bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate and Crime
Authors: DeFronzo Jamesw
Published: March 2007

The Uniform Crime Reports published by the Federal Bureau of investigation state that climate has an independent impact on the variation of crime rates among places. The present study attempted to test this assumption through multivariate analyses of the potential impacts of three climatic and twelve nonclimatic factors on the variation in seven serious forms of violent crime and property crime among the 142 largest American SMSAs. The results indicated that the associations of climatic conditions with forms of crime were uniformly very weak compared to the influences of other variables. Number of days of the year with temperatures above 32.20C (900F) had independent positive associations with the variation in homicide rates and burglary rates while number of days with temperatures below 0°C (320F) and number of days with significant precipitation had positive associations with variation in robbery rates. Furthermore, number of days with freezing temperatures and number of days with significant precipitation had weak indirect negative associations with crime rates through correlations with percentage of SMSA population divorced or separated.
Toward a Theory of Situational Structure
Authors: Baumeister Roy F. , Tice Dianne M.
Published: March 2007

The independent variables for all studies published in odd-numbered volumes of the Journal of Personality and Social Psychology were recorded. The variables were then sorted on the basis of resemblance into an emerging scheme of categories. This procedure resulted in a list of 51 categories; this list arguably contains all dimensions of situational structure that have been shown to exert a significant effect on behavior. The 51 categories were then organized into a scheme of situational structure. The following 5 aspects of situational structure were suggested: the stimulus environment, which is comprised of the physical environment and the situation's temporal and spatial structure, as well as any social structure that is external to the subject; characteristics of the subject, which involve all relevant attributes of the subject as well as relevant prior experience; cognitive and affective dynamics, which involve the subject's attentional, interpretive, and emotional states and processes, as well as the subject's expectancies and goals; relationship background, which involves prior or incipient interactions between the subject and other people in the situation; and matrix of possibilities, which involves the range of behavioral alternatives available to the subject as well as the potential consequences and implications of various alternatives. The scheme is discussed in terms of issues of environmental psychology, especially environmental controllability.
Recycling as Altruistic Behavior
Authors: Hopper Joseph R. , Nielsen Joyce McCarl
Published: March 2007

Experimental and survey data were gathered from residents of a large urban neighborhood with a community wide curbside recycling program in order to determine the extent to which recycling could be conceptualized as altruistic behavior. Results confirmed that recycling behavior is consistent with Schwartz's altruism model, according to which behavior is influenced by social norms, personal norms, and awareness of consequences. Data further showed that a block-leader program, in which residents encouraged their neighbors to recycle, influenced altruistic norms and increased recycling behavior. Prompting and information strategies were also introduced into the community recycling program as experimental interventions in order to com- pare their effects with the block-leader approach. Results showed that prompting and information increased recycling behavior but did not affect norms and attitudes. Further- more, all the intervention strategies influenced behavior independently of the measured norms; block leaders had the most substantial impact, prompts had the next greatest impact, and information had the least.
Psychiatric Ward Renovation
Authors: Devlin Ann Sloan
Published: March 2007

Environmental improvements including new day hall furniture, plants, wallpaper and paint, and brighter lighting were carried out on four wards of a 40-year old state psychiatric facility. Staff on these wards rated environmental variables pre- and post renovation; behavioral mapping data for both patients and staff were also collected on one of those wards pre- and post renovation. Results indicate significant pre-post improvements in the ratings of day hall furnishings and plants. Significant main effects for ward were found in a number of environmental variables, reflecting the less demanding nature of the patient population and greater administrative support on these wards. Behavioral data showed a significant decrease in patient stereotypy and a preference for more private seating areas in the day hall following renovation.
Children and the Environment
Authors: Cohen Stewart , Horm-Wingerd Diane
Published: March 2007

The present study examined ecological awareness among preschool children. Three tasks were employed with 3-to 5-year-old boys and girls residing in rural and urban communities: a picture discrimination, a picture arrangement, and a picture comprehension task. It was found the young children are able to identify graphically depicted ecological issues with accuracy, relative to the nature of the task and its level of difficulty. It was also found that boys and girls, within the age range surveyed, were comparably aware of ecological issues. Moreover, no differences were found relative to the children's place of residence. The implications of these findings for ecological education and for advancing our knowledge of the development of ecological attitudes and behavior are discussed.
Windowlessness in the Workplace
Authors: Biner Paul M. , Butler Darrell L. , Lovegrove Theresa E. , Burns Rachel L.
Published: March 2007

