bluuebunny/crossref_metadata_2025 huggingface dataset:
Reflection of Family Transference in Group Psychotherapy for Preadolescents
Authors: Hamori Eszter , Hódi Ágnes
Published: March 2007

This is a detailed account of an 18-month course of psychoanalytically oriented psychotherapy for preadolescent children. The authors show how developmental aspects of early adolescence have to be understood in order to contain and work with the group's preoccupations. Intensely ambivalent feelings about separation and independence are expressed and enacted in the group. Transferential and realistic aspects of the group's relationship to the therapists are highlighted and the therapist's countertransference is discussed. Effective supervision is seen to produce development in the group's functioning.
Identity and the Belonging Group: Personal Integrity in the Changing Organization
Authors: Prodgers Alan
Published: March 2007

Our sense of self and its integrity is not a given, but is dependent on the groups to which we belong. The rapidly changing nature of work organizations since the Second World War has had a profound impact on our identity. This is explored through a number of case vignettes.
Quality control and validation boundaries in a triple helix of university-industry-government: “Mode 2” and the future of university research
Authors: Fujigaki Yuko , Leydesdorff Loet
Published: March 2007

How is quality control organized in the new “Mode-2” production of scientific knowledge? When institutional boundaries are increasingly blurred in a triple helix of university-industry-government relations, criteria for quality control in the production of scientific knowledge can be expected to change at the interfaces. The categorization in terms of two modes of knowledge production was introduced by Gibbons et al. (1994) to describe changes in the networks of scientific communications (funding patterns, research configurations, styles of knowledge management, etc.). These changes were specified mainly as institutional parameters in order to deal with the subjects of R&D management and S&T policies, that is, ex ante (Spiegel-Rösing, 1973; Van den Daele et al., 1979). We focus on the “validation boundaries” emerging from the differences between Mode 1 and Mode 2; that is, on the criteria for quality control that can analytically and reflexively be brought to the fore ex post. The shift from an institutional frame of reference to the dynamics of communications enables us to clarify several problems in the discussion of the future of university research.
Gender inequality and paradigms in the social sciences
Authors: Andersen Heine
Published: March 2007

The article is based on a survey of 788 Danish researchers, mainly from the social sciences, and analyses differences between female and male researchers concerning cognitive styles and cognitive convictions. Sandra Harding's portrait of modern science as androcentric and characterized by a set of gender-related dualisms is taken as a point of departure, and the results by and large show gender differences which can be related to this picture. Male researchers give more importance to methodological ideals taken from natural science, objectivity, mathematical methods, rationality, universality and cumulative results, etc., than female researchers do. These differences are shown to be correlated with the degree of power orientation of research topics.
The Transverse Science and Technology Culture: Dynamics and Roles of Research-technology
Authors: Shinn Terry , Joerges Bernward
Published: March 2007

Science and technology are composed of several regimes of production, each having its own research axis and mode of diffusion - the disciplinary regime, transitory regime, utilitarian regime, and transverse regime. This article discusses research-technology, an example of the transverse regime of cognitive and artefact production. Research-technologists stand between science and engineering, between academia and enterprise. They design and build a special category of instrumentation (open-ended, multi-purpose generic instrumentation) and they operate out of an interstitial arena that lies between the usual poles of interest and organization - university, firms, the state, military etc. By virtue of their interstitial position and development of generic multi-audience devices, research-technologists exhibit a highly dynamic division of socio-cognitive labor. They sometimes engage in boundary crossings, in order to acquire data for instrument design or for purposes of instrument diffusion. Conversely, they sometimes close borders, protecting themselves from the exogenous pressures of short-term audience demand. One sees that selective boundary-crossing is not inconsistent with community closure! This article outlines the history of research-technology in Germany and the US, shows how the research-technology perspective differs from the new orthodoxy in the sociology of knowledge, and points to how a better grasp of the workings of the division of socio-cognitive labor may prove fruitful beyond the sociology of science and technology.
From self-reference to autology: how to operationalize a circular approach
Authors: Esposito Elena
Published: March 2007

One of the most innovative features of Niklas Luhmann's theory resides in its allegedly circular construction: it starts from the assumption that even a theory of society itself is but a part of the object (society) that it aims to explain. Hence the relevance and crucial position of the issue of self-description. Using observation theory and second-order cybernetics, the paper briefly examines the epistemological presuppositions that are the basis for this position. It then turns to one of the aspects of the theory that reveals most clearly the consequences of this circular approach: the study of communication as applied to the system of science.
Reason, interest and passion in the East European transitions
Authors: Elster Jon
Published: March 2007

