Table of contents

Preface

The 2^nd international Tropical Renewable Energy Conference (i-TREC) 2017 has been successfully held on 3 – 4 October, 2017 in the beautiful island of Bali, Indonesia. The 2^nd i-TREC 2017 was proudly organised by Faculty of Engineering, Universitas Indonesia.

This conference aimed to promote research in the field of development of tropical renewable energy, to facilitate an exchange of new ideas in these fields, and to create a dialogue between scientists, professors, industries, and practitioners. The main theme of the 2^nd i-TREC 2017 was "Towards Tropical Renewable Energy Innovation and Technology Integration."

List of Advisory Board, Scientific Committee and Organizing Committee are available in this PDF.

List of Conference Photographs available in this PDF.

We would like to thank our sponsors, who have supported the 2nd international Tropical Renewable Energy Conference (i-TREC) 2017.

List of Sponsor Images are available in this PDF.

All papers published in this volume of IOP Conference Series: Earth and Environmental Science 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 paper presents the first attempt to investigate of natural zeolite for cooling adsorption application. Representative samples were collected from Bayah-Banten, Indonesia. As known that zeolites can be used as an adsorbent. Unfortunately, natural zeolite has many limitation, among them contains a lot of impurities. To improve the characteristic of natural zeolite, activation and modification should be conducted beforehand. Activation was conducted by reducing grain size (1-2mm), washed by aquadest and heated using microwave. While the chemical activation is done through acidification by adding HCl solution. Finally, the activated natural zeolite was calcined gradually initiated at room temperature to 150°C for 2 hours and then heating continued from 150°C to 300°C for 4 hours. The final zeolite activated product was characterized by X-Ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) and Transmission Electron Microscopy (TEM). The result showed that the morphology of the natural zeolte was cubic shave as observed by TEM and the surface area of activated natural zeolite is geater than the raw material.

A process optimization was performed in this study to obtain the values of the geometry and process parameters that provide an optimum average microalgae concentration in an internally illuminated bubble-column photobioreactor. A phenomenological model of the photobioreactor is used to simulate the process in the reactor. The model considers gas-phase mass balance and liquid-phase mass balances accompanied by the rates of CO₂ and nutrient intakes in liquid phase. The process optimization gives the values of the small and large cylinder diameters, the culture height, the inlet air flowrate, the CO₂ mole fraction in the inlet air and the initial microalgae concentration that promotes the microalgae growth to 0.773 g/L from 0.2 g/L for less than four days.

Vaccine is one of the biggest problem that happen in Indonesia. Almost 75% vaccine is frozen on shipment process from Province to healthcare in district. Vaccine usually is transferred using a vaccine box whose the temperature has to be maintained at 2-8°C. The newest technology of vaccine box uses adsorption cooling and solar energy to keep the cold chain. This technology is separated into 3 modules which are cooling module (contain zeolite and water), vaccine box, and solar heater. The cooling module using adsorption as the cooling process, where the adsorption makes a pressure drop and causes the decrease of the temperature. The decrease temperature will be used as source of the cooling in the vaccine box. After the zeolite in cooling module reach the saturation because of adsorption process, it has to be heated up using solar cooker as the media. The solar cooker collects the energy from the sun using the principle of greenhouse effect. This study aimed to analyze if the design of vaccine box using adsorption cooling system and 13x/c_acl₂ composite zeolite as the adsorbent is suitable or not for holding the optimum temperature for vaccines. From simulation using MATLAB, an integrated technical computing including computation, visualization, and programming, the vaccine box could reach temperature 5°C and can be maintained for 12 hours with COP is 0.146. For the desorption process, it needs heat 150 KW and 23 minutes to complete the process.

Adsorption cooling is the newest technology that can be used in the distribution of vaccines. The principle of adsorption cooling is applicable to make a new technology called portable vaccine cooler, using zeolite as the absorbent and heat energy to keep cold chain of vaccine which needs to be stored in temperature of 2°C to 8°C. There are many ways to heat the zeolite up. Instead of using fire that induces environmental pollution to heat the zeolite up, the authors choose to use solar energy as the source of the desorption process. The aim of this study is to support cooling module and get the best results of two types of solar heaters to be applied on cooling box. In this paper, performance prediction of two solar heater are simulated using ANSYS workbench, a platform which integrate simulation technologies and parametric CAD system. The result shows that the solar heater type 1 is better to use because it can heat the absorbent chamber up at the temperature of 109°C in an hour running, whereas the absorbent only needs the temperature around 70°C-80°C to make the process of desorption running perfectly.

Experimental study of heat transfer coefficient of single phase has conducted successfully. Technology to reduce energy consumption is important to be investigated, moreover with implementation of renewable energy. The study used natural refrigerant of propane as working fluid with heating process. The aim of the present research is to study near boiling single phase heat transfer coefficient on the micro channel of 500 μm diameter and 0.5 meter length. Variable of research are heat flux of 1 to 15 kW/m², mass flux of 297 to 1102 kg/m².s, and test section inlet temperature of 21 to 26°C. The experimental results showed single phase laminar-turbulence flow with Reynolds number less than 10000. Heat transfer coefficient of near boiling single phase flow is significantly affected by Reynolds number and Prantl number. Using the present experimental data, new correlation of Nusselt number is developed as a function of Reynolds number and Prantl number.

In this research, the effect of physical and chemical modifications of low-grade bauxite (LB) with particle size of 200 mesh were studied. Here, we demonstrate chemically technique to synthesize low-grade bauxite/CeO₂ composites using Ce(NO₃)₃.6H₂O with weight variations of 0.5, 1 and 2 g. The effect of Ce(NO₃)₃.6H₂O concentrations on BET surface area of prepared low-grade bauxite/CeO₂(₀₅) (ALB0.5), low-grade bauxite/CeO₂₍₁₎ (ALB1), and low-grade bauxite/CeO₂₍₂₎ (ALB2) composites were observed. The results showed the BET surface area of LB is 59.85 m²/g. After acid activation with 1M HNO₃, activated low-grade bauxite (ALB) has BET surface area of 101.6 m²/g. By chemically modification with Ce(NO₃)₃.6H₂O in concentration ranging from 0.5; 1 and 2 g, the BET surface areas were reduced in the respectively order of 94.5, 87.9, and 85.5 m²/g for ALB0.5, ALB1, and ALB2. With the increase of the Ce(NO₃)₃.6H₂O concentration, the BET surface area reduced compare to those found in the ALB. The acid activation treatment has significant effect compare to the chemical modification using Ce(NO₃)₃.6H₂O.

The catalytic conversion of biomass has been studied by using a conventional fixed-bed reactor. The mixed catalyst is prepared by impregnation method followed by calcination of the catalyst. The B₂O₃/γ-Al₂O3 catalyst composition used in the biomass catalytic conversion process is varied to study the effect on its product distribution. In addition, catalyst variations were performed to test the catalytic effect in producing the target products, so that the optimum catalyst composition to maximize the target products is known. The catalyst composition of B₂O₃ in the mixed catalyst used was 0%, 5%, 10%, 20%, and 25% wt. The use of B₂O₃/γ-Al₂O₃ mixed catalyst can convert the small oxygenate compounds produced at the thermal decomposition step of biomass into aromatic hydrocarbon compounds. In addition, other groups of compounds were also observed with different product distributions where the differences were affected by the composition of the mixed catalyst used. Experimental results show that addition of B₂O₃ content up to 20% wt gives the highest catalytic effect with the main product being aromatic hydrocarbons. The decrease in catalytic effect occurs with the addition of 25% wt B₂O₃ content.

Transportation infrastructure design must follow sustainability concept that requires stability in economic, social and environment, then sustains in the future. Therefore, this research aims to identify time travel, fare level, percentage spending on transport, waiting time, and availability of alternatives mode as sustainable transportation indicators that could be applied in rural and urban area at Karawang Regency, as developing district correspond to society welfare as a social theme variable in sustainability development indicators. This research also identifies existing commutes characteristics and benchmark of the sustainable transportation indicators to improve society wellbeing. This research applies quantitative methods by conducting survey to collect data from respondents. The instruments to obtain data in Karawang Regency are questionnaire form, and then collaborated with structured-interview. Spearman's rank correlation is employed as the quantitative method in order to conduct non-directional and directional hypothesis test. In conclusion, time travel, spending on transport, and fare level variables representing mobility, equity, and affordability have significant influence to experience wellbeing, and then they have negative correlation to social welfare as well. For that reason, time travel and fare level must be reduced to improve society wellbeing.

This research was conducted to investigate the effect of anode depth and conductivity of electrolyte solution on required energy for plasma generation in plasma electrolysis. The experimental parameters were composed of different depth of anodes (0, 15, 25, 45, and 65 mm) and various solution conductivity. The difference in electrolyte solution conductivities is presented by different concentration of Na₂SO₄ (0.01, 0.02, 0.03, and 0.05 M). A batch reactor (diameter 130 mm, height 190 mm) with tungsten electrodes (cathode diameter 6 mm and anode diameter 0.5 mm) was used by applying a continuous cooling system. Current was observed in various voltage (40 – 400 V) for 30 second in each voltage. Energy consumption for vapor formation and discharge plasma found higher at deeper position of anode. At higher conductivity of electrolyte solution, although energy consumption for vapor formation was observed lower, energy consumption for plasma discharged was found higher.

This research aims is to design a renewable energy power plant based on the renewable energy potential in Domas village. Domas is a coastline that has a wind speed is has the potential to develop a wind power plant with enough capacity that can be utilized economically; in addition Domas is also a centre of rice and rice husks producer. Economic activity as a farmers and milkfish breeders and this area is set to be minapolitan area of Serang district. The problem is many of the ponds is placed far from electricity, so it requires another alternative as a source of electrical. Aquaculture requires aeration and lighting to increase fish and shrimp production, to keep the oxygen content dissolved in water. Lighting are required starting at 6 pm to 6 am, and the aerators based on the shrimp and fish life cycle are required to be switched on from 5 pm to 6 am. Wind data is obtained from Homer, meteonorm and NOAA databases, which is then processed in Homer for optimization. Potential data of husk is obtained from ministry of energy and mineral resources of the republic of Indonesia (EMR) database for Serang regency in 2016. For 1 hectare of land with 1.5 tons of fish, total electricity needed 2.4 kWh per day for lighting and 13 kWh per-day for aerator, with peak of 0.385 kW and 1.9 kW. By using the Aeolos 500 wind turbine as non-dispatchable resource and biomass generator as a dispatchable resource, a simulation is performed to get the system that produces the lowest LCOE (Levelized Cost of Electricity) and highest renewable energy (REN) factor for wind turbine. The recommended system is 2 kW Biomass Generator, 10 kW Inverter, 10 kW Rectifier, 24 Battery Trojan L18P 360 Ah capacity with 8 units of Aeolos 500 array. With economic LCOE $0.445 / kWh, and 82.2 % REN factor for wind turbine.

Loop heat pipe is a promising thermal control system, the same as a heat pipe, to realize the efficient release of heat from electric appliances. It is suitable for applications in electronics that have higher power density. Meanwhile, the heat pipe loop (LHP) can also be considered for adoption in the manufacture of solar hot water systems, due to its unique features such as effective thermal conductance and flexible design embodiments. However, the start-up problem of the LHP and transport distance and higher heat release capacity is still existed influencing the operating stability of the device. Base on the problem, this study focuses to carry out work on the developing a novel LHP system in order to provide a robust solution for significant enhance the ability energy transfer. This novel LHP is a conventional LHP that was modified by adding a diaphragm pump to accelerate the fluid transportation (called as hybrid loop heat pipe, HLHP). The pump is installed on the liquid line complete with a reservoir. It will work passively using the wick capillary pressure when there is no sign the occurrence of dry-out. In another hand, the pump was only activated when the evaporator temperature tends increased extremely because of the failure of start-up. The experimental result showed that installed diaphragm pump in LHP modified system was able to prevent the occurrence of dry-out and significantly reduced the evaporator temperature. This study will contribute to energy savings and the utilization of renewable energy.

In this research, ozone decomposition has been synthesized based on copper oxide (CuO_x) with granular activated carbon (GAC) as a support catalyst, being used as ozone decomposer in effluent gas emissions of industries that use ozone. Therefore, catalysts were made as a mask filter to decompose ozone. CuO_x was impregnated to the surface of GAC by using copper carbonate (CuCO₃) as precursor and then calcined to release carbon dioxide with temperature of 300 °C for 1 hour. Size of activated carbon and loading percentage of copper oxide to the support were varied to get the optimum value. The quality of a catalyst such as pore diameter and surface area are characterized by BET, the cross-sectional surface of the catalyst and the catalyst elements composition are analyzed by X-ray spectroscopy (SEM-EDX) and X-Ray Fluorescence (XRF), while CuO_x composition and crystal phase are analysed by XRD. Mask filter, which contained catalysts for ozone decomposition, was tested using a fixed bed reactor at room temperature and atmospheric pressure. Results of the catalytic conversion were tested using iodometric method. Activated carbon with smallest diameter (60 - 100 mesh) and highest loading percentage (2 %-wt) showed the highest activity which the ozone conversion to oxygen reached 100%. Amount of CuO_x on the support also determine the efficiency of catalyst due to appropriate amount of CuO_x probably maintain the morphology and crystal phase of the catalyst.

Investigation of catalyst for ozone decomposition was carried out by using zinc oxide (ZnO) catalyst and granular activated carbon (GAC) support. Ozone needs to be decomposed because it is harmful to human and can lead to death. Before GAC was used as a support, GAC was pre-treated using chloride acid (HCl) and sodium hydroxide (NaOH) to remove impurities. ZnO was impregnated onto the surface of GAC by using zinc carbonate (ZnCO₃) solution as precursor and then calcined at 300 °C to decompose carbon dioxide (CO₂). Size of GAC and loading percentage of ZnO were varied to get the highest catalytic activity. Size of GAC was varied between 18 – 100 mesh and loading percentage was between 0 – 2%-w. The morphology, composition, and crystal phase were characterized by BET, SEM-EDX, and XRD method. From XRD method, crystal phase of catalyst was changed from ZnCO₃ structure to ZnO when calcined with exact temperature. Ozone decomposition was performed at room temperature and atmospheric pressure using fixed bed reactor. ZnO/GAC with smallest size (60 – 100 mesh) and highest loading percentage (2%-w) showed the highest activity which the conversion reached 100% for 30 minutes. ZnO/GAC with smallest size and highest loading percentage had the largest surface area and the most active sites to decompose ozone.

Daily electrical energy consumption is a key parameter to determine balancing electricity supply and demand particularly in remote area where is not yet being electrified. The absence of daily electrical energy consumption data is a constraint for developing microgrid systems based on renewable energy. The purpose of this study is to improve electrical energy consumption model with adding some variables such as family income and family expenses, the number of family members and the load factor as independent variable, and electrical energy consumption assumption as dependent variable. Principal Component Analysis (PCA) method is used to find the relationship between independent and dependent variables. The electric energy consumption model Y = (0.69) + (1.77e⁻⁷xA₁) − (1.54e⁻⁷xA₂) + (0.037xA₃) + (7.45 xA₄), with determination factor (R-Square) is 97%.

Indonesia has a rich deposit of nickel. However, laterite in Indonesia has not been treated to its full potential. This happens because the refining process of lateritic nickel ore has a high cost, triggered by the amount of energy required and the complexity of the separation process. It needs pre-reduction to make the ore more easily to be reduced and increased the metal content so that it can maximize the nickel refining process and minimize the energy usage. One method of pre-reduction is carbothermic reduction. This research study the effect of temperature variation on the results of the carbothermic reduction of laterite ores using palm kernel shells as the reducing agent. The reduction process was done by heating the # 270 mesh lateritic ore and palm kernel shells with a mass ratio of 1: 4 for 60 minutes in the melting furnace at the temperature variations of 700, 800, 900 and 1000°C. The result of the reduction was then tested using XRF and XRD. Based on the calculation of % recovery, the optimum temperature for reducing the laterite ore with palm kernel shells for 60 minutes was 800°C which the content of NiO as much as 2.68%.

