Engineering Commons^™

Analysis Of Metallic Shielding For Reduction Of Rf Induced Heating Of Electrode During Mri For Active Implants, Krishna M. Singhal

Open Access Dissertations

The options available to patients with implantable devices are limited. It is because there are multiple interactions between the MRI environment and the implantable medical devices. The three main components of MRI systems- static magnet, RF coil, and a gradient coil- interact with the implantable medical devices. These interactions can cause force, torque, device vibrations and RF-induced heating. Among all these potential hazards is the heating caused by the RF electromagnetic field. The lead wires of the implants can act as antennas and pick up the electric field generated by the RF coil. This results in the induced current traveling …

Santa Clara Magazine, Volume 59 Number 2, 3, 4, August 2018 [Print Issues V. 58:2, 3, 4], Santa Clara University

Santa Clara Magazine

3 - GOOOAL! By Giannina Ong ’18

4 - LOVE, ARMAND Letters from a freshman to his widowed mother from a century ago

Measuring The Vortex-Shedding Frequency Behind Staggered Cylinders In Cross-Flow, Christopher Clark

Mechanical Engineering Master's Theses

In this thesis, the Strouhal numbers from the downstream cylinder in a two cylinder configuration have been measured experimentally. Special apparatuses were designed to secure the cylinders in the wind tunnel as well as to hold a hot film anemometer probe in the center of the downstream cylinder’s wake. The cylinders were smooth, of equal diameter and extended the entire width of the wind tunnel. Because the cylinders used in this thesis were sufficiently long compared to their diameters and measurements were taken at center span, they were assumed to be infinite. The anemometer was calibrated according to King’s Law, …

Evaluation Of Seismic Performance Of Mid-Rise Reinforced Concrete Frames Subjected To Far-Field And Near-Field Ground Motions, Mokhtar Ansari, Masoud Ansari, Amir Safiey

Publications

Damages to buildings affected by a near-fault strong ground motion are largely attributed to the vertical component of the earthquake resulting in column failures, which could lead to disproportionate building catastrophic collapse in a progressive fashion. Recently, considerable interests are awakening to study effects of earthquake vertical components on structural responses. In this study, detailed modeling and time-history analyses of a 12-story code-conforming reinforced concrete moment frame building carrying the gravity loads, and exposed to once only the horizontal component of, and second time simultaneously the horizontal and vertical components of an ensemble of far-field and near-field earthquakes are conducted. …

Mechanically Assisted Electrochemical Degradation Of Alumina-Tic Composites, Hetal Umesh Maharaja, Guigen Zhang

Publications

Alumina-TiC composite material is a tough ceramic composite with excellent hardness, wear resistance and oxidation resistance in dry and high-temperature conditions. In aqueous conditions, however, it is likely to be electrochemically active facilitating charge transfer processes due to the conductive nature of TiC. For application as an orthopedic biomaterial, it is crucial to assess the electrochemical behavior of this composite, especially under a combined mechanical and electrochemical environment. In this study, we examined the mechanically assisted electrochemical performance of alumina-TiC composite in an aqueous environment. The spontaneous electrochemical response to brushing abrasion was measured. Changes in the magnitude of electrochemical …

Exploring The Relationship Between Online Discourse And Commitment In Twitter Professional Learning Communities, Wanli Xing, Fei Gao

Visual Communications and Technology Education Faculty Publications

Educators show great interest in participating in social-media communities, such as Twitter, to support their professional development and learning. The majority of the research into Twitter-based professional learning communities has investigated why educators choose to use Twitter for professional development and learning and what they actually do in these communities. However, few studies have examined why certain community members remain committed and others gradually drop out. To fill this gap in the research, this study investigated how some key features of online discourse influenced the continued participation of the members of a Twitter-based professional learning community. More than 600,000 tweets …

Grasp And Stress Analysis Of An Underactuated Finger For Proprioceptive Tactile Sensing, Mahyar Abdeetedal, Mehrdad Kermani Ph.D., P.Eng.

