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Articles 71611 - 71640 of 196672

Full-Text Articles in Engineering

Modeling Strategies For Estimating And Suppressing Electromagnetic Interference And Improving Power Integrity, Tamar Makharashvili Jan 2019

Modeling Strategies For Estimating And Suppressing Electromagnetic Interference And Improving Power Integrity, Tamar Makharashvili

Doctoral Dissertations

"Decoupling capacitors are used to suppress high-frequency noise in power distribution networks. The inductance associated with a mounted decoupling capacitor can vary by 26% depending on characteristics of the printed circuit board. Here, simple and accurate inductance models of 2- and 8-terminal capacitors including connections to the power and return plane are developed. Circuit models of the capacitors and layout are created using the partial equivalent element circuit method which provide options for circuit-level simulations as well as analytic estimation of inductance. The circuit solution matches results from the full-wave simulation model within 9% for the 8-terminal capacitor and within …


Characterization And Modeling Of Esd Events And Near-Field Scanning Calibration Structures, Shubhankar Kashinath Marathe Jan 2019

Characterization And Modeling Of Esd Events And Near-Field Scanning Calibration Structures, Shubhankar Kashinath Marathe

Doctoral Dissertations

"This research is divided into three papers that cover, two major topics. The first topic, system-level electrostatic discharge (ESD), is discussed over the course of two papers. The second topic, a calibration structure for near-field scanning probe calibration application, is discussed in the last paper. In the first paper, software-assisted detection methods are proposed for secondary ESD discharges. The measured waveforms are analyzed with respect to waveform parameters, such as the vertical threshold of the rising edge, the derivative of the current waveform, and total charge delivered. These parameters enable automatic detection of secondary ESD while monitoring the discharge waveform …


Novel Insights Into Low Salinity Water Flooding Enhanced Oil Recovery In Sandstone Reservoirs, Hasan N. Al-Saedi Jan 2019

Novel Insights Into Low Salinity Water Flooding Enhanced Oil Recovery In Sandstone Reservoirs, Hasan N. Al-Saedi

Doctoral Dissertations

"Ever growing global energy demand and the natural decline in oil production from mature oil fields have been the main incentives to search for methods to increase recovery efficiency for several decades. Water flooding is extensively applied worldwide to improve oil recovery. The recent drop in oil prices has turned the oil industry to the cheapest improved oil recovery (IOR) techniques, such as low salinity (LS) waterflooding. Also, the reduction in reservoir energy and the friendly environmental aspects of low salinity water flooding (LSWF) provide additional incentives for its use. That LS water requires decreasing only the active divalent cations …


Study Of Optical Propulsion Concepts And Techniques For Small-Satellites, Jaykob Neil Maser Jan 2019

Study Of Optical Propulsion Concepts And Techniques For Small-Satellites, Jaykob Neil Maser

Doctoral Dissertations

"The first objective of this research is to manufacture and investigate the characteristics and use of asymmetric, metallic, nanostructures for plasmonic force propulsion, a developing method of nano-/picosatellite thrust generation. This project developed a higher-fidelity model of a recently envisioned small spacecraft propulsion system for precision pointing and proximity control. Plasmonic force propulsion harnesses solar light focused onto plasmon reactive sub-wavelength nanostructures to generate polarized oscillations of electrons on the surface of metallic nanostructures which accelerate and expel nanoparticle propellant via strong optical forces. This research also explores how material selection affects the electromagnetic response of the closely positioned asymmetric …


Biomaterials For Bone Regeneration, Youqu Shen Jan 2019

Biomaterials For Bone Regeneration, Youqu Shen

Doctoral Dissertations

"The purpose of this Ph.D. research is to investigate and improve two classes of hydroxyapatite (HA)-based biomaterials for bone repair: calcium phosphate microspheres and bioactive silicate glass scaffolds. These biomaterials were prepared with modified compositions and microstructures and then were evaluated for bone regeneration.