A series of studies was performed to explore the hypothesis that employees in windowless offices compensate for the lack of windows. In Experiment 1, students rated the degree to which they perceived various office features to be substitutes for windows. Analyses revealed four general categories of potential window substitutes: other apertures (e.g., skylights), paintings/art, living things (e.g., plants), and panels (e.g., light panels). Experiment 2 supported the external validity of the data in Experiment 1 in that full-time office workers produced virtually identical ratings of window substitutability. Experiment 3 was a field study of 173 offices. Measurements were made of the number and size of windows, number and size of all potential window substitutes, and size of wall space available for pictures. Size was measured in degrees of visual angle from the office workers' chairs. No evidence was obtained to indicate that any of the features measured were more prevalent or larger in offices without windows. Furthermore, power analyses indicated that the study had sufficient power to find such effects. Experiment 4 was designed to investigate other potential reasons for the use of the items that were examined in Experiment 3. Several reasons, such as space personalization, were found to be perceived by office occupants as more important than the desire to compensate for lack of windows.
Changing Behavior and Making it Stick
Authors: De Young Raymond
Published: March 2007

A sustainable planet is not possible without patterns of conserving behavior. The resource-costly life-styles that are characteristic of the current scene present a historic challenge. Never before have so many behaviors needed to change in so short a time. More challenging is that they must stay changed. For many reasons the techniques commonly used to promote conservation behavior are more reliable at modulating short-term behavior than at achieving durable change. The perceived urgency of environmental problems tends to make immediate behavior change the major focus. But of equal importance is the stability of behavior once changed. Thus one goal of conservation behavior research is to discover techniques that change individual behavior while minimizing or eliminating the need for repeated intervention. This article categerorizes behavior change techniques first by their informational or motivational nature and second by the source of the change: derived from others or gained by direct personal involvement. Evaluating selected techniques using five proposed dimensions suggests why durable behavior change has been so hard to achieve. Research implications are discussed.
Constancy and Change in Attachments to Types of Settlements
Authors: Feldman Roberta M.
Published: March 2007

A consideration of both constancy and change in place attachments, focusing particularly on attachments to a type of settlement as a means by which the U.S. public may maintain the continuity of psychological bonds with places across changes of residence. Empirical evidence suggests that people form psychological bonds with types of settlements, expressions of which are similar to those identified in past research as indicative of psychological bonds with the tangible surroundings of the home, and that residential mobility may be best conceptualized as sustaining bonds, temporary dislocations, reunions, and reorientations in bonds with a type of settlement rather than as disruptions in bonding processes.
Multiple Effects of Home and Day Care Crowding
Authors: Maxwell Lorraine E.
Published: March 2007

As an environmental psychologist, her research interests are children's environments and environments for persons with special needs. She is currently doing research on the relationship between noise and preschool children's acquisition of prereading skills, environmental factors in preschool inclusive classrooms, and children's use of outdoorplay equipment. With a background in facility planning, she is also involved in architectural programming projects, of which a playground for both sighted and blind children is the most recent.
The Effect of Respondent Characteristics on General Environmental Attitude-Behavior Correspondence
Authors: Tarrant Michael A. , Cordell H. Ken
Published: March 2007

Five different environmental attitude scales were regressed on an 11-item self-reported general environmental behavior index derived from a confirmatory factor analysis. Correlations between each of the 5 attitude scales and the behavioral index were computed and a Fisher's Z-transformation was used to test for the effect of six respondent characteristics (gender, residence, education, income, age, and political orientation) on the attitude-behavior correlations. Although all of the five scales were significantly correlated with the behavioral index (p < .001), correlations for some attitude scales were highly affected by respondent characteristics. Of the 5 scales examined, the Environmental Concern (EC), New Environmental Paradigm (NEP), and Awareness of Consequences (AC) scales were associated most strongly with behavior, but the EC and NEP also were significantly affected by respondent characteristics. Implications for future studies and use of the scales are discussed.
Studio Instructors Talk about Skills, Knowledge, and Professional Roles in Architecture and Landscape Architecture
Authors: Sancar Fahriye Hazer , Eyikan Baris
Published: March 2007

This article examines the attitudes of studio instructors in architecture and landscape architecture departments throughout the United States toward the designer's role, sources of knowledge and inspiration in design, related disciplines, and essential skills. A cluster analysis of instructors' responses to a questionnaire identified five groups according to conceptions of professional identity: master designers, communicative designers, political designers, researcher designers, and those who see design, research, and political skills as almost equally important. The two most common self-conceptions are “master” and “negotiator.” In-depth interviews with some instructors further elucidated each approach. The results revealed the coexistence of a multiplicity of ideas and convictions within a shared ethos and suggested various strategies for increasing the effectiveness of design education and practice. The article concludes that the professional identity of designers is being transformed from that of isolated creative individuals to that of politically active professionals.
Multiple Occupancy Versus Private Rooms on Dementia Care Units
Authors: Morgan Debra G. , Stewart Norma J.
Published: March 2007

