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Articles 1921 - 1950 of 2584

Full-Text Articles in Engineering

Parametric Amplification In The Context Of Vibratory Energy Harvesting, Roger Bode May 2011

Parametric Amplification In The Context Of Vibratory Energy Harvesting, Roger Bode

All Theses

Using a vibratory energy harvester (VEH) to independently power a sensor has become an increasingly popular topic due to the small amount of power current sensors require to operate. This can be achieved by scavenging energy from the ambient environment where the sensor is located. Numerous linear and nonlinear energy harvesters have been proposed in order to deal with various vibratory environments, along with improving the power production and/or bandwidth of the device.
In this thesis, we propose a technique to harvest energy from excitation sources that possess two frequency components: a fundamental component with large energy content, and a …

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Requirements Determination Of A Novel Non-Pneumatic Wheel Shear Beam For Low Rolling Resistance, Niranjan Thyagaraja May 2011

Requirements Determination Of A Novel Non-Pneumatic Wheel Shear Beam For Low Rolling Resistance, Niranjan Thyagaraja

All Theses

The hysteretic loss associated with cyclic shear in the elastomeric shear layer is one of the prevailing concerns for the development of a low rolling loss non-pneumatic wheel. We propose to eliminate the hysteretic losses associated with the elastomeric shear layer and thus, reduce the corresponding rolling resistance by using linear elastic materials which are inherently non-hysteretic. Since the shear modulus of a viscoelastic shear layer is less than that of an elastic material by several orders of magnitude, the challenge to achieve a low effective shear modulus shear layer with linear elastic materials directs towards the development of a …

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Agent-Based Under Hood Packing, Karthik Ravindranath May 2011

Agent-Based Under Hood Packing, Karthik Ravindranath

All Theses

Improving vehicle performance and passenger comfort has been a prime engineering concern and focus of research for many years in automotive design. Turning to high-performance components in an effort to improve vehicle performance alone is often not enough and their placement and interactions with other components should also be an integral part of the improvement process. With the advancement in hybrid electric vehicle technology, the packing of components under the hood is ever more essential and challenging. Under hood packing is a multi-objective optimization problem with many, and mostly conflicting objectives. A non-deterministic multi-objective evolutionary algorithm needs to be integrated …

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Evaluation Of Biomass And Coal Briquettes For A Spreader Stoker Boiler Using An Experimental Furnace - Modeling And Test, Gavin Wiggins May 2011

Evaluation Of Biomass And Coal Briquettes For A Spreader Stoker Boiler Using An Experimental Furnace - Modeling And Test, Gavin Wiggins

All Theses

The compliance of coal-fired boilers with emissions regulations is a concern for many facilities. The introduction of biomass briquettes in industrial boilers can help to reduce greenhouse gas emissions and coal usage. In this research project, a thermodynamic chemical equilibrium model was derived and analytical simulations performed for a coal boiler system for several types of biomass fuels such as beech, hickory, maple, poplar, white oak, willow, sawdust, torrefied willow, and switchgrass. The biomass emissions were compared to coal and charcoal emissions. The chemical equilibrium analysis numerically estimated the emissions of CO, CO2, NO, NO2, N2O, SO2, and SO3. When …

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Evaluation Of Manganese Control In The Source Water And Microfiltration Plant Of A South Carolina Water Utility, Daniel Lewis May 2011

Evaluation Of Manganese Control In The Source Water And Microfiltration Plant Of A South Carolina Water Utility, Daniel Lewis

All Theses

Although present in most water supplies, manganese is a difficult-to-treat nuisance contaminant in drinking water. The US Environmental Protection Agency (EPA) has set a Secondary Maximum Contaminant Level (SMCL) of 0.05 mg/L but experts have recommended a goal of 0.02 mg/L or less to avoid chronic issues with the metal. This work is a report on manganese control for the Startex-Jackson-Wellford-Duncan (SJWD) Water District, a water utility in northwestern SC. Fourteen locations were sampled from June 2010 through October 2011. Manganese, iron, dissolved organic carbon, dissolved oxygen, and other relevant parameters were measured.
The lake-fed Middle Tyger River is the …

