bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting Individuals’ Interest After a Performance Result: The Roles of Motivational Orientations at High and Low Performance1
Authors: Hirschfeld Robert R. , Lawson Lucinda
Published: February 2008

This field study incorporated a trichotomous typology of motivations to explore interactions of a performance result with several motivational orientations in predicting subsequent interest in a learning endeavor. Although relevant literature suggests that low performance would be associated with lower interest, we hypothesized that motivation to approach mastery (i.e., learning and achievement orientations) would counteract this negative relationship. We also hypothesized that motivation to avoid poor performance (i.e., avoid–performance orientation) would exacerbate the link between low performance and lower interest. In light of theoretical issues concerning motivation to show competence (i.e., approach–performance orientation), we did not offer a hypothesis concerning this third type of motivation. Results supported only the hypothesized interactions. Implications of the findings are discussed.
Negative Perfectionism: Examining Negative Excessive Behavior in the Workplace
Authors: Leonard Nancy H. , Harvey Michael
Published: February 2008

The present paper explores the concept of negative perfectionism in the workplace. Negative perfectionism is unremitting and compulsive behavior in the process of striving to meet one's goals. We proposed that 4 types of negative or excessive behavior result from negative perfectionism in organizational settings: compulsive behavior, neurotic behavior, imposter behavior, and narcissistic behavior. Self‐concept‐based motivation theory was used as a framework for understanding how inaccuracies or inconsistencies between the evaluation of one's behavior in the workplace (goal‐setting behavior) and the type of feedback cues to which one decides to attend (feedback‐seeking behavior) might lead to these types of negative or excessive behaviors. Personal and managerial implications of negative perfectionism in organizational settings are discussed.

. . . when personal characteristics grate harmfully on others or significantly derail the success of the persons themselves, psychologists regard them not just as personality traits, but as personality disorders.

—Miller (1998)
Evaluations and Aggression Directed at a Gay Male Target: The Role of Threat and Antigay Prejudice1
Authors: Talley Amelia E. , Bettencourt B. Ann
Published: February 2008

This research was designed to understand heterosexual men's interpersonal reactions toward a gay male individual and to examine how threat and pre‐existing antigay prejudice impact these encounters. In one experiment, we manipulated the ostensible sexual orientation of an assigned work partner and assessed participants' perceptions of threat indirectly, using a measure of psychological distancing. Results revealed that, regardless of antigay prejudice, participants psychologically distanced more from the gay male than from the heterosexual male. In the second experiment, we manipulated threat and the sexual orientation of the work partner to examine aggressive responding toward the work partner. Participants exposed to a threat to their masculinity behaved more aggressively toward the gay work partner, regardless of their level of antigay prejudice.
Nationality Versus Humanity? Personality, Identity, and Norms in Relation to Attitudes Toward Asylum Seekers1
Authors: Nickerson Angela M. , Louis Winnifred R.
Published: February 2008

Right‐wing authoritarianism, social dominance orientation, Australian and human identity salience, and perceived Australian and human norms were related to the attitudes, feelings and behaviors toward asylum seekers of 242 Australian students and activists. Those high in right‐wing authoritarianism and social dominance orientation were less welcoming, as were participants who identified strongly as Australians and perceived hostile national norms. Independently, participants who identified strongly as humans were significantly more welcoming to asylum seekers, and an interaction was found such that those who identified strongly as Australians were more welcoming when they also identified strongly as humans. Implications for theories of identity and prejudice are examined, and interventions to reduce conflict by utilizing the human level of identification are discussed.
The Human Immunodeficiency Virus and the Cardiometabolic Syndrome in the Developing World: An African Perspective
Authors: Mutimura Eugene , Crowther Nigel J. , Stewart Aimee , Todd Cade W.
Published: February 2008

The advent of highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV)/AIDS into a manageable chronic disorder. Clinical care, however, needs to address the metabolic, anthropometric, and cardiovascular changes associated with HIV infection and HAART. Studies in developing countries suggest an increasing incidence of HIV‐associated cardiometabolic syndrome (CMS), especially in urban settings. Predictions indicate that the greatest increase in the prevalence of diabetes will occur in Africa over the next 2 decades due to lifestyle changes. This, coupled with increased access to HAART, may exponentially increase the prevalence of CMS in developing countries, where HIV infection is prevalent. Appropriate evaluation and intervention programs need to be implemented in the developing world, especially sub‐Saharan Africa, to curtail HIV‐related CMS. This should include routine cardiovascular risk assessments, management of HIV infection with more “metabolically friendly” HAART, and encouragment of lifestyle modifications, particularly smoking cessation, weight management, regular exercise, and adherence to a healthy diet.
Metabolic Syndrome Risks of Cardiovascular Disease: Differences Between HIV‐Positive and HIV‐Negative?
Authors: Reeds Dominic N.
Published: February 2008