Electrical and Computer Engineering Publications

This paper presents the design and evaluation of a new sensorized underactuated self-adaptive finger. The design incorporates a two-degrees-of-freedom link-driven underactuated mechanism with an embedded load cell for contact force measurement and a trimmer potentiometer for acquiring joint variables. The utilization of proprioceptive (internal) sensors results in tactile-like sensations in the finger without compromising the size and complexity of the proposed design. To obtain an optimum finger design, the placement of the load cell is analyzed using finite element method. The design of the finger features a particular rounded shape of the distal phalanx and specific size ratio between the …

High-Resolution Qpf Uncertainty And Its Implications For Flood Prediction: A Case Study For The Eastern Iowa Flood Of 2016, Bong Chul Seo, Felipe Quintero, Witold F. Krajewski

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study addresses the uncertainty of High-Resolution Rapid Refresh (HRRR) quantitative precipitation forecasts (QPFs), which were recently appended to the operational hydrologic forecasting framework. In this study, we examine the uncertainty features of HRRR QPFs for an Iowa flooding event that occurred in September 2016. Our evaluation of HRRR QPFs is based on the conventional approach of QPF verification and the analysis of mean areal precipitation (MAP) with respect to forecast lead time. The QPF verification results show that the precipitation forecast skill of HRRR significantly drops during short lead times and then gradually decreases for further lead times. The …

Geophysical Assessment Of Subsurface Soil Conditions Using Capacitively Coupled Resistivity, Folaseye Coker

Graduate Theses and Dissertations

The purpose of this research is to explore the applicability of Capacitively-Coupled Resistivity (CCR) as an improvement on traditional drilling and sampling methods for subsurface soil investigations. The CCR method could be used to identify critical locations for drilling and sampling such as expansive clay layers and anomalies (sinkholes, unknown landfills, etc.) rather than uniformly sampling across a site. CCR surveys were performed at Alpena, Arkansas along a highway expansion project changing US 62 from a two lane to four lane highway, and at Alton, Illinois along the Mel Price Levee, a 5.2 mile levee along a portion of the …

Computer Modeling Of Close-To-Ground Tornado Wind-Fields For Different Tornado Widths, Mohammadhossein Kashefizadeh

Graduate Theses and Dissertations

Tornadoes induce different wind forces on buildings than straight-line (SL) winds. The tangential velocity (Vθ) of tornados is the main parameter that causes damage to the buildings. In-field tornado measurements cannot evaluate the tornado’s Vθ at less than 20m above ground level (AGL). The laboratory tornado simulators suggest that the Swirl ratio (S) and the radius (ro) are the most influential factors affecting Vθ. However, due to scaling problems, laboratory simulators cannot report the Vθ for elevations less than 10m AGL. Well refined computational fluid dynamics (CFD) models can evaluate the Vθ at less than 10m AGL. However, the CFD …

Proposed Astm Standard For The Stokoe-Type Resonant Column Torsional Shear Device, Anh Tuan Tran

Graduate Theses and Dissertations

Resonant Column Torsional Shear (RCTS) testing has become one of the most commonly used methods for determining laboratory soil stiffness and soil damping. The RCTS test has been accepted and is commonly utilized during the permitting of new nuclear facilities. However, there is still no available public standard for performing RCTS tests using the Stokoe-type device. Therefore, an ASTM standard for calibration and performance of RCTS tests using the Stokoe-type RCTS device is presented herein. Data collected using the Stokoe-type RCTS devices at the University of Arkansas (UofA) and at the Norwegian Geotechnical Institute (NGI) also aided in the development …

Testing And Development Of Pre-Stressed Cfrp Retrofit Strategies For Controlling Fatigue Cracking In Steel Waterway Lock Gate Structures, Maggie Langston

Graduate Theses and Dissertations

Steel waterway lock gates across the national inland waterway transportation network are reaching and exceeding their intended service life, often experiencing component failures that lead to service interruptions. Unscheduled maintenance and repair of lock gates can be expensive and cause economic ripples throughout the entire inland waterway network. These lock gate component failures are often caused by fatigue cracking from repeated loading during operation. This thesis develops and tests a prestressed carbon fiber reinforced polymer (CFRP) fatigue retrofit for controlling fatigue demands within lock gate components. The study expands upon a recent analytical work by Lozano (2017) by experimentally investigating …

Graduate School Of Engineering And Management Catalog 2018-2019, Graduate School Of Engineering And Management, Air Force Institute Of Technology

AFIT Documents

The Graduate Catalog represents the offerings, programs, and requirements in effect at the time of publication.

