Engineering Commons^™

Development And Analysis Of Non-Delay-Line Constant-Fraction Discriminator Timing Circuits, Including A Fully-Monolithic Cmos Implementation, David Martin Binkley

Doctoral Dissertations

A constant-fraction discriminator (CFD) is a time pick-off circuit providing time derivation that is insensitive to input-signal amplitude and, in some cases, input-signal rise time. CFD time pick-off circuits are useful in Positron Emission Tomography (PET) systems where Bismuth Germanate (BGO)/photomultiplier scintillation detectors detect coincident, 511-keV annihilation gamma rays.

Time walk and noise-induced timing jitter in time pick-off circuits are discussed along with optimal and sub-optimal timing filters designed to minimize timing jitter. Additionally, the effects of scintillation-detector statistics on timing performance are discussed, and Monte Carlo analysis is developed to provide estimated timing and energy spectra for selected detector …

A Photometric Analysis Of Weapon Separation Characteristics, Douglas Paul Yurovich

Masters Theses

This project attempted to implement a unique multi-camera photometric technology into the discipline of weapons separation testing from tactical jet aircraft.

This project was a U.S. Governmental, Department of Defense tasked affair, that utilized assets of the Naval Air Warfare Center Aircraft Division, Naval Air Station, Patuxent River, Maryland.

The methodology employed consisted of a standard lens calibration procedure; an airspace calibration procedure, that defined the zone for the activity of motion, and targeting of the aircraft and specific store.

With filmed flight test data in hand, the data was digitized through a motion sensor and stored as computer files. …

Non-Linear Dynamics Of A Once-Through Steam Generator, Lamartine Nogueira Frutuoso Guimaraes

Doctoral Dissertations

This dissertation presents a new analytical model for the Once-Through Steam Generator (OTSG) which is a component responsible for the primary coolant heat removal and the generation and supply of superheated steam to the turbine of the Pressurized Water Reactor (PWR) manufactured by Babcock & Wilcox (B&W) Co. This new analytical model provides the explanation of the oscillatory phenomenon observed in all PWRs manufactured by B&W that uses the OTSG as part of the steam supply system. It was found that the oscillatory behavior is related to the friction pressure drop caused by the reduction in flow area due to …

Analysis Of A Hypothetical Criticality Accident Involving Damp Low-Enriched Uo2 Powder, Benan Basoglu

Masters Theses

In this work, we report on the development of a computer model for predicting the excursion characteristics of a postulated criticality accident involving a homogeneous mixture of low-enriched UO₂ powder and water contained in a cylindrical blender. The model uses point neutronics coupled with simple lumped-parameter thermal feedback. The reactivity feedback coefficients, reactivity driving force function, and the mean generation time are computed a priori using Criticality Safety Analysis Sequences No.1(CSASlX) and No.2(CSAS25) in the SCALE-IV system. The temperature of the system is calculated using a simple time-dependent energy balance where two extreme conditions for the thermal behavior of …

Design Of Nozzle Contours For The Pwt 16-Ft Transonic Wind Tunnel, William Everett Milam

Masters Theses

The nozzle contours of the Tunnel 16T nozzle were designed in the early 1950's and, for the most part, were calculated by hand. In addition, corrections have been made to the contours through the use of an influence coefficient correction technique in an attempt to remove small flow irregularities. This correction technique is not based on aerodynamic theory, and, as a result the corrected contours are not necessarily aerodynamically correct. A second problem stems from the fact that the application of the nozzle corrections results in nozzle contours that do not change in a monotonic manner. There are some jacks …

A Taylor Weak Statement Finite Element Algorithm For Real-Gas Compressible Navier-Stokes Simulation, James Downing Freels

Doctoral Dissertations

A new finite element numerical computational fluid dynamics (CFD) algorithm has been developed for efficiently solving multi-dimensional real-gas compressible flow problems in generalized coordinates on modern parallel-vector computer systems. The algorithm employs a Taylor extension on the classical Galerkin weak statement formulation, a time-relaxed iteration procedure, and a tensor matrix product based factorization of the linear algebra jacobian under a generalized coordinate transformation. Allowing for a general conservation law system, the algorithm has been exercised for the two-dimensional Euler and the laminar and turbulent forms of the Navier-Stokes equations. Equilibrium real-gas air properties are admitted, and numerical results verify solution …

Development Of A Generalized Quartic Equation Of State For Pure Fluids, Vinod M. Shah

Doctoral Dissertations

A generalized quartic equation of state has been developed for pure simple fluids. It is a four parameter perturbed hard sphere equation of state. The four parameters of the equation of state for any fluid depend only on three properties of the fluid, namely critical temperature, critical volume and the acentric factor. The repulsive contribution to the pressure has been modelled using an mathematical approximation of a hard-sphere equation of state. An empirical equation is used to model the attractive contributions to the pressure. Being a quartic equation of state, it yields four roots when solved. One root of the …

High Angle Of Attack Handling Qualities Rating Scales, Chris A. Hadfield

Masters Theses

Aircraft handling qualities rating scales have traditionally been developed for closed-loop handling tasks at moderate angles-of-attack (AOA). The latest fighter aircraft, using fly-by-wire flight controls and vectored thrust, are capable of sustained maneuvers at very high AOA. A pitch control margin test (Lackey, 1991) was performed using a specially developed rating scale, which evolved as an element of tests investigating controllability at high AOA, progressing through conceptualization, simulation, and eventual flight test. This pitch control margin test is analyzed in this thesis as a case study in the development of handling qualities rating scales to evaluate high AOA flying qualities. …