Highly active antiretroviral therapy (HAART) has markedly prolonged life expectancy in patients infected with the human immunodeficiency virus (HIV). Use of HAART has been associated with development of a metabolic syndrome that may increase the risk of developing ischemic heart disease. The purpose of this review is to discuss the incidence and clinical manifestations of the metabolic syndrome in patients with HIV infection and contributing factors, as well as whether cardiovascular risk is disproportionately elevated in patients with HIV‐associated metabolic syndrome.
Accelerated Cardiovascular Disease and Myocardial Infarction Risk in Patients With the Human Immunodeficiency Virus
Authors: Sharma Tanvi S. , Messiah Sarah , Fisher Stacy , Miller Tracie L. , Lipshultz Steven E.
Published: February 2008

Highly active antiretroviral therapy has greatly reduced mortality among human immunodeficiency virus (HIV)‐infected patients by delaying, and possibly preventing, progression to AIDS. The risk of cardiovascular disease (CVD) is now an important consideration in these patients and may increase as they live longer. Risk factors for CVD, the inflammatory effects of HIV, and the metabolic complications of antiretroviral therapy may accelerate the onset of CVD. Death from myocardial infarction, however, is still rare compared with death from progression of HIV disease, and the benefits of antiretroviral therapy clearly outweigh any associated risk of CVD. In this review, the authors describe the risk of accelerated CVD in HIV‐infected individuals, the proposed viral and therapy‐related mechanisms of CVD, the clinical features of CVD in these patients, and monitoring and management guidelines to reduce CVD risk. Identifying, monitoring, and treating CVD risk factors in HIV‐positive patients is vital to improving their lives and should become standard practice.
Munc 18‐1 and Granuphilin Collaborate During Insulin Granule Exocytosis
Authors: Tomas Alejandra , Meda Paolo , Regazzi Romano , Pessin Jeffrey E. , Halban Philippe A.
Published: February 2008

Munc 18‐1 is a member of the Sec/Munc family of syntaxin‐binding proteins known to bind to the plasma membrane Q‐SNARE syntaxin1 and whose precise role in regulated exocytosis remains controversial. Here, we show that Munc 18‐1 plays a positive role in regulated insulin secretion from pancreatic beta cells. Munc 18‐1 depletion caused a loss in the secretory capacity of both transiently transfected INS 1E cells and a stable clone with tetracycline‐regulated Munc 18‐1 RNA interference. In addition, Munc 18‐1‐depleted cells exhibited defective docking of insulin granules to the plasma membrane and accumulated insulin in the trans Golgi network. Furthermore, glucose stimulation after Munc 18‐1 depletion resulted in the rapid formation of autophagosomes. In contrast, overexpression of Munc 18‐1 had no effect on insulin secretion. Although there was no detectable interaction between Munc 18‐1 and Munc‐18‐interacting protein 1 or calcium/calmodulin‐dependent serine protein kinase, Munc 18‐1 associated with the granular protein granuphilin. This association was regulated by glucose and was required for the specific interaction of insulin granules with syntaxin1. We conclude that Munc 18‐1 and granuphilin collaborate in the docking of insulin granules to the plasma membrane in an initial fusion‐incompetent state, with Munc 18‐1 subsequently playing a positive role in a later stage of insulin granule exocytosis.
β3‐Adrenoceptors modulate left ventricular relaxation in the rat heart via the NO‐cGMP‐PKG pathway
Authors: Angelone T. , Filice E. , Quintieri A. M. , Imbrogno S. , Recchia A. , Pulerà E. , Mannarino C. , Pellegrino D. , Cerra M. C.
Published: February 2008

Aims: Using a model of isolated and Langendorff‐perfused rat heart we analysed whether activation of β3‐adrenergic receptors (β3‐ARs) influences ventricular lusitropic performance. We also focused on the NOS/NO/cGMP/PKG cascade as the signal transduction mechanism.

Methods: Hearts were treated with increasing concentrations (from 10−12to 10−6 m) of BRL37344, a selective β3‐AR agonist, and cardiac performance was evaluated by analysing both lusitropic parameters and coronary motility. Cardiac preparations were also perfused with BRL37344in the presence of either isoproterenol (ISO) or nadolol, or pertussis toxin (PTx), or selective inhibitors of the NOS/NO/cGMP/PKG pathway.

Results: BRL37344caused a significant concentration‐dependent reduction in (LVdP/dt)min, a decrease in half time relaxation significant starting from 10−12 m, and an increase in (LVdP/dt)max/(LVdP/dt)minratio (T/−t). BRL37344abolished the ISO‐mediated positive lusitropism. β3‐AR‐dependent effects on relaxation were insensitive to β1/β2‐AR inhibition by nadolol (100 nm), and were abolished by Gi/oprotein inhibition by PTx (0.01 nm). NO scavenging by haemoglobin (10 μm), and nitric oxide synthase (NOS) inhibition by NG‐monomethyl‐l‐arginine (10 μm) revealed the involvement of NO signalling in BRL37344response. Pre‐treatment with inhibitors of either soluble guanylate cyclase (ODQ; 10 μm) or PKG (KT5823; 100 nm) abolished β3‐AR‐dependent negative lusitropism. In contrast, anantin (10 nm), an inhibitor of particulate guanylate cyclase, did not modify the effect of BRL37344on relaxation.

