488 research outputs found

    Alleviating Stress In Police Agencies

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    Policestress has been examined in many studies, many of which have focused upon thedevelopment of prevention and treatment programs for the police officers(Maslach, 1982; Maslach & Jackson, 1979; Mitchell, 1983; Mitchell &Everly, 1993). The trend of combating stress began with the police agenciesusing employee assistance programs, funding conferences, conducting research,and establishing prevention programs, but the fact remains that the health ofpolice officers and their families becomes a large concern as most officerstend not use free counseling due to concerns regarding confidentiality and thecompetence of the counselors. An example of one program is the New JerseyCOP-2-COP confidential hotline for police officers and their families (Ussery& Waters, 2006). COP-2-COP was a volunteer program and its usefulness wasseen post-September 11, 2001, in its response to the needs of the survivors ofthe World Trade Center disaster and also after the New Orleans disaster in theCritical Incident Stress Debriefing process after Hurricane Katrina.  Police stress can have a bad influence onpolice performance and can cause many problems such as poor job performance,increased accidents, sleep disturbances, marital discord, domestic violence,posttraumatic stress disorder, depression, suicide, alcohol and other drugabuse, ulcers and other digestive disorders, respiratory ailments, andcardiovascular disease

    The Impact Of Job-Related Stressors On Incidents Of Excessive Force By Police Officers

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    The present study addresses the relationship between job-related stressors and incidents of police misconduct, a concept that has largely been neglected in policing literature. Manzoni and Eisner’s conceptualization of stress-strain theory provided the foundation for the research. Specifically, this study examines individual differences in the perception of how job-related stressors such as departmental leadership, departmental policies and regulations, and departmental climate are related to incidents of police misconduct expressed through the exercise of excessive force. This quantitative survey design employed the Police Survey of Job Related Stress (PSJRS) among a convenience sample of 94 active police officers (49 African American and 45 European) from a southern U.S. state. T-tests and the Mann-Whitney test were used to document statistically significant differences between white and African American officers across the perceived connection linking the core PSJRS dimensions of job-related stressors to excessive force misconduct. The results promote positive social change by reinforcing social bonds between police and communities and creating safer places to live.

    Analysis of Bonded Joints Between the Facesheet and Flange of Corrugated Composite Panels

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    This paper outlines a method for the stress analysis of bonded composite corrugated panel facesheet to flange joints. The method relies on the existing HyperSizer Joints software, which analyzes the bonded joint, along with a beam analogy model that provides the necessary boundary loading conditions to the joint analysis. The method is capable of predicting the full multiaxial stress and strain fields within the flange to facesheet joint and thus can determine ply-level margins and evaluate delamination. Results comparing the method to NASTRAN finite element model stress fields are provided illustrating the accuracy of the method

    Micromechanics and Piezo Enhancements of HyperSizer

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    The commercial HyperSizer aerospace-composite-material-structure-sizing software has been enhanced by incorporating capabilities for representing coupled thermal, piezoelectric, and piezomagnetic effects on the levels of plies, laminates, and stiffened panels. This enhancement is based on a formulation similar to that of the pre-existing HyperSizer capability for representing thermal effects. As a result of this enhancement, the electric and/or magnetic response of a material or structure to a mechanical or thermal load, or its mechanical response to an applied electric or magnetic field can be predicted. In another major enhancement, a capability for representing micromechanical effects has been added by establishment of a linkage between HyperSizer and Glenn Research Center s Micromechanics Analysis Code With Generalized Method of Cells (MAC/GMC) computer program, which was described in several prior NASA Tech Briefs articles. The linkage enables Hyper- Sizer to localize to the fiber and matrix level rather than only to the ply level, making it possible to predict local failures and to predict properties of plies from those of the component fiber and matrix materials. Advanced graphical user interfaces and database structures have been developed to support the new HyperSizer micromechanics capabilities

