bluuebunny/crossref_metadata_2025 huggingface dataset:
Deinstitutionalization: An Appraisal of Reform
Authors: Mechanic David , Rochefort David A.
Published: July 2003

The number of inpatients in US public mental hospitals declined from 559,000 in 1955 to approximately 110,000 at present. Reductions resulted from release or transfer of long-term inpatients and from entrance barriers to new admissions. The timing and pace of deinstitutionalization substantially varied by state, but three quarters of the national reduction followed the expansion of welfare programs in the middle 1960s. The establishment of community care alternatives was highly inadequate, leaving many severely and persistently mentally ill people without essential services. Problems of care were exacerbated by the contraction of welfare programs in the 1980s, which resulted in serious neglect and homelessness. Plagued by underfinancing and fragmentation of care, new strategies in developing mental health care systems include capitation, case-management approaches, and the development of strong local mental health authorities.
The US Labor Movement: Its Development and Impact on Social Inequality and Politics
Authors: Cornfield Daniel B.
Published: July 2003

The proliferation of research on the US labor movement has created opportunities for the development of theory on labor action. Such theory would account for variations in the development, structure, ideology, goals, functions, social composition, and societal impact of labor unions and, more generally, the labor movement. This review of recent sociological research focuses on two sets of enduring questions to which this research has been addressed. The first concerns the development of the U. S. labor movement—that is, its connection to industrialization; its internal organizational and ideological development; and worker predispositions to unionize and conduct strikes. The second pertains to the socioeconomic and political impact of the U.S. labor movement—i. e. its impact on worker livelihoods and life chances and social inequality, as well as its universalizing effects on the determinants of inequality; and, its impact on working class political participation and the shaping of social policy. This review concludes with suggestions for redirecting research in order to realize the growing opportunities for developing theory on labor action.
Comparative Intergenerational Stratification Research: Three Generations and Beyond
Authors: Ganzeboom Harry B. G. , Treiman Donald J. , Ultee Wout C.
Published: July 2003

In this article we review 40 years of cross-national comparative research on the intergenerational transmission of socioeconomic advantage, with particular attention to developments over the past 15 years—that is, since the transition between (what have become known as) the second and third generations of social stratification and mobility research. We identify the generations by a set of core studies and categorize them with respect to data collection, measurement, analytical models, research problems, main hypotheses, and substantive results. We go on to discuss a number of new topics and approaches that have gained prominence in the research agenda in the last decade. We conclude that the field has progressed considerably with respect to data collection and measurement; that shifts across generations with respect to data analytic and modelling strategies do not unambiguously represent advances; and that with respect to problem development and theory formulation the field has become excessively narrow.
Ethnic Minorities and Mental Health
Authors: Vega William A. , Rumbaut Rubén G.
Published: July 2003

The sociological study of the mental health of racial-ethnic minorities addresses issues of core theoretical and empirical concern to the discipline. This review summarizes current knowledge about minority mental health and identifies conceptual and methodological problems that continue to confront research in this field. First, a critique is presented of epidemiological approaches to the definition and measurement of mental health in general, and minority mental health in particular, induding an overview of the most frequently used symptom scales and diagnostic protocols. Next, the most important research studies conducted over the past two decades are summarized and discussed, and comparisons of prevalence rates and correlates of depressive symptomatology among Black, Hispanic, Asian, and American Indian ethnic groups are provided. Following the overview of descriptive epidemiological findings, some key analytic issues surrounding the study of stress, adaptation and minority mental health are considered . Finally, we propose various recommendations for future research.
The Diversity of Ethnomethodology
Authors: Maynard Douglas W. , Clayman Steven E.
Published: July 2003

Our purpose is to review the enormous range of ethnomethodological research from the past three decades. Periodically, scholars have produced review articles, monographs, and position papers that usually promote or critique the work of a particular ethnomethodological subfield. Also, textbook and other accounts of ethnomethodology sometimes impose a homogeneity on the field that neglects the various theoretical and methodological strands. We attempt to articulate the diversity each of the subfields represents, to clarify distinctions between them, and to demonstrate assumptions they share. The areas we discuss include theory, phenomenology, cognition, conversation analysis, research in institutional settings, studies of science, and applied research. While debates about proper topics and methods of research will no doubt continue, underneath such debates are a shared orientation to an extant, achieved orderliness in everyday activities and a commitment to discovering organizational features of direct interaction.
Sport and Society
Authors: Frey James H. , Eitzen D. Stanley
Published: July 2003

