bluuebunny/crossref_metadata_2025 huggingface dataset:
A Normal Stress Criterion for Crack Extension Direction in Orthotropic Composite Materials
Authors: Buczek M.B. , Herakovich C.T.
Published: March 2007

A criterion for predicting the direction of crack extension in orthotropic composite materials is presented. The criterion is based upon the normal stress and the anisotropic tensile strength on arbitrary planes about the tip of a crack. Results are ob tained, via finite element solutions, for: (a.) isotropic mixed mode fracture, (b.) cracks in unidirectional off-axis slotted composite tensile coupons and (c.) cracks in cross plied laminates. Comparisons are made with other theories and experimental results.
Thermally Induced Stresses and Deformations in Angle-Ply Composite Tubes
Authors: Hyer M.W. , Rousseau Carl Q.
Published: March 2007

The effects of a uniform temperature change, from cure, on the stresses, axial expan sion, and thermally-induced twist for four specific angle-ply tube designs are considered. The study was conducted in the context of using tubes as major structural components in space structures. The four designs are: ( + Ø/ - Ø/040/ - Ø/ + Ø); (+ Ø2/040/- Ø2) ( + Ø2/ - Ø2/040); and (0 40/ + Ø2/ - Ø2). All tubes have off-axis fibers for holding the axial layers together and for providing some measure of torsional rigidity. All four designs have the same volume fraction of off-axis layers. In addition to considering smgle material tubes made of P75s/934, hybrid tubes using T300/934 in the off-axis layers and P75s/934 in the axial layers are studied. The stresses and deformations in the tubes are studied as a func tion of the four designs, the off-axis angle, and as a function of single-material and hybrid construction. The torsional and axial stiffnesses of the tubes are also computed. The study concludes that tube design has a minor influence on the stresses, axial stiffness, and axial thermal expansion. These are more a function of off-axis angle and material selection. On the other hand, because of the position of the + Ø and - Ø layers, both relative to each other and relative to the center of the tube, tube design does influence thermally-induced twist and torsional stiffness. None of the above designs is free of thermally-induced twist. In addition to tube design, the off-axis angle and material selection also influence thermally-induced twist and torsional stiffness.
Mode II Cyclic Delamination Growth
Authors: Trethewey Bruce R. , Gillespie John W. , Carlsson Leif A.
Published: March 2007

The end notched flexure (ENF) specimen is employed in an investigation of the inter laminar fracture of unidirectional graphite/epoxy, graphite/polyimide, and graphite/PEEK composites subjected to Mode II fatigue loading. Fatigue crack growth rates are deter mined for the stable delamination growth observed under fully reversed cyclic loading. Within the crack driving force range studied, cyclic crack growth data obeyed a power law dependency on the cyclic strain energy release rate. The response of the various material systems is compared to crack growth under static loading. The importance of the data re duction scheme for the crack growth resistance is discussed. Friction is examined as a potential energy absorbing mechanism in the test by finite element analysis. Suggestions for appropriate experimental geometries minimizing frictional effects are presented. Finally, fatigue fracture surfaces are analyzed with scanning electron microscopy to identify crack growth mechanisms.
A Note on the Thermal Conductivity of Filled Polymers
Authors: Padilla A. , Sanchez-Solis A. , Manero O.
Published: March 2007

The thermal conductivity of a composite formed by sand fillers embedded in a poly ethylene matrix is studied experimentally. Results show a region of low particle content, where the conductivity is predicted by Maxwell-Eucken equation. Only at very high par ticle content, the filler tends to form agglomerates and conductive chains. On this region, it is shown that the thermal conductivity of the two-phase system formed by coarse and ir regular particles can be predicted by the conductive chain model.
Crystal Formation on Graphite/Polymer Composites
Authors: Tucker Wayne C.
Published: March 2007

Two graphite/polymer composites were directly coupled with mild steel and immersed in natural seawater for intervals up to three months. Ensuing crystal growth in the form of aragonite was observed on both composites. It is proposed that local changes in the environment by corrosion processes were responsible for the crystal formation.
A Technique for Predicting Molding Conditions which Result in Class A Surfaces for Glass Fiber Reinforced Polymers
Authors: Kia Hamid G.
Published: March 2007

This work is a continuation of our modelling studies which are aimed at predicting the appearance of glass fiber reinforced polymers. The mathematical model which has been developed was presented earlier [2,3]. In this study, the following two parameters were evaluated: 1—The effective thickness of fiber strands which is different from their apparent thickness and is an indication of clustering (bundle formation) of the strands; and 2—The slope of surface deformation pertinent to smooth surfaces.

From the experimental results, the effective thickness of fiber strands was determined to be 0.35 mm. This value does not appear to be dependent on the type of fibers, type of resin, or fiber content, within the range of the materials and molding conditions used in this study.

