Physical Sciences and Mathematics Commons^™

Convection In The Melt, John Bryant Drake

Doctoral Dissertations

A physical problem involving the melting/freezing of a phase-change material (PCM) is the applied setting of this research. The development of models that couple the partial differential equations for energy transport and fluid motion with phases of differing densities is a primary goal of the research. In Chapter 2, a general framework is developed for the formulation of conservation laws that admit interfaces. A notion of weak solution is developed and its relation with classical and other weak formulations is discussed. Conditions that hold across various kinds of interfaces are also developed. The formulation is examined for the conservation of …

On Some Problems In Analysis Of Covariance Structure., Sadhan Samar Maiti Dr.

Doctoral Theses

In recent years, the teahniques of struotural analynie of covarianoe and correlation matrioes have frequently be en employed espeed ally in the s ooial and behavioural soieno es for analysing multivariate data. Analysis of covarlance structures (ACOVS) lea; generie tem describing a variety of statistioal procedures for testing and measuring the goodnese-of-fit of certain types of struotures postulated a priori for the cova- riance matrix by plaoing al temative restriotione on the para- neter natrioes of the general model" [Mukherjee, 1976, p. 132].The aoronyn AOOVS' standa for; analyeis of covarianoe atructurea; and waa firat proposed by Book (1960) as a …

On Shock Capturing For Liquid And Gas Media, Tze Jang Chen

Mathematics & Statistics Theses & Dissertations

The numerical investigation of shock phenomena in gas or liquid media where a specifying relation for internal energy is absent poses special problems. Classically, for gas dynamics the usual procedure is to employ a splitting scheme to remove the source terms from the Euler equations, then up-wind biased shock capturing algorithms are built around the Riemann problem for the system which remains. However, in the case where the Euler equations are formulated in the term of total enthalpy, a technical difficulty associated with equation splitting forces a pressure time derivative to be treated as a source term. This makes it …

The Solution Of A Singular Integral Equation Arising From A Lifting Surface Theory For Rotating Blades, Mark H. Dunn

Mathematics & Statistics Theses & Dissertations

A technique is presented for the solution of a linear, two dimensional, singular, Volterra integral equation of the first kind. The integral equation, originally developed by Farassat and Myers, is derived from the basic equations of linearized acoustics and models the lifting force experienced by an infinitesimally thin surface moving tangent to itself. As a particular application, the motion of modern high speed aircraft propellers (Advanced Technology Propellers) is considered. The unknown propeller blade surface pressure distribution is approximated by a piecewise constant function and the integral equation is solved numerically by the method of collocation. Certain simplifying assumptions applied …

On The Computation Of Bang-Bang Controls, Carol San Soucie

Honors Theses

No abstract provided.

Numerical Simulation Of Saturated Flow With Fractal Analysis Of The Hydraulic Conductivity Distribution, Joan Leilani Oana

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The purpose of this report is to investigate the behavior of a nonreactive contaminant in a perfectly stratified aquifer under uniform, steady-state flow. The design and the implementation of a solute transport model which characterizes the heterogeneities of the aquifer properties in a stochastic framework is reviewed. The model closely examines the advection and dispersion of the plume. The advection is the process by which the plume is transported in the aquifer by the bulk average motion of the groundwater whereas the dispersion refers to the spreading of the plume about its mean displacement position. The relationship between the fractally …

Linear Operators Strongly Preserving Polynomial Equations Over Antinegative Semirings, Sang-Gu Lee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We characterized the group of linear operators that strongly preserve r-potent matrices over the binary Boolean semiring, nonbinary Boolean semirings, and zero-divisor free antinegative semirings. We extended these results to show that linear operators that strongly preserve r-potent matrices are equivalent to those linear operators that strongly preserve the matrix polynomial equation p(X) = X. where p(X) = X^r₁ + X^r₂ + ... + X^r_t and r₁>r₂>...>r_t≥2.

In addition, we characterized the group of linear operators that strongly preserve r-cyclic matrices over the same semirings. We …

Mathematical Programming Applications In Agroforestry Planning, Laurence H. Reeves

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Agroforestry as a sustainable production system has been recognized as a land use system with the potential to slow encroachment of agriculture onto forested lands in developing countries. However, the acceptance of nontraditional agroforestry systems has been hampered in some areas due to the risk-averse nature of rural agriculturalists. By explicitly recognizing risk in agroforestry planning, a wider acceptance of agroforestry is possible. This thesis consists of a collection of three papers that explore the potential of modern stock portfolio theory to reduce financial risk in agroforestry planning.