Sport is a very prominent social institution in almost every society because it combines the characteristics found in any institution with a unique appeal only duplicated by, perhaps, religion. The functional, conflict, and cultural studies perspectives are reviewed, with additional discussion on how sport relates to the processes of socialization and social change. The latter focusses on the evolution of sport from a playful, participation-oriented activity to one that resembles a corporate form guided by the principles of commercialism and entertainment. The role of sport in international relations and national development dramatizes the political meaning of sport to many societies. While sport may be integrative at the higher political levels, it has not been so at the interpersonal levels of gender and race. The inequality that characterizes society’s relations of gender and race is found in sport as well. The sociology of sport will be able to shed more light on all of these issues when theory informs more of the research in this subfield.
The Logic of Macrosociology
Authors: Hawley Amos H.
Published: July 2003

Amos H. Hawley received his AB degree from the University of Cincinnati in 1936, and his PhD from the University of Michigan in 1941. He taught at the University of Michigan from 1941 to 1966, serving as chair of the department from 1951 to 1961. During that period he also served at various times as demographic advisor to the government of the Philippines, the Netherland Antilles, Thailand, and Malaysia. From 1966 to 1976 he was a professor of sociology at the University of North Carolina, and Kenan Professor there from 1971 to 1976. Professor Hawley is a Fellow of the American Academy of Arts and Sciences; he was president of the Population Association of America in 1971 and of the American Sociological Association in 1978. He holds a Litt. D. from the University of Cincinnati and has been the recipient of the Lynd Award from the Urban and Community Sociological Section of the ASA and of the Award for Human Ecology Contributions from Cornell University. Professor Hawley is the author of 150 papers and books.
Contemporary Research on Social Democracy
Authors: Esping-Andersen Gosta , van Kersbergen Kees
Published: July 2003

This review examines the comparative, empirical literature that concerns the impact of social democracy on welfare state development and on economic performance. The theoretical basis of this research lies in reformist social democratic ideology which, in turn, is given substantial empirical confirmation in the sense that the balance of political power influences outcomes. The case against traditional modernization theory and other critiques is found to be strong, especially when the social democratic effect combines strong left parties with trade unions. The credibility of the social democratic model is particularly strong if we consider its consistent validation in cross-sectional as well as time-series analyses. It is, however, doubtful whether the “social democratic” thesis is applicable outside the framework of the advanced industrial democracies.
The Concept of Family Adaptive Strategies
Authors: Moen Phyllis , Wethington Elaine
Published: July 2003

Is “family adaptive strategy” a useful concept? Does use of this concept link actions of individual families with macro-level social change? This chapter examines the concept of family adaptive strategies, noting that it is an intuitively appealing metaphor for family response to structural barriers and stressful events. It has been used principally as a sensitizing device, describing both macro-level and micro-level trends and patterns of behavior. But good examples of empirical investigations of family strategies are difficult to find. What we mean by a good example is one that uses the family adaptive strategy concept as an explanatory process. Three studies, by Elder (1974), Tilly & Scott (1978), and Hareven (1982b), do fruitfully draw on family strategies of adaptation using concrete measures of this hypothetical concept. We discuss various methodological issues related to this concept: the level of analysis, the unit of analysis, and problems of operationalization. In addition to these methodoological problems, there are also conceptual difficulties: what exactly is and is not a “strategy,” whether families themselves view their actions as strategies or whether this label is based on researchers' analysis and interpretation, and whether strategies can be treated simultaneously as a cause and an effect. Several theoretical models serve to locate family strategies of adaptation. A structural approach emphasizes the ways that larger social structural forces constrain the repertoire of available adaptations. A rational choice approach underscores the role of choice, within the confines of structural constraints, in an effort to maximize family well being. And a life course approach points to the importance of historical time, life stage, and context in delimiting both family problems and the possible strategies to deal with them.
Commitment to Work and Family
Authors: Bielby D. D.
Published: July 2003

Demographic change and behavioral shifts in employment and household arrangements have caused scholars and social critics to question the nature of individuals’ involvement with work and family. Interpreting the cultural meaning of those behavioral changes requires the study of individual commitment per se. This chapter reviews research on commitment to work and family by examining issues of definition, measurement, and specification of the concept of commitment, by assessing theoretical developments in the study of linkages between work and family, and by reviewing research that examines the relationship of work and family to gender, the life course, social origin, and race. The interrelationship between work and family commitment is examined, and issues to be resolved in future research are discussed.
Population Aging and Social Policy
Authors: Uhlenberg Peter
Published: July 2003

