bluuebunny/crossref_metadata_2025 huggingface dataset:
An Assessment of the Interlaminar Stress Problem in Laminated Composites
Authors: Salamon Nicholas J.
Published: March 2007

A review and assessment of the interlaminar delamination problem com mon to layered composite materials is presented. The work covers calcula tion of interlaminar stresses from a homogeneous and microstructural material viewpoint as well as background information on the singularity problem. The observation of edge delamination and experimental efforts are discussed together with recent fracture mechanics studies. The conclu sions provides an assessment of the problem and suggestions for future investigation.
Graphite/Epoxy [ ± 45]s Tubes. Their Static Axial and Shear Properties and Their Fatigue Behavior under Completely Reversed Load Controlled Loading
Authors: Rempl Erhard K , Niu Tyan-Min
Published: March 2007

Fixtures are described which are appropriate for static and fatigue testing of thin-walled composite tubes of 25.4 mm outer diameter and for use in an MTS servohydraulic tension-torsion system. The room temperature static ax ial and shear properties of tubes consisting of four layers of [ ± 45]s graphite epoxy were determined using axial and axial/shear clip-on extensometers where appropriate. Elastic moduli are equal in tension/compression (tor sion/reversed torsion). Ultimate tensile and compressive strengths are nearly equal. The torsional strength depends strongly on the direction of twist. Beyond the relatively small elastic range time-dependent deformation is observed which is also felt as a frequency effect on fatigue life under com pletely reversed axial load controlled loading. The room temperature axial fatigue strength amplitude at 105 cycles is approximately thirty percent of the ultimate strength.
Micromechanical Predictions of Crack Initiation, Propagation and Crack Growth Resistance in Boron/ Aluminum Composites
Authors: Mahishi Jayant M. , Adams Donald F.
Published: March 2007

An elastoplastic, axisymmetric finite element model has been used to predict the initiation and propagation of a crack in a composite model consisting of a single broken boron fiber embedded in an annular sheath of aluminum matrix. The accuracy of the axisymmetric finite element model for crack problems has been established by solving the classical problem of a penny-shaped crack in a thick cylindrical rod under axial tension. Also, the stress intensity factors predicted by the present numerical model are compared with continuum results. A constant displacement boundary condition applied during an incre ment of crack growth permits a substantial amount of stable crack growth in the matrix material. The concept of Crack Growth Resistance Curves ( KR curves) has been used to determine the point of crack instability.
Numerical Prediction of Fiber Orientation in Dilute Suspensions
Authors: Givler Richard C. , Crochet Marcel J. , Pipes R. Byron
Published: March 2007

A numerical scheme for the determination of the fiber orientation state in dilute suspensions is developed. Fiber orientations are calculated from the numerical integration of Jeffery's orienta tion equation along the streamlines obtained on the basis of the finite element method. Numerical solutions of the fiber orientation state are presented for the simple shear flow, the fountain flow and the flow in an infinite expansion.
A Method to Calculate Effective Modulus of Hybrid Composite Materials
Authors: Oshima N. , Nomura S.
Published: March 2007

A theoretical model for estimating the effective elastic modulus of particulate hybrid composites is proposed. A concept of "equivalent virtual volume fraction" is in troduced in order to take interaction among a matrix and inclusions into account. The model is illustrated by the effective shear modulus of particulate hybrid composites based upon a modified self-consistent method for two-phase composites. The obtained results reflect the influence of the matrix phase geometry more adequately than simple "self-consistent" models.
Response of Quasi-Isotropic Carbon/Epoxy Laminates to Biaxial Stress
Authors: Swanson S.R. , Christoforou A.P.
Published: March 2007

The results of biaxial tension tests on AS4/3501-6 carbon/epoxy are presented for a quasi-isotropic [90, ±45,0]s laminate. These tests were performed using a tubular spec imen subjected to internal pressure and axial tension. The specimen design appears to minimize stress concentrations in the gage section. The measured stress-strain response shows a small but definite reduction in stiffness associated with progressive matrix failure. The failure stresses and strains are consistent with a maximum fiber strain failure criterion, and are most accurately modeled with a progressive failure model that incor porates ply stiffness changes.
Tensor Transformations and Failure Criteria for the Analysis of Fiber Composite Materials
Authors: Christensen Richard M.
Published: March 2007

Classical lamination theory for fiber composites is inherently limited to the 2-dimen sional conditions appropriate to thin shell configurations. A new derivation with ap propriate tensor transformations is given which provides a fully 3-dimensional lamination theory that is applicable to thick laminates involving "out-of-plane" stress terms. In con nection with this work a new failure criterion is derived for fiber composites, one which involves a minimum number of failure parameters, and offers insight into the modes of failure. The key to both derivations is the restriction of the five properties form of transversely isotropic media to a special form involving three independent properties. The reduced theoretical forms and the failure criterion are evaluated with respect to standard experimental data for fiber composites.
Laser-Induced Damage Mechanisms of Kevlar 49-Epoxy Composites
Authors: Morgan Roger J. , Kong Fung-Ming , Lepper Jay K.
Published: March 2007