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Implementation Of Delayed-Feedback Controllers On Continuous Systems And Analysis Of Their Response Under Primary Resonance Excitations, Yousef Qaroush May 2011

Implementation Of Delayed-Feedback Controllers On Continuous Systems And Analysis Of Their Response Under Primary Resonance Excitations, Yousef Qaroush

All Dissertations

During the last three decades, a considerable amount of research has been directed toward understanding the influence of time delays on the stability and stabilization
of dynamical systems. From a control perspective, these delays can either have a compounding and destabilizing effect, or can actually improve controllers'
performance. In the latter case, additional time delay is carefully and deliberately introduced into the feedback loop so as to augment inherent system delays and
produce larger damping for smaller control efforts. While delayed-feedback algorithms have been successfully implemented on discrete dynamical systems with
limited degrees of freedom, a critical issue appears in …

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Modeling And Optimization Of Stochastic Process Parameters In Complex Engineering Systems, Paul Goethals May 2011

Modeling And Optimization Of Stochastic Process Parameters In Complex Engineering Systems, Paul Goethals

All Dissertations

For quality engineering researchers and practitioners, a wide number of statistical tools and techniques are available for use in the manufacturing industry. The objective or goal in applying these tools has always been to improve or optimize a product or process in terms of efficiency, production cost, or product quality. While tremendous progress has been made in the design of quality optimization models, there remains a significant gap between existing research and the needs of the industrial community. Contemporary manufacturing processes are inherently more complex - they may involve multiple stages of production or require the assessment of multiple quality …

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Pilot Weather Decision Making And The Influence Of Passenger Pressure, Jaclyn Baron May 2011

Pilot Weather Decision Making And The Influence Of Passenger Pressure, Jaclyn Baron

All Dissertations

The purpose of this study is to determine the effect of social pressure on general aviation (GA) pilots' weather decision making. Data have shown that GA accidents associated with visual flight rules (VFR) flight into instrument meteorological conditions (IMC) are more likely to result in fatalities than other types of GA accidents. This problem is compounded by the addition of passengers, who have been found to be present onboard during VFR into IMC accidents more frequently than in other types of GA accidents. The question is whether passengers influence a pilot's decision to continue flight into adverse weather. The extent …

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Estimating And Mitigating Radiated Emissions From Pcb Heatsinks, Xinbo He May 2011

Estimating And Mitigating Radiated Emissions From Pcb Heatsinks, Xinbo He

All Dissertations

The advance of VLSI technology requires heatsinks to take away the heat generated by ICs and keep the temperature below an acceptable limit. These metal heatsinks radiate and cause EMI problems when electromagnetic noises are coupled to them. Thus it is important to study the possible radiation of a VLSI heatsink and the effective methods to reduce the radiated emissions.
This dissertation includes three chapters on estimating and mitigating VLSI heatsink radiation. In the first chapter, a closed-form expression is derived for determining the maximum possible radiated emissions from a heatsink over a printed circuit board or chassis plane as …

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Methods Development And Force Field Evaluation For Molecular Simulations Of Interactions Between Structured Peptides And Functionalized Material Surfaces, Galen Collier May 2011

Methods Development And Force Field Evaluation For Molecular Simulations Of Interactions Between Structured Peptides And Functionalized Material Surfaces, Galen Collier

All Dissertations

The process of protein adsorption to material surfaces is highly complex and it is one of the most fundamental concepts upon which progress in the field of bioengineering is based. The strategic design of material surfaces for optimal utility in specific biological environments is absolutely dependent upon a thorough understanding of the mechanisms underlying protein adsorption, yet there is still a very limited understanding of these mechanisms. The primary reason for this lack of understanding is that protein adsorption is a dynamic process which occurs at the atomic and macromolecular scale, where experimental analyses provide a view that is static …

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A Methodology For The Analysis Of In-Vehicle Operating Data And Design Of Intelligent Vehicle Systems For Improved Automotive Safety, Matthew Jensen May 2011

