Thermal Science最新文献_第9页

On the solution of lake pollution model by Sinc collocation method 湖泊污染模型的Sinc配点法求解

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2304385y

Turgut Yeloglu

引用次数: 0

Riemannian submersions endowed with a new type of semi-symmetric non-metric connection 黎曼淹没被赋予了一种新的半对称非度量连接

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2304393k

Esra Karatas, Semra Zeren, Mustafa Altin

引用次数: 0

Experimental optimization of tribological properties of aluminum bronze alloys made by the forging method 锻压法制备铝青铜合金摩擦学性能的实验优化

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2304101c

Idris Cesur, Aslan Coban, Sefa Bacak, Ibrahim Ozsert, Omer Secgin, Akin Kapti

{"title":"Experimental optimization of tribological properties of aluminum bronze alloys made by the forging method","authors":"Idris Cesur, Aslan Coban, Sefa Bacak, Ibrahim Ozsert, Omer Secgin, Akin Kapti","doi":"10.2298/tsci2304101c","DOIUrl":"https://doi.org/10.2298/tsci2304101c","url":null,"abstract":"Aluminum bronze alloys produced by various methods are preferred materials in many fields of the industry due to their high wear resistance and good sliding properties. This study investigated the tribological properties of aluminum bronze alloys produced by forging from Cu, Al, Fe, and Mg elements. Dry sliding wear tests were carried out on a pin-on-disc wear device. Three tribological properties, wear, friction coefficient, and temperature of aluminum bronze alloys were investigated. Experimental studies were carried out for different loads, sliding speeds, and sliding ways. The factorial experiment design method was applied in the MINITprogram. A SEM visualized the samples microstructures to examine the material wear characteristics. As a result of the study, it was deter-mined that the applied load, sliding speed, and sliding way were effective parameters on the amount of wear and friction coefficient. The maximum amount of wear was 0.352 mg at 100 N load, 3 m/s sliding speed, and 3000 m sliding way conditions. The maximum temperature between materials under these conditions is 299 oC. The minimum amount of wear was obtained when 25 N load, 1 m/s sliding speed, and 1000 m sliding way were applied.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135440987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Improvement of the performance of small-sized cavitating venturis by inserting obstacles 通过插入障碍物改善小型空化风投的性能

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2304467r

Brahim Rostane, Khaled Aliane, Mohammed Brayyich, Sajad Zearah, Ali Akgul, Barno Abdullaeva, Younes Menni, Abdulrhman Alsharari, Jihad Asad

{"title":"Improvement of the performance of small-sized cavitating venturis by inserting obstacles","authors":"Brahim Rostane, Khaled Aliane, Mohammed Brayyich, Sajad Zearah, Ali Akgul, Barno Abdullaeva, Younes Menni, Abdulrhman Alsharari, Jihad Asad","doi":"10.2298/tsci2304467r","DOIUrl":"https://doi.org/10.2298/tsci2304467r","url":null,"abstract":"Cavitating Venturis are simple apparatus used as a flow meter over a broad range of mass-flow rates. The main objective of this work is to introduce obstacles in small-sized cavitating Venturis in order to increase their capacity by raising the critical pressure, i.e. widens the phase of the cavitating mode. Four configurations have been tested depending on the location of these obstacles. This study focused on investigating the numerical performance of cavitating Venturis with different downstream pressures by employing the k-? SST turbulence model and the Rayleigh-Plesset equation for modeling cavitation. The governing equations were solved using the finite volume method, employing the Rhie and Chow pressure-velocity coupling scheme. The results showed the void fraction and streamlines contours obtained on the symmetry plane. The mass-flow ratio was presented for all configurations and different pressure ratios. The study showed that the cavitating Venturis equipped with obstacles extend the phase of choked mode from 10.71% to 21.42% and that the best configuration correspond to the case where the obstacles are placed in the converging section.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135441012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Artificial neural network based prediction of engine-out responses from a biodiesel fuelled compression ignition engine 基于人工神经网络的生物柴油压缩点火发动机熄火响应预测

