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81.
The determination of dynamic crack resistance curves from single specimen fracture tests requires information about the crack advance during the experiment. Here, attention is focused on crack resistance curves for nodular cast iron based on experimental data from instrumented Charpy tests. In order to estimate the actual crack length a key curve method (KCM) is employed. On the other hand, the Charpy impact tests were realized numerically using finite element calculations in conjunction with a continuum damage model (CDM) to simulate ductile crack growth. The parameters of the CDM model were determined from the experimental data of single specimen fracture tests. Equivalence between the experimental and the numerical realization of a fracture test was ensured by validating the predictions of the numerical simulations by means of low blow fracture tests. Comparison between the crack advance predicted by the numerical simulations and the results obtained using the proposed KCM shows a sufficiently well agreement with the actual crack length. Furthermore, crack resistance curves obtained from single specimen tests using either standard estimation schemes in conjunction with the KCM or numerical simulations are compared with the predictions based on low blow fracture tests.  相似文献   
82.
83.
In this paper we propose a new model for estimating the effective properties of regular hexagonal honeycombs. This model yields some new simple formulae which, in contrast to previous attempts, match the general invariant relations found by Vigdergauz in 1999. By comparing with numerical results, we also find some improved (but still simple) formulae which enable us to estimate the effective properties with an accuracy better than 1%, even for high density honeycombs.  相似文献   
84.
Ninety-seven couples completed questionnaires about their involvement in joint religious activities and their perceptions regarding the sanctification of marriage, including perceived sacred qualities of marriage and beliefs about the manifestation of God in marriage. In contrast to individual religiousness and religious homogamy (distal religious constructs), these proximal religious variables directly reflect an integration of religion and marriage, and they were associated with greater global marital adjustment, more perceived benefits from marriage, less marital conflict, more verbal collaboration, and less use of verbal aggression and stalemate to discuss disagreements for both wives and husbands. The proximal measures also added substantial unique variance (adjusted R2 change ranged from .06 to .48) to specific aspects of marital functioning after controlling demographic factors and distal religious variables in hierarchical regression analyses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
85.
Four studies demonstrate the psychometric adequacy and validity of scales designed to assess coping through emotional approach. In separate undergraduate samples, exploratory and confirmatory factor analyses of dispositional (Study 1) and situational (Study 3) coping item sets yielded 2 distinct emotional approach coping factors: emotional processing (i.e., active attempts to acknowledge and understand emotions) and emotional expression. The 2 scales yielded high internal consistency and test-retest reliability, as well as convergent and discriminant validity. A study (Study 2) of young adults and their parents established the scales' interjudge reliabilities. Longitudinal (Study 3) and experimental (Study 4) research supported the predictive validity of the emotional approach coping scales with regard to adjustment to stressful encounters. Findings highlight the utility of functionalist theories of emotion as applied to coping theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
86.
Electric utilities are under increasing pressure to provide better quality service to the customer. In the information age, even momentary interruptions are now unacceptable. The Central Iowa Power Cooperative (USA) has 10 years of experience using variable cross-section ACSR conductor (T2) in an attempt to improve line performance. This article presents a summary of the lessons learned during that time  相似文献   
87.
This article is concerned with the cyclic properties of 316L-type austenitic stainless at 300 and 77 K. The role of nitrogen alloying and of the temperature decrease is examined during low-cycle fatigue (LCF) and fatigue crack propagation. Fatigue resistance is enhanced by the addition of nitrogen in steel at both test temperatures. The results are discussed on the basis of micro-structural observations. Planar slip of dislocations is found in the nitrogen-containing steel and is favored by a decrease in test temperature. To some extent, the influence of interstitial nitrogen on the fatigue properties is related to its role in stabilizing austenite observed during cooling as well as during straining.  相似文献   
88.
Emphasizing research published in the past decade, this article presents a summary and evaluation of psychosocial investigations of women's reproductive health, with a focus on selected aspects of menstruation, pregnancy and birth, infertility, and menopause. In some areas, studies have focused on negative physical and psychological concomitants of these health issues. However, research reveals substantial individual variability, with most women adapting well to reproductive health changes. Although methodological and conceptual shortcomings have limited firm conclusions, research has advanced our understanding of the multivariate biological, psychological, and social influences on women's reproductive health and associated outcomes. Understanding and promoting women's reproductive health across the lifespan requires biopsychosocial approaches to research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
89.
A variety of different experimental results show substantial evidence that the order parameter in high-temperature superconducting copper oxides is not of pure d-wave symmetry, but that an s-wave component exists, which especially shows up in experiments that test the c-axis properties. These findings are modeled theoretically within a two-band model with interband interactions, where the superconducting order parameters in the two bands are allowed to differ in symmetry. It is found that the coupling of order parameters with different symmetries (s+d) leads to substantial enhancements of the superconducting transition temperature T c as compared to order parameters with only s-wave symmetry. An additional enhancement factor of T c is obtained from the coupling of the bands to the lattice where moderate couplings favor superconductivity while too strong couplings lead to electron (hole) localization and consequently suppress superconductivity.  相似文献   
90.
Four experiments investigated how people's perceptions about a group's (e.g., women's) vulnerability to a disease are influenced by information about the prevalence of the disease in a comparable group (e.g., men). Participants read symptom and prevalence information about fictitious diseases before answering questions regarding target group vulnerability. Participants used the prevalence rate for a nontarget group as an immediate comparison standard for intuitively interpreting the degree of vulnerability of a target group, resulting in robust contrast effects. Experiments 3 and 4 illustrated that these contrast effects can cause a person's intuitive perceptions about a group's vulnerability to selected diseases to conflict with his or her knowledge of the prevalence rates for the diseases. The results support a distinction between 2 components of psychological uncertainty--beliefs in objective probability and more intuitive perceptions of certainty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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