To manage the care of the increasing number of residents with dementia, many long-term care facilities have developed special care units (SCUs) to accommodate the unique needs of this group. Although private rooms have been recommended for SCUs, little is known about the effects of private versus multiple occupancy bedrooms. The opening of two new SCUs provided the opportunity to study the effect of multiple occupancy versus private rooms on the behavior of elderly residents with dementia. This article reports on quantitative and qualitative findings related to the change in bedroom type. Following the move to the new SCUs with private bedrooms, residents with advanced Alzheimer's disease and other dementias spent more time in their rooms during the day and required fewer interventions (including medications) to promote sleep at night. The article also includes staff and family caregiver perceptions of other advantages and disadvantages of the private rooms.
The Association of Forest Recreation with Environmentalism
Authors: Nord Mark , Luloff A. E. , Bridger Jeffrey C.
Published: March 2007

Associations of forest recreation with environmental concern and proenvironmental behavior are explored using telephone survey data from samples of forest landowners and nonowners in Pennsylvania. Frequency of visits to forest areas and forest recreation activities are moderately associated with proenvironmental behavior but only weakly associated with environmental concern.
Bypassing of Borders and Building of Bridges
Authors: Roth Lorna
Published: March 2007

This article conceptually frames First Peoples television development in Canada into historical periods divided on the basis of distinct cultural representational practices, improved technological infrastructures and corresponding expansions of target audiences. After characterizing each period, the focus turns to the most current phase - the licensing and launching of a new channel with mandatory carriage by cable operators - the Aboriginal Peoples Television Network (APTN), which went on air 1 September 1999. The only aboriginal television service in the world that is national in distribution, APTN carries six hours a day of original indigenous content (repeated three times), broadcasts in multiple languages and maintains the status of a fully independent broadcasting undertaking alongside Canada's two other national public services. Noting the controversy and significance of the bold and inclusive decision on the part of the Canadian Radio-Television Telecommunications Commission to license APTN, questions are then raised about the relationship between the technical location of the channel at the very high end of the Canadian broadcasting spectrum and the social position of sociocultural, political and economic marginalization of First Peoples in Canadian society. The extent to which First Peoples new visibility and audibility will build bridges of understanding or ignite existing negative stereotypes in cross-cultural audiences is yet to be determined, but the fact that APTN is now an integral member of Canada's national broadcasting infrastructure is internationally significant.
The Abolition of Copyright
Authors: Smiers Joost
Published: March 2007

There is convincing evidence that artistic life, which is an important sector in all societies, is better off when the concept of copyright disappears. In the digital era the concept is outdated anyway. As a consequence, our common artistic creativity will no longer be the exclusive property of a few copyright industries and piracy will cease to exist. Knowledge and creativity become once again essential elements of the public domain. Moreover, surprisingly, without the system of copyright protection many artists in both Western and non-Western countries will earn a decent income.
From the United States with News and More
Authors: Chang Tsan-Kuo , Lau Tuen-yu , Xiaoming Hao
Published: March 2007

The purpose of this study is to incorporate various theoretical approaches in international communication research into the world system theory and to test this model within a comparative design based on the data collected from six countries. The results show that core nations in the world system often dominate the flow of news and coverage in international communication. If an equation can be used, one core country covered in international news would be equal to two semi-peripheral countries and about seven peripheral nations.
Paper, Printing and the Printing Press
Authors: Gunaratne Shelton A.
Published: March 2007

The Chinese used paper for two or three centuries before CE 105, when Cai Lun, director of imperial arsenals under Emperor He of the later Han dynasty (25-220), officially reported the `invention' of paper. The Chinese began the first printed newspaper, Jing Bao (originally Di Bao), in 713 under the Tang dynasty (618-907); and it continued until the collapse of the Manchu dynasty in 1911. In 868, Wang Jie printed the famous Diamond Sutra (Kumarajiva's Vajracchedika Prajna Paramita), the earliest printed book in existence. Xylography (block printing) was known in China for at least four centuries before 932, when Prime Minister Feng Dao supposedly `invented' it by directing the printing of the 11 Confucian classics filling 130 volumes - a task that took 20 years. Alchemist Bi Sheng experimented with movable type for eight years from 1041, four centuries before Gutenberg. In 1313, Wang Zheng traced the development of movable type in his Nong shu, a treatise on agriculture. Chinese also made typography a fine art and produced numerous books. Printing from movable type reached its highest development in Korea from 1403 onwards. If the invention of printing ushered in the second communication revolution, then the celebration of Gutenberg as the inventor of printing represents a distortion of human history by those trying to document a so-called European `exceptionalism' of the 15th century. The horizontally integrative macrohistory approach should set the record straight.
Research Considerations for Effective Health Communication in Africa
Authors: Alali A. Odasuo
Published: March 2007

