scholarly journals Interpretation of measurements results of ice content in freezing mortars using DSC method

2013 ◽  
Vol 12 (3) ◽  
pp. 209-214
Author(s):  
Piotr Stępień ◽  
Zbigniew Rusin ◽  
Przemysław Świercz
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Thermal Effects ◽  
Temperature Differential ◽  
Technical Literature ◽  
Specific Process ◽  
Heat Flows ◽  
Cement Mortars ◽  
Ice Content ◽  
Dsc Method

The results of investigations of heat flows recorded at the low temperature differential scanning calorimeter (DSC) in the freezing cement mortars soaked with water are presented. Methods for extracting the thermal effects associated with the phase change of water as well as the methods for calculating the weight of ice with reference to the specific process temperature at which the phenomenon occurs are analyzed. It is found that computation assumptions and technical limitations of the calorimeter described in the technical literature can lead to significantly different results of determining the mass of formed ice.

METHODS FOR RESTORING WOLVES OF ROLLING PRODUCTION

2020 ◽  
Vol 4 (141) ◽  
pp. 114-122
Author(s):  
DAR’YA LEBEDEVA ◽  
◽  
ANNA KARPUNICHEVA
Keyword(s):  
Thermal Effects ◽  
Machine Building ◽  
Research Purpose ◽  
Technical Literature ◽  
Production Methods ◽  
Advantages And Disadvantages ◽  
Rolling Production ◽  
Machine Parts ◽  
The Stability ◽  
High Degree

Large forces and significant thermal effects are created on the rolls when rolling sheets. The higher the stability of the rolls, the less downtime during their rerolling and higher productivity. (Research purpose) The research purpose is in analyzing the ways of restoring rolls and choose the most appropriate method for restoring these parts. (Materials and methods) The article presents the analysis of the scientific and technical literature on the topic of rolling production, methods for restoring large-sized machine parts of machine-building and metallurgical industries that work in difficult conditions and are subject to a high degree of wear. Authors try to solve the problem by means of comparative and logical analysis based on theoretical and empirical methods of scientific research. (Results and discussion) The article presents two groups of methods for restoring rolled rolls: banding and surfacing the working layer of the roll. Authors have analyzed each method in terms of technology, equipment, and feasibility. The article presents the advantages and disadvantages of the methods under consideration. (Conclusions) The most acceptable way to restore parts with a high degree of wear is surfacing. It is most efficient to apply submerged surfacing using an additional hot additive. Such surfacing, despite some complication of the equipment design, allows to deposit the metal on the roll with low heat input and in most cases in one pass. Surfacing using an additional hot additive allows to increase the productivity of the process by up to 250 percent while reducing the penetration depth by 2-3 times and saving energy by up to 40 percent.

Reversible low temperature phase change and twinning in lithium acetyl acetonate

2009 ◽  
Vol 82 (3) ◽  
pp. 211-220 ◽  
Author(s):  
Calvin A. Austin ◽  
Brian D. Leskiw ◽  
Matthias Zeller
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Temperature Phase ◽  
Low Temperature Phase ◽  
Acetyl Acetonate

scholarly journals Thermal-Flow Analysis of a Simple LTD (Low-Temperature-Differential) Heat Engine

Energies ◽  
2017 ◽  
Vol 10 (4) ◽  
pp. 567 ◽  
Author(s):  
Yeongmin Kim ◽  
Wongee Chun ◽  
Kuan Chen
Keyword(s):  
Low Temperature ◽  
Heat Engine ◽  
Flow Analysis ◽  
Thermal Flow ◽  
Temperature Differential ◽  
Differential Heat

scholarly journals Experimental study on the compression characteristics of soft soil based on low temperature effect

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Jian Zhang ◽  
◽  
Chunpeng Han ◽  
Jiayi Tian ◽  
Qingjie Dong ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Compression Test ◽  
Variable Temperature ◽  
Soft Soil ◽  
Test Methods ◽  
Variable Load ◽  
Compression Tests ◽  
Different Temperatures ◽  
Freezing Condition

Based on the characteristics of long annual freezing time and short suitable construction period of soft soil in cold region, this paper discusses the feasibility of foundation treatment of soft soil in freezing-thawing layer under freezing condition. The deformation characteristics of soft soil in freezing-thawing layer in Hulunbuir area in China are studied by using two compression test methods, namely, constant temperature and variable load (CTVL) test, variable temperature and variable load (VTVL) test. The compressibility indexes under different temperatures and consolidation pressures are obtained. The research shows that the freezing-thawing soft soil has large compressibility, the maximum strain of CTVL test is 19.89%, and the maximum compression of VTVL test can reach 18.16%. The results of CTVL compression tests show that when the soil temperature is in the range of severe phase change (-1.5℃-0℃), the temperature change has the greatest influence on the compression coefficient of soil. The result of VTVL compression test shows that some additional deformation occurs under the action of low temperature. The additional deformation is further increased when the soil is under high consolidation pressure and in the severe phase change (-1.5℃-0℃).

scholarly journals Analysis of heat and mass transfer mechanism during thermal energy storage and temperature regulation

2020 ◽  
Vol 24 (5 Part B) ◽  
pp. 3185-3193
Author(s):  
Sina Dang ◽  
Hongjun Xue ◽  
Xiaoyan Zhang ◽  
Chengwen Zhong
Keyword(s):  
Mass Transfer ◽  
Energy Storage ◽  
Low Temperature ◽  
Phase Change ◽  
Heat And Mass Transfer ◽  
Latent Heat ◽  
Temperature Regulation ◽  
Phase Change Materials ◽  
Heat Energy ◽  
Temperature Environment

To strengthen the heat and mass transfer capacity and improve the temperature regulation rate, potential storage is taken as the research object in this research to study the heat energy storage of the battery in the low temperature environment. Lattice Boltzmann method is adopted to study the heat energy storage influence mechanism of the temperature regulation system of the low temperature phase-change materials. In addition, the influence of different physical parameters (thermal conductivity and latent heat of phase change) on the thermal insulation of the system in the process of temperature control is revealed. The results show that the mechanism of heat and mass transfer in the process of heat storage and temperature control is related to the different physical properties of phase change materials. The decrease of thermal conductivity and the increase of latent heat of phase change materials will greatly increase the effect of heat energy storage. Therefore, under the action of phase change latent heat, phase change material can effectively extend the holding time of the battery in the low temperature environment.

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