Engineering Commons^™

Speckle Effects In Target-In-The-Loop Laser Beam Projection Systems, Mikhail Vorontsov

Electro-Optics and Photonics Faculty Publications

In target-in-the-loop laser beam projection scenarios typical of remote sensing, directed energy, and adaptive optics applications, a transmitted laser beam propagates through an optically inhomogeneous medium toward a target, scatters off the target’s rough surface, and returns back to the transceiver plane. Coherent beam scattering off the randomly rough surface results in strong speckle modulation in the transceiver plane. This speckle modulation has been a long-standing challenge that limits performance of remote sensing, active imaging, and adaptive optics techniques. Using physics-based models of laser beam scattering off a randomly rough surface, we show that received speckle-field spatial and temporal characteristics …

Graphene Field Effect Transistors For Highly Sensitive And Selective Detection Of K+ Ions, Hongmei Li, Yihao Zhu, Md. Sayful Islam, Md. Anisur Rahman, Kenneth B. Walsh, Goutam Koley

Publications

Graphene-based ion sensitive field effect transistors (GISFETs) with high sensitivity and selectivity for K+ ion detection have been demonstrated utilizing valinomycin based ion selective membrane. The performance of the GISFETs for K+ ion detection was studied in various media over a concentration range of 1 μM–2 mM. The sensitivity of the sensor was found to be >60 mV/decade, which is comparable to the best Si-based commercial ISFETs, with negligible interference found from Na+ and Ca2+ ions in high concentration. The sensor performance did not change significantly in Tris–HCl solution or with repeated testing over a period of two months highlighting …

Extended Lamer Synthesis Of Cobalt Doped Ferrite, Benjamin D. Fellows, Sarah Sandler, Jacob Livingston, Kristin Fuller, Lotanna Nwandu, Sarah Timmis, Kayla A. Lantz, Morgan Stefik, O. Thompson Mefford

Publications

Nonstoichiometric cobalt ferrite nanoparticles have drawn interest in magnetically mediated energy delivery due to their high magnetocrystalline anisotropy and their high peak loss frequency. The use of an extended LaMer synthesis allows for size control of the doped particles up to a threshold core diameter of 18 nm. Above this diameter, particles become unstable and drop out of suspension, allowing for further nucleation events to occur. This leads to a cyclic nucleation, growth, and destabilization regime seen during the course of the reaction. Using the size control of the extended LaMer synthesis technique, we examine the specific absorption rate (SAR) …

Expanding Efficiency: Women's Communication In Engineering, Jennifer C. Mallette

English Literature Faculty Publications and Presentations

As engineering fields strive to be more inclusive of women, focusing on perceptions of women's work is vital to understanding how women can succeed and the limitations they may face. One area in need of more attention is the connection between communication and women's experiences in engineering. This article examines the gendered nature of writing labor in engineering, focusing on case studies of three women who were able to use writing effectively, yet how communication emerged as a gendered form of labor subject to gendered perceptions. While these women's communication skills led to professional success, their association with writing echoes …

Exploring Energy, Comfort, And Building Health Impacts Of Deep Setback And Normal Occupancy Smart Thermostat Implementation, Zachary Ethan Alderman

Graduate Theses and Dissertations

As smart thermostat adoption rates continue to increase, it becomes worthwhile to explore what unanticipated outcomes may result in their use. Specific attention was paid to smart thermostat impacts to deep setback and normal occupancy states in a variety of conditions while complying with the ventilation and temperature requirements of ASHRAE 90.2-2013. Custom weather models and occupancy schedules were generated to efficiently explore a combination of weather conditions, building constructions, and occupancy states. The custom modeling approach was combined with previous experimental data within the Openstudio graphics interface to the EnergyPlus building modeling engine. Results indicate smart thermostats add the …

On The Fatigue Of Headed Shear Studs In Steel-Concrete Composite Bridge Girders, Brianna Laurene Ovuoba

Graduate Theses and Dissertations

Shear connectors are commonly used in steel bridges to join the concrete deck and steel superstructure, providing a mechanism for shear transfer across the steel-concrete interface. The most common shear connector is the headed shear stud. In the current AASHTO LRFD Bridge Specifications on composite design, shear stud fatigue often governs over static strength, and a large number of shear connectors often result. This dissertation investigates headed shear stud fatigue capacities and demands, and provides insight into conservancies in existing design specifications through examination of existing high-traffic bridge performance.

