Constitutive modeling for isotropic materials (HOST)

The results of the first year of work on a program to validate unified constitutive models for isotropic materials utilized in high temperature regions of gas turbine engines and to demonstrate their usefulness in computing stress-strain-time-temperature histories in complex three-dimensional structural components. The unified theories combine all inelastic strain-rate components in a single term avoiding, for example, treating plasticity and creep as separate response phenomena. An extensive review of existing unified theories is given and numerical methods for integrating these stiff time-temperature-dependent constitutive equations are discussed. Two particular models, those developed by Bodner and Partom and by Walker, were selected for more detailed development and evaluation against experimental tensile, creep and cyclic strain tests on specimens of a cast nickel base alloy, B19000+Hf. Initial results comparing computed and test results for tensile and cyclic straining for temperature from ambient to 982 C and strain rates from 10(exp-7) 10(exp-3) s(exp-1) are given. Some preliminary date correlations are presented also for highly non-proportional biaxial loading which demonstrate an increase in biaxial cyclic hardening rate over uniaxial or proportional loading conditions. Initial work has begun on the implementation of both constitutive models in the MARC finite element computer code

Metastatic tumors to the jaws : A report of eight new cases

Purpose: The purpose of the article is to present 8 new cases of metastatic tumors occurring in the jawbones, their clinical features , diagnostic workup and management. Patients and methods: The records of 8 patients with metastatic jaw lesions were reviewd. Demographic data, presenting symptoms, primary tumor site, radiographic findings, bone scintigraphy , histopathology and clinical management were analyzed. Results: The patients , ranged in age from 44 to 80 years, with a mean of 64.5 years. The primary malignant sites were: the lung , the breast , the rectum, the thyroid, the uterus and the parotid gland . The mandible was the site of oral involvement in seven cases and the maxilla in one. There was no gender difference with respect to the oral site affected. The clinical jaw presentations were: exophytic soft tissue mass, paresthesia of the lower lip and a periapical lesion The provided treatment protocols were: chemotherapy , radiotherapy and chemotherapy, surgery and chemotherapy and supportive care only. In one case the jaw lesion was the first indication of an unknown malignancy at a distant primary site. Conclusions: Metastatic jaw lesions are uncommon. Paresthesia of the lower lip and the chin is a sinister sign for patients with a metastatic jaw lesion. In view of these cases it can be said that meticulous work-up of of jaw lesions suspected of being metastatic, may be life saving or extend the patient?s survival period

How do Changes in Family Role Status Impact Employees? An empirical investigation

Purpose – Despite the proliferation of work–family research, a thorough understanding of family role status changes (e.g. the gaining of elder or child caregiving responsibilities) remain under-theorized and under-examined. The purpose of this paper is to conceptualize various forms of family role status changes and examine the ways in which these changes influence various employee outcomes. Design/methodology/approach – Data were collected as part of the work–family health study. Using a longitudinal, three-wave study with two-time lags of 6 months (n = 151 family role status changes; n = 392 individuals with family role stability), this study uses one-way analysis of variance to compare mean differences across groups and multilevel modeling to examine the predictive effects of family role status changes. Findings Overall, experiences of employees undergoing a family role status change did not differ significantly from employees whose family role status remained stable over the same 12-month period. Separation/divorce predicted higher levels of family-to-work conflict. Originality/value The work raises important considerations for organizational science and human resource policy research to better understand the substantive effects of family role status changes on employee well-being

N=2 Supersymmetric Scalar-Tensor Couplings

We determine the general coupling of a system of scalars and antisymmetric tensors, with at most two derivatives and undeformed gauge transformations, for both rigid and local N=2 supersymmetry in four-dimensional spacetime. Our results cover interactions of hyper, tensor and double-tensor multiplets and apply among others to Calabi-Yau threefold compactifications of Type II supergravities. As an example, we give the complete Lagrangian and supersymmetry transformation rules of the double-tensor multiplet dual to the universal hypermultiplet.Comment: 23 pages, LaTeX2e with amsmath.sty; v2: corrected typos and added referenc

Free-Boundary Dynamics in Elasto-plastic Amorphous Solids: The Circular Hole Problem

We develop an athermal shear-transformation-zone (STZ) theory of plastic deformation in spatially inhomogeneous, amorphous solids. Our ultimate goal is to describe the dynamics of the boundaries of voids or cracks in such systems when they are subjected to remote, time-dependent tractions. The theory is illustrated here for the case of a circular hole in an infinite two-dimensional plate, a highly symmetric situation that allows us to solve much of the problem analytically. In spite of its special symmetry, this example contains many general features of systems in which stress is concentrated near free boundaries and deforms them irreversibly. We depart from conventional treatments of such problems in two ways. First, the STZ analysis allows us to keep track of spatially heterogeneous, internal state variables such as the effective disorder temperature, which determines plastic response to subsequent loading. Second, we subject the system to stress pulses of finite duration, and therefore are able to observe elasto-plastic response during both loading and unloading. We compute the final deformations and residual stresses produced by these stress pulses. Looking toward more general applications of these results, we examine the possibility of constructing a boundary-layer theory that might be useful in less symmetric situations.Comment: 30 pages (preprint format), 9 figure

Work-Family Conflict, Family-Supportive Supervisor Behaviors (FSSB), and Sleep Outcomes

Although critical to health and well-being, relatively little research has been conducted in the organizational literature on linkages between the work-family interface and sleep. Drawing on Conservation of Resources theory, we use a sample of 623 information technology workers to examine the relationships between work-family conflict, family-supportive supervisor behaviors (FSSB), and sleep quality and quantity. Validated wrist actigraphy methods were used to collect objective sleep quality and quantity data over a one week period of time, and survey methods were used to collect information on self-reported work-family conflict, FSSB, and sleep quality and quantity. Results demonstrated that the combination of predictors (i.e., work-to-family conflict, family-to-work conflict, FSSB) was significantly related to both objective and self-report measures of sleep quantity and quality. Future research should further examine the work-family interface to sleep link and make use of interventions targeting the work-family interface as a means for improving sleep health

Prostate-specific antigen bounce predicts for a favorable prognosis following brachytherapy: a meta-analysis.

PURPOSE: Controversy exists whether the prostate-specific antigen (PSA) bounce phenomenon following definitive radiation for prostate cancer has prognostic significance. Here, we perform a meta-analysis to determine the association between PSA bounce and biochemical control after brachytherapy alone. MATERIAL AND METHODS: We reviewed Medline, EMBASE, and CENTRAL citations through February 2012. Studies that recorded biochemical failure rates in bouncers and non-bouncers were included. Hazard ratios describing the impact of bounce on biochemical failure were extracted directly from the studies or calculated from survival curves. Pooled estimates were obtained using the inverse variance method. A random effects model was used in cases of significant effect heterogeneity (p \u3c 0.10 using Q test). RESULTS: The final analysis included 3011 patients over 6 studies treated with brachytherapy. Meta-analysis revealed that patients experiencing PSA bounce after brachytherapy, conferred a decreased risk of biochemical failure (random effects model HR = 0.42, 95% CI: 0.30-0.59; p \u3c 0.001). CONCLUSIONS: Our meta-analysis determined that PSA bounce predicts for improved biochemical control following brachytherapy. To our knowledge, this is the first study describing this effect