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Fuel requirement increased along with the increased of population also industrial progress, meanwhile the alternative fuel always decreasing. People also faced by the problem of increasing amount of waste, either its organic or anorganic. In this case mahogany waste and polypropylene plastic waste which still rarely used by people can be a solution to make an alternative fuel processed by pyrolysis process. This study is using experiment method with analysis descriptive quantitative technique. This study conducted with pyrolysis process to mixed biomass sawdust mahogany and polypropylene plastic waste with the 100%-0%,75%:25%, 50%:50%, 25%:25%, and 0%:100% ratio, next are do pyrolysis oil test which was quantity test. there is an influence of variety mixed biomass sawdust mahogany and polypropylene plastic waste ratio to quantity of pyrolysis oil. The most quantity is produced by mixed variety 100% of polypropylene plastic as much as 1026,67 ml with 391°C temperature on T1, 345°C on T2, 367,75°C on T3.

In this case, the recovery of excess heat in the steel-making process becomes challenging to save energy effectively and efficiently. One way to help the process of heat recovery in the steel-making process is with a heat exchanger. This heat exchanger maximizes the production process work. However, in the application, the heat exchanger developed to date can still work optimally. Based on the literature study that has been done previously for the design of the heat exchanger, in this study, the addition of four longitudinal fins variations with the cross-flow flow was carried out. This research compares the heat exchanger performance finned pipes with pipes without fins design, where liquid and airflow rates are varied. This study evaluated whether the longitudinal fins configuration and the fluid flow rate affect the cross-flow heat exchanger performance. The results show that fins addition on the copper pipes increases the value of Nusselt number 2.56% in liquid fluid and 16.57% in air fluid and increases the NTU value of its effectiveness by 24.77%.

UD. Sunarso Mebel is a business engaged in the furniture industry with management, including the design stage, material search, sawing, shrinking, sorting, and assembly for the final product of furniture. Production process for mortise and tenon joint on UD. Sunarso Mebel identified problems that could have been more productive. UD. Sunarso Mebel uses conventional tools that are ineffective, efficient, and interfere with worker comfort. Therefore, the fabrication of integrated tenon wood machines is needed, about actual needs and conditions. The stages of this program include the formulation of the design, the tools' manufacturing stage, and the implementation stage. Using this integrated tenon wood machine increases the cutting speed of one wood couple to 10 seconds from the conventional method of 300 seconds. The stage of cutting one break that is needed is only one stage compared to the conventional method, which is three stages. The manufacturing capacity of furniture products has become nine times faster. Thus, these integrated tenon wood machines can increase the productivity of furniture products on UD. Sunarso Mebel. The ergonomics of integrated tenon wood machines are classified as low risk, so it is ready and safe for use.

Vocational graduates' readiness for selecting careers is an important topic for vocational education research. Although there have been many studies on vocational student career selection readiness, there are only few studies on the roles of teaching quality, social capital, and psychological capital in shaping vocational students' readiness for selecting careers. This study aims to examine the antecedent factors of high school students' readiness for career selection which involve teaching quality, psychological capital, and social capital factors. This study employed the quantitative approach with ex-post facto design. The data were randomly collected from 279 vocational high school students in North Lampung-Indonesia by means of online questionnaires. SEM analysis was carried out in this study to see the effects among variables. The results show that readiness for selecting careers is influenced by teaching quality and psychological capital, as social capital does not directly influence student readiness. Besides, psychological capital is influenced by teaching quality and social capital. Then, social capital is influenced by teaching quality. Social and psychological capitals together mediate the effect of teaching quality on the readiness for selecting careers. The research findings present some implications for vocational education practitioners wishing to make further improvements.

This study aims to analyze the effect of variations in the number of blades and the use of end plates on the cut in speed of Helical Savonius wind turbine. The method used in this research is the experimental method. The variables used in this study are variations in wind speed from 1 to 5 m/s with intervals of 0.5 m/s. Variations in the number of blades are 2,3, and 4 blades. Variations in the use of end plates and without end plates. The results of this study was found that variations in the number of blades and the use of end plates affect the cut in speed of helical Savonius wind turbine. The fewer the number of turbine blades, the better the turbine's cut in speed will be. 2 blade’s Helical Savonius wind turbine with end plate is turbine variation that is able to produce best cut in speed of 1.97 m/s, compared to other variations.

