-Hinshelwood model. The proposed photoreactor has great potential for use in large-scale wastewater treatment.

Dye-sensitized Solar Cell (DSSC) is a third-generation solar cell that consists of a working electrode, electrolyte and counter electrode. One of the most important parts of DSSC is an electrolyte that roles as a medium and regenerates the electron transport of electrons in the dye. However, the liquid electrolyte has a lack of stability in long-term use and easily evaporate or leak in DSSC. Therefore, this study aims to investigate an effect of the addition of polymer material such as PEG 1000, 4000 and PVA 60000 for fabricating a gel electrolyte to solve the problems of liquid electrolyte. The synthesized TiO₂ nanoparticles used in this study was prepared using co-precipitation (CPT) method which produces TiO₂ anatase phase with a crystal size of 11.1 nm. DSSC has been successfully conducted and analyzed to evaluate its performance. The results showed that the efficiency of DSSC cells using gel electrolyte prepared with PVA 60000 was better than a liquid electrolyte, PEG 1000, 4000, with the efficiency could be obtained at 0.083, 0.018, 0.033, and 0.054%, respectively. The results demonstrated that the addition PEG and/or PVA could be enhanced the performance of DSSC due to gel electrolyte produced current and voltage more stable compared to the liquid electrolyte.

Esterification is a common route to produce carboxylic acid esters as important intermediates in chemical and pharmaceutical industries. However, the reaction is equilibrium limited and needs to be driven forward by selective removal one of the products. There have been some efforts to selectively remove water from reaction mixture via several separation processes (such as pervaporation and reactive distillation). Integrated pervaporation and esterification has gained increasing attention towards. Inorganic zeolite is the most popular material for pervaporation due to its high chemical resistant and separation performance towards water. Zeolite also has proven to be an effective material in removing water from organic compound. Zeolite can act not only as selective layer but also simultaneously act as a catalyst on promoting the reaction. Hence, there are many configurations in integrating zeolite membrane for esterification reaction. As a selective layer to remove water from reaction mixture, high Si/Al zeolite is preferred to enhance its hydrophilicity. However, low Si/Al zeolite is unstable in acid condition due to dealumination thus eliminate its advantages. As a catalyst, acid zeolites (e.g. H-ZSM-5) provide protons for autoprotolysis of the carboxylic acid similar to other catalyst for esterification (e.g. inorganic acid, and ion exchange resins). There are many studies related to zeolite membrane aided esterification. This paper will give brief information related to zeolite membrane role in esterification and also research trend towards it.

The search of alternative energy sources keeps growing from time to time. Various alternatives have been introduced to reduce the use of fossil fuel, including hydrogen. Many pathways can be used to produce hydrogen. Among all of those, the Water Gas Shift (WGS) reaction is the most common pathway to produce high purity hydrogen. The WGS technique faces a downstream processing challenge due to the removal hydrogen from the product stream itself since it contains a mixture of hydrogen, carbon dioxide and also the excess reactants. An integrated process using zeolite membrane reactor has been introduced to improve the performance of the process by selectively separate the hydrogen whilst boosting the conversion. Furthermore, the zeolite membrane reactor can be further improved via optimizing the process condition. This paper discusses the simulation of Zeolite Membrane Water Gas Shift Reactor (ZMWGSR) with variation of process condition to achieve an optimum performance. The simulation can be simulated into two consecutive mechanisms, the reaction prior to the permeation of gases through the zeolite membrane. This paper is focused on the optimization of the process parameters (e.g. temperature, initial concentration) and also membrane properties (e.g. pore size) to achieve an optimum product specification (concentration, purity).

Polypropylene (PP) is one of the most important polymers for microporous membrane due to its high void volume, well-controlled porosity, high thermal and chemical stability, and low cost. However, the hydrophobicity of PP becomes a limitation to broaden its applications. Furthermore, membrane fouling occurs more seriously on hydrophobic membranes than hydrophilic ones. To solve this problem, surface modifications have been developed to enhance PP membrane hydrophilicity without changing its bulk properties. Graft polymerization and plasma treatment are the most popular techniques for surface hydrophilization. Some studies showed that highly hydrophilic PP membranes with water contact angle less than 20° could be obtained by plasma treatment and graft polymerization. Furthermore, during plasma treatment, polar groups were formed on the PP membrane surface thus increased water uptake. To bring brief explanation on various research trends for PP modification, this paper provides a review of surface hydrophilization of microporous PP membrane, including plasma treatment and graft polymerization. The effects of surface modification on PP membrane performance such as porosity, water contact angle, and water flux are also discussed. In addition, the applications of modified PP membrane are presented as well.

