Scaling of stacking fault energy and deformation temperature on strain hardening of FCC metals and alloys

The strain-hardening behaviour of metals and alloys are significantly affected by the dynamic recovery process, the rate of which can be increased by increases in deformation temperature and/or stacking fault energy (SFE). In the present work, the decay slope of the strain-hardening rate with flow stress as a function of both temperature and stacking fault energy is quantitatively evaluated for several face-centered cubic metals and alloys. A universal and quantitative approach to the scaling of the effects of temperature and stacking fault energy on strain-hardening behaviour is developed, which could be useful for predicting deformation behaviour or for material design.     

Stress reduction experiments during constant-strain-rate tests in Cu and Ge

The technique of rapid reductions in applied stress (dip test) is occasionally performed in creep testing. In the work reported here, the technique was applied during a constant-strain-rate test. Both variants, the stress dip test and the strain dip test, give equivalent results. The specimen strain has to be measured in both cases; however, the strain dip technique is preferred since anelastic effects do not interfere. It is shown that the response of Cu and Ge single crystals to fast stress reductions, on the level of the internal stress and below it, is strongly material dependent, reflecting differences in microstructural processes involved in the plastic deformation. These processes are discussed.     

Finite-element method for the determination of the surface stress field from the real microstructure of anisotropic materials

A method is described for determining the surface stress distribution from the real microstructure of materials. The major advantages of the analyses, including the determination of anisotropic mechanical and crystallographic properties, are identified. The calculation involves the development of image analysis processing and the implementation in the finite-element code Cast3M of a new procedure for meshing the real microstructure and material models capable of describing the complex behaviour of real materials. The method is applied to the case of austenoferritic stainless steels.     

Stable singular or negative stiffness systems in the presence of energy flux

We report stable systems which exhibit quasistatic stiffness that can be negative or tend to infinity without external constraint. They are based on coupled fields in the non-equilibrium presence of energy flux that is modulated by force. They evade thermodynamic restrictions by relaxing a restrictive assumption: equilibrium. Negative values of physical properties, including compressibility and heat capacity, are considered forbidden in classical thermodynamics; such analyses provide bounds on the stiffness and other properties of multiphase materials. Stable negative and singular stiffness is demonstrated experimentally in a piezoelectric system and in a thermoelastic granular material. Coupled fields occur naturally under a wide range of conditions and form the basis for many forms of technology including sensors, actuators, and electric coolers. Because all materials exhibit at least one coupled field effect, the concept is broadly general and is applicable to attaining extreme values of any physical property e.g. stiffness, permittivity, piezoelectricity.     

Relationship between perceived job stress and physical and psychological strain among university administrators

The relations between eight job stresses and symptoms of physical and psychological strain were examined among 56 university administrators. Only three of the 16 stressor-strain correlations were significant, suggesting that stress is weakly related to individual strain in this sample.     

On convergence of the generalized Maxwell scheme: conductivity of composites containing cubic arrays of spherical particles

The Maxwell concept of equivalent inhomogeneity generalized to account for the interactions between the particles in the cluster and combined with recently reported results on the polarizability of a cube is used to evaluate the effective conductivities of the materials reinforced by cubic arrays of spherical particles. New numerical results demonstrate that the estimates of the effective properties based on the generalized Maxwell scheme with the equivalent inhomogeneity of cubic shape converge to the accurate periodic benchmark solutions, unlike spherical shape-based estimates.     

The use of stories as autistic objects

This paper reviews Frances Tustin's concept of the 'autistic object' and its development over the course of her writings. Clinical material from work with a 4-year-old boy is brought to suggest that the concept can usefully be extended to include such cultural artefacts as stories as well as the physical objects emphasized by Tustin. It is also emphasized that the awareness of reality which autistic objects are used to defend against refers both to internal as well as external reality. The paper argues that it is the function to which the object is put that is critical in determining whether or not it should be viewed as an autistic object.     

A relationship among the components of the Eshelby tensor and its physical meaning in general inclusion problems

For an ellipsoidal inclusion with uniform eigenstrains in an infinitely extended material, the total strains in the inclusion are given by the well known Eshelby tensor S_ijkl. A general relationship S₁₁₁₁+S₂₂₂₂+S₃₃₃₃+2(S₁₂₁₂+S ₂₃₂₃+S₃₁₃₁) = 3 among the components of the Eshelby tensor and its physical meaning are reported. It is shown that the relationship can be extended to an inclusion with any shape in a material with any anisotropic elastic moduli.     

