Application of Computational Fluid Dynamics Method for Cross-flow Turbine in Pico Scale

Crisis electricity was a crucial issue in the rural area. Crossflow turbine (CFT) in pico in pico scale is the best option for electricity provider for rural areas. Due to its usefulness and development of computer technology, computational fluid dynamics method application for CFT study becomes increasingly frequent. This paper compiles the implementation of the computational fluid dynamic (CFD) approach for CFT on a pico scale. Based on the literature, the Renormalization Group (RNG) turbulence model is recommended to predict the flow field that occurs in CFT because its error is lower than others turbulence models, the RNG error of 3.08%, standard of 3.19%, and transitional SST of 3.10%. Furthermore, six-degrees of freedom (6-DoF) is recommended because it has an error of 3.1% than a moving mesh of 9.5% for the unsteady approach. Thus, based on the review, the RNG turbulence model and 6-DoF are recommended for the CFT on the pico scale.

Measuring Feed Force in Machining Using a Strain Gage

Measuring the forces that work during machining has been being concerned by researchers for years. There are three main forces that work in turning: thrust force, axial force, and radial force. Thus, feeding force measurement is needed in machine manufacturing. This research attempts to develop measurement method through feeding force, using strain gauge sensor. The aim of measurement of feeding force in this research is to find out the influence parameter of machine towards feeding force. The research used experimental method with design experiment Taguchi to know the influence of machine parameters to feeding force in turning process. The measurement tool is strain gauge sensor connected to cutting tool. The workspace is alluminium 6061 with 15 mm in diameter and 150 mm in length. The parameters for this research are speed rate (140 rpm, 215 rpm, and 330 rpm), feed rate (0,043 mm/r , 0,065 mm/r , and 0,081 mm/r), and depth of cut (0,2 mm, 0,4 mm, and 0,6 mm). The result showed that speed rate is the most significant parameter, with the contribution percentage is 92 %. Speed rate and feed rate parameter have insignificant influence. The contribution percentage of speed rate is 2% while the feed rate has % contribution percentage. The conclusion of the research is that the bigger number of speed rate, the bigger feeding force it will have.

Literature Studies on Maintenance Management

The purpose of this paper is to review from early days until recent time the development of maintenance management methods from maintenance textbooks to give a glance view for researcher and practitioner where maintenance start until recent development and practical application of maintenance management. The methodology approach is by reviewing an early age maintenance management, maintenance management on eighties, maintenance management on nineties and recent maintenance management. Comparing and categorizing maintenance management methods along with time will increase knowledge how to choose the right maintenance for practical application. From this review it found that the paper also revealed from time to time, maintenance management adapt and improve to gain more sustainable maintenance, including the new shift of paradigm of maintenance itself. The originality and contribution of this research is that the paper contains many maintenance management methods from maintenance textbooks, maintenance management methods elaborated in an easy way. Therefore, the importance of maintenance management could be properly understood. For further study, the paper suggest that research needed to study or apply on methods found in this paper on practical application whether will give a proper result or just nice on theoretical only.

Numerical Study on the Characteristics of Air Flows through Helmet Bicycle Racing Using the Effect of Variation of Trailing Edge

Research on aerodynamics on racing bicycles always develops from time to time. The various geometry of a time-trial helmet produces different characteristics of fluid flow, this is due to the relative movements of air that are in the area throughout the body shape of the helmet. Basically the fluid flow that passes on a racing bicycle helmet will produce a drag force, where this must be minimized in order to hinder the pace of drivers to achieve maximum speed, so drivers should pay attention to how to design the geometry of helmet that should be used. Computational fluid dynamics (CFD) method is used to simulate the case studies in this research. In this study, four kinds of models trailing edge geometry was varied to determine where the most optimal in accepting the drag force. The validation was also conducted to determine the suitability of this study with prior research, where in this validation the results of this study are compared with the research owned (Sims and Jenkins, 2011). The results of this validation show that the resulting drag coefficient has a very small difference of 0.001. The four models are simulated with Reynold number values of 7.14 × 104, 1.00 × 105, and 1.16 × 105. The results of this study indicate that with differences in the geometry of the trailing edge affect the drag force that occurs. From the research result when Reynold 7.0 x 10 ^ 4, the drag force produced by model 3 is bigger than model 1 and 2 which is equal to 0.182 N. Whereas on Reynold which is bigger 1.16 x 10 ^ 5 model 3 receives drag smaller than model 1 and 2 which is equal to 0.283 N. In the world of bicycle racing, the difference in the small drag force affects the speed of the bicycle and affects the resulting victory.

Feasibility Study on a Micro Hydro Power Plant at Coban Jahe Waterfall, Jabung, Malang Regency

Micro Hydro Power (MHP) Plant is a small-scale power plant under 100 kW. Generally, MHP is built in a place that the electricity network has not touched. Many waterfalls in Taji Village are only used as tourist attractions. One of them is Coban Jahe waterfall which has a water discharge of 0.60567 m3/s in the dry season. Waterfall in Coban Jahe was used and planned as Micro Hydro Power Plant, it was called as MHP. Potential electric power generated from the MHP Coban Jahe Waterfall is 14.0368 kW with an effective head of 3.4742 m. The results show from the financial analysis, the construction of MHP is quite feasible with NPV of Rp. 45,676,769, BCR of 1.0852, which means it is feasible to be continued, the Payback Period is 9 years which does not exceed the project life, and the IRR obtained is 10,0087% which the projects are feasible and profitable to build.

