ABSTRACT
A solar cell is a converter that uses semiconductor material to convert photon energy packets. The electrons located in the material's crystalline structure can escape from the bonds between their atoms and generate electricity. Photovoltaic (PV) solar cells can work via diffuse radiation and have the highest efficiency among other types of solar cell generation. Photovoltaic Thermal Collector (PVT)-based active cooling technology makes it possible to increase the efficiency of PV solar cells and to generate thermal energy at the same time through the direct conversion of solar radiation. Therefore, this study modeled various riser configurations on PVT collectors to cool PV solar cells using water heat transfer fluids and nanofluids: TiO2, SiO2, and Al2O3. The mass flow rates were varied. An ANSYS models a simulation of the heat transfer phenomenon between the PV cell layer and the fluid. Only the heat transfer phenomenon generated from the natural convection of the PV cell layer is studied using steady-state thermal ANSYS with simulated controlled conditions. The radiation intensity of 1000 W/m2 has the photovoltaic solar cells with the most negligible efficiency. The semicircular collector configuration with water at a mass flow rate of 0.5 kg/s demonstrated the highest electrical efficiency, achieving 11.98%.
ABSTRACT
Two of the most hazardous benzene derivatives (HBD) that have polluted the aquatic environment are bromobenzene and chlorobenzene. Ferrate can degrade various pollutants quickly and efficiently without producing harmful byproducts. This study aims to determine the ability of ferrate to degrade harmful contaminants such as bromobenzene and chlorobenzene. A series of batch experiments were carried out, including for the molar ratio, initial pH solution, and temperature. The study was conducted at an initial pH of 3.6 to 9.6, a molar ratio of 2 to 8 and a temperature of 15 to 55 °C. The study will also examine the differences in functional groups in these pollutants. As a result of the experiments, the optimum conditions to oxidize HBD in a batch reactor was found to have an initial pH of 7.0, a molar ratio of 8, and a temperature of 45 °C, with a 10 min reaction time. Ferrate has a degradation ability against chlorobenzene greater than bromobenzene. The functional cluster in pollutants also significantly affects the degradation ability of ferrate. The results of the degradation experiment showed that ferrate(VI) could effectively oxidize hazardous benzene derivatives in a solution.
ABSTRACT
Aluminium matrix composites (AMCs) are widely used in various applications because of their excellent properties; however, their lightweightness limits their broad application scope. Various ceramic compounds are used as reinforcements in AMCs, such as Al2O3, SiC, ZrO2, and TiO2. However, the use of ceramic compounds results in high production costs in AMC manufacturing. Thus, the substitution of reinforcement particles with various organic and industrial waste reinforcements is required. In line with the research trend of using industrial waste materials such as rice husk ash, red mud, and fly ash, this study uses sea sand as an AMC reinforcement. Sea sand is used because it primarily contains SiO2 and Fe3O4 ceramic compounds and, thus, can be used as a reinforcement. This study aims to determine the physical and mechanical properties of an AA6061-sea sand composite. Sea sand was subjected to electroless coating to increase its wettability before the stir-casting process. The as-prepared composite was manufactured by the stir-casting method upon the addition of 2-6 wt% sea sand. Composite characterisation was carried out through Brinell hardness and tensile tests. The results showed that the electroless-coated composites possessed lower porosity and, therefore, higher hardness and ultimate tensile strength than the non-electroless-coated composites.
ABSTRACT
The safety of ships in regards to collisions and groundings, as well as the navigational and structural aspects of ships, has been improved and developed up to this day by technical, administrative and nautical parties. The damage resulting from collisions could be reduced through several techniques such as designing appropriate hull structures, ensuring tightness of cargo tanks as well as observation and review on structural behaviors, whilst accounting for all involved parameters. The position during a collision can be influenced by the collisions' location and angle as these parts are included in the external dynamics of ship collisions. In this paper, the results of several collision analyses using the finite element method were used and reviewed regarding the effect of location and angle on energy characteristic. Firstly, the capabilities of the structure and its ability to resist destruction in a collision process were presented and comparisons were made to other collision cases. Three types of collisions were identified based on the relative location of contact points to each other. From the results, it was found that the estimation of internal energy by the damaged ships differed in range from 12%-24%. In the second stage, the results showed that a collision between 30 to 60 degrees produced higher level energy than a collision in the perpendicular position. Furthermore, it was concluded that striking and struck objects in collision contributed to energy and damage shape.