The open HA microspheres with dense convex surfaces and rough and porous concave surfaces were obtained by sectioning closed hollow HA microspheres. Bone regeneration with the open HA microspheres was greater than with the closed HA microsphere at 12 weeks. Hollow biphasic calcium phosphate (BCP) microspheres have been prepared with different fractions of HA and β-TCP …


The Behavior Of Suas Under Explosive Loading Conditions And Implications For Safe Operating Procedures, Ashok Em Sudhakar Jan 2019

The Behavior Of Suas Under Explosive Loading Conditions And Implications For Safe Operating Procedures, Ashok Em Sudhakar

Doctoral Dissertations

"Drones are increasingly being used for tasks previously unimagined and the beneficial uses are evolving. The United States Congress has envisioned the possible uses of drones for both combating and conveying explosive threats and other harmful and destructive activities. Congress' intent is reflected in new laws (2018) and policies (2019).

All civilian available Small Unmanned Aerial Systems sUASs (Drones), weighing less than 55 pounds, in the current market are not designed for operations in explosive environments. This first of a kind research focuses on further understanding of sUASs response to explosive loading and the public policy implications. This research measured …


Long Period Fiber Grating, Thin Coating Of Graphene And Silver Nanowires, And Corrosion Sensing For Life-Cycle Assessment Of Steel Structures, Chuanrui Guo Jan 2019

Long Period Fiber Grating, Thin Coating Of Graphene And Silver Nanowires, And Corrosion Sensing For Life-Cycle Assessment Of Steel Structures, Chuanrui Guo

Doctoral Dissertations

"This study aims to develop and validate a compact, integrated lab-on-sensor system for simultaneous measurement of strain, temperature and corrosion-induced mass loss in steel structures and concrete reinforcement elements in order to assess their life-cycle performance. The sensing system operates based on the principle of long period fiber gratings (LPFG) that are responsive to both thermal and mechanical deformation, and the change in refractive index of any medium surrounding the optical fiber. To fabricate a LPFG sensor for strain and temperature measurement, a CO2 laser aided fiber grating system was assembled. To enable mass loss measurement, a low pressure …


Disrupting Complex Systems With Emerging Technologies: A Study On United States Airport Operations, Emily J. Grone Jan 2019

Disrupting Complex Systems With Emerging Technologies: A Study On United States Airport Operations, Emily J. Grone

Honors Theses and Capstones

The number of United States domestic commercial flight passengers are growing every year, which means the number of people checking-in, dropping off their bags, and going through TSA within airports is equally growing. With the increasing number of passengers and aging airports, there are several areas of pain points within airports where passengers hit a bottleneck due to the current systems that airports have in place. There are three main areas that we are going to reference. First the check-in process, where customers have to get their tickets, input identification information, and check-in for their flight. Second, baggage-drop off, where …


Unified Probe Launch Pattern Design And Methodology Of Differential Probe Characterization, Han Deng Jan 2019

Unified Probe Launch Pattern Design And Methodology Of Differential Probe Characterization, Han Deng

Masters Theses

"Differential probe is wildly used in the signal integrity area to do the accuracy signal measurement in frequency domain or time domain. Comparing with traditional SMA connector measurement, the probe measurement has several advantages such as the high flexibility and measurement efficiency. Nevertheless, the probe has some disadvantages such as multiple design patterns and the difficulty of fast landing. In this thesis, a unified probe landing pattern is provided to solve the con of probes and a probe testing fixture is designed for characterize probe and extract the probe model.

In the first portion, a unified differential probe launching pattern …


Asphaltene Stability In Crude Oil During Carbon Dioxide Injection And Its Impact On Oil Recovery: A Review, Data Analysis, And Experimental Study, Sherif M. Fakher Jan 2019

Asphaltene Stability In Crude Oil During Carbon Dioxide Injection And Its Impact On Oil Recovery: A Review, Data Analysis, And Experimental Study, Sherif M. Fakher

Masters Theses

"Crude oils are usually associated with many compounds, some of which are favorable and others, which are not. One of the most unfavorable components of crude oil that pose severe operational problems and decreases oil production significantly are asphaltenes. These compounds are solids that are homogenized in the crude oil at room temperature but tend to separate from solution when agitated. They can deposit in the reservoir pores, wellbore, and transportation pipelines thus causing severe operational problems and oil recovery reduction.

