Jet array impingement with crossflow-correlation of streamwise resolved flow and heat transfer distributions

Correlations for heat transfer coefficients for jets of circular offices and impinging on a surface parallel to the jet orifice plate are presented. The air, following impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the heat transfer (impingement) surface. The downstream jets are subjected to a crossflow originating from the upstream jets. Impingement surface heat transfer coefficients resolved to one streamwise jet orifice spacing, averaged across the channel span, are correlated with the associated individual spanwise orifice row jet and crossflow velocities, and with the geometric parameters

Indicators of School Crime and Safety: 2012

Our nation's schools should be safe havens for teaching and learning, free of crime and violence. Any instance of crime or violence at school not only affects the individuals involved, but also may disrupt the educational process and affect bystanders, the school itself, and the surrounding community.Establishing reliable indicators of the current state of school crime and safety across the nation and regularly updating and monitoring these indicators is important in ensuring the safety of our nation's students. This is the aim of Indicators of School Crime and Safety. This report is the fifteenth in a series of annual publications produced jointly by the National Center for Education Statistics (NCES), Institute of Education Sciences (IES), in the U.S. Department of Education, and the Bureau of Justice Statistics (BJS) in the U.S. Department of Justice. This report presents the most recent data available on school crime and student safety. The indicators in this report are based on information drawn from a variety of data sources, including national surveys of students, teachers, and principals. Sources include results from the School-Associated Violent Deaths Study, sponsored by the U.S. Department of Education, the Department of Justice, and the Centers for Disease Control and Prevention; the National Crime Victimization Survey and School Crime Supplement to the survey, sponsored by the BJS and NCES, respectively; the Youth Risk Behavior Survey, sponsored by the Centers for Disease Control and Prevention; and the Schools and Staffing Survey and School Survey on Crime and Safety, both sponsored by NCES. The most recent data collection for each indicator varied by survey, from 2007 to 2011. Each data source has an independent sample design, data collection method, and questionnaire design, or is the result of a universe data collection. All comparisons described in this report are statistically significant at the .05 level. Additional information about methodology and the datasets analyzed in this report may be found in appendix A. This report covers topics such as victimization, teacher injury, bullying and cyber-bullying, school conditions, fights, weapons, availability and student use of drugs and alcohol, and student perceptions of personal safety at school. Indicators of crime and safety are compared across different population subgroups and over time. Data on crimes that occur away from school are offered as a point of comparison where available

Applying electron backscattering diffraction to macroscopic residual stress characterisation in a dissimilar weld

AbstractDissimilar metal welds are complicated in nature because of the complex microstructure characteristics in the weld fusion zone. It is often necessary to know the phase distribution in a dissimilar metal weld especially at the interface such as fusion zone and heat affected zone to be able to predict the behaviour of the joint and its fitness for service. In this paper, a dissimilar metal weld made between ferritic/martensitic modified 9Cr-1Mo steel (P91) and austenitic AISI 316LN stainless steel using autogenous electron beam (EB) welding was analysed. The weld fusion zone has a local segregation of bcc and fcc phases. The EBSD technique was applied to determine the volume fractions of each of these phases in the weld fusion zone. This information was incorporated into the analysis of neutron diffraction data from the weld zone, and the macro-scale residual stresses were calculated from phase-specific stresses arising from the welding process. The results indicate that the overall macroscopic residual stress distribution in the weld centre is predominantly compressive in nature driven by the solid-state phase transformation of the weld pool during rapid cooling, with tensile peaks pushed adjacent to the heat affected zone (HAZ)/Parent boundaries on both sides of the fusion zone