The laser-induced damage mechanisms of Kevlar 49-epoxy composites are reported.
Studies on Mechanical Behaviour of the Cast and the Forged Al-Graphite Particulate Composites
Authors: Pillai U.T.S. , Pandey R.K.
Published: March 2007

Al-Graphite composites have been prepared using liquid metallurgy technique with Al-3 % Mg as the base alloy. The composites of three different volume fractions varying from .022 to 0.067 and three different particulate sizes (75-250 μm) have been used for the study. The microstructure, particule size distribution and tensile properties have been studied in both the cast and the forged conditions of the composites. The main findings are that the strength and ductility

1. Decrease with increasing vol. % of graphite

2. Increase with particulate size at a given vol. % of graphite

3. Increase with inter-particle spacing

A comparison has been made between the cast and the forged composites with respect to strength and ductility. The tensile fracture strain in these composites appears to follow Thomosan's void coalescence model. The micromechanism of fracture has been studied using SEM and the results have been correlated with the tensile properties.
A Nonlinear Analysis of the CLS Specimen
Authors: Gustafson Claes-Göran , Hojo Masaki , Holm Dan
Published: March 2007

A nonlinear analysis of a cracked lap shear (CLS) specimen was carried out based on the theory for tie rod problems. The specimen in this case was an unidirectional Ciba Geigy T300/914 laminate with orientation and layup of (0°)9 at the thick section and (0°)5 at the thin section.

In the tie rod analysis the CLS specimen was modelled as two beams joined eccen trically with the joint at the crack tip. The analysis gave the distribution of bending moments and shear forces along the CLS specimen, the deflection of the CLS specimen and the total energy release rate ( G) associated with delamination growth. The energy release rate was found to be independent of the crack length except for long crack lengths. In order to separate the mode I and mode II contributions of the energy release rate, bend ing moments and shear forces were calculated at a distance from the crack tip. The cross- sectional forces and bending moments were thereafter used as prescribed loads in a linear finite element analysis of a short section containing the crack tip. Using a crack closure scheme, the mode I ( GI) and mode II ( GII) energy release rates were calculated. The agreement in total energy release rate calculated from the tie rod analysis and the finite element analysis was good.
An Analysis of Shear Failure Mechanisms for Compression-Loaded [±θ] S Laminates
Authors: Shuart Mark J.
Published: March 2007

An analysis of interlaminar and in plane shear failures for [±θ]s composite laminates loaded in uniaxial compression is described. A laminate model is presented that idealizes each ply as a plate supported by an elastic foundation. A nonlinear analysis for plies with short-wavelength initial imperfections is used to determine laminate stresses and in terlaminar strains. A failure criterion that uses the results of the nonlinear analysis is intro duced.
Die-Less Forming of Thermoplastic- Matrix, Continuous-Fiber Composites
Authors: Miller Alan K. , Gur Micha , Peled Ady , Payne Alexander , Menzel Erik
Published: March 2007

A die-less forming process is described which is intended to be an eco nomical method for manufacturing large, complex-shaped components from thermoplastic matrix, continuous-fiber composite materials. The concept is specialized to tapered shapes which are singly curved, long in their straight direction, and of arbitrary variable cross section along their length. An array of universal, computer-controlled rollers generates such shapes from initially flat laminates or stacks of prepreg sheet. Heating and bending of the material are strictly local operations occurring only within a small active zone at any one instant, thereby eliminating the need for fixed tooling and for large autoclaves or presses. The rollers are controlled using a "kinematically admissible bending" algorithm which requires interply sliding only in the local hot zone. Despite the fact that all of the regions not being formed are cold and rigid, the fibers of the composite are not forced to change length.

Experimental verification to date includes: (1) rapid, local, through-thickness induction heating of carbon fiber, polymer matrix composite workpieces, and (2) kinematically- admissible bending of preconsolidated thermoplastic matrix laminates to simple singly- curved shapes, using a "near-term demonstration" forming machine. Tension superim posed during such bending operations has been shown to be useful for maintaining good fiber alignment.
A Study of Structural Composite Tee Joints in Small Boats
Authors: Shenoi R.A. , Violette F.L.M.
Published: March 2007

The paper examines the influence of joint geometry on the ability to transfer out-of-plane loads for a hull bulkhead joint in small boats. The hull bulkhead assemblies have been designed on the basis of sandwich beam and laminated plate theories. An analytical solution has also been developed to predict the failure load. Experimental speci mens have been produced and tested to failure in order to be compared with the analytical method. Finally, a design tool based on the analytical model and the factors affecting cost and weight efficiency of the joint has been produced for practical engineering purposes.
Inelastic Response of Hybrid Composite Laminates
Authors: Hidde Jeffrey S. , Herakovich Carl T.
Published: March 2007

