Engineering Commons^™

A Patterned Single Layer Graphene Resistance Temperature Sensor, Benyamin Davaji, Hak Dong Cho, Mohamadali Malakoutian, Jong-Kwon Lee, Gennady Panin, Tae Wong Kang, Chung-Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

Micro-fabricated single-layer graphenes (SLGs) on a silicon dioxide (SiO₂)/Si substrate, a silicon nitride (SiN) membrane, and a suspended architecture are presented for their use as temperature sensors. These graphene temperature sensors act as resistance temperature detectors, showing a quadratic dependence of resistance on the temperature in a range between 283 K and 303 K. The observed resistance change of the graphene temperature sensors are explained by the temperature dependent electron mobility relationship (~T⁻⁴) and electron-phonon scattering. By analyzing the transient response of the SLG temperature sensors on different substrates, it is found that the graphene sensor …

An Efficient And Cost Effective Fpga Based Implementation Of The Viola-Jones Face Detection Algorithm, Peter Irgens, Curtis Bader, Theresa Lé, Devansh Saxena, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

We present an field programmable gate arrays (FPGA) based implementation of the popular Viola-Jones face detection algorithm, which is an essential building block in many applications such as video surveillance and tracking. Our implementation is a complete system level hardware design described in a hardware description language and validated on the affordable DE2-115 evaluation board. Our primary objective is to study the achievable performance with a low-end FPGA chip based implementation. In addition, we release to the public domain the entire project. We hope that this will enable other researchers to easily replicate and compare their results to ours and …

Axially Uniform Magnetic Field-Modulation Excitation For Electron Paramagnetic Resonance In Rectangular And Cylindrical Cavities By Slot Cutting, Jason Walter Sidabras, James Richie, James S. Hyde

Electrical and Computer Engineering Faculty Research and Publications

In continuous-wave (CW) Electron Paramagnetic Resonance (EPR) a low-frequency time-harmonic magnetic field, called field modulation, is applied parallel to the static magnetic field and incident on the sample. Varying amplitude of the field modulation incident on the sample has consequences on spectral line-shape and line-height over the axis of the sample. Here we present a method of coupling magnetic field into the cavity using slots perpendicular to the sample axis where the slot depths are designed in such a way to produce an axially uniform magnetic field along the sample. Previous literature typically assumes a uniform cross-section and axial excitation …

Effects Of Training Intensity On Locomotor Performance In Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study, Gabrielle Brazg, Meghan Fahey, Carey L. Holleran, Mark Connolly, Jane Woodward, Patrick W. Hennessy, Brian D. Schmit, T. George Hornby

Biomedical Engineering Faculty Research and Publications

Background. Many physical interventions can improve locomotor function in individuals with motor incomplete spinal cord injury (iSCI), although the training parameters that maximize recovery are not clear. Previous studies in individuals with other neurologic injuries suggest the intensity of locomotor training (LT) may positively influence walking outcomes. However, the effects of intensity during training of individuals with iSCI have not been tested. Objective. The purpose of this pilot, blinded-assessor randomized trial was to evaluate the effects of LT intensity on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI >1 year duration performed either …

Pvdf-Trfe Electroactive Polymer Mechanical-To-Electrical Energy Harvesting Experimental Bimorph Structure, William G. Kaval, Robert A. Lake, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

Research of electrostrictive polymers has generated new opportunities for harvesting energy from the surrounding environment and converting it into usable electrical energy. Electroactive polymer (EAP) research is one of the new opportunities for harvesting energy from the natural environment and converting it into usable electrical energy. Piezoelectric ceramic based energy harvesting devices tend to be unsuitable for low-frequency mechanical excitations such as human movement. Organic polymers are typically softer and more flexible therefore translated electrical energy output is considerably higher under the same mechanical force. In addition, cantilever geometry is one of the most used structures in piezoelectric energy harvesters, …

