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Abstract: The article is a synopsis of the 9 papers in the field of cryobiology, particularly regarding the use of modern cryopreservation and related techniques for conservation of genetic resources of endangered species and economically important breeds of wild and domesticated animals and plants published in this issue of the International Journal of Refrigeration. The papers are related to vitrification, primarily of reproductive and progenitor cells as a swiftly expanding and effective approach of biostabilization, as well as to cryopreservation of spermatozoa, leucocytes, and other cells of the humans, sturgeon species, European mink, marine invertebrates, and plants. A brief introduction to cryobiology and related fields is also provided. [Copyright &y& Elsevier]

Copyright of Canadian Journal for the Study of Adult Education is the property of Canadian Journal for the Study of Adult Education and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Regional Studies is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper reviews the progression in refrigerants for chillers, from historical selections through current options and projections for the future. It examines the global environmental issues that catalyzed recent changes. It then discusses candidate refrigerants in the context of future availability (or phaseout) based on controls for environmental protection, efficiency, toxicity, flammability, and escalating future costs. It notes that negative marketing and conflicting claims, intended to discredit competitor''s approaches, create confusion and retard replacement of older, less-efficient equipment. The result hurts the environment, increases costs, and stifles the chiller market. The paper concludes that most of the current anxiety with refrigerant selections is unwarranted. Engineers, building owners, and others involved in chiller decisions should revert to traditional chiller specifications based on cost, performance, local manufacturer support, service options, and reliability. Anticipating more stringent environmental regulations, they also should take all practical steps to reduce refrigerant releases and increase efficiency. The paper examines future refrigerant options for chillers. Noting that there are no ideal refrigerants and that none are likely to be found, it recommends scientific determination of acceptability rather than market manipulation. [Copyright &y& Elsevier]

