Engineering Commons^™

A Bi-Level Programming Approach For The Shipper-Carrier Network Problem, Ya Wang

Dissertations

The Stackelberg game betweenshippers and carriers in an intermodal network is formulated as a bi-levelprogram. In this network, shippers make production, consumption, androuting decisions while carriers make pricing and routing decisions.The oligopolistic carrier pricing and routing problem, which comprisesthe upper level of the bi-level program, is formulated either as a nonlinearconstrained optimization problem or as a variational inequality problem,depending on whether the oligopolistic carriers choose to collude orcompete with each other in their pricing decision. The shippers' decisionbehavior is defined by the spatial price equilibrium principle. Forthe spatial price equilibrium problem, which is the lower level of thebi-level program, a …

Development Of Icejet-Based Surface Processing Technology, Dimitri V. Shishkin

Dissertations

The objective of the proposed work is to acquire knowledge needed for the development and deployment of manufacturing processes utilizing the enormous technological potential of water ice. Material removal by blasting with ice media such as particles, pellets and slugs was investigated. The ice media was accelerated by entrainment in a fluid stream (air, steam, liquid water, supercritical C0₂), impact of rotating blades, fluid expansion, etc. The ice-airjet has to replace sand blasting and the ice-waterjet has to replace the abrasive waterjet. Based on these results, technical approaches for surface processing and machining will be improved. A primary …

Concurrent Evaporating Spray Jets In Dilute Gas-Solid Pipe Flows, Xiaohua Wang

Dissertations

Evaporating spray jets into gas-solids suspensions are encountered in many industrial applications. The rapid evaporation of spray jets has significant effects on the gas-solids mixing near the jet nozzle regions, including non-uniform solids concentration dilution, gas/solids temperature reduction, and gas/solids velocity acceleration. Furthermore, the jet structure is altered by the change of solids loading, jet mass flow rate and initial droplet size distribution. These interactions of gas, solids and evaporating droplets dominate the process efficiency and product quality. There is an urgent need for exploring fundamental mechanisms of the multi-phase interactions with heat and mass transfer as there are few …

Systematic Methods For The Design Of A Class Of Fuzzy Logic Controllers, Saad Y. Yasin

Dissertations

Fuzzy logic control, a relatively new branch of control, can be used effectively whenever conventional control techniques become inapplicable or impractical. Various attempts have been made to create a generalized fuzzy control system and to formulate an analytically based fuzzy control law. In this study, two methods, the left and right parameterization method and the normalized spline-base membership function method, were utilized for formulating analytical fuzzy control laws in important practical control applications. The first model was used to design an idle speed controller, while the second was used to control an inverted control problem. The results of both showed …

Numerical Simulation Of Mechanofusion System For Dry Particle Coating Process, Wenliang Chen

Dissertations

A numerical simulation of the Meclianofusion device for dry particle coating is carried out using Discrete Element Method (DEM) technique. In dry particle coating, tiny sub-micron guest particles are coated onto larger micron sized host particles by using mechanical forces, which the Mechanofusion device provides. It consists of a rotating cylindrical chamber that contains the powder mixture, a stationary inner piece (which has a cylindrical surface at the end), and a fixed scraper blade, which prevents powder from caking against the chamber wall. The simulation studies are performed on two scales: system scale to investigate the particle-particle and particle system …

Application Of Chemical Kinetic Modeling To Improve Design And Performance Criteria For A Practical Incineration System, Charles A. Bass Jr.

