UTILIZATION OF WASTE BIOMASS BRIQUETTES AS SUBSTITUTION OF KEROSENE IN STERILIZATION PROCESS OF AURICULARIA SP. PLANTING MEDIA

This research aims to study the characteristics of biomass briquette of waste planting medium in the sterilization process of their as a substitute for kerosene. This research also to evaluate the utilization of biomass briquettes in the sterilization process, the performance of water vapor quality in the autoclaf and the combustion efficiency of biomass briquettes. The process of sterilization is one of the important stages in the cultivation process of ear mushroom (Auricularia sp.) in order to make inactive microbes, whether bacteria, fungi and viruses that can disrupt the growth of mushrooms. The process of sterilization required heat energy source to produce vapor temperature above 100 o C. Before the subsidized kerosene withdrawn from the market, mushroom farmers using kerosene fuel. But, currently musroomfarmers use firewood as a source of heat in the sterilization process of ear mushroom planting medium. The research was conducted by briquetting waste of mushroom plantingmedium with dimemsion diameter 5 cm and height 5 cm by using a hydraulic jack. The adhesive material (binder) used molasses with concentration 5-10%. While the autoclaf model for sterilization process is cylinder type with diameter 80 cm and height 120 cm. The autoclaf used steel plate width 3 mm that can restrain high vapor pressure. The biomass briquettes of mushroom planting medium waste was used as fuel for sterilization process in the autoclaf model. The autoclaf model was equipped with pressure relief, pressure gauge and thermometer gauge. The results of this research showed that the calorific value of biomass briquettes at 2224 kcal/kg. The caloric value of this biomass briquettes was lower than caloric value of kerosene at 9000 kcal/kg. Consider the Boiling Water Test method was obtained the rate of combustion of biomass waste briquettes at 40 gr/min. Measurement of flame temperature on the center of the fire produced flame temperatures above 1200 o C. The amount of biomass waste briquettes that needed in one work day (8 hours) reached 19,2 kg. The thermal efficiency of the burning process of biomass waste briquette on the furnace was 14%. The thermal efficiency of the burning process of biomass waste briquette on the furnace was 14%. The steam temperature in the model autoclaf reached 105 o C

SLOW PYROLYSIS OF SELECTED AGRICULTURAL WASTES: ANALYSIS OF THERMAL DEGRADATION BEHAVIOR

The use of fossil fuels produces carbon dioxide (CO2).  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 oC to 325 oC. 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

Analisis Konvektif Two-phase Mixture Model (Eulerian Approach) pada Peningkatan Transfer Kalor Aliran Turbulen Nanofluida Berbasis Dispersi Nanopartikel Metalik Oksida Al2O3

Transfer kalor konveksi nanofluida Al2O3/EG pada pipa berpenampang lingkaran di bawah kondisi fluks kalor dinding konstan telah dikaji secara numerik menggunakan pendekatan computational fluid dynamic (CFD) dengan konsentrasi alumina 2,5% w/v (0,630% v/v). Model two-phase berdasarkan pendekatan Euler digunakan untuk memprediksi medan temperatur dan aliran. Sedangkan, perhitungan koefisien transfer kalor dilakukan dengan mempertimbangkan temperatur rata-rata yang diperoleh secara numerik dari profil temperatur. Pengaruh konsentrasi nanopartikel dan bilangan Reynolds terhadap bilangan Nusselt diinvestigasi secara numerik sepanjang arah aksial. Hasil menunjukkan bahwa peningkatan signifikan transfer kalor nanofluida yang diobservasi khususnya dalam aliran berkembang pada entrance region yang sesuai dengan korelasi Shah-London. Peningkatan transfer kalor nanofluida Al2O3/EG dengan konsentrasi 2,5% w/v terhadap fluida dasar air dan ethylene glycol pada jarak aksial non dimensional (x/Di = 240) masing-masing sebesar 167,30% dan 6,90%

Laminar Rayleigh–Benard convection in a closed square field with meshless radial basis function method

Research on natural convection is exciting in some experimental and numerical cases, especially in rectangular cavities with relatively low heat dissipation and thermal control systems with low cost, reliability, and ease of use. The present study will use the meshless radial basis function method to solve the velocity formulation of the Navier–Stokes equations by varying some nominal Rayleigh numbers of 104, 105, and 106. The numerical accuracy is compared with the previous research. The advantages of the meshless method are that it does not require a structured mesh and does not require inter-nodal connectivity. The results show that the temperature pattern is identical to the previous research. The calculations have been done for three different Rayleigh numbers of 104, 105, and 106 for 151 × 151 nodes. The variations of the Ra number will affect the isothermal, velocity contours, and Nusselt number

CFD (Computational Fluid Dynamics) Modeling on Narasena Bengawan UV Team Quickster UAV Wings with Addition of Vortex Generator to Aerodynamic Performance