The effects of molybdenum in stainless steel on the corrosion behaviour in nano fluids contain nano particle Al2O3 in the de mineralized water have been investigated. Open circuit potential (OCP), Tafel polarization and electrochemical impedance spectroscopy (EIS) testing was performed in the demineralized water contain nano particle 0, 01% Al2O3 as Nano fluid. Metallurgical techniques such as X-ray diffraction (XRD) and optical microscopy were used to characterize the alloys before and after corrosion testing. According to the open circuit potential measurement of the stainless steel in the de mineralized water and nano fluid media, it is showed that stainless steel with Mo showed more negative OCP compared without Mo stainless steel. The results of the Tafel polarization technique show that corrosion currents stainless steels in the nano fluid decrease with the increasing of Mo content in the stainless steel. Surface morphology of the specimens by optical microscope examination showed that microstructure of stainless steel SS 304 and SS 316 alloys relatively unchanged before and after corrosion testing nano fluids. X ray diffraction examination of stainless steel with and without Mo after corrosion testing depict that γFe is major phase without oxide phase on the surface of alloy

In the present work, we report the preparation of BCNO/SiO₂ phosphor synthesized using a microwave-assisted method. This method allows a lower temperature and a shorter reaction time than simple heating (furnace). The phosphors were prepared from precursors containing, boric acid, urea, citric acid and SiO₂ nanoparticles. To These precursors, silica nanoparticles were added at various concentrations from 0 to 5 %wt. The emission wavelength produced by the phosphor was varied by varying the fraction mass of the silica that were added to the precursors. The results showed that higher photoluminescence (PL) intensity was produced by the BCNO/SiO₂ with 3 %wt silica addition. The novelty of this research is using microwave heating for BCNO/SiO₂ synthesis, which is usually conducted using a simple heating method.

Understanding the transport and retention of iron oxide nanoparticles is critical in optimizing electromagnetic heating well stimulation. If the injected concentration or injection rate is too big, nanoparticles can build-up inside the pore throat, which can reduce the permeability of the reservoir. A numerical model has been created to describe the behavior of iron oxide nanoparticles in porous media. The model is coupling material balance equation and fluid flow in porous media equations. There are six parameters to be estimated through matching with experimental data: irreversible attachment rate, reversible attachment rate, irreversible attachment capacity, reversible attachment capacity, reversible detachment rate and permeability. All parameters were obtained directly through coreflooding result in previous study. We add Langmuir static isotherm test to limit the maximum adsorption capacity to provide a better estimation of concentration distribution. We use 1% NaCl solution as the base fluid and 45-50 mesh sand as the porous media. From the Langmuir static isotherm test, the maximum adsorption concentration is determined. Then, coreflooding is conducted using 10 ppm nanofluid and 12 cc/min injection rate. The proposed model is matched with the experimental data and its parameters are consistent with the maximum adsorption capacity provided from the test.

Li_1.33Mn_1.67O₄ (LMO) was successfully synthesized by solid state reaction method at temperature variation of 500, 600, and 700 °C. As-prepared samples are immersed in 1 lt 0.5M HCL for 24 hours to create vacant site for lithium ion. Lithium extraction process is employed by soaking the adsorbent LMO in 1 lt of Lumpur Sidoarjo for 24 hrs. SEM images of adsorbent with variation of calcination temperature show irregular shape with particles size in the range of 15-52 μm. The calcination temperature effects on the size of the grain and crystallinity of adsorbent. LMO 700 sample has the highest capacity of lithium adsorption with capacity of 29.8 mg/g. It is attributed to the high crystalline of LMO 700 sample compared with other samples.