H2−H∞ Control Of Continuous-Time Nonlinear Systems Using The State-Dependent Riccati Equation Approach, Xin Wang, Edwin E. Yaz, Susan C. Schneider, Yvonne I. Yaz

Electrical and Computer Engineering Faculty Research and Publications

This paper presents a novel state-dependent Riccati equation (SDRE) control approach with the purpose of providing a more effective control design framework for continuous-time nonlinear systems to achieve a mixed nonlinear quadratic regulator and H∞ control performance criteria. By solving the generalized SDRE, the optimal control solution is found to achieve mixed performance objectives guaranteeing nonlinear quadratic optimality with inherent stability property in combination with H∞ type of disturbance reduction. An efficient computational algorithm is given to find the solution to the SDRE. The efficacy of the proposed technique is used to design the control system for inverted …

H2−H∞ Control Of Discrete-Time Nonlinear Systems Using The State-Dependent Riccati Equation Approach, Xin Wang, Edwin E. Yaz, Susan C. Schneider, Yvonne I. Yaz

Electrical and Computer Engineering Faculty Research and Publications

A novel H₂−H_∞ State-dependent Riccati equation control approach is presented for providing a generalized control framework to discrete-time nonlinear system. By solving a generalized Riccati equation at each time step, the nonlinear state feedback control solution is found to satisfy mixed performance criteria guaranteeing quadratic optimality with inherent stability property in combination with H∞ type of disturbance attenuation. Two numerical techniques to compute the solution of the resulting Riccati equation are presented: The first one is based on finding the steady-state solution of the difference equation at every step and the second one is based on finding …

Mass Reduction Patterning Of Silicon-On-Oxide–Based Micromirrors, Harris J. Hall, Andrew Green, Sarah Dooley, Jason D. Schmidt, Lavern A. Starman, Derrick Langley, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

It has long been recognized in the design of micromirror-based optical systems that balancing static flatness of the mirror surface through structural design with the system’s mechanical dynamic response is challenging. Although a variety of mass reduction approaches have been presented in the literature to address this performance trade, there has been little quantifiable comparison reported. In this work, different mass reduction approaches, some unique to the work, are quantifiably compared with solid plate thinning in both curvature and mass using commercial finite element simulation of a specific square silicon-on-insulator–based micromirror geometry. Other important considerations for micromirror surfaces, including surface …

Multimodal Imaging Of Photoreceptor Structure In Choroideremia, Lynn W. Sun, Ryan D. Johnson, Vesper Williams, Phyllis Summerfelt, Alfredo Dubra, David V. Weinberg, Kimberly E. Stepien, Gerald A. Fishman, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose

Choroideremia is a progressive X-linked recessive dystrophy, characterized by degeneration of the retinal pigment epithelium (RPE), choroid, choriocapillaris, and photoreceptors. We examined photoreceptor structure in a series of subjects with choroideremia with particular attention to areas bordering atrophic lesions.

Methods

Twelve males with clinically-diagnosed choroideremia and confirmed hemizygous mutations in the CHM gene were examined. High-resolution images of the retina were obtained using spectral domain optical coherence tomography (SD-OCT) and both confocal and non-confocal split-detector adaptive optics scanning light ophthalmoscope (AOSLO) techniques.

Results

Eleven CHM gene mutations (3 novel) were identified; three subjects had the same mutation and one …

Triclosan: An Instructive Tale, Patrick J. Mcnamara, Stuart B. Levy

Civil and Environmental Engineering Faculty Research and Publications

The Food and Drug Administration (FDA) recently released a final rule to ban triclosan and 18 other antimicrobial chemicals from soaps. We applaud this rule specifically because of the associated risks that triclosan poses to the spread of antibiotic resistance throughout the environment. This persistent chemical constantly stresses bacteria to adapt, and behavior that promotes antibiotic resistance needs to be stopped immediately when the benefits are null.