Conclusion: Taken together, our findings provide functional evidence for β3‐AR modulation of ventricular relaxation in the rat heart which involves PTx‐sensitive inhibitory Gi protein and occurs via an NO‐cGMP‐PKG cascade. Whether the effects of β3‐AR stimulation on lusitropism are beneficial or detrimental remains to be established.
What Makes Mental Associations Personal or Extra‐Personal? Conceptual Issues in the Methodological Debate about Implicit Attitude Measures
Authors: Gawronski Bertram , Peters Kurt R. , LeBel Etienne P.
Published: February 2008

Over the last decade, a new class of indirect measurement procedures has become increasingly popular in many areas of psychology. However, these implicit measures have also sparked controversies about the nature of the constructs they assess. One controversy has been stimulated by the question of whether some implicit measures (or implicit measures in general) assess extra‐personal rather than personal associations. We argue that, despite empirical and methodological advances stimulated by this debate, researchers have not sufficiently addressed the conceptual question of how to define extra‐personal in contrast to personal associations. Based on a review of possible definitions, we argue that some definitions render the controversy obsolete, whereas others imply fundamentally different empirical and methodological questions. As an alternative to defining personal and extra‐personal associations in an objective sense, we suggest an empirical approach that investigates the meta‐cognitive inferences that make a given association subjectively personal or extra‐personal for the individual.
Evolution and Personality: What Should a Comprehensive Theory Address and How?
Authors: Nichols Charles P. , Sheldon Kennon M. , Sheldon Melanie S.
Published: February 2008

Personality is arguably the most integrative area of psychology; yet, it is an area about which evolutionary psychologists have had comparatively little to say. This is unfortunate because evolutionary theory holds great potential as a framework that can link together the disparate aspects that make up a person. We suggest that progress in evolutionary personality psychology will be helped by clarification of precisely what an evolutionary theory of personality would need to address. To this end, we first describe and assess some extant contributions by theorists attempting to understand personality from an evolutionary perspective. Next, we endorse a working definition of what personality entails and outline three types of personality differences – character traits, goals/motives, and selves/identities – that any comprehensive evolutionary theory of personality should address. Finally, we suggest an approach forward, one where evolved species‐typical motives orient people toward adaptive ends and result in the differentiation of individuals’ unique selves.
Exportación de la atención médica administrada: experiencia asiática
Authors: Simonet Daniel
Published: February 2008

Extracto  Tras la saturación de la atención médica administrada en el mercado de los Estados Unidos y debido a las perspectivas limitadas en Europa, la atención médica administrada ha realizado algunos avances en América Latina y en el Sudeste asiático. El presente documento compara un concepto general, el de la «atención médica administrada», entre todos los países y muestra que ha venido ganando aceptación en algunos territorios (por ejemplo, en Filipinas y en Hong Kong), pero no en otros. Se define la atención médica administrada como los procesos o técnicas utilizados por cualquier entidad que ofrezca, administre y/o asuma el riesgo de los servicios de salud, a efectos de controlar o influir en la calidad, accesibilidad, utilización, costos y precios, o en los productos de esos servicios proporcionados a una determinada población (American Medical Association, 1999). La primera parte del documento revisa experiencias específicas (Indonesia, Filipinas, Malasia, Hong Kong, Singapur), y está seguida de un resumen de las dificultades encontradas por la atención médica administrada en Asia. Entre éstas, se encuentran la creciente oposición del público y la resistencia de los médicos.
Evaluación de las respuestas políticas de Singapur al envejecimiento, la desigualdad y la pobreza
Authors: Asher Mukul G. , Nandy Amarendu
Published: February 2008

Extracto  Singapur es un interesante caso de estudio en cuanto a la respuesta a un rápido envejecimiento, a las crecientes desigualdades y a una importante pobreza relativa. Por oposición a otros países asiáticos de altos ingresos, Singapur se basó en un régimen de ahorros obligatorio de un solo pilar para financiar la jubilación, la vivienda, y en menor medida, los cuidados de salud. Para responder a las bajas tasas de fertilidad, se ha permitido que la parte representada por la población extranjera se triplique entre 1990 y 2005, hasta alcanzar casi un 30 por ciento. Esto está alterando sutilmente la dinámica sociopolítica de Singapur, ayudando al mismo tiempo a mantener el crecimiento y la competitividad. En este documento sostenemos que Singapur tiene las capacidades fiscales, institucionales y de organización necesarias para tener un régimen de seguridad social moderno compuesto por múltiples pilares. Singapur está, sin embargo, determinado a continuar con el régimen actual, inadecuado e injusto, y que exige que los individuos y sus familias corran con parte exagerada del riesgo en la financiación de la jubilación, de los cuidados de salud y del mantenimiento del ingreso a corto plazo. Esto es el reflejo de decisiones políticas deliberadas producto de una visión Darwinista de la sociedad, así como de la necesidad de mantener un control sociopolítico.
La creación de la AISS y la OIT
Authors: Guinand Cédric
Published: February 2008

