scholarly journals Study on the Compatibility of Eco-Friendly Insulating Gas C5F10O/N2 and C5F10O/Air with Copper Materials in Gas-Insulated Switchgears

2020 ◽  
Vol 11 (1) ◽  
pp. 197
Author(s):  
Yalong Li ◽  
Xiaoxing Zhang ◽  
Yalong Xia ◽  
Yi Li ◽  
Zhuo Wei ◽  
...  
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Sulfur Hexafluoride ◽  
Electrical Equipment ◽  
Copper Surface ◽  
Gas Mixture ◽  
Stable Operation ◽  
The World ◽  
Potential Alternative ◽  
Materials Used

Sulfur hexafluoride (SF6) is widely used in the power industry because of its excellent insulation and arc extinguishing performance. However, the high greenhouse effect of this material is being restricted by many countries around the world, thereby discouraging its usage. As a potential alternative to SF6, the compatibility of C5F10O with conductive copper materials used in electrical equipment is of great significance in ensuring the safe and stable operation of environmentally friendly gas-insulated equipment. In this paper, the interaction among C5F10O/N2, C5F10O/air gas mixture, and copper was studied via experiments and simulations. When the C5F10O/N2 (or air) gas mixture comes in contact with copper at the gas–solid interface, a small portion of C5F10O is decomposed to form C3F6 (or C3F6 and C3F6O) at high temperatures. Meanwhile, at low temperatures (120 °C), the C5F10O/air gas mixture becomes more compatible with copper than with the C5F10O/N2 gas mixture. When the experiment temperatures range between 170 °C and 220 °C, the compatibility of the C5F10O/air gas mixture with copper is significantly inferior to its compatibility with copper. Under high temperatures, the C5F10O/air gas mixture shows severe corrosion on the copper surface due to the presence of O2, forms a thick cubic grain, and emits irritating gases. The simulations show that the carbonyl group in C5F10O is chemically active and can be easily adsorbed on the copper surface. An anti-corrosion treatment must be performed on copper materials in manufacturing equipment. The findings provide an important reference for the application of C5F10O gas mixture.

scholarly journals The conductivity of heat insulators

1900 ◽  
Vol 65 (413-422) ◽  
pp. 283-288 ◽  
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Comparative Efficiency ◽  
The Subject ◽  
Materials Used

The comparative efficiency of materials used as insulators has been the subject of several investigations ; the majority of these have been conducted at fairly high temperatures, and it may be questioned whether the results can be applied to the same materials when used as a lagging to protect bodies at low temperatures. Moreover the methods adopted do not seem susceptible of any considerable accuracy.

scholarly journals The thermal stresses in spherical shells concentrically heated

1922 ◽  
Vol 100 (705) ◽  
pp. 379-394 ◽  
Keyword(s):  
High Temperatures ◽  
Simple Form ◽  
Low Temperatures ◽  
Thermal Stresses ◽  
Spherical Shells ◽  
Minimum Number ◽  
Glass Furnaces ◽  
Mathematical Difficulties ◽  
Materials Used ◽  
Set Up

1. In recent years there have been a number of failures of materials when unequally heated which appeared to be due to the stresses set up by the differences of temperature in the materials. These stresses, although unimportant for small differences of temperature and at low temperatures, may be serious for large differences at high temperatures, owing to their increase with the temperature differences and to the great reduction of the elasticities and ultimate strengths of materials at high temperatures. It is therefore desirable, when possible, to calculate the thermal stresses to which structures are liable to be subjected by the differences of temperature likely to exist in them, especially if these differences are large and the temperatures themselves high. The circumstances producing high thermal stresses are present to an exceptional degree in metallurgical, pottery and glass furnaces, and it is in these cases that disintegration of the materials used in the construction of the furnaces is most marked. The furnaces themselves vary so much in shape and material that it is advisable at present to discuss only some simple form and material, the investigation of which presents the minimum number of mathematical difficulties.

Administrasi Kurikulum

2019 ◽  
Author(s):  
Riga Sari ◽  
Hade Afriansyah
Keyword(s):  
Science And Technology ◽  
Curriculum Evaluation ◽  
Learning Activities ◽  
Educational Institutions ◽  
Educational Goals ◽  
Curriculum Management ◽  
Learning Materials ◽  
The World ◽  
Institutional Learning ◽  
Materials Used

This article describe about curriculum. The curriculum is a set of plans and arrangements regarding the objectives, content, and learning materials and materials used as guidelines for the implementation of learning activities to achieve certain educational goals. Administration of the curriculum is a system of curriculum management that is cooperative, comprehensive, systemic, and systematic in order to realize the achievement of curriculum objectives. The aim of the curriculum is to achieve institutional learning at educational institutions, so that the curriculum plays an important role in realizing quality and quality schools. The method used in this study includes planning, implementation, supervision, and curriculum evaluation. Thus it can be seen that a good curriculum is a curriculum that follows the development of science and technology based on society. Failure in the administration of a curriculum will have fatal consequences on the success of the world of education.