To obtain a definition for surface smoothness, the slope of surface deformation (0) is related to the smoothness of the surface. It is found that 0 = 0.006 relates to smooth sur faces on glass fiber reinforced polymers.

Applying the above two values along with our mathematical model, graphic relation ships are derived which can predict the thickness of the top layer needed to produce a smooth surface.
Interlaminar Shear Moduli of Cross-Ply Laminates: An Experimental Analysis
Authors: Post D. , Dai F.L. , Guo Y. , Ifju P.
Published: March 2007

A whole-field micromechanical deformation analysis was performed on a thick [902/0] n graphite/epoxy laminate. Rail-shear loading conditions were used and deformations were measured by high-sensitivity moire interferometry. Shear strains were determined in in dividual plies and in the resin-rich zones between plies. Nominally equivalent plies exhibited dramatic differences in shear strains. Large shear strains occurred in the resin- rich zones. Relationships were developed to extract average or representative strain values and shear moduli were calculated from these. Effective interlaminar moduli, for design purposes, are given for 0 deg and 90 deg plies as G 13 = 3.2 GPa (470,000 psi) and G23 = 2.4 GPa (350,000 psi), respectively, and for the laminate as G = 2.7 GPa (390,000 psi).
Increasing Strength of Graphite/Epoxy Bolted Joints by Introducing an Adhesively Bonded Metallic Insert
Authors: Nilsson Sören
Published: March 2007

In this paper a method to increase the failure load in graphite/epoxy bolted joints where the failure mode is bearing strength is proposed by bonding a metallic insert in the hole. In order to design test specimens with significantly reduced compressive stresses at the hole boundary, finite element (FE) analysis was performed. The FE analysis revealed the possibility to reduce the compressive stresses at the hole boundary in quasi-isotropic laminate by approximately 50%, if a 10 mm hole is enlarged to 14 mm and a 2 mm thick metallic insert is adhesively bonded in the hole. Experimental results showed an increased failure load of up to 55% when using an aluminum insert and 30% when using steel insert, the steel insert also giving a 13 % stiffer joint. The adhesively bonded insert altered the failure mode to failure in the adhesive combined with net tension of the composite member.

Further studies of FE-results explained the difference in failure load when using a steel or aluminum insert respectively by the fact that the stiffer steel insert causes higher tension stresses in the adhesive, which apperently leads to a primary tension failure in the adhe sive.
On the Bearing Strength of Bolted Graphite/Epoxy Laminates
Authors: Eriksson Ingvar
Published: March 2007

One of the basic failure modes of bolted composite laminates is bearing fail ure. This mode of failure occurs in the material immediately adjacent to the contact points of bolt and laminate, and is caused primarily by compressive stresses acting on the hole boundary. The results of an experimental program which measured the bearing strengths of two different types of graphite/epoxy specimens are presented. The influence on the bearing strength of several important parameters including lateral constraint and ply orien tation are shown. Strains were measured in the vicinity of the loaded hole to quantify the extent of bearing failure. A new approach to predicting bearing failure is outlined. The Delamination Buckling Model (DBM) assumes that ply buckling following delaminations is a major feature of bearing failure. Quantitatively good agreement was found between ex periment and model results.
Effects of Hydrostatic Pressure on the Torsional Shear Behavior of Graphite/Epoxy Composites
Authors: Shin E.S. , Pae K.D.
Published: March 2007

The torsional shear stress-strain behavior of a graphite/epoxy composite material and also the epoxy matrix material alone has been determined at various hydro static pressures up to 6 kbar, using a newly constructed high pressure torsion apparatus. The composite samples were machined into thin walled hollow cylinders from press molded and oven cured, laminated panels. Graphite fibers of the samples were continuous, (0°) uniaxial, and 60% by volume.

The normally linear elastic shear stress-strain curve of the epoxy matrix material at at mospheric pressure shifted upwards with pressure and showed nonlinearity at 2 kbar and higher. The shear modulus (G ) and the fracture strength ( τf) and strain (γ f) all increased markedly and bilinearly with a break occurring at 2 kbar. The shear stress-strain curves of the composite material showed dramatic changes from an almost linear curve with γ f of 8% at atmospheric pressure to a nonlinear curve, exhibiting yielding, work-hardening, and extensive drawing with γ f of 57 % at 6 kbar. The G increased bilinearly with pressure from 10.7 x 10 8 at atmospheric pressure to 12 x 108 N/m2 at 6 kbar with a break also occurring at 2 kbar. The work hardening parameter, x, determined at 1% offset strain in creased significantly with pressure. The τf and γ f also increased linearly with an abrupt jump occurring between 4 and 5 kbar as the mode of fracture changed from delamination to shearing.
An Impregnation Model for the Preparation of Thermoplastic Prepregs
Authors: Bafna S.S. , Baird D.G.
Published: March 2007