As the life course currently is structured, old age is socially defined as a stage of life beginning in the early sixties, in which retirement from work and many other social responsibilities is expected. Few incentives exist for older persons to make productive contributions to the society, and obstacles to their engagement in productive activities exist. Consequently, large transfers from the working population to the retired are required, and potential contributions of the elderly to societal well-being are lost. Further, adult children often face a long period of being responsible for their aging dependent parents. Changes occurring in the older population challenge this existing arrangement. Not only is the ratio of the older to younger adults increasing, but also an increasing proportion of adults entering old age have the ability to make significant contributions (i.e. they are well educated, healthy, economically secure, and politically astute). Concern over this growing mismatch between older people's abilities and the roles they are expected to fill leads to a discussion of social policy. How might social policy increase the productivity of the elderly and/or reduce the burden of supporting a growing dependent older population. Three major categories of policies responsive to this question are considered. The outcome of these policy debates will significantly shape the future of aging in the United States.
Class Formation in Nineteenth-Century America: The Case of the Middle Class
Authors: Archer Melanie , Blau Judith R.
Published: July 2003

This review assesses sociological and historical research relevant to the emergence and consolidation of the American middle class in the nineteenth century. On the one hand, macrosociological theories have relied on a two-class model which renders the middle class a residual social category. Yet, on the other hand, community studies of the “new” social history—while they have opened up new avenues of inquiry into the complex social processes underlying middle class formation—have tended to focus on particular decades of the nineteenth century, leading to a fragmented view of the occupational composition of the middle class. Distinct literatures have developed around the study of particular occupational strata: artisans, small capitalists, white-collar wage earners, and the petite bourgeoisie. We argue here that different occupational groups overlap in time and represent a heterogeneous and historically shifting middle class rather than distinct entities. The argument for the integrity of a distinct middle class also rests on an understanding of the development of urban institutions and the cultural expressions of middle class lifestyles and behavior. The expansion of this middle class, however, was closely linked to a growing economy and increasing equality of opportunity. We speculate that the reversal of these conditions, evident from the 1970s, may undermine the well-being of the middle class and its correlative social values, notably tolerance and civility.
The Situational Analysis of Crime and Deviance
Authors: Birkbeck Christopher , LaFree Gary
Published: July 2003

In the late 1940s Sutherland proposed that explanations of deviance and crime are either situational or dispositional, and that of the two, situational explanations might be the more important. Nonetheless, with a few notable exceptions, for the next four decades sociologists focused on dispositional theories to the near total exclusion of situational variables. However, an increasing awareness of the theoretical limitations of strategies based only on dispositions has begun to encourage researchers to reconsider situational explanations. Most of the research that explicitly examines situational dynamics in producing crime has originated in experimental psychology, symbolic interactionism, or opportunity theories. Experimental research has helped to identify the situational correlates of crime and deviance, but lacks a theoretical framework for organizing its disparate empirical findings. Symbolic interaction research has emphasized the actor's role in defining and interpreting situations but thus far has not provided a theoretical link between motivation, opportunity, and crime. Opportunity theorists, especially those studying victimization, have made the most progress toward developing a situational theory of crime, but their emphasis on the victim rather than the offender imposes serious theoretical and methodological limitations.
The Sociology of Work and Occupations
Authors: Abbott Andrew
Published: July 2003

I review recent studies of work and occupations. Most of this work proceeds at the individual level, studying individual characteristics of workers, qualities of the work experience, and, to a lesser extent, stages of the work experience. Structural analysis is less common and often treats structural phenomena as aggregates rather than emergents, except in the area of labor relations. A substantial literature—probably a third of the total—examines particular occupations. In general the literature is divided into two “sides”—one focused on gender, inequality, and career/life cycle issues, the other on unions, and industrial and labor relations. Between these are smaller foci on theoretical issues and on general structures of work. I conclude that with the possible exceptions of Marxism and the study of professions, subfields of work and occupations lack the synthetic theory that would enable synthesis of empirical results. I also consider the twofold role of politicization in the area: the positive role of driving empirical investigation of new areas, the negative one of taking its own politics as unproblematic
Macrocomparative Research Methods
Authors: Bollen Kenneth A. , Entwisle Barbara , Alderson Arthur S.
Published: July 2003

Macrocomparative research has a broad reach within the discipline. We review recent books and articles engaging in comparison, either of nations or of structures and processes within two or more nations. We focus on how macrocomparative sociologists address the threats to validity which surround sample selection, research design, and data and measurement. Nearly all the studies we investigate have explanation as a goal. A major threat to many studies (almost a third) is the failure to apply any method of control. Most authors wish to draw general conclusions, but problems of sampling raise questions about their ability to do so. Researchers agree that measurement is problematic. However, issues surrounding measurement are largely neglected. We describe these and more specific empirical findings regarding the practice of macrocomparative research.
Social Organization and Risk: Some Current Controversies
Authors: Clarke Lee , Short James F.
Published: July 2003