Extracto  La creación de la Asociación Internacional de la Seguridad Social (AISS) se ha visto sumamente influida por la Organización Internacional del Trabajo (OIT), que era, sin duda alguna, la estrella ascendente en el mundo de las organizaciones internacionales en el período comprendido entre las dos guerras mundiales. Sin embargo, no sería del todo correcto pensar que, a la hora de la creación de la AISS, la OIT hubiese sido la única institución que había podido imponer sus criterios. En efecto, estos dos organismos tenían antecesores, como la PPIAS y la AIPLT, al igual que otros actores de la época, como la Asociación Internacional Profesional de Médicos, y la internacionalización del movimiento de los seguros sociales, que contribuyeron a la fundación de esa nueva asociación, que atravesó, no obstante, algunos momentos difíciles a lo largo de esos primeros años.
Current concepts in chemotherapy for malignant pleural mesothelioma
Authors: Sørensen Jens Benn
Published: February 2008

Objectives:  The aim of this study was to provide an overview of the most active single agents and combination regimens in malignant pleural mesothelioma (MPM).

Data Source:  Literature on English‐language trials in humans was searched on Medline until October 2007. Indexing terms were malignant pleural mesothelioma and chemotherapy.

Study Selections:  Trials with ≥15 patients and with data on activity were included.

Results:  Detorubicin and pirarubicin have response rates (RRs) of 22%–26%, epirubicin of 5%–15%, docetaxel of 5%–23% and vinorelbine of 24%. Other active agents were ifosfamide (3%–24%) and mitomycin C (21%). Carboplatin and cisplatin have an overall RR of 11% in three studies and 17% in four studies, respectively. Antimetabolites were active, including methotrexate (37%), raltitrexed (21%), edatrexate (16%–25%) and pemetrexed (15%). With respect to combination chemotherapy regimens, only cisplatin with either pemetrexed or raltitrexed has been compared with other substances, in both cases to cisplatin monotherapy. Both showed a survival advantage, which was statistically significant in the trial including pemetrexed, suggesting that chemotherapy improved survival in MPM. No studies have compared chemotherapy with the best supportive care alone, and none has compared different combination chemotherapy regimens with each other.

Conclusions:  A number of single‐agent cytotoxics posess moderate activity against MPM. A number of platinum‐based combination chemotherapy regimens show similar activities, but none has been compared with another combination. Cisplatin with either raltitrexed or pemetrexed has improved survival compared with cisplatin alone, and may be used as a reference treatment in randomized trials. Targeted agents should be explored in order to further improve the outcome.

Please cite this paper as: Sørensen JB. Current concepts in chemotherapy for malignant pleural mesothelioma. The Clinical Respiratory Journal 2008; 2: 74–79.
Hochschild cohomology via incidence algebras
Authors: Redondo María Julia
Published: February 2008

Given an algebra A, we associate an incidence algebra A(Σ) and compare their Hochschild cohomology groups.
On multiply connected wandering domains of meromorphic functions
Authors: Rippon P. J. , Stallard G. M.
Published: February 2008

We describe conditions under which a multiply connected wandering domain of a transcendental meromorphic function with a finite number of poles must be a Baker wandering domain, and we discuss the possible eventual connectivity of Fatou components of transcendental meromorphic functions. We also show that if f is meromorphic, U is a bounded component of F(f) and V is the component of F(f) such that f(U)⊂V, then f maps each component of ∂ U onto a component of the boundary of V in ℂ̂. We give examples which show that our results are sharp; for example, we prove that a multiply connected wandering domain can map to a simply connected wandering domain, and vice versa.
A Coupled-Mode, Phase-Resolving Model for the Transformation of Wave Spectrum Over Steep 3D Topography: Parallel-Architecture Implementation
Authors: Gerostathis Th. P. , Belibassakis K. A. , Athanassoulis G. A.
Published: February 2008

The problem of transformation of the directional spectrum of an incident wave system over an intermediate-depth region of strongly varying 3D bottom topography is studied in the context of linear theory. The consistent coupled-mode model, developed by Athanassoulis and Belibassakis (J. Fluid Mech. 389, pp. 275–301 (1999)) and extended to three dimensions by Belibassakis et al. (Appl. Ocean Res. 23(6), pp. 319–336 (2001)) is exploited for the calculation of the linear transfer function, connecting the incident wave with the wave conditions at each point in the field. This model is fully dispersive and takes into account reflection, refraction, and diffraction phenomena, without any simplification apart the standard intermediate-depth linearization. The present approach permits the calculation of spectra of all interesting wave quantities (e.g., surface elevation, velocity, pressure) at every point in the liquid domain. The application of the present model to realistic geographical areas requires a vast amount of calculations, calling for the exploitation of advanced computational technologies. In this work, a parallel implementation of the model is developed, using the message passing programming paradigm on a commodity computer cluster. In that way, a direct numerical solution is made feasible for an area of 25km2 over Scripps and La Jolla submarine canyons in Southern California, where a large amount of wave measurements are available. A comparison of numerical results obtained by the present model with field measurements of free-surface frequency spectra transformation is presented, showing excellent agreement. The present approach can be extended to treat weakly nonlinear waves, and it can be further elaborated for studying wave propagation over random bottom topography.
Solution of the Boundary Layer Problems for Calculating the Natural Modes of Riser-Type Slender Structures
Authors: Chatjigeorgiou Ioannis K.
Published: February 2008