The penetration of the polymeric melt into the fine interstices (typically of the order of a few microns or less) between the fibers of a thermoplastic prepreg depends upon the shape, volume fraction and geometry of packing of the fibers, the rheology of the polymeric melt and the interfacial surface tension. A model for preimpregnation would help determine optimal processing variables. In this paper the methods currently used to prepare thermoplastic prepregs are briefly reviewed and a preimpregnation model (which is generic to most processes involving melt impregnation) for describing the flow of resin into fiber-tows is developed. Such flows are usually modelled using Darcy's Law, but the approach of this paper represents an improvement in that empirical parameters (like permeability) are not required and detailed flow profiles can also be calculated. The effect of different geometries of packing on processing variables (fiber spacing, impregnation time, pressure drop) and flow characteristics (velocity, planar elongation and shear rates) is calculated. The fiber spacing (which depends upon the fiber volume fraction and geom etry of packing) has been found to be a critical parameter. The degree of shear-thinning of the polymeric melt on the pressure drop during flow through reinforcement is found to be very significant. Numerical values for the various flow and processing variables are calculated based upon experimental data reported in the patent literature. The value of the model is that it lets one predict the processing parameters required to completely impreg nate the tow and whether effective impregnation is feasible for a given polymer- reinforcement system.
The Effect of Strain Rate on Damage Mechanisms in a Glass/Polypropylene Composite
Authors: Kander R.G. , Siegmann A.
Published: March 2007

Changes in damage accumulation and energy absorption were studied as a function of strain rate in a glass reinforced polypropylene composite during uniaxial ten sile testing. The polypropylene matrix was reinforced with long discontinuous glass fibers, and was manufactured using a du Pont proprietary wet-forming process. Acoustic emission monitoring was combined with mechanical testing and microscopic observation to study details of the damage accumulation process. Maximum stress, strain at maximum stress, and energy absorption capability all increased with increasing strain rate. Mechanical re sponse, acoustic emission signatures and micrographs of the fracture surfaces all showed a strain rate dependent transition in failure mechanism. Results show that the "apparent" fiber-matrix interface properties changed as a function of strain rate, and were closely coupled to the balance between the time scale of fiber pull-out and the characteristic time scale of resin deformation. Also, a systematic change in total energy absorption capability was used to demonstrate the competition between specific energy absorption (i.e., per unit volume) and the size of the damage zone.
Toughness of Reinforced Ductile Thermoplastics
Authors: Vu-Khanh T. , Denault J.
Published: March 2007

Fillers and reinforcements are widely used to enhance the strength and rigidity of plastics. These improvements are often obtained at the expense of toughness. This paper discusses the effects of major material parameters such as concentration and shape of the reinforcement, matrix morphology, and interfacial strength on the toughness of two reinforced ductile thermoplastics, namely polypropylene and PET/PBT blend. The toughness of these composites is strongly governed by the competition between shear yielding and crazing in the matrix. It has been shown in previous work that shear yielding occurs around the reinforcement, due to the debonding at the reinforcement/matrix inter face, and results in a stretching effect of the matrix which leads to an increase in the crack growth resistance of the composite. Crazing occurs in the matrix and dissipates much less energy. This paper demonstrates that the reinforcement content can be optimized in order to maximize the matrix stretching. The interfacial strength affects the stress distribution in the matrix and consequently the magnitude of shear yielding and crazing. The dimensions of the reinforcement are another major parameter in the fracture process. Two- dimensional fillers (flakes) behave the same as three-dimensional fillers (spheres), and for these classes of reinforcement, a unique qualitative relationship between the maximum crack growth resistance and the average distance between the surfaces of two adjoining particles has been observed, regardless of the nature of the filler. In the case of fibers, there is a critical fiber length which results in lowest crack growth resistance. Below the critical length, the matrix stretching is dominant and above the critical length, fiber pull- out enhances the dissipation of energy in the fracture process.
On the Failure Work and Modulus of Composites Reinforced by Thin Elastomer-Coated Fibers
Authors: Jao Shyh-Hua , Stress Technology Inc.  , McGarry Frederick J.
Published: March 2007

Fiber reinforced composites have high specific strength, excellent fatigue resistance and variable directional freedom in property control, allowing for optimal structural design. A deficiency in stiff fiber reinforced composites is poor low-speed im pact resistance (i.e., low energy absorption before major failure). This has been ex perimentally shown to be remediable by coating the reinforcing fibers with an elastomeric coating. However, the stiffness of the composites is decreased because of reduced effi ciency in interface load transfer in the soft coating. This can be improved by making the coating very thin. For practical design, it is necessary therefore to provide an analytical relation between the increase in failure work and the corresponding decrease in stiffness with the coating properties. Interface stress concentration is parametrically studied in this paper. A formula for calculating the longitudinal modulus of composites reinforced by aligned coated fibers is proposed. The formula is based on a combination of both compos ite mechanics and finite-element stress analysis. The results provide fundamental guide lines to practical engineering applications of composites of elastomer-coated fibers.
An Experimental and Analytical Investigation of Composite Drive Shafts with Non-Circular End Cross-Sections
Authors: Gross Robert S. , Goree James G.
Published: March 2007