The sociology of risk is fast becoming a recognized field of theory and research. We consider and evaluate the following key issues, debates, and theories in this emerging field: (i) The argument over whether technological disasters are different from natural disasters, (ii) the contributions of social constructionism to theories of risk, (iii) how recent work on trust and fairness can reorient scholarship on risk perception, (iv) the theory of human error, and why organizational, institutional, and cultural factors are more important, (v) the arguments about organizations that appear to be error-free (i.e. high reliability organizations), (vi) the paradox that we must rely on organizations for responding to disasters though organizations may be precisely the wrong social instruments for such response. Throughout we emphasize the role of organizations and institutional contexts in creating, assessing, and responding to risk.
Societal Taxonomies: Mapping the Social Universe
Authors: Lenski Gerhard
Published: July 2003

Taxonomies have played a much more important role in the development of the sciences than is generally recognized by sociologists. They have provided both a foundation for the formulation of basic theory and a spur to innovative research. This paper traces the development from ancient times to the present of efforts to create a taxonomy of human societies, the most basic and inclusive of all social systems. It concludes with a discussion of the question of whether there are compelling reasons for preferring any one of the various taxonomies that have been devised. Four principles for evaluating taxonomies are proposed and applied.
Women, Family and Class
Authors: Sorensen Annemette
Published: July 2003

The question of how to incorporate women in class analysis and stratification research has been the topic of heated controversy in recent decades. Much of the debate has been about the conventional approach to research on social mobility and class analysis that assumes the family to be the unit of stratification and the family’s class position to be determined independently of women’s work position. Those defending the conventional view can show that research on the empirical validity of the conventional view provides partial support for it, and that its use in previous empirical research probably has not resulted in serious misrepresentations. In this article, I review the literature on these issues. I summarize the criticism and defense of the conventional view and review research that examines its empirical adequacy. This is followed by a discussion of alternative approaches to the determination of the family’s class position.
Coresidence and Leaving Home: Young Adults and Their Parents
Authors: White Lynn
Published: July 2003

This review pulls together research on home leaving, home returning, parent-child coresidence, and the launching process and integrates it with theoretical perspectives related to the life course. Material is included from Australia, Canada, and Britain as well as the United States. Because the nuclear family form specifies that children leave the parental home when they marry and few married persons live with their parents, the focus is on relationships between unmarried children and their parents. The review concentrates on the young adult years while recognizing coresidence experiences over the life course. The nature of the link between residence patterns, family relationships, and dependence is an empirical question that, for the most part, has not been answered.
Between Rocky Democracies and Hard Markets: Dilemmas of the Double Transition
Authors: Centeno Miguel Angel
Published: July 2003

There is a growing realization in academic and policy circles that the double transition to democracy and the market may not be as simple or as easy as first imagined. Beginning with a discussion of the relationship between economic policy and regime type, this review emphasizes the problems associated with the uncertainty of the double transformation. It then suggests three mechanisms discussed in the literature as contributing to a more stable transition. Some authors have emphasized the importance of social and political contracts. Others contend that the transition must be imposed by the domination of a class or the state. A third group has focused on the rise of a new civil society and the need for some form of trust between the various groups. The review concludes with a call for more field level research and a greater emphasis on perceptions and expectations of change.
Sociobiology and Sociology
Authors: Nielsen François
Published: July 2003

Sociobiology is the study of the biological bases of behavior in the context of neo-Darwinian evolutionary theory. This review organizes the contribution of sociobiology to the understanding of human behavior around a small number of major theoretical articulations. These include identification of the gene as the basic unit of selection: the concept of inclusive fitness and the role of relatedness: models of reciprocal altruism and the concept of evolutionarily stable strategy (ESS): and the theory of optimal reproductive investment. Sociobiological and evolutionary thinking is expected to affect sociology in a number of areas including sex and gender roles: the theory of collective action: and the elaboration of a richer and more complex model of human nature.
The New Sociology of Knowledge
Authors: Swidler Ann , Arditi Jorge
Published: July 2003

The new sociology of knowledge examines how kinds of social organization make whole orderings of knowledge possible, rather than focussing on the differing social locations and interests of individuals or groups. The review begins with the effects on knowledge of the media through which it is preserved, organized, and transmitted. We then analyze collective memory, examining social conditions that shape how knowledge is transmitted through time. The review then examines how patterns of authority located in organizations shape both the content and structure of knowledge, looking at how authority affects the scope, generality, and authoritativeness of knowledge. We then review recent work on how social power, particularly that embodied in institutional practices, shapes knowledge. We examine how knowledge reinforces social hierarchies and how the boundaries and categories of systems of knowledge are constituted. Looking at power, gender, and knowledge, we discuss new versions of the standpoint theories that characterized the traditional sociology of knowledge. Finally, we briefly review recent work on informal knowledge.
Multilevel Models: Methods and Substance
Authors: DiPrete Thomas A. , Forristal Jerry D.
Published: July 2003

