4,691 research outputs found

    An approximate viscous shock layer technique for calculating chemically reacting hypersonic flows about blunt-nosed bodies

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    An approximate axisymmetric method was developed which can reliably calculate fully viscous hypersonic flows over blunt nosed bodies. By substituting Maslen's second order pressure expression for the normal momentum equation, a simplified form of the viscous shock layer (VSL) equations is obtained. This approach can solve both the subsonic and supersonic regions of the shock layer without a starting solution for the shock shape. The approach is applicable to perfect gas, equilibrium, and nonequilibrium flowfields. Since the method is fully viscous, the problems associated with a boundary layer solution with an inviscid layer solution are avoided. This procedure is significantly faster than the parabolized Navier-Stokes (PNS) or VSL solvers and would be useful in a preliminary design environment. Problems associated with a previously developed approximate VSL technique are addressed before extending the method to nonequilibrium calculations. Perfect gas (laminar and turbulent), equilibrium, and nonequilibrium solutions were generated for airflows over several analytic body shapes. Surface heat transfer, skin friction, and pressure predictions are comparable to VSL results. In addition, computed heating rates are in good agreement with experimental data. The present technique generates its own shock shape as part of its solution, and therefore could be used to provide more accurate initial shock shapes for higher order procedures which require starting solutions

    The addition of algebraic turbulence modeling to program LAURA

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    The Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) is modified to allow the calculation of turbulent flows. This is accomplished using the Cebeci-Smith and Baldwin-Lomax eddy-viscosity models in conjunction with the thin-layer Navier-Stokes options of the program. Turbulent calculations can be performed for both perfect-gas and equilibrium flows. However, a requirement of the models is that the flow be attached. It is seen that for slender bodies, adequate resolution of the boundary-layer gradients may require more cells in the normal direction than a laminar solution, even when grid stretching is employed. Results for axisymmetric and three-dimensional flows are presented. Comparison with experimental data and other numerical results reveal generally good agreement, except in the regions of detached flow

    Shadow writing and participant observation : a study of criminal justice social work around sentencing

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    The study of decision-making by public officials in administrative settings has been a mainstay of law and society scholarship for decades. The methodological challenges posed by this research agenda are well understood: how can socio-legal researchers get inside the heads of legal decision-makers in order to understand the uses of official discretion? This article describes an ethnographic technique the authors developed to help them penetrate the decision-making practices of criminal justice social workers in writing pre-sentence reports for the courts. This technique, called `shadow writing', involved a particular form of participant observation whereby the researcher mimicked the process of report writing in parallel with the social workers. By comparing these `shadow reports' with the real reports in a training-like setting, the social workers revealed in detail the subtleties of their communicative strategies embedded in particular reports and their sensibilities about report writing more generally

    The Effect of Individual Difference on the Continued Use of False Information: Intelligence and Personality

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    The current study aimed to assess whether individual differences in fluid intelligence, as measured by abstract reasoning, emotional intelligence, and the Big Five personality traits would predict susceptibility to the continued influence effect. A total of 29 undergraduate students at Brescia University College read a news story that contained both misinformation and a retraction and were then tested on that news story. Participants also completed three additional questionnaires measuring personality traits, emotional intelligence, and abstract reasoning. It was predicted that individuals with lower levels of fluid and emotional intelligence, as well as those who scored higher in neuroticism and extraversion would be the most susceptible to the continued influence effect. Results indicated that fluid intelligence, emotional intelligence, and the personality traits were not significant predictors of susceptibility to the continued influence effect, although individuals who exhibited higher levels of fluid intelligence were more likely to remember the retraction

    An interactive user-friendly approach to surface-fitting three-dimensional geometries

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    A surface-fitting technique has been developed which addresses two problems with existing geometry packages: computer storage requirements and the time required of the user for the initial setup of the geometry model. Coordinates of cross sections are fit using segments of general conic sections. The next step is to blend the cross-sectional curve-fits in the longitudinal direction using general conics to fit specific meridional half-planes. Provisions are made to allow the fitting of fuselages and wings so that entire wing-body combinations may be modeled. This report includes the development of the technique along with a User's Guide for the various menus within the program. Results for the modeling of the Space Shuttle and a proposed Aeroassist Flight Experiment geometry are presented