Copyright of Opinião Pública is the property of Universidade Estadual de Campinas - Portal de Periodicos Eletronicos Cientificos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Bioethics / Revue canadienne de bioéthique is the property of Ecole de Sante Publique de l'Universite de Montreal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cartes et Géomatique is the property of Comite Francais de Cartographie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Administrative Sciences (John Wiley & Sons, Inc.) is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Sociology is the property of Canadian Journal of Sociology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Strategy & Development Review is the property of Strategy & Development Review and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista EAN is the property of Universidad EAN and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Études Caribéennes is the property of Etudes Caribeennes and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Oerlemans L. A. G. and Meeus M. T. H. (2005) Do organizational and spatial proximity impact on firm performance?, Regional Studies 39 , 89-104. Recent theoretical developments in organization science, economic geography and regional economics have emphasized the importance of organizational and geographical proximity for the performance of firms. Empirical evidence on these relationships is scarce, though. The paper asks to what extent firm-specific resources, network activity, proximity and industry factors influence innovative and economic outcomes. We used a theoretical synthesis of regional and organizational science, and economic geography to build a research model that enabled us to derive several hypotheses on the influence of different forms of proximity on outcomes, taking other relevant predictors for performance into account. The empirical findings specify the importance of proximity especially for innovative outcomes. We found that in particular intra- and interregional relations with buyers and suppliers are conducive for firm performance. Moreover, innovation strategy (dis)similarity has interesting effects on relative firm performance. Finally, sectoral research and development spillovers influence outcomes in a positive way. Oerlemans L. A. G. et Meeus M. T. H. (2005) La proximité organisationnelle et géographique, importe-t-elle pour la performance des entreprises?, Regional Studies 39 , 89-104. De récentes avances théoriques dans la science organisationnelle, la géographie économique, et l'économie régionale ont souligné l'importance de la proximité organisationnelle et géographique pour la performance des entreprises. Cependant, rares sont les preuves empiriques sur ces rapports. Cet article cherche à déterminer dans quelle mesure les ressources spécifiques à l'entreprise, la constitution de réseaux, la proximité, et les facteurs liés à l'industrie influencent les résultats innovateurs et économiques. A partir d'un synthèse théorique de la science régionale et organisationnelle, et de la géographie économique, on construit un modèle de recherche qui permet d'obtenir plusieurs hypothèses sur l'influence de diverses formes de proximité sur les résultats, tout en tenant compte des autres moyens d'estimer la performance. Les résultats empiriques précisent l'importance de la proximité, surtout pour ce qui est des résultats innovateurs. Il s'avère en particulier que des rapports intra et interrégionaux avec les acheteurs et les vendeurs sont propices à la performance des entreprises. En outre, la(dis)similitude entre les stratégies en faveur de l'innovation a des effets intéressants sur la performance relative des entreprises. Pour finir, les retombées de R et D sectorielles influencent les résultats de façon positive. Oerlemans L. A. G. und Meeus M. T. H. (2005) Die Auswirkung organisatorischer und räumlicher Nähe auf Firmenleistung, Regional Studies 39 , 89-104. Die neuesten theoretischen Entwicklungen auf den Gebieten der Organisationswissenschaft, Wirtschaftsgeographie und Regionalwirtschaft haben die Bedeutung organisatorischer und geographischer Nähe für Firmenbildung betont. Es gibt jedoch nur wenig empirische Beweise für diese Beziehungen. In diesem Aufsatz wird die Frage aufgeworfen, in welchem Ausmaß firmenspezifische Ressourcen, Netzwerkunternehungen, Nähe und Industriefaktoren innovative und wirtschaftliche Ergebnisse beeinflussen. Die Autoren benutzen eine theoretische Synthese regionaler und organisatorischer Wissenschaften sowie der Wirtschaftsgeographie, um ein Forschungsmodell zu konstruieren, das sie in die Lage versetzt, verschiedene Hypothesen über den Einfluß unterschiedlicher Formen der Nähe auf Ergebnisse anzugeben, wobei andere relevante Voraussagefaktoren für Leistung in Rechnung gestellt werden. Die empirischen Befunde heben die Bedeutung der Nähe besonders für innovative Ergebnisse hervor. Es ergibt sich, daß der Firmenleistung vorallem intra-und interregionale Beziehungen zu Käufern und Lieferanten dienlich sind. Darüberhinaus üben (Un)ähnlichkeiten der Innovationsstrategien interessante Wirkungen auf relative Firmenleistung aus. Letztlich hat auch die Verbreitung von Forschung und Entwicklung einen positiven Einfluß auf die Ergebnisse. Oerlemans L. A. G. y Meeus M. T. H. (2005) Cómo afecta al rendimiento de las empresas la proximidad espacial y organizacional?, Regional Studies 39 , 89-104. Los desarrollos teóricos recientes en torno a la ciencia organizacional, la geografía económica y la economía regional han resaltado la importancia de la proximidad geográfica y organizacional para el rendimiento de las empresas. No obstante, la evidencia empírica en torno a dichas relaciones es escasa. En este artículo, nos planteamos hasta qué punto los recursos específicos de las empresas, actividades de networking , la proximidad y los factores industriales influyen los resultados económicos y de innovación. Utilizamos una síntesis teórica de la ciencia regional y organizacional, así como de la geografía económica, para elaborar un modelo de investigación que nos permitiera derivar una serie de hipótesis sobre la influencia de los diferentes tipos de proximidad en los resultados, teniendo en cuenta otros indicadores relevantes para el rendimiento. Nuestros resultados empíricos realzan la importancia de la proximidad especialmente para los resultados de innovación. Los resultados obtenidos demuestran que, en particular, las relaciones intra- e inter-regionales con compradores y proveedores conducen al rendimiento de las empresas. Además, la desemejanza entre las estrategias de innovación tiene efectos interesantes en el rendimiento relativo de las empresas. Finalmente, los efectos de arrastre de I&D sectoriales influyen en los resultados de forma positiva. [ABSTRACT FROM AUTHOR]

Copyright of Contemporary Accounting Research is the property of Canadian Academic Accounting Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ashcroft B. (1982) The measurement of the impact of regional policies in Europe: a survey and critique, Reg. Studies 16, 287–305. The paper examines the broad approaches and particular methods used to estimate the impact of regional policies in several European countries. The strengths and weaknesses of the major approaches are identified. The total effects, their components and the effects of individual policy instruments are considered. The theory and measurement of the costs and benefits of regional policy is examined. Some areas for further research are suggested. [ABSTRACT FROM PUBLISHER]