A Methodology For The Analysis Of In-Vehicle Operating Data And Design Of Intelligent Vehicle Systems For Improved Automotive Safety, Matthew Jensen

All Dissertations

Every year global motorization increases as more motor vehicles are manufactured, and the total number of vehicle miles traveled rises. These increased travel opportunities result in higher numbers of injuries, fatalities, and monetary losses associated with traffic-related crashes. In the last decade, hundreds of thousands of people were killed by vehicle collisions in the United States. The World Health Organization has labeled traffic crashes as the ninth leading cause of global disease; by the year 2020, traffic crashes are expected to rise to number three. An opportunity exists to improve global human safety through research and innovation in driver training …

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Cellulose Nanocrystals Properties And Applications In Renewable Nanocomposites, Esteban Urena Benavides May 2011

Cellulose Nanocrystals Properties And Applications In Renewable Nanocomposites, Esteban Urena Benavides

All Dissertations

Development of novel bio-based nanocomposites is fundamental to reduce the dependence on fossil resources and provide a sustainable future. In light of this global problem, cellulose nanocrystals (CNCs) have raised interest due to their remarkable mechanical properties. Adequate design of nanocomposites requires a fundamental understanding of how the structure affects the mechanical properties of the material. However, contradictory results in the literature have revealed a lack of comprehension of this relationship for CNC based composites. Consequently, this work provides an explanation to unusual results for CNC nanocomposites presented in the literature and demonstrates the ability to achieve property enhancements in …

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High Resolution Vision-Based Servomechanism Using A Dynamic Target With Application To Cnc Machines, Carlos Montes-Solano May 2011

High Resolution Vision-Based Servomechanism Using A Dynamic Target With Application To Cnc Machines, Carlos Montes-Solano

All Dissertations

This dissertation introduces a novel three dimensional vision-based servomechanism with application to real time position control for manufacturing equipment, such as Computer Numerical Control (CNC) machine tools. The proposed system directly observes the multi-dimensional position of a point on the moving tool relative to a fixed ground, thus bypassing the inaccurate kinematic model normally used to convert axis sensor-readings into an estimate of the tool position.

A charge-coupled device (CCD camera) is used as the position transducer, which directly measures the current position error of the tool referenced to an absolute coordinate system. Due to the direct-sensing nature of the …

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A Decision Support System For Assessing Conveyance Options And Modeling Passenger Flow In Airport Terminals, Ping-Nan Chiang May 2011

A Decision Support System For Assessing Conveyance Options And Modeling Passenger Flow In Airport Terminals, Ping-Nan Chiang

All Dissertations

This dissertation focuses on the use of passenger conveyance systems and modeling passenger flow in airport terminals. The successfully designed airport concourse must perform at a level that meets the needs of its users - the passengers. In this research, we propose a database design methodology that allows key conveyance statistics to be analyzed within specific locations across the airport terminal. Using passenger conveyance observations collected at five North American airports, the database enables airport planners, operators and consultants to assess passenger behavior and conveyance device performance. Results from this section of the research were in direct support of the …

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Micro Feature Enhanced Sinter Bonding Of Metal Injection Molded (Mim) Parts To A Solid Substrate, Thomas Martens May 2011

Micro Feature Enhanced Sinter Bonding Of Metal Injection Molded (Mim) Parts To A Solid Substrate, Thomas Martens

All Dissertations

In metal injection molding (MIM), fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density.
The obstacle to sinter bonding a MIM part to a conventional (solid) substrate lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. It is …

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Investigation Of Techniques For Reducing Unintentional Electromagnetic Emissions From Electronic Circuits And Systems, Ho-Cheol Kwak May 2011

Investigation Of Techniques For Reducing Unintentional Electromagnetic Emissions From Electronic Circuits And Systems, Ho-Cheol Kwak