Even though researchers have been studying asphaltenes for more than 100 years, there is still an ambiguity concerning asphaltene …


Investigating The Use Of Class C Flyash-Based Geopolymer Cement As A Potential Alternative To Portland Cement To Seal Co₂ Storage Wells, Priyesh Parimal Jani Jan 2019

Investigating The Use Of Class C Flyash-Based Geopolymer Cement As A Potential Alternative To Portland Cement To Seal Co₂ Storage Wells, Priyesh Parimal Jani

Masters Theses

"Capturing emitted carbon dioxide from the source of emission and storing it underground is one effective way to reduce the amount of CO2 in the atmosphere and is called carbon capture and storage (CCS). For the successful CCS project, it is necessary to ensure long term storage of injected CO2 inside these selected reservoirs. Portland cement used to cast wells in these reservoirs degrade in CO2 environment and can create migration path for leakage of CO2. The aim of this study was to provide a comprehensive review about the problem, to propose a new geopolymer …


Routing Algorithm For The Ground Team In Transmission Line Inspection Using Unmanned Aerial Vehicle, Yu Li Jan 2019

Routing Algorithm For The Ground Team In Transmission Line Inspection Using Unmanned Aerial Vehicle, Yu Li

Masters Theses

"With the rapid development of robotics technology, robots are increasingly used to conduct various tasks by utility companies. An unmanned aerial vehicle (UAV) is an efficient robot that can be used to inspect high-voltage transmission lines. UAVs need to stay within a data transmission range from the ground station and periodically land to replace the battery in order to ensure that the power system can support its operation. A routing algorithm must be used in order to guide the motion and deployment of the ground station while using UAV in transmission line inspection. Most existing routing algorithms are dedicated to …


Emi Design Of Flyover Qsfp (Fqsfp) Connector For 56+ Gbps Applications, System Level Modelling Of The Z-Directed Component (Zdc), Pranay Kumar Vuppunutala Jan 2019

Emi Design Of Flyover Qsfp (Fqsfp) Connector For 56+ Gbps Applications, System Level Modelling Of The Z-Directed Component (Zdc), Pranay Kumar Vuppunutala

Masters Theses

"This thesis comprises of two parts. Firstly, the Flyover Quad Small Form Pluggable (FQSFP) approach for 56+ Gbps applications is introduced to overcome the limitations from a large loss on typical QSFP ports with surface mount to Printed Circuit Board (PCB) traces. By replacing the PCB traces to the twinax cables, it is possible to achieve around 7 dB lower insertion loss at 40 GHz for the 12-inch path from the switch IC to connector than that of PCB trace with a low loss substrate. Also, to investigate electromagnetic interference (EMI) aspect of FQSFP approach, a simulation model of FQSFP …


Gel Composition And Brine Concentration Effect On Hydrogel Dehydration Subjected To Uniaxial Compression, Xinrui Zhao Jan 2019

Gel Composition And Brine Concentration Effect On Hydrogel Dehydration Subjected To Uniaxial Compression, Xinrui Zhao

Masters Theses

"Gel treatment is a process that injects the gel into a reservoir to control the conformance and improve the sweep efficiency of injection fluids. At a certain pressure gradient, the gel dehydrates in a reservoir due to mechanical forces. This work evaluates the effects of the gel composition and brine concentration on gel dehydration under uniaxial compression. A sodium acrylate-co-acrylamide based gel cross-linked with N, N'-Methylenebisacrylamide (MBAA) was used for the study. The compression test is performed with a rheometer with a plate-plate geometry. The gel dehydration under pressure was measured to see how gel dehydration would be impacted by …


Breaker Evaluation And Formation Damage Remediation Of Re-Crosslinkable Preformed Particle Gel (Rppg), Enze Zhou Jan 2019

Breaker Evaluation And Formation Damage Remediation Of Re-Crosslinkable Preformed Particle Gel (Rppg), Enze Zhou

Masters Theses

"Re-crosslinkable preformed particle gel (RPPG) is a newly developed preformed particle gel for improving sweep efficiency and oil recovery by blocking or reducing the conductivity of fractures and fracture-like channels or conduits. However, RPPG has the potential to plug the facilities or damage the formation if a treatment is not properly conducted.

