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Articles 100861 - 100890 of 198086

Full-Text Articles in Engineering

Design And Fabrication Of A System For The Additive Manufacturing Of Transparent Glass, Luke John Gilbert Jan 2016

Design And Fabrication Of A System For The Additive Manufacturing Of Transparent Glass, Luke John Gilbert

Masters Theses

"Despite glass' prevalence in the scientific and engineering community, very little research has been conducted attempting to additively manufacture (AM) glass. Even less research has been done on optically transparent glass. Glass’ material properties make it ineligible for most AM processes if the end result is to be transparent. Even small gas inclusions can cause large amounts of scattering. Additively manufacturing transparent glass brings the advantages found in other AM processes with the added benefit of having optical properties better than those found in polymers. Additively manufacturing glass also allows the optical properties of transparent parts to vary arbitrarily. This …


Multifunctional Wearable Epidermal Device For Physiological Signal Monitoring In Sleep Study, J V M S Avinash Kankipati Jan 2016

Multifunctional Wearable Epidermal Device For Physiological Signal Monitoring In Sleep Study, J V M S Avinash Kankipati

Masters Theses

"Sleep is the essential part of life. Thousands of people are suffering from different kinds sleep disorders. Clinical diagnosing and treating for such disorders are costly, painful and quite sluggish. To reach the demand many commercial products are into the market to encourage home based sleep studies using portable devices. These portable devices are limited in use, cannot be handled easily and quite costly. Advancements in technology miniaturized these portable devices to wearable devices to make them convenient and economical. Elastic, soft and thin silicon membrane with physical properties well matched with that of the epidermis provides conformal and robust …


Material Properties Characterization For Multilayer Pcb And Peec Macromodels For Above Plane Decoupling Capacitors, Xiang Fang Jan 2016

Material Properties Characterization For Multilayer Pcb And Peec Macromodels For Above Plane Decoupling Capacitors, Xiang Fang

Masters Theses

"Accurate frequency-dependent dielectric properties are important for accurate modelling of signal and power integrity problems. And decoupling capacitors perform an important function in the impedance reduction of power distribution systems. Hence, precise dielectric properties and micromodels for decoupling capacitors are the key parts for the signal and power integrity design.

In Section 1, the existing method for extracting dielectric properties from fabricated multilayer printed circuit boards based on the measured electrical property of fabricated transmission lines is introduced and validated using simulations. And the potential errors in the procedure are discussed. After that Djordjevic-Sarkar causal dielectric model for dielectric properties …


Shale Instability Of Deviated Wellbores In Southern Iraqi Fields, Ahmed Ali Shanshool Alsubaih Jan 2016

Shale Instability Of Deviated Wellbores In Southern Iraqi Fields, Ahmed Ali Shanshool Alsubaih

Masters Theses

"Wellbore instability problems are the cause for the majority of nonproductive time in the southern Iraqi fields' developments. The most severe problem in terms of effort and disbursement which is referred to a pipe sticking in Tanuma shale formation. Examining the drilling data revealed that this phenomenon was mostly related to the shear failure of the wellbore. Thus, a geomechanical analysis and drilling parameters/ practice optimization analysis were performed on a field in southern Iraq based on data from 45 deviated wells. The geomechanics analysis predicted the suitable drilling fluid density to prevent onset shear failure by using the Mogi-Coulomb …


Mechanistic Understanding Of Water-Rock Interactions During High-Salinity Water-Flooding Of Carbonate Reservoirs, Pu Han Jan 2016

Mechanistic Understanding Of Water-Rock Interactions During High-Salinity Water-Flooding Of Carbonate Reservoirs, Pu Han

Masters Theses

"Chemically tuned water-flooding provides a relatively cheap method of enhanced oil recovery from carbonate and sandstone reservoirs. Several possible recovery mechanisms such as mineral dissolution, multi-component ion exchange, double-layer expansion, adsorption/desorption from rock surface, reduction in interfacial tension, and fines migration that have been proposed are widely debated. The combination of these processes may result in wettability alteration that increases sweep efficiency of water-flooding. Here, wettability alteration due to water-rock interactions will be examined numerically.