All Dissertations

This dissertation describes three independent studies related to techniques for reducing unintentional electromagnetic emissions from electronic circuits and systems. The topics covered are: low-inductance multi-layer ceramic capacitor for high frequency circuit board decoupling, the application of imbalance difference model to various circuit board and cable geometries, and balanced cable interface for reducing common-mode currents from power inverter.
The first chapter discusses the importance and the meaning of the connection inductance associated with MLCCs and analyzes the effect of plate orientation in MLCCs. It demonstrates that vertically oriented plates have no more or less inductance than horizontally oriented plates when the …

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Tight Polyhedral Representations Of Discrete Sets Using Projections, Simplices, And Base-2 Expansions, Stephen Henry May 2011

Tight Polyhedral Representations Of Discrete Sets Using Projections, Simplices, And Base-2 Expansions, Stephen Henry

All Dissertations

This research effort focuses on the acquisition of polyhedral outer-approximations to the convex hull of feasible solutions for mixed-integer linear and mixed-integer nonlinear programs. The goal is to produce desirable formulations that have superior size and/or relaxation strength. These two qualities often have great influence on the success of underlying solution strategies, and so it is with these qualities in mind that the work of this dissertation presents three distinct contributions.
The first studies a family of relatively unknown polytopes that enable the linearization of polynomial expressions involving two discrete variables. Projections of higher-dimensional convex hulls are employed to reduce …

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Probablistic Assessment Of Roof Uplift Capacities In Low-Rise Residential Construction, Bagyalakshmi Shanmugam May 2011

Probablistic Assessment Of Roof Uplift Capacities In Low-Rise Residential Construction, Bagyalakshmi Shanmugam

All Dissertations

Post hurricane damage investigations of light frame wood residential structures reveal that roof envelope failure induces considerable damage to the structure and its contents. Roof - to - wall (RTW) connection failures though not as common as roof sheathing failure also cause significant structural and material damage. Considerable changes have been made in the ASCE structural loads standard and International Building code (IBC) after hurricane Andrew in order to prevent RTW connection and sheathing failures. That includes not only a substantial increase in the design wind load in the past two decades but also a strict enforcement of tighter nailing …

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In-Wheel Coupled Suspenison And Drive System For Attitude Control And Vehicle Propulsion, Robert Clippard May 2011

In-Wheel Coupled Suspenison And Drive System For Attitude Control And Vehicle Propulsion, Robert Clippard

All Dissertations

The automotive marketplace is a volatile and dynamic system driven by consumer desires, marketing, fuel prices, technology, and legislation. Recently many of these factors have culminated in a common effort to encourage hybrid and electric vehicle development. The technology for electric vehicles has finally found enough maturity to be implemented into consumer based vehicles from hybrid SUVs to high performance sports cars. This expansion in available propulsion systems and vehicle architectures has spurred research and development into new and novel approaches for propulsion as well as systems to provide increased ride comfort.
This work presents a dual electric motor drive …

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Novel Nanofiber Structures And Advanced Tissue Engineering Applications, Vince Beachley May 2011

Novel Nanofiber Structures And Advanced Tissue Engineering Applications, Vince Beachley

All Dissertations

Extracellular matrix (ECM) nanofibers such as collagen and elastin make up an important component of natural tissues. These structural components serve to impart mechanical strength and provide locations for cell attachment and biomolecule storage. Cells respond to their structural environment in a wide variety of ways beyond physical support, and it has been demonstrated that this environment directly modulates cell behaviors such as, morphology, differentiation, ECM production, attachment, and migration. ECM nanofibers also play an important role as a template for tissue formation during development, remodeling, and regeneration. Nanofiber based tissue engineering strategies aim to mimic the geometry of the …

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In Vitro Validation Of Finite Element Analysis Of Blood Flow In Deformable Models, Ethan Kung, Andrea S. Les, C. Alberto Figueroa, Francisco Medina, Karina Arcaute, Ryan B. Wicker, Michael V. Mcconnell, Charles A. Taylor Mar 2011

In Vitro Validation Of Finite Element Analysis Of Blood Flow In Deformable Models, Ethan Kung, Andrea S. Les, C. Alberto Figueroa, Francisco Medina, Karina Arcaute, Ryan B. Wicker, Michael V. Mcconnell, Charles A. Taylor