One of important aspects in bone healing process is physiological level of calcium (Ca), and phosphorus (P) that can be altered by implantation of biodegradable porous iron. Therefore, this study aims to investigate the concentration of Ca, P and Ca/P ratio in the peripheral blood during the implantation period up to 4 months. Forty adult male Sprague Dawley rats were used and divided into 3 groups receiving different pore size of iron implants (pore size 450, 580, 800μm) and one group of sham. The implants (5x2x0.5mm) were inserted into flat bone defects at latero-medial of femoral bone. Blood sample was taken from ventral tail artery before and after 4 month of implantation. Calcium and P concentrations in the blood were determined by BA-88A Semi-Auto Chemistry Analyzer. Results showed that concentration of Ca and P are slightly higher after implantation than before implantation, except for the 450μm group. The Ca/P ratio before and after implantation was increased in the sham group, and decreased in the 450 and 800μm groups. Concentration of Ca, P and Ca/P ratio insignificantly change between before and 4 months after surgery in some groups.

Andrographis paniculata is one of 13 leading commodities Indonesian medicinal plants through the Ditjen POM. Andrographolide as main active compound has been shown to have many pharmacological activities, one of which is as α-glucosidase enzyme inhibitors which has clinical potential as an antitumor, antiviral, antidiabetic, and immunoregulator agents. This study aims to do nanoencapsulation of Andrographis paniculatar leaf extract to increase its active compound bioavailability and get a release profile through synthetic fluids media simulation. Nanoencapsulation with ionic gelation method result the encapsulation efficiency and loading capacity values of 73.47% and 46.29% at 2%: 1% of chitosan: STPP ratio. The maximum α-glucosidase inhibition of 37.17% was obtained at 16% concentration. Burst release at gastric pH conditions indicate that most of the drug (in this study is an Andrographis paniculata leaf extract) adsorbed on the surface of the nanoparticles an indicates that the kind of nanoparticle formed is nanosphere.

Synthesis of glucose coated Fe₃O₄ magnetic nanoparticles have been successfully prepared with co-precipitation method. Raw material of natural iron-sand was obtained from Buaya River, Deliserdang, Indonesia. The milled iron-sand was dissolved in HCl (37 mole %), and stirred in 300 rpm at 70°C for 90 minutes. Glucose was added to the filtered powder with varied content of 0.01, 0.02, and 0.03 mole, and precipitated by NH₃ (25 mole%). After drying process, the final product subsequently was glucose coated magnetite (Fe₃O₄) nanoparticles. The characterizations performed were true density measurement, FTIR, VSM, XRD, BET, and adsorbent performance by AAS. The FTIR analysis showed that M-O (bending) with M=Fe (stretching vibration) with υ = 570.92 and 401.19 cm^-1. While glucose coated well on nanoparticle Fe₃O₄, proved by functional groups C=O (stretching), M-O (stretching) and C-H (bending) with υ = 1404.17, 570.92, and 2368.58 cm^-1, respectively. Single phase of magnetite (Fe₃O₄) structure was determined from XRD analysis with cubic spinel structure and lattice parameter of 8.396 Å. The optimum conditions, obtained on the Fe₃O₄ nanoparticles with 0.01 mole of glucose addition, which has true density value of 4.57 g/cm³, magnetic saturation, M_s = 35,41 emu/g, coercivity, H_cJ = 83.58 Oe, average particle size = 12.3 nm and surface area = 124.88 m²/g. This type magnetic nanoparticles of glucose-coated Fe₃O₄ was capable to adsorbed 93.78 % of ion Pb. Therefore, the glucose-coated Fe₃O₄ nanoparticle is a potential candidate to be used as heavy metal removal from wastewater.

Dye Sensitized Solar Cell (DSSC) using natural dyes (chlorophyll, curcumin from turmeric extract, and anthocyanin from mangosteen extract) have been successfully fabricated for determining the effect of variation natural dyes, mixing dyes and acetonitrile in electrolyte toward characterization of DSSC. DSSC consists of five parts namely ITO (Indium Tin Oxide) as a substrate; TiO₂ as semiconductor materials; natural dyes as an electron donor; electrolyte as electron transfer; and carbon as a catalyst that can convert light energy into electric energy. Two types of gel electrolyte based on PEG that mixed with liquid electrolyte have utilized for analyzing the lifetime of DSSC. Type I used distilled water as a solvent whilst type II used acetonitrile as a solvent with addition of concentration of KI and iodine. The main purpose of study was to investigate influence of solvent in electrolyte, variation of natural dyes and mixing dyes toward an efficiency that resulted by DSSC. The result showed that electrolyte type II is generally better than type I with efficiency 0,0556 and 0,0456 %, respectively. An efficiency values which resulted from a variation of mixed three natural dyes showed the greatest efficiency compared to mixed two natural dyes and one dye, with an efficiency value can be achieved at 0,0194 % for chlorophyll; 0,111 % for turmeric; 0,0105 % for mangosteen; 0,0244% (mangosteen and chlorophyll); 0,0117 % (turmeric and mangosteen); 0,0158 % (turmeric and chlorophyll); and 0.0566 % (mixed three natural dyes).