To investigate stud capacity, a total of six high-cycle fatigue tests …

Development Of An Internal Camera-Based Volume Determination System For Triaxial Testing, Sean Elliott Salazar

Graduate Theses and Dissertations

Accurate measurement of axial, radial, and volumetric strain parameters are critical to the understanding of phase relationships and the constitutive behavior for saturated and unsaturated soils. The use of photographic monitoring techniques for laboratory-based measurement of these parameters have become common. A novel technique that utilized camera instrumentation located within the triaxial testing cell was developed and validated. By placing the instrumentation inside of the cell, instead of the instrumentation being located outside of the cell, the technique eliminated cumbersome corrections required to account for optical distortions due to 1) the refraction of light at the confining fluid-cell wall-atmosphere interfaces, …

Cost-Savings Of Implementing Site-Specific Ground Motion Response Analysis In Design Of Mississippi Embayment Bridges, Ethan Ryan Benton Baker

Graduate Theses and Dissertations

Deep dynamic site characterization and a site-specific ground motion response analysis (SSGMRA) were conducted for a bridge site in Monette, Arkansas. The SSGMRA indicated the design acceleration response spectrum determined using the American Association of State Highway and Transportation Officials (AASHTO) general seismic procedure could be reduced by 1/3 for the short period range due to attenuation of the short-period ground motions. The steel girder pile-bent bridge, originally designed using the AASHTO general seismic design procedure, was redesigned using the updated seismic demands estimated from SSGMRA. A cost-savings analysis was then conducted to determine the potential savings associated with conducting …

An Evaluation Of Borehole Hydraulic Conductivity Equations And Field Determined Soil Water Characteristic Curves, Johnathan Dale Blanchard

Graduate Theses and Dissertations

The methods utilized to determine the hydraulic conductivity of compacted clay liners (CCLs) are of importance for safe guarding the environment from landfill leachate. Therefore, the methods utilized in the analysis of the Two Stage Borehole (TSB) test, as described in the ASTM D6391-11 (Method A, B, and C) standard, were evaluated. Data from hydraulic conductivity tests, as performed on three test pads, were utilized to review the ASTM D6391-11 equations. Additionally, two test pads were instrumented with volumetric water content and soil water matric potential sensors to facilitate the determination of field-obtained soil water characteristic curves (SWCCs) and hydraulic …

Automated Pin-Dot Marking Effects On A709-Gr50 Steel Plate Fatigue Capacity, Michael Andrew Noernberg

Graduate Theses and Dissertations

During fabrication of multi-piece steel bridge assemblies, markings are often made on the steel surface to identify/track individual pieces or to provide reference for fabrication layout or later erection. Automated marking methods such as computer numerically controlled (CNC) pin-dot marking offer fabrication efficiencies; however, for marked steel sections subjected to frequent or repeated loading (i.e. bridge girders) many code specifications require experimental testing to verify any marking effects on fatigue capacity. In this study, the effects of automated pin-dot markings on the fatigue capacity of A709-Gr50 bridge steel are experimentally investigated from 13 specimens considering 2 marking frequencies (corresponding to …

Evaluation Of Water Resources And Hydraulic Influences In The Restoration Of The Western Part Of The Mesopotamian Marshlands, Ali Kareem Al-Quraishi

Graduate Theses and Dissertations

The purpose of this study is to assess the water resources and water conveyance system of the western part of the Mesopotamian marshes (Al-Hammar marsh) as well as develop a water conveyance system to distribute water throughout the western Al-Hammar marsh. These processes are significant to identify the current restoration problems and help to create restoration strategies for the marsh. Also, proper management strategy to the Al-Hammar marsh is necessary to preserve the marsh ecosystem, irrigate lands, and provide domestic necessities in the villages.