The main purpose of this study was to determine the effect of variations in gamma ray dose on the physical and mechanical properties of natural fiber reinforced polymer blend composites. The method used in this research is experimental. This research was conducted on polymer blend composites, namely recycled High Density Polyethylene (rHDPE) and recycled Polypropylene (rPP) with bamboo fiber reinforcement with variations in gamma ray doses of 0 kGy, 25 kGy, 50 kGy, and 75 kGy. Bamboo is processed using a crusher into fibers with a size of 40 mesh and treated with 5% NaOH alkali for 10 minutes then dried using oven for 24 hour at a temperature of 105 °C to remove lignin contained in bamboo fibers. The composite was made using two machines, namely an extrusion machine with a heater temperature of 175 °C, 180 ºC, 185 ºC, and 190 ºC with a screw speed of 25 rpm. Then the injection molding machine with a temperature of 220 ºC with a specimen mold temperature of 90 ºC and an injection pressure of about 45 bar for 20 minutes. Gamma ray treatment was carried out after making the specimen before testing. Where a gamma cell irradiator is used and as a source of gamma rays, cobalt-60 (Co-60) is used. Tensile and water absorption tests are used to determine the physical and mechanical properties of the composite material according to ASTM D638 type V and ASTM D570-98 standards. The test results showed that the higher the dose used, the lower the physical and mechanical properties of the composite. The highest tensile strength was found at the 25 kGy dose treatment of 13.68 MPa and the lowest at the 75 kGy dose treatment. The lowest water content absorption and thickness expansion after 144 hours of immersion were at a 50 kGy gamma dose of 3.43% and 1.27%, respectively. Meanwhile, the highest condition was found at the 75 kGy gamma ray dose of 3.79% and 1.42%, respectively.

This study with stationary test aims to (1) To investigate the effect of using step up voltage on Honda Beat motorcycles on fuel consumption with stationary test. (2) To investigate the variation of the best voltage from the use of step up voltage on the fuel consumption of Honda Beat 2013 motorcycles with stationary test. (3) To investigate the effect of the use of a mixture of bioethanol and pertalite fuels on the fuel consumption of Honda Beat motorcycles with stationary test. (4) To investigate the variation of the best concentration of mixing bioethanol in pertalite on the fuel consumption of a Honda Beat 2013 motorcycle with stationary test. (5) To investigate the best configuration of a mixture of bioethanol and the use of step up voltage on the fuel consumption of a Honda Beat motorcycle with stationary test. Data collection techniques are needed to obtain results. valid data from the tests that have been carried out. Experimental techniques were used to collect data from each of the variables studied. So that the determination of variables is very necessary by carrying out clear research and testing procedures in order to facilitate the process of collecting data from the results of these experiments. The test results on the stationary test, namely the use of step up voltage, there is an effect on fuel consumption, the best is set at voltage of 14,3 V at 3.65 ml/min. The use of variations in the concentration of bioethanol in pertalite has an effect on fuel consumption with the best results using a 20% bioethanol concentration of 4.56 ml/minute. The best configuration was obtained when the step up voltage was set at 14.1 V and the 25% bioethanol concentration was 4.01 ml/min. more perfect due to a decrease in the level of fuel consumption in the tested vehicle.

The purpose of this study: (1) To investigate the effect of step up voltage on fuel consumption on Honda Beat motorcycles. (2) Investigating the effect of variations in the use of pertalite and pertamax fuels on the use of step up voltage on fuel consumption on Honda Beat motorcycles. (3) Investigating the best configuration on the use of Step Up Voltage on fuel consumption on a Honda Beat motorcycle. The research method used is descriptive investigation. The data obtained from the experimental results are entered into a table displayed in the form of a graph for later analysis. The descriptive research that will be used is a comparative study. The independent variables in this study: (1) The use of step up voltage (2) Variations in the use of pertalite and pertamax fuels (3) Variations in engine speed of 1500 rpm, 2000 rpm, and 2500 rpm. (4) Voltage variations are 13.7 V, 13.9 V, 14.1 V, 14.3 V, 14.5 V, and 14.7 V. The dependent variable in this study is fuel consumption under standard conditions and those who have used step-up voltage. The control variable used was a 2013 Honda Beat motorcycle and a 50 ml measuring cup. The results of this study: (1) The use of step up voltage affects the fuel consumption of Honda Beat motorcycles in 2013 because there is a difference in fuel consumption before using step up voltage and after using step up voltage. The use of this tool has been proven to be able to reduce fuel consumption by 0.87 ml/minute at 1500 rpm, with these results, the use of step up voltage affects the combustion quality of the fuel and air mixture in the combustion chamber of a motor vehicle which becomes more perfect due to a decrease the fuel consumption of the tested motor vehicle. (2) The use of Pertamax fuel can reduce fuel consumption. The average fuel consumption produced is 6.59 ml/minute, a decrease of 2.33 ml/minute from pertalite fuel. (3) The best configuration to obtain the lowest fuel consumption is to use a step up voltage with Pertamax fuel at a voltage of 14.3 V. This configuration is the best than the other configurations, with a fuel consumption of 3.76 ml/minute at 1500 rpm.

