Engineering Commons^™

Mathematical Modeling And Analytical Solutions Of Dissolved Oxygen And Biochemical Oxygen Demand Profiles Under Three-Dimensional, Unsteady-State Conditions, Uing Woong Kim

Dissertations

Mathematical models describing the temporal and spatial distribution of Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD) for both pervious and impervious channel conditions in 3-dimensions have been constructed, and their analytical solutions were obtained. The solutions were implemented through the application of a digital computer, and their results are presented.

It has been found that there are significant differences in terms of DO and BOD distribution with respect to time and space in relatively deep and wide channels, thus necessitating the use of a 3-D, unsteady-state model.

An Investigation Of The Dynamic Response Of The Activated Sludge Process, Tin-Bai Pan

Dissertations

A new mathematical model, derived from first principles of mass balance, is proposed for describing the mass transfer response of an activated sludge aeration tank in terms of a fluidized bed. The operational data to verify the proposed model were taken from an existing conventional wastewater treatment plant and a bench scale pilot plant.

The mass transfer rate, (K_dA_s), was presented by an empirical dimensionless group function as follows:

((K_dA_s)D_p/D_v) = fA_c (uD_p/ν)a ((ν/D_ν)(MLSS))^b

Or

Sh = f(A_c/A_s ) …

Development And Verification Of A Laboratory Model For Use In The Study Of A Continuous Flow Pressurized Activated Sludge Process, Wayne Frederick Nolte

Dissertations

Investigations concerning the responses of domestic wastewater treated at elevated pressures have demonstrated an acceleration in the rate of biological assimilation of the waste material. The literature is not extensive, but presents much conflicting data. There has been a lack of a coherent approach to the investigation of pressure in wastewater treatment. This demonstrates the need for standard testing apparatus and procedures.

A bench scale pressurized activated sludge process was designed and constructed. The apparatus was tested over a broad range of conditions and was found to give reproducible results. Kinetic responses of the pressurized process are presented.

The Use Of Natural Sorbents For The Treatment Of Industrial Sludge Leachate, Mung Shium Jack Sheih

Dissertations

A sorbent treatment process has been developed which uses natural clay soils and fly ashes as sorbents in the treatment of the hazardous contaminants of potential sludge leachate emanating from industrial landfills. Natural sorbents (i.e., vermiculite, illite, kaolinite, zeolite, acidic and basic fly ashes) were evaluated for the removal of specific cations, anions, and organics from leachates generated from three industrial sludges (i.e., calcium fluoride, metal finishing, and petroleum). The laboratory results indicate that, rather than a single sorbent, a combination of acidic and basic sorbents in a layered system is required to reduce for the measurable contaminants present in …

Paper Recycling : Recovery Of Secondary Fibers By Selective Wettability, Gary Keith Welshans

Dissertations

A separation process has been developed which recovers similar paper grades from a mixed stock by selective wettability. This process capitalizes on the various paper additives which are intended to resist water wetting and result in paper flotation. While water can be used to achieve many desirable paper separations, the detention times required are excessive, and therefore, limit any industrial application. Surface-active agents, in low concentrations, can be used advantageously by reducing the detention times for all paper while the structure of the surfactant can be used to selectively recover similar papers over a controlled time period. Detention times have …

Nonlinear Buckling Of Deep Cylindrical Shell Panels With Imperfections, Madhusudan H. Jhaveri

Dissertations

The work presented in this dissertation is devoted to the analysis of nonlinear buckling of thin cylindrical shells with imperfections. The nonlinearity of the problem treated in this dissertation is that associated with large displacements in the linear elastic range. The method used is not restricted by the magnitude of the displacements provided that the strains do not exceed the limit of proportionality.

Thus, based upon the large deflection theory, cylindrical shell panel is investigated for buckling under the action of uniform external pressure. Certain higher order infinitesimal terms which are usually neglected in the shallow shell theories, have been …

An Analysis Of The Passenger Vehicle Interface Of Street Transit Systems With Applications To Design Optimization, Walter H. Kraft

Dissertations

This research analyzes the Passenger Vehicle Interface of the street transit systems and presents applications for design optimization. The Passenger Vehicle Interface (PVI) is defined as the interaction between the passenger and vehicle elements of the street transit system.

Human observer and photographic studies were conducted in 17 cities in the United States and Canada to measure the time for queues of passengers to board various transit vehicles. The data were analyzed by considering seven factors that affect the Passenger Vehicle Interface: Human Factor, Modal Factor, Operating Practices, Operating Policies, Mobility, Climate and Weather, and Other System Elements. Those effects …

Optimal Planning Of Fixed Route Bus Transit Systems : A Systems Approach, Young Lee

Dissertations

A new bus transit planning tool is developed for application in determining operating policies of a fixed-route bus transit system. The objective of the study is to model a bus transit system which functions under time-varying passenger demands and service characteristics.

The two phase transit model developed in this research is intended for use as a mass transit planning tool, to solve transit problems confronting the mass transit planner. The model is used to compute cost differentials in transit system options. These alternatives of expanding, abandoning or modifying service depend upon the service frequency, fleet size and other system attributes …

A Simulation Modeling Approach To Central City Dynamics, Leonard William Schaper Jr.

Dissertations

This dissertation describes a computer simulation model of a central city with emphasis on its application to Newark, New Jersey. The work begins with a review of the Forrester Urban Dynamics Model; the first attempt to simulate the entire system of the city. The objections to this model which have appeared in the literature are discussed, and the model is viewed in the light of other work in the field. A set of guidelines to aid the "second generation" model building effort is developed. The actual construction of a model which attempts to follow these guidelines is described. First, the …