The overall project is divided into three main chapters which address the current ecological and hydrological …

Dem Study Of A Single Stone Column In A Clayey Stratum, Anibal Enrique Santos

Graduate Theses and Dissertations

Aggregate piers are an alternative ground improvement technique used for improving the bearing capacity and reducing the total and differential settlement of foundations supported on compressible soils. The piers are composed of a series of vibrationally compacted aggregate lifts from a desired depth up to the finished foundation level. The shear strength of the coarse-grained material comprising an aggregate pier is defined by its internal friction angle. There are several factors affecting the friction angle of the granular material that include: confining stress, particle shape, relative density and particle distribution (gradation). These factors are not directly considered in the design …

3d Printed Pcu/Uhmwpe Polymeric Blends For Artificial Knee Meniscus, Raissa Araujo Borges

Graduate Theses and Dissertations

3D printing was used to fabricate porous artificial knee meniscus material from biocompatible polymeric blends of polycarbonate-urethane (PCU) and ultra-high-molecular-weight polyethylene (UHMWPE) to enable “weep” lubrication that mimics the native meniscus. 3D printed and molded pure PCU, as well as molded PCU and UHMWPE, were used for comparison. Preliminary printing was done to evaluate the impact of process parameters on the results. The samples were subject to a variety of rotational oscillating friction and wear tests under simulated body fluid and loading conditions to replicate the natural motion of the knee. Results show that 3D printed PCU samples yielded a …

A Humidity-Controlled Fast Integrated Mobility Spectrometer (Hfims) For Rapid Measurements Of Particle Hygroscopic Growth, Tamara Pinterich, Steven R. Spielman, Yang Wang, Susanne V. Hering, Jian Wang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

We present a humidity-controlled fast integrated mobility spectrometer (HFIMS) for rapid particle hygroscopicity measurements. The HFIMS consists of a differential mobility analyzer (DMA), a relative humidity (RH) control unit and a water-based FIMS (WFIMS) coupled in series. The WFIMS (Pinterich et al., 2017) combines the fast integrated mobility spectrometer (Kulkarni and Wang, 2006a, b) with laminar flow water condensation methodologies (Hering and Stolzenburg, 2005; Spielman et al., 2017). Inside the WFIMS, particles of different electrical mobilities are spatially separated in an electric field, condensationally enlarged and imaged to provide 1 Hz measurements of size distribution spanning a factor of ∼3 …

Meeting Real-Time Constraint Of Spectrum Management In Tv Black-Space Access, Zhongyuan Zhao

School of Computing: Technical Reports

The TV set feedback feature standardized in the next generation TV system, ATSC 3.0, would enable opportunistic access of active TV channels in future Cognitive Radio Networks. This new dynamic spectrum access approach is named as black-space access, as it is complementary of current TV white space, which stands for inactive TV channels. TV black-space access can significantly increase the available spectrum of Cognitive Radio Networks in populated urban markets, where spectrum shortage is most severe while TV whitespace is very limited. However, to enable TV black-space access, secondary user has to evacuate a TV channel in a timely manner …

Sustainable Clean Coal Technology With Power And Methanol Production, Xiaomeng Wang

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

The coal-based chemical process is still indispensable in modern society due to the worldwide vast reserves and popular price of coal. Power generation and chemical production from coal still play an important role in the global chemical industrial market. Electricity generation and chemical production from coal is still the trend as long as the coal is plentiful and inexpensive. Modern chemical industry aims at sustainability and hence the development of clean coal technologies is critical.

Coal-based methanol economy, as an attractive liquid transportation fuel as well as an essential intermediate chemical feedstock, can fill a possible gap between declining fossil …

Label-Free Refractive Index Sensing With Free-Space Coupled Photonic Crystal Slabs, Yonghao Liu

Electrical Engineering Dissertations - Archive

Label-free optical resonance sensors can detect small changes of refractive index (RI), which could be used for biochemical molecular detection, drug screening or gas detection. One of the most critical parameters in these sensors is the sensor detection limit (DL). Reducing DL can be achieved by increasing the resonance quality factors (Q) and the spectral sensitivity (S). Another critical research challenge in these sensors is the sensing specificity. In this thesis, based on Fano resonance principle in two-dimensional photonic crystal slabs (PCS) and the integration with gas separation columns, we investigated various free-space coupled on-chip optical resonance sensors for both …

Label Free Optical Detection Of Electrical Activity In Mammalian Neurons, Sarmishtha Satpathy

Electrical Engineering Dissertations - Archive

We describe an optical technique for label-free detection of the action potential in cultured mammalian neurons. Induced morphological changes due to action potential propagation in neurons are optically interrogated with a phase sensitive interferometric technique. Optical recordings composed of signal pulses mirror the electrical spike train activity of individual neurons in a network. The optical pulses are transient nanoscale oscillatory changes in the optical path length of varying peak magnitude and temporal width. Exogenous application of glutamate to cortical neuronal cultures produced coincident increase in the electrical and optical activity; both were blocked by application of a Na-channel blocker, Tetrodotoxin. …