The purposes of this study are: (1) To determine the effect of using Step Up Voltage on torque and power of Honda Beat 2013 motorcycles. (2) To determine the effect of using Pertalie and Pertamax fuel variations on torque and power of Honda Beat 2013 motorcycles. (3) Knowing the best configuration of Step Up Voltage and fuel variations on the torque of the 2013 Honda Beat motorcycle. The research method used is experimental. The data of this research was obtained by measuring the sample of Honda Beat 2013 motorcycle. The independent variable was the use of Step Up Voltage with a voltage variation of 13.7 V to 14.7 V with a range of 0.2 V with Pertamax and Pertalite fuel. The dependent variable is the maximum torque of the axle and the maximum power of the axle which is measured using a dynamometer. The data obtained were then analyzed using a comparative descriptive technique by describing the data in the form of graphs, statistics and tables. From these data, a comparison is made between groups of data. The results of this study are: (1) The use of Step Up Voltage can increase the torque and power of the Honda Beat 2013 motorcycle. The largest increase in torque is at a voltage setting of 13.9 V with an average increase of 0.44 N.m from standard conditions. The average maximum power increase of the largest axle is at a voltage setting of 14.1 V, which is 0.30 HP from standard conditions. (2) The use of Pertamax fuel can increase the torque and power of the Honda Beat 2013 motorcycle. The average torque produced is 19.98 Nm, an increase of 0.26 Nm from pertalite fuel and produces an average power of 7.47 HP, an increase of 0.34. HP of pertalite fuel. (3) The best configuration is obtained from the use of a 13.9 V Step Up Voltage combined with Pertamax fuel. Torque increased by 0.44 N.m from standard conditions to 20.41 N.m and power increased by 0.20 HP from standard conditions to 7.67 HP

The purpose of this study is to develop composite learning practicum module based on project based learning at hand lay-up fabrication materials. This study means to fulfill the needs of composite subject at Mechanical Engineering Education Department in Faculty of Teacher Training and Education Sebelas Maret University. The method used in this study is the development based on the ADDIE (Analysis-Design-Development-Implement-Evaluate) model. Students of Mechanical Engineering Education Department are subject of this study. Questionnaire technique is used for Data collection. This method and technique are carried out to assess the development of composite practicum module content in terms of material, pedagogic, and language. Quantitative analysis techniques was conducted based on the the answers to the questionnaires. This study have an outcome to make even better composite practicum module with enhanced material, pictures, and evaluation. The rating score obtained from subject is 47,61 with very good criteria. The conclusions of this study are: (1) the development of composite learning practicum module based on project based learning has been done with eligibility standard. Therefore, it suitable as a guidebook for doing a proper composite practicum at Mechanical Engineering Education Department. (2) the developed composite learning practicum module has been done through FGD with lectures, then it being implemented on composite practicum activities, and it was rated by subject with average score 47,61 out of 52 that shows very good criteria. This developed practicum module is expected as a guidebook to help students doing proper composite practicum from preparation, analysis, self manufacturing, and able to improve abilities and skills.

The vortex turbine is a moving turbine using artificial whirlpools that will then be converted into alternate energy turbines on the axis. The purpose of this study is to find out how high the Angle of skeleton tilt and dissipation of water affects the electricity and efficiency generated by vortex's water turbines. This study is using experimental methods. The study involves a few steps by preparing water turbines, sets up tools, data retrieval, and data analysis. The research free variable is a variant of the Angle of the skeletal tilt at 0, 5, 10 and a discharge of water at 6.34 l/s, 7.41 l/s, and 8.29 l/s. The bound variables of research are vortex's type of electric power and electricity efficiency. The research control variable is vortex turbine blade and vortex water turbine. The research instrument used is multimeter-based arduino, flowmeter-based arduino, tachometer, bow and digital balance. Data analysis techniques using quantitative descriptive analysis. The test conducted based on variations of water discharge at 6.34 l/s, 7.41 l/s, and 8.29 l/s and skeletal variant turbine gradient at 0, 5, and 10 of the power and efficiency of the turbines generated. Research shows that the maximum data of electrical calculation is obtained on water-discharge at 8.29 l/s with a tilted point 10 which was 10.3 watts, while the maximum efficiency data is obtained on water-diacharge at 8.29 l/s with a tilted point 10 which was 42.9%.