Copyright of ALTER: European Journal of Disability Research, Journal Europeen de Erche sur le Handicap is the property of European Society for Disability Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Romanica Olomucensia is the property of Palacky University in Olomouc and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Humanitas: International Journal of Social Sciences / Uluslararasi Sosyal Bilimler Dergisi is the property of Humanitas: International Journal of Social Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Population (00324663) is the property of Institut National d'Etudes Demographiques and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of ESSACHESS is the property of ESSACHESS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Different evaluations conducted on blood safety between 2004 and 2013 in Africa showed some progress in most countries. This paper describes the current status of the availability and access to safe blood in the Region. A cross-sectional survey was conducted from January to December 2018. Data were collected through a questionnaire prepared using key indicators of blood safety and analysis was done using Excel 2010 and results were compared to those of the 2013. A total of 2,678 blood centres were reported including 244 (9%) stand-alone and 2,434 (91%) hospital based. Amongst these countries, 90.2% had a blood policy, 60.1% participated in an External Quality Assessment Scheme for Transfusion Transmissible Infections screening, 12% had accredited blood services, 73.2% had national guidelines on clinical use of blood and 78% had a government budget. The total number of blood units collected was 4,899,913 and the average proportion of voluntary blood donations was 71%. Plasma-derived medicinal products were included in the national essential medicines list in 52.6% of countries. The average proportion of units of blood tested for infections was 99.5% for HIV, 92.3% for HBV, 98.9% for HCV, 98.8% for syphilis. The percentage of whole blood separated into blood components was 63.4%. Countries in the region continue to improve availability and access to safe blood, but challenges still remain and call for concrete actions required to reach universal access to quality and safe blood for transfusion throughout the region. [ABSTRACT FROM AUTHOR]

Des oppositions théoriques et épistémologiques ont jalonné l'histoire de la psychologie. L'hypothèse que nous évaluons ici est que ces oppositions sont soutenues, souvent de manière implicite, par des oppositions plus profondes, de nature philosophique, métaphysique, voire même religieuses. La question philosophique au cœur de cette étude concerne la dualité entre l'esprit et le cerveau et donc l'opposition classique entre dualisme et physicalisme. À l'aide d'un questionnaire qui a été adressé aux enseignants-chercheurs de 8 universités françaises, nous disposons désormais d'une représentation synthétique et précise du positionnement des enseignants-chercheurs issus des grandes sous-disciplines de la psychologie et des neurosciences. Au vu des résultats obtenus, il apparaît clairement que nos convictions philosophiques et métaphysiques sont extrêmement contrastées et révèlent des contradictions internes fortes au niveau même du fondement de notre discipline. Nous abordons dans la discussion l'impact de ces oppositions sur nos conceptions de la recherche comme de la pratique clinique. The history of psychology has been marked by strong methodological, theoretical and epistemological controversies. In this paper, we evaluate the hypothesis that these well-known controversies are often implicitly supported by philosophical, metaphysical and probably religious oppositions. The focus of our investigation concerns the classical opposition in philosophy between dualism and physicalism, more specifically the complex relationship between the brain and the mind. One hundred and sixty-six teachers and researchers (30 in clinical psychology, 37 in cognitive psychology, 31 in development psychology, 38 in social psychology and 30 in neurosciences) from 8 French universities have accepted to participate in this survey by responding to a questionnaire made of 17 questions. Data were analyzed using factor analysis technique and the results of the principal component analysis (PCA) revealed four main factors that are more likely to define accurately the philosophical profile of each sub-discipline. The main result of this survey is that philosophical and metaphysical positions, at the foundations of psychology, clearly distinguish and oppose the five studied sub-disciplines. At one extreme, there are cognitive psychologists and neuroscientists who are strongly physicalist. To the contrary, clinical and social psychologists exhibit more dualistic representation. Developmental psychologists occupy an intermediate position between these two extremes. Finally, we analyzed the implications of the participants' philosophical representation differences, from an epistemological and clinical/practical point of view. The important point is that these philosophical and metaphysical oppositions are largely implicit. Indeed, inside our community, it is very rare, if not exceptional, that they are explicitly involved in the theoretical or epistemological conflicts, which exist inside our discipline. However, it is probable that they play a massive role in our debates, a role all the more important, as we are largely unconscious of them. The current study is the first to tackle such an important topic by describing more accurately the philosophical representation of scholars in major sub-fields of psychology. By revealing such deep metaphysical oppositions, we hope to shed a new light on the origins of these persisting conflicts in psychology. [ABSTRACT FROM AUTHOR]