A model for predicting the nonlinear response of hybrid laminates sub jected to thermomechanical loads is presented. The theory accounts for the residual stress state present in the laminate following the cure cycle. Predictions of the model are com pared to the measured response of 0° and 90° coupons for two different ARALL® lami nates. Excellent agreement is found between predicted and experimental results for the tensile response and good agreement is found for the Poisson's response.
Polyethylene-Ultra High Modulus Polyethylene Short Fibers Composites
Authors: Ajji A. , Ait-Kadi A. , Rochette A.
Published: March 2007

Composites based on chopped ultra high modulus polyethylene fibers (UHMPE) and low density polyethylene (LDPE) were prepared in the melt state. It is shown that the UHMPE fibers do not melt during the preparation operations, and an im portant enhancement of the mechanical properties is obtained as a function of fiber content and length. The efficiency of these fibers was found to be comparable to those of Kevlar® fibers, and higher than those of glass fibers. An important transcrystalline region has been observed for all the fibers, however, its effect on their efficiency as a reinforcing agent is questionable. It is also shown that UHMPE fibers can advantageously replace Kevlar® fibers in some particular applications.
Interfacial Shear Stress Distribution in Model Composites Part 2: Fragmentation Studies on Carbon Fibre/Epoxy Systems
Authors: Melanitis N. , Galiotis C. , Tetlow P.L. , Davies C.K.L.
Published: March 2007

The micromechanics of reinforcement of a model composite system con sisting of a continuous high-modulus (HM) carbon fibre embedded in an epoxy resin have been investigated. The composite was subjected to incremental tensile loading up to full fibre fragmentation, while the strain in the fibre was monitored at each level of load using a laser Raman spectroscopic (LRS) technique. The average strain in the fibre increased linearly with applied matrix strain up to a value of 0.8 %, when the first fibre fracture oc curred. After fracture, the strain in the fibre was found to build from the tips of the fibre breaks, reaching a maximum value in the middle of each fragment. The shape of the load transfer profiles at the locality of the fibre tips indicated that the stress transfer efficiency had been affected by the fracture process. The length of interfacial debonding at the point of fibre fracture was found to be driven by the strain energy of the fractured fragments.

The interfacial shear stress (ISS) distributions at various levels of applied load along in dividual fragments, have been derived from the load transfer profiles using a balance of forces analysis. The shape of the ISS profiles confirmed that interfacial debonding initiated from the tips of the fibre breaks, whereas good fibre/matrix adhesion was retained around the mid-length of each fragment. By increasing the applied strain to 1.8%, the maximum ISS values also increased in spite of the presence of debonding at the fibre tips. An upper ISS limit of 42 MPa was calculated at this point. Further increases of the applied strain to 5% resulted in significant reductions in the values of the maximum ISS, as well as an in crease, of the frictional slip towards the middle of each fragment. Finally, by employing the assumptions of the conventional fragmentation test, the calculated value of the nominal interfacial shear strength at the point of full fragmentation was lower by a factor of 2 than the value measured by the LRS method.
Thermal Diffusivities of Composites with Various Types of Filler
Authors: Hatta Hiroshi , Taya Minoru , Kulacki F.A. , Harder J.F.
Published: March 2007

In-plane and out-of-plane thermal diffusivities (conductivities) of Kerimid resin composites reinforced with various types of filler were studied both experimentally and theoretically. The types of filler used are SiO2 particle, Al2O3 short fiber, Boron Nitride (BN) flake, and Si3N4 whisker. The prediction based on our previous model (Eshelby's equivalent inclusion method) agreed reasonably well with the experiment, except for BN flake composite. It was found that the orientation of filler has a strong effect on the overall thermal conductivity of a composite.
Permeability of Unidirectional Reinforcements for RTM
Authors: Gebart B.R.
Published: March 2007

The permeability of an idealized unidirectional reinforcement consisting of regularly ordered, parallel fibres is derived starting from first principles (Navier-Stokes equations) both for flow along and for flow perpendicular to the fibres. First, an approx imate analytical solution for transverse flow is derived which differs from the Kozeny- Carman equation for the permeability of a porous medium [9] in that the transverse flow stops when the maximum fibre volume fraction is reached. The solution for flow along the fibres has the same form as the Kozeny-Carman equation. A comparison shows excellent agreement between a numerical solution of the full flow equations and the approximate one at medium to high fibre volume fractions ( V f > 0.35). The theoretical predictions of permeability were tested in a specially designed mould. The results from the experiments with an unsaturated polyester resin (Jotun PO-2454) and the unidirectional reinforcement did in all cases show excellent agreement with results predicted by Darcy's law (the square of the flow front position increases linearly with time if the injection pressure is kept con stant). The theoretical model could be fitted to the experimental data both for flow along the fibres and for cross flow based on data for flow along the fibres only. The fitting is ob tained by adjusting one parameter in the model, the effective fibre radius, to a value about four times larger than the real fibre radius (15 μm). Scanning electron microscopy shows that the fibres are arranged in bundles looking like cylinders with ellipsoidal cross section which may be the explanation for the effective fibre radius in the fitted model equation be ing larger than the real fibre radius.
Biaxial Flexing of a Unidirectionally Reinforced Aluminum Composite
Authors: Tsangarakis Nikos , Pepi Marc S.
Published: March 2007

Aluminum disks reinforced unidirectionally with silicon carbide con tinuous fiber were supported circumferentially on one side and loaded at the center of the other side with a pin. Maximal principal tensile surface strains were determined during flexing with strain gages.

