Papers by Keyword: Efficiency

Abstract: The aim of this research is to determine the thermal insulation efficiency of cashew nut shell (CNS) ash with a mixture of 1:0.25 (tile nut am-53) and 1:0.25 (tile nut am-53):0.25 (sago). The method used in this research is the experimental method. Research resaeach Heater element capacity is 396 W/m².°C, resulting in a thermal conductivity of 0.89 watts/m.°C and 106.58 Watt for conduction heat for sample I; and thermal conductivity 0.150 watts/m.°C and 92.16 Watt for conduction heat for sample II. Where the material in Sample I (mixture of cashew shell ash, Tile Grout AM53, and sago with a composition of 1: 0.5: 0.5) is able to insulate heat by 73% and Sample II (mixture of cashew shell ash, Tile Grout AM53, and sago with a composition of 1:0.5:1) by 76.72%.

Abstract: Universities are significant energy consumers, and effective energy management is important for sustainability and cost reduction. This article explores the role of energy audits in helping universities improve their energy management and sustainability practices. It analyzes research from 2010 to 2024 to identify various energy auditing techniques, tools, and methodologies used by different institutions. The article demonstrates how diverse auditing approaches can uncover energy inefficiencies and propose practical solutions. Key findings indicate that thorough energy audits are important for promoting sustainability goals through improved energy efficiency and waste reduction. However, universities face challenges in implementing audit recommendations due to infrastructure limitations and technological constraints. The review emphasizes the essential role of energy auditing in enhancing both environmental and economic performance and underscores the importance of ongoing innovation and adaptation in energy auditing practices. In conclusion, the article suggests exploring new technologies and improving auditing techniques to better support sustainability efforts in universities.

Abstract: Consuming halal products has become part of today's lifestyle. In addition, product halal assurance is one of the basic requirements for Indonesian products to penetrate the global halal market. The government continues to encourage the existence of a new Halal Inspection Agency as a form of strengthening halal product guarantees as well as accelerating the development of the halal industry in Indonesia. The purpose of this study is to evaluate the efficiency of performance in each product group segment at one of the Halal Inspection Agency using Data Envelopment Analysis. Performed for 9 segments of the main product groups using input and output variables. The input variables are what non-profit organizations used to produce output such as the number of employees, while the output variables are a measurement of the output provided by the organizations. The finding shows that of 9 product segments, 2 were identified as being efficient and others are still inefficient. By using the CCR model, this study proposed the cause of inefficiency. This research also provides slack and radial movement analysis. The methods and the results of this study can serve as a model for researchers and practitioners to follow when evaluating efficiency in non-profit organizations.

Abstract: This paper presents a numerical simulation of a dual-junction tandem GaInp/GaAs cell made from top GaInp and bottom GaAs cells. For this purpose, we utilized a numerical simulation tool. Two methodologies were proposed, the first method consists of simulating each base layer cell of the top and bottom separately, and the second method simulated both layers in one file, to simulate both in one file. For improved electric characteristics of tandem solar cells, the current-match requirement between the top and bottom cells should be satisfied, necessitating the careful design of parameters. The top base GaInp layer thickness is adjusted to match this requirement. The solar spectrum reaching the lower cell is analytically calculated by subtracting the top cell spectrum from the total spectrum. the optimal value of short current density corresponds with a top cell base thickness of 0.8 µm, this results in an open circuit voltage of 2.45 V, a short circuit current of 15.7 Am/cm², a fill factor of 91 %, an efficiency of 35 % for the first method and the second method used a script file designed to verify the above results and confirmed the values to be; 2.68 V open circuit voltage, 15.26 Am/cm², a short circuit current, 90 % fill factor, and 36.86 % efficiency under AM 1.5 G solar spectrum.