The politics of transitions to democracy include both the forward-looking task of constitution-making and the backward-looking task of transitional justice. To study these processes and to explain their outcomes, one must among other things identify the motives of the political actors that are involved. Following the French moralists, the article tries to identify and assess the importance of interest, passion and reason as motives of the actors. The article also discusses the tendency for actors to misrepresent their motivations, and the frequent formation of alliances between actors animated by different motives that converge on specific policy issues.
The Civilizational Dimension in Sociological Analysis
Authors: Eisenstadt S. N.
Published: March 2007

The civilizational turn in sociological theory is best understood as an attempt to do full justice to the autonomy of culture (against all versions of structural-functional theory) without conceding the issue to cultural determinism. Civilizational formations are based on combinations of cultural visions of the world with regulative frameworks of social life, but the relationship between the two levels is open to conflicting interpretations and strategic uses of them. Axial age civilizations open up new structural and historical dimensions of interaction between cultural and social patterns, and are therefore central to the agenda of civilizational analysis. Among the later breakthroughs which draw on Axial sources, the emergence of modernity stands out as particularly important; the cultural and political program of modernity may be seen as a new and distinctive civilization, but it remains open to more or less formative influences from older civilizational legacies.
Perceiving the Pilbara: Finding the Key to the Country
Authors: Seddon George
Published: March 2007

The land and the people of the Pilbara in north-western Australia have been perceived, and the landscape conceptualized, used or abused (depending on one's perception), in a variety of ways through time. Differing perceptions have been reflected and modified by linguistic use, especially the metaphors applied, including the search for `a key to the country'; by conditions of observation, including the means of transport; by changing economic and utilitarian values; by images generated by painters and photographers; by the commodifications of the tourist industry and by scientific research, especially in anthropology, archaeology, geology and ecology. Changing perceptions of the Pilbara play a significant part, not only in Australia's economic performance, but also in its sense of global positioning. Yet awareness of the Pilbara itself by contemporary Australians lacks the intimacy that its indigenous inhabitants once had: it has been premature to remove the words `Terra Incognita' from much of the map.
Japanese `Capitalism' Revisited
Authors: Johnson Chalmers
Published: March 2007

Japan is the world's second most productive economy, but its economic system is intensely controversial. It differs from both the plan-rational systems of the communist world and the market-rational systems of the capitalist world in that it combines elements of both. This configuration directly challenges orthodox capitalist theory as advanced by the United States and the United Kingdom. During the 1990s, when Japan's economy slowed greatly and some other economies of East Asia were besieged by international capital flows, Japan's economy was singled out for a withering ideological critique. Nonetheless, what is wrong in Japan is not its economy but its status as a military satellite of the United States, which causes its political system to be ineffective in serving the country's economic interests.
Porous Connections: The Mediterranean and the Red Sea
Authors: Parker Grant
Published: March 2007

A close reading of the Periplus of the Erythraean Sea (1st century CE), an anonymous captain's manual written in everyday Greek, provides ways of thinking about broader questions concerning the connectedness of the Indian Ocean and the Mediterranean. It is located primarily in the Red Sea, an interstitial zone between the two large seas, and concerns long-distance networks of exchange between South Asia, the Arabian peninsula, the Horn of Africa, Alexandria, and beyond that the Mediterranean. Among the issues to emerge are the linear nature of spatial experience and the means by which commodities are mapped. A goal of the article is to identify ways in which to link the practice and representations of travel.
1968: from Co-determination to Co-worker. the Power of Language
Authors: Stråth Bo
Published: March 2007

The focus of this article is the deep transformation of labour markets and working life in the wake of `1968', where the class language culminated in slogans like co-determination, Mitbestimmung and autogestion, and in the development of new practices like sit-ins, work-ins, factory occupations and so on. The massive criticism expressed in the new language posed a major challenge not only to organized capital, but also for organized labour, i.e. the trade unions. However, the shop floor protests were quickly followed by the new neoliberal ideology emphasizing values like proximity and flexibility, and a growing role for the individual worker in a friendly relationship with the employer as opposed to the old class-based antagonism. The old Arbeiter became the Mitarbeiter, the worker became the co-worker. The article discusses the preconditions of this conceptual transformation.
Labor's Legal Mobilization
Authors: McCAMMON HOLLY J.
Published: March 2007

Whereas workers' use of the strike in workplace disputes has declined over the past decades, their legal mobilization—that is, the filing of unfair labor practice charges against employers—has risen. Little attention in labor sociology has been given to the circumstances in which workers turn to the law. Yet, within the union movement and in other social movements as well, legal mobilization is a commonly used strategy. The author develops and empirically tests a model of the circumstances in which workers use the law. A number of factors are found to influence this process, in particular, the “underlying activity” (that is, union elections) and various economic circumstances. Theoretical conclusions are drawn on the basis of these findings.
How does Collective Bargaining Affect the Gender Pay Gap?
Authors: ELVIRA MARTA M. , SAPORTA ISHAK
Published: March 2007