To evaluate the wettability alteration, separation between breakthrough curves of the non-reactive component and the cations based on the chromatographic separation will be used due …


Hybrid Manufacturing Processes For Fusion Welding And Friction Stir Welding Of Aerospace Grade Aluminum Alloys, Megan Alexandra Gegesky Jan 2016

Hybrid Manufacturing Processes For Fusion Welding And Friction Stir Welding Of Aerospace Grade Aluminum Alloys, Megan Alexandra Gegesky

Masters Theses

"Friction stir welding and processing can provide for joints in aerospace grade aluminum alloys that have preferable material properties as compared to fusion welding techniques. Aerospace grade aluminum alloys such as AA2024-T3 and AA7075-T6 are considered non-weldable by traditional fusion welding techniques. Improved mechanical properties over previously used techniques are usually preferable for aerospace applications. Therefore, by combining traditional fusion welding and friction stir processing techniques, it could be plausible to create more difficult geometries in manufactured parts instead of using traditional techniques. While this combination of fusion welding and friction stir processing is not a new technology, its introduction …


A Study On Non-Metallic Inclusions In Foundry Steel Process, Marc Leonard Harris Jan 2016

A Study On Non-Metallic Inclusions In Foundry Steel Process, Marc Leonard Harris

Masters Theses

"The effects of sample area and automated SEM/EDS feature analysis parameters (step size, magnification and threshold) on nonmetallic inclusion characterization results has been investigated and optimized. A post-processing program was developed to automatically determine average inclusion chemistry, total element concentrations within inclusions, and for generating joint ternary diagrams with size visualization for representing nonmetallic inclusion populations. Using these tools the evolution of nonmetallic inclusions was examined for 4320 steel at a participating industrial steel foundry. The steel was sampled throughout electric arc furnace melting through ladle refining to the final casting where an in-mold sampling procedure was developed to procure …


Radiation Noise Source Modeling And Near-Field Coupling Estimation In Rf Interference, Liang Li Jan 2016

Radiation Noise Source Modeling And Near-Field Coupling Estimation In Rf Interference, Liang Li

Masters Theses

"With increasing complexities and shrinking size of modern electronic devices, the near-field RF interference issues are becoming challenging for RF-digital mixed circuit design. Predicting the coupling from digital module to RF antennas and mitigating RF interference is important to the system performance. The ultimate goal of this study is to address the desensitization issues existing in modern electronic devices that have mixed high speed digital-RF circuits, such as cellphone and wearable devices.

In order to estimate the near-field noise coupling from digital module to RF antennas, the noise source is anticipated to be replaced by its equivalent radiation model which …


Study Jitter Amplification Of A Passive Channel And Investigation Of S₂₁ Magnitude Extraction Methodologies Using A Pattern Generator And Oscilloscope, Xinyun Guo Jan 2016

Study Jitter Amplification Of A Passive Channel And Investigation Of S₂₁ Magnitude Extraction Methodologies Using A Pattern Generator And Oscilloscope, Xinyun Guo

Masters Theses

"Recently the clock channel jitter amplification has been observed in several publications. Currently in many high-speed I/O systems, to avoid the cost and the complex clock recovery circuit design, people use traces forwarding clock signal from transmitting IC to receiving IC. When these clock traces are long enough, the amount of attenuation will induce not only inter-symbol-interference (ISI) but also modulate with the input jitter. Eventually it will lead some type of jitter been amplified after the channel. Similarly, the high speed communication channel (data channel) will also face this issue. Since there are no studies on the jitter amplification …


Evaluating Completion Performance For Gas Wells In The Upper And The Lower Montney Formation, Canada, Omar Qasim Mohammed Jan 2016

Evaluating Completion Performance For Gas Wells In The Upper And The Lower Montney Formation, Canada, Omar Qasim Mohammed

Masters Theses

"Identifying the key drivers for success of multiple fractured horizontal wells is not straightforward, especially in unconventional reservoirs like the Montney. Al-Alwani et al. (2015) provided a statistical analysis of Montney completions based on publicly available data. They showed that for the entire well population, cumulative gas recovery per stage, declines as the number of completed stages increase. However, their statistical analysis did not differentiate between completions in the Upper/Middle/Lower Montney, and did not include perforation cluster data.

