A Search for Hydroxylamine (NH_2OH) toward Select Astronomical Sources

Observations of 14 rotational transitions of hydroxylamine (NH_2OH) using the NRAO 12 m telescope on Kitt Peak are reported toward IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M. Although recent models suggest the presence of NH_2OH in high abundance, these observations resulted in non-detection. Upper limits are calculated to be as much as six orders of magnitude lower than those predicted by models. Possible explanations for the lower-than-expected abundance are explored

Comparison of the full potential and Euler formulations for computing transonic airfoil flows

A quantitative comparison between the Euler and full potential formulations with respect to speed and accuracy is presented. The robustness of the codes used is tested by a number of transonic airfoil cases. The computed results are from four transonic airfoil computer codes. The full potential codes use fully implicit iteration algorithms. The first Euler code uses a fully implicit ADI iteration scheme. The second Euler code uses an explicit Runge Kutta time stepping algorithm which is enhanced by a multigrid convergence acceleration scheme. Quantitative comparisons are made using various plots of lift coefficient versus the average mesh spacing along the airfoil. Besides yielding an asymptotic limit to the lift coefficient, these results also demonstrate the truncation error behavior of the various codes. Quantitative conclusions regarding the full potential and Euler formulations with respect to accuracy, speed, and robustness can be presented

Developing a Meaningful Fourth Amendment Approach to Automobile Investigatory Stops

Police officers throughout the nation face the practical application of Fourth Amendment\u27 protections in the automobile investigatory stop context daily in a wide variety of settings. Nevertheless, the Supreme Court has yet to articulate a functional analytical approach to automobile investigatory stops. This lack of guidance is particularly troublesome when one considers that the Framers specifically designed the Fourth Amendment to prevent government officials from conducting investigations in an oppressive, unreasonable manner. The problem is not simply theoretical but has manifested itself through confusion in the lower courts. The lack of response from the Court on this issue has left lower courts not only disagreeing over the appropriate approach courts should use to analyze the pretext issue but also questioning the existence and content of pretext doctrine

Navier-Stokes computations for circulation control airfoils

Navier-Stokes computations of subsonic to transonic flow past airfoils with augmented lift due to rearward jet blowing over a curved trailing edge are presented. The approach uses a spiral grid topology. Solutions are obtained using a Navier-Stokes code which employs an implicit finite difference method, an algebraic turbulence model, and developments which improve stability, convergence, and accuracy. Results are compared against experiments for no jet blowing and moderate jet pressures and demonstrate the capability to compute these complicated flows

Teaching About Racial and Ethnic Diversity in Social Work Education: A Systematic Review

Little of social work literature provides evidence of best teaching practices for preparing social work students to work with clients from historically excluded racial and ethnic groups. A systematic literature review was conducted to assess studies published in the United States during the 10-year period (2007-2016) that examined: (1) social work educators\u27 pedagogical interventions for teaching about racial and ethnic diversity, (2) components of those interventions, (3) methodological designs to evaluate the interventions, and (4) the students\u27 learning outcomes. Following the systematic review protocol, the authors identified and assessed twenty-five studies (qualitative, quantitative, and mixed-methods). The studies reflected a variety of teaching interventions, such as diversity courses and projects, instructional technology, and cultural immersion programs. While many reported positive student learning outcomes, as a whole, the studies lacked methodological rigor and sound theoretical grounding. Although social work education attempts to prepare students for multicultural practice, the field lacks an intentional and systematic approach to teaching about racial and ethnic diversity and evaluating learning outcomes in social work students. There is an urgency to expand the empirical evidence on social work diversity education, particularly concerning teaching about race, racism, and Whiteness

High-Lift OVERFLOW Analysis of the DLR-F11 Wind Tunnel Model

In response to the 2nd AIAA CFD High Lift Prediction Workshop, the DLR-F11 wind tunnel model is analyzed using the Reynolds-averaged Navier-Stokes flow solver OVERFLOW. A series of overset grids for a bracket-off landing configuration is constructed and analyzed as part of a general grid refinement study. This high Reynolds number (15.1 million) analysis is done at multiple angles-of-attack to evaluate grid resolution effects at operational lift levels as well as near stall. A quadratic constitutive relation recently added to OVERFLOW for improved solution accuracy is utilized for side-of-body separation issues at low angles-of-attack and outboard wing separation at stall angles. The outboard wing separation occurs when the slat brackets are added to the landing configuration and is a source of discrepancy between the predictions and experimental data. A detailed flow field analysis is performed at low Reynolds number (1.35 million) after pressure tube bundles are added to the bracket-on medium grid system with the intent of better understanding bracket/bundle wake interaction with the wing's boundary layer. Localized grid refinement behind each slat bracket and pressure tube bundle coupled with a time accurate analysis are exercised in an attempt to improve stall prediction capability. The results are inconclusive and suggest the simulation is missing a key element such as boundary layer transition. The computed lift curve is under-predicted through the linear range and over-predicted near stall, and the solution from the most complete configuration analyzed shows outboard wing separation occurring behind slat bracket 6 where the experiment shows it behind bracket 5. These results are consistent with most other participants of this workshop

Aerodynamic Optimization of Rocket Control Surface Geometry Using Cartesian Methods and CAD Geometry

Aerodynamic design is an iterative process involving geometry manipulation and complex computational analysis subject to physical constraints and aerodynamic objectives. A design cycle consists of first establishing the performance of a baseline design, which is usually created with low-fidelity engineering tools, and then progressively optimizing the design to maximize its performance. Optimization techniques have evolved from relying exclusively on designer intuition and insight in traditional trial and error methods, to sophisticated local and global search methods. Recent attempts at automating the search through a large design space with formal optimization methods include both database driven and direct evaluation schemes. Databases are being used in conjunction with surrogate and neural network models as a basis on which to run optimization algorithms. Optimization algorithms are also being driven by the direct evaluation of objectives and constraints using high-fidelity simulations. Surrogate methods use data points obtained from simulations, and possibly gradients evaluated at the data points, to create mathematical approximations of a database. Neural network models work in a similar fashion, using a number of high-fidelity database calculations as training iterations to create a database model. Optimal designs are obtained by coupling an optimization algorithm to the database model. Evaluation of the current best design then gives either a new local optima and/or increases the fidelity of the approximation model for the next iteration. Surrogate methods have also been developed that iterate on the selection of data points to decrease the uncertainty of the approximation model prior to searching for an optimal design. The database approximation models for each of these cases, however, become computationally expensive with increase in dimensionality. Thus the method of using optimization algorithms to search a database model becomes problematic as the number of design variables is increased