38,710 research outputs found
Computer program determines exact two-sided tolerance limits for normal distributions
Computer program determines by numerical integration the exact statistical two-sided tolerance limits, when the proportion between the limits is at least a specified number. The program is limited to situations in which the underlying probability distribution for the population sampled is the normal distribution with unknown mean and variance
Noise tests on an externally blown flap with the engine in front of the wing
Noise tests were conducted with a nozzle exhausting over a small scale model of an externally blown flap (EBF) lift-augmentation system, with exhaust impingement on the wing leading edge. Two series of tests were conducted: with wing leading edge inside the nozzle; and with leading edge set back from the nozzle exit plane 1 diameter on the jet axis. The results indicated no significant differences in spectral shape, level, or directivity pattern. Static lift and thrust tests were conducted on the same model indicated considerable flow attachment on both configurations, with slightly greater attachment and turning for the wing outside the nozzle. Finally, a comparison with engine-above- and engine-below-the-wing EBF's tested by previous investigators shows the acoustic performance of the configurations tested for this report to lie between the other two
Acoustic tests of a 15.2 centimeter-diameter potential flow convergent nozzle
An experimental investigation of the jet noise radiated to the far field from a 15.2-cm-diam potential flow convergent nozzle has been conducted. Tests were made with unheated airflow over a range of subsonic nozzle exhaust velocities from 62 to 310m/sec. Mean and turbulent velocity measurements in the flow field of the nozzle exhaust indicated no apparent flow anomalies. Acoustic measurements yielded data uncontaminated by internal and/or background noise to velocities as low as 152m/sec. Finally, no significantly different acoustic characteristics between the potential flow nozzle and simple convergent nozzles were found
Experimental measurements of expanding storable-propellant products simulated by combustion of gaseous reactants
Gaseous reactant combustion simulation of dimethylhydrazine and hydrazine fuel system for nonequilibrium expansion studie
Fighting Novel Diseases amidst Humanitarian Crises
Humanitarian crises are becoming more prevalent and, frequently, more complex, in zones of mis-governance, lack of government presence, and even active conflict, marked by public mistrust and insecurity. The WHO and other health emergency responders lack the capacities and mandate to adequately respond. The current Ebola outbreak in an area of an active insurgency in the Democratic Republic of the Congo is just such a crisis. The State Department has banned U.S. personnel from the outbreak zone due to safety concerns, leaving the population feeling abandoned, potentially increasing the threat to the few brave health workers who remain.
We need is to rethink health emergency response during complex crises and devise new strategies. We offer a blueprint for responding to health emergencies amidst complex humanitarian crises. This blueprint includes peacekeepers who have the mandate and modalities fit for the purpose of quelling a health emergency; “smart” diplomacy to negotiate with belligerents and community members to ensure health and humanitarian worker safety; and deploying all needed health, security, and diplomatic assets. We also call for international development assistance for health, including to support states in developing core public health capacities, creating inclusive health systems, and meeting other need like clean water and nutritious food. Political actors will need to assume their responsibilities if humanitarians and health workers are to carry out theirs
Thirring Solitons in the presence of dispersion
The effect of dispersion or diffraction on zero-velocity solitons is studied
for the generalized massive Thirring model describing a nonlinear optical fiber
with grating or parallel-coupled planar waveguides with misaligned axes. The
Thirring solitons existing at zero dispersion/diffraction are shown numerically
to be separated by a finite gap from three isolated soliton branches. Inside
the gap, there is an infinity of multi-soliton branches. Thus, the Thirring
solitons are structurally unstable. In another parameter region (far from the
Thirring limit), solitons exist everywhere.Comment: 12 pages, Latex. To appear in Phys. Rev. Let
Medical Information Management System (MIMS): A generalized interactive information system
An interactive information system is described. It is a general purpose, free format system which offers immediate assistance where manipulation of large data bases is required. The medical area is a prime area of application. Examples of the system's operation, commentary on the examples, and a complete listing of the system program are included
Noise data from tests of a 1.83 meter (6-ft-) diameter variable-pitch 1.2-pressure-ratio fan (QF-9)
Acoustic and aerodynamic data for a 1.83-meter (6-ft.) diameter fan suitable for a quiet engine for short-takeoff-and-landing (STOL) aircraft are documented. The QF-9 rotor blades had an adjustable pitch feature which provided a means for testing at several rotor blade setting angles, including one for reverse thrust. The fan stage incorporated features for low noise. Far-field noise around the fan was measured without acoustic suppression over a range of operating conditions for six different rotor blade setting angles in the forward thrust configuration, and for one in the reverse configuration. Complete results of one-third-octave band analysis of the data are presented in tabular form. Also included are power spectra, data referred to the source, and sideline perceived noise levels
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