Engineering Commons^™

Rupture To Rafters To Response: Completing The Loop Of Earthquake Science, Engineering And Policy, Ting Lin

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Isoflurane Modulates Cardiac Mitochondrial Bioenergetics By Selectively Attenuating Respiratory Complexes, Bhawana Agarwal, Ranjan K. Dash, David F. Stowe, Zeljko J. Bosnjak, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

Mitochondrial dysfunction contributes to cardiac ischemia–reperfusion (IR) injury but volatile anesthetics (VA) may alter mitochondrial function to trigger cardioprotection. We hypothesized that the VA isoflurane (ISO) mediates cardioprotection in part by altering the function of several respiratory and transport proteins involved in oxidative phosphorylation (OxPhos). To test this we used fluorescence spectrophotometry to measure the effects of ISO (0, 0.5, 1, 2 mM) on the time-course of interlinked mitochondrial bioenergetic variables during states 2, 3 and 4 respiration in the presence of either complex I substrate K⁺-pyruvate/malate (PM) or complex II substrate K⁺-succinate (SUC) at physiological …

Diffuse Reflectance Spectroscopy Of Epithelial Tissue With A Smart Fiber-Optic Probe, Bing Yu, Amy Shah, Vivek K. Nagarajan, Daron G. Ferris

Biomedical Engineering Faculty Research and Publications

Diffuse reflectance spectroscopy (DRS) with a fiber-optic probe can noninvasively quantify the optical properties of epithelial tissues and has shown the potential as a cost-effective, fast and sensitive tool for diagnosis of early precancerous changes in the cervix and oral cavity. However, current DRS systems are susceptible to several sources of systematic and random errors, such as uncontrolled probe-to-tissue pressure and lack of a real-time calibration that can significantly impair the measurement accuracy, reliability and validity of this technology as well as its clinical utility. In addition, such systems use bulky, high power and expensive optical components which impede their …

Classification Of Human Retinal Microaneurysms Using Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography, Michael Dubow, Alexander Pinhas, Nishit Shah, Robert F. Cooper, Alexander Gan, Ronald C. Gentile, Vernon Hendrix, Yusufu N. Sulai, Joseph Carroll, Toco Y.P. Chui, Joseph B. Walsh, Rishard Weitz, Alfredo Dubra, Richard B. Rosen

Biomedical Engineering Faculty Research and Publications

Purpose.

Microaneurysms (MAs) are considered a hallmark of retinal vascular disease, yet what little is known about them is mostly based upon histology, not clinical observation. Here, we use the recently developed adaptive optics scanning light ophthalmoscope (AOSLO) fluorescein angiography (FA) to image human MAs in vivo and to expand on previously described MA morphologic classification schemes.

Methods.

Patients with vascular retinopathies (diabetic, hypertensive, and branch and central retinal vein occlusion) were imaged with reflectance AOSLO and AOSLO FA. Ninety-three MAs, from 14 eyes, were imaged and classified according to appearance into six morphologic groups: focal bulge, saccular, fusiform, mixed, …

Comparison Of Adaptive Optics Scanning Light Ophthalmoscopic Fluorescein Angiography And Offset Pinhole Imaging, Toco Y.P. Chui, Michael Dubow, Alexander Pinhas, Nishit Shah, Alexander Gan, Rishard Weitz, Yusufu N. Sulai, Alfredo Dubra, Richard B. Rosen

Biomedical Engineering Faculty Research and Publications

Recent advances to the adaptive optics scanning light ophthalmoscope (AOSLO) have enabled finer in vivo assessment of the human retinal microvasculature. AOSLO confocal reflectance imaging has been coupled with oral fluorescein angiography (FA), enabling simultaneous acquisition of structural and perfusion images. AOSLO offset pinhole (OP) imaging combined with motion contrast post-processing techniques, are able to create a similar set of structural and perfusion images without the use of exogenous contrast agent. In this study, we evaluate the similarities and differences of the structural and perfusion images obtained by either method, in healthy control subjects and in patients with retinal vasculopathy …

Proposal Of Vibrionimonas Magnilacihabitans Gen. Nov., Sp. Nov., A Curved Gram Negative Bacterium Isolated From Lake Michigan Water, Richard A. Albert, Daniel Zitomer, Michael Dollhopf, Anne Schauer-Gimenez, Craig Struble, Michael King, Sona Son, Stefan Langer, Hans-Jürgen Busse