Publications

The purpose of this article is to validate numerical simulations of flow and pressure incorporating deformable walls using in vitro flow phantoms under physiological flow and pressure conditions. We constructed two deformable flow phantoms mimicking a normal and a restricted thoracic aorta, and used a Windkessel model at the outlet boundary. We acquired flow and pressure data in the phantom while it operated under physiological conditions. Next, in silico numerical simulations were performed, and velocities, flows, and pressures in the in silico simulations were compared to those measured in the in vitro phantoms. The experimental measurements and simulated results of …

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In Vitro Validation Of Finite-Element Model Of Aaa Hemodynamics Incorporating Realistic Outlet Boundary Conditions, Ethan Kung, Andrea S. Les, Francisco Medina, Ryan B. Wicker, Michael V. Mcconnell, Charles A. Taylor Feb 2011

In Vitro Validation Of Finite-Element Model Of Aaa Hemodynamics Incorporating Realistic Outlet Boundary Conditions, Ethan Kung, Andrea S. Les, Francisco Medina, Ryan B. Wicker, Michael V. Mcconnell, Charles A. Taylor

Publications

The purpose of this study is to validate numerical simulations of flow and pressure in an abdominal aortic aneurysm (AAA) using phase-contrast magnetic resonance imaging (PCMRI) and an in vitro phantom under physiological flow and pressure conditions. We constructed a two-outlet physical flow phantom based on patient imaging data of an AAA and developed a physical Windkessel model to use as outlet boundary conditions. We then acquired PCMRI data in the phantom while it operated under conditions mimicking a resting and a light exercise physiological state. Next, we performed in silico numerical simulations and compared experimentally measured velocities, flows, and …

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Meeting Engineering Program Objectives Through Service Learning Opportunities In Developing Countries, Jeffrey M. Plumblee, Lansford Bell, Leidy E. Klotz Feb 2011

Meeting Engineering Program Objectives Through Service Learning Opportunities In Developing Countries, Jeffrey M. Plumblee, Lansford Bell, Leidy E. Klotz

Publications

The civil engineering profession, in an adaptive reaction to emerging roles for civil engineers, is recognizing the need for new engineers to possess a more robust skill set than just the typical design background. This paper describes the efforts of Clemson Engineers for Developing Countries (CEDC) to fulfill the more nontraditional and often unaddressed “learning outcomes” noted by ASCE’s Civil Engineering Body of Knowledge for the 21st Century as important prerequisites for licensure. The learning outcomes are addressed through ongoing international service learning projects in Cange, Haiti. The paper focuses on the following four outcomes and their fulfillment methods: leadership, …

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Transit System Evaluation Process: From Planning To Realization, K Bartman, Jennifer Ogle, Mashrur Chowdhury, Anne Dunning Jan 2011

Transit System Evaluation Process: From Planning To Realization, K Bartman, Jennifer Ogle, Mashrur Chowdhury, Anne Dunning

Publications

Many frameworks exist to help transit agencies plan, operate, and monitor the performance of transit in rural and urban communities. No framework integrates these three critical business practices into one coherent and flexible framework useful to rural and small-sized cities. The primary objective of this research was to integrate planning, operations, and performance measurement activities into a framework designed to evaluate transit in the context of overall mobility. By combining planning, evaluation, and performance monitoring processes, a succinct framework useful to transit agencies and planners was created. In addition to city entities, colleges and universities operating or contracting transit systems …

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Exploring The Potential Of Inkjet Printing For The Fabrication Of Tissue Test Systems, Vidya Seshadri Jan 2011

Exploring The Potential Of Inkjet Printing For The Fabrication Of Tissue Test Systems, Vidya Seshadri

All Theses

Animal models and two-dimensional assays involved in drug testing, vaccine development and basic scientific discovery are not an accurate representation of the human body; hence there is a need to develop new bench top methodologies which are better suited to yield information about in vivo behavior. There is a paucity of reliable in vitro-derived information regarding the reasons for the cause and progression of diseases. These concerns have lead to the development of three-dimensional systems which can facilitate improved understanding of disease etiology and also can bridge the path to the clinic.
The long term goal, beyond the scope of …