This paper reviews recent developments in the application of multilevel models to substantive problems in sociology. There is no single multilevel model in sociology, but rather a set of more or less closely related approaches for exploring the link between the macro and micro levels of social phenomena. Methodological developments of the last ten years are discussed and contrasted with older methods. Illustrative examples of how multilevel analysis has contributed to sociological knowledge are provided for several areas of the discipline, including demography, education, stratification, and criminology. Cautions in the use of these models for empirical research are discussed, along with possible further developments.
Sequence Analysis: New Methods for Old Ideas
Authors: Abbott Andrew
Published: July 2003

A wide variety of work in social science concerns sequences of events or phenomena. This essay reviews concepts of sequence and methods for analyzing sequences. After a brief definitional discussion, I consider sequence literatures from various areas. I then discuss recent methodologies for sequence analysis. I review stepwise approaches like Markovian and event history analysis as well as whole sequence approaches resting on new developments in biology and other fields.
Genetic Diversity as an Objective in Multi-Objective Evolutionary Algorithms
Authors: Toffolo Andrea , Benini Ernesto
Published: July 2003

A key feature of an efficient and reliable multi-objective evolutionary algorithm is the ability to maintain genetic diversity within a population of solutions. In this paper, we present a new diversity-preserving mechanism, the Genetic Diversity Evaluation Method (GeDEM), which considers a distance-based measure of genetic diversity as a real objective in fitness assignment. This provides a dual selection pressure towards the exploitation of current non-dominated solutions and the exploration of the search space. We also introduce a new multi-objective evolutionary algorithm, the Genetic Diversity Evolutionary Algorithm (GDEA), strictly designed around GeDEM and then we compare it with other state-of-the-art algorithms on a well-established suite of test problems. Experimental results clearly indicate that the performance of GDEA is top-level.
Globalization and the Governance of Biotechnology
Authors: Newell Peter
Published: July 2003

This article focuses on the disjuncture between the regulatory problems generated by the rapid development of, and subsequent trade in crop “genetically modified organisms” (GMOs), and the ability of existing international governance mechanisms to manage the associated human and ecological risks. The article assesses how the globalization of economic activity is reconfiguring patterns of production, investment, regulation and political authority as they relate to the governance of biotechnology.

It is argued that our collective ability to provide social and environmental protection from GMO-related risks must be understood in relation to the global economic processes which create the technology and influence the policy processes set up to manage it. This requires an enhanced understanding of the reciprocal relationships between intra- and inter-firm decision-making and global decision-making.
Private Environmental Governance and International Relations: Exploring the Links
Authors: Falkner Robert
Published: July 2003

This article discusses private environmental governance at the global level. It is widely acknowledged that corporations play an increasing role in global environmental politics, not only as lobbyists in international negotiations or agents of implementation, but also as actors creating private institutional arrangements that perform environmental governance functions. The rise of such private forms of global governance raises a number of questions for the study of global environmental politics: How does private governance interact with state-centric governance? In what ways are the roles/capacities of states and nonstate actors affected by private governance? Does the rise of private governance signify a shift in the ideological underpinnings of global environmental governance? This article explores these questions, seeking a better understanding of the significance of private environmental governance for International Relations.
The 2000 New Hampshire Democratic Primary and Network News
Authors: Farnsworth Stephen J. , Lichter S. Robert
Published: July 2003

Content-coded network newscasts were used to examine the relationship between news coverage and the daily New Hampshire poll standings of Al Gore and Bill Bradley, the two major Democratic presidential candidates, in the weeks before the primary. The study found powerful network news effects, particularly with respect to “horse race” reports on which candidate gained and fell back but also with respect to televised evaluations of more substantive matters such as character and issue positions. The results cast doubt on claims by those who support New Hampshire’s status as the nation’s first primary because the state is thought to differ from the media-dominated electoral contests found elsewhere in American politics.
Voting From the Bench
Authors: Jones Clifford A.
Published: July 2003

