Current Issue : July-September Volume : 2025 Issue Number : 3 Articles : 5 Articles
The projected population of Indonesia to reach of around 320 million people in 2045 is worried to threaten the growth of various plants. The threat occurs due to various human activities that result in reduced land for growing plants and climate change. Plants are needed by humans as a source of food, medicine, and other valuable products. Plant Factory (PF) is a place for indoor plant production with climatic conditions that can be adjusted according to needs and is used as an effort to increase plant production on limited land. The Mini Plant Factory (MPF) is a small-scale of PF. This study concerns to simulate the MPF model in order to understand better the distribution of air temperature and velocity in it. Computational Fluid Dynamics (CFD)-based simulations were carried out in the bright period (plants carry out photosynthesis) and dark period (plants carry out transpiration). Transient simulations conducted to determine the duration of the AC compressor turns on and off in a day operation. The duration is used to calculate the operating costs of the MPF. The investment costs and income are also calculated to estimate the payback period of MPF. The air temperature around the planting rack is kept close to 21°C in the bright period and 19°C in the dark period. Within 24 hours, the AC compressor is on for 9.2 hours and off for 14.8 hours. The investment cost incurred to make MPF on an existing building is IDR 22,961,471.00. MPF can generate income of IDR 11,673,851.00 annually. The payback period of MPF project in this study was around two years....
This study presents a numerical methodology for analyzing hydroacoustic noise generation and its propagation in a homogeneous domain using Lighthill’s analogy, the finite volume method, and hybrid-Higdon boundary conditions. The approach consists of three key steps: performing an eddy-resolving Large Eddy Simulation to capture the unsteady fluid dynamics, extracting the turbulent field to compute the acoustic source term via Lighthill’s analogy, and solving a homogeneous wave equation to propagate the noise in an open domain. The methodology is applied to a turbulent plane channel flow, simulating the acoustic field for a fluid with water-like density at a Mach number of 0.1. The results reveal the spatial distribution of the acoustic pressure, highlighting the dominant noise sources and their spectral characteristics. The acoustic domain extends beyond the turbulent region, enabling the study of pressure propagation outside the flow. The findings demonstrate that noise generation is strongly linked to turbulent structures near the walls, with significant acoustic radiation occurring in the low-wavenumber range. This framework provides a powerful tool for modeling noise propagation in marine and industrial applications, offering insights into turbulence-induced sound in underwater environments. Future work could extend the approach to more complex geometries, higher Reynolds numbers, and heterogeneous domains, further advancing its applicability to real-world acoustic challenges....
The Li-ion battery is electrical storage in the form of chemical energy and is considered the strongest candidate for electrical-based automotive applications. The performance of the battery greatly affects the performance of electric vehicles. There is a need for effective thermal management to control battery temperature below a defined temperature such as 50°C. The thermal management system in the battery can be done by passively cooling it using heat pipes and heat sinks. This research was conducted by simulating the Makara Electric Vehicle's electric scooter battery module which was applied with a heat pipe-based cooling system. The simulated module focuses on heat pipes and 18650 lithium-ion batteries with discharge rate variations of 1C, 2C., and 3C. The method used is literature study and CFD simulation. The results show that the heat pipe cooling system can reduce battery temperature at each discharge rate variation of 12,85%, 16,23%, and 23,74%. Heat Pipe can absorb the highest heat of 68,1178 kW when the module uses a 3C battery....
On 28 March 2005, a major Mw 8.6 earthquake occurred near Nias and Simeulueislands, in the vicinity of northwestern Sumatra (Indonesia). The earthquake generated a significant tsunami. Although it was not as destructive as the 2004 Sumatra tsunami, the 2005 event was of sufficient strength to be recorded by tide gauges throughout the entire Indian Ocean. We selected 12 records for analysis, most from open-ocean islands but also some from continental stations. The maximum wave heights were measured at Salalah (Oman) (87 cm), Colombo (Sri Lanka), Pointe La Rue (Seychelles) and Rodrigues Island (53–54 cm). The dominant wave periods, estimated from frequency–time (f-t) diagrams, were 60–66 min, 40–48 min, and 20 min, which we assume are associated with the 2005 tsunami source. From the same stations, we calculated the mean ratio of the 2004 to 2005 tsunami heights as 5.11 ± 0.60, with the maximum and minimum heights to the west and south of the source region as 9.0 and 2.49, respectively. We also used these data to estimate the mean energy index, E0 = 65 cm2, for the 2005 tsunami, which was 16 times smaller than for the 2004 event. The USGS seismic solution was used to construct a numerical model of the 2005 tsunami and to simulate the tsunami waveforms for all 12 tide gauge stations. The results of the numerical computations were in general agreement with the observations and enabled us to map the spatial wave field of the event. To estimate the influence of location and orientation of the source area on the propagating tsunami waves, we undertook a set of additional numerical experiments and found that this influence is substantial and that these factors explain some of the differences between the physical properties of the 2004 and 2005 events....
High-purity germanium (HPGe) detectors occupy a prominent position in fields such as radiation detection and aerospace because of their excellent energy resolution and wide detection range. To achieve a broader detection range, conventional HPGe detectors often need to be expanded to cubic-centimeter-scale volumes. However, this increase in volume leads to a large detector area, which in turn increases the detector capacitance, affecting the detector’s noise level and performance. To address this issue, this study proposes a novel high-purity germanium drift detector (HPGeDD). The design features a small-area central collecting cathode surrounded by concentric anode rings, with a resistive chain interposed between the anode rings to achieve self-dividing voltage. This design ensures that the detector’s capacitance is only related to the area of the central collecting cathode, independent of the overall active area, thus achieving a balance between a small capacitance and large active area. Electrical performance simulations of the novel detector were conducted using the semiconductor simulation software Sentaurus TCAD (P-2019.03). The results show a smooth electric potential distribution within the detector, forming a lateral electric field, as well as a lateral hole drift channel precisely directed toward the collecting cathode. Furthermore, simulations of heavy ion incidence were performed to investigate the detector’s carrier collection characteristics. The simulation results demonstrate that the HPGeDD exhibits advantages such as fast signal response and short collection time. The design proposal presented in this study offers a new solution to the problem of excessive capacitance in conventional HPGe detectors, expands their application scope, and provides theoretical guidance for subsequent improvements, optimizations, and practical manufacturing....
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