Contact Phenomenon Of Free-Rolling Wide-Base Tires: Effect Of Speed And Temperature, Jaime Hernandez, Imad L. Al-Qadi

Civil and Environmental Engineering Faculty Research and Publications

The finite-element method was used to quantify the effect of temperature and speed on contact area, deflection, and three-dimensional contact stresses of a free-rolling wide-base tire. The tire model comprised material properties identified in the laboratory and/or provided by the tire manufacturer (hyperviscoelastic rubber and linear elastic reinforcement) and accurate geometry. The model was validated using measured deflection and contact area. The analysis matrix consisted of 81 cases resulting from a combination of three loads, tire-inflation pressures, speeds, and temperatures. Four criteria were used to compare contact stresses: range, average, root-mean-square error, and coefficient of determination. Speed and temperature influence …

Direct Quadrature Method Of Moments With Delumping For Modeling Multicomponent Droplet Vaporization, Simcha L. Singer

Mechanical Engineering Faculty Research and Publications

A multicomponent droplet vaporization model which combines the computational efficiency of continuous thermodynamic approaches with the detailed species information provided by discrete component models has been developed. The Direct Quadrature Method of Moments (DQMoM) is used to efficiently solve for the evolution of the nodes and weights of the equivalent liquid-phase mole fraction distribution without assuming any functional form. The novelty of the approach is an inexpensive delumping procedure that is used to reconstruct the time-dependent mole fractions and fluxes for all discrete species. When applied to a vaporizing kerosene droplet, agreement between the full discrete component model, which solves …

Repeat Exposure To Leg Swing Perturbations During Treadmill Training Induces Long-Term Retention Of Increased Step Length In Human Sci: A Pilot Randomized Controlled Study, Ming Wu, Jill M. Landry, Janis Kim, Brian D. Schmit, Sheng-Che Yen, Jillian Mcdonald, Yunhui Zhang

Biomedical Engineering Faculty Research and Publications

Objective: To determine whether repeat exposure to force perturbations during treadmill training can induce long-term retention of improved step length and overall improvements in locomotor function in persons with spinal cord injury.

Design: Fourteen patients with spinal cord injury were recruited and randomly assigned to swing resistance or swing assistance training groups. A controlled swing resistance or assistance force, for resistance or assistance training groups, respectively, was applied to both legs through a cable-driven robotic system during treadmill training. Each participant trained 3 times per week for 6 weeks. Step length, walking speed, 6-minute walking distance, and other clinical assessments …

Transient Local Bone Remodeling Effects Of Rhbmp-2 In An Ovine Interbody Spine Fusion Model, Hyun W. Bae, Vikas V. Patel, Zeeshan M. Sardar, Jeffrey Badura, Ben B. Pradhan, Howard Seim, Anthony S. Turner, Jeffrey M. Toth

Biomedical Engineering Faculty Research and Publications

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a powerful osteoinductive morphogen capable of stimulating the migration of mesenchymal stem cells (MSCs) to the site of implantation and inducing the proliferation and differentiation of these MSCs into osteoblasts. Vertebral end-plate and vertebral body resorption has been reported after interbody fusion with high doses of rhBMP-2. In this study, we investigated the effects of 2 rhBMP-2 doses on peri-implant bone resorption and bone remodeling at 7 time points in an end-plate-sparing ovine interbody fusion model. Methods: Twenty-one female sheep underwent an end-plate-sparing discectomy followed by interbody fusion at L2-L3 and L4-L5 …

Investigation Of Polymer–Plasticizer Blends As Sh-Saw Sensor Coatings For Detection Of Benzene In Water With High Sensitivity And Long-Term Stability, Pintu Adhikari, Laura Jeanne Alderson, Florian Bender, Antonio J. Ricco, Fabien Josse

