Space shuttle afterbody aerodynamics/plume simulation data summary

A series of parametric wind tunnel tests was conducted to provide a base for developing a simulation of afterbody/base aerodynamics for multibody/multibase rocket-powered vehicles (such as Space Shuttle) which use unheated air as the simulant gas in development wind tunnel tests. The tests described were parameterized on external configuration, nozzle internal configuration, base geometry, propulsion gas type, and freestream Mach number (0.5 to 3.5). The tests were conducted over a 4-year period. Presented in this report are the data and pertinent reference information necessary to perform an analysis which would lead to a simulation procedure. The type of data obtained during the tests described herein include model base afterbody, and nozzle internal surface static pressure distributions, model chamber pressure and temperature, and freestream conditions. Also included is a brief description of simulation procedures that were used by the Space Shuttle program

Cooler and bigger than thought? Planetary host stellar parameters from the InfraRed Flux Method

Effective temperatures and radii for 92 planet-hosting stars as determined from the InfraRed Flux Method (IRFM) are presented and compared with those given by other authors using different approaches. The IRFM temperatures we have derived are systematically lower than those determined from the spectroscopic condition of excitation equilibrium, the mean difference being as large as 110 K. They are, however, consistent with previous IRFM studies and with the colors derived from Kurucz and MARCS model atmospheres. Comparison with direct measurements of stellar diameters for 7 dwarf stars, which approximately cover the range of temperatures of the planet-hosting stars, suggest that the IRFM radii and temperatures are reliable in an absolute scale. A better understanding of the fundamental properties of the stars with planets will be achieved once this discrepancy between the IRFM and the spectroscopic temperature scales is resolved.Comment: 15 pages, 4 figures. Accepted for publication in Ap

Elemental Abundance Ratios in Stars of the Outer Galactic Disk. II. Field Red Giants

We summarize a selection process to identify red giants in the direction of the southern warp of the Galactic disk, employing VI_C photometry and multi-object spectroscopy. We also present results from follow-up high-resolution, high-S/N echelle spectroscopy of three field red giants, finding [Fe/H] values of about -0.5. The field stars, with Galactocentric distances estimated at 10 to 15 kpc, support the conclusion of Yong, Carney, & de Almeida (2005) that the Galactic metallicity gradient disappears beyond R_GC values of 10 to 12 kpc for the older stars and clusters of the outer disk. The field and cluster stars at such large distances show very similar abundance patterns, and, in particular, all show enhancements of the "alpha" elements O, Mg, Si, Ca, and Ti and the r-process element Eu. These results suggest that Type II supernovae have been significant contributors to star formation in the outer disk relative to Type Ia supernovae within the past few Gyrs. We also compare our results with those available for much younger objects. The limited results for the H II regions and B stars in the outer disk also suggest that the radial metallicity gradient in the outer disk is shallow or absent. The much more extensive results for Cepheids confirm these trends, and that the change in slope of the metallicity gradient may occur at a larger Galactocentric distance than for the older stars and clusters. However, the younger stars also show rising alpha element enhancements with increasing R_GC, at least beyond 12 kpc. These trends are consistent with the idea of a progressive growth in the size of the Galactic disk with time, and episodic enrichment by Type II supernovae as part of the disk's growth. [Abridged]Comment: Accepted for publication in A

Abundances and Kinematics of Field Halo and Disk Stars I: Observational Data and Abundance Analysis

We describe observations and abundance analysis of a high-resolution, high-S/N survey of 168 stars, most of which are metal-poor dwarfs. We follow a self-consistent LTE analysis technique to determine the stellar parameters and abundances, and estimate the effects of random and systematic uncertainties on the resulting abundances. Element-to-iron ratios are derived for key alpha, odd, Fe-peak, r- and s-process elements. Effects of Non-LTE on the analysis of Fe I lines are shown to be very small on the average. Spectroscopically determined surface gravities are derived that are generally close to those obtained from Hipparcos parallaxes.Comment: 41 pages, 7 Postscript figures. Accepted for publication in the A