An optimization methodology is presented for the selection of the end cross-sectional shape of composite torque tubes (drive shafts) with noncircular end geometries. In a typical application, metal inserts are adhesively bonded in the ends of the tubes to allow for torque transmission. The worst case scenario of bond failure with subse quent torque transmission via insert-tube contact is considered. Optimization of the tube end cross-sectional shape under this worst case situation is the goal of this study. Employ ing facets of elasticity and the finite element method, a two step methodology is estab lished to predict the failure torque of a tube with a range of selected end cross-sections. This methodology is verified through comparison with experimental data. Results ob tained from the analytical and experimental studies indicate a spline-like cross-sectional shape as the optimal design. Failure torques on the order of 70% of the circular cross- sectional failure torque are shown to be possible.
Ethnic Affirmation Versus Cross-Cultural Accommodation
Authors: Bond Michael H. , Yang Kuo-Shu
Published: March 2007

Chinese bilinguals from Hong Kong responded to three different question-naires in their first or second language of Chinese or English. On some questionnaire items their answers to the English version differed from those to the Chinese version in a more "Western" direction (cross-cultural accommodation); for others, in a more Chinese direction (ethnic affirmation). These outcomes were unaffected by the respondents' level of identification with traditional Chinese culture or by their degree of anonymity vis-a-vis the experimenter conducting the research. An internal analysis of responses to the Rokeach Value Survey revealed that the more important the value to the respondent, the less likely they were to show cross-cultural accommodation. It thus appears that affirmation occurs on important issues in order to buttress the individual's of psychological distinctiveness from other groups (Tajfel, 1974a); compromise is possible on less important matters, presumably more peripheral to the individual's cultural self-concept.
Constructing Complex Geometric Patterns
Authors: Osuji Oluigbo Nathan
Published: March 2007

This study was designed to determine the ability of Igbo children of varying ages to construct geometric patterns of varying complexity, and to compare the performance with those of their counterparts in North American countries. Results indicate a developmental pattern with a highly significant interaction between age and pattern complexity. Differential performance among the various age groups was greatest at medium- and high-level pattern complexity. Comparison of the pattern performance of the Igbo subjects with those of their Canadian counterparts, as reported by Halford and Macdonald (1977), showed striking similarities. The Igbo children, however, tended to achieve the ability at a slightly younger age.
A Study of Person Perception in Nigeria
Authors: Boski Pawel
Published: March 2007

A critical appraisal of the existing motivational and cognitive approaches to attribution led to a postulation of a two-dimensional model consisting of Locus of Causality and Evaluation. Consequently, two attributional mechanisms were hypothesized to be operating: egotism and positive evaluation. In the study, a person's ethnicity was regarded as a factor affecting the degree of egotism in self-attributions, while an interaction of ethnic variables was predicted to determine the magnitude of positive evaluation in actor's attribution. The modelwas tested with Hausa, Ibo, and Yoruba Nigerian undergraduate students serving as subjects in a three-way experiment (with target object of perception being the fourth and repeated measures factor). As expected, the Muslim Hausas demonstrated less attributional egotism than the Christian southerners. Other-attributions did not reveal the predicted pattern of a positive evaluation gradient along the psychological distance from the self. The findings demonstrated, however, a strong egocentric tendency in other-attribution due to self-outcome; and here, too, the Hausa subjects showed a unique resistance against this motivational bias.
A Preliminary Culture-Specific Personality Scale
Authors: Spinks Peter Milner
Published: March 2007

In order to develop a preliminary anxiety scale specifically for South African Indians, newly derived anxiety responses and those from existing instruments were included in a 70-item questionnaire along with a self-rating scale. Results suggest that some new items are more appropriate for Indian Ss than those from Western scales, and factor analyses confirm the multidimensionality of trait anxiety for this population. Using item and factor analytic criteria, 17 responses are selected from general tremor weakness, cognitive, somatic, and activity dimensions.
How are Responses to Verbal Insult Related to Cultural Collectivism and Power Distance?
Authors: Bond Michael H. , Wan Kwok-Choi , Leung Kwok , Giacalone Robert A.
Published: March 2007

It is assumed that an act is construed as aggressive and the actor thus negatively evaluated when that act falls outside legitimate modes of social control. If true, then cultural variations in the use of social control should be related to perceptions of an insult and of the insulter. In a scenario study, responses of Hong Kong Chinese, who are high in collectivism and power distance, were compared with those of Americans, who are low in collectivism and moderately low in power distance. In confirmation of this reasoning, the Chinese were found to be less critical of an insulter and of his or her action as long as he or she had higher status than the in-group target. Americans made no consistent distinctions as a function of the insulter's status or group membership.
Stress and Distress
Authors: Dyal James A. , Chan Carolina
Published: March 2007