Abstract: This paper provides an exergy analysis for multistage cascade low temperature refrigeration systems used in olefin plants. The equations of exergy destruction and exergetic efficiency for the main system components such as heat exchangers, compressors and expansion valves are developed. The relations for total exergy destruction in the system and the system overall exergetic efficiency are obtained. Also, an expression for minimum work requirement for the refrigeration systems of olefin plants is developed. It shows that the minimum work depends only on the properties of incoming and outgoing process streams cooled or heated with refrigeration system and the ambient temperature. Using actual work input values, the exergetic efficiency of the low temperature cascade refrigeration system of a typical olefin plant is determined to be 30.88% indicating a great potential for improvements. The novelty of this paper includes the suggestions for increasing efficiencies, along with discussion about the reasons for deviation from reversible processes. [Copyright &y& Elsevier]

Abstract: Ammonia is widely used as a refrigerant in industrial systems for food refrigeration, distribution warehousing and process cooling. It has more recently been proposed for use in applications such as water chilling for air-conditioning systems but has not yet received widespread acceptance in this field. This review paper assesses the reasons why ammonia is so popular in industrial systems, the reasons why it is deemed less suitable for other applications and the possible benefits at local, national and international levels that might be gained by more general acceptance of ammonia as a refrigerant. The paper also considers other possible applications which might benefit from the use of ammonia as refrigerant. [Copyright &y& Elsevier]

Abstract: This paper studies refrigeration cycles in which plate heat exchangers are used as either evaporators or condensers. The performance of the cycle is studied by means of a method introduced in previous papers which consists of assessing the goodness of a calculation method by looking at representative variables such as the evaporation or the condensation temperature depending on the case evaluated. This procedure is also used to compare several heat transfer coefficients in the refrigerant side. As in previous works the models of all the cycle components are considered together with the heat exchanger models in such a way that the system of equations they provide is solved by means of a Newton–Raphson algorithm. Calculated and measured values of the evaporation and the condensation temperatures are also compared. The experimental results correspond to the same air-to-water heat pump studied in other papers and they have been obtained by using refrigerants R-22 and R-290. [Copyright &y& Elsevier]

Abstract: A new way to assess the performance of refrigeration system models is presented in this paper, based on the estimation of cycle parameters, such as the evaporation temperature which will determine the validity of the method. This paper is the first of a series which will also study the influence of the heat transfer coefficient models on the estimation of the refrigeration cycle parameters. It focuses on fin and tube evaporators and includes the dehumidification process of humid air. The flow through the heat exchanger is considered to be steady and the refrigerant flow inside the tubes is considered one-dimensional. The evaporator model is discretised in cells where 1D mass, momentum and energy conservation equations are solved by using an iterative procedure called SEWTLE. This procedure is based on decoupling the calculation of the fluid flows from each other assuming that the tube temperature field is known at each fluid iteration. Special attention is paid to the correlations utilised for the evaluation of heat transfer coefficients as well as the friction factor on the air and on the refrigerant side. A comparison between calculated values and measured results is made on the basis of the evaporation temperature. The experimental results used in this work correspond to an air-to-water heat pump and have been obtained by using R-22 and R-290 as refrigerants. [Copyright &y& Elsevier]

Abstract: Desiccant systems find applications in a very large variety of industrial and daily usage products including the new HVAC installations. An overview of liquid desiccant technology has been presented in this paper along with a compilation of experimental performance data of liquid desiccant dehumidifiers, empirical dehumidification effectiveness and mass transfer correlations in a useful and easy to read tabular format. The latest trends in this area suggest that hybrid systems are of current interest to HVAC industry, not only for high latent load applications but also for improving indoor air quality. The paper presents a comprehensive comparative parametric analysis of packed bed dehumidifiers for three commonly used desiccant materials viz. triethylene glycol, lithium chloride and calcium chloride, using empirical correlations for dehumidification effectiveness from the literature. The analysis reveals significant variations and anomalies in trends between the predictions by various correlations for the same operating conditions, and highlights the need for benchmarking the performance of desiccant dehumidifiers. [Copyright &y& Elsevier]