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Biodegradation Kinetics For 1,2-Dichloroethane And Ethylene Dibromide In Anaerobic Enrichment Cultures Grown On Each Compound, Rong Yu Jan 2011

Biodegradation Kinetics For 1,2-Dichloroethane And Ethylene Dibromide In Anaerobic Enrichment Cultures Grown On Each Compound, Rong Yu

All Theses

1,2-Dichloroethane (DCA) and ethylene dibromide (EDB) are among the top 15 chlorinated aliphatic compounds on the Agency for Toxic Substances and Disease Registry's Priority List of Hazardous Substances. Co-contamination of groundwater with EDB and 1,2-DCA resulted mainly from environmental releases of leaded gasoline; these compounds were added as lead scavengers. A microcosm study by Henderson et al. with soil and groundwater from a site contaminated with leaded gasoline demonstrated anaerobic biodegradation of EDB at a higher rate, and to a greater extent, than 1,2-DCA. Both compounds were transformed mainly by dihaloelimination to ethene. The objectives of this study were to …

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Segmentation Of Floors In Corridor Images For Mobile Robot Navigation, Yinxiao Li Jan 2011

Segmentation Of Floors In Corridor Images For Mobile Robot Navigation, Yinxiao Li

All Theses

This thesis presents a novel method of floor segmentation from a single image for mobile robot navigation. In contrast with previous approaches that rely upon homographies, our approach does not require multiple images (either stereo or optical flow). It also does not require the camera to be calibrated, even for lens distortion. The technique combines three visual cues for evaluating the likelihood of horizontal intensity edge line segments belonging to the wall-floor boundary. The combination of these cues yields a robust system that works even in the presence of severe specular reflections, which are common in indoor environments. The nearly …

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Improved Line Outage Detection Using Synchrophasor Measurements, Nick Mahoney Jan 2011

Improved Line Outage Detection Using Synchrophasor Measurements, Nick Mahoney

All Theses

The recent advent of synchronized phasor measurements has allowed a power system to be more readily observable. In fact, when multiple buses are observed, applications that were never before possible become a reality. One such application is the detection of line outages in remote or unobserved parts of the system. Two such methods of line outage detection are examined. First, principal component analysis is used to show that highly accurate line outage detection is possible. Using concepts similar to principal component analysis, a novel line outage detection algorithm is developed. Lastly, the efficacy of the novel line outage detection algorithm …

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Characterizing Liquefaction Potential Of Pleistocene Soil Deposits In The Charleston Area, South Carolina, Tahereh Heidari Jan 2011

Characterizing Liquefaction Potential Of Pleistocene Soil Deposits In The Charleston Area, South Carolina, Tahereh Heidari

All Dissertations

Liquefaction potential of major Pleistocene deposits in the Greater Charleston area, South Carolina is investigated in this dissertation. The data considered to characterize liquefaction potential include field performance information the 1886 Charleston earthquake and the results of many seismic cone penetration tests with pore water measurements (SCPTu). The investigation begins with the Mount Pleasant area, and then expands to the entire Greater Charleston area.
A liquefaction potential map of Mount Pleasant is created through reviewing available first-hand accounts of ground behavior during the 1886 earthquake, analyzing cone penetration test and shear wave velocity data, and correlating the results with geology. …

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Design Decisions Under Risk And Uncertainty, Sravya Thoomu Dec 2010

Design Decisions Under Risk And Uncertainty, Sravya Thoomu

All Theses

In the contemporary world of engineering, engineers strive towards designing reliable and robust artifacts while considering and attempting to control manufacturing costs. In due course they have to deal with some sort of uncertainty. Many aspects of the design are the result of properties that are defined within some tolerances, of measurements that are appropriate, and of circumstances and environmental conditions that are out of their control. This uncertainty was typically handled by using factors of safety, and resulted in designs that may have been overly conservative. Therefore, understanding and handling the uncertainties is critical in improving the design, controlling …

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