Titanium silicon carbide (Ti₃SiC₂) is a kind of ceramic that has physical property value similar with metal. Ti₃SiC₂ has been synthesized through various methods based on solid state reaction. Although Ti₃SiC₂ has been synthesized through various methods by using various starting materials consisting titanium (Ti), silicon (Si), and carbon (C) the mechanism of Ti₃SiC₂ formation through sintering has not fully understood. The aim of this research is to reveal the mechanism happening during sintering. Two composition of starting material was used, 2Ti/2Si/3TiC and 5Ti/2Si/3C. The analysis through XRD and SEM-EDS shows that the formation of intermediate phases, TiC and Ti₅Si₃, takes place prior to the formation of Ti₃SiC₂. In other words, Ti₃SiC₂ can only be formed through solid state reaction between TiC and Ti₅Si₃. Since TiC has already available in the system 2Ti/2Si/3TiC, the phase purity of Ti₃SiC₂ in 2Ti/2Si/3TiC is always higher than that of 5Ti/2Si/3C.

Carbon electrodes for desalination system have successfully been synthesized with and/or without modified activated carbon by chemically activated using HNO₃. The freezing-thawing method was used to synthesize the carbon electrodes. In this study, 5 cycles of freezing-thawing were applied in the synthesized carbon electrodes (1 cycle is 12 hours for freezing and 6 hours for thawing). Electrochemical properties of the synthesized carbon electrodes with and/or without modified activated carbon were characterized and observed by cyclic voltammetry (CV) and Electrical impedance spectroscopy (EIS). The salt-removal percentage experiments were conducted to evaluate the performance of capacitive deionization (CDI) cell using the two pairs of carbon electrodes with each pair consisting of two parallel electrodes that separated by a spacer. The result showed that the salt removal percentage of the carbon electrodes with modified activated carbon has greater than the carbon electrodes without modified activated carbon, with reduction level at 55.7 and 24.8%, respectively.

Low carbon steel has a lot of applications in daily life because of its excellent properties. Among its excellent properties are good ductility, toughness, formability, and weldability. For the case of application that requires good wear resistant, carbon steel is not sufficient. For this case it is required to increase the hardness of carbon steel, such as by carburizing method. In this method one factor that affects the carburizing layer is metal substrate condition, i.e grain size. Another factor is temperature that could have significant role on the carburized layer characteristics. Therefore the present works focus in the correlation between degree of reduction of cold rolling and carburizing temperature on the carburized layer characteristic. Thermo-mechanical treatment was applied to the specimen with reduction of 0%, 30%, and 80% by mean of rolling before carburizing process. Carburizing processes were carried out at temperature of 850°C, 900°C, and 950°C. Examinations on carburized specimens were conducted by metallography and micro hardness test. The result showed that the specimen of 80% reduction giving the thickest layer and the hardest surface layer. In addition, at temperature of 900°C, the hardest layer was formed with the hardness at 1003 HV. However, the thickest layer was formed at the temperature of 950°C.

Andrographis paniculata (A.paniculata) contain the main active substances Andrographolide which helps lower glucose levels in diabetics by inhibiting the enzyme α-glucosidase. The ability of the extract A.paniculata in lowering glucose levels will increase with the technique encapsulation with a coating of composition Chitosan-STPP as a drug delivery to the target organ. This study aimed to get an overview of A.paniculata release profile of nanoparticles in a synthetic fluid media with various concentrations of coating and inhibition testing nasty shard extract in inhibiting the enzyme α-glucosidase. This research resulted in nanoparticles by coating efficiency and loading capacity of chitosan greatest variation of 2% and 1% STPP 60% and 46.29%. chitosan greatest variation of 2% and 1% STPP 60% and 46.29%. The ability of A.paniculata extracts as α-glucosidase enzyme inhibitors has been demonstrated in this study, the percent inhibition of 33.17%.