This work documents the statistical analysis of 296 cased-hole horizontal gas well completions reported in the Upper and the Lower Montney. The …


Managing Risks Of Market Price Uncertainty For A Microgrid Operation, Sriram Raghavan Jan 2016

Managing Risks Of Market Price Uncertainty For A Microgrid Operation, Sriram Raghavan

Masters Theses

"After deregulation of electricity in the United States, the day-ahead and real-time markets allow load serving entities and generation companies to bid and purchase/sell energy under the supervision of the independent system operator (ISO). The electricity market prices are inherently uncertain, and can be highly volatile. The main objective of this thesis is to hedge against the risk from the uncertainty of the market prices when purchasing/selling energy from/to the market. The energy manager can also schedule distributed generators (DGs) and storage of the microgrid to meet the demand, in addition to energy transactions from the market. The risk measure …


Carbon Transfer From Magnesia-Graphite Ladle Refractories To Ultra-Low Carbon Steel, Andrew Arthur Russo Jan 2016

Carbon Transfer From Magnesia-Graphite Ladle Refractories To Ultra-Low Carbon Steel, Andrew Arthur Russo

Masters Theses

"Ultra-low carbon steels are utilized in processes which require maximum ductility. Increases in interstitial carbon lower the ductility of steel; therefore, it is important to examine possible sources of carbon. The refractory ladle lining is one such source. Ladle refractories often contain graphite for its desirable thermal shock and slag corrosion resistance. This graphite is a possible source of carbon increase in ultra-low carbon steels. The goal of this research is to understand and evaluate the mechanisms by which carbon transfers to ultra-low carbon steel from magnesia-graphite ladle refractory.

Laboratory dip tests were performed in a vacuum induction furnace under …


Characterization Of Fracture Initiation In Non-Cylindrical Buckle Folds Using 3d Finite Element Analysis, Eli Jacob Steinbeck Jan 2016

Characterization Of Fracture Initiation In Non-Cylindrical Buckle Folds Using 3d Finite Element Analysis, Eli Jacob Steinbeck

Masters Theses

"The spatial distribution of fracture sets associated with buckle folds has been well documented in field studies. There are difficulties, however, in placing accurate constraints on the timing of the initiation of individual fracture sets during the deformation history of the fold under in-situ conditions. This study investigates specific conditions that give rise to the initiation of various fracture sets in the hinge and limb of a pericline, based on an analysis of the effective stress evolution during the processes of buckling and erosional unloading. A 3D finite element modeling approach is used to simulate the effective stress evolution in …


Engine Sound Simulation And Generation In Driving Simulator, Shuang Wu Jan 2016

Engine Sound Simulation And Generation In Driving Simulator, Shuang Wu

Masters Theses

"Simulating a driving environment that provides engine sound as auditory feedback to the driver is a challenging task due to the complexity of engine sound, a wide range of operating speeds, and repeated sound clicking during playback. This thesis describes a method of engine sound simulation and generation for a driving simulator. By analyzing sample sounds, spectral modeling synthesis was used to decompose the sound samples into deterministic and stochastic components. Then, the modeled deterministic and stochastic signals were employed to resynthesize the sounds. To represent engine sounds not available in the recorded database, sound interpolation was applied to two …


Fluid Flow Through Deformation Band, Huining Zhang Jan 2016

Fluid Flow Through Deformation Band, Huining Zhang

Masters Theses

"Cataclastic deformation bands, which are common in porous sandstone, have the potential to restrict fluid flow. Geological studies have shown that permeability of deformation band shear zones can be one to five orders of magnitude less than for the sandstone host rock. However, recent studies based on simplified analytical estimates have shown that fluid flow in jointed deformation bands may not be retarded since joints play an important role in conducting fluids. In this study, 2 dimensional finite element analysis (FEA) is used to simulate the total discharge flow rate through jointed deformations. Variations of single planar and conjugate jointed …


Exploring Reservoir Connectivity With Production Data: Two New Methods And A New Technique, Ghazwan Faisal Jasim Al-Khmaysawee Jan 2016

Exploring Reservoir Connectivity With Production Data: Two New Methods And A New Technique, Ghazwan Faisal Jasim Al-Khmaysawee

Masters Theses

"This study presents two new, simple methods to explore reservoir connectivity, which has a significant impact on field development strategy. Identifying reservoir connectivity during primary depletion plays an important role in achieving the most cost-effective and highest production possible. It is also very important in future secondary and tertiary oil recovery, particularly when costs dictate a limited number of wells such as those in deepwater environments.