The present work treats the bending vibration problem for vertical slender structures assuming clamped connections at the ends. The final goal is the solution of the associated eigenvalue problem for calculating the natural frequencies and the corresponding mode shapes. The mathematical formulation accounts for all physical properties that influence the bending vibration of the structure including the variation in tension. The resulting model incorporates all principal characteristics, such as the bending stiffness, the submerged weight, and the function of the static tension. The governing equation is treated using a perturbation approach. The application of this method results in the development of two boundary layer problems at the ends of the structure. These problems are treated properly using a boundary layer problem solution methodology in order to obtain asymptotic approximations to the shape of the vibrating riser-type structure. Here, the term “boundary layer” is used to indicate the narrow region across which the dependent variable undergoes very rapid changes. The boundary layers adjacent to the clamped ends are associated with the fact that the stiffness (which is small) is the constant factor multiplied by the highest derivative in the governing differential equation.
Stability and Vibration of a Rotating Circular Plate Subjected to Stationary In-Plane Edge Loads
Authors: Shen I. Y. , Song Y.
Published: February 2008

This paper predicts transverse vibration and stability of a rotating circular plate subjected to stationary, in-plane, concentrated edge loads. First of all, the equation of motion is discretized in a plate-based coordinate system resulting in a set of coupled Hill’s equations. Through use of the method of multiple scales, stability of the rotating plate is predicted in closed form in terms of the rotational speed and the in-plane edge loads. The asymmetric membrane stresses resulting from the stationary in-plane edge loads will transversely excite the rotating plates to single-mode parametric resonances as well as combination resonances at supercritical speed. In addition, introduction of plate damping will suppress the parametric instability when normalized edge loads are small. Moreover, the radial in-plane edge load dominates the rotational speed at which the instability occurs, and the tangential in-plane edge load dominates the width of the instability zones.
Asymptotic Theory of Broadband Rotor Thrust, Part I: Manipulations of Flow Probabilities for a High Number of Blades
Authors: Martinez R.
Published: February 2008

Modern computer predictions of the frequency spectrum of net thrust for a rotor in turbulent flow display a number of features that call for interpretation. The success of the asymptotic development described here in providing the needed explanations lies in the relative generality of the model. The rotor is fully three dimensional. It is not a cutaway blade row. The theory’s only requirement is that the number of blades be large (six is enough). The most practical aspect of the new work is that it supplies a highly accurate analytical solution for the broadband “haystacking” in a propulsor of high solidity. An important intermediate result is that the probabilistic amplitude of random gusts perceived by that propulsor climbs radially outwards along its blades, solely by virtue of the three-dimensional kinematics of the rotor’s aerodynamic sampling of the turbulent flowfield: The behavior is r3 for the normal-to-rotor flow statistics and r4 for the cross correlation of normal and in-plane downwash components. The final effect is a spanwise distribution of sectional loads that is highly concentrated at the blade tips. The turbulence in the present study is homogeneous and isotropic but its integral scale may take on essentially any value and the asymptotic analysis still holds.
Steady Motions of a Drawn Cable
Authors: O’Reilly O. M.
Published: February 2008

The steady motions of nonlinearly elastic and inextensible strings which are being drawn between two fixed points and are subject to a gravitational load are examined. It is shown that, dependent on the boundary conditions, constitutive equations and a reference drawing speed, multiple co-existant steady motions are possible in certain situations. Using a variational method, stability criteria are also established for some of these motions.
Principles of Localized Buckling for a Strut on an Elastoplastic Foundation
Authors: Hunt G. W. , Blackmore A.
Published: February 2008

Localization theory for long continuous structures is extended to the buckling of a thin elastic strut supported by a bilinear elastoplastic medium. It is demonstrated that the form of localization has much in common with the buckling of struts on linear and nonlinear elastic foundations in that the localized response, which is of the greatest practical significance, is accompanied by a myriad of associated less significant solutions including periodic ones. Special shooting techniques are developed to deal with the problem of finding the localized solutions from amongst all competing possibilities.
Thermal Stresses due to a Laser Pulse: Elastic Solution
Authors: Hector L. G. , Hetnarski R. B.
Published: February 2008

The thermal stress field in an elastic half-space due to a single pulse from a laser is derived for the general case of a mixed-mode structure beam. The mode structure models the output from a cylindrical laser resonator and thus defines a radially symmetric intensity distribution about the beam axis. The functional form of the temporal pulse profile is quite general in that it models the temporal pulse shapes emitted by a laser that is either internally pulsed through radio frequency modulation of its power supply, Q-switched, or mode locked. It also models a continuous beam that is mechanically chopped through external means.
Punch Problems for an Anisotropic Elastic Half-Plane
Authors: Fan C. W. , Hwu Chyanbin
Published: February 2008