This work generally describes media coverage of postelection litigation in Florida following the 2000 presidential election. Examining some of the ways the broadcast media covered certain legal issues arising from the litigation, the research concentrates on legal issues surrounding the infamous Palm Beach County “butterfly ballot” and equal protection litigation in the federal courts. The data are drawn from content analysis of evening news broadcast of the three major television networks, NBC, CBS, and ABC, from November 7 to December 13, 2000, the day following the final decision of the Supreme Court of the United States. The research concludes that the broadcast media substantially overlooked the equal protection issue until the very end of the postelection campaign and thus failed to educate the public on what turned out to be the most decisive and important issue in the Supreme Court’s decision to halt the manual recounts in Florida.
From the Primary to the General Election
Authors: Banwart Mary Christine , Bystrom Dianne G. , Robertson Terry
Published: July 2003

Prior research on the media’s portrayal of female candidates in comparison to male candidates has indicated that differences do exist, although most studies have focused on general election races of senate candidates. This study analyzed the media’s portrayal of candidates in mixed-gender gubernatorial and U.S. Senate races through a comparison of primary coverage to general election coverage in 2000. The study relied on content analyses of more than 1,200 articles from major newspapers to understand how female and male candidates might be framed differently when running for their party’s nomination as opposed to during the general election. The findings suggest that although the coverage from the primaries to the general election was relatively consistent across most categories of analysis, female candidates continue to face some stereotypical biases in the news coverage of their campaigns.
Optimization of an air-cooled hybrid gas turbine cycle (Brayton/Ericsson)
Authors: Frost T. H. , anderson A , Agnew B , Potts I
Published: July 2003

The performance of a Brayson cycle, a hybrid gas turbine cycle, has been examined to establish the effect of air cooling and heat exchanger effectiveness on the cycle efficiency and specific power. The air-cooled heat exchanger was optimized to produce the maximum net efficiency for the specified minimum cycle temperature. The cycle performance was shown to be adversely influenced by the air cooling as it reduced both the specific power and efficiency. The heat exchanger effectiveness was shown to have a secondary impact on the performance parameters. An additional optimization of the heat exchanger at minimum volume is also presented to act as a benchmark against which the performance of the heat exchanger in the optimized cycle can be compared.
Thermodynamic design of a reciprocating Joule cycle engine
Authors: Bell M. A. , Partridge T
Published: July 2003

This paper describes a first-order model of a Reciprocating Joule Cycle (RJC) engine, which is then used to investigate its thermodynamic design with a view to establishing its optimum performance for a given set of operating conditions. The RJC engine is essentially the reciprocating counterpart of the gas turbine. Its performance is determined by the characteristics of a reciprocating, as opposed to a rotodynamic, compressor and expander. The thermodynamic cycle investigated incorporates regenerative heat exchange. An air standard model modified to include the effects of friction, combustion, clearance volumes, leakage and pressure drops, shows that the performance of the RJC engine is strongly dependent on its operating pressure ratio and dependent to a much lesser extent on its expander to compressor swept volume ratio. It is shown that a thermal efficiency approaching 50 per cent might be achievable under realistic conditions. Using a maximum operating temperature of 1300 K, optimum thermal efficiency with a high specific work output occurs when its nominal operating pressure ratio is in the range 6 to 8, and its expander to compressor swept volume ratio is in the range 2 to 3. The RJC engine is proposed as a suitable prime mover for micro-CHP systems, small stand-alone power units, or hybrid vehicles.
Combined cycle dynamics
Authors: Mansour F. M. , Abdul Aziz A. M. , Abdel-Ghany S. M. , El-shaer H. M.
Published: July 2003

A mathematical model describing the dynamic behaviour of each major component of the combined cycle is presented. The formulae are deduced from continuity, momentum, energy, and state equations. Partial differential equations (PDEs) are discretized to algebraic equations by using the implicit backward-central finite difference scheme and then solved by iteration. Explicit-Euler's integration method is applied to other differential equations (DEs). A multi-element control system is implemented to investigate its effect on the combined cycle's dynamic response. The simulation results are compared with the design and steady-state operational data of the unit number 4 in Cairo South Combined Cycle Power Plant, showing good agreement. The dynamic results prove the effectiveness of the multi-element control strategy to control the combined cycle plant with fast settling time, neglected steady-state error, and moderate overshoot or undershoot while assuring a stable operation under sudden changes of load.
Global stability and control analysis of axial compressor stall and surge phenomena using bifurcation methods
Authors: Ananthkrishnan N , Vaidya U. G. , Walimbe V. W.
Published: July 2003