Indonesia has many valuable mineral resources, such as lateritic nickel ore. Today, the world demand of lateritic nickel continues to increase. This is an opportunity for Indonesia to develop its potentials in the nickel processing industry. To perform nickel reduction process, reducing agents such as natural gas and coal are needed. In this study, the use of a reductant from palm kernel shell waste as a coal alternative energy in order to reduce the use of fossil fuel which limited availability and cause environmental pollution, being a focus of this research. The purpose of this study is to determine the effect of palm kernel shell as a reductant in lateritic nickel reduction process, using mass ratio variable between mass of nickel ore and reductant. The mass ratio between nickel ore and reducing agent used in this study are 1:1, 1:2, 1:3, and 1:4, with the temperature of reduction in 800°C for 60 minutes. To observe the results of this experiment, the sample characterization was carried out using XRD and XRF. XRD data showed the presence of silica (SiO₂), iron oxide compounds such as maghemite (Fe₂O₃) and magnetite (Fe₃O₄), also compounds from reduction of lizardite such as forsterite (Mg₂SiO₄) and liebenbergite (Ni₂SiO₄). The results of XRF analysis showed improvement of Ni recovery in line with the addition of the mass of reducing agents.

Most of the time, coconut shells from the coconut farms have not been used but for charcoal purpose. In this work, the charcoal from the coconut shells was converted into an activated carbon and used it for the development of lithium ion battery. The development was begun by firstly synthesizing LiFePO₄ (LFP) through a hydrothermal route using stoichiometric amounts of precursors LiOH, NH₄H₂PO₄, and FeSO₄.7H₂O. The as-synthesized LFP was then mixed with variation of vanadium concentrations and a fix concentration of the carbon pyrolyzed from the coconut shells. X-ray diffraction (XRD) was used to characterize the crystal structure, whereas a scanning electron microscope (SEM) was used to characterize surface morphology of the composite. The characteristic of the composite was further examined an electrochemical impedance spectroscopy (EIS) for the conductivity. The XRD results showed that the LiFePO₄/V/C has been formed successfully with an olivine structure. The SEM results depicted an agglomerate morphology but most of LiFePO₄/V particles have been coated by the carbon. The EIS results showed conductivity values of 1.3387×10^-2 S/cm, 1.184×10^-3 S/cm, 1.7241×10^-3 S/cm, and 6.6423×10^-4 S/cm for the LFP/C-0V, LFP/C-3V, LFP/C-5V, and LFP/C-7V samples, respectively. The performance test indicated that coconut shell has a great potential as a cheap carbon resource for the development of lithium ion battery cathode.

The present study reports about the catalytic degradation of methylene blue (MB) by sodium borohydride (NaBH₄) in presence of silver nanoparticles (Ag NPs) as catalyst. Ag NPs was produced from green synthesis method using aqueous Imperata cylindrica extract. Formation of Ag NPs from the synthesis was confirmed by using UV-visible spectroscopy with the appearance of surface plasmon (SPR) bands around 427 nm. The agglomeration in microstructure of biosynthesized Ag NPs was revealed by field scanning electron microscope (FESEM).The synthesized of Ag NPs showed five diffraction peaks at 2θ values of 38.62°, 44.51°, 64.84°, 77.68° and 81.96° which corresponds to the (111), (200), (220), (311) and (222) planes of face-centred cubic. Energy dispersive X-ray analysis (EDX) revealed signals at the energy of 3 keV which indicates the presence of elemental silver that contributed to 68.44 weight % of the analysed sample. Upon addition of biosynthesized silver nanoparticles, the degradation of MB increases up to 92.06% within 14 min.

Hydrogen has been considered as promising energy carrier that can be produced from renewable resources, such as biomass through gasification. This process results in producer gas containing CO, CO₂, H₂, N₂, and CH₄. The conventional enhancement of hydrogen is typically conducted using several unit operations such as water gas shift reactor (WGSR) and separation unit such as Pressure Swing Adsorption (PSA). Process intensification offers a new method to integrate both WGSR and separation unit into single membrane reactor. This research aimed to investigate the influence of dynamic operation on membrane reactor performance. The steady state fixed bed reactor and membrane reactor were used as base case to judge the performance of dynamic membrane reactor. The water gas shift reaction over Fe₂O₃/Cr₂O₃/CuO was carried out at 350°C and 1 atm by varying the feed composition and gas residence time. The feed composition ratio of H₂O/CO consisted of 2 and 3 on mole basis, while the gas residence times were 1.2 s and 2.3 s. The membrane reactor consists of shell and tube sides made of Pd/Al₂O₃ material with technical specification of 10 mm inner diameter, 20 μm Pd thickness supported by alumina, and 10 cm reactor length. The compositions of the feed gas and products were measured using gas analysers such CO gas detector (Bacharach PCA^® 3) and H₂ gas detector (Cosmos XP-3140). The dynamic operation was performed following the square wave perturbation of the feed gas at switching time of 15 s. The experiment results showed that increasing the feed composition ratio and gas residence time increased the conversion of CO and hydrogen production in the fixed bed reactor and membrane reactor. Higher production of hydrogen also improved the recovery of hydrogen in membrane reactor. The use of membrane reactor increased significantly the conversion of CO when compared to fixed bed reactor. Moreover, the dynamic membrane reactor would give much better performance in term of CO conversion and hydrogen recovery. The stability of the Pd/Al₂O₃ membrane reactor was proven for at least 10 h operation.

Biodiesel is an alkyl ester compound of fatty acids prepared from a source of naturally renewable triglycerides and used as diesel engine fuel, commonly made through the process of esterification or transesterification. In its application and storage, biodiesel is potentially damaged by oxidation reaction due to internal factors (high unsaturated fatty acid content) and external factors (air, heat or light) resulting in changes of the characteristics and quality of biodiesel. In order to maintain the characteristics and quality of biodiesel to conform to established standards, it is necessary to add antioxidants that can inhibit oxidation reaction in biodiesel. In this study, pyrogallol antioxidant is added to the biodiesel of palm oil with various concentrations and storage temperatures. The observed biodiesel parameters during the storage period are those that can represent oxidation such as changes in kinematic viscosity, density, acid value, and iodine value. The results showed that the addition of pyogallol antioxidant can inhibit the oxidation reaction in biodiesel. The use of antioxidant with a concentration of 0.1% at storage temperatures of 30°C and 60°C is known to retain the characteristics and quality of biodiesel during storage from damage caused by oxidation reaction.

Adsorbed natural gas (ANG) is a natural gas storage technology, which is potential to transport natural gas in small and medium quantity. The objective of this study is to determine the techno-economic feasibility of ANG technology for flare gas to consumers around flare gas sources. The method is process simulation, economic calculation and optimization with variables being ANG selling price, flare gas price, and the percentage of capital financing by the government. The process simulation shows that the ANG product is in the range of 2.07 MMSCFD – 2.97 MMSCFD. The economic calculation results in the interest rate of return of less than 10%. With optimization, the IRR increases to more than 20%.

The characteristics of activated carbon pyrolyzed from rice husk used in the synthesis of LiFePO₄/V/C for the development of lithium ion battery cathode has been examined. The synthesis was begun by synthesizing LiFePO₄ (LFP) via hydrothermal route using the precursors in stoichiometric amounts of LiOH, NH₄H₂PO₄, and FeSO₄.7H₂O. The assynthesized LFP was then added with variation of vanadium concentrations and a fix concentration of the carbon pyrolyzed from rice husk to form a composite of LiFePO₄/V/C. The composites were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and electrochemical impedance spectroscopy (EIS). The XRD results showed that the LiFePO₄/V/C has been successfully formed whereas SEM results showed a difference in morphology of vanadium and activated carbon addition. The EIS results showed that the conductivity of LiFePO4/C-0 wt.% V is 1.0196×10^-2 S/cm, LiFePO4/C-3 wt.% V is 1.0302×10^-2 S/cm, LiFePO4/C-5 wt.% V is 6.1282×10^-3 S/cm, and LiFePO4/C-7 wt.% V is 8.3843×10^-3 S/cm. The best performance for lithium ion battery cathode was given by LiFePO4/V/C at 3 wt.% vanadium. This result indicated that rice husk can be used as a cheap resource for activated carbon in the development of lithium ion battery cathode.

Synthetic dyes are often used for textile dyeing process. The dye wastewater containing hazardous materials, toxic, and also harmful to the environment. Among the existing technologies,photodegradation using semiconductor catalyst is a promising alternative method. However, the weak adsorption capacity of photocatalyst is an issue for photocatalysis process. To overcome this lack, photocatalyst material needs to combine with an adsorbent. The composite was synthesized by combining the function of activated carbon as adsorbents and TiO₂ as a catalyst. The objective of the study was to synthesize a composite of activated carbon and TiO₂ through impregnation method. The activated carbon-TiO₂ composite produced was characterized to determine the surface morphology and the elements contained in the composite by using SEM/EDX. The composite activity to photodegrade various concentrations of Procion red, as a model of synthetic dye, was also investigated. To compare the activity of activated carbon-TiO₂ composite in degrading Procion red, different conditions were applied by using UV lamps, sunlight irradiation, and without irradiation (darkroom). The activated carbon-TiO₂ composite was able to photodegrade of Procion red by UV light irradiated at optimum wavelength 530 nm. The highest photodegradation percentage of 58.9% and 71.7 % were obtained when using the activated carbon-TiO₂ composite ratio of 3:7 and 1:1, respectively.

Global energy issue is no longer a new topic. The expansion of energy production proven to show significant influence is the fossil fuel modification by blending it with liquid renewable fuel, such as bioethanol. Bioethanol must achieve fuel-grade standard to qualify as gasoline, one of the specification is to have moisture content of 1.0% v/v or less, as regulated by ASTM D4806. This parameter is a challenging one to achieve, because water-ethanol mixture will encounter the azeotrope phenomenon when the mixture undergoes a common distillation process and reach 95.6% v/v of ethanol. One of the dehydration method that use less energy is adsorption. One of the efficiency consideration of bioethanol dehydration with adsorption is its adsorption capacity. Adsorption capacity is influenced by the material of adsorbent, operational temperature and time. The material being tested in this research is poly vinyl alcohol (PVA), zeolite, and activated carbon. This research will analyze the dependency and influence of mixture's initial concentration and operational temperature condition towards the final concentration of ethanol and adsorption capacity utilizing a Langmuir model. The result of this study showed that the activated carbon has the highest parameter capacity, which is twice as much than zeolite and three times larger than PVA. Whereas the result of selectivity study between the three prove that zeolite has better selectivity.

In order to utilize biogas, hydrogen sulfide/H₂S impurities reduction is needed to maximize methane/CH₄ content. Although H₂S amount is relatively non-dominant, its presence can trigger corrosion, and is harmful to health and environment. Steel wool can be used as adsorption media to reduce H₂S content. This study was conducted to identify the characteristics of steel wool and H₂S concentration reduction efficiency. Biogas was flown to a PVC column (2 inches diameter) containing steel wool. The results showed that steel wool media contain active elements of Fe and Zn which are spread evenly on the media surface with a total amount of 97.5% mass. The concentration of H₂S at inflow ranged from 68 to 111 ppm with the outflow of 21.2-0 ppm, and the temperature in the system varied between 29-33 °C. Optimal H₂S removal efficiency reaches 97% in average, obtained at 100 cm column height and flow rate of 0.1 L/min. It can be concluded that the steel wool media has high content of active element and can reduce H₂S content in biogas at ambient temperature condition.

The intensity of solar radiation received by the PV Module can be maximized by installing a PV module with a slope angle. Besides, when the intensity of solar radiation increases, the surface temperature of PV also tends to increase, which decrease PV power output. Temperature Surface can also be reduced by the additional glazing with low emissivity. By knowing the appropriate angle of inclination and the glazing addition, it will able to maximize light energy (photon) and minimize heat energy received by PV surface. So the system can obtained maximum output power and minimum surface temperature. The heat transfer can be determined by analyzing the thermal resistance occurring from the sun down to the PV surface and from the PV surface to the surroundings. The test was performed using a commercial PV module with 180 Watt Peak power, where the test results were discussed and presented. The results shown that PV module facing North with slope angle 30° has the highest output power. The heat release was large enough compared to the other slope angle variation. Besides, the addition of glazing system decreases the output power due to its medium transmittance about 70% and the temperature of PV module also decrease due to low emissivity about 0.26.

One way to save electrical energy is by directly reducing the energy consumption and using materials that able to absorb heat. The best material in absorbing heat is paraffin. Paraffin is a group of organic Phase Change Material (PCM) which has high latent heat. Adding nanoparticles to the paraffin is expected to increase the latent heat of nano-PCM. The research aims to find out the thermal properties of nano PCM based paraffin and engineered to improve its latent heat. In this research, PCM material used is paraffin with Fe₃O₄, CuO, TiO₂, and ZnO nanoparticles are added. Nano – PCM is synthesized using sonification methods with variations of 5, 10, and 15 wt%. Latent heat of thermal properties and a melting point of paraffin nano-PCM are measured using Differential Scanning Calorimetry (DSC). The results show the latent heat of paraffin nano-PCM has increased by 20.67%, 78.89%, 7.5%, and 20.17% for the addition of Fe₃O₄ (5 wt%), CuO (10 wt%), TiO₂ (15 wt%), and ZnO (5 wt%) respectively. The better nano PCM in storing latent heat is paraffin-CuO at a mass fraction of 10 wt%. Meanwhile, the addition of nanoparticles has no significant effect on the melting point. These results showed that paraffin based nano-PCM is an excellent thermal energy storage.

Noisy Time Domain (NTD) model and behaviour of male dolphin using the underwater camera, and also comparing between sound and time from the spectrum. Collecting data was taken at the Safari Park of Cisarua Bogor in Indonesia, in show pool. Data at the show with replications 1,2, and 3 has a salinity of 29 ‰. Sound whistle 3 is 28.03 dB with the frequency interval of 14.64 kHz-16 kHz. The results showed that salinity in the show pool with replication 1,2, and 3 has salinity value that is equal to 30 ‰. F-test at the show pool has heterogeneous value. Treat at the show pool has a value of P <0.001 and P <0.001. Noisy Time Domain have differences with each other and have a lot of different sound patterns and detection of energy from power spectral density (PSD) signal.

After Fukushima Dai-ichi nuclear power reactor accident, spent fuel in spent fuel storage pool (SFSP) became an important thing to pay attention to, due to its decay heat release. If station blackout occurred, the active system for SFSP cooling system will experience malfunction to remove the product of decay heat. To keep spent fuel safe, heat pipe as passive cooling system device can be used to remove spent fuel decay heat even if the active cooling system failed. Heat pipe with 6 m on length will be proposed as apassive cooling system in SFSP. For that, it is necessary to analyze the effect of Graphene nano-fluid as heat pipe working fluid. The objective of this research is to know the effect on Graphene nano-fluid to enhance the heat pipe thermal performance and to know the heat transfer phenomena inside the heat pipe based on Graphene nano-fluid. Graphene nano-fluid with 1% weight concentration was used as working fluid with filling ratio of 80%. The experimental investigation is conducted with varying the evaporator heat load of 1000, 1500, 2000, and 2500 W. Water as coolant flows in thecondenser with aconstant volumetric flow rate of 8 L/min. The experiment results show that there was anovershoot, zigzag and stable phenomena inside the heat pipe. The thermal resistance of heat pipe is obtained at 0.015 °C/W. The use of Graphene nano-fluid as working fluid can enhance the heat pipe thermal performance significantly and can be used as an alternative working fluid in heat pipe for thepassive cooling system in SFSP of nuclear power plant.

More than 17% of people in remote areas of Indonesia still do not have electricity. With the abundance of water potential in Indonesia, hydro pico is consideredas the right solution because it has cheap investment and operational cost. The breastshot waterwheel is a suitable turbine that can be applied because it does not affect the garbage in the water. Characteristic of the breastshot waterwheel especially effect of bucket numberon performance have been study in this paper. CFD method isused to evaluate the flow field and explain the effect of the number of the buckets on the waterwheel performance qualitatively. The turbulent model used is k-ε. Simulations were performed with the number of buckets 11, 12, 13, 14 and 15. Analysis using ANOVA block design explains that there is a relationship between the number of buckets to the generated power (F₀ > F_0.01,2:8). From the analysis, the wheel with the number of bucket 13 produces more stable power than other buckets. This is because the shape of the radial blade is not so steeply upward that the weight energy of water and kinetic energy can be utilized maximally.