The authors study the effect of unionization on gender wage differentials for production workers in nine U.S. manufacturing industries. They find that the wage gap is significantly smaller in unionized establishments for six of the industries, even after controlling for occupation and establishment gender composition. But this union effect does not hold within three industries. The authors conclude that unionization generally reduces wage inequality between blue-collar men and women, but the effect might be contingent both on the overall proportion of women in an industry and on union characteristics. The authors discuss the implications of these findings for income inequality and union policies.
Adapting to Danger
Authors: Fitzpatrick John S.
Published: March 2007

The research was initiated to explore the effects of occupational danger upon an occupation's participants. From work relating to the disaster subculture concept, studies of occupational groups, and research regarding subcultures, it was hypothesized that participants in dangerous occupations adapt to the threats of their work environment by creating and sustaining a protective social mechanism which was named an "occupational subculture of danger." Using a grounded theory approach the article describes how social interaction in a threatening environment leads to the formation of a protective social structure which enables the miners to cope with their hazardous work conditions.
Work Experience and Work Involvement
Authors: Lorence Jon , Mortimer Jeylan T.
Published: March 2007

This panel study examines the interrelations of work experience and psychological involvement in work among male college graduates over a 10-year period. The data analysis provides substantial support for the "occupational socialization hypothesis"—that work experience and, particularly, work autonomy, stimulate work involvement over time. There was also evidence for the "occupational selection hypothesis"— that high work involvement, prior to labor force entry, induces work values which promote stability m the early career and facilitates the attainment of income and work autonomy.
Economic and Sociological Approaches to Professionalism
Authors: BEGUN JAMES W.
Published: March 2007

Comparing sociological and economic approaches to professionalism yields some insights into a more general theory of the origins and consequences of professionalism. In both sociology and economics, a similar debate distinguishes two competing theoretical approaches. The free market approach in economics is analogous to the power theory in sociology, and the free market approach contributes to explaining which occupations are successful in the political movement accompanying professionalization and to specifying the economic costs of professionalism. Analogous to the structural-functional approach in sociology is the “market failure” perspective in economics, which is rooted in the recognition that some services are delivered under conditions of informational asymmetry between producer and consumer. A general theory of professionalism in sociology should incorporate both the structural-functional and power approaches and should be informed by findings from economics.
Plant Closings and Control Over the Workplace
Authors: ZIPP JOHN F. , LANE KATHERINE E.
Published: March 2007

There is growing literature focusing on the effects of plant closings on displaced workers. Although the gist of this literature is that plant closings have substantial negative economic, social/psychological, and physical health effects on workers, this “social problems” approach, by not placing capital mobility in the larger politicaleconomic context, is far too restrictive. We contend that plant closings need to be seen as playing an important role in the struggle between labor and management for control in the workplace. We examine this notion by analyzing the 1980-1981 relocation of GM's Corvette plant from St. Louis to Bowling Green, Kentucky. By analyzing interviews with relocated workers and company and union officials, along with various company and union documents, we trace the role that this relocation had in restructuring labor-management relations. In our concluding section, we note the implications of this both for the study of plant closings and for the study of the workplace struggle between capital and labor.
Gender and the Household Division of Labor
Authors: McALLISTER IAN
Published: March 2007

Although substantial effort has been directed at explaining patterns of unpaid household labor, relatively little is known about the effects of household work on employment and their interrelationship in determining paid income. This article applies multivariate analysis to data collected in Australia in 1984 and 1985 to examine the effects of employment on household work. The results show that women in the full-time work force are most affected by household labor, while it has a lesser impact on women in part-time employment; for the latter, household duties would appear to determine their labor market participation. Household labor has more consequences for the weekly earnings of women in full-time work than for those in part-time work, and it also has consequences for the weekly earnings of men. Finally, a decomposition of effects shows that household labor is comparable in importance to occupational characteristics in explaining income differentials between men and women in the full-time work force.
Household, Work, and Labor Activism
Authors: CORNFIELD DANIEL B. , CAVALCANTI FILHO HILQUIAS B. , CHUN BANG JEE
Published: March 2007

With union-corporation competition for worker allegiances and declining union membership during the post-World War II era, unions have increasingly sought to replenish their sagging memberships from the growing ranks of women workers. Consequently, unions have entered into a competition with households for the allegiances of women workers, given the persistence of traditionalism in gender roles. This article addresses household constraints on individual activism in labor organizations by examining gender differences in the determinants of membership participation in the Tennessee State Employees Association. The results showed that women's participation is more constrained than men's by household responsibilities, suggesting that competition among institutions for individual allegiances contributes to the level of individual activism in a social movement organization.
Employee Attachment and Noncoercive Conditions of Work
Authors: MUELLER CHARLES W. , BOYER E. MARCIA , PRICE JAMES L. , IVERSON RODERICK D.
Published: March 2007

