Dominicus Danardono Dwi Prija Tjahjana

Bio: Dominicus Danardono Dwi Prija Tjahjana is an academic researcher from Sebelas Maret University. The author has contributed to research in topics: Turbine & Wind speed. The author has an hindex of 7, co-authored 65 publications receiving 182 citations.

Performance of the drag type of Horizontal Axis Water Turbine (HAWT) as effect of depth to width ratio of blade

Abstract: Application of wind turbine to the water turbine is an interesting topic because of different energy momentum. A Horizontal Axis Water Turbine (HWAT) was proposed to produce energy in building the pipeline. A preliminary study using simulation and experimentally study of depth to width ratio of the blade was examined in order to determine optimum performance of the turbine using several variations of depth to width ratio of the blade with a constant head of 2 m and angle of the blocking system of 30°. Effect of the existing of different depth to width ratio of the blade for debit was reported. The optimal performance of the turbine was obtained at depth to width ratio of 0.29 that shown by highest obtained voltage of 8.62 Volt, the power output of 3.447 Watt and coefficient power of 2.73×10−2.

Adhesive nanosilica/aluminium powder — Epoxy for joint application on composite car body of electrical vehicle

Abstract: The objective of this research is to investigate the comparison nanosilica and aluminium powder in epoxy as adhesive on shear strength of single lap joint between aluminium-GFRP composite. The shear strength was determined by utilizing the single-lap shear test. The nanosilica content was varied in 0, 1, 2, 3 and 4 (w/w), whereas the content of aluminium powder was varied in 15, 20, 25, 30 and 35 (w/w). Experimental results showed that the nanosilica-epoxy adhesive has the maximum shear strength at 2 % nanosilica content. However, for the use of the aluminium powder-epoxy adhesive, the shear strength decreased significantly along with elevated level of aluminium powder. The adhesive failure mode occurres the joining using nanosilica-epoxy as adhesive, and the joining using aluminium powder-epoxy as adhesive is categoried as cohesive failure mode. The cohesive failure mode has higher shear strength over adhesive failure mode.

The Influence of Guide Vane to the Performance of Cross-Flow Wind Turbine on Waste Energy Harvesting System

Abstract: The purpose of this experiment is to know the influence of a single guide vane position and angle to the performance of a cross-flow wind turbine. The cross-flow wind turbine was positioned at the discharge outlet of a cooling tower model to harness the discharged wind for electricity generation. A guide vane was used to enhance the rotational speed of the turbines for power augmentation. Various position and angle of attack of the guide vane were tested in this experiment. To avoid negative impact on the performance of the cooling tower fan and to optimize the wind turbine performance, the turbine position on the discharge wind stream was also studied. The result showed that cross-flow wind turbine with a guide vane attached at the right position had a higher coefficient of power than cross flow turbine without guide vane. A crossflow wind turbine with the guide vane at the position of 150 mm from the center and 30° angles had the highest coefficient of power of 0.49. Comparing to the wind turbine without guide vane, the coefficient of power of the cross-flow wind turbine was increased about 84.3%.

Slow pyrolysis of selected agricultural wastes: analysis of thermal degradation behavior

Abstract: The use of fossil fuels produces carbon dioxide (CO 2 ). Carbon dioxide is one of the greenhouse gasses that contributes to global climate change. Due to this issue, there is increasing the requirement for the use of renewable materials and development of the additional sustainable process. Agricultural waste that has the property of fast growth, is an alternative renewable energy. In this work the slow pyrolysis of selected agricultural wastes mixture (cassava peel-rice straw, rice straw-rice husk, and cassava peel-rice husk) were studied to determine thermal degradation behavior of the biomass. The process was conducted in a fixed bed reactor at temperatures 325 °C, at 10 °C/min heating rate and at 10 min holding time. Results revealed that the moisture content of agricultural wastes were 4.40 % (cassava peel-rice husk), 5.48 % (rice straw-rice husk) and 8.12 % (cassava peel-rice straw). The devolatilization process of the biomass was taken place in the temperature range from 189 o C to 325 o C. The volatile matter of each sample was 61.5% for cassava peel-rice husk, 58.5 % for rice straw-rice husk and 52.5 % for cassava peel-rice straw.

Failure Analysis of Super Hard End Mill HSS-Co

Abstract: Abstract The failure of tools will make a large impact to the productivity, so it must be investigated to avoid the next failure. In this case, the super hard end mill HSS-Co list 4SE code 6210 was broken when it was used for side milling processing of mild steel AISI A36 with rotation speed, cutting speed and cutting depth of 540 rpm, 0.10 m/min (4 ipm) and 16 mm respectively. Standard procedure of failure analysis was performed including macro-micro investigation using Scanning Electron Microscopy (SEM) with energy-dispersive spectrometry (EDS) attachment, micro hardness test, and Finite Element Methods (FEM) simulation. The results of failure analysis showed that fracture occurred due to stress concentration and micro defects of the super hard end mill. Two parts of fracture surface, rough and fine surface were found. Based on SEM-EDS investigation, it was known that the content of tungsten (W) and cobalt (Co) elements on the rough and fine surface was inhomogeneous. Excessive Co and W elements appeared on the fine surface while they disappeared on the rough surface. Excessive Co will diffuse with tungsten and carbon and lead to the separation of tungsten and carbon elements, so it greatly destroyed the alloys and lead to form the non-stoichiometry carbide points. Hence, the defective manufacturing processes which made the elements distribute inhomogeneous is concluded as the reason of the super hard end mill failure.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The solutions to electric vehicle air conditioning systems: A review

Abstract: The air conditioning (AC) system provides cool, heating and ventilation in the cabin of the electric vehicles (EVs). It is necessary to control the interior thermal environments of the vehicle and ensure safety in visibility. Because AC systems are electrically powered, vehicle range is reduced drastically when the AC system is operating. EVs present a particular challenge to the development of more efficient AC systems for automotive applications. In this paper, the state of the art for various AC system solutions to EVs was critically reviewed. The investigations of alternative solutions are continuing along many parallel routes, e.g. vapor compression refrigeration-dedicated heater AC systems, reversible vapor compression heat pump AC systems, non-vapor compression AC systems and integrated thermal management system combined AC and battery pack. The characteristics and particular applications of each solution have been extensively discussed. Finally, a comparison listing the various pros and cons of the different available solutions was presented.

Study the influence of using guide vanes blades on the performance of cross-flow wind turbine

Abstract: A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio; therefore, it is a good candidate for a self-starting turbine. This study aims to investigate the best configuration between guide vanes and cross-flow vertical axis wind turbine. The experiment test was carried out to determine the turbine with the highest power coefficient. The cross-flow turbine has 14, 18, and 22 blades with using 6,10 and 14 blades of guide vane (GV) was developed in this study, employing 15°, 25°, 35°, 45°, 55°, 65°, and 75° of tilt angles in fifth different wind speed conditions 4 m/s, 6 m/s, 7.5 m/s, 9.20 m/s, and 11 m/s. The turbine has 22 blades with 14 GV blades at 55° of tilt angle blades producing more remarkable turbine performance improvement than other blades. The highest power coefficient (CP) of cross-flow using 14 GV blades at 55° was 0.0162 at 0.289 TSR, which increased around 59% of the turbine's performance using GV.