Comparison of aerodynamic noise from three nose-cylinder combinations

Results of experiments with three different cylinder and blunted nose combinations are discussed. Combinations include smooth cylinder with single 15 deg cone, smooth cylinder with double cone of 25 and 10 deg, and longitudinally corrugated cylinder with similar double cone

A general method to determine the stability of compressible flows

Several problems were studied using two completely different approaches. The initial method was to use the standard linearized perturbation theory by finding the value of the individual small disturbance quantities based on the equations of motion. These were serially eliminated from the equations of motion to derive a single equation that governs the stability of fluid dynamic system. These equations could not be reduced unless the steady state variable depends only on one coordinate. The stability equation based on one dependent variable was found and was examined to determine the stability of a compressible swirling jet. The second method applied a Lagrangian approach to the problem. Since the equations developed were based on different assumptions, the condition of stability was compared only for the Rayleigh problem of a swirling flow, both examples reduce to the Rayleigh criterion. This technique allows including the viscous shear terms which is not possible in the first method. The same problem was then examined to see what effect shear has on stability

Vegetation and Grazing in the St. Katherine Protectorate, South Sinai, Egypt

Plants were surveyed in the St. Katherine Protectorate of South Sinai, Egypt. The most frequently recorded plant species include: Artemisia herba-alba, Artemisia judaica, Fagonia arabica, Fagonia mollis, Schismus barbatus, Stachys aegyptiaca, Tanacetum sinaicum, Teucrium poliumand Zilla spinosa. Dominant plant families were Compositae, Graminae, Labiatae, and Leguminosae. Communities with a high grazing pressure had a lower overall plant vigour. A strong negative correlation was found between plant vigour and grazing pressure. Twelve plantfamilies showed heavy grazing pressure, including Resedaceae, Caryophyllaceae, Polygalaceae, Juncaceae, Solanaceae, Geraniaceae, Ephedraceae, Globulariaceae, Urticaceae, Moraceae, Plantaginaceae, and Salicaceae

A technique for determining daytime atmospheric oxide above 50 km from backscattered ultraviolet measurements

Airglow from gamma band resonance fluorescence of nitric oxide near 255 nm is calculated at several solar zenith angles. Data from the Nimbus 4 BUV wavelengths 273.5 to 287.6 nm is used to estimate the Rayleigh and ozone scattering contributions to the BUV 255.5 nm data and the remaining signal is attributed to NO airglow. The low solar zenith angle contributions by NO is less than 0.5%, and the high latitude/high zenith angle contribution exceeds 5%. This technique allows for estimating NO content above 50 km, as well as partitioning that content between the mesosphere and thermosphere

A low-mass stellar companion of the planet host star HD75289

We report on the detection of a new low-mass stellar companion of HD75289, a G0V star that harbors one known radial-velocity planet (Udry et al. 2000). Comparing an image of 2MASS with an image we obtained with SofI at the ESO 3.58m NTT three years later, we detected a co-moving companion located 21.465+-0.023arcsecs (621+-10AU at 29pc) east of HD75289. A second SofI image taken 10 months later confirmed the common proper motion of HD75289B with its host star. The infrared spectrum and colors of the companion are consistent with an M2 to M5 main-sequence star at the distance of HD75289. No further (sub)stellar companion down to H = 19mag could be detected. With the SofI detection limit we can rule out additional stellar companions beyond 140AU and substellar companions with masses m > 0.050Msun from 400AU up to 2000AU.Comment: accepted in A&

Gust penetration loads and elastic vehicle response for Saturn 5 launch vehicles

Analysis of gust penetration loads and associated elastic vehicle response of Saturn 5 launch vehicles AS-505 through AS-508 penetrating sinusoidal gust

From Russia with Love: The Impact of Relocated Firms on Incumbent Survival

We identify the impact of local firm concentration on incumbent performance with a quasi natural experiment. When Germany was divided after World War II, many firms in the machine tool industry fled the Soviet occupied zone to prevent expropriation. We show that the regional location decisions of these firms upon moving to western Germany were driven by non-economic factors and heuristics rather than existing industrial conditions. Relocating firms increased the likelihood of incumbent failure in destination regions, a pattern that differs sharply from new entrants. We further provide evidence that these effects are due to increased competition for local resources.Agglomeration, competition, firm dynamics, labor, Germany

An evaluation of aft-end ignition for solid propellant rocket motors

Performance evaluation of solid propellant rocket motor ignition to determine igniter design and parameters to avoid overpressurizatio