Solar PV power plant investment in Indonesia is one amongst the alternative for electricity supply to maintain electrical reliability supply and to maximize local energy potential for remote areas. An objective approach in terms of ability and willingness to pay of the community at study location becomes the basis for revenue potential calculation of on this study. Assessment of investment feasibility including economic incentive calculation becomes more important if incentive is required in order to improve return of investment and at the time to provide good quality of energy supply at the lowest possible cost. Community characteristics data on study location is processed using statistical methods and micropower optimization simulation to generate PV system specification and all component needed to invest. To increase the return of investment the economic incentive scenarios are generated to provide alternatives to optimize the economic feasibility while maintaining the technical feasibility based on the ability and willingness to pay of the community, and not inflicting financial loss to the incentive giver. The results of investment feasibility calculation, with various scenarios built for investment alternatives, PV investment is economically feasible based on common investment analysis criteria such as expected NPV (net present value), IRR (internal rate of return), and PBP (payback period).

Plastic waste has been a problem in waste treatment.The growth of plastic waste is increasing especially in Jakarta and needs more serious attention in waste processing. To convert polystyrene to be liquid much heat energy is needed. In this research, pyrolysis is used as the method to process polystyrene to be aliquid product. The objective of this research is to obtain the characteristics of the heating process, and the properties of the liquid product. This liquid can be used as a fuel. Fixed-bed reactor with SUS 316L as the base material was constructed to decompose the polystyrene using an electric heater, which was controlled using Digital PID controller. Power sensor was mounted in the electrical circuit to monitor the power that entered to the heater and recorded using data acquisition. The reaction temperature was varied from 350 °C – 550 °C. No sweep gas injected into the system. The vapor flows naturally based on their partial pressure. The temperature of cooling water was varied into two conditions, water ambient temperature, and cold water. To condense pyrolysis vapor to be liquid oil, the double-pipe condenser was constructed. The thermocouples were installed at many points of the system to monitor temperature change in the system. The maximum liquid yield was obtained at reaction temperature 500 °C with cooling water temperature at 16.59°C.The operating temperature Below 500 °C will produce more wax, and above 500 °C will produce much gas. The liquid can be applied as fuel with heating value 43.83 mJ/kg, density 0.89 g/ml and0.78 cSt of kinematic viscosity.

Determination of the characteristics of rice husk (RH) with plastic bag (PB) mixture as a source of energy is carried out in pyrolysis study. Test characteristics of RH with PB mixture is performed by using a thermogravimetric analysis at temperatures from 30 - 800°C, heating rate of 10°C/min, and nitrogen flow rate of 50 ml/min. The dehydration process occurs at temperatures from 40 - 100°C, while for thermal degradation at temperatures from 200 - 340°C, 400-500°C, and 580 - 6700C. Activation energy and calorific value of RH with PB mixture increase significantly with the addition of 10%, 30%, and 50% PB in RH. It is concluded that pyrolysis characteristic of RH with PB mixture is better as fuel for power generation if compared with its original state.

Indonesia has a high production of vegetable oils. Coconut oil and palm oil are vegetable oils that can be source of raw material in Industry. The purpose of this research is potential use of coconut oil and palm oil as raw materials of alkanolamide in alkaline condition. Alkanolamide is produced from the reaction between triglycerides and diethanolamine. Phosporic acid is used as a solvent for the purification of alkanolamide from its mixture with glycerin. So it is expected that alkanolamide produced has a high purity and the resulted alkanolamides have dispersant and detergency properties that are widely used in various industries. The amidation reaction between triglyceride and diethanolamine was mixing in a glass batch reactor for 2 hours using potassium hydroxide catalyst (KOH) 1% (w/w). The temperature reaction was 125 °C. The second step is purification of alkanolamide. The operation condition is preferably performed at 82 °C. The synthesis of palm oil in this study is constrained because it is easily oxidized and the viscosity was higher than coconut oil. So this research is focused on using coconut oil as raw material. From the purification analysis, resulted 85% of alkanolamide (top layer) and 15% glycerine (bottom layer). From FTIR analysis, The amide group (C=O) is formed at a wavenumber of 1618,34 cm^-1 for alkanolamide from coconut oil and 1617,45 cm^-1 for alkanolamide from palm oil. GC-MS analysis resulted the compound of diethanolamide laurate with the greatest quality percentage of 93% and the largest percentage of 31, 20%.

In this study, MES surfactant was synthesized from waste cooking oil (WCO) which can lower the synthesis cost and represent efficient utilization of waste.MESis an eco-friendly anionic surfactant, which can be used for our detergent application. The purpose of this study was to obtain optimum MES surfactant from purification of WCO. WCO is purified first to reduce high impurities and free fatty acid (FFA). Purification steps of WCO consist of filtration to separate food residues, neutralization with various concentrations of NaOH solution13%;14%;15%;16% and bleaching with activated carbon 7.5% (wt. % of oil). After purification followed by trans-esterification process with variation of mole ratio oil and methanol 1:8; 1:9; 1:10 then synthesized MES surfactant with sodium bisulfite (NaHSO₃) as sulfonating agent. Neutralization results showed high reduction percentage of FFA was 31.31% for 15% NaOH solution; bleaching results showed reduction percentage of FFA was 20.27% and WCO color was originally dark brown to be light yellow. The results of trans-esterification showed highest yields 94.15% for mole ratio of oil and methanol 1:9 and sulfonation results will be described further in this paper.

Lateritic nickel ore is one of the biggest mineral resources in Indonesia. This ore has a huge potential, i.e., economic value for processing and purification, however requires high energy in the separating of mineral and gangue minerals, in addition the production cost is also high. Therefore, to resolve the problems, a pre-reduction stage called carbothermic reduction process is carried out. Carbothermic reduction process is usually used for saprolite-type lateritic nickel ore which needs a reductor for the reduction reaction to produce pure nickel. Common reductors used are coal and cokes. In this study, a development on carbothermic reduction of saprolite, type of lateritic nickel ore using biomass reductor palm kernel shell, is proposed. The lateritic nickel ore used is obtained from East Halmahera and the palm kernel shells are obtained from the waste of palm oil plantation at Palangkaraya, Central Kalimantan. The purpose of this study is to find out the effect of reduction time variation on carbothermic reduction result of lateritic nickel ore with constant temperature and mass ratio value. Reduction time variation used in this study was 1, 2, 3, and 4 hours. All samples were tested at 800°C with the mass ratio of 1:4 (lateritic nickel ore : palm kernel shell) which were put into a crucible and then the carbothermic reduction process was done in a melting furnace. Peak formed on the XRD pattern showed that the process was able to reduce hematite or magnetite to wustite within one hour. XRF and recovery calculation results showed that the reduction time of one hour is the optimum time because nickel oxide (NiO) content was the highest i.e. 2.68% compared to other time variation.

A good biocompatibility material such as Ti-6Al-4V is neededfor a dental application.However,Ti-6Al-4V has no antibacterial properties. Therefore Ti-6Al-4V is modified using anodizing methods to improve its anti-bacterial properties. One of the most influential factors in the anodizing process is the type of electrolyte solution. The influence of electrolyte solution based on glycerol and ethylene glycol to morphology and crystallinity of TiO₂ nanotubes is studied. Smoothing and chemical polishing was performed against the Ti-4Al-6V plate. Then, the anodizing process for each plate in glycerol and ethylene glycol solution was done for 2 hours and 50 volts. Calcination was carried out for 3 hours at a temperature 500°C. FESEM-EDX and XRD were employed to analyze the surface morphology and crystallinity of TiO₂ nanotubes. Viscosity of the electrolyte solution influenced surfacemorphology. Calcination process influenced crystallinity of TiO₂ nanotubes.The average tube diameter and thickness from glycerolelectrolyte solution was 135.45 nm and 26.27 nm, while ethylene glycol was 68.52 nm and 35.62 nm respectively. The size of anatase crystal was 34.95 nm for glycerol and 44.77 nm for ethylene glycol.

Volatile organic compounds (VOC) such as benzene are among the most dangerous air pollutants emitted by chemical industry stacks, as they may contribute to environment and health issues. Lean catalytic oxidation of benzene has been considered as most proper method to abate it from the flue gas. This work developed nano-based copper oxide catalysts for lean oxidation of benzene. The aim of this study was to evaluate the activity performance of the nano-based copper oxide catalyst and compare to commercial catalyst. On the basis of the commercial catalyst, this study was also aimed to determine the reaction rate and its kinetic parameter. The oxidation of benzene was conducted in a fixed bed reactor at 300°C, 1 atm, and GHSV of 15,000 h⁻¹. The concentration of benzene in the feed and product were measured using online gas detector (Cosmos Gas Detector). The catalyst activity of nano-based copper oxide catalysts showed 20-30% conversion of benzene, while for commercial catalyst showed 86%. The reaction rate determination for first order reaction of benzene indicated that the activation energy was 48 kJ/mol with Arrhenius constant of 3×10⁴ s⁻¹.

Many of Rumah Gadang of Minangkabau in West Sumatra has strived through many years of extreme tropical climate. Through times this type of vernacular house has remarkably endure and stay, hence the increasing numbers of maintenance cost. One family generation to its next, as many other normal family houses may have experienced, the annexation phase (adding spaces) of living is inevitable. As Rumah Gadang design has been considered as one model of eco-tropical architecture fine example, its annexation could make the green compactness of its majectic design changed. This research analyzes major typical modifications and changes that could happen to Rumah Gadang's original design. Field research was conducted direct to its site's origin in West Sumatra. Its actual and recent plans (after annex) are documented to study the basics and its upgrading modification tendencies. This information then could become the base for further research on exploring the local wisdom, its traditional building values, material development and changes, and also its future endurance.

The increase of greenhouse gasses effect is one of the causes of climate change. The use of vehicles with fossil fuels is one of the contributors to pollution and global warming. Another reason why dependence on it should be reduced is the lack of Indonesia's petroleum reserves compared to other OPEC countries. Researchers are trying to anticipate this by developing electric vehicles capable of operating without pollution. Implementation of electric vehicles has begun with the electric train, tram, electric bus, and others. Vehicles with rails get electricity supplies from the grid along the tracks, but the type of freely moving vehicle without a rail requires another way to get electricity supplies. Electric vehicles with power storage (battery) have an advantage in the roaming area if supported by proper recharging techniques. In electric vehicles, the battery is recharged by the direct charging process or swapped with other one (swapping). If the vehicle has high mobility, such as public transport (bus) then the shortest charging time may be very important.

One of the promising solutions for energy management is thermal energy storage. Beeswax is type of wax from beehive which can also be performed as thermal storage with high latent heat but it has low thermal conductivity. On the other hand, multi-walled carbon nanotubes (MWCNTs) are known as an advanced nanoparticle which has high thermal conductivity. In this research, modification of Beeswax/Acid-treated CNTs (A-CNTs) composite was conducted in order to determine shifting on its structure and thermal performance. MWCNTs were functionalized with strong acidic mixture by ratio 3:1 of H₂SO₄ and HNO₃ becoming A-CNTs. Impregnation method was being used to shape the composite with mass ratio of 5% A-CNTs. Several tests were conducted, functional group formation was determined by Fourier Transform Infrared (FTIR) test and thermal performance was observed by Differential Scanning Calorimetry (DSC) test, and thermal conductivity test. Test results show that modification of stable Beeswax/A-CNT composite was successfully formed and indicate that with addition of 5 wt.% A-CNTs, the latent heat of Beeswax decreases 25% and significantly escalate the Beeswax's thermal conductivity by up to 84%. It supports that Beeswax is a promising solution for energy management system near in the future that is available abundantly and affordably.

Multi-hull ship had characteristics with complex geometry configurations. In the early stage design, multi-hull ship with proper configurations can be producing both minimum resistance and power consumption. Increasing number of hull as in pentamaran will increase frictional resistance, but total resistance can be reducing by decreasing wave making resistance with a slender hull form. With CFD tool used to examine minimum resistance with modified modelling of chine hull form on variation i.e. deadrise angles, waterline section of entrance angle and longitudinal section of stem angle. All simulations were conducted with fix separation on S/L 3/16 and Froude number up to 0.7. Comparison with the original hull form, chine hull form C35 II in deadrise 35° and angle of entrance 15° more advantageous with maximum resistance drag reduction 20.38%. The results of the study had been displayed in table and charts of chine pentamaran which having the smallest total resistance expressed in coefficient of friction and wave resistance.

Lithium-ion batteries are the most common type to be used as energy source in mobile phone. The amount of lithium-ion battery wastes is approximated by 200 – 500 ton/year. In one lithium-ion battery, there are 5 – 20% of cobalt metal, depend on the manufacturer. One of the way to recover a valuable metal from waste is leaching process then continued with extraction. Spent lithium-ion batteries will be characterized with EDX and AAS, the result will show the amount of cobalt metal with form of LiCoO₂ in the cathode. Hydrochloric acid 4 M, temperature 80°C, and reaction time 1 hour condition give out the best leaching efficiency for both Co and Mn metals, 88.54% and 89.28% respectively. For extraction, the best extraction efficiency achieved when feed phase pH is 5 for Co and 6 for Mn. This study will discuss the leaching and extraction process and compare the efficiency for both processes.

Loop heat pipes (LHPs) with Lotus-Type Porous Copper (LTP Copper) capillary wick are expected to be applied to battery thermal management systems for safe operation at high performance with a long service life. Sintered LTP Copper is a high permeability porous metal with an excellent capillary pumping characteristic. The objective of this work is to determine the performance of the battery thermal management system using LHP with sintered LTP Copper capillary wick experimentally. The experiment used two battery simulators made of aluminum. The heat generation of the battery was simulated using cartridge heaters. The LHP was made of 10 m OD copper tube, and the sintered LTP Copper capillary wick was placed in the liquid line. Water was used as working fluid with filling ratio of 50%. The evaporator section of the LHP was inserted between the battery simulators surfaces. A thermostatic bath was used to regulate the condenser cooling fluid temperature. K-type 0.3 mm thermocouples were used for temperature measurement, and a digital power meter was used to measure the electric power. Experiments were conducted with various heating power with the condenser cooling fluid temperature was kept at 28°C. At a heat generation of 20 W, the LHP was capable of maintaining the battery surface temperature below 50°C. At a heat generation of 40 W, the utilization of LHP with LTP Copper can reduce the average battery simulator surface temperature from 93°C to 65°C.

This paper presents the capacity of a heat exchanger with a plate heat exchanger model as evaporator and condenser to liquefy and evaporate R-134a refrigerant as the working fluid in a power plant system by operating an Organic Rankine Cycle (ORC) system using a scroll type expander. The evaporating and liquefying refrigerant as the working fluid uses hot water at a temperature between 40 °C - 80 °C and an evaporator inlet temperature at between 24.1 °C – 28.5 °C. The model design of the hot water production system is a combination of heat exchanger and heater with a shell and tube construction, where the heater is immersed in the heat exchanger. Experimental results show that the average revolutions of the turbine expander scroll is about 348.2 rpm and thermal efficiency between the evaporator and condenser as the heat exchanger ranges from 2 % to 8.5 %.

Vegetable cooking oils (VCOs) and used vegetable cooking oils (UCOs) can be considered as alternative fuels which will provide the household with low price fuel and may solve the problem of getting rid of waste VCOs. Their utilization as cooking fuel can bring numerous benefits not only for urban but also for rural communities in Indonesia. The paper focuses on characterizing VCOs and UCOs as fuels for the household cooking application using a modified pressurized cooking stove. Physical properties such as auto-ignition point, auto-ignition time, flash point, density and viscosity of VCOs play the vital role in the combustion. Some properties of these oils were measured and characterized according to ASTM standards. The oil was used directly as a fuel using in a design modified pressurized cooking stove. Adjusting the temperature of vegetable cooking oils used as fuel, it is possible to improve their combustion performance, thus reducing ignition time and incomplete combustion. The main target of the research is to determine the quality and performances of these oils combustion. The auto-ignition point for the several oils was determined to be as follows: UCO: 460 °C, crude VCO: 406 °C, fresh VCO: 405 °C and the peanut cooking oil did not auto-ignite. Crude VCO gave the shorter auto-ignition time than other oils within 30 s. The efficiency of the pressurized stove using UCO, crude VCO and fresh VCO as fuel were observed 23.65%, 25.99%, and 31.57%, respectively. The highest flame temperature of 942°C in these experiments was achieved by burning fresh VCO as fuel in this modified pressurized cooking stove. UCOs tended to produce luminous flames compared other oils.