Hydroelectric power is one of the options in utilizing renewable energy. The generators that are made usually use waterfalls. Low water flows such as rivers have not been utilized optimally. This becomes a reference for utilizing river flow by turning it into a whirlpool or vortex flow. This study analyzes the effect of variations in the number of blades and the distance between the blades and the outlet on the electrical output power of a vortex type water turbine. The research method used is experimental. The independent variables are variations in the number of blades 2, 3, and 4 and variations in the distance between the blades and the outlet 4 cm, 6 cm, 8 cm, and 10 cm. The dependent variable of the research is the output power and efficiency of the vortex type water turbine. Data analysis techniques using quantitative descriptive analysis techniques. The results showed that the maximum data for calculating the electrical output power and efficiency with a water discharge of 6.34 L/s was obtained at the number of blades 4 and the distance between the blades and the outlet 6 cm, namely 9.72 Watt and 65.77%. Based on these results indicate that the more the number of blades, the higher the electrical output power produced. Meanwhile, the variation of the distance between the blade and the outlet increases at a height of 6 cm and relatively decreases at a height of 8 cm and 10 cm.

The needs of electrical energy particularly in Indonesia is very great and continues to increase every year. The development of a micro scale horizontal axis wind turbine can be a solution to solve that. This research has a purpose to find out the influence of number of blades and wind speed variation on electrical energy produced by micro scale horizontal axis wind turbines. The method which was used in this research was experiment method and it was implemented at the Laboratory of Study Program of Mechanical Engineering Education of Sebelas Maret University. The variable that was used in this research was by using blades with airfoil SG6043 with variations of blades number and the giving load in the form of 12v and 24v LED lights. The horizontal axis wind turbine rotor has a diameter of 800 mm and a blade length of 400 mm which is printed with 3D Printing PLA material. The data collection was implemented on the wind speed of 1 m/s to 5 m/s. The results of this research is the wind turbine that used 5 blades produced the highest power of 9.22 Watt at 24v loading and had the highest power performance value of 0.241 at maximum wind speed of 5 m/s. The number of blades and wind speed and loading could affect the electrical power produced by the turbine, the more blades and the higher the wind speed, the greater the power generated by the turbine.

The Raque Hilsch Vortex Tube (RHVT) is a heat pump system that uses the phenomenon of compressed vortex airflow in a tube for cooling and heating. This study aims to determine the effect of pressure and fraction on RHVT by cooling the surface of the hot tube naturally and forcefully. Tube type testing was conducted with a pressure variation of 0.5–1.5 bar and a fraction of 30%–70%. The results of the analysis show that forced cooling on the surface of the hot tube decreases the heating performance ( T h , Δ T h , Q ˙ h , η i s h , and C O P h ) and improves the cooling performance ( T c , Δ T c , Q ˙ c , η i s c and C O P r e f ). The higher pressure increases the performance of T h Δ T h , Q ˙ h , T c Δ T c , and Q ˙ c , and decrease the performance of η i s h , C O P h , η i s c , and C O P r e f . The fraction 40% is the most optimal parameter for the performance of T c Δ T c , Q ˙ c . The 60% fraction works best for T h , Δ T h , Q ˙ h , η i s h , and C O P h , while the fraction 70% works best for Q ˙ c and C O P r e f . The most optimal performance values include T h (41 °C), Δ T h (14 °C), Q ˙ h ( 2.369 kJ / s ) , η i s h ( 24.21% ) , C O P h (0.092), T c (13.450 °C), Δ T c (13.550 °C), Q ˙ c ( 3.280 kJ / s ) , η i s c (20.84%), and C O P r e f (0.123).