Electrical and Computer Engineering Faculty Research and Publications

We report the first-ever direct detection of benzene in water at concentrations below 100 ppb (parts per billion) using acoustic wave (specifically, shear-horizontal surface acoustic wave, SH-SAW) sensors with plasticized polymer coatings. Two polymers and two plasticizers were studied as materials for sensor coatings. For each polymer–plasticizer combination, the influence of the mixing ratio of the blend on the sensitivity to benzene was measured and compared to commercially available polymers that were used for BTEX (benzene, toluene, ethylbenzene, and xylene) detection in previous work. After optimizing the coating parameters, the highest sensitivity and lowest detection limit for benzene were found …

Accuracy Of Patient-Specific Organ Dose Estimates Obtained Using An Automated Image Segmentation Algorithm, Taly Gilat-Schmidt, Adam S. Wang, Thomas Coradi, Benjamin Haas, Josh Star-Lack

Biomedical Engineering Faculty Research and Publications

The overall goal of this work is to develop a rapid, accurate, and automated software tool to estimate patient-specific organ doses from computed tomography (CT) scans using simulations to generate dose maps combined with automated segmentation algorithms. This work quantified the accuracy of organ dose estimates obtained by an automated segmentation algorithm. We hypothesized that the autosegmentation algorithm is sufficiently accurate to provide organ dose estimates, since small errors delineating organ boundaries will have minimal effect when computing mean organ dose. A leave-one-out validation study of the automated algorithm was performed with 20 head-neck CT scans expertly segmented into nine …

Pyrolysis Of Wastewater Biosolids Significantly Reduces Estrogenicity, T. C. Hoffman, Daniel Zitomer, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Most wastewater treatment processes are not specifically designed to remove micropollutants. Many micropollutants are hydrophobic so they remain in the biosolids and are discharged to the environment through land-application of biosolids. Micropollutants encompass a broad range of organic chemicals, including estrogenic compounds (natural and synthetic) that reside in the environment, a.k.a. environmental estrogens. Public concern over land application of biosolids stemming from the occurrence of micropollutants hampers the value of biosolids which are important to wastewater treatment plants as a valuable by-product. This research evaluated pyrolysis, the partial decomposition of organic material in an oxygen-deprived system under high temperatures, as …

Altered Antibiotic Tolerance In Anaerobic Digesters Acclimated To Triclosan Or Triclocarban, Daniel Elliott Carey, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Bench-scale anaerobic digesters were amended to elevated steady-state concentrations of triclosan (850 mg/kg) and triclocarban (150 mg/kg) using a synthetic feed. After more than 9 solids retention time (SRT) values of acclimatization, biomass from each digester (and a control digester that received no antimicrobials) was used to assess the toxicity of three antibiotics. Methane production rate was measured as a surrogate for activity in microcosms that received doses of antibiotics ranging from no-antibiotic to inhibitory concentrations. Biomass amended with triclocarban was more sensitive to tetracycline compared to the control indicating synergistic inhibitory effects between this antibiotic and triclocarban. In contrast, …

Anaerobic Digester Bioaugmentation Influences Quasi Steady State Performance And Microbial Community, Kaushik Venkiteshwaran, K. Milferstedt, J. Hamelin, Daniel Zitomer

Civil and Environmental Engineering Faculty Research and Publications

Nine anaerobic digesters, each seeded with biomass from a different source, were operated identically and their quasi steady state function was compared. Subsequently, digesters were bioaugmented with a methanogenic culture previously shown to increase specific methanogenic activity. Before bioaugmentation, different seed biomass resulted in different quasi steady state function, with digesters clustering into three groups distinguished by methane (CH₄) production. Digesters with similar functional performance contained similar archaeal communities based on clustering of Illumina sequence data of the V4V5 region of the 16S rRNA gene. High CH₄ production correlated with neutral pH and high Methanosarcina abundance, whereas …

Effect Of Surgical Fusion On Volitional Weight-Shifting In Individuals With Adolescent Idiopathic Scoliosis, Nikhil T. Kurapati, Joseph Krzak, Adam Graf, Sahar Hassani, Sergey Tarima, Peter F. Sturm, Kim W. Hammerberg, Purnendu Gupta, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Study Design

Prospective.