Large Dimensional Analysis And Optimization For Massive Mimo Wireless Networks, Longwei Wang

Electrical Engineering Dissertations - Archive

The Last decade has seen a massive growth of wireless devices. Demands for high capacity and massive connectivity always increases. To meet the these requirements, massive multiple-input multiple-output (MIMO) technology is proposed for the next generation wireless systems. With massive antenna arrays at the BS, the channel vectors between the users and the BS are asymptotically orthogonal, and the intercell interference can be eliminated with simple linear processing method. The effects of fast fading, and uncorrelated noise tend to disappear as the number of BS station antennas grows large. In this thesis, we mainly focus on the performance analysis and …

On Chip Hybrid Photonic Crystal Surface Emitting Lasers, Shih-Chia Liu

Electrical Engineering Dissertations - Archive

We report here the design and experimental demonstration of optically pumped photonic crystal bandedge membrane lasers on silicon-on-insulator (SOI) and on bulk silicon (Si) substrates, based on heterogeneously integrated InGaAsP multi-quantum-well membrane layers transfer printed onto patterned photonic crystal cavities. Single mode lasing under room-temperature operation was observed at 1542 nm, with excellent side mode suppression ratio greater than 31.5 dB, for the laser built on SOI substrate. For the laser built on bulk Si substrate, the improved thermal characteristics are favorable for lasers operating potentially at higher temperatures and higher power. We also report the experimental and theoretical investigations …

Molecularly Engineered Surfaces For Early Cancer Diagnosis, Mohammad Raziul Hasan

Electrical Engineering Dissertations - Archive

Early detection of cancer can have immediate and significant impact on effective treatments for cancer patients and better disease prognosis. In the early stage of cancer, symptoms are initially expressed at molecular and cellular scales. Identification and capture of cancer cells can greatly advance cancer research. This research work is aimed to introduce novel biosensors and technologies for early cancer detection. We developed a one-step method to create nanotextured polymer substrates and showed the effect of surface nanotexture on cancer cell adhesion and cell surface interactions. The nanotextured surface was functionalized with an antibody to selectively capture cancer cells from …

Massive Mimo Performance Analysis And Radar Sensor Networks Based Target Detection, Ganlin Zhao

Electrical Engineering Dissertations - Archive

In this dissertation, we apply massive multiple-input-multiple-output (MIMO) performance analysis and radar target detection based on radar sensor networks(RSN). In recent years, massive MIMO draws great interest for wireless communication re- searchers. As a highly scalable technology for 5G networks, massive MIMO will meet the increasing demand for wireless throughput. Also, radar target detection is also an important topic for military and civilian applications. Improving detection accuracy when target is embedded in strong background clutter is a challenging task. In Chapter 2, we investigate scaling law of theoretical transmission capacity limit in an uplink multi-user MIMO system. In 5G network …

Rotordynamic Enhancement By Utilizing The Controlled Hydrostatic Injection Of Hybrid Air Foil Bearing, Behzad Zamanian Yazdi

Mechanical and Aerospace Engineering Dissertations - Archive

Air foil bearings (AFBs) are introduced as promising bearings for oil-free turbomachinery applications. Air foil bearing (AFB) technology has made substantial advancement during the past decades and found its applications in various small turbomachinery. AFBs provide reliable operation at high speed and high temperature with negligible power loss. However, rotordynamic instability, friction and drag during the start/stop, and thermal management are still challenges for further application of the technology. Hybrid Air Foil Bearing (HAFB) technology utilizes the radial injection of externally pressurized air into the traditional hydrodynamic AFB’s film thickness through orifices attached to the top foil. HAFB is one …

Optimization Of Aircraft Tow Steered Composite Wing Structures, Micheal Chamberlain Henson

Mechanical and Aerospace Engineering Dissertations - Archive

An efficient methodology for design of aircraft composite wing structures is presented. The developed approach provides a flexible and integrated strategy to leverage advantages of composite material tow steering to achieve more effective wing designs. This is accomplished by including the coupling between OML geometry, aerodynamics and structural response. Structural and aerodynamic analyses are derived from parametric aircraft geometry and assembled into a framework for aero-structural wing sizing. A Ritz equivalent plate solution is extended to model composite materials with variable fiber path geometry. The structural modeling approach is implemented to automate creation of both Ritz and finite element analyses. …