Active controllers that allow the compressor to operate safely at its peak pressure rise point by preventing surge and controlling entry into rotating stall need to be globally stabilizing. Bifurcation methods have emerged as a useful tool for the analysis of global stability and control of nonlinear dynamical systems such as the axial compressor. In this paper we show how bifurcation analysis can be used effectively to obtain answers to questions of global stability of the compressor dynamics. Since the bifurcation method does not directly provide information on transient behaviour, we demonstrate how bifurcation results need to be carefully interpreted to be of use when dealing with practical systems. We then present a novel nonlinear bifurcation-based stall/surge controller that is globally stabilizing. With such a controller, it becomes possible to avoid surge entirely and to prevent abrupt entry into rotating stall. The controller also eliminates the hysteresis between entry into and recovery from a rotating stall, and maintains system stability under all perturbations, small and large.
Calculations of three-dimensional viscous flow in a multiblade centrifugal fan by modelling blade forces
Authors: Seo S-J , Kim K-Y , Kang S-H
Published: July 2003

A numerical study is presented for Reynolds-averaged Navier-Stokes analysis of three-dimensional turbulent flows in a multiblade centrifugal fan. Present work aims at development of a relatively simple analysis method for these complex flows. A mathematical model of impeller forces is obtained from the integral analysis of the flow through the impeller. A finite volume method for discretization of governing equations and a standard k-ɛ model as turbulence closure are employed. For the validation of the mathematical model, the computational results for velocity components, static pressure, and flow angles at the exit of the impeller were compared with experimental data. The comparisons show generally good agreement, especially at higher flow coefficients.
Numerical investigation of flowing processes for regenerators of transport gas turbine units
Authors: Yoo I. S. , Kovalevski V. P. , Kim S. Y.
Published: July 2003

A distributed nonlinear mathematical model for investigation of regenerative heat exchangers of both rotating-matrix and fixed-matrix is described. A noniterative numerical integration scheme for a conjugate unsteady heat exchange problem of one-dimensional flow and two-dimensional wall conduction is developed. An example study of a regenerative heat exchanger with a rotary ceramic matrix is presented. The range of optimum rotation rates supplying the highest calorific efficiency to the regenerator is determined.
Studies on natural convection-induced flow and thermal behaviour inside electronic equipment cabinet model
Authors: Ishizuka M , Kitamura Y
Published: July 2003

In the present work, an important basic flow phenomenon, natural convection-induced flow, is studied numerically. Three-dimensional Navier-Stokes equations along with the energy equation are solved based on the finite difference method. A generalized coordinate system is used so that sufficient grid resolution could be achieved in the body surface boundary layer region. The results of calculation showed a satisfactory agreement with the measured data and led to a good understanding of the overall flow and thermal behaviour inside an electronic equipment cabinet model, which is very difficult, if not impossible, to gather by experiment.
Liquid‐crystalline copolyester/clay nanocomposites
Authors: Zhang Guangli , Jiang Cuihong , Su Chenyu , Zhang Hongzhi
Published: July 2003

A series of novel polymer–clay nanocomposites, that is, liquid‐crystalline copolyester/montmorillonite (MMT) nanocomposites, were synthesized by the intercalation polycondensation of terephthalic acid, p‐acetoxy benzoic acid, and 1,2‐diacetoxy benzene in the presence of different organically modified montmorillonites (OMt's). The OMt's were prepared by the ion exchange of MMT with octadecylamine hydrochloride, p‐aminobenzoic acid hydrochloride, or lysine hydrochloride. X‐ray diffraction and transmission electron microscopy studies indicated that the inorganic cations in the MMT interlayers were already exchanged by organic onium ions and that the OMt intercalated with p‐aminobenzoic acid or lysine was good for obtaining more delaminated clay nanocomposites. The glass‐transition temperature and modulus of the nanocomposites increased compared with those of the pure polymer, whereas the isotropic temperature decreased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3155–3159, 2003
Adsorption mechanism of surfactants on nonwoven fabrics
Authors: Cai Bing , Zheng Qing‐Kang , Li Rui‐Xia , Wu Da‐Cheng
Published: July 2003

For improved surface properties, nonwoven fabrics of polypropylene and poly(ethylene terephthalate) were treated with several kinds of surfactants, including anionic, cationic, and nonionic types. The adsorption isotherms of the anionic, cationic, and nonionic surfactants on the nonwoven fabrics were different. The adsorption isotherm of the cationic surfactant (dodecyl dimethylbenzyl/ammonium chloride) exhibited a maximum. The adsorption isotherm of the anionic surfactant (sodium dodecylbenzene sulfonate) was in the shape of the fifth Brunauer adsorption isotherm, and that of the nonionic surfactant (alkylphenol/ethylene oxide condensate) was similar to the fourth Brunauer adsorption isotherm. The time of the adsorption equilibrium was constant for the same types of adsorbate and adsorbent, and it was not related to the initial concentration. The specific surface resistance of the nonwoven fabrics decreased substantially after the adsorption of ionic surfactants. The nonwoven fabrics with the surfactants were characterized with scanning electron microscopy and X‐ray photoelectron spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3210–3215, 2003
Carboxymethylation of Cassia tora gum
Authors: Sharma Brij Raj , Kumar Vineet , Soni P. L. , Sharma Pradeep
Published: July 2003