Bismuth ferrite powder (BiFeO₃/BFO) with high purity was synthesized by sol-gel process. It was used Bi₅O(OH)₉(NO₃)₄ and Fe(NO₃)₃.9H₂O as main compound sources. Citric acid (C₆H₈O₇) was used as fuell. As multiferroic material, BFO promises important technological applications in several devices like data strorage, spinotronics, sensor, actuator devices etc. This research would know the optimum process condition of sol-gel process to produce BFO powder by varying of sintering time. The novelty of this research is how to produce BFO in single phase by simple method. It was used calcination condition at 160°C for 4 hours and sintering condition at 600°C with varying of sintering time of 4, 6 and 8 hours. Thermogravimetric Analysis/Differential Thermal Analysis (TGA/DTA), X Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to characterize the powder. Loss of mass and heat flow were seen at TGA/DTA test at 160°C approximately (used as reference of calcination temperature). BFO powder sintered at for 8 hours has no secondary phase, meanwhile for another sintering time (4 and 6 hours) it has Bi₂O₃ as secondary phase. It is also show at SEM observation result that powder with sintering time of 8 hours has finer grain than of 4 and 6 hours sintering at the same temperature. The grains of BFO powder has heterogenous in size, shape and still agglomerated.

The aim of this research was to determine the effect of calcination temperatures on the ratio of atomic weight of Al/O that could affect the formation of γ-Al₂O₃ phase. The novelty of this research is how to produce γ-Al₂O₃ in single phase and nanosize by simple method (sol-gel method).The calcination process was performed at a temperature which varied of 190°C, 275°C and 320°C for 4 hours respectively and sinter process carried out at a temperature of 420°C for 6 hours. Calcination process at temperature of 320°C for 4 hours produces powder with the ratio of atomic weight of Al/O in accordance with the ratio of atomic weight of Al/O in Al₂O₃ compound, 0.6667 (2/3). This ratio is as expected for a compound according to formula of Al₂O₃. This condition also produces alumina powder with the smallest particle size on the nanometer scale of 84.5 nm. SEM test results show that the grain is still heterogenous in size and shape. The results also show that the grain is still agglomerated.

Research on the synthesis of Nickel–Yttria Stabilized Zirconia (Ni–YSZ) cermet for Solid Oxide Fuel Cell (SOFC) anode has been performed. The preparation was carried out through the reduction process of the Nickel Oxide–Yttria stabilized Zirconia (NiO–YSZ) ceramic. NiO and YSZ were prepared separately, the NiO powder was prepared by calcination of CH₄Ni₃O₇.xH₂O at 500°C for 3 hours, while YSZ powder was prepared by calcination of 7mol% Y₂O₃ and 93mol% ZrO₂ mixture at 1350°C for an hour. The NiO–YSZ ceramic preparation was carried outby mixing of YSZ and NiO powder with natural white starch by weight ratio NiO: YSZ: natural white starch = 4:6:1 followed by sintering at 1200°C for 4 hours. The completion of reduction process of NiO–YSZ ceramic was performed at 1000°C in flowing Argon (Ar) containing 10% Hydrogen (H₂) up to 4 hours. The characterisations include thermogravimetric analysis (TGA), XRD, SEM–EDX and Impedance Analyzer meter. The synthesised Ni–YSZ cermet at composition 33wt% Ni and 67wt% YSZ, shows relative density 70% and electrical conductivity 10^-2 S/cm at 700°C, it qualifies as anode for SOFC.

Silica mineral, which comes along with geothermal fluid in Dieng, is a product of erosion, decomposition and dissolution of silicon oxide based mineral, which is followed by precipitation to form silica mineral. This silica cell structure is non crystalline, and it contains 85,60 % silicon oxide, 6.49 volatile elements, and also other oxide elements. Among the direct potential application of this silica is as raw material in slow release fertilizer. Silica in compacted slow release fertilizer is able control the release rate of fertilizer elements. Two type of slow release fertilizer has been made by using silica as the matrix in these slow release fertilizer. The first type is the mixing of ordinary solid fertilizer with Dieng silica, whereas the second one is the mixing of disposal leach water with Dieng silica. The release test shows that both of these modified fertilizers have slow release fertilizer characteristic. The release rate of fertilizer elements (magnesium, potassium, ammonium, and phosphate) can be significantly reduced. The addition of kaolin in the first type of slow release fertilizer makes the release rate of fertilizer elements can be more slowed down. Meanwhile in the second type of slow release fertilizer, the release rate is determined by ratio of silica/hydrogel. The lowest release rate is achieved by sample that has highest ratio of silica/hydrogel.