Failure under monotonic loading initiated on the convex side of the disks with the for mation of multiple surface matrix cracks which were parallel to the fibers. These cracks formed soon after matrix yielding which initiated at a strain 0.0015-0.002. On cyclic ten sile biaxial flexing, surface matrix cracking was found to be the main failure mechanism. A limited number of disks failed by fiber cracking. The endurance strain limit for 107 cycles of life was 0.001. This strain is only 11 % of the uniaxial monotonic tensile strain to failure. Ultrasonic velocity scans successfully identified the damage generated during cyclic loading.
Effects of Multiple Delaminations on Compressive Buckling Behaviors of Composite Panels
Authors: Suemasu Hiroshi
Published: March 2007

Compressive buckling stability of composite panels with through-width, equally spaced multiple delaminations are investigated analytically and experimentally. An analytical method is formulated on the basis of Rayleigh-Ritz approximation tech nique. Timoshenko type shear effects are included. An experiment and a finite element analysis are also conducted on the present model. The analytical results agree very well with the experimental and finite element results. The buckling load, which is the com pressive strength of the panel in the case of the present model, reduces significantly due to the existence of multiple delaminations. The mechanism causing the significant loss of the compressive buckling load due to the delaminations is well explained.
Measurement of Play Structures
Authors: Bower Eli M. , Ilgaz-Carden Ayse , Noori Kathryn
Published: March 2007

"A Play Box" containing thirty wooden pieces was developed and used with populations of Iranian and Turkish children. A consistency of play was found in repeated administrations. Differences in the use of space was noted between the two groups as well as socioeconomic status (SES) differences in the Iranian population. A surprising finding was absence of SES differences among the Turkish sample possibly attributable to the nature of the preschool program in Turkey.
Children'S Appreciation of Humor Victimizing Different Racial-Ethnic Groups
Authors: McGhee Paul E. , Duffey Nelda S.
Published: March 2007

This study examined the early development of humor depicting victims of other racial-ethnic groups among low-income black, Mexican American, and white children and middle-income white children. Boys and girls between 3 and 6 years of age were presented with pairs of drawings differing only in the identification of the victim of a minor mishap and were asked to choose the funnier of the two. The pairs included the following comparisons: black versus white victim, black versus Mexican American victim, and white versus Mexican American victim. As hypothesized, only white children found it funnier to see a child of another racial-ethnic group victimized in humor than a child of their own group. This occurred for both low- and middle-income children. The lack of significant humor preferences among black and Mexican American children are explained in terms of their greater ambivalence regarding early positive identification with their own racial-ethnic group.
The Effect of Schooling on Conservation Skills
Authors: Rogan John M. , MacDonald M. Allyson
Published: March 2007

Previous studies have tried to explain or predict conservation skills in terms of "schooled" or "unschooled." In this study, an intervention in some schools in the Ciskei, South Africa, is described and its effect on conservation skills is investigated. The results suggest that the acquisition of conservation skills may depend more on factors such as physical and mental interaction with the environment, and the type of reasoning to which a child is exposed, than on schooled and unschooled categories.
Social Loafing in Cross-Cultural Perspective
Authors: Gabrenya William K. , Latane Bibb , Wang Yue-Eng
Published: March 2007

Research conducted in the United States indicates that people exert greater effort in a variety of task situations when they perform individually than when they do so in a group that obscures identifiability of members' individual outputs, a phenomenon termed "social loafing." It was hypothesized that members of cultures whose value emphases and social institutions have been characterized as "group-oriented" would tend to form more cohesive groups and be more likely to place group benefit over individual benefit than members of individualistic U.S. culture, hence evidencing less social loafing. Contrary to this expectation, Chinese school children on Taiwan (grades 2 through 9), asked to produce sound by clapping and shouting alone and in pairs, evidenced levels of social loafing similar to those obtained in U.S. research employing this procedure. Several sources of this absence of a relationship between social loafing and cultural values are discussed, including the effects of the social restrictiveness of the sound production procedure on its ability to tap cultural differences.
The Development of Ethnic Attitudes
Authors: Aboud Frances E. , Skerry Shelagh A.
Published: March 2007

