Engineering Commons^™

Capacitated And Uncapacitated Facilities Locationallocation Problem With Sensitive Prices, Stochastic Demands, And Inventory, Yaser Al-Alawi

Dissertations

This study developed a quantitative model that solves a facility locationallocation (LA) problem that maximizes the net profits generated from expected sales. The model was formulated to take into consideration demand uncertainty, sensitive prices, and existence of inventory for capacitated and uncapacitated facilities. Four new models for the LA problem with stochastic demands and inventory were developed and studied. The four models were combinations of capacitated and uncapacitated facilities and sensitive and insensitive prices.

A new method was proposed for achieving optimality, and an approximation procedure was developed that could find near-optimal solutions for problems that could not be solved …

Heavy Metal Adsorption On Iron Oxide And Iron Oxide-Coated Silica : Macroscopic, Spectroscopic, And Modeling Studies, Ying Xu

Dissertations

To accurately model metal mobility and bioavailability in soils and sediments, systematic sorption studies are needed using representative and well-characterized minerals. Two important surfaces are iron oxide and silica, which are ubiquitous and associated with one another in the environment playing important roles in metal distribution. The objectives of this research are to develop models for predicting speciation and mobility of toxic trace metal ions in groundwater, soils, and sediments when competing ions are present. A model system for soils and sediments, iron oxide-coated silica, was synthesized; the degree of coatings was highly sensitive to the particle size of silica …

Study Of Si/Sio2 Interface Passivation And Sio2 Reliability On Deuterium Implanted Silicon, Tias Kundu

Dissertations

One of the major defects that contribute to the interface states in the silicon band gap is the dangling bond, which degrades performance of MOS devices. Passivation of these bonds with hydrogen had been found to diminish their effect but the improvement degrades the operation due to hot electron effect. Passivation with deuterium annealing has proven to improve the lifetime of the metal oxide semiconductor devices but this technique is not very effective for a multi-level metal-dielectric structure. This work investigates and optimizes incorporation of deuterium by ion implantation into the silicon substrate before the growth of 6.5 nm thin …

Robust Techniques And Applications In Fuzzy Clustering, Amit Banerjee

Dissertations

This dissertation addresses issues central to frizzy classification. The issue of sensitivity to noise and outliers of least squares minimization based clustering techniques, such as Fuzzy c-Means (FCM) and its variants is addressed. In this work, two novel and robust clustering schemes are presented and analyzed in detail. They approach the problem of robustness from different perspectives. The first scheme scales down the FCM memberships of data points based on the distance of the points from the cluster centers. Scaling done on outliers reduces their membership in true clusters. This scheme, known as the Mega-clustering, defines a conceptual mega-cluster which …

Variable Permittivity Dielectric Material Loaded Stepped-Horn Antenna, Ozgur Ozdemir

Dissertations

Stepped-horn antenna loaded with dielectric material of variable permittivity is proposed to improve radiation characteristics and/or to increase the electrical dimensions of the radiating structure compared to unloaded empty one. A hybrid numerical technique is used to analyze such an antenna. The tapered section of the horn antenna is modeled by multi-stepped waveguide structures filled with variable dielectric constant material. Generalized scattering matrix representation of the tapered section of the horn antenna is obtained using mode matching technique. The radiating aperture problem is solved by the method of moments, under the assumption that the horn is terminated by an infinite …

On The Design For Flexibility Of Manufacturing Systems : A Stochiastic Approach, Nathapol Areeratchakul

Dissertations

Flexibility has emerged as one of the most strategic imperatives for company viability in today's fast paced economy. This realization has stimulated extensive research efforts in this area most of which have focused mainly on defining flexibility and its attributes, the need for flexibility and how to measure it. Nevertheless, despite the considerable amount of publications regarding flexibility and its related subjects, insufficient attention has been given to the optimality of the design for flexibility and the inherent needs to meet uncertainty. Bridging this gap is the intent of this work.