Abstract: This paper investigates the economic feasibility of a water-based vapor compression chiller with a nominal capacity of 3520kW (1000ton). Simplified models of potential cycle configurations are developed and used as a screening tool to identify a baseline cycle, the most attractive configuration for a water-based refrigeration machine. More detailed component-level models are developed to accurately size equipment and predict both the performance and cost of the baseline chiller. These component models address issues that are particularly crucial when water is used in refrigeration cycles, such as compression ratio, compressor discharge superheat and refrigerant-side pressure drop. Where possible, these component models are verified through comparison against the current state-of-the-art technology for large chillers that use R-134a as the refrigerant. The capital cost and expected operating costs are determined in order to quantify the payback and life-cycle costs associated with using water as a refrigerant, relative to traditional halocarbon refrigerants currently in use. Other issues that may have an economic impact on the feasibility of water as a viable alternative to traditional synthetic refrigerants are discussed, including purging and condensation within the compressor. The results show that water-based vapor compression refrigeration systems will not be economically attractive without substantial and successful efforts to develop low-cost, high capacity compressors. The paper provides an indication of the cost targets that must be met in order to make water vapor refrigeration systems practical. [Copyright &y& Elsevier]

Abstract: This paper reviews mathematical methods for modelling heat and mass transfer during the freezing, thawing and frozen storage of foods. It starts by considering the problems in modelling heat transfer controlled freezing (the Stefan problem): release of latent heat, sudden changes in thermal conductivity. The author gives a unified overview of the common numerical methods: finite difference, finite element and finite volume. Mass transfer is then considered, involving different phenomena and approaches for dense and porous foods. Supercooling, nucleation and trans-membrane diffusion effects during freezing, and recrystallization during frozen storage are considered next. High pressure thawing and thawing are considered in view of their recent popularity. Finally, the paper offers a brief look at mechanical stresses during freezing, a much neglected area. It is concluded that while modelling heat transferred controlled freezing is a settled problem, much work remains to be done in modelling associated phenomena in order to gain the ability to predict changes in food quality at the micro-level. [Copyright &y& Elsevier]

Abstract: This paper summarizes analyses of refrigerant options for chillers. It presents tabulated global warming potentials and other environmental data for candidate refrigerants. The paper discusses briefly the historic progression in refrigerant release reductions and presents analyses to compare the efficiencies of historic and current refrigerant options. The 28 refrigerants addressed include chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC), hydrocarbon (HC), and inorganic (such as ammonia) fluids. The paper discusses the relative importance of the refrigerant-related and energy-related components of chiller emissions. [Copyright &y& Elsevier]