Empirical research reported in the literature over the past 18 years was integrated and critically evaluated to determine the age at which ethnic attitudes are formed, their course of development after this age of onset, and psychological factors influencing attitude development. Conclusions were drawn about the effects of age and ethnic status that differed in certain respects from those made a decade ago. The development of ethnic attitudes was found to parallel certain developments in affective, perceptual, and cognitive processes, such as the differentiation between groups and between individuals. Within this framework, differences between majority and minority children were discussed in terms of the effects of social factors on affect, perception, and cognition.
Social Comparison in High- and Low-Status Groups
Authors: MacKie Diane
Published: March 2007

New Zealand Pakeha (of European descent) and Samoan schoolchildren were asked to name both positive and negative reference others on three dimensions provided by experimenters of their own sex and ethnic group membership. Subjects produced reference others after the standing of their group on either a socioeconomic or a cultural-linguistic dimension had been made salient in order to manipulate status. When a dimension on which their group had low status was made salient, children used group enhancement strategies of social comparison, making more positive references to the ingroup than the outgroup, and more negative references to the outgroup than the ingroup. When group status was high, Samoan children made equal numbers of positive and negative comparisons to the in- and outgroups whereas Pakeha children tended to restrict references to the membership group only. The making of intergroup comparisons favorable to the ingroup when status is low is consistent with research showing that such a pattern of comparisons enchances self-regard. The possibility that the informational rather than the evaluative function of comparison becomes more important when high status is salient is also discussed.
Measured Acculturation and MMPI-168 Performance of Native American Adults
Authors: Hoffmann Tom , Dana Richard H. , Bolton Brian
Published: March 2007

To test the hypothesis that acculturation influences MMPI performance of Native Americans, a 32-item instrument was developed to measure five components of acculturation. The MMPI-168 and the acculturation instrument were administered to 69 Rosebud Sioux. Significant elevations occurred on F and Scales 4, 6, 8, and 9. Intercorrelations among the acculturation subscales suggested a common dimension underlying social, language, and blood quantum, with values and education/occupation being relatively independent. The social, values, and language subscales were significantly related to validity scales L and F. A preponderance of significant correlations were obtained between values, language, and education/ occupation, and MMPI-168 clinical Scales 2, 4, 7, 8, and 0. These results suggest that caution be used in interpreting the MMPI profiles of Native Americans.
Social Reasoning in IJO Children and Adolescents in Nigerian Communities
Authors: Hollos Marida , Leis Philip E. , Turiel Elliot
Published: March 2007

The study examined moral judgments and concepts of social convention in Ijo communities located in the Niger Delta areas of Southern Nigeria. The main data analyses were based on responses from 46 subjects divided into three age groups: 8-11 years, 12-14 years, and 15-18 years (preliminary data were also obtained in a small village). Assessments were made of judgments about examples of a moral transgression and a breach of social convention. The examples used were based on pretesting for issues relevant to the community. With regard to each type of issue, subjects were asked to evaluate transgressions, provide explanations for their evaluations, and the extent to which punishment should be administered to the transgressors. Subjects were also posed with questions pertaining to the origins and alterability of rules, and authority jurisdiction over the rules. The findings showed differences in subjects' conceptual orientations to moral and conventional issues. Age differences were also found, mainly between the children and adolescents, in the patterns of responses to the various dimensions assessed. The findings indicate that two social conceptual orientations coexist in the Nigerian communities.
Postpartum Depression in the United States and Japan
Authors: Shimizu Yuko Morimoto , Kaplan Barbara J.
Published: March 2007

Nonpsychotic postpartum depression is common in Western culture, but is not widely recognized in Japan. This study investigated the extent of milder postpartum depression in the United States and Japan, and the factors contributing to milder postpartum depression. A total of 21 American and 29 Japanese mothers of newborns filled out the Pitt (1968) Depression Scale and a questionnaire on their backgrounds, feeding style, nighttime sleep loss, contact with adults, life events, social support, women's role concepts, and orientation to work. There were no cross-cultural differences in their depression scores. However, regression equations showed significant differences in the factors contributing to depression. The results are discussed in terms of the cultural differences contributing to depression.
Social Orientation among Israeli Youth a Cross-Cultural Perspective
Authors: Eliram Talila , Schwarzwald Joseph
Published: March 2007

McClintock, Bayard, and McClintock (1983) argue that the more competitive and less cooperative orientation of Anglo-American versus Mexican American children is a product of underlying cultural differences in mediating familial factors such as interdependence, size, and delegation of authority, as well as peer exposure. The cultural distinction between Western and Middle Eastern Jews in Israel displays parallel differences in these socialization factors, thereby offering an opportunity for cross-cultural validation of their model. Knight and Kagan's (1977a) social behavior scale was completed by a sample of 480 students, balanced for ethnicity (Western/ Middle Eastern), age (10-11 / 16-17 years), and ecology (urban/ rural). The central finding was that Middle Easterners were more cooperative than Westerners in rural settings, but not in urban ones. Discussion focused on differential pace of acculturation among rural Middle Easterners and the implication of ethnic differences for educational programming.
Cross-Cultural Agreement in Perceptions of Babyfaced Adults
Authors: McArthur Leslie Zebrowitz , Berry Diane S.
Published: March 2007