In this dissertation, developed analytical models are for the …

Opportunistic Transmission Scheduling For Next Generation Wireless Communication Systems With Multimedia Services, Chengzhou Li

Dissertations

The explosive growth of the Internet and the continued dramatic increase for all wireless services are fueling the demand for increased capacity, data rates, and support of different quality of service (QoS) requirements for different classes of services. Since in the current and future wireless communication infrastructures, the performances of the various services are strongly correlated, as the resources are shared among them, dynamic resource allocation methods should be employed. With the demand for high data rate and support of multiple QoS, the transmission scheduling plays a key role in the efficient resource allocation process in wireless systems. The fundamental …

Energy Efficient Organization And Modeling Of Wireless Sensor Networks, Jin Zhu

Dissertations

With their focus on applications requiring tight coupling with the physical world, as opposed to the personal communication focus of conventional wireless networks, wireless sensor networks pose significantly different design, implementation and deployment challenges. Wireless sensor networks can be used for environmental parameter monitoring, boundary surveillance, target detection and classification, and the facilitation of the decision making process. Multiple sensors provide better monitoring capabilities about parameters that present both spatial and temporal variances, and can deliver valuable inferences about the physical world to the end user.

In this dissertation, the problem of the energy efficient organization and modeling of dynamic …

Optimal Speed Limit For Shared-Use Roadways, Yongqiang Yang

Dissertations

Motor vehicle crashes are a serious social problem in the United States. Each year a large number of motor vehicle crashes occur and many people are killed or injured, resulting in substantial economic costs. To minimize economic costs, it is necessary to determine optimal speed limits on roadways because of the strong relationship among posted speed limit, crash frequency, and crash injury severity.

A comprehensive literature review about the relationship among posted speed limit, crash frequency, and crash injury severity level was conducted. Crash frequency prediction models and crash injury severity models are developed to obtain crash frequency and injury …

Stabilization Of Curtain Coater At High Speeds, Peeyush Tripathi

Dissertations

High-speed curtain coating is an emerging technology trying to gain commercial acceptance by the paper industry as a pre-metered and non-impact coating process. Curtain coating could offer enormous economic and process advantages over conventional coating methods due to non-impact and excellent coverageat reduced coat weights. Due to non-impact and non-contact type of coating operation, curtain coating can operate with fewer sheet breaks or the strength requirements of the base sheet can be greatly reduced. High speed curtain coating for commodity coated grades like LWC is still a challenge. Relationship between various process, basesheet and coating variables and their mechanism must …

Load Interaction Effects On Fatigue Crack Growth, Stoyan Ivanov Stoychev

Dissertations

Load excursions, in the form of tensile and compressive overloads are known to produce interaction effects during subsequent constant amplitude loading. In this work, the fatigue crack growth and crack closure levels, under both constant amplitude and variable amplitude loading, are investigated in the aluminium-lithium alloy 2090-T84, and the aluminium alloys 2024-T351 and 7150-T651. The crack closure measurements were obtained using both a crack tip opening displacement (CTOD) gauge and a crack mouth opening displacement (CMOD) gauge.

Fatigue crack growth tests were performed on specimens of thickness 1.6mm, 3mm, 6mm and 14mm. Tests were performed at load ratios of 0.1 …

Optimization Of Sequential Purification Of Beta-Glucosidase From Tricoderma Reesei In Aqueous Two-Phase System, Shalini Gautam

Dissertations

A novel sequential technique was developed for the purification of a valuable enzyme, beta-glucosidase, from microorganism Tricoderma reesei. The fungus T. reesei produces cellulose degrading enzymes, called cellulases: beta-glucosidase, endo-glucanase and exo-glucanase and low molecular weight proteins. For specific applications, the enzyme must be separated from other contaminants. The sequential technique, that included affinity precipitation with chitosan followed by separation with an aqueous two-phase system (ATPS), was implemented for the purification of beta-glucosidase from the culture filtrate of T. reesei.