This work presents the performance of selected oxidizing breakers on the degradation of RPPG. The influence of a few factors on the degradation process was investigated, including breaker type, breaker concentration, temperature, gel concentration, gel aging time, and gel size. Results indicate that breaker type, concentration, and temperature …


Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker Jan 2019

Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker

Masters Theses

"Monitoring and maintaining civil, space, and aerospace infrastructure is an ongoing critical problem facing our nation. As new complex materials and structures, such as multilayer composites and inflatable habitats, become ubiquitous, performing inspection of their structural integrity becomes even more challenging. Thus, novel nondestructive testing (NDT) methods are needed. Chipless RFID is a relatively new technology that has the potential to address these needs. Chipless RFID tags have the advantage of being wireless and passive, meaning that they do not require a power source or an electronic chip. They can also be used in a variety of sensing applications including …


Less Is More: Beating The Market With Recurrent Reinforcement Learning, Louis Kurt Bernhard Steinmeister Jan 2019

Less Is More: Beating The Market With Recurrent Reinforcement Learning, Louis Kurt Bernhard Steinmeister

Masters Theses

"Multiple recurrent reinforcement learners were implemented to make trading decisions based on real and freely available macro-economic data. The learning algorithm and different reinforcement functions (the Differential Sharpe Ratio, Differential Downside Deviation Ratio and Returns) were revised and the performances were compared while transaction costs were taken into account. (This is important for practical implementations even though many publications ignore this consideration.) It was assumed that the traders make long-short decisions in the S&P500 with complementary 3-month treasury bill investments. Leveraged positions in the S&P500 were disallowed. Notably, the Differential Sharpe Ratio and the Differential Downside Deviation Ratio are risk …


Propagation Of Uncertainty Through Coning, Sculling, And Scrolling Corrections For Inertial Navigation, James Daniel Alan Brouk Jan 2019

Propagation Of Uncertainty Through Coning, Sculling, And Scrolling Corrections For Inertial Navigation, James Daniel Alan Brouk

Masters Theses

"This thesis investigates the propagation of estimation errors through generalized coning, sculling, and scrolling algorithms used in modern day inertial navigation systems, in order to accurately quantify the uncertainty in the estimation of position, velocity, and attitude. The corrections for coning, sculling, and scrolling algorithms have an often unaccounted for effect on documented and empirically derived error statistics for measurements used to predict the uncertainty in a vehicle's position, velocity, and attitude estimates. Through the development of an error analysis for these generalized algorithms, mappings of the measurement and estimation errors through the correction termare generated. Using the developed mappings, …


Performance Investigation Of Surface Modified Ceramic Microfiltration Membranes And The Effects Of Ionic Strength, Choji Bitrus Daches Jan 2019

Performance Investigation Of Surface Modified Ceramic Microfiltration Membranes And The Effects Of Ionic Strength, Choji Bitrus Daches

Masters Theses

"The performance of ceramic membranes surface coated with cysteic acid to improve efficiency and reduce fouling rate was studied under two transmembrane pressure (TMP) and constant crossflow velocity (CFV). The filtration process was done in crossflow mode to allow for extended operation of the membranes. the performance of the membranes were determined in terms of the measured fluxes and on content rejection. Cleaning-in-place (CIP) was done on the membranes to ensure flux recovery after each run. The results showed significant improvement on the performance of the membranes with respect to high permeate fluxes and high oil content rejection (> 99.5%). …


Geophysical Imaging Beneath Lake Chesterfield, Missouri, James Daniell Hayes Jan 2019

Geophysical Imaging Beneath Lake Chesterfield, Missouri, James Daniell Hayes

Masters Theses

"Lake Chesterfield in Wildwood, Missouri, has been leaking since construction of the earth-fill dam was completed in 1986, despite numerous mitigation efforts. The mitigation efforts, including the injection of grouting and the emplacement of clay liners, has not solve the leakage problem.