Dissertations

In this study, detailed thermo-chemical kinetics with networked ideal reactor model were applied to simulate a practical combustion system -the Secondary Combustion Chamber (SCC) of the Rotary Kiln incineration Simulator (RKIS) at the EPA facility at Research Triangle Park, NC. The networked ideal model was developed using analysis of reactor geometry, temperature profile measurements, and SO₂ tracer data provided by EPA. A computer simulation of the networked model was developed using the CHEMKIN H library. A parallel effort considered the effects of non-ideal mixing on detailed thermo-kinetic, simulations. Specifically, an alternate approach was developed to solve the Partially Stirred …

Seismic Response Of Transformer Bushing Systems And Their Rehabilitation Using Frictional Pendulum System, Selahattin Ersoy

Dissertations

This thesis is concerned with the performance of electric power transformers and their attachments under earthquake loading. It begins with the description of the transformers, attached bushings, and some typical examples of substation failures in earthquake loading. This is followed by the development of finite element model of three different sizes of transformers. Finite element models consist of several thousand degrees of freedom and they are basic to this thesis. Some of the major findings from these models are utilized to derive a simplified model of a portion of a substation, The frictional pendulum system (a base isolation method) is …

On Performance Analysis And Implementation Issues Of Iterative Decoding For Graph Based Codes, Xuefei Wei

Dissertations

There is no doubt that long random-like code has the potential to achieve good performance because of its excellent distance spectrum. However, these codes remain useless in practical applications due to the lack of decoders rendering good performance at an acceptable complexity. The invention of turbo code marks a milestone progress in channel coding theory in that it achieves near Shannon limit performance by using an elegant iterative decoding algorithm. This great success stimulated intensive research oil long compound codes sharing the same decoding mechanism. Among these long codes are low-density parity-check (LDPC) code and product code, which render brilliant …

Experimental And Numerical Study Of Flow Characteristics And Segregation In Flow Enhanced Systems, Gregory James

Dissertations

In the study of granular materials, two major topics of importance are powder flow enhancement mechanisms and the flow characterization. This dissertation is involved with both of these topics. With respect to the powder flow enhancement, this study involves investigation of two types of flow enhancement methods. The first flow enhancement method examined is a novel method called the Magnetically Assisted Powder Flow (MAPF) method. In the MAPF, small magnetic particles and powders are placed in a test hopper. A mesh is placed at the bottom of the hopper to hold the magnetic particles while the powder is discharged through …

On The Data Hiding Theory And Multimedia Content Security Applications, Litao Gang

Dissertations

This dissertation is a comprehensive study of digital steganography for multimedia content protection. With the increasing development of Internet technology, protection and enforcement of multimedia property rights has become a great concern to multimedia authors and distributors. Watermarking technologies provide a possible solution for this problem.

The dissertation first briefly introduces the current watermarking schemes, including their applications in video,, image and audio. Most available embedding schemes are based on direct Spread Sequence (SS) modulation. A small value pseudo random signature sequence is embedded into the host signal and the information is extracted via correlation. The correlation detection problem is …

Inelastic Seismic Behavior Of Stiffening Systems : Multi-Span Simply-Supported (Msss) Bridges, Alireza Yazdani-Motlagh

Dissertations

Stiffening behavior can result from interaction between a structure (base system) and its surrounding environment as in the MSSS bridge soil-structure interaction. In this study, three MSSS bridge cases are parametrically analyzed and their dynamic characteristics and behavior are presented and discussed. Later, for investigating stiffening behavior, a simplified stiffening model is introduced and an extensive parametric study with more than 367,000 analyzed cases is performed. In the parametric study, different stiffening parameters (i.e., stiffness, strength, gap size, and mass), 41 strong motion records, and several damage criteria are considered and effects of the stiffening parameters variations on the dynamic …

Computation And Control Of Flow-Induced Noise Behind A Circular Cylinder Using An Acoustic Analogy Approach, Sirivit Taechajedcadarungsri

Dissertations

The computational aeroacoustics (CAA) research, which focuses on predicting acoustics by means of advanced numerical techniques, has recently gained a great deal of progress. In most applications, the prediction of both the sound source and its far-field propagation is necessary as required by regulations. Recently, powerful computers and reliable algorithms have allowed the prediction of far-field noise through the use of Computational Fluid Dynamics (CFD) data as near-field sound sources. One of the most useful analytical methods, used for the computation of noise, is Lighthill's acoustic analogy. The latter will be used in the present study.