Recent sociological arguments have claimed that employee attachment in corporatist organizations is produced, not with direct coercive measures, but indirectly by employers controlling various structural conditions of work. It is argued that this also occurs in smaller organizations that do not exhibit internal labor markets nor other corporatist organization characteristics. Specifically, in smaller organizations that are structured more traditionally with the employer deciding work schedules, pay, distribution of profits, and so on, the features of employee social integration, autonomy/participation, and legitimacy of the authority structure are just as important as they are in the larger corporatist firms. This claim is generally supported with data on the job satisfaction, the organizational commitment, the intent to stay, and the turnover of dental hygienists working in dental offices that are controlled by the employer, the dentist. Work group integration and legitimacy-producting features were found to be especially important. In addition, job satisfaction, not organizational commitment (loyalty), was the crucial intervening variable in the causal process. These data indicate that certain basic conditions of work, such as social integration and legitimacy of the authority structure, are essential for employee attachment to form. The actual work structures that produce these conditions, however, can vary considerably.
The Impact of Comparable Worth on Earnings Inequality
Authors: FIGART DEBORAH M. , LAPIDUS JUNE
Published: March 2007

To investigate the relationship between earnings inequality and the gender-based wage differential, we estimated the correlation between wages and the percentage of women in three-digit occupations and eliminated this negative effect under a proposed comparable worth scenario. The effect of comparable worth on earnings inequality was assessed by calculating the coefficient of variation, variance of the natural log of earnings, the Gini coefficient, the Theil-Entropy Index, and Atkinson's measure of social welfare. We found a decrease in overall earnings inequality, inequality between women and men, and inequality among women. The decline in inequality held across choice of index.
Inauthenticity and Depression
Authors: ERICKSON REBECCA J. , WHARTON AMY S.
Published: March 2007

Interactive service jobs are an increasingly important feature of the occupational landscape. Despite over a decade of rising employment within this segment of the economy, researchers are only beginning to specify the occupational conditions of service sector jobs and the mechanisms through which such conditions may affect mental health. Here we examine the experience of inauthenticity on the job as useful not only for understanding workers' responses to particular facets of interactive service work but also for identifying the conditions under which such work may lead to increased psychological distress. Findings show that inauthenticity mediates the relationship between interactive service work conditions and depressed mood. Additionally, having to be good at people-handling skills tends to be associated with increased feelings of inauthenticity at work whereas working more frequently with other people and having control over one's work tend to reduce the likelihood of such feelings.
Reaching the Top
Authors: WILSON GEORGE , SAKURA-LEMESSY IAN , WEST JONATHAN P.
Published: March 2007

This study uses data from the 1988 to 1992 waves of the Panel Study of Income Dynamics (PSID) to assess predictions from the particularistic mobility thesis concerning how African American and White males reach the Managers-Administrators and Professional-Technical census-based occupational categories. The findings provide support for the particularistic mobility thesis. In particular, African Americans, relative to Whites, attain both occupational categories on the basis of a narrow and circumscribed route: for African Americans, the acquisition of significant human capital credentials and experience at a similar level in the occupational structure in next-to-last job with the same employer are important prerequisites for moving into privileged occupations. Furthermore, analyses indicate that particularistic employment practices are more pronounced in the private than the public sector. The implications of the findings for explaining racial differences in representation in the two occupational categories are discussed.
Mechanical Joining of Aramid Fibre Composites: An Experimental Study
Authors: De Koning C.A.M. , Van Dreumel W.H.M.
Published: March 2007

Mechanical joints of carbon fibre composite materials has been the subject of exten sive research in the past decade. Theoretical as well as experimental studies are avail able. In this article the structural use of aramid is examined by an experimental analysis of mechanical joints in various types of laminates. The relationship between bearing strength and laminate type and thickness is investigated and the influence of the pitch/ diameter ratio is studied. The safe failure behaviour typical of aramid composites is demonstrated by testing riveted joints.
Model for Predicting the Mechanical Properties of Composites at Elevated Temperatures
Authors: Springer George S.
Published: March 2007

A model is presented for predicting the changes in the mechanical properties of organic matrix composites exposed to elevated temperatures. The model can be used to calculate changes in the tensile, compressive and shear strengths and moduli as func tions of exposure time. The model also provides the decrease in the stress ratio with time and the time of failure.
Theoretical Evaluation of the Extent of the Mesophase in Particulate and Fibrous Composites
Authors: Theocaris P.S. , Philippidis T.P.
Published: March 2007

The concept of the mesophase and its extension in fibrous and particulate composite polymers has been investigated experimentally in the past. A theoretical method for the evaluation of the thickness of the mesophase is introduced in this paper. The method was based on the unfolding models, which describe the variation of the variable elastic- modulus, E,(r), of the mesophase material with respect to its thickness. By applying to E 1(r) the restriction based on the principle of continuity, that its variation curve must be tangent to the value of the constant elastic-modulus of the polymeric matrix, the thickness of the mesophase may be analytically determined. This is accomplished, of course, by the use of the appropriate models describing the properties of the com posite.