A Micromechnics Approach To Predicting The Onset Yielding Envelope Of Particulate Composite Materials, Behrooz Karimi

Mechanical and Aerospace Engineering Dissertations - Archive

Composite materials fail for various reasons and extensive research has been conducted both experimentally and theoretically. However, theoretical prediction of composite failure by yielding seems scarce. Adding reinforcing elements to matrix significantly affects the structural behavior of composite materials. The inserted particles on one hand obstruct the progress of cracks and on the other hand cause stress concentration on the interface of the particle-matrix and eventually influence the ultimate strength of the material. In this research, we study the interface stresses and strength in particulate reinforced composites under uniform mechanical and thermal loading. We theoretically obtain failure envelopes for particulate …

Towards The Fabrication Of Bioresorbable Constructs With Customized Properties Using Additive Manufacturing, Prashanth Ravi

Mechanical and Aerospace Engineering Dissertations - Archive

Additive Manufacturing (AM) has been employed to fabricate medical constructs for over two decades. This dissertation investigates the effects of AM process parameters on raster level geometric features and structural properties of bioresorbable constructs. The development of an open architecture custom multi-process 3D printer employed for fabricating bioscaffolds and test structures is discussed. Bioresorbable polymers including a newly synthesized radiopaque polymer, poly (glycerol sebacate fumarate) gadodiamide (Rylar) and medical grade poly-L-lactic acid (PLLA) were investigated. In the first part, the effects of process parameters on raster geometry were investigated to aid in the fabrication of structures with improved geometric features …

Numerical Study Of Droplet Evaporation, Ritul Gandhi

Mechanical and Aerospace Engineering Theses - Archive

Droplet evaporation plays a vital role in various engineering fields such as air/fuel premixing, inkjet printing and many more. The high rate of power dissipation from the integrated circuits and chips of electronic devices creates a need for cooling it to achieve their optimal functionality. The high rate of cooling can be achieved by thin film evaporation of water by phase change as compared to the air cooling methods. Therefore, the study of droplet evaporation is necessary to understand the underlying physics and effects of different parameters on cooling performance. Numerical study of droplet evaporation has been done by using …

Space Launch Vehicle Design: Conceptual Design Of Rocket Powered, Vertical Takeoff, Fully Expendable And First Stage Boostback Space Launch Vehicles, David Michael Woodward

Mechanical and Aerospace Engineering Theses - Archive

Engineering design can be broken down into three phases: conceptual design, preliminary design, and detailed design. During the conceptual design phase, several potential configurations are studied towards the identification of the baseline vehicle. Although the least amount of detail is known about the design during the early conceptual design phase, the decisions made during this phase lock in major features effecting life-cycle cost and overall product success. As the next big space race begins, it is critically important to have a readily available tool for launch vehicle designers that is intuitive to use, easy to modify, cost effective, and provides …

A Methodology For Topology And Lattice Structure Optimization Of A Cargo Drone Motor Mount, Nagadurga Srinivas Sripada

Mechanical and Aerospace Engineering Theses - Archive

This work discusses a CAE driven methodology for designing a lightweight component by performing structural configuration on a given package space, creating a closed surface along this configuration using an interactive geometric modeling tool, and lastly generating lattice members that provide the required stiffness for the structure. The design process is explained starting with topology optimization performed on a single block with specific design constraints. It describes the effect of different parameters on the optimized results and how to analyze these results based on a given volume fraction constraint with the objective of minimizing the compliance. It then talks about …

Region Based Convolutional Neural Networks For Object Detection And Recognition In Adas Application, Sachit Kaul

Mechanical and Aerospace Engineering Theses - Archive

Object Detection and Recognition using Computer Vision has been a very interesting and a challenging field of study from past three decades. Recent advancements in Deep Learning and as well as increase in computational power has reignited the interest of researchers in this field in last decade. Implementing Machine Learning and Computer Vision techniques in scene classification and object localization particularly for automated driving purpose has been a topic of discussion in last half decade and we have seen some brilliant advancements in recent times as self-driving cars are becoming a reality. In this thesis we focus on Region based …