The purpose of this article is to provide a road map for health communication research in Africa. In the process, the author examines some of the theoretical constraints that impede health communication research in Africa. The discussion focuses on two key proposals for research: developing appropriate research methodology for health communication research; and creating evaluation tools that would enable assessment of health communication campaigns at three stages - planning, program operations and program outcomes. Additionally, the author recommends some specific ethical standards that should guide responsible health communication research in Africa.
Public Broadcasting and the Global Framework of Media Democratization
Authors: Raboy Marc
Published: March 2007

Public broadcasting remains a key institution of democratization in the context of globalization, marked by the shift from the national to the transnational as the site of media power and, increasingly, media activity. In the face of rampant commercialization of media, public broadcasting is essential to the promotion of pluralism in the public sphere. In a multichannel environment, public broadcasting must find its particular place. At the same time, multilateral politics present a specific new challenge to public broadcasting. As media politics go global, public broadcasting must be rethought and new structures and mechanisms put in place at the global level.
Negotiating Broadcasting Policy
Authors: Heath Carla W.
Published: March 2007

This article examines the nature of civil society and civic discourse in Ghana as they are reflected in the process by which broadcasting policy in that country is currently being negotiated. It is grounded in the notions that civil society is constituted by and in communication and that vital civil society and public discourse are essential aspects of a truly democratic system of governance. Public discussion of broadcasting policy began with a university conference in 1993; it gradually broadened to include members of radio audiences as well as officials, academics and a wide range of professional associations and media practitioners. In response to listeners' demands, public and private radio stations made available opportunities for on-air discussions of public issues. An apparent consequence of these programs is that Ghanaians feel more confident about participating in talking about and acting on other issues of public concern. Civil society has been strengthened.
Nature and Content of Tanzanian Non-Alignment
Authors: Gupta Vijay
Published: March 2007

Non-alignment is...simply a statement of a particular country that it will determine its policies for itself according to its own judgement about its needs and merits of a case. It is thus a refusal to be party to any permanent diplomatic or military identification with the Great Powers; it is a refusal to take part in any alliance or to allow any military bases by the Great Powers of the world. 1
Multiple Imaginings of Institutional Identity
Authors: Harrison Julia D.
Published: March 2007

In 1996-1997, the author conducted research at the Hanson Institute of Psychiatry, a large psychiatric research hospital in a North American city. The author came to understand that there was a desire on the part of some senior managers to cultivate a loyalty and a sense of responsibility among staff to a singular institutional identity. This issue frames this article, drawing on anthropological understandings of the idea of culture, Martin’s fragmentation model, Maffesoli’s ideas of the social imaginary, and Goffman’s discussion of the individual perspective of an organization from “in the cracks.” The author discusses the nested imaginings that any individual would have if one considers the institutional; professional, departmental, or occupational; and individual imaginaries that fuelled employees’ ideas of the institution. There could be no real imagining of “the Hanson” because individuals imagined they worked for “a Hanson,” each imagining a slightly different institution from “in the cracks.”
From Organizational Development to Change Management
Authors: Worren Nicolay A. M. , Ruddle Keith , Moore Karl
Published: March 2007

This article describes the emergence of change management as a service offering of major consulting firms. The authors compare change management with traditional organizational development (OD) in terms of theory and analytical framework, the role of the interventionist, and intervention strategies. They argue that change management has the potential to become a discipline that can unite the different “thought worlds” operating in the field of planned organizational change.
Consistent and Inconsistent Impacts of a Teacher-Led Empowerment Initiative in a Federation of Schools
Authors: Bartunek Jean M. , Greenberg Danna N. , Davidson Barbara
Published: March 2007

This study explores the impacts of a teacher-led empowerment initiative in a federation of independent schools. The authors used survey and archival data as well as a conceptual basis in consistency models to examine the relationship between participation in this organizational change initiative, individual behavioral changes pertinent to it, and ratings of its effectiveness. Results indicated that behavioral changes were strong predictors of individual ratings of the effectiveness of the initiative and partially mediated the relationship between participation and effectiveness ratings. Some results supported a consistency framework; others did not. Based on these results, the authors suggest implications for research and practice regarding empowerment-oriented and other types of organizational change initiatives.
Reading Literary Works by Black and White Writers
Authors: Cooke Gwendolyn
Published: March 2007

Absence of a segment of society in a sense falsifies literature, for a major merit of literature is that it broadens and deepens experiences. Furthermore, a great literature is relevant to people and to society as they are, and American literature surely is not relevant if it ignores 10 per cent of the Americans [Rose, 1968].
Structural Theory for Laminated Anisotropic Elastic Shells
Authors: Bert Charles W.
Published: March 2007