In the current study, geophysical (subsurface imaging) data was acquired across the drained and dry lake bed and along the base of the earth-fill dam to 1) map variable depth to top of bedrock, 2) determine the variable quality of the bedrock to depths on the order of 80 ft., 3) identify any significant karst features beneath the …


Practical Methods For Source Separation In Emc Measurements, Yuanzhuo Liu Jan 2019

Practical Methods For Source Separation In Emc Measurements, Yuanzhuo Liu

Masters Theses

"Electromagnetic emission is critical in the electronic industry with the rapid growth of the development of the electronic device. To identify the emission from the multipule sources, two methods are proposed in the near field scan and total radiated power measurement respectively.

The first method can be applied in the measurement of the field generated by multiple non-correlated sources. The contribution of each source is determined using a blind source separation (BSS) technique. The measurements are performed using one scanning probe and stationary reference probes, avoiding the need to measure the spatial correlations of the random field. The resolving result …


Changes In Fresh Properties Of Flowable Concrete Induced By Pumping And Composition Of The Lubrication Layer, Alexis Salinas Jan 2019

Changes In Fresh Properties Of Flowable Concrete Induced By Pumping And Composition Of The Lubrication Layer, Alexis Salinas

Masters Theses

"Pumping is an easy method to move concrete while keeping stability. It is worldwide accepted as one of the principal methods for concrete placement, as it accelerates construction. Typically, concrete acceptance in terms of fresh quantitative empirical properties (i.e. slump/slump flow and air content) are performed prior to the pumping process. However, empirical measurements have the drawback that they only measure 1 point. Rheology is better tool to evaluate the behavior of concrete. Pumping is a process that induces considerable shearing in the concrete that can impact its rheological properties. Therefore, the magnitude of these changes in fresh properties depends …


Review And Data Analysis Of Low Salinity Water Effect Through Induced Fine Migration, Dawei Xu Jan 2019

Review And Data Analysis Of Low Salinity Water Effect Through Induced Fine Migration, Dawei Xu

Masters Theses

"Low salinity water flooding (LSWF) is well proved to be an effective EOR technology both in laboratory and field tests, however, the conditions for LSWF to work and EOR mechanism is still debatable. Up till now, many mechanisms have been proposed to explain the incremental oil recovery in sandstone by LSWF, for instance, fine migration, ionic exchange, wettability alteration and pH increase.

In this study, we only focus on low salinity water flooding effect through induced fine migration mechanism. The objective of this study is to conduct a comprehensive analysis using statistical analysis methods and explaining the mechanism of fine …


Projectile Impact Effects On A 50 Psi Plug Type Coal Mine Seal, Bruce Albert Von Niederhäusern Jan 2019

Projectile Impact Effects On A 50 Psi Plug Type Coal Mine Seal, Bruce Albert Von Niederhäusern

Masters Theses

"The current lack of projectile damage criteria for mine seals is assessed to determine if criteria should be developed. Impact experiments were performed on a full-scale 50 psi mine seal to determine failure modes, dynamic stress state, and assess risk to existing operational mine seals. Test projectiles were selected from common underground coal mine items propelled by means of a black powder projectile generator. Projectile velocities attained in testing ranged from approximately 100 to 650 ft/s (30 to 200 m/s). Dynamic strain was measured on the non-impact face to derive the state of stress and estimate failure criteria. Penetration models …


Performance Evaluation Of Bmi Resin System For Thin-Ply Composites, Manoj Kumar Reddy Rangapuram Jan 2019

Performance Evaluation Of Bmi Resin System For Thin-Ply Composites, Manoj Kumar Reddy Rangapuram

Masters Theses

"Composites materials are increasingly being used in aerospace applications over the past few years. The unique properties like high strength to weight ratio, thermal stability, fatigue and corrosion resistance set them apart from the conventional materials. Composite materials are well suited for the applications where weight is the primary concern in the design. Composites structures are vulnerable to mechanical as well as thermal loadings. Transverse micro-cracking and delamination are the most common type of failures in composite materials. The thickness of the ply being used play a key role dictating the properties of the resultant composite structure. As the ply …