Frequency and intensity of stressful life events (SLE) and distress (neurotic symptom formation and anxiety) were compared in groups of Chinese students at the University of Hong Kong, Chinese student sojourners at a Canadian University, and Euro-Canadian students. The results are dominated by a strong Gender X Culture interaction for the total symptom score such that Chinese females, especially female sojourners, are most at risk. There were no cultural or gender differences in SLE frequency. However, the possible differential utility of the SLE measures as predictors of psychological distress was highlighted by the fact that SLE frequency was positively related to symptoms for Canadians and University of Hong Kong students but not for student sojourners for whom the best predictor of symptoms was SLE impact; furthermore, the relationship was negative. Female sojourners appear to have a different stress-symptom structure than male sojourners or female Chinese at the University of Hong Kong.
Cultural Collectivism and Distributive Behavior
Authors: Leung Kwok , Iwawaki Saburo
Published: March 2007

Leung and Bond (1984, Study 2) found that Chinese subjects tended to sacrifice their self-gain to benefit in-group members in allocating a group reward, whereas American subjects did not show this tendency. This cultural difference was interpreted as consistent with a framework of cultural collectivism. The present study provides a stricter test of their framework by comparing two different oriental groups with American subjects, and by measuring subjects' levels of collectivism directly. Japanese, Korean, and American subjects read a scenario in which an allocator worked with either an in-group or an out-group member. The allocator had either a low or a high input and used either the equity or equality norm to divide a group reward. Japanese and American subjects also responded to a collectivism scale. Results indicated that although the effects involving culture were not significant, and thus did not replicate the findings reported by Leung and Bond, the overall results were still consistent with their framework. Other effects replicated earlier findings, and collectivism was correlated with the tendency to use the equality norm. Possible explanations for results were discussed.
Why Do They Do It Like This?
Authors: Bercovitch Jacob , Houston Allison
Published: March 2007

Studies of international mediation traditionally have focused on the impact and effectiveness of mediation. This study examines mediator behavior and evaluates the factors that influence mediators' behavior and choice of strategies. Three contextual dimensions that exert influence on mediator behavior are preexisting factors (the conflict context and identity of the parties), concurrent factors (the identity of the mediator and actual mediation event), and background factors (the effect of information from previous mediation efforts). An original data set of 295 international conflicts from 1945 to 1995 is used to test a contingency model of mediation behavior. The results of a multivariate analysis suggest that the conditions of the mediation environment and the identity of the parties in conflict are the most significant influences on mediator's choice of strategy.
Responses to Media Coverage of Terrorism
Authors: Slone Michelle
Published: March 2007

Differential anxiety responses to television coverage of national threat situations and terrorism in Israel were examined. A total of 237 participants were evenly divided into two groups, each exposed to an experimental or control condition. The experimental condition involved exposure to television news clips of terrorism and threats to national security. The control condition involved equivalent-length exposure to news clips unrelated to national danger situations. Results supported the anxiety-inducing effect of the experimental condition and indicated differential demographic and dispositional responses to the footage according to gender, religiousness, and level of dogmatism. These results support the powerful effect of the mass media and advocate further exploration of links between media broadcasting of political violence and psychological processes.
Conflict without Misperceptions or Incomplete Information
Authors: Garfinkel Michelle R. , Skaperdas Stergios
Published: March 2007

Conflict and war are typically viewed as the outcome of misperceptions, incomplete information, or even irrationality. The authors show that it can be otherwise. Despite the short-run incentives to settle disputes peacefully, there can be long-term, compounding rewards to going to war when doing better relative to one's opponent today implies doing better tomorrow. Peaceful settlement involves not only sharing the pie available today but also foregoing the possibility, brought about by war, of gaining a permanent advantage over one's opponent into the future. The authors show how war emerges as an equilibrium outcome in a model that takes these considerations into account. War is more likely to occur, the more important is the future.
Looking for Audience Costs
Authors: Schultz Kenneth A.
Published: March 2007

The methodological issues that arise in testing Fearon's argument about domestic political audience costs and signaling in international crises are examined, in particular the difficulty of finding direct evidence (1) that escalating a crisis and then backing down jeopardizes a leader's tenure in office, and (2) that democratic leaders are more vulnerable to removal in this event than are nondemocratic leaders. Tests that seek to measure the existence and magnitude of audience costs encounter severe problems of partial observability and strategic selection: the effect of audience costs on a leader's political survival can only be detected by looking at cases in which the costs are actually incurred, but strategic choice implies that the probability of incurring audience costs is a function of their value. A formal model, brief case studies, and Monte Carlo simulations are used to show that these problems bias direct tests against supporting either of the audience cost propositions. Tests based on observed audience costs understate both the mean level of audience costs in the full population and the difference in means across regime types.
Do Ethnic and Nonethnic Civil Wars Have the Same Causes?
Authors: Sambanis Nicholas
Published: March 2007