By combining Stroh’s formalism and the method of analytical continuation, several mixed-typed boundary value problems of an anisotropic elastic half-plane are studied in this paper. First, we consider a set of rigid punches of arbitrary profiles indenting into the surface of an anisotropic elastic half-plane with no slip occurring. Illustrations are presented for the normal and rotary indentation by a flat-ended punch. A sliding punch with or without friction is then considered under the complete or incomplete indentation condition.
The Folding of Triangulated Cylinders, Part III: Experiments
Authors: Guest S. D. , Pellegrino S.
Published: February 2008

This paper describes an experimental investigation of a type of foldable cylindrical structure, first presented in two earlier papers. Three cylinders of this type were designed and manufactured, and were then tested to find the force required to fold them. The results from these tests show some discrepancies with an earlier computational simulation, which was based on a pin-jointed truss model of the cylinders. Possible explanations for these discrepancies are explored, and are then verified by new simulations using computational models that include the effect of hinge stiffness, and the effect of geometric imperfections.
The Freestream Matching Condition for Stagnation Point Turbulent Flows: An Alternative Formulation
Authors: Abid R. , Speziale C. G.
Published: February 2008

The problem of plane stagnation point flow with freestream turbulence is examined from a basic theoretical standpoint. It is argued that the singularity which arises in the standard K–ε model results from the use of an inconsistent freestream boundary condition. The inconsistency lies in the implementation of a production-equals-dissipation equilibrium hypothesis in conjunction with a freestream mean velocity field that corresponds to homogeneous plane strain—a turbulent flow for which the standard K–ε model does not predict such a simple equilibrium. The ad hoc adjustment that has been made in the constants of the ε-transport equation to eliminate this singularity is shown to be inconsistent for homogeneous plane-strain turbulence as well as other benchmark turbulent flows. An alternative means to eliminate this singularity—without compromising model predictions in more basic turbulent flows—is proposed based on the incorporation of nonequilibrium vortex stretching effects in the turbulent dissipation rate equation.
Theory for Multilayered Anisotropic Plates With Weakened Interfaces
Authors: Cheng Zhen-qiang , Jemah A. K. , Williams F. W.
Published: February 2008

Rigorous kinematical analysis offers a general representation of displacement variation through thickness of multilayered plates, which allows discontinuous distribution of displacements across each interface of adjacent layers so as to provide the possibility of incorporating effects of interfacial imperfection. A spring-layer model, which has recently been used efficiently in the field of micromechanics of composites, is introduced to model imperfectly bonded interfaces of multilayered plates. A linear theory underlying dynamic response of multilayered anisotropic plates with nonuniformly weakened bonding is presented from Hamilton’s principle. This theory has the same advantages as conventional higher-order theories over classical and first-order theories. Moreover, the conditions of imposing traction continuity and displacement jump across each interface are used in modeling interphase properties. In the special case of vanishing interface parameters, this theory reduces to the recently well-developed zigzag theory. As an example, a closed-form solution is presented and some numerical results are plotted to illustrate effects of the interfacial weakness.
Out-of-Plane Displacement Derivative Measurements Using Interferometric Strain/Slope Gage
Authors: Li Keyu
Published: February 2008

An optical method originally developed for measuring derivatives of in-plane displacements is redefined to measure derivatives of out-of-plane displacements. The technique is based on interference of laser beams reflected and diffracted from two microindentations closely depressed on a specimen surface. As in-plane and out-of-plane displacements cause the microindentations to move relatively to each other, the two interference fringe patterns change accordingly. Movement of the interference fringes is monitored with linear photodiode arrays and analyzed via a computer-controlled system that allows simultaneous measurements of the in-plane and out-of-plane displacement derivatives. The technique is referred to as the interferometric strain/slope gage (ISSG). Having short gage length (˜100 μm), the technique is unique for measurements of high deformation gradients and for applications in complex geometries. Its principle as well as an experimental validation of measuring bending strains/stresses and deflection slopes in a cantilever beam is presented. The experiment shows that both the first-order and second-order derivatives of out-of-plane displacements can be obtained. Measurement sensitivities to in-plane and out-of-plane rigid-body motions are systematically investigated. The technique can be potentially extended to measure large deflection angles. The derived governing equations indicate a coupling effect between the in-plane and out-of-plane components. The associated instrumentation for data acquisition and analysis is described in great detail.
On the Oblique Compression of Two Elastic Spheres
Authors: Elata D.
Published: February 2008

In this note Walton’s (1987) force-displacement relations for a contact between two identical elastic spheres are discussed. The relations are based on the solution for the oblique compression of two elastic spheres (Walton, 1978) which is rederived here in a simple fashion that relates it to Mindlin’s (1949) solution for contact stress. Specific limitations of these relations are reviewed and it is demonstrated that misusing the relations leads to thermodynamic inconsistencies.
An Integral-Equation Formulation for Anisotropic Elastostatics
Authors: Perez M. M. , Wrobel L. C.
Published: February 2008