Objectives

The goals of this study were to (1) evaluate the differences in weightbearing symmetry between individuals with adolescent idiopathic scoliosis (AIS) and typically developing controls; (2) observe the effect of posterior spinal fusion and instrumentation (PSFI) on volitional weight-shifting at 1 and 2 years postoperatively; and (3) evaluate whether lowest instrumented fusion level (ie, lowest instrumented vertebra [LIV]) in PSFI has an effect on volitional weight-shifting.

Summary of Background Data

Previous studies have conflicting findings with regard to the effect of scoliosis on postural control tasks as well as the effect of surgery. They have also …

Smart Power Grid Synchronization With Fault Tolerant Nonlinear Estimation, Xin Wang, Edwin E. Yaz

Electrical and Computer Engineering Faculty Research and Publications

Effective real-time state estimation is essential for smart grid synchronization, as electricity demand continues to grow, and renewable energy resources increase their penetration into the grid. In order to provide a more reliable state estimation technique to address the problem of bad data in the PMU-based power synchronization, this paper presents a novel nonlinear estimation framework to dynamically track frequency, voltage magnitudes and phase angles. Instead of directly analyzing in abc coordinate frame, symmetrical component transformation is employed to separate the positive, negative, and zero sequence networks. Then, Clarke's transformation is used to transform the sequence networks into the αβ …

Saliency Ratio And Power Factor Of Ipm Motors Optimally Designed For High Efficiency And Low Cost Objectives, Peng Zhang, Dan M. Ionel, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

This paper uses formal mathematical optimization techniques based on parametric finite-element-based computationally efficient models and differential evolution algorithms. For constant-power applications, in the novel approach described, three concurrent objective functions are minimized: material cost, losses, in order to ensure high efficiency, and the difference between the rated and the characteristic current, aiming to achieve very high constant-power flux-weakening range. Only the first two objectives are considered for constant-torque applications. Two types of interior permanent magnet rotors in a single- and double-layer V-shaped configuration are considered, respectively. The stator has the typical two slots per pole and phase distributed winding configuration. …

Performance-Robust Dynamic Feedback Control Of Lipschitz Nonlinear Systems, Winston Baker

Dissertations (1934 -)

This dissertation addresses the dynamic control of nonlinear systems with finite energy noise in the state and measurement equations. Regional eigenvalue assignment (REA) is used to ensure that the state estimate error is driven to zero significantly faster than the state itself. Moreover, the controller is designed for the resulting closed loop system to achieve any one of a set of general performance criteria (GPC). The nonlinear model is assumed to have a Lipschitz nonlinearity both in the state and measurement equations. By using the norm bound of the nonlinearity, the controller is designed to be robust against all nonlinearities …

Parallel Reference Speaker Weighting For Kinematic-Independent Acoustic-To-Articulatory Inversion, An Ji, Michael T. Johnson, Jeffrey J. Berry

Speech Pathology and Audiology Faculty Research and Publications

Acoustic-to-articulatory inversion, the estimation of articulatory kinematics from an acoustic waveform, is a challenging but important problem. Accurate estimation of articulatory movements has the potential for significant impact on our understanding of speech production, on our capacity to assess and treat pathologies in a clinical setting, and on speech technologies such as computer aided pronunciation assessment and audio-video synthesis. However, because of the complex and speaker-specific relationship between articulation and acoustics, existing approaches for inversion do not generalize well across speakers. As acquiring speaker-specific kinematic data for training is not feasible in many practical applications, this remains an important and …

Modeling Pyrolysis Of Large Coal Particles With Many Species, Jianqing Li

Master's Theses (2009 -)