The uncontrolled formation of free radical formation released to the air especially in the high urban area lead to resulting negative effect on the air quality. This condition is consequently made the human skin continuously contacts to those radicals and may cause a skin diseases. Therefore, one way to overcome this problem is to manufacture a soap formulation which provide a new function of its ingredient as radical scavenger or to keep the skin in health. Papain is a plant proteolytic enzyme for the cysteine protease enzyme which found naturally in papaya (Carica papaya) manufactured from the latex of raw papaya fruits. Proteolytic enzyme has a function which is able to break down organic molecules made of amino acids, known as polypeptides. In this research crude papain enzyme is developed into active ingredient of solid soap formulation with the antioxidant originated from fresh papaya to enhance the useful soap for human skin health. This study aims to produce a solid soap formula that is safe for the skin, meets the standard of SNI 1996 and tested the benefits in the addition of crude papain enzymes. The result showed that Formula IV is a formula soap that meets standard SNI 1996 and have highest antioxidant activity among other formulas indicated by the value of IC50 is 13,657 ppm. Compared soap with positive control (without enzymes) than negative control (with enzyme) has value of percentage dirt removal higher than positive control, it is 19% with measurement absorbance of wash water substrate and 32% measured by mass substrate after washed.

Polypropylene plastic (PP), which has higher hydrogen content compared to that in biomass, is potential to be used as a cheap hydrogen source for pyrolysis of biomass, such as corncobs, to remove part of oxygen content in the biomass pyrolysis oil. By charging these two materials, synergistic effects will appear that improve quality and quantity of bio-oil produced. The aim of the present work is to investigate possible mass interaction between biomass and plastic materials leading to the synergistic effects using slow co-pyrolysis. The experiment was performed in a displacement reactor. Feed composition was varied at 12.5%, 25%, 37.5%, 50%, 62.5%, 75%, and 87.5% weight of PP. This phenomenon was observed through expansion-contraction of the reactor prior to large mass decomposition of the reactor feed. In experiment involving biomass-dominated feeds, i.e. PP contents < 50% (regime 1), there was reactor bed contraction due to slight biomass decomposition followed by no-displacement of reactor piston. During the contraction, it is estimated, there was low velocity ejection of biomass volatile matter, while during no-displacement stage, there was a phase change of plastic granules to plastic melt. In experiment with plastic-dominated feeds, i.e. PP ≥ 50% (regime 2), the reactor bed underwent contraction due to phase change of plastic granules which reduced the bed volume, followed by bed expansion due to the swelling of biomass particles estimated in the presence of hydrogen bonding in the phenolic environment in biomass material. The last stage of co-pyrolysis in regime 2 was the bed contraction and it is predicted that there was high velocity gas ejection through the small pores which intensified interaction of biomass-plastic radicals in hydrogen-rich environment favourable for exerting synergistic effect.

Pipeline system as fluid transport is very commonly used. Thus, the drag reduction becomes very interesting to be studied because it is related to energy efficiency. One method of drag reduction is the active method by adding drag reduction additive agents such as surfactants, polymers, nanofluids, and fibers. The purpose of this study is to analyze the effect of coconut fiber on drag reduction by adding coconut fiber with varied concentration. The experimental was experimented by using circular pipe ID 38 mm with 1200 mm length. The test fluid was coconut fiber suspension with concentration 300, 500, and 1000 ppm. This study was conducted from low Reynolds Number until Reynolds Number about 25,000. In this research condition, the results showed that the drag reduction on circular pipe ID 38 was about 7.6% in the Reynolds Number about 25,000. The maximum drag reduction was for coconut fiber suspension with concentration 1000 ppm. The drag reduction increases with the increase of coconut fiber suspension concentration. Based on this research, it can be concluded that coconut fiber can be used as a drag reducing agent which save natural resources and environmentally friendly.

Green diesel is a second generation of biofuel that has a potential to answer the energy needs in Indonesia, also in the world. The reactions used to produce green diesel are hydrolysis and hydrodeoxygenation by using NiMo/Al₂O₃ catalyst. Hydrolysis will change the triglycerides in the raw material, which is waste cooking oil into free fatty acids (FFA) and then converted into green diesel through hydrodeoxygenation. Hydrolysis of waste cooking oil carried out at temperature of 200°C and pressure of 16 bar for 3 hours with water and oil volume ratio of 1:1. FFA product of hydrolysis is as much as 73.89%. For hydrodeoxygenation, variation in operating condition used are 375°C with pressure of 12 bar and 400°C with pressure of 15 bar. Characterizations of green diesel have shown that both of hydrodeoxygenation products have met the specifications of diesel, except the acid number with optimum operating condition at 400°C and pressure of 15 bar. These conditions with NiMo/Al₂O₃ activated led to dominant yield of 68.87% of diesel fraction, selectivity of 69.58%, and conversion of 82.15%.

Microalgae have the potential to be used as the raw material for biodiesel synthesis. One of promising microalgae species to be used is Chlorella vulgaris. However, in the process of biodiesel synthesis from microalgae needs to be optimized. In this study, optimization of biodiesel synthesis from wet and dry based microalgae Chlorella vulgaris has been studied. Optimization done by arranges the time of transesterification reaction. Transesterification reaction has been done using KOH catalyst. The reaction time was varied at 20, 40, and 60 minutes. From the results, the highest yields of biodiesel are obtained on the 40 minutes reaction time with biodiesel yield is 75% for wet based microalgae and 62.8% for dry based microalgae. Biodiesel from dry based microalgae Chlorella vulgaris composed by several types of FAME, including saturated FAME such as methyl myristate (4.48%), methyl palmitate (28.3%), and methyl stearate (17.1%), and also composed by unsaturated FAME such as methyl palmitoleate (11.1%) and methyl oleate (39.1%).

Microalgae are promising sources of biofuel due to its production capacity of lipid that can be utilized as raw material for biodiesel production, especially Nannochloropsis oculata and Chlorella vulgaris. The lipid produced can be converted into biodiesel through transesterification reaction using homogenous or heterogeneous catalysts. Heterogeneous catalysts are more advantageous than homogeneous catalysts due to its solid form that eases the separation of catalysts from the products. In this research, NaOH/zeolite heterogeneous catalyst is utilized with varying Na loadings in the zeolite to observe its effect towards the yield of biodiesel produced from N. oculata and C. vulgaris. The best result was obtained with Na loading concentration of 20.5%. The biodiesel yields obtained from the lipids are 83.5% from N. oculata and 98% from C. vulgaris. The biodiesels contain 47.15% of saturated fatty acid methyl esters from N. oculata and 56.41% from C. vulgaris.

Magnesium is one of the newly developed anode materials for seawater activated batteries. Anodizing is usually performed to expand the surface of anode materials which can improve the battery discharge performance. This work used Oxalic acid with concentration varied from 0.1 to 0.3 as an anodizing agent with electric potential varied from 1.5 to 6.0 Volt for an anodizing process. Electric potential used in the anodizing was varied from 1.5 to 6.0 Volt. Microstructure and corrosion behavior of anodized magnesium used in this work as battery anode and graphite as a cathode in 3.5% NaCl electrolyte solution were studied. Anodized magnesium in 0.3 M oxalic acid has the most uniform pores of microstructures than those anodized at other concentrations. Anodized magnesium at electric potential from 1.5 Volts tend to has higher value of potential (Ecorr = -1.754 to -1.772 Volt) and corrosion current (Icorr = 2.790 to 11.690μA/cm²), and lower polarization resistance (Rp = 425.170 to 1024.700 Ω) than non-anodized magnesium (Ecorr = -1.649 Volt; Icorr = 10.984 μA/cm²; Rp = 895.510 Ω). Anodized magnesium at the potential from 3.0 until 6.0 Volt indicates the presence of oxidation on the surface which leads to the less good characteristic pattern of dynamic potential.

Hydrogenated FAME (H-FAME) synthesis of Kemiri Sunan (Reutealis Trisperma (Blanco) Airy Shaw) using Nickel/Carbon catalyst is one of the methods to improve the oxidation stability of Kemiri Sunan biodiesel. The partial hydrogenation reaction breaks the unsaturated bond on FAME (Fatty Acid Methyl Ester), which is a key component of the determination of oxidative properties. Changes in FAME composition by partial hydrogenation reaction are predicted to change the oxidation stability, so it does not cause deposits that can damage the diesel engine injection system, pump system, and storage tank. Partial hydrogenation reaction is under conditions of 120 °C and 6 bars with 100:1, 100:5, 100:10 % wt catalyst in the stirred semi-batch autoclave reactor. H-FAME synthesis with 100:5 % wt Ni/C catalyst can decrease the iodine number which is the empirical measure of the number of unsaturated bonds from 166.77 to 155.64 (g-I₂/100 g) with an increase of oxidation stability from 650 to 665 minutes.

The development of renewable feedstock-based diesel fuel is start to come up as the solution of national energy problem. However, the thermal and oxidative stability of biodiesel is not good enough. As a result, biodiesel can only be added to commercial diesel fuel as a mixture with concentration under 20%. To get better thermal and oxidation stability, partial hydrogenation process is applied to biodiesel caused the increase of monounsaturated FAME structure. Activated carbon supported NiMo nanocrystal catalyst was used in partial hydrogenation reaction to get high activity, conversion, and selectivity. In this research, NiMo/C catalyst was prepared by modified microwave polyol process method, which is provided a rapid heating and cooling process. This method can produce nano-sized NiMo/C catalyst with short time and low energy consumption. NiMo/C catalyst produced in this research has 285.85 m²/gram surface area and 77.79 nm crystal size, resulting 20.41% conversion and 8.87% selectivity of biodiesel product. Further research should be conducted to obtain optimum condition.

Utilization of renewable energy in Indonesia is still relatively low compared to the non-renewable energy source of petroleum, coal, and natural gas. The limited amount of the non-renewable energy encourages the development of alternative fuels. Currently, low-grade bioethanol is one of the alternative fuel being developed. Bioethanol has a higher octane number compared to gasoline. Mixing of bioethanol requires a certain comparison, the mixing is intended to increase the octane number of a fuel mixture. The use of low-grade bioethanol (C2H5OH) as a substitute or mixture of fuels has an impact on engine performance. To get a more optimal effect on the fuel mixture, oxygenated cycloheptanol as an additive can be added to the fuel. This study examined the effect of fuel mixture with the addition of oxygenated cycloheptanol to single cylinder SI engine, 150 cc premix type at 100% throttle position. The tests was carried out on E5, E10, E15 and the addition of 0.5% oxygenated cycloheptanol at each fuel mixture with engine speed variation above 4000 rpm. Performance test will be performed with connecting the machine to a dynamometer. This study aims to obtain efficient performance on the engine with the addition of additives, there is an average increase of 9% in horsepower and 6% in torque.

The use of alternative energy source is expected to reduce fossil energy consumption and exhaust emissions. One of the non-fossil energy alternatives introduced for vehicles is bioethanol, it can produce in a simple way and cheap. Low-grade bioethanol has characteristics that depend on exhaust emissions generated. Low-grade bioethanol can be used as a substitute or mixture of fuel. The mixture of bioethanol and gasoline gives an effect to the increase of octane number and reduces the emission of CO2 produces. To get a more optimum effect on fuel consumption and emission, the oxygenated additive can be added to the fuel mixture. In this study, the effect of fuel consumption and emission was carried out by comparison of E5, E10, E15 without additive and with additive oxygenated cycloheptanol. The test will be performed by the method of calculating the amount of fuel consumption against the time to get specific fuel consumption. Emission test will be performed in single cylinder spark-ignition (SI) engine 150cc premix fuel with 100% opening throttle position connected to the gas analyzer in variation speed engine to see the emission gas. This study aims to obtain reduce the emission gas (CO2 and CO) and fuel consumption with the addition of the oxygenated additive.

Cellulose Nanocrystals (CNCs) have attracted a lot of attention as one of the promising green nanomaterials because of their interesting properties such as low density, high mechanical properties, high surface area, high biocompatibility and low toxicity. However, sulphuric acids is generally used in conventional method to prepare CNCs which is highly corrosive and harmful to environment. Replacing sulphuric acid with Ammonium Persulfate (APS), which possess lower toxicity, are desirable from environment point of view. In this research, preparation of CNCs from Oil Palm Empty Fruit Bunches (OPEFB) as alternative raw materials and using APS is reported. Three kinds of method were carried out before applying APS solution: (i) without pre-treatment, (ii) with alkali pre-treatment and (iii) with alkali-chloride pre-treatment. White-colored sample with crystallinity reaching 78% (XRD result) and particle size ranging between 31-113 nm (DLS result) was obtained. Those results implied that there were potential existence of CNCs in the samples.

The inhibitory effects of Curcuma xanthorrhiza extract on the corrosion of API 5L X42 steel in 1M HCl solution was investigated by using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy methods. In this study the concentration of C. xanthorrhiza extract used was 100, 250, 500, and 1000 ppm. The results show that C. xanthorrhiza inhibit the steel corrosion and acted as mixed type inhibitors. The corrosion rate decreased with the increasing of inhibitors concentrations. At the same time, inhibition efficiency increased with the increase of inhibitors concentrations. The adsorption of the extract on the steel surface was found to obey Langmuir's adsorption isotherm. The free energy value (ΔG_ads) indicated that the adsorption of the inhibitor molecules was typical of physisorption. It can be concluded that C. xanthorrhiza extract could be used as an alternative and environmental friendly inhibitor for API 5L X42 steel in acidic environment.

This study aimed to investigate the ability of Eleutherine americanna Merr. extract as an environment friendly inhibitor for API 5L X42 in 1M HCl. Corrosion inhibition ability of this extract was tested using tafel polarization, weight loss and electrochemical impedance spectroscopy methods. FTIR test was used to investigate flavonoid and antioxidant compound that play an important role to inhibit the corrosion process. In this study, the concentration of Eleutherine americanna Merr. extract used was 0 ppm, 100 ppm, 250 ppm, 500 ppm, and 1000 ppm. The corrosion rate decreases within the increasing of inhibitor's concentration. The highest percentage inhibition efficiency was found to be 84.5% at 1000 ppm. It can be concluded that Eleutherine americanna Mer. extract can be used as an alternative and environmental friendly inhibitor for API 5L X42 in 1M HCl.

This research objective was to investigate secang heartwood extract (caesalpinia sappan l) as a corrosion inhibitor on carbon steel metal (API 5L Gr B) in 3.5% NaCl environment. This research utilized polarization linier for the measurement method. Secang extract was adequate to reduce corrosion rate by 53.18% efficiency (based on polarization measurement). The most effective concentration of inhibitor secang was 2.0 ml/400 ml 3.5% NaCl. Furthermore, inhibitor efficiency of secang has tended to decrease by increasing of temperature. From polarization study, secang was indicated as mixed type inhibitor, with predominant cathodic effectiveness. In addition, the inhibition mechanism of secang was shown as physicsorption mechanism and obeys Langmuir Isotherm model.

Empty fruit bunch (EFB) of palm oil, an abundant agro-waste in Indonesia, was used as raw material of Cellulose Nanocrystals (CNCs) preparation. Instead of conventional acid mineral, phosphotungstic acid (H₃PW₁₂O₄₀, HPW) was used to hydrolyze cellulose due to recycling ability and easy handling. Before hydrolysis process, dried EFB was treated by 3% NaOH solution at 90°C for 2 hours and then bleached using 2% NaClO₂ solution at 80°C for 3 hours to remove hemicellulose and lignin. Hydrolysis reaction parameters such as temperature, acid concentration, and reaction time were optimized with fixed solid-liquid ratio of 1:40. Response surface method was used for experimental design to determine the optimum condition of each parameter by using software Minitab. In this study, pulp from dried EFB produced 44.8% yield of CNCs. Dynamic Light Scattering (DLS) analysis showed that most of CNCs equivalent diameter was 140 nm. Crystallinity index was observed at 73.3% using X-ray Diffraction (XRD) analysis. Thus, a green established process for the preparation of CNCs was achieved.