The presented methods are reciprocal-productivity index versus total field material-balance time trend lines and reciprocal-productivity index versus time trend lines. Those two methods are quick, simple, inexpensive, and only need rate and pressure data …


Analysis Of Va Sacramento Medical Center Capacity Using Discrete Event Simulation, Tatiana Alejandra Cardona Jan 2016

Analysis Of Va Sacramento Medical Center Capacity Using Discrete Event Simulation, Tatiana Alejandra Cardona

Masters Theses

"The development of simulation models continues to provide effective solutions to a wide range of problems in healthcare systems. In the research presented within this thesis is the development of a representative and validated discrete event simulation model for the purpose of evaluating additional capacity. The study consists of a detailed exploratory analysis, verification and validation tests of the simulation results, and a thorough design of experiments. The exploratory analysis consisted of developing simulation models that provide similar characteristics found in the data. The design of experiments consisted of generating scenarios of various bed additions in the hospital units of …


Accurate Imepdance Measurement Of O Clip And Near Field Coupling Estimation Using Equivalent Dipole Moment Model, Qiaolei Huang Jan 2016

Accurate Imepdance Measurement Of O Clip And Near Field Coupling Estimation Using Equivalent Dipole Moment Model, Qiaolei Huang

Masters Theses

"As cellphones and electronic devices moves towards higher date rates yet smaller form factor, designer face more electromagnetic interference (EMI) and radio frequency interference (RFI) problems. In order to better guide the early design; designers want to know the exact electrical performance of small components, coupling estimation between components.

In Section 1, a de-embedding method is proposed to measure the impedance of an innovative O-shape spring contact, for frequency up to 30 GHz. The measurements are performed under the same condition when it's actually used in cellphones. De-embedding method will be applied to remove the fixture effects of the measurement …


Bioresponsive Polymer Coating On Nanoparticles, Tunyaboon Laemthong Jan 2016

Bioresponsive Polymer Coating On Nanoparticles, Tunyaboon Laemthong

Masters Theses

"Nanotechnology incorporated with molecular biology became a promising way to treat cancer. The size of nanoparticles enables them to overcome the side effects noticed in cancer treatment like chemotherapy and surgery. Various types and shapes of nanoparticles have been synthesized and used in drug delivery to tumor sites. However, one of problems of using these nanoparticles is the aggregation after injecting them into human body due to flow rate of bloodstream. The coagulation and aggregation will result in clogging blood vessel and lower therapeutic efficacy.

In this thesis, a solution to the aggregation problem was proposed, which is coating biopolymer …


Hidden Markov Model Based Non-Intrusive Load Monitoring Using Active And Reactive Power Consumption, Paulomi Nandy Jan 2016

Hidden Markov Model Based Non-Intrusive Load Monitoring Using Active And Reactive Power Consumption, Paulomi Nandy

Masters Theses

"This work presents a residential appliance disaggregation technique to help achieve the fundamental goal in Non-Intrusive Load Monitoring (NILM) problem i.e. simple breakdown of energy consumption based on the appliance type in a household. The appliances are modeled using Hidden Markov Model by utilizing both their active and reactive power consumption data. The data was recorded by attaching Power Standards Lab PQube measurement device to the appliances. Granularity of the power readings of the disaggregated appliance matches with that of the reading collected for individual device. The accuracy of the model is compared with other models developed using only active …


Event-Sampled Direct Adaptive Neural Network Control Of Uncertain Strict-Feedback System With Application To Quadrotor Unmanned Aerial Vehicle, Nathan Szanto Jan 2016

Event-Sampled Direct Adaptive Neural Network Control Of Uncertain Strict-Feedback System With Application To Quadrotor Unmanned Aerial Vehicle, Nathan Szanto