Purpose The purpose of this paper is to experimentally investigate the effect of biodiesel fuel blending and heating on engine torque and power. Design/methodology/approach To obtain torque and power data, a 1200 AWD dynamometer was used. The 1200 AWD dynamometer is a device used to obtain readings, and is made up of a chassis, inertia roller, roller sensor and converter modules, and can also be connected to a personal computer. Findings The result revealed that biodiesel blending and heating significantly affected torque and power. When only biodiesel blend ratio was varied, the highest torque and power were obtained at 30 per cent fuel blending. Also, the highest torque and power were obtained at 20 mm when only a spaced finned tube heater was used. When both variables were combined, the highest torque was obtained at a 20 per cent biodiesel blend and a 10 mm radial radiator finned spacing. Maximum power for two variables was obtained at the 20 per cent blend ratio and 20 mm finned tube heater spacing. Originality/value A novel radial finned tube heater is used.

Development of an efficient irrigation supplying precise amount of water can have benefits not only by reducing the operating costs but also by enhancing the dry land productivity. In the area with limited water resource, drip irrigation method provides advantage by minimizing water loss due to percolation, evaporation and surface flow. This article presents installation of a drip irrigation system for dragon fruit farmland in Nguntoronadi, Wonogiri, Indonesia. The water requirement of dragon fruit has been determined using the Cropwat software based in the local climate and field conditions. This data is required to determine the irrigation operation time each day. In evaluating economic feasibility of this irrigation system, a cost analysis was performed based on the site technical requirements. It is expected that the drip irrigation implemented will increase the total production of a rain fed farmland.

Development of an efficient irrigation supplying precise amount of water can have benefits not only by reducing the operating costs but also by enhancing the dry land productivity. In the area with limited water resource, drip irrigation method provides advantage by minimizing water loss due to percolation, evaporation and surface flow. This article presents installation of a drip irrigation system for dragon fruit farmland in Nguntoronadi, Wonogiri, Indonesia. The water requirement of dragon fruit has been determined using the Cropwat software based in the local climate and field conditions. This data is required to determine the irrigation operation time each day. In evaluating economic feasibility of this irrigation system, a cost analysis was performed based on the site technical requirements. It is expected that the drip irrigation implemented will increase the total production of a rain fed farmland.AbstrakSalah satu upaya peningkatan produktivitas lahan kering adalah dengan pengembangan irigasi suplementer hemat air pada musim kemarau. Pada lahan dengan sumber air terbatas, sistem irigasi tetes dapat menghemat pemakaian air karena dapat meminimumkan kehilanganan air yang mungkin terjadi seperti perkolasi, evaporasi dan aliran permukaan. Artikel ini ditujukan untuk melakukan analisis implementasi sistem irigasi tetes pada lahan budidaya tanaman buah naga di wilayah Kecamatan Nguntoronadi Wonogiri yang memiliki topografi perbukitan dengan karakter tanah kering. Kebutuhan air tanaman dan laju aliran penetes digunakan sebagai dasar untuk menetapkan waktu operasional sistem irigasi. Analisis kelayakan teknis menunjukkan bahwa sistem irigasi tetes layak diterapkan di untuk budidaya tanaman buah naga di lahan kering. Analisis biaya dilakukan untuk menguji kelayakan ekonomis implementasi teknologi tersebut. Dibandingkan sistem irigasi manual, sistem irigasi tetes berdampak pada penghematan biaya yang akan berpengaruh pada keseluruhan biaya operasional budidaya tanaman buah naga.

This research aims to determine the effect of the variations use of starch adhesive on the RDF-5 burn time from coffee ground and sengon sawdust. The method used in this research is experimental. Independent variables in this research are ratio of variations in composition of the ingredients are 0:100, 30:70, 50:50, 70:30, 100:0 and variations in concentration of adhesive are 10%, 20%, 30%. Dependent variables in this research is burn time. Control variables in this research are mesh, pressing pressure, and the resulting RDF-5 dimensions. This research was conducted in the Mechanical Engineering Education Laboratory of the UNS in Campus V. Data collection of burning time using stopwatch and blower. The longest burn time was found in 100:0 composition variation and 30% adhesive concentration. The result of research showed that the longest burn time produced by RDF- 5 which uses the most starch adhesive.