Space shuttle: Static aerodynamic characteristics and control effectiveness of the GAC H-33 orbiter at Mach numbers from 0.6 to 4.96

A .003366 scale model of the Grumman H-33 orbiter was tested in the MSFC 14 inch Trisonic Wind Tunnel. Six-component aerodynamic force and moment data was recorded over a Mach number range of 0.6 to 4.96. Both pitch runs and yaw runs at various constant angles of attack were completed. The basic model configuration was investigated. The effects of a component build-up and of various control deflections were obtained. The elevons were deflected symmetrically and asymmetrically to determine elevator and aileron effectiveness. The rudder was tested both flared and unflared and the effects of deflections were determined in the flared case. The model was tested in pitch in two intervals. The first interval was from 0 to 20 deg. Then an adaptor was set to give the sting an offset angle and 20 to 40 deg angle of attack was obtained. Characteristics in sideslip were determined by varying sideslip angle from -4 deg to 10 deg with angle of attack set at 0 deg, 10 deg, 15 deg, and 30 deg

Oxygen Abundances in Two Metal-Poor Subgiants from the Analysis of the 6300 A Forbidden O I Line

Recent LTE analyses (Israelian et al. 1998 and Bosegaard et al. 1999) of the OH bands in the optical-ultraviolet spectra of nearby metal-poor subdwarfs indicate that oxygen abundances are generally higher than those previously determined. The difference increases with decreasing metallicity and reaches delta([O/Fe]) ~ +0.6 dex as [Fe/H] approaches -3.0. Employing high resolution (R = 50000), high S/N (~ 250) echelle spectra of the two stars found by Israelian et al. (1998) to have the highest [O/Fe]-ratios, viz, BD +23 3130 and BD +37 1458, we conducted abundance analyses based on about 60 Fe I and 7-9 Fe II lines. We determined from Kurucz LTE models the values of the stellar parameters, as well as abundances of Na, Ni, and the traditional alpha-elements, independent of the calibration of color vs $T_{eff}$ scales. We determined oxygen abundances from spectral synthesis of the stronger line (6300 A) of the [O I] doublet. The syntheses of the [O I] line lead to smaller values of [O/Fe], consistent with those found earlier among halo field and globular cluster giants. We obtain [O/Fe] = +0.35 +/- 0.2 for BD +23 3130 and +0.50 +/- 0.2 for BD +37 1458. In the former, the [O I] line is very weak (~ 1 mA), so that the quoted [O/Fe] value may in reality be an upper limit. Therefore in these two stars a discrepancy exists between the [O/Fe]- ratios derived from [O I] and the OH feature, and the origin of this difference remains unclear. Until the matter is clarified, we suggest it is premature to conclude that the ab initio oxygen abundances of old, metal-poor stars need to be revised drastically upward.Comment: 38 pages, 5 tables, 14 figures To appear in July 1999 AJ Updated April 16, 1999. Fixed typo