Development Of Iowa Dot Combination Bridge Separation Barrier With Bicycle Railing, Chaz M. Ginger

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

The Iowa Department of Transportation typically builds separation barriers between vehicle and pedestrian/bicycle facilities when sidewalks or trails are present on vehicular bridges. Currently, Iowa DOT employs a combination bridge rail that utilizes a concrete parapet that previously had been successfully evaluated to National Cooperative Highway Research Program (NCHRP) Report 350 Test Level 4 (TL-4) criteria for these situations. While the parapet had been successfully evaluated, the combination bridge rail system as a whole had not been evaluated to any crash test standards. Iowa DOT desired that researchers at Midwest Roadside Safety Facility (MwRSF) design and test a combination bridge …

Computational Study On The Cu-Rich Side Of Aluminum-Copper Phase Diagram, Khaled Ahmed Hirmas

Material Science and Engineering Dissertations - Archive

Cu-rich side of Al-Cu phase diagram has not been studied extensively as the Al-rich side. It is well established that a one-phase (a phase) exists at 300oC between the 82% Cu and pure Cu, and at the eutectic temperature (1032oC) between 86% Cu and pure Cu, a phase, when quenched from above 600oC and subjected to annealing below about 300oC, or deformation, show ordering effects in resistivity, heat capacity, diffuse X-ray, microstructure, and in mechanical properties. This has been studied to determine whether these effects are due to short-range or long-range ordered domain [1]. The present computational study is to …

Lifepo4 Batteries: Impact Of Highly Parallel Packs On Load Distribution And Cycle Life, Caroline Storm Westenhover

Electrical Engineering Dissertations - Archive

The United States Navy is considering Li-ion batteries for use as a primary power source for future naval shipboard pulsed-power applications. To supply sufficient power to a load, electrochemical cells are connected in series and parallel to create a higher voltage and higher capacity battery. The simplest way of connecting multiple cells in parallel is to tie all positive terminals together, all negative terminals together, and then electrically treat the array of cells as a single cell within the larger battery. In this configuration, a single battery management system (BMS) can be used to manage N parallel cells but there …

Multi-Physics Design Optimization Of 2d And Advanced Heterogenous 3d Integrated Circuits, Pavan Rajmane

Mechanical and Aerospace Engineering Dissertations - Archive

The convergence and miniaturization of computing and communications dictate building up rather than out. As planar device miniaturization continues to its ultimate limits, the complexity of circuit interconnections for 2-D devices becomes a limitation for performance and drives up power dissipation [1]. Failure analysis and its effects are major reliability concerns in electronic packaging. More accurate fatigue life prediction can be obtained after the consideration of all affecting loads on the electronic devices. In this study, an attempt is made to analyze 3 types of packages i.e. Wafer Level Chip Scale Package (WCSP), Quad Flat No-Lead (QFN) Package and 2-Die …

A Framework For Optimal Path Planning And Nonlinear Guidance For Autonomous Mobile Robots, Paul A. Quillen

Mechanical and Aerospace Engineering Dissertations - Archive

The purpose of this research is to investigate methods and technology for enhancing autonomous capabilities for mobile robots. The measures of autonomy which are specifically covered in this dissertation pertain to a mobile robot’s ability to make decisions and act, in other words guidance and control. This dissertation puts forth a framework using optimal path planning and nonlinear guidance techniques to address these matters. The path plans are synthesized using a numerical navigation function algorithm that will form its potential contour levels based on the “minimum control effort” of the system. Additionally, extensions of the path planning algorithm in the …

Numerical And Experimental Study Of Single Phase And Multiphase Droplet Dynamics On Electrowetting-On-Dielectrode Digital Micro-Fluidics, Mun Mun Nahar

Mechanical and Aerospace Engineering Dissertations - Archive

In the recent years, significant efforts have been devoted to the development of droplet based lab-on-a-chip devices of which advantages include being programmable and reconfigurable. Among various droplet flow based microsystems [1-5], electrowetting on dielectric (EWOD) digital microfluidics has many advantages, such as rapid switching response, no joule heating, no need for moving parts like pumps and valves, and most importantly low power requirement [6]. Basic droplet handling techniques - droplet dispensing, transporting, merging and splitting - can be done by sequentially activating and deactivating specific electrodes, which allows to address each droplet individually and to perform various unit processes …