This paper investigates a fluidized bed boiler used in an ethanol production plant. The boiler uses biogas fuel produced by the waste system of the distillation unit within this ethanol plant. Using Engineering Equation Solver (EES), a mathematical model is developed by employing the exergy analysis. Before the study was undertaken, initial operating data of the components in the plant was collected. The results show that the boiler system has an overall efficiency of 68.238 %. The exergy efficiency in each component was also calculated. The evaporator and heat exchanger have the lowest efficiency at 45.97% and 28.96%, respectively. The efficiencies of the other components are 61.41% for the pump water pit, 54.42% for the soft water tank and 66.39% for the de-aerator.

This research aims to evaluate the performance of a fluidized bed boiler in an ethanol production plant through exergy and irreversibility analysis. The study also includes the optimization of the pre-heater and the deaerator in order to improve the system efficiency. Operational data from the ethanol production plant was collected between 2015 and early 2016. The total exergy derived from the fuel was determined to be 7783 kJ/s, while the exergy efficiency of the system was found to be 26.19%, with 2214 kJ/s used in steam production, while 71.55% was lost to component irreversibility and waste heat from the pre-heater. The exergy efficiencies of individual components of the system such as the boiler, deaerator, and pre-heater were found to be 25.82%, 40.13%, and 2.617%, respectively, with the pre-heater having the lowest efficiency. Thus, the pre-heater has the highest potential to significantly improve the efficiency of the boiler system. The optimization of the pre-heater shows that a rise in temperature in the outlet of the pre-heater positively affects the exergy efficiency of the deaerator.

The main objective of this research is to investigate the effect of attaching nozzle lens with difference diameter and number of blades in non-twisted NACA 4415 on the power output of the Horizontal Axis Wind Turbine (HAWT). The Artificial of low wind speed were used in this experiment at 2.5 m/s, 3.5 m/s, and 4.5 m/s. The result shows that the lenses increase the power output. The lens diameter is directly proportional to the rotor speed and TSR of the turbine. In the difference number of blades, the three-blades turbine consistently generates the highest power output compared to two-blades and four-blades turbines. The evidence has established that nozzle lenses and three-blades turbine can successfully increase the efficiency of wind turbines in areas where wind speed is low.

Utilization of durian shell waste as feed biomass in the pyrolysis process has been carried out. The results of the pyrolysis process produce bio-oil, gas, and biochar. Pyrolysis biochar can be used as a potential source of energy by converting it into biochar briquettes. This research is making biochar briquettes using a mixture of water and starch. The ratio between biochar and starch is 9: 1. The mixed material is then made biochar briquettes using a briquette printer with a pressure of 0.5 MPa. The results showed that biochar briquettes had better performance than durian shell biomass.

Wind turbines are devices that convert wind kinetic power into electrical energy through generators. Currently there has been a lot of research on horizontal shaft type wind turbines to improve systems that work optimally. This study uses a 3 blade horizontal winglet wing turbine wind turbine with variations in pitch angle to increase the cut in speed value. The pitch angles used are 0°, 2°, 4°, 6°, 8°, and 10°. This study uses an NACA 4412 aerofoil with winglets added to the blade tip. The research method used in this study is the experimental method. The results showed that the highest cut-in speed values of three, four and five blades were obtained at a pitch angle of 10° at wind speeds of 2.3 m/s, 1.8 m/s and 1.8 m/s.

The characteristics of B20 biodiesel droplet combustion on flame propagation rate at microgravity conditions are fascinating to study. The observation of Biodiesel B20 fuel was chosen because it supports the Indonesian government policy on the use of alternative energy. This research is an initial stage to determine the effect of variations in the speed of motion of biodiesel B20 droplets on the flame propagation distance. At this initial stage, the droplet velocity is set at 5 mm / s. There are three droplets used, namely droplet A (igniter droplet), droplet B (flame source droplet), and droplet C (observation droplet). Each droplet has a diameter of 1 mm. Data was collected directly through video analysis to determine the propagation distance of SBC/d0. The results showed that the investigative droplet (C), which was 3 mm from droplet B, had a maximum burnt distance of SBC/d0 = 4 - 4.2.

This research was aimed to analyze the effect of adding pitch angle to the performance of a Savonius Hybrid Type S-Darrieus Type H-Rotor wind turbine with variations in wind speed. This research used an experimental method with variations in pitch angle and wind speed. Variables taken in this study are wind speed, pitch angle addition, and wind turbine cutting speed. Variations in the addition of pitch angles are 0°, 5°, 10°, 15 °, 20°, 25°, 30°. The results showed that the addition of pitch angles to the blade influenced the cut in speed. The highest cut in speed is 4.2 m/s at the addition of pitch 0° while the lowest cut in speed is at 3.8 m/s at the addition of a 30° pitch angle.