Two studies investigated Korean college students' perceptions of babyfaced adults. The first study replicated McArthur and Apatow's (1983-1984) investigation of U.S. students' impressions of schematic adult male and female faces. The second study replicated Berry and McArthur's (1985) investigation of U.S. students' impressions of 20 young adult Caucasian male faces. The studies revealed near perfect agreement between U.S. and Korean subjects regarding the relative babyfacedness of the stimulus persons as well as very strong agreement regarding their traits. The same facial characteristics that were correlated with U.S. subjects' ratings of babyfacedness were also correlated with Koreans' ratings. In addition, like U.S. subjects, Koreans perceived babyfaced stimulus persons to possess more childlike psychological attributes than their mature-faced counterparts. The results are discussed within a theoretical framework that argues that perceptions of babyfaced adults derive from the specieswide adaptive value of analogous reactions to real babies.
Negotiating a Coalition
Authors: Bottom William P. , Holloway James , McClurg Scott , Miller Gary J.
Published: March 2007

The authors examine how negotiators' risk preferences influence the formation of coalitions. Joining a coalition may either increase or mitigate risk depending on the nature of the bargaining problem. In an experimental setting, the authors test whether relative risk preferences influence the likelihood of joining a coalition and the distribution of payoffs in coalitions that form. With inexperienced bargainers, risk preferences predict coalition composition but not payoff distribution. This may reflect the fairly egalitarian agreements reached by these coalitions. With experienced bargainers, risk preferences are unrelated to coalition membership but do predict the distribution of payoffs. Risk preferences influence the course of negotiation in a different manner as parties learn to use both their alternatives and their risk preferences as sources of bargaining power.
Revolutionary Types
Authors: Strauss Harlan J.
Published: March 2007

Most revolutionary elite studies merely discuss and analyze the few key men who build and create revolutionary movements, as well as look upon the "political revolutionary" as a singular, modal type. This paper is a discussion and analysis of the generality of the leadership of one specific political revolution, the 1905 Russian Revolution. By means of Q-factor analysis, it was discovered that the 1905 revolutionary leadership cluster into one of six activity categories or types: (1) rebel, (2) striker, (3) propagandist, (4) party organizer, (5) upper-level politician, (6) intelligentsia. Not only was each type distinct in terms of its revolutionary role, but also unique in terms of childhood, adolescent, and familial characteristics. Moreover, each type, which developed sequentially, parallels the necessary functions of a political system, as specified by Almond and Coleman.
Asymmetry of Payoff Structure and Cooperative Behavior in the Prisoner's Dilemma Game
Authors: Sheposh J.P. , Gallo P.S.
Published: March 2007

This study compares the effect of a standard symmetric Prisoner's Dilemma game and an asymmetric Prisoner's Dilemma game on choice behavior. The two types of Prisoner's Dilemma games were crossed with two sets of payoff matrices, thus generating four experimental conditions. It was predicted that subjects in the asymmetric game condition would manifest less cooperative behavior than subjects in the symmetric game condition. This effect would be due primarily to the significantly lower amount of cooperation for subjects assigned to the low potential reward position. The predicted outcomes were supported. It was concluded that concern with relative outcomes, and in particular concern with being surpassed by other, rather than maximization of own outcomes was the primary motivating factor underlying this finding.
An Experimental Test of a Rationalistic Theory of Deterrence
Authors: Kaplowitz Stan A.
Published: March 2007

An experimental game tested a rationalistic theory of compliance to threats, which assumes the following: (1) The greater the credibility of the threat source the more compliant the target (subject). (2) The credibility of the threat source is determined by (a) the cost to the source of carrying out the threat and (b) the target's knowledge, or lack of knowledge, of the source's behavior in interacting with other threat targets. The theory was clearly disconfirmed. The results can, however, be explained by assuming that subjects regarded the source as violating the norm of equity. Interestingly, the subjects' postgame assessments of how they would have played in other experimental conditions confirm our original rationalistic theory. This suggests that many people assume that to insist on equity is to rationally pursue one's own self-interest.
The Problems of Balancing Reductions in Conventional Forces
Authors: Bellany Ian
Published: March 2007

The problem of how peacetime reductions in "conventional" force strengths on each side of a bipolar balance may be conducted in such a way as not to disturb the stability of the balance, is tackled using a variety of simple mathematical models. Analysis is conducted in general terms but is directed at the current practical problem of the NATO/Warsaw Pact balance in Europe.
Review Section : Nature/Nurture Revisited I
Authors: Nelson Stephen D.
Published: March 2007