Masters Theses

"Neural networks (NNs) are utilized in the backstepping approach to design a control input by approximating unknown dynamics of the strict-feedback nonlinear system with event-sampled inputs. The system state vector is assumed to be unknown and an observer is used to estimate the state vector. By using the estimated state vector and backstepping design approach, an event-sampled controller is introduced. As part of the controller design, first, input-to-state-like stability (ISS) for a continuously sampled controller that has been injected with bounded measurement errors is demonstrated and, subsequently, an event-execution control law is derived such that the measurement errors are guaranteed …


Development And Testing Of A Fracture Energy-Based Model Of Explosive Asteroid Deflection, James A. Veerkamp Jan 2016

Development And Testing Of A Fracture Energy-Based Model Of Explosive Asteroid Deflection, James A. Veerkamp

Masters Theses

"While asteroid deflection has been studied for the past half century, efforts have generally been directed towards methods that attempt to minimize disruption of the rock body. In order to widen the base of research, a fracture energy-based model of asteroid fragmentation was developed and applied to both asteroid scale and lab testable scale cases. Modeling of the orbital case suggests the capability to deflect a 100 meter diameter asteroid on a 10 year timescale. The model's predicted energy transfer is then compared to laboratory testing using a ballistic pendulum. The results of this testing suggest that the model as …


Data Analysis For Driving Pattern Identification And Driver's Behavior Modeling In A Freeway Work Zone, Hari Narayanan Vijaya Raghavan Nadathur Jan 2016

Data Analysis For Driving Pattern Identification And Driver's Behavior Modeling In A Freeway Work Zone, Hari Narayanan Vijaya Raghavan Nadathur

Masters Theses

"A variety of methods are used by Departments of Transportation (DOT) for informing drivers about upcoming work zones. One such method is work zone signage configuration. Signage plays an important role in work zones to provide guidance to drivers when conditions on the road vary from normal. Therefore, it is necessary to evaluate the effectiveness of different configurations, by law, before implementation of new signage designs that deviate from the national standards.

The Manual on Uniform Traffic Control Devices (MUTCD) is a compilation of national standards for all traffic control devices, including road markings, highway signs, and traffic signals. In …


Bioactive Poly(Beta-Amino Ester) Biomaterials For Treatment Of Infection And Oxidative Stress, Andrew L. Lakes Jan 2016

Bioactive Poly(Beta-Amino Ester) Biomaterials For Treatment Of Infection And Oxidative Stress, Andrew L. Lakes

Theses and Dissertations--Chemical and Materials Engineering

Polymers have deep roots as drug delivery tools, and are widely used in clinical to private settings. Currently, however, numerous traditional therapies exist which may be improved through use of polymeric biomaterials. Through our work with infectious and oxidative stress disease prevention and treatment, we aimed to develop application driven, enhanced therapies utilizing new classes of polymers synthesized in-house. Applying biodegradable poly(β-amino ester) (PBAE) polymers, covalent-addition of bioactive substrates to these PBAEs avoided certain pitfalls of free-loaded and non-degradable drug delivery systems. Further, through variation of polymer ingredients and conditions, we were able to tune degradation rates, release profiles, cellular …


Synthesis And Characterization Of Antioxidant Conjugated Poly(Βeta-Amino Ester) Micro/Nanogels For The Suppression Of Oxidative Stress, Prachi Gupta Jan 2016

Synthesis And Characterization Of Antioxidant Conjugated Poly(Βeta-Amino Ester) Micro/Nanogels For The Suppression Of Oxidative Stress, Prachi Gupta

Theses and Dissertations--Chemical and Materials Engineering

Oxidative stress is a pathophysiological condition defined by an increased production of reactive oxygen species (ROS), which can result in the growth arrest of cells followed by cell disintegration or necrosis. A number of small molecule antioxidants (e.g. curcumin, quercetin and resveratrol) are capable of directly scavenging ROS, thereby short-circuiting the self-propagating oxidative stress state. However, poor solubility and rapid 1st pass metabolism results in overall low bioavailability and acts as a barrier for its use as a drug to suppress oxidative stress efficiently.