A Multiphysics Study Of Interfacial Properties Of 3d Printed Filaments, Alireza Rezaee

Mechanical and Aerospace Engineering Dissertations - Archive

Fused Deposition Modeling has become the most popular 3-D printing method over the last decade. Due to its potential to save time, cost and, labor, there is a great deal of interest to use this technique for production of functional load carrying parts and assemblies in bio-medical, automotive, aerospace, and oil and gas industries. In general, materials used in FDM process are isotropic; however, parts printed using FDM process show anisotropic mechanical properties with inconsistent properties in the transverse direction to the filaments’ cross-section. This anisotropic behavior is due to the fabrication process, and the inconsistency in the transverse mechanical …

Characterizing Contamination To Expand Ashrae Envelope In Airside Economization And Thermal And Reliability In Immersion Cooling Of Data Centers, Jimil Manojbhai Shah

Mechanical and Aerospace Engineering Dissertations - Archive

The Datacom facility which comprises rooms or closets used for communication, computers/servers or electronic equipment requires cooling unit which consumes 31% (23% HVAC cooling + 8% HVAC fans) of overall energy. The ASHRAE TC9.9 subcommittee, on Mission Critical Facilities, Data Centers, Technology Spaces, and Electronic Equipment, has suited the data center’s executives by permitting brief period outings of the environmental conditions outside the prescribed temperature-humidity range, into passable extents A1-A3. To comprehend the expanding server densities and the required cooling vitality costs, data center operators are falling back on cost cutting measures. For instance, they are not firmly controlling the …

Woods Tire Model, Priyank Vasant Nandu

Mechanical and Aerospace Engineering Theses - Archive

The performance of a racecar in a maneuver is almost totally determined by the characteristics of the tires and the suspension setup. If the suspension is properly tuned for the maneuver, then the limiting factor is the tire. Therefore, any racecar design and performance analysis must start with a full description of the performance of the tire [1]. Mathematical models for tire performance such as the Pacejka model have been in use for a long time and have become the standard for expressing how a tire will perform dynamically. It comprises of curve fit to experimental data and requires about …

Achieving Novel Functionalities In Semiconductor-Crystalline Oxide Heterostructures Through Electrical And Structural Coupling, Kamyar Ahmadi-Majlan

Material Science and Engineering Dissertations - Archive

Creating new materials that exhibit enhanced or novel behaviors is essential to meet the technological challenges we face today. Complex oxides are perfect candidates to overcome these challenges due to the range of electronic, optical, and ionic properties they exhibit. The research presented here, mainly focuses on overcoming two important challenges in oxide electronics. First,the ability of epitaxially growing multifunctional oxides on conventional semiconductor substrates and second, the successful integration of multifunctional oxide properties on semiconductors Oxide molecular beam epitaxy was utilized to grow transition metal oxides with unprecedented control, layer-by-layer, at the atomic scale. Such control of growth enables …

An Investigation Of The Plasma Electrolytic Oxidation Mechanism For Coating Of Alumina-Zirconia Nanocomposite, Nastaran Barati

Material Science and Engineering Dissertations - Archive

Plasma Electrolytic Oxidation (PEO) is an electrochemical surface modification technique which is able to coat ceramic coatings on valve metals from either cationic or anionic species in an aqueous electrolyte. Applying high voltage in the range of 300-600 V is required to achieve crystalline phases. PEO is a clean technology which offers several benefits including high deposition rates, excellent adhesion strength and mechanical properties. One of the interesting capabilities of the PEO process is its ability to form composite coatings. The following work aims to study the growth mechanism of nanocomposite layers coated by PEO. Two experimental routs have been …

Spectral-Domain Phase-Sensitive Interferometry For Real-Time Probing Of Electrodeposition Processes, Yujen Chiu

