Due to the supersonic speed at which propellant gas flows through the gun barrel, a high intensity impulsive sound pressure is created, which has negative effects in many respects. Therefore, the high pressure waves generated due to muzzle blast flow of tank gun during firing is a critical issue to examine. The purpose of this paper is to study and analyze this high pressure impulsive sound, generated during the blast flow. The large caliber 120 mm K1A1 tank gun has been selected especially for this purpose. An axisymmetric computational domain has been constructed by employing Spalart Allmaras turbulence model to evaluate pressure and sound level in the tank gun using Computation Fluid Dynamics technique. Approximately 90% of pressure and 20 dB of sound level have been attenuated due to use of the three baffle silencer at the muzzle end of the gun barrel in comparison to the tank gun without silencer. Also, the sound pressure level at different points in the ambient region shows the same attenuation in the results. This study will be helpful to understand the blast wave characteristics and also to get a good idea to design silencer for large caliber weapon system.

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The lack of wind speed capacity and the emission of photons from sunlight are the problem in a hybrid system of photovoltaic (PV) panels and wind turbines. To overcome this shortcoming, the incremental conductance (IC) algorithm is applied that could control the converter work cycle and the switching of the buck boost therefore maximum efficiency of maximum power point tracking (MPPT) is reached. The operation of the PV-wind hybrid system, consisting of a 100 W PV array device and a 400 W wind subsystem, 12 V/100 Ah battery energy storage and LED, the PV-wind system requires a hybrid controller for battery charging and usage and load lamp and it’s conducted in experimental setup. The experimental has shown that an average increase in power generated was 38.8% compared to a single system of PV panels or a single wind turbine sub-system. Therefore, the potential opportunities for increasing power production in the tropics wheather could be carried out and applied with this model.

The purpose of this experiment is to study the yield of the single basin solar still as an effect of water surface level in sensible heat material in a single basin solar still. The study is conducted on an open floor roof top at the Faculty of Engineering, Muhammadiyah University Prof. DR HAMKA in Jakarta, Indonesia. The study is conducted within two month and use 3 solar stills made of 3 mm Stainless Steel with dimensions 420 mm x 305 mm. The cover is made of 3 mm glass with a slope of 30 degrees. Iron sand that used as sensible heat material is taken from Glagah beach, Kulonprogo in Yogyakarta, Indonesia. 3 solar stills containing 20 mm height of iron sand. The height of the water in the three solar stills is 15mm (V1), 20mm (V2) and 25mm (V3) so that sequentially the surface of the water will be below the surface of the iron sand, the same as the surface of iron sand and above the surface of iron sand. The results obtained show that the daily yield accumulation of V2 is on average 49% higher than V1 while V3 is 57% higher above V1.

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