Lighthill's acoustic analogy, combined …

Renegotiation Based Dynamic Bandwidth Allocation For Selfsimilar Vbr Traffic, Zafer Sahinoglu

Dissertations

The provision of QoS to applications traffic depends heavily on how different traffic types are categorized and classified, and how the prioritization of these applications are managed. Bandwidth is the most scarce network resource. Therefore, there is a need for a method or system that distributes an available bandwidth in a network among different applications in such a way that each class or type of traffic receives their constraint QoS requirements.

In this dissertation, a new renegotiation based dynamic resource allocation method for variable bit rate (VBR) traffic is presented. First, pros and cons of available off-line methods that are …

Elementary, Pressure Dependent Model For Combustion Of C1, C2 And Nitrogen Containing Hydrocarbons : Operation Of A Pilot Scale Incinerator And Model Comparison, Chad Sheng

Dissertations

A 140000 BTU/hr pilot scale incinerator has been constructed, tested and run; and an online sampling train capable of taking in situ data has been established. The continuous on-line analytical instruments include a CO analyzer, an NO/NOx analyzer and an 02 analyzer. In addition, two gas chromatographs with flame ionization detector are used to determine CH4, C2H2 + C2H4 and total hydrocarbon concentrations. Typical operating conditions are at an average 02 concentration of 6 - 8 %. The NO concentration ranged from 100 - 200 ppm. Approximately I ppm of CH.4 is also present at steady state operations.

The kinetic …

Development Of An Integrated Photonic Sensor For Monitoring Hazardous Organics, Dianhong Luo

Dissertations

In this study, an integrated photonic sensor has been designed and fabricated for the purpose of monitoring hazardous organics in the environment. The operation of the sensor is based on the principles of the Mach-Zehnder interferometry. The sensor consists of a patterned waveguide structure made of phosphosilicate core and silica cladding. LPCVD processes were developed to produce undoped cladding and doped core silicon dioxide films. Diethylsilane (DES), Trimethylphosphite (TMP) and oxygen were used as the precursors for the deposition process. The effects of the O₂/DES ratio and deposition temperature on the properties Of SiO₂ films were investigated. …

Buckling Of Composite Conical Shells Under Combined Axial Compression, External Pressure, And Bending, Youngjin Chung

Dissertations

Conical shells are extensively used in space crafts, robots, shelters, domes, tanks, and in machinery or devices (e.g. as Belleville washers). Thus, the design of minimum weight, maximum strength, stiffened conical (and cylindrical) shells under combined loads has long been of interest to designers. The objective of this study is to improve the strength of conical shells and reduce the weight of the structure. Buckling of composite conical shells subjected to combined axial loading, external pressure, and bending is investigated using energy and finite element methods. The conical shells have single and multiple layers, different cone angle, length, and radius. …

Arq Protocol For Joint Source And Channel Coding And Its Applications, Bin He

Dissertations

Shannon's separation theorem states that for transmission over noisy channels, approaching channel capacity is possible with the separation of source and channel coding. Practically, the situation is different. Infinite size blocks are needed to achieve this theoretical limit. Also, time-varying channels require a different approach. This leads to many approaches for source and channel coding. This dissertation will address a joint source and channel coding that suits Automatic Repeat Request (ARQ) application and applies it to packet switching networks. Following aspects of the proposed joint source and channel coding approach will be presented:

1. The design of the proposed joint source …

Evolutionary Polymorphic Neural Networks In Chemical Engineering Modeling, Li Gao

Dissertations

Evolutionary Polymorphic Neural Network (EPNN) is a novel approach to modeling chemical, biochemical and physical processes. This approach has its basis in modern artificial intelligence, especially neural networks and evolutionary computing. EPNN can perform networked symbolic regressions for input-output data, while providing information about both the structure and complexity of a process during its own evolution.