The preparation of carboxymethyl (CM)–Cassia tora gum (CTG) with monochloroacetic acid and sodium hydroxide was investigated under different reaction conditions. The carboxymethylation reaction was studied with respect to the degree of substitution of CM–CTG. The variables studied were the concentration of reactants, methanol–water ratio (solvent), reaction time, and reaction temperature. Carboxymethylation of CTG increased its solubility in cold water and the stability of its paste to microorganisms. Regardless of the degree of substitution of these products, their aqueous solutions were characterized by non‐Newtonian pseudoplastic behavior. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3216–3219, 2003
A kinetics model for interphase formation in thermosetting matrix composites
Authors: Yang F. , Pitchumani R.
Published: July 2003

During the cure of thermosetting polymer composites, the presence of reinforcing fibers significantly alters the resin composition in the vicinity of the fiber surface via several microscale processes, forming an interphase region with different chemical and physical properties from the bulk resin. The interphase composition is an important parameter that determines the micromechanical properties of the composite. Interphase development during processing is a result of the mass‐transport processes of adsorption, desorption, and diffusion near the fiber surface, which are accompanied by simultaneous cure reactions between the resin components. Due to complexities of the molecular‐level mechanisms near the fiber surface, few studies have been carried out on the prediction of the interphase evolution as function of the process parameters. To address this void, a kinetics model was developed in this study to describe the coupled mass‐transfer and reaction processes leading to interphase formation. The parameters of the model were determined for an aluminum fiber/diglycidyl ether of bisphenol‐A/bis(p‐aminocyclohexyl)methane resin system from available experimental data in the literature. Parametric studies are presented to show the effects of different governing mechanisms on the formation of the interphase region for a general fiber–resin system. The interphase structure obtained from the model may be used as input data for the prediction of the overall composite properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3220–3236, 2003
Deformation and fracture of Mg(OH)2‐filled polyolefin composites under tensile stress
Authors: Zhu Song , Zhang Yong , Zhang Yinxi
Published: July 2003

The tensile behavior of high‐density polyethylene (HDPE), polypropylene (PP), and linear low‐density polyethylene composites containing a titanate coupling agent and silicone‐oil‐treated magnesium hydroxide [Mg(OH)2] was studied. The increase in the extent of the ultimate elongation of the composites was affected by the yield stress and the strain‐hardening tendency of the polymer matrix in the composites. Ethylene–propylene–diene rubber and octane–ethylene copolymer were introduced to adjust the yield stress of PP and HDPE. Although the ultimate elongation of PP/elastomer and HDPE/elastomer blends was higher than that of virgin PP or HDPE, the ultimate elongation of the filled composites dropped at a high content of Mg(OH)2. Scanning electron microscopy showed that the difference in the uniformity of the interface exfoliation decreased with the yield stress of the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3248–3255, 2003
Differential scanning calorimetry studies on high‐ and low‐density annealed and irradiated polyethylenes: Influence of aging
Authors: Vallés‐Lluch A. , Contat‐Rodrigo L. , Ribes‐Greus A.
Published: July 2003

The effect of γ‐radiation, followed by 10 years storage at ambient conditions, on the thermal behavior of different types of high‐ and low‐density commercial polyethylenes was studied. First, samples were annealed to improve the crystalline content. Next, they were irradiated, after which fusion endotherms, melting temperatures, crystallinity indices, and lamellar thicknesses were obtained by differential scanning calorimetry (DSC). The change in the thermal parameters for the first and second meltings were related to the absorbed doses. Afterward, the samples were stored at ambient conditions for 10 years and then scanned again by DSC to assess the influence of aging on previously irradiated samples. The results showed that the changes on the morphological structure undergone by the samples with the storage time were highly dependent on the polyethylene type and the absorbed radiation dose. The high‐density polyethylene was the most sensitive to radiation and storage, whereas the low‐density polyethylene with the lowest molecular weight and the highest degree of branching was the least affected. In general, the changes observed during irradiation can be explained in terms of an increase of imperfections and chain scissions. The storage can be understood as a slow crystallization process at low radiation doses, and as a decrease of the crystalline structure at high doses. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3260–3271, 2003