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2304433k

Cheikh Kezrane, Houcine Habib, Mustafa Bayram, Sultan Alqahtani, Sultan Alshehery, Omolayo Ikumapayi, Esther Akinlabi, Stephen Akinlabi, Khaled Loubar, Younes Menni

{"title":"Artificial neural network based prediction of engine-out responses from a biodiesel fuelled compression ignition engine","authors":"Cheikh Kezrane, Houcine Habib, Mustafa Bayram, Sultan Alqahtani, Sultan Alshehery, Omolayo Ikumapayi, Esther Akinlabi, Stephen Akinlabi, Khaled Loubar, Younes Menni","doi":"10.2298/tsci2304433k","DOIUrl":"https://doi.org/10.2298/tsci2304433k","url":null,"abstract":"Numerical simulations, based on relatively complex physical models developed for CFD, can accurately predict engine-out responses, but they require huge memory space and/or computation time. In terms of resources and computer time, artificial intelligence methodologies are more cost-effective. In this work, we used an ANN to predict the performance and exhaust emissions of a single-cylinder Diesel engine running on fossil diesel, biodiesel, and their blends under various speed and load regimes. To perform the modeling, we employed multilayer perceptrons and a back-propagation gradient algorithm with momentum to train the network weights. The modification of the network weights was done using the second-order method of Levenberg-Marquardt, and the technique of early termination was utilized to avoid overtraining the model. The study involved using 70% of the complete experimental data to train the neural network, allocating 15% for network validation, and reserving the remaining 15% to evaluate the trained network effectiveness. The ANN model that was created demonstrated remarkable accuracy in predicting both engine performance and emissions. This is evident from the strong correlation coefficients observed, which ranged from 0.987 to 0.999, as well as the low mean squared errors ranging from 7.44?10-4 to 2.49?10-3.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"2013 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135441526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Engine performance and emission characteristics of microwave-produced biodiesel blends 微波生产生物柴油混合物的发动机性能和排放特性

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci230603205h

Fakher Hamdi, Ilhem Yahya, Mehrez Gassoumi, Aliya Fazal, Ridha Ennetta, Serhad Soyhan

{"title":"Engine performance and emission characteristics of microwave-produced biodiesel blends","authors":"Fakher Hamdi, Ilhem Yahya, Mehrez Gassoumi, Aliya Fazal, Ridha Ennetta, Serhad Soyhan","doi":"10.2298/tsci230603205h","DOIUrl":"https://doi.org/10.2298/tsci230603205h","url":null,"abstract":"The main objective of this research is to investigate, experimentally, the effects of biodiesel blends on the performance and emissions of a diesel engine. Measurements were carried out on a single-cylinder, four-stroke, and air-cooled compression-ignition engine, under half and full load conditions. Engine speed was varied from 1000 to 3000 rpm. Biodiesel was produced by transesterification process of sunflower oil with ethanol, using microwave-assisted heating reactor. Three biodiesel-diesel mixtures: containing 5%, 10% and 20% by volume of biodiesel, respectively, have been tested and compared to pure diesel fuel. The effects of these biodiesel blends on the engine operating characteristics such as brake specific fuel consumption, brake power, brake thermal efficiency, brake mean effective pressure and on carbon monoxide, carbon dioxide and nitrogen oxides emissions, have been investigated. It was noticed that, at full load, the specific fuel consumptions of biodiesel blends were higher compared to the pure diesel fuel, but no change was observed under 1/2 load. An improvement in the brake thermal efficiency, under 1/2 load, was obtained, but at full load, for medium and high-speed, the thermal efficiencies of all biodiesel blends showed a decrease compared to pure diesel fuel. Concerning pollutants emissions, a decrease in carbon monoxide emissions of all biodiesel blends was noticed. The best result in carbon monoxide emissions was achieved by the mixture containing 10% by volume of biodiesel with an average reduction value close to 40%. In addition, a significant reduction in nitrogen oxides emissions was observed for the three biodiesel blends.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136002729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of process parameters of refrigeration process for a refrigerant mixture 混合制冷剂制冷工艺参数的优化

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci221005220k

Ganapathi Karthik, Alagesan Parthiban, Radha Krishnan, Sivasankaran Thangarajan Senthilkumar

