Design Considerations for a Free Space Transportation and Work Station Capsule

A concept for a low cost, low development risk Work Station Capsule for manned extra-vehicular operations is presented. Requirements for such a capsule are established and a conceptual design is outlined. The result is a low cost design providing the astronaut with improved protection and mobility and the means to make his activities more effective and safer. Operational considerations with emphasis on handling of emergencies are discussed. The authors conclude that such a design represents a highly desirable interim approach as a supplement to safe extra-vehicular operations

Convergence in measure under Finite Additivity

We investigate the possibility of replacing the topology of convergence in probability with convergence in $L^1$. A characterization of continuous linear functionals on the space of measurable functions is also obtained

MAD ABOUT BLUE: AN EMPIRICAL COMPARISON OF MINIMUM ABSOLUTE DEVIATIONS AND ORDINARY LEAST SQUARES ESTIMATES OF CONSUMER SURPLUS

This research evaluates methods for estimating consumer surplus from recreation demand models. MAD regression and MIMIC structural modeling are the primary tools employed. The results from simulated and actual data indicate that MAD regression outperforms OLS. Additionally, the analysis shows that well-defined, stable benefit-transfer functions can be developed.Consumer/Household Economics, Research Methods/ Statistical Methods,

Effects of Zeeman spin splitting on the modular symmetry in the quantum Hall effect

Magnetic-field-induced phase transitions in the integer quantum Hall effect are studied under the formation of paired Landau bands arising from Zeeman spin splitting. By investigating features of modular symmetry, we showed that modifications to the particle-hole transformation should be considered under the coupling between the paired Landau bands. Our study indicates that such a transformation should be modified either when the Zeeman gap is much smaller than the cyclotron gap, or when these two gaps are comparable.Comment: 8 pages, 4 figure

Linear vs. nonlinear effects for nonlinear Schrodinger equations with potential

We review some recent results on nonlinear Schrodinger equations with potential, with emphasis on the case where the potential is a second order polynomial, for which the interaction between the linear dynamics caused by the potential, and the nonlinear effects, can be described quite precisely. This includes semi-classical regimes, as well as finite time blow-up and scattering issues. We present the tools used for these problems, as well as their limitations, and outline the arguments of the proofs.Comment: 20 pages; survey of previous result

The vector-valued big q-Jacobi transform

Big $q$-Jacobi functions are eigenfunctions of a second order $q$-difference operator $L$. We study $L$ as an unbounded self-adjoint operator on an $L^2$-space of functions on $\mathbb R$ with a discrete measure. We describe explicitly the spectral decomposition of $L$ using an integral transform $\mathcal F$ with two different big $q$-Jacobi functions as a kernel, and we construct the inverse of $\mathcal F$.Comment: 35 pages, corrected an error and typo

Nuclear model tests with neutron resonance data

Previous determinations of the level density parameters, a, as derived from analyses of resonance parameter data, were carried out on the basis of the Gilbert-Cameron theoretical relation for the spin dispersion parameter, {sigma}. However, other different theoretical expressions for {sigma} have been derived previously on the basis of various nuclear models, such as the Fermi gas model, the unified Bohr-Mottelson model with and without inclusion of nucleon pairing correlations, and the Hartree-Fock model. The different expressions for {sigma} would impact the derivation of the a parameter. Because of these considerations, a new examination of the level density parameter, devoid of a reliance on a theoretical expression for {sigma}, is of great importance in various computations in the fields of reactor physics, astrophysics, and spallation neutrons. Here, the spin dispersion parameter of the level density formula, {sigma}, as determined from the spin dependent level spacings of neutron resonances, is compared with theoretical expressions and found to be in agreement with the results of Ericson. On the basis of the present results, the level density parameters, a, for a few nuclides were then derived and found to be lower than previous determinations by about 20%. The impact of the present findings on the LAHET calculations of neutron yields from thick targets of W is discussed

Breit Equation with Form Factors in the Hydrogen Atom

The Breit equation with two electromagnetic form-factors is studied to obtain a potential with finite size corrections. This potential with proton structure effects includes apart from the standard Coulomb term, the Darwin term, retarded potentials, spin-spin and spin-orbit interactions corresponding to the fine and hyperfine structures in hydrogen atom. Analytical expressions for the hyperfine potential with form factors and the subsequent energy levels including the proton structure corrections are given using the dipole form of the form factors. Numerical results are presented for the finite size corrections in the 1S and 2S hyperfine splittings in the hydrogen atom, the Sternheim observable $D_{21}$ and the 2S and 2P hyperfine splittings in muonic hydrogen. Finally, a comparison with some other existing methods in literature is presented.Comment: 24 pages, Latex, extended version, title change

Dipole binding in a cosmic string background due to quantum anomalies

We propose quantum dynamics for the dipole moving in cosmic string background and show that the classical scale symmetry of a particle moving in cosmic string background is still restored even in the presence of dipole moment of the particle. However, we show that the classical scale symmetry is broken due to inequivalent quantization of the the non-relativistic system. The consequence of this quantum anomaly is the formation of bound state in the interval \xi\in(-1,1). The inequivalent quantization is characterized by a 1-parameter family of self-adjoint extension parameter \Sigma. We show that within the interval \xi\in(-1,1), cosmic string with zero radius can bind the dipole and the dipole does not fall into the singularity.Comment: Accepted for publication in Phys. Rev.