نتایج جستجو برای: chlorofluorocarbons

تعداد نتایج: 647  

Journal: :The Medical journal of Malaysia 2013
Yadav H

The International Medical University has a Community and Family Case Study (CFCS) programme as part of the training for medical students. The aim of the programme is to emphasize the family and community perspective of patient care in the home environment. A cross-sectional descriptive study was done among 66 final year medical students using a questionnaire. The students were in the 10th Semes...

2014
K. Nakatani M. Ikoma K. Arita

four kinds of refrigerant mixtures R22/Rl34a, R22/Rl52a, R22/Rl42b and R22/Rl23, which contain some new halocarbons which are considered to be the alternatives for CFCs, were evaluated in order to realize higher condensing temperature than that using R22 at high temperature operation, and larger heating capacity than that using R22/Rll4 at normal temperature operation. These mixtures were appli...

2014
I. R. Shankland R. S. Basu D. P. Wilson

THE~$L CONDUCTIVITY AND VISCOSITY OP A NEW STRATOSPHERICALLY SAFE REPRIGERANT1,1,1,2-TETRAPLUOROETHANE (R-l34A) I. R. Shankland R. s. Basu D. P. Wilson GenetronR Products Laboratory Allied-Signal, Inc. 20 Peabody st. Buffalo, NY 14210 Recent hypothesis on stratospheric ozone deple tion by chlorofluorocarbons has prompted industry to lo ok for environmentally safe alternates to refrigerants such...

2006
K. Friis R. G. Najjar M. J. Follows S. Dutkiewicz

[1] We argue that diagnostics of excess dissolved calcium carbonate (TA*) above the saturation horizon cannot be unambiguously interpreted in terms of local in situ dissolution. We examine a three-dimensional numerical model of global ocean circulation and biogeochemistry with explicit representation of the formation and dissolution of calcium carbonate. In particular, dissolution is only allow...

2001
Matthew H. England

Chemical tracers can be used to assess the simulated circulation in ocean models. Tracers that have been used in this context include tritium, chlorofluorocarbons, natural and bomb-produced radiocarbon, and to a lesser extent, oxygen, silicate, phosphate, isotopes of organic and inorganic carbon compounds, and certain noble gases (e.g., helium and argon). This paper reviews the use of chemical ...

Journal: :Nature communications 2014
Teng-Hao Chen Ilya Popov Watchareeya Kaveevivitchai Yu-Chun Chuang Yu-Sheng Chen Olafs Daugulis Allan J Jacobson Ognjen Š Miljanić

Metal-organic and covalent organic frameworks are porous materials characterized by outstanding thermal stability, high porosities and modular synthesis. Their repeating structures offer a great degree of control over pore sizes, dimensions and surface properties. Similarly precise engineering at the nanoscale is difficult to achieve with discrete molecules, since they rarely crystallize as por...

2014
F. de Rossi P. Mazzei

A soft~are packcage for both the thermodynamic properties computa-~ic~and tne analysis of usual vapor compression plant schemes is anusefu: tool for air conditioning and refrigeration researchers and mani-facture>s. At ~hePresent time, it could sUPPlY an important contribu-tion to search for CFCs substitutes; in fact, comparisons between two ormore ~o•king fluids...

2008
Mara G. Freire Abel G. M. Ferreira Isabel M. A. Fonseca Isabel M. Marrucho João A. P. Coutinho

In spite of their interest, viscosities of fluorocarbon compounds are scarce, and the available data are unreliable and of poor accuracy. In this work, viscosity measurements of linear, cyclic, aromatic, and R-substituted perfluorocarbons were carried out in the temperature range between (298.15 and 318.15) K using an Ubbelohde viscometer. The experimental results show that fluorinated compound...

2014
R. E. Foster G. W. McDonald

Evaporative air cooling is an effective and environmentally benign method of cooling. Scientific evidence demonstrating that chlorofluorocarbon refrigerants (CFCs) are contributing to the destruction of the stratospheric ozone layer have prompted legislative action aimed at reducing the production and use of certain CFCs. Enacted legislation, by necessitating the introduction and use of alterna...

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