This study proposes the use of two-stage heat pump systems (SAHPs) for high temperature applications, 105°C. This system integrates solar thermal collectors and heat pumps into a hybrid system to meet the 400 kW heating load. The aim of this research is providing a method to deliver heat with sustainable energy resource, than to improve the performance of the system which is indicated by low exergy destruction. The model creation, performance evaluation and the optimization of solar assisted heat pump system are discussed in this paper. This system used R1234ze (E) as working fluid. A genetic algorithm is employed to optimize operation condition of the system. To ensure that the optimal solution obtained from the proposed method is an optimum condition, three constraints are selected, including evaporation temperatures, condensing temperatures and compressor temperatures while exergy destruction and total cost as the objective functions. The result showed that the system has an optimum condition at evaporating temperature of 317 K, Flash Tank temperature of 353.6 K and condensing temperature of 380.4 K with exergy destruction of 70.21 kW and total cost of 63,441 US$.

Biodiesel production is made by using edible or vegetable oils; however, their high prices and use as food resource are great limiting factors to their application. During the refining of palm oil, a lower-value by-product known as palm fatty acid distillate (PFAD) is generated in the fatty acid stripping and deodorization stages. PFAD is potentially a valuable, low-cost feedstock for the production of biodiesel. In this work, the esterification reactions of free fatty acid (FFA) in PFAD over sugarcane bagasse catalysts were studied. The effects of catalyst concentration (1 to 10 wt%), reaction temperature (30 to 60°C), and molar ratio of oil/methanol (1:6 to 1:12) on the conversion of FFA was studied to optimize the conditions for maximum conversion of FFA in PFAD and to observe the appropriate kinetic model for the experimental data. A kinetic model was developed on the basis of the Eley-Rideal mechanism according to the experimental data. The esterification reaction occurred between methanol adsorbed on solid base active sites and FFA from the liquid phase. The surface reaction of FFA with adsorbed methanol was assumed to be rate-determining. The collision factor value and activation energy for P-H model were found to be 1217.7985 L/mol.min and 24.2950 kJ/mol, then for E-R model were 1492.6375 L/mol.min and 19.5391 kJ/mol for E-R model, respectively.

Mining industry is one of the most important industries for the improvement in people's value in daily lives. Indonesia has abundant mineral resources. Nevertheless, these minerals are still in the depths of the earth and need to be explored so that the minerals are on the surface of the earth. In addition, it is necessary to also extraction process to be more efficient in the next process. Therefore, the method of mineral extraction needs to be further developed to obtain optimal results with the best use of energy but at the most competitive cost. In this study, the objective is to know the effect of reduction temperature on the increase of nickel contents in nickel laterite process using a pyrometallurgy extraction which will be performed in the varying temperature of 700°C, 800°C, 900°C, and 1000°C. The mixture contains coal reducer which will reduce iron metal and supposedly increase the nickel contents in nickel laterite ore. Moreover, Na₂SO₄ will be added as a constant variable where the sulfur in Na₂SO₄ is known to help extracting the nickel laterite. The tests include XRD, AAS, and proximate and ultimate test from coal. The result of this study shows that 700°C is the optimum temperature in doing the nickel laterite reduction. Apart from some factors that affect the final result, it is only at the temperature of 700°C that the nickel contents facing an increase from 1.16% to 1.18% after being reduced in a muffle furnace for an hour.

With the increasing demands of nickel in the world and the decreasing of nickel sulfide deposits, the processing of nickel laterite is the new challenge with selective reduction by using coal as reducing agent and Na2SO4 additives. This research aims to determine the preparation parameters of the pelletizing method before the reduction process in order to increase the content of the nickel in the reduction product. The samples were prepared by mixing limonite ore, coal, bentonite, and Na2SO4 additives, then continued by making the pellets with the variability of mass measurements of 5 grams, 10 grams and 15 grams. After the selective reduction, they were characterized by XRD to determine the formed phase, and an AAS test to determine the content after selective reduction. The test result of XRD showed the forming of magnetite, which were found in the pellets with mass size 5 grams. After all, fayalite phase was found in each size of pellet samples. The largest iron and nickel content was shown in the 5 gram pellets, 25% and 0.85%, respectively

In terms of its process, although only about 40% of the world's nickel reserves are classified as lateritic ore, nickel sulfide still dominates nickel laterite for its practicality. Because of the high demands on nickel, development and research on nickel mineral processing are needed to ensure that the demands are fulfilled from year to year. On this research, a study will be conducted on the effect of adding Na₂SO₄ to increase the level of nickel content in limonite by selective reduction process. The reduction process is done by heating limonite ore and coal as reducer from room temperature to 1000°C with temperature rising to 10°C/minute in mini furnace on varying addition of 0%, 5%, 10%, and 15% Na₂SO₄. After that, the reduction result is tested on XRD and AAS. It has been found that the nickel content has decreased, which is likely due to the excessive reduction time resulting in the magnetite being re-oxidized to hematite. Therefore, based on recovery calculations, the optimal addition of Na₂SO₄ is 5% by weight where the obtaining nickel content is 1.09%.

Issue of energy is important because energy is one of economic foundation to support a nation. Indonesia have abundant resources of renewable energy and it can be used as friendly energy source. Innovations continue to be developed to find the right method about good quality and cheap of energy sources that is widely available in nature. Calcium carbonate powder of shellfish are the one of the environmentally friendly materials that are available in nature. In this study, calcium carbonate are used in aqueous solution of water-ethylene glycol fluid with a ratio of 40:60. The purpose of this study is to determine characteristics and hydrodynamic behavior of non-Newtonian calcium carbonate solution that is flowed in a small pipe. Concentration of powder was from varied 100 ppm, 300 ppm and 500 ppm on the base fluid, respectively. The test was performed on a circular pipe with 4 mm of inner diameter, horizontally. Pressure drop was determined between two different points in which there were high pressure and low pressure taps by different data acquisition. Changes of friction factor value become a parameter of the indicator to drag reduction. The highest drag reduction in transition flow is about 26.3 % for the 300 ppm concentration with Reynolds number is around 3000.

Anaerobic digestion (AD) which treat food waste is a waste-to-energy method that produces liquid effluent. This by-product, known as digestate, contains high nutrients that could be recovered using ornamental aquatic macrophytes in a constructed wetland system. This study investigates the capacity of nutrient recovery of Canna indica, Iris pseudacarus, and Typha latifolia from liquid digestate, together improving the quality of AD effluent. Constructed wetland with T. latifolia effectively removed TSS and COD to meet the wastewater quality standards (TSS = 71 mg/L, COD = 56.735 mg/L). C. indica removed up to 72% N as the highest N removal efficiency, and recovered most of N, even though it still needs longer detention time to meet the standard. I. pseudacarus removed up to 98% P yet the average TP level in the plant was slightly above T. latifolia. The result shows that nutrient recovery using constructed wetland improves the effluent quality within short operation period, meanwhile C. indica and I. pseudacarus as ornamental aquatic macrophytes also added the aesthetic value to the environment.

The existence of fishery waste problem shows that the innovation of fishery processing not yet maximized in Indonesia. Both waste and fresh cuts of fish can be utilized by restructuring with transglutaminase enzyme addition as a crosslinking agent. This microbial transglutaminase (MTG) enzyme can alter protein functionalities by forming stable covalent bonds between residues of the amino acid of protein. Accordingly, this study focused on Snakehead Fish (Channa striata) is used as the protein source and variations of treatment conditions include incubation duration (2 days and 7 days) and the composition of enzyme and processed fish meat (0.0%, 0.5%, 1.0%) and. The results of this study showed the strong performance of crosslinking by MTG on processed fish meat. This is confirmed by an increase in texture profile parameters (hardness, cohesiveness, and elasticity), the detection of myosin changes, also wave number increment of C-N and an increase of intensity of C=O bonds. The highest effectivity value in the sample was achieved by variation of incubation duration of 7 days and the addition of 1.0% MTG enzyme with a value of 129,78% in hardness parameter in sample.

In this paper, we report the enhancement of the dielectric constant of barium titanate (BTO) through partial substitution of strontium to barium and crystallite size reduction through a high power ultrasonic treatment. The sample under investigation is Ba_1-xSr_xTiO₃ or BST with x = 0 and 0.3 compositions prepared through mechanical alloying of SrCO₃, BaCO₃ and TiO₂ precursors as the feedstock. All mechanically alloyed samples were crystalline powders with a single phase as confirmed by an x-ray diffractometer (XRD). The mechanically alloyed materials were consisted of multi-crystallite particles as confirmed both by XRD data analysis and particle size evaluation. Subject to an additional ultrasonic treatment, the multi-crystallite particles were fragmented toward mono-crystallite particles with the mean crystallite size about 52 nm after 12 hours irradiation. Even a smaller mean crystallite size (18 nm) with a narrower crystallites distribution then that of BTO was obtained in Ba_1-xSr_xTiO₃ with x = 0.3. Such a narrow crystallite size distribution with a small mean crystallite size has superior dielectric constant over those of BTO and doped BTO with a large mean crystallite size. The highest dielectric constant of 3000 was obtained at a frequency of 273 Hz in doped BTO after 12 hours ultrasonic irradiation. The value is 12 times higher than those of BTO and doped BTO with a large crystallite size.

Curcumin has known to have a long intense wavelength absorption in the visible region ranging from 420-580 nm. Because of that, curcumin is a promising material for use in dye sensitized solar cells. In this work, curcumin was extracted from turmeric (Curcuma longa L.) through a simple extraction technique using different organic solvents, i.e. acetone, methanol, and ethanol. The results from the extraction were applied as a sensitizer in dye sensitized solar cell applications. Suitable solvent for extraction that could give high efficiency in DSSC device were analysed. Characterization of the dye was performed using Fourier transform infrared (FTIR) and ultra violet-visible (UV-Vis), while the performance of DSSC was analysed through a simple current and potential different (I-V) curve analyser. The infrared results showed that all of the turmeric extracted dyes have the same tendency with the characteristic of curcumin. UV-Vis absorbance characteristics of the curcumin natural dye extracted using acetone, ethanol and methanol has the same tendency with plateau-like absorbance peak at around 490, 492, and 505 nm, respectively. The maximum power conversion efficiency (PCE) is found to be 7.88% obtained from the solvent of ethanol whereas the PCE obtained from other natural dyes extracted using acetone and methanol are found to be low, 2.23% and 1.25%, respectively. This finding is convincing in terms of efficiency in which the value from the dye extracted using ethanol has higher efficiency than that of the commercial organic dye RK1 with a PCE of 4.02%.

Oscillating Heat Pipe (OHP) is a passive heat exchanger operating on two phase flow principle. As one of the newest members of the heat pipe family, OHP has a complicated operating mechanism of working fluid flow. OHP is a potential device, which can be used for saving energy and cost. Although, OHP is a promising two-phase heat transfer device with excellent performance, simple structure and low cost but its operational characteristic is still not clear yet and debatable. As one of the non-destructive test, neutron radiography uses neutron beam techniques to penetrate heavy materials while beam are absorbed by lighter materials. This method is very suitable for use in visualization technique of the two-phase flow of heat transfer device with hydrogen-based fluids. In this paper, the visualization method is coupled with thermocouple temperature measurement. Aluminium OHP with 12 turns has been manufactured and tested. The dimension of aluminium OHP is made fit with the neutron beam size. DI Water with filing ratio 35 % has been chosen as the working fluid for the close loop OHP. Three level of heating power was applied to the evaporator section of OHP. The result showed that this preliminary study could reveal the temperature fluctuation of the thermocouple data. The condensation and evaporation also can be observed adequately with this method.

Indonesia and several tropical countries produce a lot of energy sources including palm oil, coconut, nyamplung, rubber seeds, kosambi and various other plants. The source can be converted into biodiesel or bioethanol. This is reinforced by Regulation of The Minister of Energy and Mineral Resources, the government issued Indonesia's National Energy Policy under Regulation of The Minister of Energy and Mineral Resources of The R.I. No. 12/2015. This regulation formalized the promotion of biofuels in Indonesia, for both ethanol and biodiesel, and established a 30% biofuel in national energy consumption mandate by 2025. However, consideration of the use of biodiesel fuel is the formation of deposits in the engine or combustion chamber. In this study, the formation of a deposit of biodiesel fuel was carried out by comparison of biodiesel B100-NA without additive with biodiesel variation plus antioxidant additives such as B100 + BHT, and B100 + PG performed by the method of fuel droplet to heat plate to know the characteristics and mechanism of deposit formation On each fuel variation. The research was conducted by the deposition process and evaporation of Diesel fuel which was repeatedly carried out on a hot plate. The plate is heated with temperature variations in the enclosed space so that the conditions are close to the real condition of the engine. This test uses hot room temperature test rig. Use of antioxidant additives to inhibit oxidation in biodiesel is expected to keep the acid number low and increase oxidative stability, which will help prevent excessive deposits in the combustion chamber. This study aims to find the optimal temperature for the growth of the deposit can be controlled.

Bintaro fruit (Cerbera manghas) contains 36.945 of cellulose and 38% of lignin which is potential as a source of raw material for making bioethanol. The purpose of this research is to know the effectiveness of formula in producing bioethanol by the process of bintaro. The methods used in this research are pretreatment, delignification, hydrolysis, fermentation, and distillation. Pretreatment was performed by subcooling the substrate at 80°C followed by milling it up to 60 mesh. Delignification was performed by soaking the substrate in 100°C of 1N NaOH and 1 barr for 30 minutes. Hydrolysis was carried out with sulfuric acid catalyst (H2SO4) variations of 5.5%, 6.0%, and 6.5% at 120°C for 60 minutes. Fermentation with Zymomonas in variation of 1%, 3%, and 5% at room temperature for 3 days. The fermented filtrate was distilled at 73°C to obtain ethanol and tested the levels of ethanol with chromatography gas. The results showed that the highest levels of ethanol is 9.977% resulted from 6.5% of sulfuric acid hydrolysis and 5% of Zymomonas mobilis fermentation. The high levels of ethanol is supported by qualitative test result of the presence of reducing sugars with fehling yielding of 7002 ppm red brick tested quantitatively by nelson somogyi method. In conclusion, the level of bioethanol produced is directly proportional to the increased concentration of sulfuric acid and Zymomonas mobilis. The conclusion is levels of bioethanol produced is directly proportional to the increase in the concentration of sulfuric acid and Zymomonas mobilis is used.

Nowadays, many countries prefer to use renewable energy and increase the capacity of power generations. One method to increase the capacity power uses a hybrid system. The aim of this paper is to introduce a software for simulating a hybrid power generation included renewable energy, which combines solar and wind power generations. This software is named as SPEKTRA. In order to represent the actual system, there are some editable variables to show exchange of solar and wind power outputs. This simulation is used to increase the understanding of the power generation in the hybrid system for users and to estimate the spending cost of the power generation on hybrid system. The SPEKTRA is developed using Visual Basic. Functional and developed simulation is analysed using the black box method. the result show that the output graph is similar to the theoretical review.

This paper introduces a system which can monitor the environment of the garbage center in a city. Comparing with developed countries, they have technologies to process garbage, while those technologies are still difficult to be implemented in developing countries. In Indonesia, garbage are mostly placed in a wide-open area called landfill, where methane gas could be produced by a decomposition process. The gas has a characteristic that it can be burned easily. However, it is potentially to be used as an alternative energy for gas stoves. Considering this characteristic, the gas should be managed appropriately for both of distributing and monitoring gas leakage. Since the production of methane gas is plentiful enough, the gas can be distributed among the households surrounding the garbage center. Monitoring of methane gas has to be done continuously and real time during producing and distributing, without generating pollutions to the environment. Here, the monitoring system has been developed using a micro controller equipped with a methane gas sensor, i.e., TGS 2611. The data of monitoring will be distributed using an Internet-based system, where a Wi-Fi module is attached to the micro controller to send and communicate with the web-based server. Furthermore, information of monitoring the gas can be accessed by using android application. The advantage of the proposed system is that the user can monitor, record, and get the information of gas level. The system can also be used as an early-warning system when the gas exceeds the limit and when a danger situation occurs. The proposed system was tested using the black box method to evaluate the functionality. Finally, the system is used to optimize the Waste Management program through the utilization of methane gas. Hence, the utilization of methane gas monitoring system is tested to the user, whether they can use it easily.