This research is based on obtaining the best possible aerodynamic performance for the Quickster Narasena Bengawan UV Team UAV aircraft wing design. One of the factors that greatly affects the flying performance of a UAV is the wing. The wing on the Quickster Narasena UAV aircraft uses an MH33 airfoil, because MH33 is specifically for high-speed UAV aircraft. This research will discuss the comparison of the performance of a wing without a vortex generator with a wing with a vortex generator. Variations in the positioning of the vortex generator on the wing of the Quickster Narasena UAV will also be discussed in this study. The method used in this research is the CFD (Computational Fluid Dynamics) method. The simulation process will use the ANSYS Fluent 19.0 application with the K-Omega SST method with the Reynolds-Averaged-Navier-Stokes (RANS) equation as the basis. The purpose of this study is to obtain the results of the coefficient of drag, lift, and the contour of the turbulence that will occur. The simulation results that have been done are the geometry of the wing with the addition of a vortex generator can reduce the drag coefficient and can increase the lift coefficient

Magnetically-Induced Pressure Generation in Magnetorheological Fluids under the Influence of Magnetic Fields

This study aims to observe the magnitude of the Magnetorheological Fluids (MRFs) pressure due to the application of a magnetic field. This was accomplished by placing the MRFs in a U-shaped tube, then applying a magnetic field generated by a magnetic coil. A finite element simulation for the magnetic field was carried out to estimate the magnetic field strength generated by the coil variable to the current input given in the simulated apparatus. Changes in MRFs pressure were recorded using a data logger to better observe the fluid pressure phenomena occurring in the MRFs with respect to current input variations. The results showed that the magnetic field influences the MRFs fluid pressure proportionally. The slope is not constant as the magnetic field effect to the fluid pressure gets stronger when the current input is higher. However, there are also an adverse effect of heat generated in the coil in higher current, which results in coil performance degradation and reduces the magnetic field strength

Effect of Water Flow on Underwater Wet Welded A36 Steel

Underwater wet welding (UWW) combined with the shielded metal arc welding (SMAW) method has proven to be an effective way of permanently joining metals that can be performed in water. This research was conducted to determine the effect of water flow rate on the physical and mechanical properties (tensile, hardness, toughness, and bending effect) of underwater welded bead on A36 steel plate. The control variables used were a welding speed of 4 mm/s, a current of 120 A, electrode E7018 with a diameter of 4 mm, and freshwater. The results show that variations in water flow affected defects, microstructure, and mechanical properties of underwater welds. These defects include spatter, porosity, and undercut, which occur in all underwater welding results. The presence of flow and an increased flow rate causes differences in the microstructure, increased porosity on the weld metal, and undercut on the UWW specimen. An increase in water flow rate causes the acicular ferrite microstructure to appear greater, and the heat-affected zone (HAZ) will form finer grains. The best mechanical properties are achieved by welding with the highest flow rate, with a tensile strength of 534.1 MPa, 3.6% elongation, a Vickers microhardness in the HAZ area of 424 HV, and an impact strength of 1.47 J/mm2

The Using of Thermal Energy Storage on Single Slope Solar Still Distiller

Single slope solar still (S4) was the traditional distiller that used solar energy as the primary energy source. The solar energy entering the desalination system is generally large during evaporation. However, productivity tends to lower due to the energy losses that occur during the production period. This research aims to S4 testing with the addition of thermal energy storage (TES) inside the basin. This additional absorber heat could maintain the heat absorption during the production day period. The additional TES is used with the hollow circular fin shaped with the enhanced soybean wax as the phase change material. The study was conducted experimentally from 07.00 to 21.00 GMT +7 by comparing the performance of conventional S4 with additional TEM. The results show that the addition of the TES device influences the S4 performances. Based on the result, the additional TES enhanced the gained performance S4, which was 220 mL and 8.22% higher than conventional S4

The Influence of Water Flow Characteristics on the Physical and Mechanical Qualities of Underwater Wet Welded A36 Marine Steel Plate

Underwater welding has proven to be a successful method of joining two similar or dissimilar metals and takes place underwater. This technique is frequently used for maintenance purposes, such as repairing piping systems, ships, and other marine structures. This study investigates the effect of different water flow types on an underwater weld’s physical and mechanical properties of welded bead on the A36 steel plate. The SMAW method with an E7018 electrode is used for welding A36 steel in saltwater. In this simulation, underwater welding is performed using three types of flow (without flow, non-uniform flow with a baffle plate, and non-uniform flow without a baffle plate) to compare metallography, hardness, tensile, impact, and bending testing results. The findings revealed that the saltwater flow caused more porosity defects. Moreover, the highest penetration depth was observed in specimens with the non-uniform flow with a baffle plate. The heat energy is concentrated due to droplets accumulating in the weld area. The microstructure of welding metals such as acicular ferrite and ferrite with the second phase grows as the water flow becomes non-uniform. Furthermore, as the rate and variability of the water flow increased, the value of the mechanical properties of the specimens increased relatively