引用次数: 0

Enhancing sustainability and performance of automated air conditioners through optimizing product recovery in closed-loop supply chains 通过优化闭环供应链中的产品回收，提高自动化空调的可持续性和性能

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220907221p

Sivaraman Parthasarathi, Santhosh Srinivasan

{"title":"Enhancing sustainability and performance of automated air conditioners through optimizing product recovery in closed-loop supply chains","authors":"Sivaraman Parthasarathi, Santhosh Srinivasan","doi":"10.2298/tsci220907221p","DOIUrl":"https://doi.org/10.2298/tsci220907221p","url":null,"abstract":"This article investigates the use of closed-loop supply chains (CLSC) to improve the sustainability and performance of automatic air conditioning systems. With the growing use of automated air conditioning systems in automobiles, it is necessary to analyze and optimize their efficiency even after their life span. To reliably anticipate the performance of automatic air conditioning systems, the suggested method employs a unique soft computing technology based on support vector machines (SVM). Furthermore, the research focuses on the deployment of CLSC, which allows for optimal product recovery and resource utilization. To optimize the multi-product, multi-time, multi-echelon network, a generalized CLSC model is built, considering costs, product recovery possibilities, unknown parameters, and environmental performance. The study sheds light on reverse logistics decision-making, such as centre placement and allocation, as well as cultivation of supplier relationships. Overall, this study's incorporation of CLSC and the SVM-based performance prediction approach supports sustainable manufacturing practices. It emphasizes the significance of resource efficiency, waste minimization, and environmental effect mitigation in air conditioning system design, manufacture, and operation. Manufacturers may increase not just their environmental sustainability but also the performance and durability of their air conditioning systems by optimizing product recovery and utilizing closed-loop supply chains. This study provides industry stakeholders with practical information, supporting the adoption of sustainable practices and contributing to a more sustainable and efficient manufacturing ecosystem.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136002742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of lockdown on air quality in Belgrade during COVID-19 pandemic COVID-19大流行期间封锁对贝尔格莱德空气质量的影响

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci230706212v

Biljana Vucicevic, Marija Zivkovic, Valentina Turanjanin, Vukman Bakic, Marina Jovanovic

{"title":"Impact of lockdown on air quality in Belgrade during COVID-19 pandemic","authors":"Biljana Vucicevic, Marija Zivkovic, Valentina Turanjanin, Vukman Bakic, Marina Jovanovic","doi":"10.2298/tsci230706212v","DOIUrl":"https://doi.org/10.2298/tsci230706212v","url":null,"abstract":"The Environmental Protection Agency of the Republic of Serbia continuously monitors and collects air quality parameters at numerous measuring points throughout the country. The results revealed that the levels of air pollution recorded during the lockdown differed from those recorded during the same period the previous years. In this paper, we examined pollutant concentration trends in 2020 and a few previous years to determine the underlying causes of these trends. Pollutants are measured at five stations in Belgrade from the beginning of March to the end of July between 2015 and 2020. Because no hourly data were available, nitrogen dioxide, sulphur dioxide, and suspended particles PM10 and PM2.5 are average daily values, whereas carbon monoxide and ozone are daily 8-hour maximums. Concentrations were compared and averaged only when data for the same period over time was available, i.e. when comparing 2020 to previous years. The results were compared to the annual and daily limit values (for ozone and carbon monoxide 8h maximums, respectively), as well as the variations in concentrations over time. The goal of calculating and displaying these values is to specifically identify a change in air pollution during the COVID-19 virus pandemic isolation period. In general, for Belgrade in 2020, NO2 concentrations are lower at four stations; PM2.5 concentrations are lower at two stations; PM10 concentrations are higher at one station and lower at another; and SO2 concentrations are higher than in previous years (2015-2019).","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136002752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigations on a novel composite phase change material comprising paraffin wax and CQDs for thermal conductivity enhancement 石蜡与CQDs复合相变材料增强导热性能的研究

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220911217j

Emeema Janumala, Murali Govindarajan, Venkateswara Reddi Bomma, Sivakandhan Chinnasamy

引用次数: 0