A renewable energy is a new topic in education in Indonesia, especially for vocational education. The problem is the teaching trainer as a learning media is still not available at Universitas Negeri Malang while developing a trainer is expensive. This paper introduces a renewable-energy simulator, which can show the process of converting energy using hybrid solar cell and wind power systems. In case of the solar cell system, the simulator shows the process of converting the sunlight beam to energy production. Furthermore, the simulator shows the watt peak (WP) of the daily solar beam. In the case of the wind-power system, the simulator shows the capacity of power generator considering the size of rotor, wind speed, and the type of generator. The unique point of this simulator is that the hybrid systems of solar cell and wind power systems are demonstrated. While solar cell can't be effective if the sunlight beam is not available, it can be supported by the wind-power system, which is available for 24 hours, but it is depending on the speed of wind. Thus, implementation of this simulator can help students easier to understand and optimise the development of power generation using renewable energy.

The tropical region has a richness of solar radiation with its consequences on building thermal comfort. For that exception, the photovoltaic hold a role in generating eco-friendly energy also. Two-dimensional geographical location, recognized as X-Y for translating latitude (X) and altitude (Y) are analyzed for determining the optimum integrated thermal comfort of building and energy generating. This research utilizes open space, courtyard, which not only provides a slimming body of the tropical building to reduce deepness of cross ventilation work but also develops potential green energy by a simultaneous method in making opening area. All were done by Ansys Fluent and Ecotect simulation method in order to give a recommendation for each location. The result highlighted that higher width and length different ratio for East-West orientation courtyard, more energy can be generated. It has a capability in reducing more than 10% of energy consumption with maintaining indoor temperature by providing air. Comparing latitude (X), altitude location (Y) shows the higher effect on providing thermal comfort and energy efficiency because the different tropical location has less difference on solar distribution.

Home energy management system (HEMS) concept rises from the development of smart homes that build interaction between users with their home appliances in order to operate automatically, multi-functionally, adaptably and efficiently. In line with technological developments and published regulations related to environmental issues, smart home applications evolve into HEMS applications which are not only to provide ease and convenience, but also to monitor and to make efficient energy use at home, thereby reducing peak power quantity and electricity bill. Smart grid is an intelligent power grid starting from its generation, transmission and distribution. It combines computing technology, artificial intelligence and communications technology which creates a smarter power system and is able to produce better power quality and lower generation cost. In the smart grid scheme, by means of HEMS applications, consumers can participate in improving the quality of power systems. This study will discuss about the development of HEMS in associated with smart grid technology particularly the role of HEMS application with its DSM (Demand Side Managment) and PEV (Plug-in Electric Vehicles) programs in the smart grid scheme to improve quality of power systems. Several studies have shown that the contribution of HEMS to the smart grid system can improve the power losses and voltage profile.

Pineapple Leaf Fibers (PALF) which is rich in cellulose, relatively inexpensive and abundantly available has the potential for polymer reinforcement. In this study, Polyethylene Terephthalatate (PET) was added with PALF and electro-spinned. The resulting mats were compared with PET neat electrospun. The samples later were examined by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) and contact angle (CA). Briefly, SEM results indicated that the present of fibers led to a tendency of lower average fiber diameter compared to the PET neat. Two distinct fiber networks with intersecting fibers were observed in PALF/PET. One networks probably corresponds to PET and the others to PALF. FTIR analysis shows the intensity peak represent carbonyl at ∼3400cm^-1 and ester at ∼1100 cm^-1 decreased. It is suggested interaction occurred between lone pair of oxygen in the group with hydrogen group in PALF. New peak were observed at 3400 cm^-1 in PALF/PET that indicated present of hydrogen bonding as well as its hydrophilic tendancy. The contact angle of PET signify high average value 156⁰ that comes with hydrophobic properties compared to PALF/PET with average value 16⁰ with more hydrophilic properties.

Indonesia is a country with the largest peatland in Southeast Asia. These vast peatland is spread throughout the country. In the last 2 decades, Indonesia encounter land fires and now becomes an annual land fire event. Later, observed that the land fire occurred because dry season in Indonesia causing the peat becomes dried enough to have hydrophobic characteristics and easily burned. This fire phenomena on peatland is determined by some factor such as, physical properties, organic content, oxygen concentration, etc. Peat has hydrophilic and hydrophobic properties as physical properties when treated differently. Initially raw peat has hydrophilic properties. However, in certain low level of moisture content, peat becomes hydrophobic. To examine this phenomenon, mechanical understanding based experiment was done. For hydrophilicity, the experiment will be using Shimadzu MOC63u Moisture Balance Analyzer. The peat sample which are used are Indonesian natural peat. The wet peat was dried by using moisture balance equipment with various time (0.5 till 6 hours with interval 0.5h) at 100°C. and loading peat into a tube with 2.15 cm in inner diameter and 5.5 cm long where both end are covered by wire mesh. Afterwards, the tube was being dipped into water in a certain depth. As for hydrophobicity, the experiment was done with the same method as hydrophilicity by using some of the dried peat. From the experiment, the mass loss, adsorption time, volume shrinkage and adsorption capacity and as well as hydrophobicity of peat will be shown in the result.

Dispersant is a chemical surfactant which can break down an oil from the water surface. Therefore, dispersant can be used to treating oil spills. The effectiveness of dispersant as oil emulsifier can be influenced by the temperature of the environment and concentration of oil and dispersant. This paper shows the influence of temperature variations, dispersant types and layers of sea water on oil spills by testing the light absorbance using spectrophotometer UV-Vis. The results of the experiments show that the biggest light absorbance occurs on the water surface at temperatures of 26° C C with area absorbing of 82.15 abs. Meanwhile, the smallest light absorbance is at temperatures of 16° C with wide absorbance 25.72 abs on the type of dispersant soluble. Wide light absorbance total greatest namely 26° C temperatures on the type of soluble with wide absorbance total 133.49 on three points of layers of water.

This paper presents studies on the influence of the nozzle tilt angle on the on the thermal radiation generated by diffusion jet flame. Analysis was limited to the nozzle tilt angle, distance and height of the heat flux measurement, and nozzle diameter. The studies were conducted for three different nozzle tilt angles of 0o, 45o and 90o, three different distances 10 cm, 15 cm and 20 cm, six different heights 10 cm, 20 cm, 30 cm, 40 cm, 50 cm and 60 cm, and two different nozzle diameters 17 mm and 11 mm. The thermal radiation intensity increased with the distance and height of measurements. The variation of horizontal and vertical jet flame was found to follow a linear equation. The studies also included investigation of flame shapes influence on the thermal radiation. The obtained results are presented in a graphical and tabular form. Based on the analysis of results the conclusion are established, important not only for the theoretical considerations but also in practice, especially in the context of immediate ignition on Liquefied Petroleum Gas as fuel for household leakage.

During the past 40 years, there have been 14 major accidents of oil spill in Indonesia, mostly as results of ship collisions. There are several methods in handling oil spill accident, in which the most effective methods are using mechanical oil skimmer with disc plate. The effectiveness of the oil skimmer on handling oil spills is influenced by various factors, such as the depth of the disk submerged or the disk surface area dipped into the oil spill, the area of the wiper sweep, the thickness of the oil on the disk surface, and the rotation speed of the disk. This paper presents the results of laboratory scale experiment of mechanical oil skimmer. The oil samples used are diesel engine oil with 15W-40 SAE and the water sample used is sea water. The experiment was conducted with variation of 27 mm and 55 mm of disc submersion depth or equal to dipped surface area of 31.35 cm² and 88,832 cm². The duration of the test for 3 data is 5 minutes. Based on theoretical calculations, the increase of rotation speed of the disk, the result of spill transport will also be higher. This is proved by the experimental results. The lifting process of oil spill is more effective with low rotation speed, because the result of oil spill transported will be more dominated by oil than water. In this test, the higher the rotation speed of the disk, the higher the water produced.

In this paper, the combination of double-flash and binary cycles for Ulubelu geothermal power plant is proposed and optimized by using the Matlab software. This proposed system uses real data and properties of brine exploited from the Ulubelu geothermal well in Indonesia and four working fluid candidates, namely n-Pentane, R141b, R123 and R245fa are used in binary cycles. Optimization using a multi-objective genetic algorithm with an exergoenomic approach is applied to find out the proposed system performance from both thermodynamic and economic point of view. In the optimization procedure, the exergy efficiency and total specific cost of output power become objective functions while the first flash pressure, second flash pressure and Organic Rankine Cycle (ORC) turbine inlet temperature are selected as constraints. The system performance proposed in this paper is compared with the performance of the existing system. The results show that n-pentane is the best working fluid where multi-objective optimization indicates that the system can generate 63.54 MW of power with thermal and exergy efficiencies of 17.59% and 65.26% and specific cost of 1.7049 USD / GJ at the selected optimal design point. Compared to the existing system, there is a significant improvement in performance both from thermodynamic performance and economic performance.

The objective of this paper is to predict hourly solar radiation in Faculty of Engineering, Universitas Indonesia, Depok, West Java, Indonesia (106.7942 longitude, -6.4025 latitude) as studied site. The calculation is based on several empirical models and compared to the measured data from BMKG. The comparison of theoretical data and measured data in order to know the influence of solar radiation parameters like solar irradiance condition, angstrom turbidity coefficient, and climate condition used to calculate the solar radiation at studied site. In order to evaluate the performance of solar radiation models, a statistical test was performed by using Mean Bias Error and Root Mean Square Error. The results indicate the best performance of solar radiation models that applicable in Indonesia. Therefore, Benjamin et al. model provides good performances for estimation of the hourly solar radiation.

Ignition delay time of liquefied petroleum for vehicle (LGV) fuel was predicted in this research. The method was using a detailed kinetic model of oxidation and combustion of propane/n-butane mixture. The validation of the model used experimental data in shock tubes in the temperature range from 1300 K to 1500 K and the pressure range from 2.5 bar to 10 bar for pure propane and pure n-butane. Calculated results of ignition delay time using the model have good agreement with experimental results indicating that the model may be used for LGV fuel. Simulation results of the model of LGV fuel show that the ignition delay time is faster when the n-butane fraction in the fuel is higher. The switchover of the ignition delay time order among different compositions of the fuels takes place at the initial temperature of 1200 K for the equivalence ratios of 1 and the initial pressure of 10 bar.

As in many other energy generating system, in the nuclear power plant, the use of natural circulation principle for the safety system is increasingly considered. The natural circulation could play an important role in providing emergency cooling of the nuclear reactor. The reliability of the use of natural circulation in the nuclear power plant should be demonstrated in order to assure the level of its safety. FASSIP-02 is a large scale test facility to study the natural circulation in the safety system of a nuclear power plant. To study the characteristics of the natural circulation and to help validating the design of FASSIP-02, a numerical study using RELAP5 code is undertaken. Based on the existing design of FASSIP-02, the numerical simulation is done with two variables, i.e. the heat flux and the pipe diameter. The effect of heat transfer surface area for dissipating the heat is also studied. The results show the natural circulation established in the FASSIP-02. The characteristics of the natural circulation with the values of several important parameters such as temperature, mass flow rate and pressure in the loop are obtained. The RELAP 5 calculations have provided the results that could be used to support the design and future operation of FASSIP-02.

In the future, the use of passive cooling system without electrical power input become highly considered to be implemented in the design of nuclear reactor safety system. Moreover, the lessons learned from the Fukushima-Daiichi accident encourage the incorporation of such passive cooling system. The passive safety cooling system is aimed to cope with both design bases as well as severe accidents. The natural circulation is one example parameter of the passive cooling system features being widely considered. However, some of the parameters involving in natural circulation are still being investigated, in particular the problem of flow instability. BATAN is designing a large-scale test loop facility, named FASSIP-02 loop, with a height of 11 meters between a heat source and a cooling source. The FASSIP-02 loop is designed to simulate the residual heat in the reference reactor. To ensure the validity of the design prior to the construction, it is necessary to make an analytical calculation using some correlations to estimate the natural circulation flow rate. The calculation method is performed by using the derived two principle correlations of the buoyancy force in the heating section and the gravitational force on the cooling section. The water temperatures in the heating section are varied at 50°C, 60°C, 70°C, 80°C and 90°C with the water temperature in the cooling tank pool are varied at 10°C, 20°C, 30°C, 40°C and 50°C. The calculation results can estimate the water temperature and volume are required. In addition, it could be used to determine the experimental matrix that is based on the FASSIP-02 loop design.

The disposal of Glass Fiber-Reinforced Plastic (GFRP) composites is becoming an environmental issue. To overcome the problem, biocomposites made of ramie fibers and tapioca starch might become an alternative to GFRP composites, due to their renewable properties, environmental friendly and easily degraded by nature. However, mechanical properties of fiber-reinforced starch based biocomposites are quite low due to high void content and poor fiber-matrix interface. In this research, the effect of the processing methods on tensile properties of tapioca starch - reinforced random ramie fiber biocomposites were studied. Ramie fiber reinforced tapioca starch biocomposites were fabricated by means of solution casting and compression molding technique. Random ramie fiber-reinforced tapioca starch biocomposites were succesfully made with the highest tensile strength and modulus elasticity of biocomposites were 18 MPa and 959 MPa respectively. The use of 1% NaOH alkalization process on ramie fiber increased tensile strength and modulus elasticity of biocomposites 64% and 54% respectively. Application of 120 °C compression temperature, increased tensile strength and modulus elasticity of biocomposites 18% and 74% respectively. Homogenous dispersion of ultimate fiber increased the tensile strength up to 91%. However, the addition of glycerol decreased the tensile strength and modulus elasticity for 46% and 39% respectively.

Magnesium (Mg) as one of the potential candidate material for absorbing hydrogen, because theoretically has the ability to absorb large quantities of hydrogen 7,6 wt%. However, the kinetic reaction of Mg is very slow. Its takes 60 minutes to adsorp hydrogen with the operating temperature (adsorb/desorb) high of 350°C. Therefore, in this study discusses the hydrogen storage materials based on MgH₂-SiO₂. The purpose of this study to improve desorption temperature of hydrogen storage system based on MgH₂. The main material is MgH₂ combined with inserting SiO₂ catalyst was successfully extracted from quartz sand with coprecipitation method. As for the material preparation process is done with the technique of mechanical alloying. Milling MgH₂+SiO₂ samples using a ball milling for 5 hours, with the ratio of ball to powder 10:1 and a speed of 400 rpm. By variation of the catalyst insertion of 1 wt%, 3 wt%, and 5 wt% of SiO₂. The results of XRD measurement known that the sample was reduced to scale nanocrystal. Phase arising from the result of XRD observation are MgH₂ phase as the main phase, and SiO₂ phase as a minor phase. DSC testing results show that the lowest desorption temperature obtained on the sample with the addition of inserts weight of the catalyst 5 wt% SiO₂ has milling for 5 hours which is equal 307,11°C.

Drag reduction on ship to decrease fuel consumption and achieve higher speeds has became the topic since the last decades. One of the most atractive idea is micro-bubble, in order to reduce frictional resistance. The purpose of this research is to identify micro-bubble drag reduction effect on Self Propelled Barge Model at 1:28 scale. The influences of air injection ratio and speed will also be investigated. Five injection ratio were used in this experiments; 0,2; 0,3; 0,4; 0,5; and 0,6. Experiments were done in the towing tank, member of ITTC. Micro-bubble was injected on bow and midship using two configurations; triangle stern and triangle bow. The results show that triangle stern is the best configuration with 5% - 40% drag reduction at 0,2; 0,3; and 0,4 injection ratio.

The total potential of wind energy in Indonesia reaches 144 GW. This wind energy potential is dominated by small wind speeds ranging from 4-6 m / s and about 113 GW. This is the reason why the development of small-scale wind powerplant is more feasible to be developed in Indonesia. The characteristics of local wind and geographical conditions of Indonesia which is an archipelagic country are fundamental in designing wind power and utilizing of local materials. This study aims to get local fast-growing wood of wind turbines blades in Indonesia, which has the best physical and mechanical properties of wood, and is tested computationally on certain airfoils and shows a uniform distribution of stress. The types of wood are tested in this study were Sengon (Albizia chinensis), Jabon (Antocephalus cadamba), and Balsa (Ochroma Rowlee grandiflorum). The test covers the basic properties of the wood, physical and mechanical properties. The test results showed that Jabon have density 0.34 was the best compared to Sengon (0.24) and balsa (0.18). The best dimensional stability (T/R Ratios) are Jabon (1.97), sengon (2.19) and balsa (2.84), respectively. With the highest density result and the lowest dimensional stability value, mechanical testing of Jabon wood shows the best mechanical properties. The simulation result using Q-Blade software was obtained airfoil NACA 4415 most suitable for local wind characteristics, and got the low value of stress and distribution color uniformly on each wood.