The effects of irradiation by a corona glow discharge plasma on hidrophylicity properties of polyester and cotton fabrics were investigated. We used a corona glow discharge plasma reactor with multiple points to plane electrodes, which was generated by a high voltage DC. Factors that affect the hidrophylicity properties were identified and evaluated as functions of irradiation parameters, which include duration of treatment, distance between electrodes, and bias voltage. It was readily observed from SEM examinations that plasma changed the surface morphology of both polyester and cotton fibers, giving result to an increased roughness to both of them. Results also showed that the hidrophylicityof polyester and cotton fabrics improved by the treatment, which is proportional to the time of treatment and voltage, but inversely proportional to the distance between electrodes. Time of treatment that provided the optimum enhancement of hidrophylicity for cotton is 15 minutes which improved the wetting time from 8.16 seconds to 1.26 seconds. For polyester, it took 15 minutes of irradiation time to improve the wetting time from 7340 seconds to 2905 seconds. The optimum distance between electrodes for both fabrics in this study was found to be 2 cm. Further analysis showed that the improved hidrophylicity properties is due to the creation of surface radicals by free radicals in the plasma leading to the formation of new water-attracting functional groups on the fiber surface.

ZSM-5 is a synthetic zeolite which contains silica (Si) and alumina (Al) with the ratio of silica greater than the alumina. The catalyst is known as ZSM-5 because it has a pore diameter of 5 Å (angstroms) and it has more than five Si/Al ratios. The catalyst has a high production cost and a complex production process which is highly influenced by time and temperature. Based on that fact, the focus of this research is studying the production process of ZSM-5 and investigating the effect of time and temperature on the crystallinity and the morphology of ZSM-5. In this research, Latourette et al. method was used, followed by the calcination at different temperatures (500 °C, 600 °C, 700 °C, 800 °C) in 5 and 7 hours. Subsequently, ZSM-5 was characterized using XRD (X-ray Diffraction) and SEM (Scanning Electron Microscope). The XRD analysis shows that the peak of standard ZSM-5 synthesis is at 2 theta degree 23. Prior to the calcination, ZSM-5 has an average crystallinity of 37.7337%. However, after the calcination, the crystallinity of the catalyst increased as the temperature rises. At 500 °C, 600 °C, 700 °C, and 800 °C the crystallinity increases to 39.1959%, 44.0927%, 42.9425%, and 44.8806%, respectively. Meanwhile, calcination time affects the XRD peak intensities by increasing the ZSM-5 crystal cores. The longer the calcination time, the higher the peak intensity is.

Bilayer heterojunction of aluminium doped zinc oxide (AZO) and titanium dioxide (TiO₂) mesoporous has been successfully deposited on fluorine tin oxide (FTO) substrate as working electrode in dye sensitized solar cell. This layer was used as working electrode in quasi solid dye sensitized solar cell. The solar cell structure is FTO/ZnO/TiO₂/PGE/Pt/FTO using polymer gel electrolyte (PGE). In polymer gel electrolyte system, hybrid copolymer based on poly-TMSPMA (3-methoxysilyl propyl methacrylate) was used as a matrix to trap ionic liquid. An addition of aluminum as atom dopant also studied to observe the physical properties changes of photoanode related to solar cell performance. AlCl₃ was used as dopant material with the concentrations at 0.5 weight % and 1.0 weight% of zinc acetate dehydrate as raw material. Based on our previous result, the existence of Al dopant would decrease the surface roughness of ZnO layer, reduce the grain size of ZnO particles, transmittance at visible light increase and also change the charge carrier density. Nevertheless, the highest efficiency was achieved for undoped ZnO/TiO₂ photoanode (η=0.67%). Based on current-voltage measurement data analysis (using diode model equation) the ideality factor (n) of device using undoped ZnO was smaller (n=2.96) than AZO 0.5 wt% and 1.0 wt% (n=∼4), indicate better quality of undoped ZnO/TiO₂ interfaces rather than AZO/TiO₂.