Biologically oriented approaches to the study of human conflict have thus far been limited largely to the study of aggression. A sample of the literature on this topic is reviewed, drawing upon four major approaches: comparative psychology, ethology (including some popularized accounts), evolutionary-based theories, and several areas of human physiology. More sophisticated relationships between so-called "innate" and "acquired" determinants of behavior are discussed, along with the proper relevance of animal behavior studies for human behavior. Unless contained in a comprehensive theory which includes social and psychological variables, biolog ically oriented theories (although often valid within their domain) offer at best severely limited and at worst highly misleading explanations of complex social conflicts. The review concludes with a list of several positive contributions of these biological approaches and suggests that social scientists must become more knowledgeable about them.
Perception of Payoff Structure and Opponent's Behavior in Related Matrix Games
Authors: Shubik Martin , Wolf Gerrit , Poon Byron
Published: March 2007

Empirical results indicate to what extent judges recognize similanties between payoff matrices that vary in game theoretic information conditions. Judges failed to note similarities in patterns of payoffs between matrices but did recognize patterns of behavior of an opponent.
Varying Patterns of Reward Cooperation
Authors: Shaw Jerry I. , Thorslund Christer
Published: March 2007

This Prisoner's Dilemma (PD) study explored the "boredom" hypothesis which explains the usual finding of high competition as the outcome of subjects' attempts to alleviate their boredom by trying to outscore one another. Forty male dyads played a 15-trial PD game in which boredom was manipulated by varying both the pattern of rewards sequentially over trials as well as by reward size, real money versus points. As expected, subjects' ratings of boredom were lowest with variable rewards and when playing for money. Cooperation was affected by variable rewards only in the points condition where boredom was highest. However, the same factors which reduced boredom significantly increased interdyad variability. The relationship between this latter finding and the validity of replicated PD games with constant rewards is discussed.
The Bank, the IMF, and the WHO
Authors: Riggs Robert E.
Published: March 2007

Responses to a mailed questionnaire indicate that experience with the World Bank, the IMF and the WHO does not necessarily result in attitudes more favorable to those agencies or to international cooperation. Attitudes tend to be multidimensional, and increased experience is associated with favorable attitudes along some dimensions but not others. Despite functionalist assumptions to the contrary, attitudinal responses to participation in the work of functional agencies do not differ significantly from responses to participation in the more "political" United Nations. Rather, attitudes seem contingent upon the rewardingness of the experience. This, in turn, is affected by the respondent's personal values, his domestic organizational milieu, the nature of the international organization, and the specifics of the respondent's experience. These findings are not totally at odds with functionalist theorizing, but suggest additional variables that functionalism should take into account.
Trends in American Major War and Peace
Authors: Beer Francis A.
Published: March 2007

This article attempts to describe possible historical trends in American major peace and war. With caution, because of the small number of data points, it notes that (a) periods of major peace have become more frequent and shorter; (b) major wars that break up the peace periods have necessarily become more frequent; (c) the length of major wars shows no clear overall trend, though there may be reason to believe that major wars have become more frequent and longer in our own time; and (d) major war casualties appear to have increased absolutely, though not relative to population. These results are compared with possible historical trends in the more general international system, as well as with patterns suggested by probabilistic theory. One explanation for the American experience of peace and war lies in the dynamics of U.S. growth. If one assumes that the apparent trends will continue, the findings finally allow us to extrapolate the scope and limits of future American peace and war.
Alliance and Structural Balance in the International System
Authors: McDonald H. Brooke , Rosecrance Richard
Published: March 2007

Brian Healy and Arthur Stein reached five conclusions about the applicability of international theory to the decade of the 1870s in their essay that was published in the Journal of Conflict Resolution, 1973. We offer data from the 1880s (as well as the 1870s) that extend and modify their work: concluding that there is no net tendency toward structural balance in the international system.
Utilitarianism and the Conflict of Interests
Authors: Moreh J.
Published: March 2007

Utilitarianism has most relevance to “helping behavior” where the agent's action is parametric, that is, the behavior of others can be taken as given. The utilitarian principle has also been applied to strategic behavior, that is, behavior that can be represented by a game. It is shown in this article that the utilitarian objective may conflict with common sense ethics, and where it does not, questions of equity may arise for which Utilitarianism has no answer.

Utilitarian writers have paid scant attention to the games of exchange and externality. In neither of these games does the utilitarian approach agree with our moral intuitions. Apart from this, if all goods either entered into exchange or gave rise to externalities, then the utilitarian solution to these problems would be tantamount to a distribution of welfare that maximized total utility. Such a distribution would be unfair to those who have a relatively low capacity to enjoy goods and to those who suffer negative externalities but impose light ones on others or none at all.
The Military-Industrial Complex
Authors: Mintz Alex
Published: March 2007

Following the conceptual framework proposed by Slater and Nardin (1973) for identifying and judging a military-industrial complex, this article addresses the major features of the Israeli complex (its components, scope of activity, roots, autonomy, motivation, and transition patterns among its heads and influence), considering the extent of the American concept's compatibility with Israeli realities.
Saving and the Fear of Nuclear War
Authors: Slemrod Joel
Published: March 2007