The cultivation medium (nutrient) was optimized for the production of betaglucosidase from T. reesei cell culture. Treatment of the …

Nanostructured Composite Materials Based On Carbon Nanotubes And 3-D Photonic Crystals, Jing Chen

Dissertations

Carbon nanotubes (CNT) and in particular, single-wall carbon nanotubes (SWCNT) have been extensively studied, in large part, due to their unique one-dimensional crystalline structures and related electronic and optical properties. Various polymeric composite materials, which were based on carbon nanotubes, have been also developed in an attempt to combine the properties of polymer and CNT in a single film. Such composites were mainly formed by mixing carbon nanotubes within the polymer without special emphasis on the structure and thereby, the nanoscopic properties of the resultant material.

Photonic crystals belong to a class of man-made structures aimed at manipulating the propagation …

Communications Over Fading Channels With Partial Channel Information : Performance And Design Criteria, Xinmin Deng

Dissertations

The effects of system parameters upon the performance are quantified under the assumption that some statistical information of the wireless fading channels is available. These results are useful in determining the optimal design of system parameters. Suboptimal receivers are designed for systems that are constrained in terms of implementation complexity.

The achievable rates are investigated for a wireless communication system when neither the transmitter nor the receiver has prior knowledge of the channel state information (CSI). Quantitative results are provided for independent and identically distributed (i.i.d.) Gaussian signals. A simple, low-duty-cycle signaling scheme is proposed to improve the information rates …

Development Of Adsorption Filtration Process For Virus Removal For Drinking Water Treatment, Vishal Vijay Gawarikar

Dissertations

Recent monitoring studies have indicated that many ground water (GW) sources would benefit from the development of effective technologies for removing viruses. Although reverse osmosis can achieve high log removal it is not economical. The main objective of this study is to test and validate a novel adsorption filtration (AF) technology for removing viruses from GW sources for drinking water production in New Jersey.

The convective diffusion of viruses to adsorbent particle surfaces in flow packed beds (FPB) enhances their removal efficiency if the adsorbent particle size can be decreased to about 100 microns. The development of effective virus removal …

Mechanics Of Biocell Landfill Settlements, Chamil Hiroshan Hettiarachchi

Dissertations

Prediction of landfill gas generation and settlements are of concerns in design and maintenance of biocell landfills. Accurate settlement prediction is essential for design of piping systems used for the delivery of re-circulated leachate and recovery of landfill gas. Landfill settlement is the result of change in overburden stresses and biodegradation of waste. Biodegradation-induced settlement results from the re-arrangement of waste skeleton in response to the decomposition of waste mass.

Current practice of landfill settlement modeling is predominantly empirical, thus most of the available techniques make no attempt to simulate the real mechanisms of waste settlement. Traditionally compressibility index is …

Evaporating Cross Flow Spray Jets In Gas-Solid Circulating Fluidized Bed, Tong Hoon Lee

Dissertations

Three-phase flow of solid-gas suspension with liquid spray is found in many industrial applications, including fluidized catalytic cracking in petroleum refinery process, and wet scrubbing process. This dissertation study is aimed to understand the gas-solid-liquid three-phase flow structure, phase interactions and transport in a gas-solid circulating fluidized bed where an evaporating cross-flow liquid spray jet from a rectangular nozzle with a fan angle is injected. The investigation is based on both numerical and experimental approaches. The numerical study is for detailed field descriptions of the flow structure, phase interaction and distributions whereas the experimental study is for simulation validations. The …

Fluid-Phase Thermodynamics From Molecular-Level Properties And Interactions Based In Quantum Theory, Steven G. Arturo

Dissertations

A methodology to predict the thermodynamics of macroscopic fluid systems from quantum chemistry and statistical thermodynamics has been developed. This work extends the group-contribution concepts most utilized in chemical engineering. Computational chemistry software is used to define the geometries and electron density profiles of target molecules. Atoms in Molecules theory and associated software packages are used to calculate rigorous properties of the functional groups within molecules of interest. These properties are incorporated into an intermolecular potential energy function which describes interactions between entire molecules as a set of interactions between functional groups. This information is applied to a lattice-fluid model …