A review of the properties of the existing unfolding models indicated the possibility of a modification of these models. This modified unfolding model, with the already existing two-term model, yields a band, as lower and upper bounds respectively, in which lie all existing experimental values for the thickness of the mesophase for fibrous composites.

Numerical results derived from this theoretical treatment are in satisfactory agree ment with experimental values for fibrous composites, while for particulate composites there is a divergence between the theoretical and experimental values. The reasons of this fact are known and are explained in the appropriate section of this paper.
The Paraboloidal Failure Surface of Initially Anisotropic Elastic Solids
Authors: Theocaris P.S. , Philippidis T.P.
Published: March 2007

The generalization of the paraboloidal failure criterion for isotropic materials in order to cover anisotropic failure is presented in this paper. The resulting limit condition for anisotropic bodies is derived by a straightforward mathematical analysis based on physical grounds. The associated geometric interpretation of the failure condition in the principal stress space is an elliptic paraboloid having its axis of symmetry parallel to the hydrostatic axis and displaced from the origin of the coordinate system. All the geometric features of this failure surface, such as the orientation of the axes of its elliptic cross-sections, or the distance of the axis of symmetry from the hydrostatic axis, as well as the position of the open edge of the elliptic paraboloid with respect to the hydrostatic tension or compres sion half-spaces, depend on the degree of strength-anisotropy and strength-properties of the material.

Then, given the appropriate strength parameters in three mutually orthogonal material directions, coaxial with the resulting principal stress coordinate system, one has a clear and well defined geometric picture of the failure surface for three-dimensional stress systems. This is particularly useful since the effect of a prescribed loading path on the failure behaviour of a composite is determined by the position of its elliptic paraboloid failure surface with respect to material strength-axes.
Hydrostatic Response of Thick Laminated Composite Cylinders
Authors: Hyer M.W.
Published: March 2007

This study discusses the results of a layer-by-layer analysis of a thick-walled cross-ply graphite-epoxy cylinder subjected to external hydrostatic pressure. The analysis, which is valid away from the ends of the cylinder and is based on a generalized plane deformation elasticity solution for each layer, considers inter- and intralaminar stresses. Cylinders with 102 layers and radius to wall thickness ratios of 5 and 10 are studied. The influence of cur ing stresses are evaluated. For possible application to testing, the response of a thick lami nated ring is compared to the response of a cylinder. The idea of smearing the 102 layers into an equivalent single layer is discussed and the results of a smeared analysis are com pared with the layer-by-layer analysis. Finally, the responses of glass-epoxy and metallic cylinders are compared with the response of the graphite-epoxy cylinder. The primary findings of the study are: (1) the radial strain distribution through the thickness of the graphite-epoxy cylinder changes from extension at the inner radius to compression at the outer radius. This is different than the radial strain distributions through the glass-epoxy and metallic cylinders. The radial strains for these cylinders are everywhere extensional. (2) The magnitude of the curing stresses are much smaller than the stresses due to hydro static pressure. (3) The smearing technique works very well, the response predicted by the single-layer analysis being indistinguishable from the response predicted by the layer-by- layer analysis. (4) The high level of orthotropy of the graphite-epoxy causes a higher fiber loading than occurs for glass-epoxy. This effect could amplify any imperfections, e.g., fiber waviness, in the compressively loaded fibers and could lead to premature failure.
Effects of Stoichiometric Mixing Ratio on Epoxy Cure —A Dielectric Analysis
Authors: Day David R.
Published: March 2007

The goal of this study was to investigate the effects of epoxy/amine mix ratio on cure through the use of real time dielectric response. Microdielectric sensors were used to monitor molar mix ratios of EPON 828/DDS ranging from 3/1 to 1/3. Microdielectric results show that dielectric constant varies from about 9 to 30 with increasing DDS content in uncured resin. Times to the 10 kHz dipole loss peak during cures at 177°C are found to decrease with increasing DDS content. Above a ratio of 2/1 and below 1/2, due to the low molecular weight of the reaction products, loss peaks do not occur. Ionic conduction is shown to have a strong correlation with calorimetric kinetic cure data. The influence of both excess amine and excess DDS is to produce cured material with high ionic conduc tion levels. Deviations from ideal stoichiometery as small as 1.1/1 produce noticeable dif ferences in the finally cured network.
Damage Processes in Reinforced Reaction Injection Molded Polyurethanes
Authors: Kau C. , Hiltner A. , Baer E. , Huber L.
Published: March 2007