Abstract: This study presents an investigation on Earth-Air Heat Exchangers (EAHEs), a sustainable and cost-effective alternative for improving thermal conditions in environments. The EAHE consists of one or more ducts buried at a certain depth, and a ventilation system, which allows air to flow through the ducts and exchange heat with the soil. The soil, being warmer than the ambient air during cold periods and cooler during hot periods, facilitates this heat exchange. The research aims to evaluate and compare the potential of the soil and EAHE in a system where a galvanized material, shaped like an ellipse, is attached around the duct. Given the high thermal conductivity of galvanization, this material helps enhance the thermal potential of the soil. Two tests were conducted by altering the horizontal and vertical dimensions of the ellipse while keeping the area constant. The results obtained with the galvanized structure were compared with those obtained without the use of this material. Moreover, the authors compared two different geometries of the structures: a circular one, which had been previously tested, and an ellipsoidal one. Additionally, the thermal potentials of the soil and the system improved as the horizontal length of the ellipse decreased.

Abstract: Carbide machining process brings a whole range of problems in practice. This mainly concerns problems associated with their machinability and the economy of the applied machining technology. Because of these problems, it is often not possible to use traditional production technologies when machining them. However, progressive machining technologies achieve relatively good results. However, even with progressive technologies, the problem with the overall efficiency of the machining process remains. Therefore, experimental research was carried out, the aim of which was to obtain relevant data regarding the quantification of qualitative indicators of the machined surface during the machining of hard metals through progressive electrical discharge technology in relation to the overall economic efficiency of the machining process. As part of the conducted experimental research, partial data of individual elements were obtained on the basis of which complex conclusions were drawn in mutual contexts. Subsequently, complex data regarding the effectiveness of the applied electrical discharge process in the machining of hard metals were summarized.

Abstract: In this paper, we examined CH₃NH₃PbI₃ potential as an absorber component for perovskite solar cells (PSCs). We used CuSCN (copper thiocyanate) as the hole transport layer and, ZnO as the electron transport layer to optimize work the device, in the CH₃NH₃PbI₃-based perovskite solar cell, and we used the solar cell capacitance simulator (SCAPS-1D). Exemplary perovskite solar cell is made up of six main layers, each of which is composed of a different material: glass, a thinning layer of fluorine-doped tin oxide substrate (FTO), ZnO for electron transport, CH₃NH₃PbI₃ for methylammonium lead iodide for the perovskite effective layer, copper thiocyanate for hole transport, and platinum (Pt) for the electrode. The best Optimized device structure, FTO / CuCSN /CH₃NH₃PbI₃ / ZnO /Pt, had a power conversion efficiency of 42.69%, according to simulation data. We examined the impact of changing thickness, defect density, and temperature on the efficiency of the device. The Optimum efficiency we get at thickness 10 μm is 42.69%, which is a promising result, Jsc is 29.766433 (mA/cm²), and FF is 91.39% and Voc is 1.5692 (V), best efficiency corresponds to defect density 1*. while, we note that the efficiency of perovskite solar cells decreases gradually at increase temperature.

Abstract: Researchers continue to be concerned about corrosion of materials, which motivates them to start projects to address the harmful impacts of this phenomena that affects the desired function of our materials, especially in industries where acid is used in the process of cleaning machines. The purpose of this study is to reduce the corrosion rate of brass in 5M solution of H₂SO₄ acid using orange juice as inhibitor. The study was conducted using weight loss method. It was observed that for 24 hours the corrosion rate was higher for acid and decreased as the inhibitor was added. In all samples the corrosion rate decreases as the inhibitor were added, however improves over time. For 24 hours the efficiency was higher for acid + 100mil at 14% and it became constant after 48hrs at 32,7%. However, for 72 – 96 hours acid + inhibitor of 60mil there efficiency reported to be 54.3 and 56.4%. Keywords-orange juice, inhibitor, corrosion, acid, efficiency.

Abstract: The performance indicators of the functioning wireless cellular networks when using Wi-Fi & WiMAX systems are analyzed, taking into account modern energy-saving technologies. The Wi-Fi & Wi-MAX standards technologies have been studied, and a number energy saving mechanisms are being studied. The main idea is considered, which is to periodically turn off the radio-transmitting interface and the modem server to save energy while listening to the communication channel.

Abstract: The effectiveness various algorithms for the operation energy-saving mechanisms mobile cellular networks is analyzed. Modern scenarios energy saving in Wi-Fi networks are considered, in terms power consumption and delayed delivery frame streams for energy-saving stations. The effectiveness energy saving mechanisms in mobile cellular networks when using Wi-Fi radio interface is studied and analytical expressions for estimating power consumption are obtained.