The first paper presents a theoretical framework that incorporates modern stock portfolio …

Lcm-Stability Of Power Series Extensions Characterizes Dedekind Domains, John T. Condo

Doctoral Dissertations

In this dissertation, we prove the following main result in Chapter 3. A (communicative integral) domain R is a Dedekind domain if and only if R[[X]] ⊂ T[[X]] is LCM-stable of each domain T containing R as a subring. Analogous results on flatness are given in Chapter 4. Complete statements of results cited from the literature appear in Chapter 2, while Chapter 1 places the above stated main result in historical context, as extending work of F. Richman and H. Uda.

Indifference Graphs And The Single Row Routing Problem, Peter J. Looges

Computer Science Theses & Dissertations

This thesis investigates the subclass of interval graphs known as indifference graphs. New optimal algorithms for recognition, center, diameter, maximum matching, Hamiltonian path and domination in indifference graphs are presented. The recognition algorithm produces a linear order with properties which allow the solution of the other problems in linear time. Indifference graphs are further applied to the single row routing problem which results in both sequential,. and parallel routing algorithms.

Planning And Resource Mobilization In A Developing Economy., Dilip Ratha Dr.

Doctoral Theses

In developing economies, the per capita availability of essential goods and services is quite low. Hence a large section of the society cannot afford even the mininum necessities of 1ite. While human and natural resources are plenty, produced means of produetion like plant and equipment and construction materiais are soaroe. Hence the human resources are not fully utilized. Since the distribution of income and assets is highly skewed, even the snall quantity of essential goods and services is not equitably distributed. When resources 11ke land and capital are privately owned and goods and services are distributed through the narket mechanism, …

On Image Information Measures And Object Extraction., Nikhil Ranjan Pal Dr.

Doctoral Theses

The field of image processing deals with the manipulation of data which are inherently two-dimensional in nature. techniques of image processing sten from two principal application The areas, namely, Improvement of pictorial information for human interpretation and processing of scene data for automatic machine perception. These areas together have experienced a vigorous growth in recent years because they have offered a number of important applications in solving scientific and engineering problems. In biological and medical sciences, we are interested in automatie analysis and interpretation of radiographs, cell images micrographs. In netallurgical, geological and and tissue environmental sciences, we are concerned …

Component Importance In A Consecutive K-Out Of N:F System., Arvind Seth Dr.

Doctoral Theses

Reliability theory has nequired a special significance during the last few decades. It is mainly because of rapid advancement in technology which has given rise to complex and sophisticated systems. These systema suf- fer from derign flawe and wenknesses and their failures not only result in monetary lom but also pose a serious threat to human life and national se curity. Hence product reliability and safety is of paramount importance to us. Since system effectiveness can be optimised during design and develop- ment phases, it therefore calls for a detailed reliability engineering program during initial stanges. Often we find that …

The Impact Of Tourism On Block Island, Thomas Green

Theses and Major Papers

This thesis examines the impacts of tourism on the residents of Block Island. More specifically the study seeks to identify the specific areas of concern, as perceived by the residents, in three major areas of impact: economic, social and environmental. It was hypothesized that the residents of Block Island, a mature tourist destination area, had formulated perceptions of the impacts of tourism and that these perceptions, if analyzed, would identify protection of the environment and threats to the Island's lifestyle as major concerns. Factor analysis was employed to analyze survey responses from residents on questions regarding tourism on Block Island. …

A Study Of The Survival Rate Of The Hepatitis B Virus, James Abraham Houck Iii

UNF Graduate Theses and Dissertations

Hepatitis B virus (HBV) is one of many viruses transmitted through the blood or body fluids. This paper concentrates on a mathematical study of the survival rate of HBV. Using data which includes the survival time for individuals who were diagnosed as being affected by HBV and those who died from HBV, we fit non-linear models to study the survival time for people affected by the virus. Survival probabilities suggest an exponential curve for the survival time. We also consider a pure death process which is a stochastic model for the survival time of the individuals affected. Our results show …

A Comparison Of Ancient Mathematical And Calendrical Systems, Karen Schlauch

Masters Theses

No abstract provided.

Estimation In A Marked Poisson Error Recapture Model Of Software Reliability, Rajan Gupta

Mathematics & Statistics Theses & Dissertations

Nayak's (1988) model for the detection, removal, and recapture of the errors in a computer program is extended to a larger family of models in which the probabilities that the successive programs produce errors are described by the tail probabilities of discrete distribution on the positive integers. Confidence limits are derived for the probability that the final program produces errors. A comparison of the asymptotic variances of parameter estimates given by the error recapture and by the repetitive-run procedure of Nagel, Scholz, and Skrivan (1982) is made to determine which of these procedures efficiently uses the test time.