Thermal Science最新文献_第4页

Preparation and properties of silicate inorganic external wall insulation materials based on heat storage 基于蓄热的硅酸盐无机外墙保温材料的制备及性能研究

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2302941l

Qing Li, Hao Chen, Zhidong Li

{"title":"Preparation and properties of silicate inorganic external wall insulation materials based on heat storage","authors":"Qing Li, Hao Chen, Zhidong Li","doi":"10.2298/tsci2302941l","DOIUrl":"https://doi.org/10.2298/tsci2302941l","url":null,"abstract":"In this article, the foaming slurry after the reaction of silicate inorganic gelling material sodium silicate and foaming agent azodicamide is taken as the main investigation object, and the mechanism of bubble nucleation and the effect of physical parameters such as temperature, time, viscosity and surface tension on the structure of bubble pores are analyzed. As well as the influence of processing technology such as foiling temperature, heating rate, holding time and various kinds of modifiers on the structure and properties of the material, the appropriate processing technology conditions and modifiers are screened out, and an inorganic foiling insulation material with light weight, high strength, heat preservation, fire prevention, no pollution, low cost, simple process and easy to use is prepared. The experimental results show that, although the properties of the prepared material are better with the increase of azodicarbonamide (ADC) content and viscosity, the maximum amount of ADC added is only 1%. When the ADC content in the system is greater than 1%, the foaming slurry will appear gel, which is not conducive to the late high temperature foaming and the uniformity of the final product. Therefore, the optimal amount of ADC is 1% of the mass of sodium silicate.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"63 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68260759","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

Does agricultural productive service promote agro-ecological efficiency? Evidence from China 农业生产性服务促进农业生态效率吗?来自中国的证据

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2303109l

Wang Tang, Faming Zhou, Liulin Peng, Mingzheng Xiao

{"title":"Does agricultural productive service promote agro-ecological efficiency? Evidence from China","authors":"Wang Tang, Faming Zhou, Liulin Peng, Mingzheng Xiao","doi":"10.2298/tsci2303109l","DOIUrl":"https://doi.org/10.2298/tsci2303109l","url":null,"abstract":"Given the background of the rural population ageing, the reduced agricultural non-point source pollution and the decreased agricultural carbon emission, agricultural producer services, as an important bridge between small farmers and modern agriculture, are an important path to ensure food security and the green development of agriculture. Based on panel data of 31 provinces in China from 2003 to 2020, this paper uses Slack-based measure model with undesirable outputs (SBM-undesirable model)to calculate the agricultural ecological efficiency of 31 provinces. Furthermore, the two-stage least squares, the panel threshold model and the spatial Durbin model are used to empirically analyze the influence mechanism and the spatial spillover effect of agricultural productive services on agricultural ecological efficiency. The results show that agricultural producer services have a significant non-linear impact on agricultural ecological efficiency. Rural residents' income and per capita cultivated land area can adjust the relationship between them. The two main ways for agricultural productive services to improve agricultural ecological efficiency are as follows: reducing undesirable outputs such as pesticides, chemical fertilizers and plastic sheeting for agricultural use and improving agricultural production efficiency. In addition, agricultural producer services have a significant positive spatial spillover effect on agricultural ecological efficiency, and the indirect impact elasticity of spatial spillover is higher than the direct impact elasticity. Therefore, to achieve food security and promote the sustainable development of agriculture, it is necessary to vigorously develop agricultural productive ser-vices through multiparty cooperation.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68261415","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

The study of heat characteristics for micro pin-fin heat sinks with different structures 不同结构微鳍片散热器的热特性研究