The thermophysical parameters of organic phase change material (PCM) of coconut oil (co_oil) have been studied by analyzing the temperature vs time data during liquid-solid phase transition (solidification process) based on T-history method, adopting the original version and its modified form to extract the values of mean specific heats of the solid and liquid co_oil and the heat of fusion related to phase transition of co_oil. We found that the liquid-solid phase transition occurs rather gradually, which might be due to the fact that co_oil consists of many kinds of fatty acids with the largest amount of lauric acid (about 50%), with relatively small supercooling degree. For this reason, the end of phase transition region become smeared out, although the inflection point in the temperature derivative is clearly observed signifying the drastic temperature variation between the phase transition and solid phase periods. The data have led to the values of mean specific heat of the solid and liquid co_oil that are comparable to the pure lauric acid, while the value for heat of fusion is resemble to those of the DSC result, both from references data. The advantage of co_oil as the potential sensible and latent TES for room-temperature conditioning application in Indonesia is discussed in terms of its rather broad working temperature range due to its mixture composition characteristic.

Planar spring as a mechanical resonator is very important in designing an electrodynamic vibration energy harvesting application (EVEH) to generate output power with high efficiency. Generally, component of the mechanical resonator is a cantilever beam that is designed using one cantilever with an inertial mass placed cantilever tip. In this study, a planar spring which has four arms cantilever beam was designed and fabricated using an extra-thin FR4-PCB material with a total thickness of 130 µm. There are four types of planar spring that were designed and fabricated in this research to produce resonant frequencies at about 30, 40, 50 and 60 Hz with 1 mm width cantilever arm and various length of 13.5, 11.2, 9.8 and 8.7 mm, respectively. FR4 resonator is fabricated using technology LASER-cutting in order to obtain results precisely. The resonant frequency generated by the mechanical resonator is characterized using vibrator system with certain acceleration. The resonant frequency of the planar spring was obtained at a frequency where the maximum induced voltage occurs. The resonant frequency generated by each type of planar spring was obtained at 24.81, 34.24, 40.2, and 46.8 Hz with three conditions of acceleration of 0.02, 0.06, and 0,1g (g=9.8 m/s²).

Effect of re-annealing treatment in thermoluminescence response of thermoluminescent dosimeter (TLD) CaSO₄:Dy and CaSO₄:Dy with PTFE (Polytetrafluoroethylene) addition was investigated. CaSO₄:Dy was prepared by a co-precipitation method. The PTFE was added before re-annealing treatment which the mass ratio of CaSO₄:Dy and PTFE was fixed to 2:3. The re-annealing treatments of the samples were done at temperature 700 °C for 1 hr. The obtained samples were characterized using a Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) to observe the molecule bonding in sample and crystal properties, respectively. From the experimental results, it was observed that the thermoluminescence intensity of CaSO₄:Dy, CaSO₄:Dy re-annealed at 700 °C, and CaSO₄:Dy + PTFE re-annealed at 700 °C are 57.03, 75.15, and 1191.11 nC, respectively. The intensity of 700 °C-re-annealed CaSO₄:Dy increased significantly after PTFE addition.

In this work, an analytical expression is presented of electron transmittance through a potential barrier by applying a bias voltage with spin polarization consideration. A zinc-blende material was employed for the barrier in the heterostructure to calculate the transmittance, which depends on the spin states indicated as "up" and "down". The obtained transmittance was then employed to compute the tunneling current. It was shown that the transmittances are different for each state and asymmetric with incident angle. The polarization is positive for a positive incident angle of and negative for a negative incident angle. It was also shown that the tunneling current did not reach its highest value at an incident angle of 0° (z-direction).

In this study, we report an analytical calculation of electron transmittance and polarized tunneling current in a single barrier heterostructure of a metal-GaSb-metal by considering the Dresselhaus spin orbit effect. Exponential function, WKB method and Airy function were used in calculating the electron transmittance and tunneling current. A Transfer Matrix Method, as a numerical method, was utilized as the benchmark to evaluate the analytical calculation. It was found that the transmittances calculated under exponential function and Airy function is the same as that calculated under TMM method at low electron energy. However, at high electron energy only the transmittance calculated under Airy function approach is the same as that calculated under TMM method. It was also shown that the transmittances both of spin-up and spin-down conditions increase as the electron energy increases for low energies. Furthermore, the tunneling current decreases with increasing the barrier width.