Direct Numerical Simulations And Experimental Investigation Of Dielectrophoresis, Arun Thankamony John-Kadaksham

Dissertations

This dissertation deals with the numerical and experimental studies of the phenomenon of dielectrophoresis, i.e., the motion of neutral particles in nonuniform electric fields. Dielectrophoresis is the translatory motion of neutral particles suspended in a dielectric medium when they are subjected to an external nonuniform electric field. The translatory motion occurs because a force called the dielectrophoretic force, which depends on the spatial variation of the electric field, acts on the particles. As the generation of force involves no moving parts and the particles can be moved without touching them, dielectrophoresis can be used in many applications, including manipulation and …

Analysis And Characterization Of The Integrated Dielectric Slab Waveguide-Wedge Antenna Using Iterative Mode-Matching Technique, Chairat Pinthong

Dissertations

A rigorous solution for the TB and TM polarization to the dielectric wedge antenna fed by a slab waveguide of the same material is presented. The method of solution involves modeling the wedge as a sequence of step discontinuities and using an iterative procedure to track forward and backward partial wave fields, expressed as modal expansions, to obtain the rigorous field solution. Radiation patterns of directive gain are presented. All patterns smoothly decrease from a maximum in the endfire direction and exhibit very low side lobes. Longer length wedges are shown to produce higher directivity and smaller half-power beamwidths (HPBW). …

Virtual Transshipments And Revenue-Sharing Contracts In Supply Chain Management, Zhaoqiong Qin

Dissertations

This dissertation presents the use of virtual transshipments and revenue-sharing contracts for inventory control in a small scale supply chain. The main objective is to maximize the total profit in a centralized supply chain or maximize the supply chain's profit while keeping the individual components' incentives in a decentralized supply chain.

First, a centralized supply chain with two capacitated manufacturing plants situated in two distinct geographical regions is considered. Normally, demand in each region is mostly satisfied by the local plant. However, if the local plant is understocked while the remote one is overstocked, some of the newly generated demand …

Simulation Of Creep In Nickel Based Single Crystal Superalloys, Yunhong Pang

Dissertations

Nickel based single crystal Superalloys are finding wide spread use in high temperature gas turbines and other similar applications because of their superior high-temperature strength and creep properties as compared to the other materials. This is due to two factors: solid solution and precipitation strengthening of the gamma (γ) and gamma prime (γ') phases, and the elimination of grain boundaries. Creep of Nickel based single crystal Superalloys are caused by two primary mechanisms, dislocation creep and diffusion creep. Several factors that affect the creep life of Nickel based single crystal Superalloys are the specific microstructure, stress, temperature and rafting. Also, …

Security Information Management With Frame-Based Attack Presentation And First-Order Reasoning, Wei Yan

Dissertations

Internet has grown by several orders of magnitude in recent years, and this growth has escalated the importance of computer security. Intrusion Detection System (IDS) is used to protect computer networks. However, the overwhelming flow of log data generated by IDS hamper security administrators from uncovering new insights and hidden attack scenarios. Security Information Management (SIM) is a new growing area of interest for intrusion detection. The research work in this dissertation explores the semantics of attack behaviors and designs Frame-based Attack Representation and First-order logic Automatic Reasoning (FAR-FAR) using linguistics and First-order Logic (FOL) based approaches. Techniques based on …

Transceiver Design And System Optimization For Ultra-Wideband Communications, Hongshan Sheng

Dissertations

This dissertation investigates the potential promises and proposes possible solutions to the challenges of designing transceivers and optimizing system parameters in ultra-wideband (UWB) systems. The goal is to provide guidelines for UWB transceiver implementations under constraints by regulation, existing interference, and channel estimation.

New UWB pulse shapes are invented that satisfy the Federal Communications Commission spectral mask. Parameters are designed to possibly implement the proposed pulses. A link budget is quantified based on an accurate frequency-dependent path loss calculation to account for variations across the ultra-wide bandwidth of the signal.