Coal currently supplies 40% of the world’s electricity needs, and is one of the most important energy sources. As the initial stage of coal combustion, pyrolysis is a thermal decomposition process which converts coal into light gases and tars, which are subsequently consumed in combustion reactions, as well as solid char. Recently there has been interest in using slow pyrolysis as a stand-alone process for the production of chemicals and fuels from large (mm-scale) coal particles. Simulations can be used to efficiently study the impact of pyrolysis conditions on gas, tar and char yields, as well as gas and tar …

High-Affinity Phosphate-Binding Protein (Pbp) For Phosphorous Recovery: Proof Of Concept Using Recombinant Escherichia Coli, Yu Yang, Wendy Ballent, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Phosphorus (P) is a critical, non-renewable nutrient; yet excess discharges can lead to eutrophication and deterioration of water quality. Thus, P removal from water must be coupled with P recovery to achieve sustainable P management. P-specific proteins provide a novel, promising approach to recover P from water. Bacterial phosphate-binding proteins (PBPs) are able to effectively remove phosphate, achieving extremely low levels in water (i.e. 0.015 mg-P L⁻¹). A prerequisite of using PBP for P recovery, however, is not only removal, but also controlled P release, which has not yet been reported. Phosphate release using recombinant PBP-expressing Escherichia coli …

Engineering Synthetic Feedback To Promote Recovery Of Self-Feeding Skills In People With Sensory Deficits Due To Stroke, Alexis Krueger

Master's Theses (2009 -)

Kinesthesia refers to sensations of limb position and movement, and deficits of upper limb kinesthetic feedback are common after stroke, impairing stroke survivors’ ability to perform the fundamental reaching and stabilization behaviors needed for daily functions like self-feeding. I attempt to mitigate the negative impact of post-stroke kinesthesia deficits by evaluating the utility of vibrotactile sensory substitution to restore closed-loop kinesthetic feedback of the upper limb. As a first step, this study evaluated performance in healthy individuals during fundamental reaching, stabilization, and tracking behaviors while using supplemental vibrotactile feedback encoding either limb state information or goal-aware error information. First, I …

Characterization Of Histological Changes In The Microvasculature Of Rat Skeletal Muscle After Spinal Cord Injury, Sally Lin

Master's Theses (2009 -)

The purpose of this study was to determine whether there are histological changes in the microvasculature of rat skeletal muscle following chronic spinal cord injury both above and below the level of injury. This study is important because microvascular structure likely impacts muscle performance and cardiovascular health. To the best of our knowledge, this is the only study to investigate microvascular structure within rat skeletal muscle after spinal cord injury. We hypothesized structural remodeling would occur in both the myofibers and microvasculature, which would then manifest in differences in myofiber cross sectional area and microvascular diameter, wall thickness, wall to …

Optimization Of The Bowtie Gap Geometry For A Maximum Electric Field Enhancement, Tsenguun Byambadorj

Master's Theses (2009 -)

Optimization of the geometry of a metallic bowtie gap at radio frequency is presented in this thesis. Since the design and fabrication of a plasmonic device (nanogap) at nanoscale is challenging, the results of this study can be used to estimate the best design parameters for nanogap structure. The geometry of the bowtie gap including gap size, tip width, metal thickness, and tip angle are investigated at macroscale to find the maximum electric field enhancement across the gap. This thesis focuses on the simulation portion of a work that consists of experimental and simulation platforms. The simulation platform is created …

Evaluation Of An Actuated Wrist Orthosis For Use In Assistive Upper Extremity Rehabilitation, Devon Holley

Master's Theses (2009 -)

Cerebral palsy (CP) is a neurological condition caused by damage to motor control centers of the brain. This leads to physical and cognitive deficiencies that can reduce an individual’s quality of life. Specifically, motor deficiencies of the upper extremity can make it difficult for an individual to complete everyday tasks, including eating, drinking, getting dressed, or combing their hair. Physical therapy, involving repetitive tasks, has been shown to be effective in training normal motion of the limb by invoking the neuroplasticity of the brain and its ability to adapt in order to facilitate motor learning. Creating a device for use …