A linear theory is formulated for analysis of small deflections of thin shells with arbitrary geometrical configuration and laminated of an arbitrary number of layers of different thicknesses, orientations, and anisotropic elastic coefficients. An accurate shell theory (Vlasov's) is used, and the composite-shell constitutive relation incorporates the anisotropic stretching-bending coupling effects considered by Stavsky. For shells of arbitrary geometry, it is found necessary to introduce a new parameter Fij ≡ ∫h z 3Qijdz in the con stitutive relation. This parameter is zero for homogeneous aniso tropic materials and for anisotropic materials laminated symmetri cally with respect to the middle surface. However, for a two-layer filament-wound shell, this parameter can increase the flexural rigidity by 3%, which is greater than a 2% effect considered in a previous layered-anisotropic cylindrical shell analysis.
Carbon-Felt, Carbon-Matrix Composites
Authors: Granoff B. , Pierson H.O. , Schuster D.M.
Published: March 2007

Carbon-felt, carbon-matrix composites were prepared by the chemical vapor deposition of carbon within carbonized viscose-rayon substrates. The thermal and mechanical properties of these carbon-carbon composites were investigated over a wide range (9-46 v/o) of fiber volume percent. In creases in fiber content resulted in: (1) decreases in both total porosity and pore size, (2) filament and matrix reorientation, and (3) reduction of the pyrolytic carbon matrix sheath thickness. Fiber content, and its inter related effects, are correlated with significant changes in flexural and ten sile strength and modulus, thermal conductivity and linear thermal expansion.
Fatigue Behavior of Composite Laminate
Authors: Hahn H.T. , Kim R.Y.
Published: March 2007

The paper discusses a characterization of fatigue behavior of [0/±45/90] s glass/epoxy laminate in terms of the following parameters: static properties; S-N relationship; reliability; effect of thickness variation; damage initiation and growth; temperature increase; secant modulus change; effect of preloading on residual modulus and strength; and effect of ply failure on compression buckling strength. Some of the findings are the following. The primary failure process responsible for up to about 106 cycles of fatigue life is the wear-out followed by the chance failure. Change of secant modulus can be used as a measure of damage extent. Preloading to a high level has negligible effect on the residual tensile strength when the fatigue stress is low. However, ply failure and partial delamination result in a moderate loss of compression buckling strength.
Experimental Verification of an Accelerated Test for Predicting the Lifetime of Organic Fiber Composites
Authors: Chiao C.C. , Sherry R.J. , Hetherington N.W.
Published: March 2007

We have experimentally tested a model which is used to predict the stress-rupture lifetime of organic fiber composites. The experiment con sisted of a series of accelerated stress-rupture tests in which an aramid fiber impregnated with an epoxy resin was subjected to high temperatures and stresses. The resulting data were used to generate the model's material constants. The model was then used to predict the median lifetime of the composite at stresses and temperatures lower than those of the accelerated tests. A comparison of the model-predicted lifetimes at 25°C with 4 years of known stress-rupture data at room temperature showed that the experi mental data were in good agreement with model-predicted values. In a statistical analysis of the results, a Weibull distribution function with temperature-dependent parameters was assumed to describe the variability of lifetimes about the median lifetime.
The Effect of Stacking Sequence on the Pin-Bearing Strength in Glass Fibre Reinforced Plastic
Authors: Quinn W.J. , Matthews F.L.
Published: March 2007

The pin-bearing strength of glass fibre reinforced plastic plates was measured using specimens possessing mid-plane symmetry and composed of eight layers, two each at 0° , 90° , and ±45° . The results suggest that placing the 90° layer (normal to the applied load) at or next to the surface increases the bearing strength. The ultimate failure mode was found to depend on stacking sequence.
Dispersion of Acoustic Waves By an Alumina-Epoxy Mixture
Authors: Sutherland Herbertj.
Published: March 2007

A differential-path ultrasonic technique is used to obtain the acoustic wave propagation characteristics of a mixture of alumina (Al2O3) particles and epoxy (Epon 828-Z). Longitudinal and shear acoustic data are ob tained over a frequency range of 0.5 to 2 MHz and a temperature range of —61°C to 75°C. The longitudinal, shear, and Poisson's ratio master-curve material functions are derived from these data using techniques that were developed for homogeneous isotropic polymers. These functions constitute a complete material description for the mixture in the time (frequency) and temperature range where viscoelastic dispersion is the dominant disper sion mechanism in the composite.
Nonlinear Stress-Strain Response of Laminated Composites
Authors: Amijima Sadao , Adachi Tsuneyuki
Published: March 2007

This paper presents a simplified method of predicting the nonlinear stress-strain curves upt to the tensile and compressive failures for an unidi rectionally orthotropic lamina, symmetric biaxial and triaxial laminates. The analytical procedure is based on the classical Laminated Plate Theory (L.P.T.). With applying L.P.T. to the small sress or strain increments of the stress-strain curve, nonlinear stress-strain curve is continuously predicted for various laminates. Comparisons are made between analytical predic tions and experimental results. As the results, the nonlinear stress-strain curves for various cases could be estimated and the results have consider ably good agreement with experimental ones.
Application of the Cubic Polynomial Strength Criterion to the Failure Analysis of Composite Materials
Authors: Tennyson R.C. , Nanyaro A.P. , Wharram G.E.
Published: March 2007