The microdeformation and damage mechanisms in glass fiber reinforced reaction injec tion molded (RRIM) polyurethane composites have been studied. Two surface conditions represented the extremes in good and poor fiber-matrix adhesion. Deformation mecha nisms observed directly by an SEM technique with the specimen deformed in three-point bend were correlated with the number and amplitude distribution of acoustic emission (AE) events detected during tensile testing. Yielding of the unreinforced resin was accom panied by microcracking initiated at holes that produced AE with a peak at 43 db. A simi lar AE pattern observed in the untreated fiber composites was also identified with micro cracking at holes in the resin and at rod-shaped holes produced by debonded fibers. The amine-treated fiber composite exhibited considerably more AE activity in the yield and post-yield regions with additional peaks in the amplitude distribution at 59 db and 65 db. These were identified with microcracking at the well-bonded interface and fiber fracture respectively.
Test Methods and Performance of Structural Core Materials -1. Static Properties
Authors: Feichtinger Kurt A.
Published: March 2007

The first in a series, this presentation describes the static mechanical test methods and response of structural core materials used in sandwich construction. The concept of sandwich construction is introduced wherein high strength facings are lami nated around lightweight cores. Benefits of this method of fabrication include higher strength and stiffness per unit weight compared with more traditional, homogeneous materials. A series of standardized test methods for characterizing the performance of structural cores is presented and the procedures, apparatus and relevance of each is dis cussed in detail. The core compressive, tensile, shear and flexural properties thus gener ated are necessary to the proper design of sandwich panels which may be subjected to static loading conditions. Three of the more prominent core types are compared on the basis of micro-structure and composition. These include end-grain balsa, hexagonal honeycombs constructed of aluminum or aramid fiber-paper and the polyvinyl cellular plastic cores. The results of our testing, performed on end-grain balsa core samples over a range of densities, are offered and compared with literature values of the other core materials. In subsequent presentations of this series, the time-dependent behavior and thermal response of structural cores will be addressed.
Determination of Fiber Volume Fractions by Optical Numeric Volume Fraction Analysis
Authors: Waterbury Mark C. , Drzal Lawrence T.
Published: March 2007

A method for determining the fiber volume fraction in continuous fiber composites by automatically counting the fiber ends per unit area in digitized microscope images of representative cross sections has been developed. Since fiber counts are digital variables, the accuracy of the method is essentially independent of small variations in microscope focus and specimen surface preparation. In addition to producing averaged data, the method enables the construction of volume fraction variation profiles ranging from the finest possible scales up to full size components. Results are in agreement with values obtained by acid digestion tests.
A Fracture Mechanics Approach to Interlaminar Failure of Unidirectionally Reinforced Composites
Authors: Palley Igor
Published: March 2007

Models are proposed for initiation and completion of failure in unidirec tionally reinforced composites under longitudinal shear. The models allow characteriza tion of the effect of fiber volume content on the average shear strength of composites con sidered as homogeneous material. Results are compared with experiments.
On the Design of the Cracked Sandwich Beam (CSB) Specimen
Authors: Carlsson L.A.
Published: March 2007

A design analysis of the cracked sandwich beam specimen for bondline shear fracture characterization is presented. The analysis enables selection of the appro priate core thickness, crack length and span length in order to achieve the desired debond ing failure mode prior to core crush or core shear failure.
Hygrothermal Effects on Chopped Fibre/Woven Fabric Reinforced Epoxy Composites. Part B: Degradation Studies
Authors: Shanker Singh K. , Singh P.N. , Rao R.M.V.G.K.
Published: March 2007

Studies were conducted on the degradation of short beam shear (SBS) and impact strength (Izod) properties of glass epoxy composite specimens with sequential ar rangements of woven roving (WR) and chopped strand mat (CSM) reinforcements, (Figure 1 of Part A) immersed in water at two different temperatures (298 K, 323 K).

