Pendekatan Analitis Dan Simulasi Komputer Desain Blok Kaca Rendah Energi

Analytical and Computational Simulation Approaches to Design Low Energy Glass Block. An environmentally friendly process was developed to produce a low embodied energy glass block from waste glasses. The energy efficiency of the glass block is represented by its thermal conductance (U) <3.177 W/m2.K and solar transmittance (SHGC) ≤0.25 as well as visible light transmission (VT) ≥0.27. A cavity was applied to reduce U value while insignificantly reducing VT. Analytical method was used to calculate the U value of glass blocks, ignoring the effect of convection. Ecotect program was used to analyze light level (VT) and heat load (SHGC) of each model. Effect of convection was simulated using a CFD program, which showed air velocity inside the cavity and temperature gradient in glass blocks. Comparing to an application with 3 mm float glass, energy efficiency obtained through applying the glass blocks could reach 96%. This simulation study ignored the presence of adhesive among glass layers that potentially reduces the VT and the SHGC of the glass blocks

Analisa Heat Input Pengelasan Terhadap Distorsi, Struktur Mikro Dan Kekuatan Mekanis Baja A36

The minimization of weld distortion has become an important subject of research in welding. Severe distortion can cause undesirable influence on the cost of fabrication since additional work or repair needs to be performed. In addition, distortion also reduce dimensional accuracy and even loss of structural integrity. The present investigation aims to reduce welding distortion on A36 steel by controlling heat input during Metal Inert Gas (MIG) welding. The welding process was carried out by maintaining constant voltage and current of 23 Volt and 145 Ampere respectively whereas travel speed was varied in the range of 3.9 to 4.9 mm/s giving heat input of 678 to 936 J/mm. Result of this investigation showed that the welding distortion was achieved at the heat input of 756 J/mm. At this heat input, the percentage of acicular ferrite is maximized resulting in good weld impact toughness