Abstract An investigation is conducted into how radiation affects the non-Newtonian second-grade fluid in double-diffusive convection over a stretching sheet. When fluid is flowing through a porous material, the Lorentz force and viscous dissipation are also taken into account. The flow equations are coupled partial differential equations that can be solved by MATLAB’s built-in bvp4c algorithm after being transformed into ODEs using appropriate similarity transformations. Utilizing graphs and tables, the impact of a flow parameter on a fluid is displayed. On velocity, temperature, and concentration profiles, the effects of the magnetic field, Eckert number, and Schmidt number have been visually represented. Calculate their inaccuracy by comparing the Nusselt number and Sherwood number values to those from earlier investigations.

Abstract The scarcity of the insulators that are required for refrigeration has made it necessary to use locally available materials that can achieve the desired refrigeration. This work presents the performance evaluation of a refrigerator utilizing a locally available material, which is wood particles that have been converted to particle board, as one of its insulators. A vapor compression refrigeration system was designed and fabricated to chill and preserve agricultural products, which are eggs, yogurt, and tomatoes. The various temperatures at which the agricultural products became chilled were compared with their theoretical preservation temperatures obtainable in literature, thereby evaluating the performance of the refrigerator. The temperature of 11 ℃, which was recorded for the egg in the present experiment, is lower than the theoretical preservation temperatures of 18 ℃ to 21 ℃ for an egg. The temperature of 7 ℃, which was recorded for the yogurt, is approximately equal to its theoretical preservation temperature of 5 ℃. The temperature of 8 ℃, which was recorded for the tomato, is lower than the theoretical preservation temperatures of 7 ℃ to 10 ℃ of tomato. This work has revealed that wood particles have the potential to achieve refrigeration, as well as chill and preserve agricultural products.

Abstract The Organic Rankine Cycle (ORC) is an electricity generation system that uses organic fluid instead of water in the low temperature range. The Organic Rankine cycle using zeotropic working fluids has wide application potential. In this study, data mining (DM) model is used for performance analysis of organic Rankine cycle (ORC) using zeotropik working fluids R417A and R422D. Various DM models, including Linear Regression (LR), Multi-Layer Perceptron (MLP), M5 Rules, M5 Model Tree, Random Committee (RC), and Decision Tree (DT) models are used. The MLP model emerged as the most effective approach for predicting the thermal efficiency of both R417A and R422D. The MLP’s predicted results closely matched the actual results obtained from the thermodynamic model using Genetron software. The Root Mean Square Error (RMSE) for the thermal efficiency was exceptionally low, at 0.0002 for R417A and 0.0003 for R422D. Additionally, the R -squared ( R 2 ) values for thermal efficiency were very high, reaching 0.9999 for R417A and R422D. The findings demonstrate the effectiveness of the DM model for complex tasks like estimating ORC thermal efficiency. This approach empowers engineers with the ability to predict thermal efficiency in organic Rankine systems with high accuracy, speed, and ease.

Abstract The gravure printing process is widely utilized for large-scale, high-quality, multi-colored printing tasks executed at high press speeds. This includes a diverse range of products such as art books, greeting cards, currency, stamps, wallpaper, magazines, and more. This thesis addresses the fire risks associated with gravure printing, acknowledging the use of highly flammable materials and the potential for static charge-related incidents. Despite its prevalence, there is limited research on fire prevention and control in gravure printing. The study employs field observations, stakeholder interviews, and an extensive review of literature on fire risk and control in printing press operations in India. It analyzes the causes of fires using the fire triangle model, emphasizing the role of heat, combustible materials, and oxygen in fire incidents within the printing press environment. The thesis categorizes preventive measures into fire prevention and fire suppression actions, focusing on reducing fire load, static charge mitigation, and implementing firefighting systems. It observes that poor housekeeping, lack of awareness, and inadequate emergency control plans contribute significantly to fire hazards in press facilities. Additionally, the research identifies key factors such as high press temperatures, low humidity, improper storage, and inadequacies in firefighting systems as potential causes of fires. It emphasizes the need for optimal environmental conditions, proper storage practices, and effective firefighting infrastructure within press facilities. The study concludes with comprehensive guidelines for loss prevention and control, including management programs, housekeeping, operator training, pre-emergency planning, preventive maintenance, and plant security. It also addresses safety measures specific to gravure printing presses, such as automatic sprinkler systems, fire hydrant system, carbon dioxide flooding systems, and portable fire extinguishers. In summary, this thesis provides valuable insights into the multifaceted nature of fire risks in gravure printing presses and recommends a holistic approach for effective fire prevention and control.

Abstract In this paper, a solar tracking device that can continuously track the sun by adjusting the direction and angle of the solar panel in real time is designed and fabricated to improve the power generation efficiency of the solar cell panel. The mechanical parts as well as the automatic control part of the passive sun-tracking system are described, and the efficiency enhancement with the sun-tracking solar panel is characterized in comparison with the fixed panel system. The test results show that in the spring season in Qingdao city of eastern China, the sun-tracking system can improve the solar cell power generation efficiency by 28.5%–42.9% when comparing to the direction and elevation angle fixed system in sunny days. Even in partly cloudy days, the PV power output can increased by 37% with using the passive sun-tracking system. Economic analysis results show the cost-benefit period is about 10 years, which indicates that the passive sun tracking device can substantially contribute to the solar energy harvest practices.

Abstract Carbon based materials are really an integral component of our lives and widespread research regarding their properties was conducted along this process. The addition of dopants to carbon materials, either during the production process or later on, has been actively investigated by researchers all over the world who are looking into how doping can enhance the performance of materials and how to overcome the current difficulties. This study explores synthesis methods for nitrogen-doped carbon materials, focusing on advancements in adsorption of different pollutants like CO 2 from air and organic, inorganic and ions pollutants from water, energy conversion, and storage, offering novel solutions to environmental and energy challenges. It addresses current issues with nitrogen-doped carbon materials, aiming to contribute to sustainable solutions in environmental and energy sciences. Alongside precursor types and synthesis methods, a significant relationship exists between nitrogen content percentage and adsorption capacity in nitrogen-doped activated carbon. Nitrogen content ranges from 0.64% to 11.23%, correlating with adsorption capacities from 0.05 mmol/g to 7.9 mmol/g. Moreover, an electrochemical correlation is observed between nitrogen atom increase and specific capacity in nitrogen-doped activated carbon electrodes. Higher nitrogen percentage corresponds to increased specific capacity and capacity retention. This comprehensive analysis sheds light on the potential of nitrogen-doped carbon materials and highlights their significance in addressing critical environmental and energy challenges.