The building is one of construction sector that consumes high energy and contributes to the greenhouse gas (GHG) emission. Many researchers and academics attempt to reduce the negative impact of the building by introducing alternative technology through the internet of things (IoT) and building management system (BMS). The research aims to examine components related to the workspace of building and evaluate the cost and energy usage. The study combining quantitative and qualitative approaches through energy simulation, life-cycle cost approach, and in-depth interview. The results show three components from lighting, cooling, and office equipment that can be quantified. Every component consists of equipment to tailor the concept of a smart integrated workspace. The energy per square meter from proposed concept generates 48.36 kWh per square meter or lower than the current design. Overall it requires 203,586,240 rupiahs or 18% more efficient to the current layout.

Greenhouse gas and carbon emission have a considerable impact on the people behavior on constructing new buildings. One of the attempt to combat environmental issues is by implementing renewable energy such as photovoltaics (PV) into the buildings. However, a high cost from sustainability concept makes building owners or investors hesitate to use the device. The research aims to evaluate the solar energy implementation by taking university library building as the case study. Due to space and cost aspects, the analysis only considers lighting system. The life cycle cost is used to generate the best alternatives to the building. The results show three potential options; alternative one use public electricity from state-owned enterprises in the energy sector with a fluorescent lamp, alternative two use PV with a fluorescent lamp and alternative three use PV with LED lamp. Alternative three recommends as the most potential implementation on the building as it generates lower initial cost, moderate cost of operation and maintenance as well as fair salvage value.

Hydrogen storage in metal hydrides, compared to conventional methods, is regarded as one of the best solutions due to the higher volumetric storage capacity and safety. Magnesium and magnesium-based alloys are promising candidates for hydrogen storage. The hydrogen storage capacity of magnesium in the form of MgH₂ amounts to 7.6 wt%. Unfortunately, Mg has a high thermodynamic stability and therefore, relatively slow desorption kinetics, which are the major drawbacks for the application as a hydrogen storage material. Various techniques are developed to improve the sorption characteristics by accelerating the aforesaid processes. In this work we success to synthesis and investigate the catalytic effect of SiC and Ni (in nanostructure scale) on MgH₂ using reactive mechanical alloying method in 10 bar H₂. At first step, using SiC catalyst the sorption properties can be improved. The most promising step by using double catalysts of SiC and Ni (MgH₂-5wt%SiC-5wt%Ni) which absorp 5.7 wt% hydrogen and at the same time decrease the desorption temperature to 250°C. Compared to T onset of pure MgH₂ -which desorp at 380° C. To the best of our knowledge, this is the best result so far for MgH₂-SiC system.

Kalina cycle is a new concept in thermodynamics that convert heat energy into mechanical energy. The heat source in this system comes from the Lahendong geothermal source. The cycle is using a mixture of solution of two liquids with different boiling points for the working fluid. Water and ammonia are the most widely used combinations with a 30% - 70% ratio in this study. With the combined benefits of comparison ratios, the Kalina cycle is able to produce better exergy efficiency and exergoeconomoic compared to conventional Rankine cycle. Kalina cycle works on thermal efficiency around 40% - 60%. The objective of this study is to find optimization in exergy efficiency and exergoeconomoic based on Kalina cycle applied in Lahendong geothermal source used MATLAB-EES. The results showed that the optimal ammonia-water mixture occurred at 130.0626 °C, 2184.791 kPa, and 51.77% of basic solution can yield exergy value 2358.88517 W and use the cost 16994.9715 $/year.

Microbial Fuel Cell (MFC) is an energy conversion system used by bacteria to generate electricity from organic wastes. Currently, MFC electricity is still small, so it complemented by electrolytes. Previous research shows the addition of potassium persulfate can increase electric voltage 10-fold, but this is less economical so it is necessary to find alternative electrolyte. Sodium percarbonate is a cheap electrolyte which has buffering ability. Therefore, a performance study of single-chamber-MFC using sodium percarbonate electrolyte and or without buffer was conducted by measuring electricity production and tempe wastewater treatment quality (BOD and COD). This result was compared with the results of MFC with potassium persulfate with and without a buffer in the same procedure. In MFC containing sodium percarbonate, charge reversal occurred, with average power 0.04 mW/m², only 1.25% average power of MFC containing potassium persulfate. These results increased by buffer addition. Other results show that MFC containing sodium percarbonate will degrade more than 40% COD, greater than MFC with potassium persulfate, but still not efficient because Coloumb Efficiency was only in the range of 10^-6 %. Nevertheless, this system can produce 63% BOD₅ reduction when a buffer was not added.

Lipase is known enzyme for its ability to hydrolyse triglycerides into free fatty acid. There are so much sources od lipase such as plants, microbes, and animal. But, lipase from plant seems interesting owing to its huge amount than microbes' lipase and less harm than animal's lipase. Many experts have proved that vegetable lipase is a potential biocatalyst so that lipase from sesame seed and sesame sprout was investigated in this research. Lipase which was obtained from each sources were then poured with 0.3 g PVA and 40% palm oil in demineral water. The lipase-palm oil solutions were then titrated with 0.05 M NaOH obtaining hydrolysis percentage. Based on the research, sesame seed supernatant produces 1.36 mmol FFA with 39% hydrolysis. Sesame sprout extract produces 1.37 mmol FFA with 39.14% hydrolysis. Those samples also contain lauric acid, miristic acid, palmitic acid, oleic acid and stearic acid which detected by GC instrument.

Human needs increasing over years, energy is needed to fulfill the daily life. In the other hands, source of energy such as coal is decrease and become less and less. There is a renewable energy that can made from wind source. Wind energy can be obtained by using some tools such as wind turbine. Wind turbine is a device that used to convert wind energy into electricity. Wind turbine has developed to many variation. One of variation that added to the wind turbine especially on their blades is splitted winglet. This additional variation is an adaptation from recent aircraft. The advantages of using this typical of winglets on aircraft is increasing the lift coefficient and decreasing drag coefficient. The function of splitted winglet on wind turbine blades is to minimize the backflow on the tip of blades. This research expectation is turbine will get better performance. Comparing the turbine with the blade without winglets, with winglets and with splitted winglets. Turbine with the blades without winglets gives best performance among all the turbine variations. The air flow hit the turbine at 6 m/s, the performance of turbine without winglets give Cp about 5,2E-1. With the same velocity of airflow, the turbine with winglets and splitted winglets give Cp about 4,7E-1 and 2,1E-1.

Biodiesel is a methyl ester transesterification process from the result of triglyceride with a methyl reagent source using a catalyst. One of novel reagent used is Dimethyl Carbonate (DMC) which can eliminate the formation of glycerol as the byproduct through the reaction resulting a compound of glycerol dicarbonate. The advantage of this compound has the same physical properties and to be a mixture in one phase liquid product with methyl ester. Lipase is a hydrolase enzyme that can catalyze the formation of fatty acid molecule from the triglyceride containing oil in the reaction of transesterification. The purpose of this research is to produce biodiesel product by observing the formation of one phase mixture of biodiesel product from the palm oilusing methanol and DMC as the reagent, KOH and lipase catalyst andthe variation of molar ratio of the oil. To obtain the best biodiesel quality examined by four characteristics: methyl ester (FAME) content, density, viscosity, and cloud point. The result of this research is that biodiesel can be produced by both reagent, and for biodiesel by DMC there was only one-phase biodiesel formed without impurities shown visually. For catalyst variation, the best biodiesel produced by methanol is biodiesel with KOH catalyst and has 98.2% ester content, 0.858 g/ml density, and 4.58 cSt viscosity. The best biodiesel produced by dimethyl carbonate is biodiesel with KOH catalyst and has 89.0% ester content, 0.883 g/ml density, and 4.91 cSt viscosity.

Lately, artificial surfactant is more often used than natural surfactant for petroleum industry. The main advantages of using natural surfactant is because the continuous availability. Single Cell Oil, which utillizes one-cell microorganism, can be a solution, such as Aspergillus oryzae, to produce AA, DHA & EPA. A. oryzae was cultivated on Potato Dextrose Agar (PDA), Czapek Dox Agar (CDA) and Malt Extract Agar (MEA), and then the incubation times are 2,4,5,6 and 7 days in optimal medium. Lipids were extracted using ethanol and n-hexane. The characterization of lipid was done by gas chromatography (GC) method. The most optimal medium is CDA with a lipid concetration of 0,18 g. The best incubation time on CDA medium was 5 days with 0,216 g lipid content containing 0,123 g unsaturated fatty acid, 0,0613 g PUFA and 0,0615 g MUFA. The unsaturated fatty acid composition produced on the 5th day was 29.2% oleate; 29.1% linoleate and ± 0.046% EPA.

Gasification is one of the technologies to process biomass as a renewable alternative energy source. Steam biomass gasification using various clays derived from Indonesia was carried out with laboratory scale fluidized bed reactor to evaluate the activities of clay as catalysts. At the same time to elucidated the relationship between material bed characteristics and gasification process activity. Tar capturing ability was compared for activated clay, silica sand and clay minerals derived from Indonesia by using a laboratory scale fluidized bed reactor. Even raw clay minerals were found to reduce heavy tar and water-soluble species emissions and increased carbonaceous materials deposited on the bed materials compared to activated clay. Activity of some Indonesian clay revealed high performance on the biomass gasification due to the amount of acid center.

Heat transfer always occurs in human life and can be perceived its benefits and losses. The heat transfer is divided into three according to transfers media, namely conduction, convection, and radiation. One example of cases where there are three processes of heat transfer is when there is a fire in a room. During a fire, the heat from the fire will travel into the surrounding environment and affect the objects around it with radiation, conduction, and convection. Heat that travels through radiation certainly does not require a medium of delivery because the heat is traveled in the form of electromagnetic waves and can travel to a very long distance. Distance, view factor, and placement of an object will affect the amount of radiation to be received from the heat of fire. Therefore, to examine the effect of distance, the viewing factor and the placement of objects against radiation, writer designs a multi-axis heat flux sensor. Instrument with multi-axis heat flux sensors or by the name of a Multi-Axis Radiometer will be designed which will then be tested to determine the results of the design. Instrument called Multi-Axis because the workbench of the instrument can be rotated 90°. Testing of the apparatus will include the heating temperature, the distance of the sensor to the heater, the sensor offset to the heater, the viewing angle of the sensor to the heater, and the orientation of the workbench. The results of testing distance and offset are validated by the theoretical calculations.

Li₄Ti₅O₁₂ or LTO is one of many compounds that could be used as anode component in lithium battery. The most interesting aspect of using LTO as an anode is its long cycle life which is affected by its zero strain property during insertion and extraction of lithium ions. Despite its advantages, LTO still has problem in its capacity value which is limited to 175 mAh/g. Researchers have tried many methods to increase the capacity of LTO, such as making a composite from LTO host. In this composite, nano sized Si is used as additional element because its high theoretical capacity could increase the overall capacity of the LTO composite. In this research, LTO was synthesized by hydrothermal-mechanochemical methods before we mix it with nano Si in slurry making process. The mass variation of nano Si was 1%, 5%, and 10% in wt. XRD and SEM were used for material characterization. For the battery performance testing we used EIS, CV, and CD. This research will explain the effect of Si on the LTO/Si composite performance. From the testing, it is known that the highest capacity was obtained from LTO/Si-10% sample with 216.15 mAh/g, and able to retain 42.76% of its capacity at higher C-rate (4C). The results show that LTO/Si-10% could be used as an alternative for anode component.

The purpose of this study is to provide an analysis of the comparison and impact of changes in the model of Gas Transportation Tariff calculations through Pipes on the transportation of natural gas for fuel power plants in the region X. Which initially used a single tariff distance system that provides gas prices that are still not economically attractive, will be replaced with a more efficient multi-tariff postage stamp system. With the change of tariff calculation method, it will get the lower gas price and will inevitably increase the commercial appeal to be able to replace HSD (High-Speed Diesel) Generator which is expensive and cause more pollution. Initially, the substitution program is still less attractive because gas prices are still inefficient because the use of tariff calculation method is less precise. New tariffs are modeled by modifying cash flow and some variables with scenarios dividing tariffs into groups and re-modeling the volume of gas flowing in the pipeline through simulations using software and calculations. With the sensitivity test will also be done to provide the best scenarios to the efficiency of gas price formation. If gas prices are more efficient than fuel, it will further increase the attractiveness to accelerate fuel substitution of fuel with cleaner gas fuel and support Government programs. A comparison of the carbon decline will also be made to prove the substitution of diesel with gas to have a positive impact on the environment to provide an analysis of environmental issues. Finally, we propose that the application of a multi-tariff system will provide the best scenario for enhancing the efficiency of natural gas prices in the substitution of power generation from diesel into previously less attractive gas to be more efficient and more environmentally friendly.

Utilization of geothermal energy for water-dominated reservoir usually involves a separation process that turns geothermal fluid mixtures into pure steam and brine water. This process also occurred on Ulubelu's geothermal power plant (GPP). As waste energy from the power generation process, the remaining heat energy in brine water is still high enough to run an absorption refrigeration system (ARS). This study proposed an integrated power generation and absorption system that operate side by side for a further cooling process. ARS will be employed to produce a lower temperature of cooling water from the GPP's cooling tower and then pass it to GPP's condenser. The lower temperature of cooling water will affect steam condensation process and the vacuum pressure of condenser, moreover, increase power production and exergy efficiency of Ulubelu's GPP. The improvement of exergy efficiency & production capacity will be observed along with the rise of the investment cost as form as the annual cost of the ARS. A Multi-objective optimization using genetic algorithm will be conducted to minimize exergy efficiency and the annual cost of ARS. The optimization will be conducted using MATLAB along with EES for work fluid properties database. The temperature of generator, absorber, condenser, and evaporator of ARS are used as decision variables. Finally, the effect of integrated system and optimum value for each decision variables are presented in this study.

The objective of this paper is to get the most suitable model of monthly global solar radiation estimation in Jakarta which performs better than the others model. In this study, measured data of solar radiation were utilized to be compared with the empirical models from the literature and a new based-temperature model, to estimate the monthly intensities of global solar radiation in Jakarta, Indonesia (Latittude: 6.13° S, Longitude: 106.8° E). Global solar radiations were measured for two complete years, and the estimation of monthly solar radiation were calulated by four empirical models and also one linear regression model. The accuracy of the models was then analyzed in terms of some statistical indicators such as Mean Bias Error (MBE) and Root Mean Square Error (RMSE). The statistical analysis of result revealed that the empirical models have not the same accuracy, and it is concluded that there are the models that can be preferred for the estimation of monthly global solar radiation in Jakarta, Indonesia. The obtained results indicate that Allen is performing better than the others by obtaining maximum MBE of 0.52 and maximum RMSE of 1.82. It also can be said that Allen is the most suitable model for estimating a monthly global solar radiation in Jakarta, Indonesia.

Hepatits B is a viral infection which attack the liver. One of the compound that can overcome and inhibits Hepatitis B is Andrographolide. The compound was derived from Sambiloto plants (Andrographis paniculate). Andrographolide compound works by inhibiting α-glucosidase which assists the secretion of Hepatitis B virus. The goal of this research is to make nanoencapsulation of sambiloto leaf extracts that was encapsulated in chitosan and STPP. The nanoencapsulation will increase the bioavailability of the body for the administered Andrographolide. The size of the resulting particle at a variation of centrifugal speed of 8.000 RPM with the concentration ratio of chitosan : STPP equals to 0.2%:0.1% (g/mL), was 68.3nm. The loading capacity of the nanoparticles is 67.20% and the encapsulation efficiency of the nanoparticles is 99.48%. The release profile has a cumulative release of 34.55% with slow release in gastric pH conditions and followed by a burst release in intestine pH conditions.