A booming quantitative literature on large-scale political violence has identified important economic and political determinants of civil war. That literature has treated civil war as an aggregate category and has not considered if identity (ethnic/religious) wars have different causes than nonidentity wars. The author argues that this is an important distinction and that identity wars are due predominantly to political grievance rather than lack of economic opportunity. Ethnic heterogeneity is also associated differently with identity than nonidentity wars. Some systemic variables are also important determinants of civil war, and these have been neglected in the existing literature. An important new result is that living in a bad neighborhood, with undemocratic neighbors or neighbors at war, significantly increases a country's risk of experiencing ethnic civil war.
International Conflict as a Decision System
Authors: Moll Kendall
Published: March 2007

Recent conflict studies that combine the behavioral decision-making approach with quantitative systems theory are yielding new insights and new verification methods in policy analysis. They can be characterized as "decision system" studies. The present study proposes and quantitatively verifies several hypotheses about how the British Navy budget was decided over a seventy-year period before World Wars I and II. It concludes that actual decisions can be very precisely modeled in terms of an arms budget race with goals that shifted intermittently due to (a) changes in the countries identified as antagonists, and (b) changes in relative aspiration levels. The levels and changes of goals are validated by reference to known historical incidents. Although technological and strategic military factors were prominently discussed in public debates, they had little direct influence on budget levels. Similarly, domestic economic and political party factors were often mentioned in connection with the naval budget, but the model shows that they were only occasionally influential.
Boundary Role Conflict
Authors: Druckman Daniel
Published: March 2007

The boundary role conflict suggests two types of functions in negotiations: monitoring the other side for evidence of movement and monitoring one's own side for evidence of preferences. These functions differ in terms of focus and information-processing. This paper addresses these functions in terms of two general models, referred to as the negotiator as bargainer and the negotiator as representative. The negotiator-as-bargainer model assumes responsiveness between opposite-number negotiators. Two versions of this model showed that responsiveness can be based on both one's own previous concessions and the other's concessions or it can be a more complex function of expectations and evaluations. Each of the versions was supported in part by the data which suggested that these may be early and late processes in negotiation. The negotiator-as-representative model assumes responsiveness between the negotiator and his constituents. Such responsiveness is depicted in the form of a utility model where the negotiator attempts to balance n-components of value in the process of building a package. He is concerned with maximizing the value of the package in terms of both his own and his constituents' priorities. Experimental results suggest that the model accounts for a significant portion of variance in actual decisions. Finally, implications are drawn toward a reconceptualization of the boundary role conflict.
Competing Norms of Distribution in Coalition Games
Authors: Roth Byron M.
Published: March 2007

Most social psychological studies of coalition formation involve the assignment to subjects of different quantities of some resource such as weights or votes. Most coalition theories assume that these resources, or "sources of entitlement" as they are referred to here, call into play appropriate norms of distribution (such as parity) which determine the outcome of the game. There has been, however, little work on the effect of the competition of such norms when individuals may make competing claims on the basis of the possession of different sources of entitlement. The research reported here represents an initial attempt to assess such effects. Subjects in a three-person coalition game were asked to act as representatives of groups which differed in size, the collective effort of its members, and its ability to increase the total payoff to a coalition. Two studies are reported; one employed responses to a questionnaire, and the second involved role-playing by participants. The results of the questionnaire supported the hypothesis of strength in weakness for the effort and size factors, but those results did not, in general, carry over into the experimental bargaining. In neither study did weakness in economic entitlement benefit a subject. It was concluded that the strength in weakness hypothesis has limited applicability and seems to apply only in those cases where an actor's weakness can be effectively translated into a benefit for a potential partner. Minimum resource theory was seen to be a special case of that hypothesis.
External and Internal Conflict Behavior Among Nations, 1966-1967
Authors: Eberwein Wolf-Dieter , Hübner-Dick Gisela , Jagodzinski Wolfgang , Rattinger Hans , Weede Erich
Published: March 2007

In this article we attempt to replicate the hypothesis tested by Rummel and others that external and internal conflict are unrelated. We do this using data for 125 nations for the years 1966-1967. As did Rummel, we use exploratory factor analysis and regression analysis; in addition, we also employ confirmatory factor analysis. Results from confirmatory factor analysis contradict Rummel and reveal moderately strong correlations between internal and external conflict factors. Regression analysis and partial correlations, however, show that zero-order cross-country correlations between internal and external conflict are reduced to insignificance when a control variable, population size, is introduced in the analysis.
The Guns of November
Authors: Stoll Richard J.
Published: March 2007