Low solubility of alumina in enstatite and uncertainties in estimated palaeogeotherms

1978 ◽  
Vol 288 (1355) ◽  
pp. 471-486 ◽  
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Alumina Content ◽  
Equilibrium Solubility ◽  
Low Solubility

Spurious kinks in estimated palaeogeotherms may result from small errors in the calibration of the geothermometers and geobarometers. New data indicate that the equilibrium solubility of alumina in enstatite is even less than shown by recent studies, and that the slopes (d T /d P ) of the isopleths of equal alumina content are steeper than hitherto believed. Consequently, pressures of equilibration estimated from current formulations of the orthopyroxene-garnet geobarometer will be too high at high temperatures (> 1200 °C) and too low at low temperatures.

scholarly journals Environmental temperature during early life affects the personality of mosquitofish in adulthood

2021 ◽  
Author(s):  
Haifeng Li ◽  
Xinyu ZHang ◽  
Yi Wu ◽  
Feng ZHang ◽  
CHunlin Li
Keyword(s):  
Body Length ◽  
High Temperatures ◽  
Low Temperatures ◽  
Early Life ◽  
Environmental Temperature ◽  
Phenotypic Trait ◽  
Behavioral Syndrome ◽  
Growing Up ◽  
Female Fish ◽  
Behavioral Traits

Abstract Personality has been observed in a variety of animal taxa with important implications in ecology and evolution. Exploring the influence of environmental temperature during early life on personality could help to understand the ontogeny of this phenotypic trait in animals. In this study, we reared newborn mosquitofish Gambusia affinis at high (30°C) and low (25°C) water temperatures and measured their shyness and exploration upon sexual maturity. We tested the repeatability of each behavioral trait; the correlation between them; and the effects of rearing temperature, sex, and body length on the behaviors. When growing up at low temperatures, female fish exhibited repeatability in shyness and exploration, and males exhibited marginal repeatability in shyness. However, neither of the 2 behaviors were repeatable when the fish were reared at high temperatures. There was a negative correlation between shyness and exploration, indicating that the 2 behaviors comprise a behavioral syndrome in this species. Mosquitofish reared at high temperatures were more explorative than those reared at low temperatures, while there was no difference in shyness between the 2 treatments. Body length and sex had no significant effects on the average values of the 2 behaviors. The results indicate that environmental temperature during early life could shape the personality of mosquitofish and modify the average of the behavioral traits. These findings might provide insights to understand the ontogeny of animal personality and how changes in environmental temperature influence animal dispersal by shaping their personality.

scholarly journals Review of Multi-Physics Modeling on the Active Magnetic Regenerative Refrigeration

2021 ◽  
Vol 26 (2) ◽  
pp. 47
Author(s):  
Julien Eustache ◽  
Antony Plait ◽  
Frédéric Dubas ◽  
Raynal Glises
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
Room Temperature ◽  
State Of The Art ◽  
Vapor Compression ◽  
Crucial Step ◽  
Potential Alternative ◽  
Vapor Compression Refrigeration ◽  
Preliminary Study ◽  
Physics Modeling

Compared to conventional vapor-compression refrigeration systems, magnetic refrigeration is a promising and potential alternative technology. The magnetocaloric effect (MCE) is used to produce heat and cold sources through a magnetocaloric material (MCM). The material is submitted to a magnetic field with active magnetic regenerative refrigeration (AMRR) cycles. Initially, this effect was widely used for cryogenic applications to achieve very low temperatures. However, this technology must be improved to replace vapor-compression devices operating around room temperature. Therefore, over the last 30 years, a lot of studies have been done to obtain more efficient devices. Thus, the modeling is a crucial step to perform a preliminary study and optimization. In this paper, after a large introduction on MCE research, a state-of-the-art of multi-physics modeling on the AMRR cycle modeling is made. To end this paper, a suggestion of innovative and advanced modeling solutions to study magnetocaloric regenerator is described.

scholarly journals Faux Fur Trade Networks Using Macroscopic Data: A Social Network Approach

2021 ◽  
Vol 13 (3) ◽  
pp. 1427
Author(s):  
Yeong-Hyeon Choi ◽  
Seong Eun Kim ◽  
Kyu-Hye Lee
Keyword(s):  
Social Network ◽  
The United States ◽  
Asian Countries ◽  
Total Trade ◽  
Trade Networks ◽  
Alternative Materials ◽  
The World ◽  
Social Network Approach ◽  
Materials Used ◽  
And Control

This study used social network analysis, which is often adopted to analyze changes in trade structures and the world trade network for faux fur products, which are alternative materials used in vegan fashion. The data on the total trade value of artificial fur (HS Code: 4304) and animal fur and leather (HS Code: 0505) imports and exports between countries were collected through UN Comtrade, and the degree and betweenness centralities were used to analyze the trade structure of faux fur in 2009, 2014, and 2019 using NodeXL 1.0.1 programs. The results of the study are as follows: First, while the total amount of export and import of faux fur is increasing globally every day, the total amount of export and import in other Asian countries and Vietnam is decreasing. Second, due to the reduction in exports of the main producing countries of animal materials such as China, global imports of animal fur and leather decreased. Third, China was the largest ex-porter of faux fur, exporting to a large number of countries; it also played an important role in the intermediation and control over faux fur export. In exporting faux fur, the influence of other Asian countries declined over time, and Vietnam and the United States played an outstanding role as arbitrators in the export network. Fourth, Italy and France were the largest importers of faux fur from various countries and exerted significant influence as intermediaries in the import network of faux fur. On the other hand, Vietnam’s influence in import network decreased. Saudi Arabia appeared to be an important arbitrator in mediating the import. This study is significant due to its findings, obtained through micro-trading data, in respect of industrial moves of ethical fashion in the form of increased trade in faux fur and decline in the trade of animal fur and leather.

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