11,534 research outputs found

    The geometry and physical properties of exhaust clouds generated during the static firing of S-1C and S-2 rocket engines

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    An experimental program was conducted during the static firing of the S-1C stage 13, 14, and 15 rocket engines and the S-2 stage 13, 14, and 15 rocket engines. The data compiled during the experimental program consisted of photographic recordings of the time-dependent growth and diffusion of the exhaust clouds, the collection of meteorological data in the ambient atmosphere, and the acquisition of data on the physical structure of the exhaust clouds which were obtained by flying instrumented aircraft through the clouds. A new technique was developed to verify the previous measurements of evaporation and entrainment of blast deflector cooling water into the cloud. The results of the experimental program indicate that at the lower altitudes the rocket exhaust cloud or plume closely resembles a free-jet type of flow. At the upper altitudes, where the cloud is approaching an equilibrium condition, structure is very similar to a natural cumulus cloud

    Develop a land use-peak runoff classification system for highway engineering purposes

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    The author has identified the following significant results. Based on the detail study of the Sunkhaze Stream Watershed, it is believed that good detailed drainage studies can be derived from repetitive ERTS imagery. Land use maps tailored to hydrologic study can be prepared from ERTS imagery. Significant changes in the Sunkhaze Stream and Otter Stream Watersheds at spring flood conditions have given important information on the causes for flooding in the town of Bradley

    Multidisciplinary analysis for highway engineering purposes

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    There are no author-identified significant results in this report

    First-Order Vortex Lattice Melting and Magnetization of YBa2_2Cu3_3O$_{7-\delta}

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    We present the first non-mean-field calculation of the magnetization M(T)M(T) of YBa2_2Cu3_3O7δ_{7-\delta} both above and below the flux-lattice melting temperature Tm(H)T_m(H). The results are in good agreement with experiment as a function of transverse applied field HH. The effects of fluctuations in both order parameter ψ(r)\psi({\bf r}) and magnetic induction BB are included in the Ginzburg-Landau free energy functional: ψ(r)\psi({\bf r}) fluctuates within the lowest Landau level in each layer, while BB fluctuates uniformly according to the appropriate Boltzmann factor. The second derivative (2M/T2)H(\partial^2 M/\partial T^2)_H is predicted to be negative throughout the vortex liquid state and positive in the solid state. The discontinuities in entropy and magnetization at melting are calculated to be 0.034kB\sim 0.034\, k_B per flux line per layer and 0.0014\sim 0.0014~emu~cm3^{-3} at a field of 50 kOe.Comment: 11 pages, 4 PostScript figures in one uuencoded fil

    Surgery groups of the fundamental groups of hyperplane arrangement complements

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    Using a recent result of Bartels and Lueck (arXiv:0901.0442) we deduce that the Farrell-Jones Fibered Isomorphism conjecture in L-theory is true for any group which contains a finite index strongly poly-free normal subgroup, in particular, for the Artin full braid groups. As a consequence we explicitly compute the surgery groups of the Artin pure braid groups. This is obtained as a corollary to a computation of the surgery groups of a more general class of groups, namely for the fundamental group of the complement of any fiber-type hyperplane arrangement in the complex n-space.Comment: 11 pages, AMSLATEX file, revised following referee's comments and suggestions, to appear in Archiv der Mathemati

    Automotive Stirling engine development program

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    The study of high power kinematic Stirling engines for transportation use, testing of Mod I and Mod II Stirling engines, and component development activities are summarized. Mod II development testing was performed to complete the development of the basic engine and begin characterization of performance. Mod I engines were used for Mod II component development and to obtain independent party (U.S. Air Force) evaluation of Stirling engine vehicle performance

    Impeded Growth of Magnetic Flux Bubbles in the Intermediate State Pattern of Type I Superconductors

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    Normal state bubble patterns in Type I superconducting Indium and Lead slabs are studied by the high resolution magneto-optical imaging technique. The size of bubbles is found to be almost independent of the long-range interaction between the normal state domains. Under bubble diameter and slab thickness proper scaling, the results gather onto a single master curve. On this basis, in the framework of the "current-loop" model [R.E. Goldstein, D.P. Jackson and A.T. Dorsey, Phys. Rev. Lett. 76, 3818 (1996)], we calculate the equilibrium diameter of an isolated bubble resulting from the competition between the Biot-and-Savart interaction of the Meissner current encircling the bubble and the superconductor-normal interface energy. A good quantitative agreement with the master curve is found over two decades of the magnetic Bond number. The isolation of each bubble in the superconducting matrix and the existence of a positive interface energy are shown to preclude any continuous size variation of the bubbles after their formation, contrary to the prediction of mean-field models.Comment: \'{e}quipe Nanostructures Quantique

    Performance of LPG Storage Tanks on Ground Improved by Stone Columns

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    This paper describes the construction of four large tanks on poor soil conditions consisting of hydraulic fill placed over estuarine silt in Dublin port. The limited differential settlement that could be tolerated by the tanks required that they could not be placed on the existing ground. The optimum solution was found to be ground treatment using vibro-replacement with the formation of stone columns and compaction of the fill. The paper describes the design method used and the control tests. The predicted settlements are compared with settlement readings of the tanks following construction. These show that the chosen solution has performed well and satisfied the design requirements
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