Aerosol-Jet Printing And Flash Sintering Of Conformal Conductors On Non-Planar Surfaces, I-Meng Chen Jan 2019

Aerosol-Jet Printing And Flash Sintering Of Conformal Conductors On Non-Planar Surfaces, I-Meng Chen

Masters Theses

”The printed electronics have been broadly applied in our daily lives, many new manufacturing methodologies are studied and investigated. The research here presented the full manufacturing process of printed conductors of aerosol printing and flash sintering techniques on substrates such as planar and non-planar surfaces.

The aerosol printing (AJP) was introduced because of its simplicity in experimental setup and flexibility of printing. It produces less ink waste and consumes less manufacturing cost. Furthermore, it has the direct-write ability to print in any customized patterns or shapes on non-planar surfaces. In this study, the Cu NPs was selected as the functioning …


Estimating Electromagnetic Emissions From A Site Installation With Multiple Racks Of Server Equipment, Ze Sun Jan 2019

Estimating Electromagnetic Emissions From A Site Installation With Multiple Racks Of Server Equipment, Ze Sun

Masters Theses

“There are hundreds, sometimes even thousands, of servers working simultaneously inside a data center. Their radiation can be a problem and cause EMI issues. However, it is not feasible to perform full-wave simulation of these racks because of the large electric size of the model. In this thesis, an algorithm is proposed to predict the emission form rack array. The equivalent dipole source is extracted from EMI measurement data of a single rack and used as the radiation source in the multiple rack model. The coupling between racks cannot be ignored, but through the simulation, it is also found that …


Influence Of Pumping Parameters On The Freeze-Thaw And Scaling Resistance Of Highly Workable Concrete, Alexandra Nicole Wehar Jan 2019

Influence Of Pumping Parameters On The Freeze-Thaw And Scaling Resistance Of Highly Workable Concrete, Alexandra Nicole Wehar

Masters Theses

“Over the past 60 years, pumping concrete has gained popularity due to the economic and technical benefits that typically accompanies it. However, boom configuration and flow rate can adversely affect freeze-thaw and scaling resistance of concrete due to the effects of pressure on the air-void system. Therefore, the objective of this research is to assess the influence of different pumping parameters on the durability of hardened self-consolidating concrete. Self-consolidating, flowable, and conventional concrete mixtures were tested during large scale pumping experiments positioning the pump boom in an “A” and a flat shape as well as using different pumping speeds. In …


Controlled Switching In Kalman Filtering And Iterative Learning Controls, He Li Jan 2019

Controlled Switching In Kalman Filtering And Iterative Learning Controls, He Li

Masters Theses

“Switching is not an uncommon phenomenon in practical systems and processes, for examples, power switches opening and closing, transmissions lifting from low gear to high gear, and air planes crossing different layers in air. Switching can be a disaster to a system since frequent switching between two asymptotically stable subsystems may result in unstable dynamics. On the contrary, switching can be a benefit to a system since controlled switching is sometimes imposed by the designers to achieve desired performance. This encourages the study of system dynamics and performance when undesired switching occurs or controlled switching is imposed. In this research, …


Evaluation Of A Marketing Strategy Based On The Concept Of Virtual Energy Audit, Goutham Kumar Reddy Challa Jan 2019

Evaluation Of A Marketing Strategy Based On The Concept Of Virtual Energy Audit, Goutham Kumar Reddy Challa

Graduate Theses, Dissertations, and Problem Reports (ETD)

With the growing world population and efforts to bring better energy access to the people, energy needs of the world are expected to grow in the coming years. Given the limited availability of non-renewable resources, there has been a mounting consensus among the users and the stakeholders to utilize the available energy in the most efficient way by implementing various methods like use of advanced technologies, source reduction, behavioral changes, etc. Energy efficiency in general is considered as a win-win scenario for all the users and/or stakeholders involved as it not only lowers the base load for power generating companies, …