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci230311175k

Nailiang Kuang, Guoran Lu, Kui Li, Yanmei Kong, Jiangbin Zheng, Binbin Jiao

{"title":"The study of heat characteristics for micro pin-fin heat sinks with different structures","authors":"Nailiang Kuang, Guoran Lu, Kui Li, Yanmei Kong, Jiangbin Zheng, Binbin Jiao","doi":"10.2298/tsci230311175k","DOIUrl":"https://doi.org/10.2298/tsci230311175k","url":null,"abstract":"Heat flux in electronic devices has increased dramatically with the development of advanced IC technology, facing the demand for effective thermal management technology. Micro pin-fin heat sink (MPFHS) has been demonstrated to be capable of improving the heat transfer capability and suppressing temperature rise effectively. In order to elaborate the discrepancy of heat dissipation of the MPFHS due to the cross-section shapes of pin-fin structures a set of heat sink samples with four different shapes, including the Circle-MPFHS, the Square-MPFHS, the Crisscross-MPFHS and the Octagon-MPFHS, are fabricated with micromachining technology. Then, the thermal characteristics are tested by integrating the heat sinks with a Pt film resistor chip as the heating source, and nucleate boiling phenomenon was observed with a high-speed camera. Results showed that concave corners in pin-fin structures increased the specific surface area, but generated low-velocity vortexes in back flow regions, reducing the heat transfer capability. The heat transfer coefficients of the Octagon-MPFHS, the Crisscross-MPFHS and the Circle-MPFHS was increased by 161.9 %, 152.4% and 85.7 % respectively relative to the Square-MPFHS at the flow rate of 147 kg/m2s. The heat transfer coefficients of the Octagon-MPFHS, the Crisscross-MPFHS, the Circle-MPFHS and the Square-MPFHS was increased by 7.27 %, 11.32 %, 2.56 % and 4.76 % when the mass flow rate was increased from 147 kg/m2?s to 295 kg/m2s. The nucleate boiling phenomenon in the Crisscross-MPFHS showed periodicity and positive feedback effect, resulting in local dry-out and consequent heat transfer capability deterioration. This study will contribute to the design and modification of MPFHS.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68261823","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

Damage mechanism of concrete with recycled brick aggregate 再生砖骨料混凝土损伤机理研究

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2303145w

Zhengjiang Wang, Yang Yang, Y. Su, J. Wang, Zhongping Wei, Yajuan Li, Jiawei Li, Chao Zhu

引用次数: 0

Estimation of reliability in multicomponent stress-strength based on exponential Frechet distributions 基于指数Frechet分布的多分量应力强度可靠性估计

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2303747s

Li-Feng Shang, Zai-zai Yan

引用次数: 0

Operational characteristics of the CHP plant in the district heating system of Belgrade 贝尔格莱德区域供热系统热电联产电厂的运行特点

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci230405158t

V. Tanasić, N. Tanasić, M. Stamenić

{"title":"Operational characteristics of the CHP plant in the district heating system of Belgrade","authors":"V. Tanasić, N. Tanasić, M. Stamenić","doi":"10.2298/tsci230405158t","DOIUrl":"https://doi.org/10.2298/tsci230405158t","url":null,"abstract":"The combined production of electricity and thermal energy (CHP or cogeneration) is the most efficient and convenient approach to reduce costs for energy at industrial power plants and district heating plants that use natural gas as fuel to produce thermal energy for various needs. This paper analyses the operational characteristics of the CHP plant, which has been operating since January 1, 2021, at the Vozdovac Heating Plant as part of the Belgrade district heating system. The CHP plant consists of three gas engine units with a total nominal electric power of 10 MW and thermal power of 10.1 MW, which use natural gas as fuel. The CHP plant is used for district heating and preparing domestic hot water (DHW) while electricity is sold to the local electric grid. The analysis in this paper focuses on the plant's operational characteristics: the number of working hours, the total energy consumption and energy production, the efficiency as well as the operational and maintenance costs. Also, the impact of the drastic changes in the prices of natural gas, electricity, and maintenance costs in the last year on the financial profitability of the CHP plant was analysed in particular.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68263511","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

Numerical solution for stochastic heat equation with Neumann boundary conditions 具有Neumann边界条件的随机热方程的数值解

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci23s1057r

S. Raja Balachandar, D. Uma, H. Jafari, S. Venkatesh

引用次数: 0

Local meshless collocation scheme for numerical simulation of space fractional PDE 空间分数阶偏微分方程数值模拟的局部无网格配置方案

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci23s1101s

M. Shakeel, M. Khan, I. Ahmad, H. Ahmad, Nantapat Jarasthitikulchai, W. Sudsutad

引用次数: 7

Analytical and computational results for boundary-layer equations in porous medium 多孔介质边界层方程的解析与计算结果