Fear of contamination

Compulsive cleaning is an attempt to remove feelings of contamination that threaten one's physical health, mental health or ability to function socially. The fear of becoming contaminated can be complex, powerful, persistent and easily spread. Contamination is defined, the main types of contaminants set out and the characteristics of the fear are described. The distinction between normal and abnormal feelings of contamination is considered, and abnormal beliefs about contamination are analysed. Attention is drawn to the fact that contamination can occur without any physical contact, and the concept of mental pollution is used to elucidate this process. The causes and consequences of contamination fears are described, and some connections between fear and disgust are considered. The concept of cognitive co-morbidity is applied to an analysis of associations between the fear of contamination and obsessions, social fears and phobias. It is suggested that applying cognitive analyses and tactics may improve our ability to treat these powerful and tenacious fears.     

Dynamic deformation of shape-memory alloys: Evidence of domino detwinning?

Deformation of NiTi shape-memory alloys (SMAs) under dynamic tension has been studied. It is found that the stress plateau associated with detwinning still exists at the highest strain rate tested (300s -1 ). Beyond the stress plateau, when dislocation mechanisms dominate the deformation process, the strain-hardening effect is more strongly dependent on strain rate. The dynamically deformed specimens exhibit a shape-recovery process and a two-way memory effect which are identical with that for the alloy deformed under quasistatic conditions. The observations suggest that the detwinning process takes place in SMAs under dynamic tension.     

Topological interlocking of protective tiles for the space shuttle

We propose a new concept of design of heat- and impact-resistant tile covering for space shuttles based upon topological interlocking of tiles. The key features of this type of tiling are as follows: firstly, the tiles are kept in place by virtue of the geometry of their contacting surfaces alone, so that no binding agent needs to be used; secondly, failure of an individual element does not compromise the structural integrity of the tile assembly and, moreover, a failed tile will be kept in place by its neighbours, thus maintaining its thermal protection function; thirdly, topological interlocking removes the need for connectors or other stress concentrators deleterious in extreme conditions of space flight and re-entry. Topological interlocking is scale and material independent, which permits combining tiles made from different materials in any proportion.     

Informed consent—Wishful thinking?

This article is concerned with the concept of “informed consent” as applied both in biomedical research involving human subjects and in clinical medicine in general. The current crisis over the elaboration and interpretation of the concept will be examined, along with the broader question of whether “informed consent” is any longer meaningful or viable as a criterion for complex bioethical policy-making. Finally, I will attempt to sketch a prognosis for the concept in doctor-patient relations, even if it is only wishful thinking.     

The relation of job control with job strains: A comparison of multiple data sources

This study represents a secondary analysis of existing data that were used in Spector and Jex's (1991) paper. The self‐report and rater‐report job‐stress data were identical to those used in the study by Spector and Jex (1991) . To gain a greater insight into the connections between the objective work environment and employees' job strains, this study added the job‐stress data from a newly developed objective data source – the Occupational Information Network (O*NET) database. We found that an O*NET stressor was related to physical and behavioural strains. There is something in the objective environment that plays a role in employees' physical well‐being and behaviour. Objectively measured stressors, however, were unrelated to psychological strains. Explanations were given to the lack of the relationship. Based on these findings, we suspect that there may be somewhat different factors at work for each type of strain.     

学校正念干预的应用与特点

“学校正念干预”(School-Based Mindfulness Intervention)是将正念理论及技术应用到教育领域而形成的非医疗健康干预新策略。一方面,学校正念干预能有效帮助学生改善身心行为问题,提高认知能力;另一方面,它能够增强教师压力管理能力和幸福感。总的来说,学校正念干预是以“大健康”为目标、以“非评判接纳”为视角、以校园为干预情境、以传统学校项目为基础的校园非医疗健康干预,是学校心理健康工作者、学校专业社工可采取的策略。未来研究应注重其成效评估和测量、理论机制及应用问题的研究。     

Increasing the probability of finding an interaction in work stress research: A two‐wave longitudinal test of the triple‐match principle

