Wind tunnel model and method

The design and development of a wind tunnel model equipped with pressure measuring devices are discussed. The pressure measuring orifices are integrally constructed in the wind tunnel model and do not contribute to distortions of the aerodynamic surface. The construction of a typical model is described and a drawing of the device is included

Determination of the Phonon Spectrum of Polyethylene by Neutron Scattering

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70180/2/JCPSA6-43-3-1079-1.pd

Addendum: One‐Speed Neutron Transport in Two Adjacent Half‐Spaces

The interface current for the problem of two half‐spaces with a constant source in one half‐space is obtained in closed form.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70010/2/JMAPAQ-5-12-1804-1.pd

Inelastic Neutron Scattering by Gaseous O2

The magnetic contributions to neutron diffraction by molecular oxygen have been studied both experimentally and theoretically. We extend the theoretical studies by performing a calculation of the magnetic interaction in the inelastic neutron cross section for gaseous O2. The magnetic inelastic cross section for O2 is significantly different from the nuclear inelastic cross section due to the lack of spherical symmetry in the magnetic‐moment distribution about each oxygen nucleus. It is expected from these results that the inelastic cross section for O2 will provide more information about the magnetic‐moment distribution than the angular distribution. We present representative calculations to indicate the size and nature of the magnetic contribution to the inelastic cross section.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71223/2/JCPSA6-49-2-890-1.pd

One‐Speed Neutron Transport in Two Adjacent Half‐Spaces

Using Case's method for solving the one‐speed transport equation with isotropic scattering, the Milne problem solution, the solution for a constant source in one half‐space, and the Green's function solution are obtained for two adjacent half‐spaces. These problems have been solved previously by other methods. Here the derivations are greatly simplified by using Case's method.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71048/2/JMAPAQ-5-5-668-1.pd

Relationships among Generalized Phase‐Space Distributions

The generalized phase‐space distributions, including the Wigner distribution, are presented in terms of expected values of generating operators. A generalization of the Weyl correspondence is obtained to provide expressions for generalized Wigner equivalents. Finally, rather simple relationships are obtained connecting the generalized phase‐space distributions to the Wigner distribution; and similar relationships are obtained for the generalized Wigner equivalents. In particular, it appears that, among the class considered, there is no reason to use any distribution other than the Wigner for performing any calculations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69967/2/JMAPAQ-10-2-233-1.pd

Technique for the integral casting of pressure instrumentation in wind-tunnel models

Wind tunnel models are cast around core consisting of array of tubing. Principal advantage of technique is that greater number of pressure orifices are easily installed, without compromising aerodynamic shape of model. Technique reduces construction cost by about 50 percent

On the fermi approximation in thermal neutron scattering

The Fermi approximation and all higher order corrections are derived for the cross section for thermal neutron scattering from aggregates of atoms. The first order correction is shown to reduce to the result obtained by Lippmann and Schwinger in the special case that the scatterer is a single bound proton. The magnitude of the correction is estimated for an arbitrary number of scattering atoms, and it is shown to be approximately proportional to the inverse of the separation between atoms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32155/1/0000210.pd

Quantum Statistics and Slow Neutron Scattering by Gases

A surprisingly simple expression in ``closed form'' for the cross section d2σ/dΩdϵ for the scattering of thermal neutrons (including polarized neutrons) from an ideal quantum gas is derived. This result extends the work of Van Hove on the quantum gas. An expansion is obtained for dσ/dϵ. The case of elastic scattering is treated separately. From these expressions is obtained a criterion for ignoring the statistics of the scatterer in favor of classical (Boltzmann) statistics. This criterion should have some validity for weakly interacting systems. It is shown that the effects of statistics on the neutron cross section for a helium‐4 gas range from 5% or less for the noninteracting gas up to as much as 40% for the interacting system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70882/2/JCPSA6-47-12-4923-1.pd

Chemical binding effects in resonance--Potential interference scattering for harmonic crystals

The neutron scattering cross section which is the quantity directly measured in experiments is given by the absolute square of the scattering amplitude. For energies near a resonance, this yields three terms: potential, resonant and interference. In this paper, we deal with the interference neutron scattering cross section which is written in terms of a three-point correlation function. This function is calculated for the ideal gas and harmonic crystal models. For short collision times, the interference result for harmonic crystals is the same as the ideal gas but it has an effective temperature. This is the same effective temperature as was previously found for absorption and pure resonant processes. Therefore, the interference scattering cross section can be treated in the same way resonant scattering and absorption are treated using an ideal gas result with the usual effective temperature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29521/1/0000608.pd