The coastline of Demak city shows an increase in the need for electrical energy every year, in line with an increase in pond production. Currently, electricity needs are supplied from diesel generators. However, the use of diesel generators as electricity generators causes pond production costs to increase. On the other hand, the coastal location of Demak has wind potential, which can be used as a power plant. In this study, a numerical study was carried out using the savonius wind turbine as a power plant in the coastal area of Demak city. This research’s initial stage was to collect data on wind characteristics during the day and night conditions. Wind speed data are then used as input parameters in the numerical simulation using the ANSYS R.15 software. This study compares simulations between Savonius wind turbines without using fins and using fins for placement on the coast of Demak. The simulation results show that the wind speed on the coast of Demak ranges from 2 to 3.5 m / s. In these wind conditions, the savonius wind turbine with one fin has a power coefficient (Cp) better than without the fin. The relationship between wind speed and the electric power produced has been simulated and discussed in depth in this paper.

Energy demand in the form of portable devices to supply electronic equipment increases every year. Micropower Generator is an alternative solution for portable energy generation. The most crucial component in micropower generation is micro-combustion. The problem faced in micro-combustion is the presence of a stable flame in the combustor. This study aims to produce flame stability on the combustor by using several fuels such as acetylene gas and propane gas. The micro combustor used in this study is a cylinder type with an inlet diameter of 3.5 mm, an outlet diameter of 4.5 mm, and a wall thickness of 0.5 mm. The micro-combustor is made of stainless steel with a burned region of 10 mm and an unburned region of 40 mm. The results showed that the combustor wall’s temperature with propane fuel reached the highest average temperature at 182.45°C, while 113.20 °C for acetylene fuel.

The effect of global warming has raised public awareness to seek energy sources that do not damage the environment and can be renewed, such as renewable energy. Renewable energy that is practically applied in people’s homes, namely sun and wind. This research studies about solar panels to determine the highest electrical power produced. Measurements are made by measuring the voltage and electric current generated by solar panels and measuring wind speed to determine the electrical power generated by wind turbines. This research was conducted in the Campus area of Universitas Sebelas Maret Surakarta. Solar panels produce the highest electric power of 26.42 Watts. This study states that solar panels produce electric power that is more effective and optimal than wind turbines. The power produced by the solar panels is 26.42 Watt, while the wind turbine produces electric power of 6.46 Watt.

The objective of this research is to investigate the reduction in fuel consumption and emission in spark ignition engine using blended bioethanol-gasoline and novel radiator-tube heater. Different percentages of ethanol – 0, 5, 10, 15, 20, 25 and 30% – are employed. The blended fuel is then pre-heated by sending it into a tube-heater-installed upper tank radiator which has different shape. The results show a significant reduction in fuel consumption and emission in engine. The best economical fuel consumption occurs in the tube-heater with a fin pipe of 10 mm space at 2.153 × 10−3 cc per cycle or 5.632%. However, the most economical fuel consumption occurs when 25% of bioethanol is added to fuel at 3.175 × 10−3 per cycle. This decreases fuel consumption by 8.306%. The highest decrease in fuel consumption occurs when fuel blended with 25% of bioethanol and tube-heater of 10 mm 6.236 × 10−3 cc per cycle or 16.313% is combined. In terms of emission reduction, the tube-heater with a space of 20 mm bet...

The binary power plant is a geothermal power generation system used at low to medium temperature levels and used indirect system. In this system, the heat generated from the reservoir is channelled to the secondary working fluid which has a lower boiling point than water using a heat exchanger. In this case, the Organic Rankine Cycle (ORC) is a suitable system for use. This improves the performance and efficiency of the plants. However, in this system, the installation configuration of the ORC model is an important factor that can affect its performance. The selection of an improper ORC design reduces the thermal efficiency of the system. Therefore, it cannot utilize heat optimally. In this study, Engineering Equation Solution (EES) simulation program is used to run the system as in operation conditions. A comparative analysis is conducted using ORC, Regenerative ORC (RORC), and RORC with Internal Heat Exchanger (IHE). The results indicate that RORC with IHE has the greatest value for both energy (21.74%) and exergy efficiency (25.26%) while net power produced 5479 kW. This shows the addition of OFOH and IHE can increase these factors, improve performance and reduce energy degradation from the cycle.