The hypothesis of this article is that the performance and, in particular, the rate of saving in the postwar U.S. economy has been influenced by the changes in the public perception of the threat of a catastrophic nuclear war. An increased threat shortens the expected horizon of individuals, and thus reduces their willingness to postpone present consumption in favor of investment. The hypothesis is tested by expanding a standard savings function estimation technique to include a measure of the perceived threat of nuclear war. Several alternative measures of the perceived threat are considered, based either on the setting of the “doomsday” clock published monthly in Bulletin of the Atomic Scientists, which reflects the editors' judgement about the likelihood of a nuclear conflict, or on an index of the extent of press coverage of nuclear war issues. The tests all support a large and statistically significant impact of the threat of nuclear war on the rate of private saving. These tests are not viewed as conclusive evidence in favor of the economic impact of the perceived threat of nuclear war. Nevertheless, this research suggests that economists may have been overlooking an important source of influence in the postwar, postnuclear U.S. economy. Conceivably, it could affect not only the private savings rate but also other economic variables such as the level of investment in human capital, the level of asset prices, the term structure of interest rates, and the rate of inflation.
Polarity, the Long Cycle, and Global Power Warfare
Authors: Thompson William R.
Published: March 2007

The basic assumptions associated with two approaches to analyzing the relationship between the distribution of capabilities and war, namely Waltz's analysis of systemic stability and Modelski's long cycle of global leadership, are examined and contrasted. The systemic stability model concludes that bipolarity is less likely to be associated with destabilizing warfare than is multipolarity. The long cycle model agrees that multipolarity is the least stable arrangement but it depicts unipolarity as the most stable and least conflictual phase in the system's cyclical concentration/deconcentration process. These arguments are tested empirically by first operationalizing polarity and warfare between global powers for 490 years (1494-1983) and then determining how much warfare is associated with each type of polarity. Aggregating across the entire period, global warfare has been least likely in years of unipolarity and near unipolarity, slightly more prevalent in bipolar years, and much more probable in multipolar contexts. Disaggregating time, however, indicates that bipolarity, in certain periods, can be as destabilizing as multipolarity.
War and American Democracy
Authors: Cotton Timothy Y. C.
Published: March 2007

Most analyses of American elections have treated wars as special events, including them in the analysis, but seeking only to make conclusions specific to each war. This article examines the last five American wars statistically and historically, seeking to demonstrate that, in general, wars have caused elected leaders associated with American entry into battle to lose ground in wartime elections. Both the statistical results and the historical commentary support the central hypothesis and suggest some important related conclusions: Changes in short-run military outlays appear to be the most effective measure of war's impact on the nation; presidents have been more subject to the effects of war than have members of Congress; and wars have influenced postwar elections at least as much as elections during wartime.
Balanced Strategies for Prisoner's Dilemma
Authors: Orkin Michael
Published: March 2007

When is a strategy cooperative, yet safe from invasion? A mathematical characterization of such strategies is given, which I call “balanced.” I show that tit-for-tat is balanced, and, in general, a strategy is balanced if and only if its probability of defection on a particular move is sufficiently large relative to the opponent's cumulative score and sufficiently low relative to its own cumulative score.
Experiments with N-Person Social Traps II
Authors: Rapoport Anatol
Published: March 2007

A version of the Tragedy of the Commons was played by 16 four-person groups, 2 three-person groups, and 1 two-person group. Calculation of individually rational equilibria for the seven-round game was out of the question. The collectively rational strategy, on the other hand, is salient: No one is to draw from the common resource pool for the first six rounds, allowing the pool to double each round; then each is to claim an equal share of the pool, which has increasedby by a factor of 64. The game was presented under two conditions: minimal and full instructions, the latter including the disclosure of the collectively rational strategy. None of the four-person groups and neither of the two three-person groups achieved the optimal result. Only the single two-person group cooperated all the way, refraining from drawing from the pool until the last round and harvesting $38.40 on the final round. This pair was given the full instructions. Full instructions did have a positive effect, however, raising the level of cooperation as measured by several indices.
When Is an Arms Rivalry a Prisoner's Dilemma?
Authors: Lichbach Mark Irving
Published: March 2007

This article uses the utility functions from Richardson arms rivalry (R-AR) models to help determine the equilibrium outcomes of 2 × 2 game-theory arms rivalry (GT-AR) models. Three different formulations of a R-AR, one general and two specific, are employed. Four different formulations of a GT-AR, a PD arms rivalry (PD-AR), a Chicken arms rivalry (Chicken-AR), a Deadlock arms rivalry (Deadlock-AR), and a Stag Hunt arms rivalry (Stag Hunt-AR), are also used. I first establish the most general possible restrictions on Richardson-type utility functions that determine the four common 2 × 2 arms rivalry games. I then establish two counterintuitive results: One of the specific formulations of a R-AR may help imply the equilibrium outcomes of a PD- or Deadlock-AR but is inconsistent with the equilibrium outcomes of a Chicken- or Stag Hunt-AR; it is impossible for either specific formulation of a R-AR to ever yield the equilibrium outcome of a Stag Hunt-AR.