In this paper a conceptually simple integral-equation formulation for homogeneous anisotropic linear elastostatics is presented. The basic idea of the approach proposed here is to rewrite the system of differential equations of the anisotropic problem to enable the use of the isotropic fundamental solution. This procedure leads to an extended form of Somigliana’s identity where a domain term occurs as a result of the anisotropy of the material. A supplementary integral equation is then established to cope with the resulting domain unknowns. Although the solution of these integral equations requires discretization of the contour of the structural component into boundary elements and its domain into internal cells, the numerical scheme presented here depends only on the boundary variables of the problem. Once the boundary solution is obtained it is possible to compute the unknowns within the domain, if required. The main objective of the present work is to develop an alternative integral-equation formulation that could be used to reduce the time needed to compute three-dimensional solutions for linear homogeneous anisotropic problems. Another possible advantage of the proposed formulation is its generality, which enables its direct extension to include dynamic and plastic effects in the analysis. Encouraging results are presented for four examples where structural elements are submitted to tension and shear effects.
A Generalized Method of Rotational Superposition for Problems With Elliptical Distribution of Boundary Values
Authors: Lai Gwolong , Robinson A. R.
Published: February 2008

An extension of the usual rotational superposition is developed from geometrical considerations. This approach relates the solution of any dynamic or static elasticity problem which corresponds to boundary values on a circular area to the solution of the problem in which the same boundary values are “stretched” in one direction. From the two-dimensional problems that correspond by rotational superposition to the circular case, new two-dimensional problems are formulated which, when super-posed properly, result in the solution for the elliptical boundary distribution. This new technique is first presented for stretching the boundary values of axially symmetric problems, and then extended to others, including the elliptical shear dislocation problem.
Subsonic and Intersonic Crack Growth Along a Bimaterial Interface
Authors: Singh R. P. , Shukla A.
Published: February 2008

An experimental investigation has been conducted to study the dynamic failure of bimaterial interfaces. Interfacial crack growth is observed using dynamic photoelasticity and characterized in terms of crack-tip velocity, complex stress intensity factor, and energy release rate. On the basis of crack-tip velocity two growth regimes are established, viz. the subsonic and transonic regimes. In the latter regime crack-tip velocities up to 1.3 times the shear wave velocity of the more compliant material are observed. This results in the formation of a line of discontinuity in the stress field surrounding the crack tip and also the presence of a pseudo crack tip that travels with the Rayleigh wave velocity (of the more compliant material).
The Elastic Field in a Half-Space With a Circular Cylindrical Inclusion
Authors: Wu L. Z. , Du S. Y.
Published: February 2008

The problem of a circular cylindrical inclusion with uniform eigenstrain in an elastic half-space is studied by using the Green’s function technique. Explicit solutions are obtained for the displacement and stress fields. It is shown that the present elastic fields can be expressed as functions of the complete elliptic integrals of the first, second, and third kind. Finally, numerical results are shown for the displacement and stress fields.
Effect of Orthotropy on the Intersonic Shear Crack Propagation
Authors: Piva A. , Hasan W.
Published: February 2008

Of concern in the present paper is the steady-state elastodynamic problem of a semi-infinite shear crack, propagating in an orthotropic medium. An intersonic regime is assumed which leads to a significant change of the singularity at the crack tip.
On the Analysis and Design of Fiber-Reinforced Composite Shells
Authors: Kalamkarov A. L. , Kolpakov A. G.
Published: February 2008

Closed-form solutions based on a general homogenization composite shell model are obtained for the effective stiffness moduli of the high-stiffness fiber-reinforced angle-ply composite shell. The design problem for the fiber-reinforced shell having the required set of effective stiffnesses is formulated and solved. The set of prescribed stiffnesses for which the design problem is solvable is described, and the effective method of the design parameters calculation based on convex analysis is developed. The minimum number of reinforcing layers required for the design of the fiber-reinforced angleply shell with the prescribed stiffnesses is determined. The solution of design problem is generalized on account of minimization of the fiber volume content.
Three-Dimensional Finite Element Analysis of Subsurface Stresses and Shakedown Due to Repeated Sliding on a Layered Medium
Authors: Kral E. R. , Komvopoulos K.
Published: February 2008

Results of three-dimensional finite element simulations are presented for the subsurface stress and strain fields in a layered elastic-plastic half-space subjected to repeated sliding contact by a rigid sphere. A single perfectly adhering layer with an elastic modulus and yield strength both two and four times that of the substrate material is modeled. Applied sliding loads are equivalent to 100 and 200 times the initial yield load of the substrate material and sliding is performed to distances of approximately two times the contact radius. The effects of layer material properties and normal load on the loaded and residual stresses occurring from repeated load cycles are examined and compared with stresses produced during the first load cycle. Results for the maximum tensile stresses at the layer/substrate interface and the maximum principal stress in the substrate are presented and their significance for layer decohesion and crack initiation is discussed. Further yielding of substrate material during unloading is discussed, and the possibility of shakedown to an elastic or plastic loading cycle is analyzed for the different material properties and contact loads investigated.
Velocity and Acceleration Analysis of Contact Between Three-Dimensional Rigid Bodies
Authors: Sankar N. , Kumar V. , Yun Xiaoping
Published: February 2008