Legal Status Effects on Parent-Child Relationships and Parent Well-Being

Despite heightened levels of parenting stress and psychological distress experienced by many immigrant-origin families in the United States, little is known about the resiliency of Latinx families, particularly in today’s political climate. This research presents the results of a pilot study examining the effects of legal stressors on parent-child relationships and parent well-being in Latinx immigrant families. Taken from the Latinx Immigrant Family Stories and Strengths project, this mixed-methods study was informed by the integrative risk and resilience model for understanding the adaptation of immigrant-origin children and youth (Suarez-Orozco, Motti- Stefanidi, Marks, & Katsiaficas, 2018). The pilot included a sample of 30 adult parent participants with various legal statuses and migration experiences. Qualitatively, participants shared their experiences of legal vulnerability, fears or concerns of deportation, and coping mechanisms. Quantitatively, scores for parental stress, psychological distress, post-traumatic stress disorder (PTSD) symptoms, and resilience were collected. Following a, sequential explanatory design (Creswell et al., 2003), quantitative data were analyzed for relationships among study variables. A case-oriented research comparative strategy (Eckstein, 1975; Mahoney & Goertz, 2004; George & Bennett, 2005; Gerring, 2006) was then used to qualitatively examine the migration and resiliency experiences of the two cases with lowest and highest levels of resilience according to the Brief Resilience Scale (BRS; Smith et al., 2008) scores. Results suggest that, on average, parents experienced normal to high rates of parenting-related stress, low levels of psychological distress, moderate to severe symptoms of PTSD, and low to average levels of resiliency. Parents identifying as undocumented experienced higher rates of parental stress (r = 0.49, p\u3c.05) and psychological distress (r = 0.41, p\u3c.05) compared to their liminally legal and documented peers. Although the trauma experienced by many immigrant-origin parents in the study was markedly high, resilience was fostered and expressed, and was exemplified through our high-resilience case analysis. Participants’ stories expressed throughout this study spoke volumes about the complex and often times traumatic lived experiences that many foreign- born parents face. Implications for comprehensive, detailed, and longitudinal future research is discussed.https://scholarscompass.vcu.edu/gradposters/1106/thumbnail.jp

High Reynolds number test of a NACA 651-213, a equals 0.5 airfoil at transonic speeds

Wind-Tunnel tests were conducted in the Lockheed-Georgia Company's compressible flow facility to determine the transonic two-dimensional aerodynamic characteristics of a NACA 65 sub 1-213 a = 0.50 airfoil. The results are correlated with data obtained in the NASA-Langley 8-foot transonic pressure tunnel and the NAE high Reynolds number 15x60-inch two-dimensional test facility. The tests were conducted over a Mach number range from 0.60 to 0.80 and an angle of attack range from -1 deg to 8 deg. Reynolds numbers, based on the airfoil chord, were varied

The role of type 4 phosphodiesterases in generating microdomains of cAMP: Large scale stochastic simulations

Cyclic AMP (cAMP) and its main effector Protein Kinase A (PKA) are critical for several aspects of neuronal function including synaptic plasticity. Specificity of synaptic plasticity requires that cAMP activates PKA in a highly localized manner despite the speed with which cAMP diffuses. Two mechanisms have been proposed to produce localized elevations in cAMP, known as microdomains: impeded diffusion, and high phosphodiesterase (PDE) activity. This paper investigates the mechanism of localized cAMP signaling using a computational model of the biochemical network in the HEK293 cell, which is a subset of pathways involved in PKA-dependent synaptic plasticity. This biochemical network includes cAMP production, PKA activation, and cAMP degradation by PDE activity. The model is implemented in NeuroRD: novel, computationally efficient, stochastic reaction-diffusion software, and is constrained by intracellular cAMP dynamics that were determined experimentally by real-time imaging using an Epac-based FRET sensor (H30). The model reproduces the high concentration cAMP microdomain in the submembrane region, distinct from the lower concentration of cAMP in the cytosol. Simulations further demonstrate that generation of the cAMP microdomain requires a pool of PDE4D anchored in the cytosol and also requires PKA-mediated phosphorylation of PDE4D which increases its activity. The microdomain does not require impeded diffusion of cAMP, confirming that barriers are not required for microdomains. The simulations reported here further demonstrate the utility of the new stochastic reaction-diffusion algorithm for exploring signaling pathways in spatially complex structures such as neurons

What lifestyle changes should we recommend for the patient with newly diagnosed hypertension?

Hypertensive patients should reduce sodium intake (strength of recommendation [SOR]: A). The Dietary Approaches to Stop Hypertension diet (DASH diet)--with salt restriction and increased fruit, vegetable, calcium, and potassium intake--reduces blood pressure and should be recommended (SOR: A). Aerobic exercise is effective in the general, as well as elderly, populations for reducing blood pressure (SOR: A). Patients should be encouraged to reduce alcohol consumption (SOR: A). Evidence that weight loss is significantly associated with blood pressure reduction is inconclusive (SOR: C). Smoking cessation should be encouraged for all hypertensive patients for prevention of cardiovascular disease (SOR: A)