Achievable information rates are quantified as a function of transmission …

Quality-Of-Service Provisioning In High Speed Networks : Routing Perspectives, Gang Cheng

Dissertations

The continuous growth in both commercial and public network traffic with various quality-of-service (QoS) requirements is calling for better service than the current Internet's best effort mechanism. One of the challenging issues is to select feasible paths that satisfy the different requirements of various applications. This problem is known as QoS routing. In general, two issues are related to QoS routing: state distribution and routing strategy. Routing strategy is used to find a feasible path that meets the QoS requirements. State distribution addresses the issue of exchanging the state information throughout the network, and can be further divided into two …

Tcp Performance Enhancement In Wireless Networks Via Adaptive Congestion Control And Active Queue Management, Kai Xu

Dissertations

The transmission control protocol (TCP) exhibits poor performance when used in error-prone wireless networks. Remedy to this problem has been an active research area. However, a widely accepted and adopted solution is yet to emerge. Difficulties of an acceptable solution lie in the areas of compatibility, scalability, computational complexity and the involvement of intermediate routers and switches.

This dissertation rexriews the current start-of-the-art solutions to TCP performance enhancement, and pursues an end-to-end solution framework to the problem. The most noticeable cause of the performance degradation of TCP in wireless networks is the higher packet loss rate as compared to that …

Gas Fluidization Of Nanoparticles, Qun Yu

Dissertations

The primary objective of this study is to perform a systematic investigation on the gas fluidization of various nanoparticle agglomerates. Firstly, the gas fluidization characteristics and regime classifications without any additional external force fields are identified using both experimental measurements and modeling. Secondly, the effect of introducing certain external force fields on nanoparticle fluidization is experimentally investigated. Two external force fields were applied: sound waves from a loud speaker (acoustic assistance) and in-bed magnets that were excited by an external oscillating magnetic field (magnetic assistance). Thirdly, exploratory experimental research on the use of nanoparticle agglomerates as a granular filtration media …

On Rate Capacity And Signature Sequence Adaptation In Downlink Of Mc-Cdma System, Jianming Zhu

Dissertations

This dissertation addresses two topics in the MC-CDMA system: rate capacity and adaptation of users' signature sequences. Both of them are studied for the downlink communication scenario with multi-code scheme.

The purpose of studying rate capacity is to understand the potential of applying MC-CDMA technique for high speed wireless data communications. It is shown that, to maintain high speed data transmission with multi-code scheme, each mobile should cooperatively decode its desired user's encoded data symbols which are spread with different signature sequences simultaneously. Higher data rate can be achieved by implementing dirty paper coding (DPC) to cooperatively encode all users' …

A Versatile Programming Model For Dynamic Task Scheduling On Cluster Computers, Dejiang Jin

Dissertations

This dissertation studies the development of application programs for parallel and distributed computer systems, especially PC clusters. A methodology is proposed to increase the efficiency of code development, the productivity of programmers and enhance performance of executing the developed programs on PC clusters while facilitating improvement of scalability and code portability of these programs. A new programming model, named the Super-Programming Model (SPM), is created. Programs are developed assuming an instruction set architecture comprised of SuperInstructions (SIs). SPM models the target system as a large Virtual Machine (VM); VM contains functional units which are underlain with sub-computer systems and SIs …

Characterization Of Mismatch Between Behavioral Stimuli And Frmi Data Using The Kalman Filter, Jason Steffener

Dissertations

The advance of blood oxygen level dependent function magnetic resonance imaging, (BOLD fMRI), allows researchers to non-invasively investigate the functioning human brain. The BOLD fMRI response to brief stimuli is called the hemodynamic response function (HRF), which can vary across brain regions and across subjects.

Models of the HRF are used to increase sensitivity of statistical maps; however, they often don't account for spatial and temporal variance. Physiological effects, such as learning, fatigue or habituation, introduce mismatch between statistical models and the data. Methods that use minimal a priori information and track time varying signals are able to show the …