Effect of Testing Conditions on Performance and Durability of Stabilisers in Plastics

2003 ◽  
Vol 11 (2) ◽  
pp. 81-90 ◽  
Author(s):  
J. Pospíšil ◽  
Z. Horák ◽  
J. Pilař ◽  
S. Nešpurek ◽  
N. C. Billingham ◽  
...  

The accelerated thermal aging and weathering of stabilised plastics provides information on stabiliser efficiency and polymer durability more quickly than natural testing. This allows the monitoring of the material properties of plastics in the foreseen application environment and the development of new stabilisation formulations. The harshness of the testing method affects the individual processes involved regarding their activation energies and mechanisms, the physical relations in the polymer – stabiliser system, and the chemical and physical processes accounting for the consumption of stabilisers. The principal factors affecting any comparison of accelerated results with natural testing are outlined.

2007 ◽  
Vol 37 (10) ◽  
pp. 1821-1831 ◽  
Author(s):  
Sen Wang ◽  
C. Tyler DesRoches ◽  
Lili Sun ◽  
Brad Stennes ◽  
Bill Wilson ◽  
...  

This paper has three main objectives: (i) to investigate whether the four-quadrant approach introduced by     J.S. Maini reveals a useful typology for grouping countries by gross domestic product (GDP) and forest cover per capita, (ii) to determine if the framework can enhance our understanding of the relationship between forest cover and GDP per capita, and (iii) to investigate why countries in the four-quadrant world occupy different quadrants and to determine the principal factors affecting country movement across and within the individual quadrants. The examination reveals that countries can be classified into four broad categories and that GDP and forest cover per capita have a low but consistent level of negative association. After regressing economic, institutional, social capital, and other variables on a country’s occupancy and movement in the four-quadrant world, the results suggest that countries in each quadrant share different characteristics and that factors underlying country movement vary according to the quadrant being observed. Overall, countries with less corruption and higher education are likely to experience increases in both forest cover and GDP per capita, while countries exporting a significant proportion of forest products have a reduced probability of increasing both variables.


1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.


Author(s):  
Jinbao Zhang ◽  
Jaeyoung Lee

Abstract This study has two main objectives: (i) to analyse the effect of travel characteristics on the spreading of disease, and (ii) to determine the effect of COVID-19 on travel behaviour at the individual level. First, the study analyses the effect of passenger volume and the proportions of different modes of travel on the spread of COVID-19 in the early stage. The developed spatial autoregressive model shows that total passenger volume and proportions of air and railway passenger volumes are positively associated with the cumulative confirmed cases. Second, a questionnaire is analysed to determine changes in travel behaviour after COVID-19. The results indicate that the number of total trips considerably decreased. Public transport usage decreased by 20.5%, while private car usage increased by 6.4%. Then the factors affecting the changes in travel behaviour are analysed by logit models. The findings reveal significant factors, including gender, occupation and travel restriction. It is expected that the findings from this study would be helpful for management and control of traffic during a pandemic.


2017 ◽  
Vol 9 ◽  
pp. 184797901771262 ◽  
Author(s):  
Ahmad Adnan Al-Tit

Numerous studies have been conducted to explore the individual effects of organizational culture (OC) and supply chain management (SCM) practices on organizational performance (OP) in different settings. The aim of this study is to investigate the impact of OC and SCM on OP. The sample of the study consisted of 93 manufacturing firms in Jordan. Data were collected from employees and managers from different divisions using a reliable and valid measurement instrument. The findings confirm that both OC and SCM practices significantly predict OP. The current study is significant in reliably testing the relationship between SCM practices and OP; however, it is necessary to consider cultural assumptions, values and beliefs as the impact of OC on OP is greater than the impact of SCM practices. Based on the results, future studies should consider the moderating and mediating role of OC on the relationship between SCM practices and OP.


2021 ◽  
Vol 18 (1) ◽  
pp. 80-94
Author(s):  
D. I. Prokhor ◽  
◽  
N. V. Grachev ◽  

Objective: An equivalent mode of accelerated thermal aging of the insulation system of electrical ma- chines is described to confirm the resource corresponding to a given period and operating conditions. Methods: The equivalent mode of accelerated heat aging was determined based on the Montzinger rule and tested in the course of research and development work (R&D) on the development, manufacture and implementation of a set of bench and operational tests of the insulation system of an increased heat resistance class of a diesel locomotive traction motor. Results: The relevance of R&D has been revealed, as a result of which the implementation of the idea was required, based on the statement about the re- duction of the insulation resource of electrical machines when the permissible heating is exceeded by 8–12 °С to various types of insulating materials. The advantages of the method presented in the article in relation to traditional solutions of this problem are demonstrated, and also improved consumer proper- ties of the traction electric motor of a diesel locomotive with a replaced insulation system of an increased class of heat resistance are presented. Generally, experimental tests and preliminary operational data are an acceptable basis for thermal evaluation of electrical insulating materials. However, it is important to remember that the scientific criterion is met and not to use the results of different types of tests in the analysis. Based on the world experience in diagnostics of additional insulation parameters for monitoring the state of insulation parameters, the possibility of using the “Doctor” series insulation monitoring de- vices has been determined and practically confirmed. Together with the results of subsequent operational tests, during which the insulation was also monitored using these mobile devices, it is argued that after carrying out the relevant research work, thanks to the mobile devices of the “Doctor” series, it is pos- sible to carry out predictive analytics of the failure of traction motors (TED) in any operating conditions. The functional value is determined and applied in practice. The “H” class insulation system developed by the specialists of JSC “VNIKTI” is mainly based on insulating materials produced by JSC “Holding Company „Elinar“”; the compound “Elplast 180ID” (JSC “Electroizolit”) or its analogue “Elkom-180” JSC “Holding company „Elinar“”), for anchor coils and equalizers, a wound PPIPK-2 wire in polyimide- fluoroplastic insulation (GC “Moskabelmet”) is used. Practical importance: It is stated that all stages of manufacturing and testing, determined at the initial stage of R&D, confirmed the results of the deve- lopment stages (overhaul (manufacture) of prototypes of TED using a new isolation system according to the design documentation of JSC “VNIKTI”). Bench tests have confirmed typical characteristics, speci- fied resource and insulation characteristics with equivalent accelerated thermal aging corresponding to an electric motor’s service life of 20 years in ordinary operation on a diesel locomotive, residual life of elements of the insulation system of naturally cut armature segments, main and auxiliary poles coils. In the specialized laboratory of JSC “Holding Company „Elinar“”, an experimental TED diesel locomotive set with the investigated insulation system was manufactured and installed on two sections of the main- line diesel locomotive 2TE116. Operational tests of an experimental TED diesel locomotive set under operating conditions were successful.


2014 ◽  
Vol 644-650 ◽  
pp. 5644-5647
Author(s):  
Kang Shao ◽  
Hui Xu ◽  
Kun Wang

With the rapid development of e-commerce, online store, characterized in less investment and operating flexibility, are favored by more entrepreneurs. This paper analyzes the principal factors, affecting the competitiveness of online clothing shop, based on third-party platform with online sales of conduct, and the intrinsic link between them. And emphasis should be placed on the network store management, target market, products value, service quality, network store promotion, prestige image and logistics services to cultivate and raise the competence of network store so as to get unique competitive edges.


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