A comparative failure analysis is presented based on the application of quadratic and cubic forms of the tensor polynomial lamina strength cri terion to various composite structural configurations in a plane stress state. Failure loads have been predicted for off-angle laminates under simple loading conditions and for symmetric-balanced laminates subject to varying degrees of biaxial tension, including configurations subject to multimode failures. Some experimental data are also provided to support these calcula tions. From these results, the necessity of employing a cubic strength criterion to accurately predict the failure of composite laminae is demon strated.
Transverse Behavior of Unidirectional Ribbon Reinforced METGLAS® / Epoxy Laminates
Authors: Yeow Y.T.
Published: March 2007

The finite element method (FEM) is used to model the elastic behavior of an epoxy based, rectangular shaped, metallic glass reinforced composite. Since a microscopic representation is utilized, the effects of reinforcement aspect ratio, volume fraction, amount of overlap and the distance between reinforcement along the width and thickness direction on the macroscopic transverse moduli and strength are determined.

Comparisons of the transverse moduli obtained from FEM, the Halpin- Tsai (H-T) equations and experiments are made for laminates containing various combinations of the parameters, mentioned above, The influence of these parameters on the transverse strength are identified.
The Effect of Temperature and Moisture Content on the Flexural Response of Kevlar/Epoxy Laminates: Part II. [ ± 45,0/90] Filament Orientation*
Authors: Allred Ronald E.
Published: March 2007

This study examines the effect of temperature and moisture on the flexural properties of quasi-isotropic Kevlar 49 fabric/epoxy composite laminates. Part I of this study treated the [0/90] filament orientation. Additional variables evaluated in Part II which were not studied in Part I include the effects of voids, long term moisture exposure, freeze-thaw thermocycling, the reversibility of moisture exposure and laminate unload ing behavior. Results indicate that the [±45,0/90] laminates exhibit a de pendence on temperature and moisture similar to the [0/90] laminates, but that the quasi-isotropic orientation is somewhat less sensitive to moisture at 21 and 150°C. Strength losses in the quasi-isotropic laminates can nevertheless be substantial. At 150°C and near saturation moisture content, the strength is 55-60 percent lower and the stiffness 40 percent lower than 21°C dry values. Voids, freeze-thaw cycling of specimens with voids and moisture, and long term moisture exposure all degrade laminate strength. Specimens subjected to long term moisture exposure followed by drying displayed stiffness values equivalent to as-fabricated results, but did not totally recover in strength properties. Flexural strengths of the dried specimens were similar to those of fully moisture saturated material at 21°C (15-20 percent loss from dry values). The lack of 100 percent re covery in strength indicates that moisture effects are not totally reversible. Microscopic examination of failed specimens showed no filament buckling at 21°C. Failures are characterized by a tensile delamination mode which may be induced by edge effects produced by the off-axis filament plies.
Wave Propagation Experiments On Ballistically Impacted Composite Laminates
Authors: Takeda Nobuo , Sierakowski Robert L. , Malvern Lawrence E.
Published: March 2007

The details of the time history of the elastic waves in ballistically im pacted composite laminates have been obtained by using surface and em bedded strain gages. Records show that a very low-amplitude in-plane tensile wave arrives first followed by a medium-amplitude flexural wave and then a high-amplitude flexural wave. Measured and calculated values of wave speeds agree well.
Calculation of Interlaminar Stress Concentration in Composite Laminates
Authors: Bar-Yoseph Pinchas , Pian Theodore H.H.
Published: March 2007

A new method for analyzing the free edge stress field in composite laminates is developed based on a perturbation and assumed stress approach. Convergence of the interlaminar shear stress in angle-ply laminates is studied.
Optimum Design of a Reinforced Cylindrical Pressure Vessel
Authors: Tauchert T.R.
Published: March 2007

The distribution of fibers in a cylindrically reinforced pressure vessel of given size and constituent properties is optimized using the criterion of minimum strain energy. A stress function approach, in conjunction with the modified Rayleigh-Ritz technique, is employed to obtain an approximate solution to the non-linear optimization problem. Constraint conditions in clude specification of the global volume fraction of fibers and satisfaction of stress boundary conditions. Numerical results are presented for reinforced cylinders having various radii, modulus ratios, and global volume fractions. Included is the case of a reinforced concrete cylinder, in which the concrete is assumed to be ineffective in tension. In most cases examined, use of the op timum fiber distribution, rather than a uniform distribution, results in a substantial reduction in the maximum radial displacement and an increase in the failure pressure load.
Moisture Diffusivity of Unidirectional Composites
Authors: Kondo Kyohei , Taki Toshimi
Published: March 2007