Abstract: Although application of carbon dioxide as working fluid in many fields of refrigeration technology has been recommended very often in the recent past, the data on nucleate boiling heat transfer of carbon dioxide in free convection are very scarce in the open literature and new investigations are almost entirely focussed on forced convective flow boiling. In the interpretation of the respective results, heat transfer to carbon dioxide is often characterized as being superior to other refrigerants due to the outstandingly favourable thermophysical properties of carbon dioxide for boiling heat transfer. Different from this view, the discussion of recent results on pool boiling heat transfer of carbon dioxide in this review demonstrates that the high heat transfer coefficients measured for carbon dioxide in comparison to hydrocarbon or halocarbon refrigerants are mainly due to the fact that application of carbon dioxide is mostly envisaged for conditions where reduced saturation pressure p*=p s/p c (p c, critical pressure) is higher than for common refrigerants. In the first part of the review, the three main influences—by heat flux, saturation pressure and fluid properties—on pool boiling of carbon dioxide are discussed using recent measurements for CO2 by Kotthoff et al. [S. Kotthoff, U. Chandra, D. Gorenflo, A. Luke, New measurements of pool boiling heat transfer for carbon dioxide in a wide temperature range, Proceedings of the Sixth IIR-Gustav Lorentzen Conference, Glasgow, 2004 [paper 2/A/3.30]; see also S. Kotthoff, U. Chandra, D. Gorenflo, Neue Messungen zum Behältersieden von Kohlendioxid in einem grösseren Temperaturbereich, DKV-Tagungsbericht 22 (2004) [Bd.II. 1] 233–256 and other organic substances (Gorenflo et al.) [D. Gorenflo, S. Kotthoff, U. Chandra, New measurements of pool boiling heat transfer with hydrocarbons and other organics for update of VDI—Heat Atlas calculation method, Proceedings of the Sixth IIR-Gustav Lorentzen Conference, Glasgow, 2004 [paper 1/C/1.00]; Kotthoff and Gorenflo, [S. Kotthoff, D. Gorenflo, Influence of the fluid on pool boiling heat transfer of refrigerants and other organic substances, Proceedings of the IIR-Commission B1 Conference, Vicenza, 2005 [paper #TP-98]. In the second part, a comparison is given with the few former data available and with new results of Loebl and Kraus [S. Loebl, W.E. Kraus, Pool boiling heat transfer of carbon dioxide on a horizontal tube, Proceedings of the Sixth IIR-Gustav Lorentzen Conference, Glasgow, 2004 [paper 1/A/1.20]; S. Loebl, W.E. Kraus, Zum Wärmeübergang bei der Verdampfung von Kohlendioxid am horizontalen Rohr, DKV-Tagungsbericht 22 (2004) [Bd.II.1] 219–232 on the influence of the heating wall (material and surface roughness). Finally, analogies between nucleate pool boiling and new flow boiling data are shown for those domains of flow boiling in which nucleation provides the dominant contribution to heat transfer and convective effects are of secondary importance. [Copyright &y& Elsevier]

Abstract: Carbon dioxide has been used as a refrigerant in vapour compression systems of many types for over 130 years, but it is only in the last decade that inventive minds and modern techniques have found new ways to exploit the uniquely beneficial properties of this remarkable substance. This paper traces the development of the old carbon dioxide systems, considers the technical, commercial and social reasons for their slow development and subsequent decline and examines the recent renaissance across a surprisingly broad range of applications, from trans-critical car air conditioners to low temperature industrial freezer plants. The paper then concentrates on industrial refrigeration systems, which were the basis of early developments in the period 1865–1885, but which have been somewhat overlooked in the current renaissance. The paper concludes with a review of possible future developments, indicating the areas of research and product development required to maximise the potential of the only non-toxic, non-flammable, non-ozone-depleting, non-global-warming refrigerant available for Rankine cycle vapour compression systems in the 21st century. [Copyright &y& Elsevier]

Abstract: The aim of this paper is the detailed analysis of different well-known thermodynamic efficiencies usually used to characterize hermetic compressors. Attention is focussed on the volumetric efficiency, the isentropic efficiency, and the combined mechanical–electrical efficiency. A procedure is presented to detach these efficiencies into their main components (physical sub-processes) to get deeper insight on the overall behavior. The volumetric efficiency is split into partial efficiencies related to pressure drop and heat transfer effects, supercharging effects, superdischarging effects, leakages, etc. The isentropic efficiency is detached using two different points of view: the work associated to the individual sub-processes (compression, discharge, expansion, suction), and the work associated to the underpressures, overpressures, and between the inlet and outlet mean compressor pressures. Finally, the combined mechanical–electrical efficiency is related to the heat transfer losses/gains, and to the exergy transfers and exergy destroyed. Even though some of the concepts introduced in the paper can be applied to different kinds of compressors, the discussion is specially focussed on hermetic reciprocating compressors. An advanced simulation model developed by the authors has been used to generate data to illustrate the possibilities of the detailed thermodynamic characterization proposed. The criteria developed are useful tools for comparison purposes, to characterize compressors, and to assist designers during the optimization process. [Copyright &y& Elsevier]

Copyright of Gériatrie et Psychologie Neuropsychiatrie du Vieillissement is the property of John Libbey Eurotext Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)