Experimental investigation of the subsonic high-altitude operation of the NASA Lewis 10- by 10-foot supersonic wind tunnel

An experimental investigation was conducted in the NASA Lewis 10- by 10-Foot Supersonic Wind Tunnel during subsonic tunnel operation in the aerodynamic cycle to determine the test section flow characteristics near the Advanced Turboprop Project propeller model plane of rotation. The investigation used an eight-probe pitot static flow survey rake to measure total and static pressures at two locations in the wind tunnel: the test section and the bellmouth section (upstream of the two-dimensional flexible-wall nozzle). A cone angularity probe was used to measure any flow angularity in the test section. The evaluation was conducted at tunnel Mach numbers from 0.10 to 0.35 and at three operating altitudes from 2,000 to 50,000 ft. which correspond to tunnel reference total pressures from 1960 to 245 psfa, respectively. The results of this experimental investigation indicate a total-pressure loss area in the center of the test section and a static-pressure gradient from the test section centerline to the wall. These total and static pressure differences were observed at all tunnel operating altitudes and diminished at lower tunnel velocities. The total-pressure loss area was also found in the bellmouth section, which indicates that the loss mechanism is not the tunnel flexible-wall nozzle. The flow in the test section is essentially axial since very small flow angles were measured. The results also indicate that a correction to the tunnel total and static pressures must be applied in order to determine accurate freestream conditions at the test section centerline

Program Review--Intentional Harmony: Managing Work and Life

Intentional Harmony: Balancing Work and Life, a program developed by the University of Illinois Cooperative Extension, is designed to address the effects of work stress on the employee, partnerships, parenting, friend and family relationships, and personal health. The program is comprehensive, concise, and research-based. There is some empirical evidence of the effectiveness of the parenting unit. Additional research with random assignment of participants to experimental and control groups is recommended. An evaluation instrument is provided

Review of Fathers Reading Every Day (FRED): Leader\u27s Guide

There is a growing need for science-based, effective programs that enhance child-father relationships. This article reviews Fathers Reading Every Day (FRED): Leader\u27s Guide. The authors found FRED to be clearly research-based, to address the need to improve father-child relationships, to have limited empirical evidence of program effectiveness, and to be ready for busy Cooperative Extension agents and other professionals to use. It is recommended that further pretest-posttest, experimental-control group studies be conducted on its effectiveness

A parametric shell analysis of the shuttle 51-L SRB AFT field joint

Following the Shuttle 51-L accident, an investigation was conducted to determine the cause of the failure. Investigators at the Langley Research Center focused attention on the structural behavior of the field joints with O-ring seals in the steel solid rocket booster (SRB) cases. The shell-of-revolution computer program BOSOR4 was used to model the aft field joint of the solid rocket booster case. The shell model consisted of the SRB wall and joint geometry present during the Shuttle 51-L flight. A parametric study of the joint was performed on the geometry, including joint clearances, contact between the joint components, and on the loads, induced and applied. In addition combinations of geometry and loads were evaluated. The analytical results from the parametric study showed that contact between the joint components was a primary contributor to allowing hot gases to blow by the O-rings. Based upon understanding the original joint behavior, various proposed joint modifications are shown and analyzed in order to provide additional insight and information. Finally, experimental results from a hydro-static pressurization of a test rocket booster case to study joint motion are presented and verified analytically

The X-ray Line Emission from the Supernova Remnant W49B

The Galactic supernova remnant W49B has one of the most impressive X-ray emission line spectra obtained with the Advanced Satellite for Cosmology and Astronomy (ASCA). We use both plasma line diagnostics and broadband model fits to show that the Si and S emission lines require multiple spectral components. The spectral data do not necessarily require individual elements to be spatially stratified, as suggested by earlier work, although when ASCA line images are considered, it is possible that Fe is stratified with respect to Si and S. Most of the X-ray emitting gas is from ejecta, based on the element abundances required, but is surprisingly close to being in collisional ionization equilibrium. A high ionization age implies a high internal density in a young remnant. The fitted emission measure for W49B indicates a minimum density of 2 cm^-3, with the true density likely to be significantly higher. W49B probably had a Type Ia progenitor, based on the relative element abundances, although a low-mass Type II progenitor is still possible. We find persuasive evidence for Cr and possibly Mn emission in the ASCA spectrum--the first detection of these elements in X-rays from a cosmic source.Comment: 22 pages incl 8 postscript figures, to appear in Ap

The search for novel analgesics: re-examining spinal cord circuits with new tools

In this perspective, we propose the absence of detailed information regarding spinal cord circuits that process sensory information remains a major barrier to advancing analgesia. We highlight recent advances showing that functionally discrete populations of neurons in the spinal cord dorsal horn play distinct roles in processing sensory information. We then discuss new molecular, electrophysiological, and optogenetic techniques that can be employed to understand how dorsal horn circuits process tactile and nociceptive information. We believe this information can drive the development of entirely new classes of pharmacotherapies that target key elements in spinal circuits to selectively modify sensory function and blunt pain

Incidence and diversity of mixed viruses lower in yam tubers and tuber sprouts compared with field leaf samples: Implications for virusfree planting material control strategy

Millions of people around the world, particularly in West Africa, depend on yam for food and income, however global yam production has been fluctuating since 2007. Virus infections contribute to yam yield losses and the occurrence of mixed virus infections is potentially catastrophic. Planting of certified virus-free/resistant tubers is advocated therefore knowledge of the role of yam planting material in the virus dynamics in yam fields is crucial for effective yam virus control. In this study, yam tubers bought from markets in six West African countries were planted in an insect proof screen-house. Leaf samples from the tuber sprouts were tested by ELISA and/or IC-PCR/IC-RT-PCR to determine the incidence of Yam mosaic virus, Yam mild mosaic virus, cucumber mosaic virus, and Dioscorea Bacilliform viruses. Yam tubers from Nigeria and Ghana, as well as yam leaves collected from yam fields in Nigeria were also tested. All the viruses assayed for were detected. Most of the virus infections detected in the tuber (83%) and tuber sprouts (95%) were single infections of either Dioscorea bacilliform viruses (DBV) or Yam mosaic virus (YMV). The incidence of mixed infection in the field samples (49.3%) was about 3 times and 10 times more than those detected in the tubers (17%) and the tuber sprouts (5%). These results suggest that other factors other than the tubers used as planting materials contribute to the vast incidence of mixed virus infections in yam fields. These factors must be properly appraised and be factored into any yam virus control strategy equation in order to achieve a sustainable yam production in West Africa in particular and the world in general

Analytical approximations for magnetic coupling coefficients between adjacent coils

This paper presents a simple yet novel two-dimensional modelling approach for approximating the coupling coefficient between neighbouring inductors as a function of co-planar separation and relative angular displacement. The approach employs simple geometric arguments to predict the effective magnetic flux between inductors. Two extreme coil geometry regimes are considered; planar coils (i.e. on printed circuit board), and solenoid coils, each with asymmetric ferrite cores about the central magnetic plane of the inductor. The proposed geometric approximation is used to predict the coupling coefficient between sensors as a function of separation distance and angular displacement and the results are validated against two-dimensional finite element modelling results. The analytical approximations show excellent agreement with the FE analysis, predicting comparable trends with changing separation and angular displacement, enabling best fitting to 2D FE and 3D numerical data with a residual standard deviation of less than 0.5% for the planar coil approximation. The work demonstrates the validity of the analytical approximation for predicting coupling behaviour between neighbouring coils. This has practical uses for the automated estimation of the physical separation between coils, or the curvature of surfaces they are rested or adhered to.</p