It was found that composites with higher fibre content, though possessed of a higher ini tial shear strength, degraded faster than those with low fibre content. This was attributed to a thin resin layer separating the glass layers and a consequential increased surface area around the fibres for the moisture absorption. Further, it was noted that while the impact strength too degraded with exposure period, the degradation patterns are almost identical in all types of laminates within the limits of fibre resin ratio chosen.
Environmental Effects on the Compressive Properties: Thermosetting vs. Thermoplastic Composites
Authors: Haque A. , Jeelani S.
Published: March 2007

This article presents the influence of moisture and temperature on the compressive properties of T-300/epoxy, thermosetting and APC-2, thermoplastic com posites. All the specimens were designed using quasi-isotropic configuration of [+45°/ 90°/-45°/0°] s. A temperature range of 23°C to 100°C was considered for both the dry specimens as well as those exposed to distilled water for a period of 90 days. The effect of specimen geometry on the moisture absorption rate is also reported.
Influence of Circular Defects on the Flexural Strength of Kevlar/Epoxy Composites
Authors: Padmanabhan K. , Kishore
Published: March 2007

The flexural strength of the Kevlar/epoxy composite laminates, in the pres ence of unfilled and filled circular defects, was studied. Circular drillings of two different diameters extending up to the neutral axis from the compression face as well as through holes, at three different positions from the midspan, have been considered as simplified cases of dents and defects. Bonded buttons of aluminium metal have been tested and shown to yield a strength-wise compensation for test samples with depressions. Macrography of the failed specimens is also discussed.
A Simple Model for Brittle Composite Lamina with Damage
Authors: Chow C.L. , Yang F.
Published: March 2007

The paper focuses on the application of an anisotropic model proposed recently by the authors for damage assessment of brittle composite lamina. The formula tion is established based on the concept of damage surface and within the theory of small deformation and time-independent processes. The comparison between the experimental and predicted results has shown that the present method can be used adequately to approx imate the damage behaviors of brittle fiber-reinforced lamina under simple plane stress state and under proportional loading.
Failure by Shear of Transversely Isotropic Laminae Off-Axis Loaded According to the EPFS-Criterion
Authors: Theocaris P.S. , Philippidis T.P.
Published: March 2007

Failure prediction of off axis loaded fiber composite laminae are given, according to a failure criterion for generally anisotropic solids introduced by the authors. The failure condition used assumes that for any anisotropic solid a safe triaxial loading path exists, namely the hydrostatic compression, and thus the failure surface must be open-ended. By appropriately formulating the failure criterion, it is shown that the geo metric representation of the failure surface in the principal stress space is an elliptic para boloid (EPFS). In this paper the predictions of the above criterion for plane stress failure loadings of off-axis laminae, especially for shear induced failure, are compared with exist ing experimental data and are shown to be in satisfactory agreement.
A Model for Prediction of the Transverse Cracking Strain in Cross-Ply Laminates
Authors: Varna J. , Berglund L.A.
Published: March 2007

A modified variational analysis based on the principle of minimum com plementary energy, is used to describe the stress state around a through-the-thickness transverse crack in [0 m/90n]s cross-ply laminates. The analysis takes into account nonlinear stress distribution in the thickness direction of the 0°-plies and contains a thermoelastic consideration. A failure criterion based on linear elastic fracture mechanics is used to pre dict the onset of transverse matrix cracking in cross-ply laminates. The predictions are compared with experimental data and with previous analyses developed in the framework of the shear lag theory or the variational approach suggested by Hashin.
The Strength of Composite Repair Patches: A Laminate Analysis Approach
Authors: Robson J.E. , Matthews F.L. , Kinloch A.J.
Published: March 2007

Composite repair patches are often cured under vacuum pressure only, and are therefore more porous than their autoclaved counterparts. Thus it is common practice to add extra plies to a composite patch, over and above the number in the original struc ture. However, there is little published work on how the number of extra plies and their orientation should be chosen. By comparing the strength and stiffness of autoclaved and vacuum cured material, using classical laminate analysis, some guidelines for the selec tion of extra plies have been deduced.
On Flexural and Tensile Strength for Composites Manufactured by RTM
Authors: Holmberg J. Anders
Published: March 2007

The difference between tensile and flexural strength for a composite con sisting of vinylester reinforced with continuous E-glass fibres arranged in a random pat tern has been investigated. Both tensile tests and three- and four-point bending tests have been performed. It was found that the Weibull theory can be applied to explain the difference between ultimate strength in tension and bending provided that the theory is applied on fibre stress and not on some average composite stress. In addition it was found that influences of friction at the supports and large deflections has to be taken into account as well as nonlinear elastic material behaviour when glass fibre reinforced plastics are tested in bending. Simple closed form expressions which take these effects into account have been derived. A suggestion for proper evaluation of bending tests is presented in sum marized form in Appendix A.
Measurements for Determining the Thermal Expansion Coefficient (CTE) of Laminated Orthotropic Rings
Authors: Roy A.K. , Kim R.Y.
Published: March 2007

The thermal expansion coefficients of laminated rings are expected to be different from that of a flat plate or beam of the same laminate. The objective of this work is to characterize the thermal response of laminated orthotropic rings. From the measured thermal strains, the coefficients of thermal expansion (CTE) of the laminated rings are de termined. The tested rings are made of AS4/3501-6 composites and the lamination of the rings are [90]16 T, [90/0/ ±45]2 S and [90/ ±45]2 S.
Young's Modulus of a Composite: Reinforced with (n - 1) Different Inclusions
Authors: Rajesh Sharma , Anupam Sharma
Published: March 2007