There are several substances that needs to be fulfill to keep the brain cell growth such as AA, DHA and EPA. Fungi is one of the alternative source of omega 3, omega 6, omega 9 especially AA, DHA and EPA. This research variates operating condition that is suitable for the growth of Aspergillus oryzae in AA, DHA, and EPA fatty acid production with Submerged Fermentation using synthetic medium. Aspergillus oryzae cultivated in medium using glucose as carbon source and Ammonium sulfate and yeast extract as nitrogen source. The extraction method using ethanol and n-hexane as solvent. The result shows that optimum agitation rate for unsaturated fatty acid production of Aspergillus oryzae is 120 RPM, lipid yield 28,28% and unsaturated fatty acid content 50,36 % and EPA content 2,42 %. Optimum medium pH for PUFA production of Aspergillus oryzae is 6, lipid yield 22,35 % and unsaturated fatty acid content 45,5 %. optimum incubation temperature for unsaturated fatty acid production of Aspergillus oryzae is 25 °C, lipid yield 13,19 % and unsaturated fatty acid content 62,15 %. Unsaturated fatty acids produced from Aspergillus oryzae are oleic, linoleic, linolenic and EPA.

Li₄Ti₅O₁₂ (lithium titanate) were synthesized by sol-gel and hydrothermal method with LiOH as lithium ion source. Li₄Ti₅O₁₂/Sn composites anode were preparared by ball mill method with three of Sn variation. X-ray diffraction shows spinel, TiO₂, and Sn phases with anatase and rutile residue. The lowest electrolyte resistance obtained at the highest Sn value. The specific capacity of battery can be increased from addition of Sn by up to 258.6 mAh/g. Alloying and dealloying reaction of Li_xSn accomodate the increased specific capacity from charge/discharge. However, Thevolume expansion from LixSn leads to loss of capacity when the C rate increases. The efficient capacity at low and high charge-discharge rate obtained at the highest value of added Sn.

Ferritic steel is a potential metal candidate for interconnect solid oxide fuel cell (SOFC) because its ability to form chromia layer at the surface during high temperature operation. However, chromia based oxide scales is reluctant to the evaporation of Cr from the oxide–gas interface. In this work, a combination of titanium alloying and application of Co₃O₄ spinel coating using dip coating method are carried out to improve the performance of ferritic steels as SOFC interconnect. The oxidation behavior of coated and uncoated Fe-20wt.%Cr alloys with different titanium contents: 0, 0.5, and 1 wt.% are studied as a function of time in air atmosphere. The samples were isothermally oxidized at 800°C for 24, 48, and 96 h in a box furnace. Preoxidation experiment were carried out on the alloys before the application of Co₃O₄ coating to improve its adherence. X-ray diffraction analysis (XRD) and Scanning Electron Microscope (SEM) were used for characterization of the prepared samples. The results shows that increasing the concentration of titanium in the alloys both for coated and uncoated samples caused the increased oxidation rates. The oxidation resistance of Co₃O₄ coated samples indicated from the weight change measurement was larger than that of the uncoated samples. Co₃O₄ coating is not effective for improving the oxidation resistance of samples.

Babassu endocarp were used to prepare activated carbons by physical activation via microwave radiation for the first time. The pyrolysis temperature was 600°C and the derived biochar were activated in CO₂atmosphereat 700, 750 and 800°C for 30 min. The material was characterized using scanning electron microscopy (SEM). The porous properties of the activated carbons obtained including the Brunauer-Emmett-Teller (BET) surface area, pore volume, and average pore diameter were determined by nitrogen adsorption isotherms at 77.32 K. The experimental results showed that most pores occurred during the activation predominantly as micropores. Endocarp babassu can be used as precursor to produce activated carbon with a rather well-developed porosity by pyrolysis and physical activation by two-steps with CO₂ activation via microwaves radiation. The activated carbon, with a low production cost, could be suitable for applications in gaseous pollutant adsorption, adsorb iodine, methylene blue, and residual chlorine.

Ecotect Software has been used to calculate building's energy consumption by simulating its context within the environment. Mostly use by architects and building engineers to enhance their design advancements, the software is embedded to the main Autodesk CAD architecture, fully compatible with Autodesk REVIT. Research Studies on many existing buildings have been performed to evaluate its building's performance. It is related to its environment, especially on dealing with solar heat, its nature for day-lighting, natural airflow for ventilation, and its energy consumption for man-made systems such as Air Conditioning and Lighting.

This research is conducted to reach basic optimum efficiency of an existing building at UI Campus in Depok. After using ecotect software we presumed that some strategic upgrading design propositions should be done to minimize the daily energy consumptions on air conditioning and lighting. Sensitive to the annual solar path and air/wind direction, we could propose an alternative to maximize the use of natural resource to reduce the building's energy consumption.

When being transported by pipeline, natural gas is often emitted to the atmosphere, either for depressurization (venting emissions) or leak through the pipeline (fugitive emission). The emission level must be well estimated to provide relevant informations and recommendation to formulate strategies for reducing greenhouse gas (GHG) emission. Organizations such as INGAA (The Interstate Natural Gas Association of America) and IPCC (Intergovernmental Panel on Climate Change) provide GHG estimation guidelines which are adopted by many companies and countries. This study estimates the emission level of a natural gas pipeline in West Java using emission factors referring to INGAA and IPCC guidelines with flow rate variation. The result shows that the flow rate variation affects the total emission based on Tier 2 and Tier 3 INGAA as well as Tier 1 IPCC. It is also shown that fugitive emissions dominate the total emission of gas pipeline. However, the use of different methodologies and guidelines gives different emission level for the same pipeline. Different estimation results of emission level have been reviewed and national emission factors database for gas transmission is highly suggested to be developed.

The power plant is one of the several industries whose product are used by consumers directly. The power plant requires an appropriate control strategy based on real-plant to maintain electricity production,. Turbine Follow Control (TFC) is one of the several control strategies for keeping electricity production. TFC is a control strategy that used to control throttle pressure based on Advanced Regulatory Control (ARC) concept. When there is a change of load on the generator, the error signal will be received by the indicator control. The error signal is used to respond fuel arrangement to maintain the main steam production. Furthermore, the changes of main steam production indicated by the pressure indicator control. It will be responded by the turbine governor valve to carry out a follow-up response in maintaining the main steam towards the turbine. The actual response is given in the form of the percentage of valve. This paper has been modeled TFC strategy using Internal Model Control (IMC) tuning method and First Order Plus Dead Time (FOPDT) approach for getting good control response based on HYSYS. In addition, IMC tuning response in this paper also depends on the ± 5% from setpoint test. From modeling of TFC based on HYSYS, the simulation shows that TFC is precise control strategy to handle the changes of load on the generator with integral absolute error value are 102,087.7 for +5% from setpoint test and 122,947.1 for -5% from setpoint test.

The demand of lithium-ion battery (LIB) has been increased for high power application in transportation system. Thus, the current use of graphite as anode material needs to be replaced, due to formation of unwanted solid-electrolyte interphase (SEI) layer consuming intercalated Li+ that reduces the LIB performance and may cause ignition of the battery in high load usage. One of the candidates for anode material to replace graphite is lithium titanate (LTO), since the LTO does not form SEI and exhibits high-power with outstanding safety properties. This LTO compound was synthesized by mixing the TiO₂ xerogel of anatase phase and lithium carbonate (Li2CO3) as a source of lithium-ion followed by sintering at temperatures of 750°C to obtain the LTO with spinel crystalline phase. However, the LTO has the low theoretical capacity, i.e: 175 mAh/g, with real specific capacity obtained is at 114 mAh/g. To increase the LTO specific capacity, the addition of 10, 20 and 30 wt.% silicon microparticle which has theoretical capacity of 4200 mAh/g was conducted during preparation of the slurry anode mixture to minimize the formation of SiO2. Anode sheet was made with Si/LTO and assembled into half-cell coin battery with lithium metal sheet as the counter electrode. Electro-impedance spectroscopy (EIS), Cyclic voltammetry (CV), and charge discharge (CD) testing were conducted to examine the battery performance. From EIS testing, the lowest impedance was obtained for the sample of 20 wt.% Si, while the highest impedance value obtained in 30 wt.% Si. The CV testing shows that the highest capacity at 141.1 mAh/g is achieved at the composition of 10 wt.% Si. Finally, from the CD testing, this Si/LTO anode could withstand the charge-discharge until 12 C and shows good stability until 100 cycles. From EIS and CV testing known that the optimum composition having the best performance is ranging from 10 wt.% to 20 wt.% Si. It is predicted that at higher composition, the pulverization of Si particle is occurred declining the performance of Si/LTO anode.

In our earlier works, the catalyst USY zeolite was tested for the pyrolysis of High density polyethylene (HDPE). It yielded 71% liquid oil that could be separated into diesel and gasoline-like fractions [3]. However, the high cost of this catalyst led to the present study where the effects of different low-cost catalysts on catalytic cracking of HDPE were investigated. GC-MS analysis were performed to check the carbon distribution of each sample and to make theoretical gasoline/diesel quantification in the pyrolysis liquids. Products where compared by studying carbon distribution, condensable range, branching degrees and reaction speeds. According to all those parameters, none of them outperformed USY zeolite. The Second Part has been conducted to observe the regeneration of USY Zeolite and monitor its performance for its economic value. The regeneration was done 10 times and the performance was monitored after every experiment with respect to % of heavier compound yields, carbon distribution range, char deposition range and gasoline and diesel yields. It was found that the regenerated catalyst loses its capability very slowly and even after 10 regenerations products characteristics were not sensibly altered.

NOx is produced from the reaction between nitrogen, oxygen and even hydrocarbons (during combustion), especially at high temperatures. Nitrogen oxide compounds are one of the harmful emissions that can result from fuel combustion. This research aims to find out the performance of super hydrophobic membrane contactors in the absorption process of N₂O from its mixture with air using acid solution and hydrogen peroxide. N₂O gas must be reduced from the exhaust gas especially to meet the regulations applicable to the environment due to the hazardous nature of the N2O gases. The experimental results showed that the amount of NOx absorbed and the absorption efficiency increased with increasing absorbent flow rate in the membrane contactor. Meanwhile, the concentration of NOX in the outlet gas decreased with increasing absorbent flow rate.

Human body has limited ability to synthesize unsaturated fatty acids such as AA, DHA, EPA. These fatty acids are essential for the body. This study initiated the efforts to produce unsaturated fatty acids of microorganisms, with low cost and high percentage. This study used tapioca and tofu waste as a medium for Aspergillus. In addition, this study analyzed the varying of carbon concentration to the maximum lipid production from Aspergillus oryzae and determine the optimum rate of agitation against lipid production from Aspergillus oryzae. The results shows that the optimum composition of AA, DHA, EPA are 0.18% (w / w), 0.33% (w / w), and 2.96% (w/w) respectively in concentration carbon of 9% (w/w) and agitation rate of 120 RPM.

The purpose of this study is to model the different tariffs on the transportation of natural gas through a pipeline for several shipper classes in an open access natural gas pipeline transmission line called a multi-tariff system. The determination of the natural gas tariff through the Open Access pipeline in Indonesia is mostly set using a distance system with the same value for all types of the shipper. The principle of justice is considered to be achieved from uniform tariffs for all the shipper, whereas in practice the separation of tariffs for each shipper group is currently essential. The proposed new tariff modeling is done by modifying the initial equations of the single-tariff model. Besides giving a new model proposal of tariff calculation for the multi-tariff system, in this research will also be modified free cash flow for new tariff calculation scheme and will be done the validity test on the formula. So that will get a multi-tariff calculation model which can become one of proposal material enter for Regulators to be able to set a fair tariff for the shipper without changing the economics of the transporter and can produce competitive gas prices to substitute clean energy sources for certain consumers such as electricity generation.

Bacterial lipase has been developed lately because of its advantage to produce with large scale. Culture of Bacillus subtilis was grown to produce lipase in Waste Cooking Oil (WCO) using submerged fermentation (SmF) method. The enzyme activity of the culture was improved by using different concentration of inoculum, substrate, nitrogen source, inducer, and Ca²⁺ ion at 30°C for 84h fermentation. Lipolytic activity of crude lipase was determined using titrimetric method with hydrolysis reaction. Maximum activity of lipase (4.96 U/mL) was found at 5% (v/v) inoculum, 4% (v/v) WCO, 0.5% (w/v) yeast extract, 0.25% (v/v) olive oil, and 10 mM Ca²⁺ that present in medium culture. Later, the crude lipase has been dried with spray dryer and resulting 17.33 gr of dry lipase powder per 500 mL crude lipase.

Indonesian government has a flagship program that is to promote the nation through the maritime sector and make Indonesia as Global Maritime Fulcrum. To achieve that, sea transportation is very important for the development of Indonesia. But sea transportation is also the highest contributor to the air pollution and global warming. In order to reduce the source of global warming Indonesian Government has a strategic plan to gradually replace the use of fossil energy with renewable energy. One of the renewable energy that can be used effectively in Indonesia is solar energy, because Indonesia located along the equator and has a high intensity of sunlight that means it has excellent solar energy availability. In attempt to contribute to the Government's energy strategic plan, the research is aimed to design a solar-powered electric boat with single pilot. The project is a further development of the solar boat created by the Universitas Indonesia team that participated in the International Solar-boat Challenge competition in the Netherlands. The paper is focused on the design and calculation of its mechanical system. The system is divided into propulsion system, steering system, and bilge pump system. The research is conducted based on literature study, discussion with experts, and surveys to the solar-powered electric boat had been designed previously for the race. Collected data are then used as input for the calculation and simulation of the vessel being designed. It is expected that the study could optimize the mechanical system of the solar-powered electric boat, and can be developed for recreational use in Indonesian waters.

Non-stoichiometry sulphur-containing precursors were studied to picture its connection to the formation of kesterite Cu₂ZnSnS₄ (CZTS) phase. The precursors were prepared from metal (Cu-Zn-Sn) chlorides with ethanol as solvent and 2-mercaptopropioninc acid as capping ligand. Mol ratio of S/Cu 4.4 was observed as the limit of non-stoichiometry. Confirmed by XRD characterization, the employment of sulphur in higher concentration resulted in the formation of secondary phases with a porous morphology. Further, a modification in holding time of annealing treatment was successfully improved the crystallinity of the CZTS film. The SEM micrograph was showed the formation of well-growth CZTS grains with size ∼ 1.5 μm. However, porosity was still encountered at the surface film as indication of insufficient growth processes (heat treatment). The energy band characteristic of the film is 1.4 eV, determined by extrapolating the gradient line of (αhυ)² vs hυ (photon energy). The route presented in this paper offers alternative solution to synthesize CZTS semiconductor from ethanol-based precursor.

Nowadays the great challenge to energy engineers is how to develop new and renewable energy sources to reduce the use of fossil fuels. In this direction, the research focuses on the recycle of wasted heat energy on a motorcycle exhaust gas into electrical energy using the concept of seed back. Recycle energy using this concept on a motorcycle is done because the bike has the energy efficiency of ± 35 – 40 % while the rest were dumped unceremoniously in the form of heat energy that is issued through the exhaust. This research aims to know the characteristics of the output voltage heat pipe sink thermoelectric generator utilizing waste heat of the motorcycle. This research has been done on the measurement of the output voltage is generated by the thermoelectric module series TECI-12706B type SP1848-27145 SA as a heat pipe sink thermoelectric generator to produce electrical energy. This research was conducted to know the output voltage from 4 thermoelectric modules arranged in series or parallel. furthermore this thermoelectric generator will be the main energy source for SSUPER-BT devices. Stages of the research done by performing laboratory and road testing. In laboratory testing, simulation of thermoelectric generator made using aluminium rods contain Heater. two sides of the aluminium coupled to thermoelectric modules, heat pipe and CPU fan. in each experiment, the thermoelectric modules strung together in series or in parallel. The results showed on the TEGs with 4 thermoelectric modules in series were able to produce higher output voltage and current compared to TEGs with 2 thermoelectric modules with output voltage reaching 15.7 volts and 7.7 volts respectively. The TEGs circuit with 4 thermoelectric modules produces 72.6% greater power than TEGs with 2 thermoelectric modules.