    User's Manual for the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA)

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    This user's manual provides detailed instructions for the installation and the application of version 4.1 of the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA). Also provides simulation of flow field in thermochemical nonequilibrium around vehicles traveling at hypersonic velocities through the atmosphere. Earlier versions of LAURA were predominantly research codes, and they had minimal (or no) documentation. This manual describes UNIX-based utilities for customizing the code for special applications that also minimize system resource requirements. The algorithm is reviewed, and the various program options are related to specific equations and variables in the theoretical development

    Translational Regulation of the DOUBLETIME/CKIδ/ε Kinase by LARK Contributes to Circadian Period Modulation

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    The Drosophila homolog of Casein Kinase I δ/ε, DOUBLETIME (DBT), is required for Wnt, Hedgehog, Fat and Hippo signaling as well as circadian clock function. Extensive studies have established a critical role of DBT in circadian period determination. However, how DBT expression is regulated remains largely unexplored. In this study, we show that translation of dbt transcripts are directly regulated by a rhythmic RNA-binding protein (RBP) called LARK (known as RBM4 in mammals). LARK promotes translation of specific alternative dbt transcripts in clock cells, in particular the dbt-RC transcript. Translation of dbt-RC exhibits circadian changes under free-running conditions, indicative of clock regulation. Translation of a newly identified transcript, dbt-RE, is induced by light in a LARK-dependent manner and oscillates under light/dark conditions. Altered LARK abundance affects circadian period length, and this phenotype can be modified by different dbt alleles. Increased LARK delays nuclear degradation of the PERIOD (PER) clock protein at the beginning of subjective day, consistent with the known role of DBT in PER dynamics. Taken together, these data support the idea that LARK influences circadian period and perhaps responses of the clock to light via the regulated translation of DBT. Our study is the first to investigate translational control of the DBT kinase, revealing its regulation by LARK and a novel role of this RBP in Drosophila circadian period modulation

    Integration as Service: Implications of Faith-Praxis Integration for Training

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    Faith-praxis integration should be given further attention as the integration of applied psychology and Christian theology proceeds. The authors outline a rationale for faith-praxis integration based upon patterns of mental health needs and resources in the U.S. and for a Kingdom mandate. Implications of a faith-praxis perspective for trainers of Christian psychologists are suggested in relation to a program’s missions statement, faculty, course work, practical training, research, and relationship to the community. Selected activities of existing Christian psychology training programs are included to illustrate these implications. Ongoing discussion is invited concerning this emerging area of integration

    Entry Dispersion Analysis for the Stardust Comet Sample Return Capsule

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    Stardust will be the first mission to return samples from beyond the Earth-Moon system. The sample return capsule, which is passively controlled during the fastest Earth entry ever, will land by parachute in Utah. The present study analyzes the entry, descent, and landing of the returning sample capsule. The effects of two aerodynamic instabilities are revealed (one in the high altitude free molecular regime and the other in the transonic/subsonic flow regime). These instabilities could lead to unacceptably large excursions in the angle-of-attack near peak heating and main parachute deployment, respectively. To reduce the excursions resulting from the high altitude instability, the entry spin rate of the capsule is increased. To stabilize the excursions from the transonic/subsonic instability, a drogue chute with deployment triggered by an accelerometer and timer is added prior to main parachute deployment. A Monte Carlo dispersion analysis of the modified entry (from which the impact of off-nominal conditions during the entry is ascertained) shows that the capsule attitude excursions near peak heating and drogue chute deployment are within Stardust program limits. Additionally, the size of the resulting 3-sigma landing ellipse is 83.5 km in downrange by 29.2 km in crossrange, which is within the Utah Test and Training Range boundaries
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