Research into work stress has attempted to identify job resources that can moderate the effects of job demands on strain. The recently developed triple‐match principle (TMP) proposes that job demands, resources, and strain can be conceptualized as being composed of cognitive, emotional, and physical dimensions. When a psychological imbalance is induced by job demands, individuals activate corresponding resources to reduce the effects of the demands. A closer match occurs when the resources are processed in the same psychological domain as the demands. The further away from a match, the less likely an interactive effect will become. Put simply, the likelihood of finding an interactive effect between job demands and job resources is greatest when demands, resources, and strain are based on qualitatively similar dimensions (i.e. cognitive, emotional, and physical). For example, emotional support from colleagues is likely to buffer the effects of emotional demands on emotional exhaustion. The TMP was tested in a sample of 179 Australian police officers in a two‐wave longitudinal study. The likelihood of finding an interactive effect was related to the degree of match between job demands, job resources, and strain with 33.3% of triple‐match interactions significant, 22.2% when there was a double‐match, and 0.0% when there was no match. These findings lend support to the TMP as a guiding framework, for research, to explore possible interactive effects in work stress research, and for practice, to inform interventions matching resources to occupational demands, to offset strain.     

论现象概念——解析当前物理主义与反物理主义争论的一个焦点

现象概念是当前心灵哲学里物理主义和反物理主义争论的一个焦点,但尚未引起国内学界的重视。本文打算首先分析现象概念引起关注的主要原因。其次,参考最新的研究文献,考察现象概念的三个基本特性(孤立性、指称物在场、首尾相接),概述物理主义和反物理主义围绕现象概念而进行的主要争论。并在此基础之上,归结出一条约束现象概念与其指称之间关系的硬信念原则(hard belief principle,HBP)。最后,简略探讨了围绕现象概念的争论对于我们理解物理概念及其相关问题可能带来的一些影响。     

Nanoindentation response of anisotropic piezoelectric materials

A three-dimensional finite element model is developed to accurately capture the force–depth and charge–depth nanoindentation response of several classes of anisotropic piezoelectric materials such as relaxor ferroelectrics for which analytical models are at present unavailable. Upon validating the finite element model for transversely isotropic materials, it is demonstrated that the nanoindentation response of anisotropic piezoelectric materials displays a strong dependence on the nature of the indenter geometry and relatively weak dependence on the indenter conductivity. Furthermore, by recourse to “longitudinal” and “transverse” indentations, the nanoindentation method can also be used to identify the poling directions in piezoelectric materials as well.     

Nominally and rigorously parallel test forms

When several test forms are used interchangeably, they will not in practice, despite all efforts, be rigorously parallel. A definition of the standard error of measurement appropriate for this type of situation can be provided; however, it will be different from the definition in classical test theory. Appropriate formulas for the standard error of measurement and for other related quantities under both definitions are derived and compared; also sample statistics for estimating these quantities.The writer is indebted to Lee Cronbach and Julian Stanley for many helpful suggestions for revising a draft of this paper. Part of the work was carried out while the writer was Brittingham Visiting Professor at the University of Wisconsin. This work was supported in part by contract Nonr-2752(00) between the Office of Naval Research and Educational Testing Service. Reproduction in whole or in part for any purpose of the United States Government is permitted. The termnominally parallel was suggested by Lee Cronbach.     

To be me or not to be me: About alienation

This article is about the experiential side of the concept of alienation and its relations to the stress process in the context of work and organization. We distinguish two kinds of alienation: primary alienation, the experience or feeling that something is different from normal, and secondary alienation, the absence of an experience of or feeling about something abnormal. After having gone into everyday reality and how it can be so disturbed that alienation ensues, we go further into the experiences involved in both kinds of alienation and their positive and negative consequences. Secondary alienation is described as a common final path in the second stage of a human stress process. In the discussion, we pay attention to the social scientific tradition of alienation as result of an evil societal influence, which has turned out to be an unfortunate approach. Instead, we advocate an approach that conceives alienation as the outcome of a personal choice. Lastly we indicate shortly what can be done about secondary alienation.     

Interaction of stimulus dimensions in concept and choice processes

Four major types of interaction of stimulus dimensions based on perceptual research are described: integral, configural, separable, and asymmetric separable. Implications of these interactions for concept and choice processes are discussed. With regard to concept learning, it is argued that integral or configural interactions are desirable within the set of relevant and within the set of irrelevant dimensions used to generate stimuli, but that relevant dimensions should be separable from irrelevant dimensions. With regard to choice processes, integral or configural dimensions produce choices based on ordinary distance relations or equivalent parallel processing of dimensions. With separable dimensions, however, serial processing is at least possible; and such processing can lead to choices in which the subset of stimuli and the order of processing of dimensions affects the choice outcomes.