Mechanical Properties of Layered-Carbon Fiber Reinforced with Vacuum Infusion Process

Research on material engineering is widely developed in the precursors, composition of the material, and technique to create a composite. The layering and vacuum infusion resin are the developing technology to create the composites with the new characteristics and properties. This experiment is intended to find out the characteristics of layering carbon fiber reinforced by resin and is molded with vacuum infusion technique. The specimens of this experiment is layered-carbon fiber composites determined in three, four, five, six, and seven layers. The precursors of 220 and 240 carbon fibers are the main material of the composites. The tests conducted to the specimens are bending and tensile tests. The both tests are treated to reveal the mechanical properties of the composites. The least layers of 220 and 240 carbon fiber result the highest value of bending test, but the most number of carbon fiber layers show the opposite value. The results are reverse in the tensile test. The highest value of the tensile test is achieved by the most layers of carbon fiber, while the lowest value is in the least layers. This result is almost the same with the strain-stress, but overall the graphic is similarly increase to the most layers. Deduction achieved in this experiment is that the number of layers in the carbon fiber composites is significantly influencing the mechanical properties of the composite.

Honeycomb-Shaped Brass Plate Catalyst to Reduce Motor Vehicle Emissions

The increasing number of motorized vehicles has a direct impact on exhaust gas air pollution. The air pollution in urban areas is dominated by motorized vehicle emissions, along with pollution problems. This study aims to reduce motor vehicle emissions by using a catalytic converter design made from a brass plate catalyst in the shape of a honeycomb. Honeycomb-shaped brass is suitable for catalysts in the catalytic converter. Besides being easy to obtain and cheap in price, the catalyst can reduce and oxidize exhaust gases well, making it suitable as a catalyst material. The method used in this research is the experimental method. It is started from the design of the catalytic converter house and determining the type of catalyst to the process of making the catalytic converter with a honeycomb-shaped brass plate. Then, testing to determine the emission of exhaust gases produced is required. The last step is to compare it without using a catalytic converter or standard conditions. From the results of the emission test, it was found that the use of a catalytic converter made from a brass plate catalyst in the shape of a honeycomb can reduce HC and CO emissions, while CO2 emissions have increased. A decrease in HC gas emissions by 19.1% for a single catalytic converter and 33.7% for a dual catalytic converter is better compared to without using a catalytic converter or standard conditions. Reduced CO gas emissions by 23.8% for a single catalytic converter and 43.1% for a dual catalytic converter are compared to without using a catalytic converter. Meanwhile, CO2 gas emissions increased by 60.7% for a single catalytic converter, and 81.6% for multiple catalytic converters are compared without using a catalytic converter. This is a result of the addition of oxygen to the oxidation process that running smoothly.

Preliminary Design of Wellhead Spacer Spool Based On the API Acceptance Criteria

In the case of assembly wellhead, a spacer spools was used to provide space and connect between parts of the wellhead. In order to design spacer spool with specified material should comply the standards and procedures of the oil and gas industry. The results of the material calculation were using the ASME BPVC guidelines. These three materials strengths were calculated if used as a body spacer spool. Based on acceptance criteria on API 6A 21st Edition, these three materials were categorized as acceptable to be used as a body spacer spool for this specification. These three materials strengths were also calculated the stress of the flange and flange rigidity criteria. Based on the acceptance criteria on ASME BPVC guidelines, the results showed that these materials can be used for flange because it had stress value under yield strength of material which was flange rigidity criteria for operating condition has 0.59 and 0.66 for testing condition because had value of rigidity that met with minimum acceptance criteria.

Utilization of Air Conditioning Heat Waste as Cloth Drying Energy Source

Air Conditioning (AC) as an air conditioner has been used on one side only as a room cooling. The cooling process with Air Conditioning produces heat as a result of the work of the condenser component in the AC. This heat can be used as an alternative energy source. This study aims to utilize hot air discharging Air Conditioning as an energy source for drying clothes. This development is based on the Thosiba AC specification. The specification data is used to get the coefficient of performance (COP) and heating effect. Development is also carried out for studies in the form of experiments. The results of the study indicate that the application of AC exhaust heat has the potential to be developed as an alternative energy in the process of drying clothes.

The Effect of Agitation Parameter on Hardness and Thickness of Decorative Nickel-Chrome Coating on A36 Steel using Electroplating Process

Electroplating is a process of settling substances (metal ions) on the electrodes (cathodes) using electrolysis. The occurrence of a precipitate in this process is due to the presence of electrically charged ions moving from an electrode through the electrolyte, the result of the electrolyte will seal on another electrode (cathode). During the process of deposition/deposit takes place a chemical reaction occurs at the electrode and electrolyte both reduction in a certain direction permanently, therefore it requires direct current and a constant voltage. Metal coatings commonly used are copper, nickel, chromium, and others. Electroplating is basically to coat the metal to make it look more attractive and protected from corrosion, and can increase the product's resistance to friction. The purpose of this study was to determine the effect of stirrer rpm variations on the thickness and thickness of the A36 steel layer in the decorative nickel-chrome electroplating process. 4 specimens in this study were 30x30x2 (mm). Nickel and chromium coatings have variations in the speed of 72, 102, 132, and 162 (rpm) with a time immersion of 22 minutes and with a temperature of 55-60 ° C. The results of this electroplating process were tested by Vickers's hardness test and observation of microstructure results. The results showed that the faster the rpm, the more hardness was obtained which increased and the thickness of the layer increased. The highest hardness and thickness values are found at a rotational speed of 132 rpm. With a hardness value of 77.5 VHN and a thickness value of 4.55 µm (Nickel) and 13.76 µm (Chrome).