Engineering Commons^™

Optimal Linear Coding For A Multichannel System, Kyong-Hwa Lee

Electrical and Computer Engineering ETDs

This paper is concerned with the problem of obtaining the optimal linear vector coding (transformation) method that matches an r-dimensional vector signal and a k-dimensional channel under a given channel power constraint. the encoder converts the r correlated random variables into r independent random variables and selects at most k independent random variables which correspond to the k largest eigenvalues of the signal covarience matrix Q. The encoder reinserts cross-correlation into the k random variables in such a way that the largest eigenvalue of Q is assigned to the smallest eigenvalue of the channel noise covarience matrix R and the …

Waviness Distortion In Mechanical Face Seals, Joseph J. Roesch

Mechanical Engineering ETDs

In this thesis the phenomenon of waviness distortion in mechanical face seal washers is investigated. Waviness in face seals leads to leakage in some applications. When leakage becomes significant, the seal must be replaced. If the distortion causing mechanism can be described, improvement in seal performance and behavior may be possible.

The components and function of the mechanical face seal are first discussed. It is seen that only one component of the seal unit shows significant deterioration over a period of time. It is also seen that this component, the face washer, wears in a characteristic manner. The characteristics of …

A Prompt D-D Neutron Calibration Of A Plastic Scintillator Detector, Dal H. Jensen

Nuclear Engineering ETDs

ABSTRACT

A new approach to the measurement of the neutron yield of low intensity (~ 2 x 10 neutrons/pulse) 0-0 neutron generators in a single pulse is described. A cylindrical (20.32 cm radius by 20.32 cm height) scin­tillator of Pilot-Bis optically coupled to a Phillips 57AVP photomulti­plier with a 20 cm diameter photocathode. The light pulse resulting from the neutron burst is fed into a voltage integrator calibrated in neutrons/ count.

The initial calibration of the stable neutron generator used in the scintillator calibration was performed using a silver activation detector (PT-502) designed by LASL. The data obtained for the …

Safeguards Considerations For A Htgr Nuclear Fuel Cycle, Philip G. Johnson

Nuclear Engineering ETDs

Given that the prime objective of safeguards for special nuclear materials (SNM) is nonproliferation of nuclear weapons, it is logical that safeguards priorities should be commensurate with the relative suitabilities of the various SNM forms in existence for application in nuclear explosives. The SNM forms in each reactor fuel cycle, for example, should be screened and ordered according to their relative suitabilities for such misapplication. Significant considerations in assigning protection priorities include the relative suitabilities based on materials characteristics, inherent protection features of the mateerials or the processing of the SNM forms, the quantities of these materials in existence, and …

Methods For Calculating Energy Deposition Using Coupled Neutron-Gamma Ray Transport, Lewis Douglas Rigdon

Nuclear Engineering ETDs

In radiation damage problems, it is desirable to know not only the neutron and gamma ray fluxes but also the energy deposition due to those fluxes. Following the recent availability of coupled neutron-gamma ray, multigroup-multitable cross sections and associated fluence-to-KERMA factors, an automated method has been developed for obtaining the energy deposition in a material region due to local neutron and gamma ray fluxes. Cross section sets which combine neutron and photon transport as well as a production matrix for neutron-induced gamma rays are used in the transport calculation. Thus in one discrete ordinates transport calculation, the energy deposition from …

Stresses At The Tips Of Cracks Emanating From The Loaded Fastener Hole, Venkataraman Shivakumar

Mechanical Engineering ETDs

Stress-intensity factors, K, are obtained at the tips of radial cracks emanating from the boundary of an internal circular fastener hole in a plate loaded by a pin or rivet that just fills the hole and is pulled in the negative y-direction, in the plane of the plate. Solutions are obtained in a conformally mapped region in the form of series for different crack lengths and are based on the Muskhelishvili formulation in the two-dimensional theory of elasticity. The method presents a general technique for determining K for k symmetrically located radial cracks of equal length for a wide variety …