486 research outputs found

    A covariant multiple scattering series for elastic projectile-target scattering

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    A covariant formulation of the multiple scattering series for the optical potential is presented. The case of a scalar nucleon interacting with a spin zero isospin zero A-body target through meson exchange, is considered. It is shown that a covariant equation for the projectile-target t-matrix can be obtained which sums the ladder and crossed ladder diagrams efficiently. From this equation, a multiple scattering series for the optical potential is derived, and it is shown that in the impulse approximation, the two-body t-matrix associated with the first order optical potential is the one in which one particle is kept on mass-shell. The meaning of various terms in the multiple scattering series is given. The construction of the first-order optical potential for elastic scattering calculations is described

    Split Quaterionic Representation of SDYM (SU(1,1) Instantons in \u3ci\u3eS\u3c/i\u3e\u3csup\u3e2-\u3c/sup\u3e × \u3ci\u3eS\u3c/i\u3e\u3csup\u3e2+\u3c/sup\u3e

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    Using split‐quaternions, we find explicit SDYM SU(1,1) instanton solutions in S2- × S2+ which is the conformal compactification of the semi‐Euclidean 4‐spacetime R2+2 of split signature (-,-,+,+). It is also shows that SDYM and ASDYM fields in S2- × S2+ can be described as simple split-quaternionic 2-forms

    Confining potential in momentum space

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    A method is presented for the solution in momentum space of the bound state problem with a linear potential in r space. The potential is unbounded at large r leading to a singularity at small q. The singularity is integrable, when regulated by exponentially screening the r-space potential, and is removed by a subtraction technique. The limit of zero screening is taken analytically, and the numerical solution of the subtracted integral equation gives eigenvalues and wave functions in good agreement with position space calculations

    Solution of two-body relativistic bound state equations with confining plus Coulomb interactions

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    Studies of meson spectroscopy have often employed a nonrelativistic Coulomb plus Linear Confining potential in position space. However, because the quarks in mesons move at an appreciable fraction of the speed of light, it is necessary to use a relativistic treatment of the bound state problem. Such a treatment is most easily carried out in momentum space. However, the position space Linear and Coulomb potentials lead to singular kernels in momentum space. Using a subtraction procedure we show how to remove these singularities exactly and thereby solve the Schroedinger equation in momentum space for all partial waves. Furthermore, we generalize the Linear and Coulomb potentials to relativistic kernels in four dimensional momentum space. Again we use a subtraction procedure to remove the relativistic singularities exactly for all partial waves. This enables us to solve three dimensional reductions of the Bethe-Salpeter equation. We solve six such equations for Coulomb plus Confining interactions for all partial waves

    Radiation Transport and Shielding for Space Exploration and High Speed Flight Transportation

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    Transportation of ions and neutrons in matter is of direct interest in several technologically important and scientific areas, including space radiation, cosmic ray propagation studies in galactic medium, nuclear power plants and radiological effects that impact industrial and public health. For the proper assessment of radiation exposure, both reliable transport codes and accurate data are needed. Nuclear cross section data is one of the essential inputs into the transport codes. In order to obtain an accurate parametrization of cross section data, theoretical input is indispensable especially for processes where there is little or no experimental data available. In this grant period work has been done on the studies of the use of relativistic equations and their one-body limits. The results will be useful in choosing appropriate effective one-body equation for reaction calculations. Work has also been done to improve upon the data base needed for the transport codes used in the studies of radiation transport and shielding for space exploration and high speed flight transportation. A phenomenological model was developed for the total absorption cross sections valid for any system of charged and/or uncharged collision pairs for the entire energy range. The success of the model is gratifying. It is being used by other federal agencies, national labs and universities. A list of publications based on the work during the grant period is given below and copies are enclosed with this report

    Why Do I Write the Way I Write

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    Panel: Why I Write The Way I D

    The design of semi-submersibles for minimum vertical motion

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    Summary available: p. [1

    The blood glucose lowering effect of Malaysian Tinospora crispa in rats

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    Diabetes is defined as a chronic hyperglycemia which should be countered by the effective, safe and readily available hypoglycemic agents. Herbal is among alternatives that has been used by society for years but lacks of documented evidences. Tinospora crispa (TC) is enriched by phytochemicals which potentially reduce blood glucose thus is useful for diabetic patients. This study aimed to investigate the potency of TC inreducing blood sugar and body weight. It involved 30 healthy rats divided into 5 groups namely: normal control, normal fed with TC extract, diabetic, TC-treated diabetic (dose 500 mg/kg w/w), and vitamin E-traeted diabetic rats (60 IU). The body weight and fasting blood glucose were measured each week for 1 month. The administration of TC extract 500 mg/kg (w/w) helps to maintain body weight in diabetic rats and reduce the fasting blood glucose. TC is highly potent as hypoglycemic agents therefore needed to be explored further
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