Cracks in glass electrical connector headers removed by dry blasting with fine abrasive

Cracking that causes pressure leakage in glass connector headers can be alleviated by manipulating the pin bridgewire connectors. This initiates the surface and meniscus cracks. Dry blasting the header surface with a fine abrasive then removes the cracks

Low-speed wind tunnel investigation of the lateral-directional characterisitcs of a large-scale variable wing-sweep fighter model in the high-lift configuration

The low-speed characteristics of a large-scale model of the F-14A aircraft were studied in tests conducted in the Ames Research Center 40- by 80-Foot Wind Tunnel. The primary purpose of the present tests was the determination of lateral-directional stability levels and control effectiveness of the aircraft in its high-lift configuration. Tests were conducted at wing angles of attack between minus 2 deg and 30 deg and with sideslip angles between minus 12 deg and 12 deg. Data were taken at a Reynolds number of 8.0 million based on a wing mean aerodynamic chord of 2.24 m (7.36 ft). The model configuration was changed as required to show the effects of direct lift control (spoilers) at yaw, yaw angle with speed brake deflected, and various amounts and combinations of roll control

An aerodynamic investigation of two 1.83-meter-diameter fan systems designed to drive a subsonic wind tunnel

An experimental, aerodynamic investigation was made of two 1.83 m diameter fan systems which are being considered for the repowered drive section of the 40- by 80-foot wind tunnel at NASA Ames Research Center. One system was low speed, the other was high speed. The low speed fan was tested at various stagger angles from 32.9 deg to 62.9 deg. At a fan blade stagger angle of 40.8 deg and operating at a tip speed of 1155 m/sec, the low speed fan developed 207.3 m of head. The high speed fan had a design blade stagger angle of 56.2 deg and was tested at this stagger angle only. The high speed fan operating at 191.5 m/sec developed 207.3 m of head. Radial distributions of static pressure coefficients, total pressure coefficients, and angles of swirl are presented. Radial surveys were conducted at four azimuth locations in front of the fan, and repeated downstream of the fan. Data were taken for various flow control devices and for two inlet contraction lengths

Environmental legislation as a driver of design

and other research output

Measurement of Prandtl number and thermal conductivity Summary report

Prandtl numbers and thermal conductivity of air, argon, and hydrocarbon fuel combustion product

An experimental investigation of two large annular diffusers with swirling and distorted inflow

Two annular diffusers downstream of a nacelle-mounted fan were tested for aerodynamic performance, measured in terms of two static pressure recovery parameters (one near the diffuser exit plane and one about three diameters downstream in the settling duct) in the presence of several inflow conditions. The two diffusers each had an inlet diameter of 1.84 m, an area ratio of 2.3, and an equivalent cone angle of 11.5, but were distinguished by centerbodies of different lengths. The dependence of diffuser performance on various combinations of swirling, radially distorted, and/or azimuthally distorted inflow was examined. Swirling flow and distortions in the axial velocity profile in the annulus upstream of the diffuser inlet were caused by the intrinsic flow patterns downstream of a fan in a duct and by artificial intensification of the distortions. Azimuthal distortions or defects were generated by the addition of four artificial devices (screens and fences). Pressure recovery data indicated beneficial effects of both radial distortion (for a limited range of distortion levels) and inflow swirl. Small amounts of azimuthal distortion created by the artificial devices produced only small effects on diffuser performance. A large artificial distortion device was required to produce enough azimuthal flow distortion to significantly degrade the diffuser static pressure recovery

High rate production of polarized 3He with meta-stability exchange method

Keywords: polarized 3He, meta-stability exchange, infrared laserComment: 4 figures, submitted to J. Phys. Soc. Jpn

Three level atom optics via the tunneling interaction

Three level atom optics (TLAO) is introduced as a simple, efficient and robust method to coherently manipulate and transport neutral atoms. The tunneling interaction among three trapped states allows to realize the spatial analog of the stimulated Raman adiabatic passage (STIRAP), coherent population trapping (CPT), and electromagnetically induced transparency (EIT) techniques. We investigate a particular implementation in optical microtrap arrays and show that under realistic parameters the coherent manipulation and transfer of neutral atoms among dipole traps could be realized in the millisecond range.Comment: 5 pages, 6 figure

Film cooling following injection through inclined circular tubes

Film cooling following air injection through inclined flat plate holes into turbulent boundary laye

Cutaneous Silent Period Characteristics are Dependent on the Organization of Upper Limb Muscles

abstractCutaneous silent periods (CSPs) are inhibitory spinal reflexes mediated by small diameter A-δ fibers, serving to protect the body from harmful stimuli (Leis et al., 1992; Kofler, 2003). Currently, CSPs are believed to only inhibit the extensor muscles of the upper limb halting motions such as reaching, while exciting flexor muscles to withdraw the limb. The present study sought to determine if CSPs could be evoked in both extensor and flexor muscles of the upper limb, thereby providing further insight into the organization of the spinal circuitry associated with this reflex. 22 subjects performed contractions with seven muscles from the hand, forearm, upper arm, and shoulder while muscle activity was recorded with electromyography. Subjects were electrically stimulated (10x perceptual threshold) with 20 individual pulses delivered to each digit II (radial nerve) and digit V (ulnar nerve) of the right hand during each contraction. Results demonstrated significant main effects (p<0.001) across muscles for the key dependent variables of the CSP: onsets (F[6,21] = 15.42, p <0.001), durations (F[6,21] = 65.39, p <0.001), and % of suppression (F[6,21] = 91, p <0.001), similarly for both nerves stimulated. Distal muscles presented with the earliest onset times, longest duration of inhibition, and largest amount of inhibition. Moving proximally, the onset times became later with duration and the amount of inhibition decreasing. Linear regressions showed that the distance of the muscle from the spinal cord (cm) was a significant predictor of the duration (digit II r2 = 0.43; digit V r2 = 0.46) and amount of inhibition (digit II r2 = 0.51; digit V r2 = 0.48). The results demonstrate the occurrence of CSPs throughout the upper limb, with the greatest inhibition of distal muscles, leading us to hypothesize that the corticospinal tract, specifically direct cortico-motorneuronal connections, are directly influenced by the inhibitory input