During manipulation and locomotion tasks encountered in robotics, it is often necessary to control the relative motion between two contacting rigid bodies. In this paper we obtain the equations relating the motion of the contact points on the pair of contacting bodies to the rigid-body motions of the two bodies. The equations are developed up to the second order. The velocity and acceleration constraints for contact, for rolling, and for pure rolling are derived. These equations depend on the local surface properties of each contacting body. Several examples are presented to illustrate the nature of the equations.
Anisotropic Damage Effect Tensors for the Symmetrization of the Effective Stress Tensor
Authors: Voyiadjis G. Z. , Park T.
Published: February 2008

Based on the concept of the effective stress and on the description of anisotropic damage deformation within the framework of continuum damage mechanics, a fourth order damage effective tensor is properly defined. For a general state of deformation and damage, it is seen that the effective stress tensor is usually asymmetric. Its symmetrization is necessary for a continuum theory to be valid in the classical sense. In order to transform the current stress tensor to a symmetric effective stress tensor, a fourth order damage effect tensor should be defined such that it follows the rules of tensor algebra and maintains a physical description of damage. Moreover, an explicit expression of the damage effect tensor is of particular importance in order to obtain the constitutive relation in the damaged material. The damage effect tensor in this work is explicitly characterized in terms of a kinematic measure of damage through a second-order damage tensor. In this work, tensorial forms are used for the derivation of such a linear transformation tensor which is then converted to a matrix form.
Damping Characteristics of Laminated Thick Plates
Authors: Taylor T. W. , Nayfeh A. H.
Published: February 2008

We develop the analysis for the exact three-dimensional viscoelastic solution for simply supported, thick multilayered composite plate strips. Each layer is assumed to possess monoclinic or higher material symmetry and to be perfectly bonded to adjacent layers. The damping capacity, or loss factor, of the composite plate is derived using energy principles, allowing analysis of arbitrary through-the-thickness geometry for the composite plate. The damping characteristics of the composite plate, as well as its natural modes of vibration, are obtained with the aid of the matrix transfer technique. The matrix transfer method simplifies the requisite analytical developments as well as speeding the numerical calculations. While our analysis treats general material anisotropy and arbitrary through-the-thickness geometry, we examine, as special cases of our analysis, constrained layer damping treatments and sandwich plates. We compare our solution with previous well-known solutions that rely on complex bending modulus formulations and isotropic materials in simple layered treatments. The modal damping capacity of the composite plate is investigated as a function of both frequency of vibration and as a function of material damping modulus.
Parametric Resonance of a Spinning Disk Under Space-Fixed Pulsating Edge Loads
Authors: Chen Jen-San
Published: February 2008

The parametric resonance of a spinning disk under a space-fixed pulsating edge load is investigated analytically. We assume that the radial edge load can be expanded in a Fourier series. With use of the orthogonality properties among the eigenfunctions of a gyroscopic system, the partial differential equation of motion is discretized into a system of generalized Hill’s equations in the first-order form. The method of multiple scale is employed to determine the conditions for single mode as well as combination resonances to occur. For any two modes, with s and υ nodal diameters, respectively, combination resonance occurs only when there exists a specific Fourier component cos kθ in the edge load, where s + υ = ±k. Sum type resonance occurs when both modes are reflected or both modes are nonreflected. On the other hand, difference type resonance occurs when one mode is reflected and the other is nonreflected. In applying this rule, the number of nodal diameters of a forward and a reflected wave is considered as negative. Several typical loadings are discussed, including uniform and concentrated edge loads.
Stability of the Unison Response for a Rotating System With Multiple Tautochronic Pendulum Vibration Absorbers
Authors: Chao Chang-Po , Shaw S. W. , Lee Cheng-Tang
Published: February 2008

Due to spatial and balancing considerations, the implementation of centrifugal pendulum absorbers (CPVA’s) invariably requires that the total absorber inertia be divided into several absorber masses and stationed about the center of rotation. To achieve the designed-for performance, the CPVA’s are expected to move in exact unison, since the selection of the total absorber mass is made by assuming an equivalent single absorber mass. In this paper, we determine the conditions under which the unison motion of a system of several identical CPVA’s is dynamically stable. This is done for the special case of tautochronic absorbers subjected to a purely harmonic torque. The stability criterion is obtained by an asymptotic method that exploits certain symmetries in the equations of motion and is based on the assumption that total moment of inertia of the absorbers is much smaller than that of the entire rotating system—an assumption that is almost always satisfied in practice. It is expressed in terms of a critical torque level that is proportional to the square root of the equivalent viscous damping of the individual absorbers. The result is verified by numerical simulations of the system near the critical parameter conditions. A future paper will consider the post-critical response of the system.