Material Science and Engineering Dissertations - Archive

Electrodeposition is a simple, versatile and scalable method for depositing thin metal films on conductive substrates, and it has long been used in large-scale industrial processes for metal film coating. In the last two decades, electrodeposition has entered into the manufacturing processes of electronic devices. Electrodeposition of Cu has become the standard process for the backend processes for almost all microelectronic devices. Electrodeposition of Cu and magnetic materials are used in the fabrication of write/read head in computer hard disk drive. More recently, a unique electrodeposition process, under potential deposition (UPD), has been utilized for atomic layer deposition to generate …

Investigation Of Surface Contamination In A Cu-Based Al Alloy Occurring During Tem Sample Preparation, Kelly Claunch

Material Science and Engineering Theses - Archive

This thesis investigates the nature of surface contamination originating from the jet-polishing process on Cu-6 wt% Al TEM disks. During previous TEM imaging and diffraction analysis performed by our group, surface contamination particles, roughly 15-60 nm in diameter, were observed on the surface of the jet-polished TEM disks. Further, TEM diffraction analysis revealed that the contamination particles were growing epitaxially on the Cu matrix. HR-SEM was used to characterize the surface contamination in terms of shape, size, composition, and distribution on the surface of the disks. Through extensive HR-SEM imaging, it was found that surface contamination particles are present on …

Detection Of Molecular Biomarkers Involved In The Induction Of Emt, Migration And Invasion, And Drug Resistance In Breast Cancer Cells In 3d Confinement, Tamara Nicole Hill

Bioengineering Dissertations - Archive

Standard-of-care regimes for cancer treatment have become more effective and sophisticated over the last decade due to research developments which facilitate specific targeting of treatments to certain cancers, and the ability to provide specialized care to cancer patients. However, cancer treatments overall still fall short of preventing spread of disease from the primary tumor to secondary sites where they settle and form new more aggressive tumors. It is this stage of disease progression which results in the majority of cancer deaths. The long-term goal of this research is to develop a system for the effective high throughput screening of chemotherapeutic …

Fabrication And In Vitro Characterization Of An Implant For The Detection Of Metastatic Cancer Cells, Carlos Martin Cantu

Bioengineering Theses - Archive

Greater than 90% of cancer related deaths are due to metastasis (Hayes & Wicha, 2011). Since current conventional techniques detect the disease by the time that it has become systemic, our lab has developed a hydrogel based cancer trap that can attract metastatic cancer cells via cytokine release. However, for continual monitoring and accessibility to the gel, an implant is needed for delivery, retention, and retrieval of the gel. The research undergone in this thesis seeks to develop such a method. Namely, the objective was to develop a polylactide (PLA) based implant that is capable of delivering and retaining a …

Evaluation And Strengthening Of Elevated Slab On Grade With Fiber-Reinforced Polymer (Frp) Laminates, Natawut Chaiwino

Civil Engineering Dissertations - Archive

Elevating a residential house appears to be one of the most effective techniques to eliminate or alleviate flood losses. In general, the elevation procedures involve raising a house as well as its typical slab-on-grade (SOG) foundation and supporting it with an additional support system. The unconcerned effects of the drastic changes in support condition could lead to severe structural damages and failure of houses. After elevated, thus, such slabs must be properly supported and retrofitted, for which the available methodology and know-how is almost nonexistent. The fiber reinforced polymer (FRP) application, considered as a promising technique in the rehabilitation of …

Development Of Mussel Inspired Nanocomposite Adhesives For Biomedical Applications, Nikhil Pandey

Bioengineering Dissertations - Archive

Popular bioadhesives, such as fibrin, cyanoacrylate and albumin–glutaraldehyde-based materials, have been applied for clinical applications in wound healing, drug delivery, and bone and soft tissue engineering; however, their performances are limited by weak adhesion strength and rapid degradation. The long-term goal of this research is to develop a strong tissue adhering nanocomposite for tissue interfacing and wound healing applications. We begin by developing a mussel-inspired, nanocomposite–based, biodegradable tissue adhesive by blending poly (lactic-co-glycolic acid) (PLGA) or N-hydroxysuccinimide modified PLGA nanoparticles (PLGA-NHS) and polydopamine nanoparticles with mussel-inspired polymers. Adhesive strength measurement of the nanocomposites on porcine skin-muscle constructs revealed that the …