The moisture diffusion in unidirectional fiber-reinforced composite materials is formulated in terms of relative moisture concentration which cor responds to the temperature for the heat conduction problem. And the effec tive transverse moisture diffusivity of the composite materials with random array packing of fibers is predicted based on the properties of the constituent matrix and fibers by establishing a random array model. It is found that if the degree of randomness increases, the transverse diffusivity decreases remarkably. The theoretical prediction is in good agreement with the ex perimental data obtained by the authors and other researchers. And the analogy between the moisture diffusion and the thermal conduction or the longitudinal shear loading is discussed, pointing out some error in similarity used to predict the moisture diffusivity of composite materials in the literature.
Superposition Method for Analysis of Free-Edge Stresses
Authors: Whitcomb John D. , Raju I.S.
Published: March 2007

Superposition techniques were used to transform the edge stress problem for com posite laminates into a more lucid form. By eliminating loads and stresses not con tributing to interlaminar stresses, the essential aspects of the edge stress problem are easily recognized. Transformed problem statements were developed for both mechan ical and thermal loads. Also, a technique for approximate analysis using a two- dimensional plane strain analysis was developed. Conventional quasi-three-dimensional analysis was used to evaluate the accuracy of the transformed problems and the ap proximate two-dimensional analysis. The transformed problems were shown to be ex actly equivalent to the original problems. The approximate two-dimensional analysis was found to predict the interlaminar normal and shear stresses reasonably well.
Fatigue and Reliability Evaluation of Unnotched Carbon Epoxy Laminates
Authors: Radhakrishnan K.
Published: March 2007

An experimental test program has been carried out to verify the validity of a gen eralised residual strength degradation model for tension-tension fatigue of unidirec tionally reinforced unnotched carbon/epoxy composites. Further, the model is used for predicting the effect of a prior high load on the fatigue behaviour of these laminates. It is verified in the present program that a specimen is guaranteed to survive a certain minimum number of load cycles as predicted by the model after it has sur vived a proof load prior to fatigue. The correlation between statistical distributions of the fatigue life and the residual strength as predicted by the model and those deter mined experimentally, including the effect of proof load, is found satisfactory.
Probabilistic Failure Strength Analyses of Graphite/Epoxy Cross-Ply Laminates
Authors: Fukunaga Hisao , Chou Tsu-Wei , Peters P.W.M. , Schulte K.
Published: March 2007

This paper treats the failure characteristics of [0/90/0] and [90/0/90] cross-ply laminates based upon the statistical strength analysis. The stress redistributions at the failure of the 90 ° ply are analyzed using a shear-lag model, taking the thermal residual stresses and Poisson effect into consideration. The formulae for determining first cracking, subsequent multiple cracking and ultimate fracture are derived. The present analysis is compared with the existing experimental results for graphite/epoxy cross-ply laminates, and reasonable agreements have been obtained.
Stress Analysis of a Composite Plate with a Circular Hole under Axisymmetric Bending
Authors: Delale F. , Kishore N.N. , Wang A.S.D.
Published: March 2007

In this paper, the axisymmetric bending problem of a perforated plate which consists of two bonded isotropic dissimilar materials is considered. The problem is of interest in the delamination failure study of multilayered composites. From the plane elasticity solution of bonded isotropic materials, it is well-known that the interface stresses have a weak power singularity near the free boundary and this in turn may enhance the possibility of delamination failure. The solution given in this paper is based on the method developed in [1]. An elasticity series solution of the axisymmetric bending problem is presented. This can be considered as the first component of the general bending problem. The stresses exhibit the expected singular behavior around the hole boundary. The results are also compared with those obtained by using the Finite Ele ment Method. It is observed that the two sets agree rather well with regard to trend and magnitude of interface stresses.
Stresses Around a Pin-loaded Hole in Orthotropic Plates
Authors: Zhang Kai-Da , Ueng Charles E.S.
Published: March 2007

A compact analytical solution of stresses around a pin-loaded hole in orthotropic plates is obtained by the complex stress functions which satisfy the displacement boundary conditions along the hole. In the solutions, two parameters n and k which characterize the orthotropy are involved. Frictional effects are included. The advan tage of these solutions is that the stress distribution along the hole can be easily com puted for different orthotropic materials as long as the basic elastic constants are known. The numerical results are compared with those available in the literature.
Residual Strength Prediction of Impacted CFRP Laminates
Authors: Caprino G.
Published: March 2007

A model for the prediction of residual tensile strength of impacted CFRP laminates is presented and discussed. The damage zone is considered, from the residual strength standpoint, as an equivalent implanted hole, and strength degradation is calculated using a linear elastic fracture mechanics approach previously proposed. The results of experimental tests, carried out at low velocity on AS/3501 (0/±45) 2s laminates, show a good correlation with theoretical predictions; moreover, data available in the literature seem to indicate the effectiveness of the proposed formula in foreseeing the com pressive strength degradation due to impact.