A mathematical result is obtained for estimating the overall longitudinal Young's modulus of a unidirectional composite reinforced with ( n - 1) different inclu sions, so as to have an in-depth study of the work [1], which was restricted to two phase composite body. The distribution of stresses and strains are discussed in accordance with the corresponding elastic energies and the mixture is assumed to possess the properties described in Reference [1].
Progressive Failure of Laminated Composites with a Hole under Compressive Loading
Authors: Tan Seng C. , Perez Jose
Published: March 2007

A progressive failure model that was developed earlier for tensile loading is extended for laminated composites under uniaxial compressive loading. This model is capable of predicting the extent of damage at any load level, the stiffness loss, the stress- strain behavior and the residual strength of the laminates. The model is composed of the stress analysis, the failure analysis and a degradation model for the damaged lamina. Comparison with three sets of experimental data shows that good correlation was obtained between the theoretical prediction and the data for the ultimate strength. The predicted micro-damage includes matrix cracking and fiber breakage (shear crippling or microbuck ling) that agrees reasonably well with the experimental X-ray radiograph.
Development of Mathematical Tools to Determine Optimum Enclosure Designs for Controlling Electromagnetic Fields
Authors: Railkar Sudhir B. , Gokturk Halit S. , Kalyon Dilhan M.
Published: March 2007

Electromagnetic fields are present wherever sources of currents are found. Conventional shielding against these electromagnetic fields is accomplished by using com plete ferromagnetic enclosures. Maxwell's equations govern the phenomenon of electro magnetic fields in discontinuous media, and analytical solutions in the presence of enclo sures of arbitrary shapes are not available. Hence, Maxwell's equations are solved numerically using the finite element method in conjunction with the magnetic scalar potential approach. The test case for the verification of the numerical code is a long cylin drical ferromagnetic shell placed in a transverse uniform magnetic field for which an ana lytical solution is derived here. The comparison of analytical and numerical solutions vali dates the accuracy of the numerical code. As expected the magnetic field inside the complete enclosure varies inversely to the relative permeability of the enclosure. Using this approach, enclosures of different shapes can be designed.
RTMFLOT - An Integrated Software Environment for the Computer Simulation of the Resin Transfer Molding Process
Authors: Trochu François , Gauvin Raymond , Dong Ming Gao  , Boudreault Jean-François
Published: March 2007

The computer simulation of the injection phase in resin transfer molding (RTM) can help the mold designer to properly position the injection ports and the air vents, to select an adequate injection pressure, and to optimize the cycle time. The purpose of this article is to present RTMFLOT, an integrated software environment especially designed for the numerical simulation of the resin transfer molding (RTM) process. The main program modules are DATAFLOT, to evaluate the permeability of the preform, MESHFLOT, to produce a finite element mesh of the mold, FLOT, to compute the succes sive positions of the resin front, VISUFLOT, to visualize the numerical results, and HEATFLOT, to analyze the heat transfer phenomenon. The application of RTMFLOT to the design of a lawnmower hood is described in order to illustrate the various stages of the simulation process.
Postbuckling Response of Piece-Wise Uniform Tailored Composite Plates in Compression
Authors: Biggers Sherrill B. , Srinivasan Sundar
Published: March 2007

Tailoring, or precisely specifying, the types, amounts, orientations and locations of composite materials in a structure to satisfy specific performance require ments is inherent to the design of efficient composite structures. A simple piece-wise uni form stiffness tailoring concept has previously been shown to increase compressive buck ling loads of plates by as much as 138 % to 195% , depending on the baseline uniform laminate. The question arises as to what benefits, it any, exist for plates tailored in this way when loaded in the postbuckling regime. This paper presents predictions for global measures of the postbuckling response of plates loaded in compression which have been tailored to maximize the initial buckling load. The analysis shows that postbuckling loads at failure can be increased by 130% to 150% by tailoring. The edge strain at first-ply fail ure is not significantly affected by tailoring. Postbuckling membrane secant and tangent stiffnesses are much higher for tailored plates than for uniform plates. Out-of-plane postbuckling deflections are shown to be much smaller at a given load level when tailoring is employed. The initial buckling mode shape and the manner in which postbuckling mode changes take place are strongly affected by tailoring. Thus, with this design approach, op timization for initial buckling can provide concurrent benefits in postbuckling response. This improved performance suggests that the skin plate of stiffened composite panels could be tailored using the current approach to significantly improve the postbuckling perform ance of stiffened panels.