A number of recent studies have investigated relationships between the presidential election cycle and the implementation of various policies. This article falls in this tradition, and asks whether a link exists between the reelection efforts of presidents, and the visible use of military force by the United States. After outlining why, and under what conditions, such a connection can be expected, a multivariate statistical model is tested for the time period 1947-1982. Despite the presence of several control variables, the results indicate that there is a connection, with fewer visible uses of force associated with presidential reelections in peacetime, and a slight increase in uses of force associated with presidential reelections during wartime.
Participation in Conferences, Treaties, and Warfare in the European System, 1816-1915
Authors: Faber J. , Weaver R.
Published: March 2007

Intergovernmental cooperation in Europe has been operationalized by the number of participants in intergovernmental conferences and treaties. These data have been decomposed into two groups, one group containing the number of participants in conferences and treaties on war-related issues and the second containing the same data on peace-related issues. By applying time series analysis to these data sets and to data sets containing the number of participants in warfare and the number of nation-months of warfare, the neutralizing effects of both sets of data on conferences and treaties has been confirmed. An increase in the number of participants in conferences and treaties on war-related issues increased the number of participants in warfare, and vice versa. A large number of participants in conferences and treaties on peace-related issues decreased the number of participants in warfare, whereas the inverse relationship was positive; that is, the number of participants in conference and treaties on peace-related issues increased due to the large number of participants in warfare.
The Optimal Level of Generosity in a Selfish, Uncertain Environment
Authors: Molander Per
Published: March 2007

The tit-for-tat strategy in iterated prisoners' dilemma games is examined in the presence of disturbances. It is shown that performance deteriorates drastically at arbitrarily low noise levels. The situation may be remedied by introducing some unconditional generosity. This may be done without exposing oneself to the risk of exploitation by the other party.
The Contagion of Political Conflict in Africa and the World
Authors: Hill Stuart , Rothchild Donald
Published: March 2007

In this article we seek to specify and measure the paths by which domestic political conflict can diffuse across state boundaries. By focusing on data for Africa and the world from 1962 to 1966 and 1971 to 1975 we have found that receptivity to outside political conflict is contingent upon a recent history of domestic strife and will increase if a society is polarized among a few contending groups. In those countries where the mass media come under central political control, a greater level of media development will slow the spread of conflict by offering political elites an important means by which to control the information available about outside discord.
The Information Dilemma
Authors: Keck Otto
Published: March 2007

Information asymmetries persist because in certain situations the value of information cannot be appropriated by the one who has it. A game-theoretic model of information asymmetries is presented, showing that under certain conditions there exists a prisoner's dilemma. The model is used to clarify the failure of markets to transmit certain types of information, to explain policy failure in regulation without recourse to government failure, and to identify new types of transaction failure in hierarchy and politics.
Long Waves in War, Production, Prices, and Wages
Authors: Goldstein Joshua S.
Published: March 2007

This article summarizes the main empirical findings of a research project on long waves of roughly 50 years length in political/economic life. The statistical analysis of 40 historical economic time series, along with data on great power wars, indicates that war plays a central role in the long wave, that “stagflation” can be seen as a phase of the long wave, and that war dampens economic growth. Since 1495, long waves are identified in great power war severity and in internationally synchronized trends of prices and real wages. Weaker long waves are found in world production since 1750, these phases leading the war phases by about a decade. A theoretical model consistent with these lagged correlations among variables is elaborated. Long waves are seen as arising from a two-way causality between war and economic growth.
The Domestic and Foreign Policy Beliefs of American Leaders
Authors: Holsti Ole R. , Rosenau James N.
Published: March 2007

The relationship between our leaders' beliefs about domestic and foreign policy issues has generated a lively controversy. Much of the existing literature indicates that there is a very limited correlation between them. This article is based on data derived from a 1984 survey in which 2,515 American leaders filled out and returned a lengthy mail questionnaire. Respondents are classified according to their positions on both foreign policy scales (hard liners, internationalists, isolationists, accommodationists) and domestic policy scales (economic liberals, social liberals, economic conservatives, social conservatives). The data reveal a strong and consistent relationship between domestic and foreign policy beliefs. Analyses of the leaders' background attributes indicate that ideology, party, and occupation are strongly correlated with both sets of beliefs, whereas education, age, military service, travel experience, and gender are weakly related to beliefs. The conclusion raises some questions about the implications of the findings.
Value Differences and Conflict Resolution
Authors: Druckman Daniel , Broome Benjamin J. , Korper Susan H.
Published: March 2007

Three conditions are compared for their effects on attempts to resolve differences on issues concerning both values and interests. Two of the conditions were designed to facilitate resolutions in different ways: One reflected the “values-first” approach while the other allowed the parties to concentrate on their interests apart from differences in values (“interests-first”). Both approaches produced more resolutions and more improved perceptions of the negotiating climate than a third condition in which interests derived directly from values that were not the focus of prenegotiation exercises designed to increase understanding. However, the processes by which dyads in the two conditions achieved resolutions differed. Dyads in the values-first condition were more cooperative in the discussions from their initial positions than were those in the interests-first condition. Implications of these results for models of negotiation and for long-term intergroup cooperation were discussed along with suggestions for further analytical work.
Bargaining about Bargaining
Authors: Toit Pierre Du
Published: March 2007