In this work three different processes are modeled: 1. A dynamic neutralization process. 2. An aqueous two-phase system. 3. Reduction of a biodegradation model. In all three cases, EPNN shows better or at least equal performances over published data than traditional thermodynamics /transport or …

Integration Of E-Business Strategy For Multi-Lifecycle Production Systems, Yanchun Luo

Dissertations

Internet use has grown exponentially on the last few years becoming a global communication and business resource. Internet-based business, or e-Business will truly affect every sector of the economy in ways that today we can only imagine. The manufacturing sector will be at the forefront of this change. This doctoral dissertation provides a scientific framework and a set of novel decision support tools for evaluating, modeling, and optimizing the overall performance of e-Business integrated multi-lifecycle production systems. The characteristics of this framework include environmental lifecycle study, environmental performance metrics, hyper-network model of integrated e-supply chain networks, fuzzy multi-objective optimization method, …

Saturation Routing For Asynchronous Transfer Mode (Atm) Networks, Jose Luis Ucles

Dissertations

The main objective of this thesis is to show that saturation routing, often in the past considered inefficient, can in fact be a viable approach to use in many important applications and services over an Asynchronous Transfer Mode (ATM) network. For other applications and services, a hybrid approach (one that partially uses saturation routing) is presented. First, the minimum effects of saturation routing are demonstrated by showing that the ratio, defined as f, of routing overhead cells over information cells is small even for large networks. Second, modeling and simulation and M/D/l queuing analysis techniques are used to show that …

High Solid Loading Aqueous Base Metal/Ceramic Feedstock For Injection Molding, Mohammad Behi

Dissertations

Increasing volume fraction of metal powder in feedstock provided lower shrinkage. Reduction of the shrinkage results in better dimensional precision. The rheology of the feedstock material plays an important role to allowing larger volume fractions of the metal powder to be incorporated in the feedstock forinulations. The viscosity of the feedstock inainly depends on the binder viscosity, powder volume fraction and characteristics of metal powder.

Aqueous polysaccharide agar was used as a baseline binder system for this study.The effect of several gel-strengthening additives on 1.5wt% and 2wt% agar gel was evaluated. A new gel-strengthening additive was found to be the …

Modeling And Experimental Validation Of A Single-Feed Semi-Batch Precipitation Process, Ernesto Uehara-Nagamine

Dissertations

Crystallization is a widely practiced unit operation throughout the chemical and pharmaceutical process industries. Despite its widespread application, crystallization still suffers a disproportionate number of process difficulties due to the complexity of the steps involved in the process. In particular, the final characteristics of the product are strongly affected by the mixing conditions during the process. The development of a validated modeling approach would be highly valuable for the successful prediction of the crystal characteristics under differing mixing conditions.

In the present work, the single-feed semi-batch precipitation process of barium sulfate in a stirred tank was experimentally studied and numerically …

Parametric Study Of Heavy Metal Partitioning In A Pilot Scale Incinerator Burning Simulated Municipal Solid Waste, Sukrut S. Thipse

Dissertations

Incineration is a combustion process used to convert toxic waste to benign gases and residue in presence of excess air. The products of the incineration process are bottom ash, fly ash and the flue gas. Most of the metal-based phases formed in incineration are toxic and their emissions need to be strictly controlled. Therefore, behavior of metal species during incineration must be well understood. Such understanding is possible based on the experimental identification of the metal phases formed in the waste combustion and determination of their concentration in various incineration products.

A pilot-scale incinerator of 140,000 Btu/hr capacity was constructed, …

Turbo Space-Time Coded Modulation : Principle And Performance Analysis, Dongzhe Cui

Dissertations

A breakthrough in coding was achieved with the invention of turbo codes. Turbo codes approach Shannon capacity by displaying the properties of long random codes, yet allowing efficient decoding. Coding alone, however, cannot fully address the problem of multipath fading channel. Recent advances in information theory have revolutionized the traditional view of multipath channel as an impairment. New results show that high gains in capacity can be achieved through the use of multiple antennas at the transmitter and the receiver. To take advantage of these new results in information theory, it is necessary to devise methods that allow communication systems …