To overcome this limitation, these small molecule antioxidants were covalently conjugated into poly(β-amino ester) (PβAE) …


Improving The Capacity, Durability And Stability Of Lithium-Ion Batteries By Interphase Engineering, Qinglin Zhang Jan 2016

Improving The Capacity, Durability And Stability Of Lithium-Ion Batteries By Interphase Engineering, Qinglin Zhang

Theses and Dissertations--Chemical and Materials Engineering

This dissertation is focus on the study of solid-electrolyte interphases (SEIs) on advanced lithium ion battery (LIB) anodes. The purposes of this dissertation are to a) develop a methodology to study the properties of SEIs; and b) provide guidelines for designing engineered SEIs. The general knowledge gained through this research will be beneficial for the entire battery research community.


Peptide-Functionalized Magnetic Nanoparticles For Cancer Therapy Applications, Anastasia K. Hauser Jan 2016

Peptide-Functionalized Magnetic Nanoparticles For Cancer Therapy Applications, Anastasia K. Hauser

Theses and Dissertations--Chemical and Materials Engineering

Lung cancer is one of the leading causes of cancer deaths in the United States. Radiation and chemotherapy are conventional treatments, but they result in serious side effects and the probability of tumor recurrence remains high. Therefore, there is an increasing need to enhance the efficacy of conventional treatments. Magnetic nanoparticles have been previously studied for a variety of applications such as magnetic resonance imaging contrast agents, anemia treatment, magnetic cell sorting and magnetically mediated hyperthermia (MMH). In this work, dextran coated iron oxide nanoparticles were developed and functionalized with peptides to target the nanoparticles to either the extracellular matrix …


Design Of Highly Stable Low-Density Self-Assembled Monolayers Using Thiol-Yne Click Reaction For The Study Of Protein-Surface Interactions, Leila Safazadeh Haghighi Jan 2016

Design Of Highly Stable Low-Density Self-Assembled Monolayers Using Thiol-Yne Click Reaction For The Study Of Protein-Surface Interactions, Leila Safazadeh Haghighi

Theses and Dissertations--Chemical and Materials Engineering

Protein adsorption on solid surfaces is a common yet complicated phenomenon that is not fully understood. Self-assembled monolayers have been utilized in many studies, as well-defined model systems for studying protein-surface interactions in the atomic level. Various strategies, including the use of single component SAMs[1, 2], combinations of long and short alkanethiolates with methyl- and hydroxyl- terminal groups[3, 4], and using mixtures of alkanethiolates with similar chain length and varying terminal functional group [5] have been used to effectively control the surface wettability and determine the effect of surface composition and wettability on protein adsorption. In this dissertation we report …


Three-Dimensional Microstructural Effects On Multi-Site Fatigue Crack Nucleation Behaviors Of High Strength Aluminum Alloys, Yan Jin Jan 2016

Three-Dimensional Microstructural Effects On Multi-Site Fatigue Crack Nucleation Behaviors Of High Strength Aluminum Alloys, Yan Jin

Theses and Dissertations--Chemical and Materials Engineering

An experimental method was further developed to quantify the anisotropy of multi-site fatigue crack initiation behaviors in high strength Al alloys by four-point bend fatigue testing under stress control. In this method, fatigue crack initiation sites (fatigue weak-links, FWLs) were measured on the sample surface at different cyclic stress levels. The FWL density in an alloy could be best described using a three-parameter Weibull function of stress, though other types of sigmoidal functions might also be used to quantify the relationship between FWL density and stress. The strength distribution of the FWLs was derived from the Weibull function determined by …


Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan Jan 2016

Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan

Theses and Dissertations--Chemical and Materials Engineering

Silicon (Si) has been considered as a promising negative electrode material for lithium ion batteries (LIBs) because of its high theoretical capacity, low discharge voltage, and low cost. However, the utilization of Si electrode has been hampered by problems such as slow ionic transport, large stress/strain generation, and unstable solid electrolyte interphase (SEI). These problems severely influence the performance and cycle life of Si electrodes. In general, ionic conduction determines the rate performance of the electrode, while electron leakage through the SEI causes electrolyte decomposition and, thus, causes capacity loss. The goal of this thesis research is to design Si …