The physical meaning of the parameters appearing in the model, together with the data here presented, suggests a method to obtain the residual strength curve as a func tion of impact energy by a minimum number of experimental tests. This method is ex pected to be valid for rate-insensitive materials such as carbon fiber reinforced laminates.
Studies on Lightweight Glass Fibre-Resin Composites by Destructive and Nondestructive Methods
Authors: Järvelä Pentti , Laitinen Keijo W. , Purola Jaakko J. , Törmälä Pertti
Published: March 2007

The relationship between the structure and properties of very lightweight glasswool- phenolformaldehyde resin composites was studied by measuring the composite strength and elasticity properties. The fibre structure of the examined composite (den sity 10 ... 40 kg/m3 and resin concentration 1 ... 13 w-%) was found to be almost random in two directions, while in the third direction there were relatively few fibres. It was found that the elasticity properties of the composite after compression decrease as a function of time and the degree of compression. This phenomena can be explained by the static fatigue of the glass fibres, which means that their strength depends on the length of time that a load is applied or on the loading rate [1].

It was shown that the values of destructive tests (tensile strength), as well as such material parameters, like density and binder phase concentration are possible to be determined with nondestructive tests (the damping test).
Predicting Crack Growth Direction in Unidirectional Composites
Authors: Gregory M.A. , Herakovich C.T.
Published: March 2007

The purpose of this study is to gain a better understanding of the parameters affect ing crack growth direction in unidirectional composite materials. To achieve this, the effect of anisotropy and biaxial, far field loading on the direction of crack growth in unidirectional off-axis composite materials is investigated. Specific emphasis is placed on defining the crack tip stress field and finding a consistent criterion for predicting the direction of crack growth.

An anisotropic crack tip stress analysis was implemented using three criteria (the normal stress ratio theory, the tensor polynominal failure criterion and the strain energy density theory) to predict the direction of crack extension in unidirectional off- axis graphite-epoxy. The theoretically predicted crack extension directions were then compared with experimental results. After comparison, it was determined that only the normal stress ratio criterion correctly predicts the direction of crack extension.
A Comparison of Fracture Toughness of Matrix Controlled Failure Modes: Delamination and Transverse Cracking
Authors: Shaw Ming Lee
Published: March 2007

Delamination and transverse cracking failure modes of composites have been char acterized by using the width tapered double cantilever beam test and the double torsion test, respectively. The fracture toughness GIC values obtained from the two tests are found to be quite comparable. This indicates that the two failure modes have similar failure mechanisms. The phenomenon of fibers bridging between crack surfaces observed in the tests is also discussed for its relevance to the laminate fracture.
A Theoretical Investigation of Accelerated Aging in Metal-Matrix Composites
Authors: Dutta I. , Bourell D.L. , Latimer D.
Published: March 2007

Accelerated aging of precipitation hardening alloys reinforced with particulates or fibers has often been attributed to an increase in dislocation density in the immediate vicinity of the reinforcement. The plastic zone is generated during cooling from the solutionizing temperature due to a mismatch in thermal expansion coefficients of the matrix and the reinforcement. In this work, continuum mechanics and finite element approaches were used to develop models to calculate the plastic strain and the expended plastic work in the matrix in terms of the solutionizing temperature, matrix yield strength and elastic con stants, and the reinforcement volume fraction. The information obtained was then used to relate the degree of accelerated aging with the state of plastic strain of the matrix. It was assumed that the plastic zones from adjacent reinforcements are non-interacting and that the reinforcement is incompressible. Aging curves were generated for a monolithic 6061 Al alloy and fiber composites with 10v/o and 30v/o SiC. It was found that composites with a higher volume fraction of SiC age faster. Aging data generated for the monolithic alloy strained plastically after quenching were compared to those for the composites to deter mine the reliability of the model in determining the degree of accelerated aging, based on materials parameters and reinforcement morphology.
Thermo-Oxidative Stability Studies of Celion 6000/PMR-15 Unidirectional Composites, PMR-15, and Celion 6000 Fiber
Authors: Bowles Kenneth J. , Nowak Gregory
Published: March 2007

Studies were conducted to examine the influence of the thermo-oxidative resistance characteristics of the fiber and matrix resin on the thermal stability of composites made from these materials. Celion 6000 graphite fiber, PMR-15 matrix resin, and Celion 6000/PMR-15 unidirectional composites were isothermally aged in air-circulating ovens at 288, 316, 329, and 343 °C. Microscopy (SEM) studies indicate extreme oxidative erosion of the graphite fiber occurs at elevated temperatures in the presence of the polyimide matrix. Activation energies were calculated for the thermal degradation of the three materials. The activation energy of oxidation of the composite was found to be greater than those of the fiber and the matrix resin.