2,527 research outputs found

    Pseudospectra of the heat operator Pencil

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    This article undertakes an analysis of the one-dimensional heat equation, wherein the Dirichlet condition is applied at the left end and Neumann condition at the right end. The heat equation is restructured as a non-self-adjoint 2×22\times 2 unbounded block operator matrix pencil. The spectral, pseudospectral, and (n,ϵ)(n,\epsilon)-pseudospectral enclosures of the 2×22\times 2 unbounded block operator matrix pencil are explored to scrutinize the heat operator pencil. The plots of the discretized equation are depicted to illustrate the observations

    A Cultural Resources Survey for Medina Electric Cooperative, Inc., in Uvalde, Medina, and Frio Counties, Texas

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    The Center for Archaeological Research (CAR), The University of Texas at San Antonio (UTSA), under contract with Alexander Utility Engineering, Inc., (letter dated May 5, 1980), conducted an archaeological survey for the Medina Electric Cooperative, Inc. Although the CAR was contracted in May 1980, at the request of Medina Electric Cooperative, Inc., the actual survey was not carried out until February 25-March 1, 1981. The survey, which was conducted in three neighboring south Texas counties (Fig. 1), was concentrated along proposed electrical distribution lines at D1Hanis in Medina County, north of Uvalde in Uvalde County, and southwest of Pearsall in Frio County. General supervision of the project was provided by Dr. Thomas R. Hester, Director, and Jack D. Eaton, Associate Director, of the CAR-UTSA. The project was carried out by Augustine and Elizabeth Frkuska, Center staff archaeologists

    An application of Martingale convergence theorem to analyse company data

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    Martingale Convergence Theorem, in a slightly general form, when applied to the process of investor's fortune tells that an investor with a limited aim of enhancing her fortune k-fold will, in due course, either attain her aim or lose the entire initial investment. We verify and apply this theorem to analyse certain company data

    DNA binding proteins of rat thigh muscle: purification and characterization of an endonuclease

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    Two major DNA binding proteins of molecular weights 34,000 and 38,000 have been identified in the 30,000 g supernatant (S-30) fraction of rat thigh muscle extracts. The presence of 38 KD DNA binding protein in the muscle S-30 could be demonstrated only if Triton X-100 treated extracts were used for Afinity chromatography suggesting that this protein may be a membrane associated DNA binding protein. The 38 KD DNA binding protein differed from the 34 KD DNA binding protein also in its chromatographic behaviour in DE-52 columns in which the 38 KD protein was retained, while the 34 KD protein came out in the flow-through in an electrophoretically pure form. The 34 KD DNA binding protein can also be purified by precipitation with MgCl2. Incubation of 0 · 15 M NaCl eluates (containing the 38 KD and/or 34 KD DNA binding protein) in the presence of 100 mM Mg2+ resulted in the specific precipitation of the 34 KD protein. Prolonged incubation (30 days) of the 0 · 15 Ì NaCl eluates containing the two DNA binding proteins at 4°C led to the preferential degradation of the 34 KD DNA binding protein. Nitrocellulose filter binding assays indicated selective binding of purified 34 KD protein to ss DNA. Purified 34 KD DNA binding protein cleaved pBR 322 supercoiled DNA, and electrophoresis of the cleavage products in agarose gels revealed a major DNA band corresponding to the circular form of DNA

    Integrating aerodynamics and structures in the minimum weight design of a supersonic transport wing

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    An approach is presented for determining the minimum weight design of aircraft wing models which takes into consideration aerodynamics-structure coupling when calculating both zeroth order information needed for analysis and first order information needed for optimization. When performing sensitivity analysis, coupling is accounted for by using a generalized sensitivity formulation. The results presented show that the aeroelastic effects are calculated properly and noticeably reduce constraint approximation errors. However, for the particular example selected, the error introduced by ignoring aeroelastic effects are not sufficient to significantly affect the convergence of the optimization process. Trade studies are reported that consider different structural materials, internal spar layouts, and panel buckling lengths. For the formulation, model and materials used in this study, an advanced aluminum material produced the lightest design while satisfying the problem constraints. Also, shorter panel buckling lengths resulted in lower weights by permitting smaller panel thicknesses and generally, by unloading the wing skins and loading the spar caps. Finally, straight spars required slightly lower wing weights than angled spars
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