Low Energy Implantation Of Boron With Decaborane Ions, Maria Angela Albano

Dissertations

The goal of this dissertation was to determine the feasibility of a novel approach to forming ultra shallow p-type junctions (tens of nm.) needed for future generations of Si MOS devices. In the new approach, B dopant atoms are implanted by cluster ions obtained by ionization of decaborane (B₁₀H₁₄)vapor. Each B atom carries only ~9% of the cluster kinetic energy and the B dose per unit charge is 10 times larger than in the case of monomer ion beams. Thus, the problems of spacecharge, limiting the extraction and transport of low energy (< = 1 keV) beams of B⁺ ions, can …

A Conceptual Framework Of Cost/Benefit Justification For Ergonomic Projects To Reduce Musculoskeletal Disorders In The Workplace, Nitipong Boon-Long

Dissertations

A framework for justifying ergonomic projects to the overall cost savings is developed which estimates the extent of musculoskeletal disorders (MSDs) exposures to a specific industry. A cost structure is developed to estimate the investment needed for an ergonomics program and the costs related to MSDs problems including workers' compensation costs, work-related costs, and labor turnover costs. Data was adopted from sources including Bureau of Labor Statistics (BLS), the Healthcare Cost and Utilization Project (HCUP-3), and estimates suggested in OSHA's former Ergonomics Standard. Top fifteen manufacturing industries with the highest MSDs rates were selected to apply the framework. Results showed …

Scheduling Algorithms For High-Speed Switches, Jinhui Li

Dissertations

The virtual output queued (VOQ) switching architecture was adopted for high speed switch implementation owing to its scalability and high throughput. An ideal VOQ algorithm should provide Quality of Service (QoS) with low complexity. However, none of the existing algorithms can meet these requirements.

Several algorithms for VOQ switches are introduced in this dissertation in order to improve upon existing algorithms in terms of implementation or QoS features. Initially, the earliest due date first matching (EDDFM) algorithm, which is stable for both uniform and non-uniform traffic patterns, is proposed. EDDFM has lower probability of cell overdue than other existing maximum …

Fractionation & Segregation Of Suspended Particles Using Acoustic And Flow Fields, Nazhat Aboobaker

Dissertations

The fractionation of particles by size or by density has many applications in a variety of technologies. Decontamination and separation of fine sediments is useful in treating sediments. The application of acoustic standing wave fields for the fractionation and segregation of suspended particles was studied.

The above technology was implemented at the bench scale by building a Plexiglas chamber. Two ultrasound transducers were fixed to opposite sides of the chamber to generate the acoustic standing wave field. The technology was evaluated using silica dioxide (Si02) (1-5 ~tm) and silicon carbide (SiQ (5-20 ~tm) particle suspensions in deionized water. Due to …

2d And 3d Surface Image Processing Algorithms And Their Applications, Jianlin Gao

Dissertations

This doctoral dissertation work aims to develop algorithms for 2D image segmentation application of solar filament disappearance detection, 3D mesh simplification, and 3D image warping in pre-surgery simulation. Filament area detection in solar images is an image segmentation problem. A thresholding and region growing combined method is proposed and applied in this application. Based on the filament area detection results, filament disappearances are reported in real time. The solar images in 1999 are processed with this proposed system and three statistical results of filaments are presented.

3D images can be obtained by passive and active range sensing. An image registration …

An Investigation Of Centrifugal Blood-Cell Separation, Timothy Edward Roche

Dissertations

This dissertation investigated the centrifugal, batch separation of whole blood into subpopulations of red blood cells (erythrocytes) and white blood cells (leukocytes). Separations took place in a custom-built centrifuge (using a seal-less, anti-twisting feed/withdrawal system) containing, a 25-ml capacity separation chamber. The blood separation chamber had dart-shaped geometry in the radial plane and a constant depth in the axial direction. Separation experiments were performed on whole bovine blood at varying hematocrit, centrifuge speed, and batch duration. A small, companion study of whole human blood separation runs also were conducted; they concentrated on batch duration effect and achieved superior separations.

A …