    Spherical Cryogenic Hydrogen Tank Preliminary Design Trade Studies

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    A structural analysis, sizing optimization, and weight prediction study was performed by Collier Research Corporation and NASA Glenn on a spherical cryogenic hydrogen tank. The tank consisted of an inner and outer wall separated by a vacuum for thermal insulation purposes. HyperSizer (Collier Research and Development Corporation), a commercial automated structural analysis and sizing software package was used to design the lightest feasible tank for a given overall size and thermomechanical loading environment. Weight trade studies were completed for different panel concepts and metallic and composite material systems. Extensive failure analyses were performed for each combination of dimensional variables, materials, and layups to establish the structural integrity of tank designs. Detailed stress and strain fields were computed from operational temperature changes and pressure loads. The inner tank wall is sized by the resulting biaxial tensile stresses which cause it to be strength driven, and leads to an optimum panel concept that need not be stiffened. Conversely, the outer tank wall is sized by a biaxial compressive stress field, induced by the pressure differential between atmospheric pressure and the vacuum between the tanks, thereby causing the design to be stability driven and thus stiffened to prevent buckling. Induced thermal stresses become a major sizing driver when a composite or hybrid composite/metallic material systems are used for the inner tank wall for purposes such as liners to contain the fuel and reduce hydrogen permeation

    Progressive Failure Analysis of Composite Stiffened Panels

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    A new progressive failure analysis capability for stiffened composite panels has been developed based on the combination of the HyperSizer stiffened panel design/analysis/optimization software with the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC). MAC/GMC discretizes a composite material s microstructure into a number of subvolumes and solves for the stress and strain state in each while providing the homogenized composite properties as well. As a result, local failure criteria may be employed to predict local subvolume failure and the effects of these local failures on the overall composite response. When combined with HyperSizer, MAC/GMC is employed to represent the ply level composite material response within the laminates that constitute a stiffened panel. The effects of local subvolume failures can then be tracked as loading on the stiffened panel progresses. Sample progressive failure results are presented at both the composite laminate and the composite stiffened panel levels. Deformation and failure model predictions are compared with experimental data from the World Wide Failure Exercise for AS4/3501-6 graphite/epoxy laminates

    Preliminary Structural Sizing and Alternative Material Trade Study of CEV Crew Module

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    This paper presents the results of a preliminary structural sizing and alternate material trade study for NASA s Crew Exploration Vehicle (CEV) Crew Module (CM). This critical CEV component will house the astronauts during ascent, docking with the International Space Station, reentry, and landing. The alternate material design study considers three materials beyond the standard metallic (aluminum alloy) design that resulted from an earlier NASA Smart Buyer Team analysis. These materials are graphite/epoxy composite laminates, discontinuously reinforced SiC/Al (DRA) composites, and a novel integrated panel material/concept known as WebCore. Using the HyperSizer (Collier Research and Development Corporation) structural sizing software and NASTRAN finite element analysis code, a comparison is made among these materials for the three composite CM concepts considered by the 2006 NASA Engineering and Safety Center Composite Crew Module project

    Galaxy Cluster Pressure Profiles as Determined by Sunyaev Zel'dovich Effect Observations with MUSTANG and Bolocam I: Joint Analysis Technique

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    We present a technique to constrain galaxy cluster pressure profiles by jointly fitting Sunyaev-Zel'dovich effect (SZE) data obtained with MUSTANG and Bolocam for the clusters Abell 1835 and MACS0647. Bolocam and MUSTANG probe different angular scales and are thus highly complementary. We find that the addition of the high resolution MUSTANG data can improve constraints on pressure profile parameters relative to those derived solely from Bolocam. In Abell 1835 and MACS0647, we find gNFW inner slopes of γ=0.36−0.21+0.33\gamma = 0.36_{-0.21}^{+0.33} and γ=0.38−0.25+0.20\gamma = 0.38_{-0.25}^{+0.20}, respectively when α\alpha and β\beta are constrained to 0.86 and 4.67 respectively. The fitted SZE pressure profiles are in good agreement with X-ray derived pressure profiles.Comment: 12 pages, 12 figures. Submitted to Ap
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