The problem of specifying the empirical conditions of, and prescriptive guidelines for, conflict resolution in deeply divided societies such as South Africa presents a challenge to both political theorists and public policy makers. The aim of this article is to assess the prospects for conflict resolution in South Africa by evaluating two divergent theoretically informed predictions for South Africa. I draw on aspects of bargaining theories that describe the nature of the so-called bargaining problem. I conclude that successful conflict resolution in deeply divided societies such as South Africa depends on how contending political leaders respond to the constraints inherent in conflicts characterized by strategic interaction.
Predicting Soviet Military Intervention
Authors: Kaw Marita
Published: March 2007

This article attempts to explain and predict Soviet intervention in conflicts abroad during 1950-1987. I constructed a geopolitics driven model of Soviet calculus for intervention to predict which of four levels of intervention will be undertaken: verbal/diplomatic or less, arms delivery, limited personnel, or large-scale personnel support. When tested on 403 diverse civil and interstate conflicts adapted from the Correlates of War and Conflict and Peace Data Bank projects, the model proved correct in 88% of the cases. Two other predictive rules — the Modal and the Mirror Image alternatives — were also tested and used as baselines for comparison. The results show Moscow rarely wields the sword except to rescue an embattled ally or a potential client. Although it intervened more frequently during the 1970s, an increase in the number of beleaguered clients seems to account for the trendline. The findings offer useful correctives to Cold War and Mirror Image theories.
Conflict Management in Mature Rivalry
Authors: Kuenne Robert E.
Published: March 2007

Rivalry is a form of conflict in which relatively few opponents must make decisions in full knowledge that rivals will perceive those decisions as interfering to a greater or lesser extent with their welfares. Actors' autonomous actions must be undertaken only after opponents' potential reactions have discounted the favorable effects on the initiating agent's welfare in the absence of such reactions. This paper defines an environment of mature rivalry in which this prospective interaction of decisions takes place in a manner that restrains conflict through the fostering of mind-sets, institutions, and conditions that enhance cooperation. The role of uncertainty is featured as a facilitator of these stabilizing tendencies. A formal framework for analyzing the solution process in contexts of mature rivalry is presented using the theory of rivalrous consonance.
Soviet Academic Theories on International Conflict and Negotiation
Authors: Zisk Kimberly Marten
Published: March 2007

The influence of Soviet international relations scholars on Soviet foreign policy has grown markedly in recent years. The ideas about international conflict and cooperation that Mikhail Gorbachev has expressed in his writings and speeches reflect the views of those scholars, and as individuals they have been drawn directly into the policy-making process. This article summarizes the emerging Soviet academic consensus about the need for joint, peaceful solutions to international environmental and security problems, and then discusses five particularly interesting theoretical approaches taken by subgroups of Soviet scholars to the problem of international conflict resolution. The author concludes that, while debates over specific theoretical approaches and state policies continue among Soviet scholars, they have adopted a new common framework for analyzing international conflict and cooperation; the old framework of class struggle has been replaced by a worldview that recognizes the importance of shared interests.
When in Doubt...
Authors: Bendor Jonathan , Kramer Roderick M. , Stout Suzanne
Published: March 2007

In the last decade, there has been a resurgence of interest in problems of cooperation, stimulated largely by Axelrod's work. Using an innovative tournament approach, Axelrod found that a simple strategy, tit-for-tat (TFT), was most successful in playing the repeated prisoner's dilemma (PD) in a noiseless environment. However, recent analytical work has shown that monitoring problems caused by noise significantly impair TFT's effectiveness. The primary purpose of the present research is to discover whether there exist alternative strategies that perform well in noisy PDs. To investigate this question, the authors conducted a computer tournament. The results of the tournament demonstrated that, consistent with analytical work, TFT performed rather poorly. In contrast, strategies that were generous (i.e., cooperated more than their partners did) were quite effective.
Must We Fear a Post-Cold War Multipolar System?
Authors: Kegley Charles W. , Raymond Gregory A.
Published: March 2007

The probable transition from a bipolar to a multipolar international system has inspired divergent predictions about the likely consequences for global stability. This article places two recent exemplary deductive models under examination, in order to evaluate the validity of their conclusions about the alleged stability of the cold war's bipolar competitive world relative to that of multipolar systems. A review of the empirical evidence generated by inductive investigations of this relationship suggests that acceptance of the pessimistic thesis that multipolar systems are inherently unstable would be premature, and that, if intervening variables are considered, a rival, more pacific image of a future multipolar world is equally plausible.