Civil and Environmental Engineering Faculty Research and Publications

A mesophilic bacterium appearing as curved rod-shaped cells was isolated from Lake Michigan water. It exhibited highest similarities with Sediminibacterium ginsengisoli DCY13^T (94.4 %); Sediminibacterium salmoneum NJ-44^T (93.6 %) and Hydrotalea flava CCUG 51397 ^T (93.1 %) while similarities with other recognized species were sym-homospermidine was the primary polyamine. The major cellular fatty acids were iso-C_15 : 1G, iso-C_15 : 0, iso-C_16 : 0 3-OH and iso-C_17 : 0 3-OH, with moderate amounts of iso-C_16 : 0. The presence of glycolipids differentiated the novel strains from related genera. The DNA …

A Lensing Effect Of Inner Retinal Cysts On Images Of The Photoreceptor Mosaic, Christopher S. Langlo, John A. Flatter, Alfredo Dubra, William J. Wirostko, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Speech Enhancement Using Bayesian Estimators Of The Perceptually-Motivated Short-Time Spectral Amplitude (Stsa) With Chi Speech Priors, Marek B. Trawicki, Michael T. Johnson

Electrical and Computer Engineering Faculty Research and Publications

In this paper, the authors propose new perceptually-motivated Weighted Euclidean (WE) and Weighted Cosh (WCOSH) estimators that utilize more appropriate Chi statistical models for the speech prior with Gaussian statistical models for the noise likelihood. Whereas the perceptually-motivated WE and WCOSH cost functions emphasized spectral valleys rather than spectral peaks (formants) and indirectly accounted for auditory masking effects, the incorporation of the Chi distribution statistical models demonstrated distinct improvement over the Rayleigh statistical models for the speech prior. The estimators incorporate both weighting law and shape parameters on the cost functions and distributions. Performance is evaluated in terms of the …

On The Use Of Gaussian Approximation In Analyzing The Performance Of Optical Receivers, George El-Howayek, C. Zhang, Y. Li, J. S. Ng, J. P.R. David, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

The analytical calculation of the bit error rate (BER) of digital optical receivers that employ avalanche photodiodes (APDs) is challenging due to 1) the stochastic nature of the avalanche photodiode's impulse-response function and 2) the presence of intersymbol interference (ISI). At ultrafast transmission rates, ISI becomes a dominant component of the BER, and its effect on the BER should be carefully addressed. One solution to this problem, termed the bit-pattern-dependent (PD) approach, is to first calculate the conditional BER given a specific bit pattern and then average over all possible bit patterns. Alternatively, a simplifying method, termed the bit-pattern-independent (PI) …

Biomechanical Model For Evaluation Of Pediatric Upper Extremity Joint Dynamics During Wheelchair Mobility, Alyssa J. Schnorenberg, Brooke A. Slavens, Mei Wang, Lawrence Vogel, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Pediatric manual wheelchair users (MWU) require high joint demands on their upper extremity (UE) during wheelchair mobility, leading them to be at risk of developing pain and pathology. Studies have examined UE biomechanics during wheelchair mobility in the adult population; however, current methods for evaluating UE joint dynamics of pediatric MWU are limited. An inverse dynamics model is proposed to characterize three-dimensional UE joint kinematics and kinetics during pediatric wheelchair mobility using a SmartWheel instrumented handrim system. The bilateral model comprises thorax, clavicle, scapula, upper arm, forearm, and hand segments and includes the sternoclavicular, acromioclavicular, glenohumeral, elbow and wrist joints. …

Utilization Of Simulated Ground Motions For Engineering Performance Assessment Of Tall Buildings, Nenad Bijelic, Ting Lin, Gregory Deierlein

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Development Of High Fidelity Soot Aerosol Dynamics Models Using Method Of Moments With Interpolative Closure, Somesh Roy, P. G. Arias, Vivien R. Lecoustre, Daniel C. Haworth, H. G. Im, Arnaud Trouvé

Mechanical Engineering Faculty Research and Publications

The method of moments with interpolative closure (MOMIC) for soot formation and growth provides a detailed modeling framework maintaining a good balance in generality, accuracy, robustness, and computational efficiency. This study presents several computational issues in the development and implementation of the MOMIC-based soot modeling for direct numerical simulations (DNS). The issues of concern include a wide dynamic range of numbers, choice of normalization, high effective Schmidt number of soot particles, and realizability of the soot particle size distribution function (PSDF). These problems are not unique to DNS, but they are often exacerbated by the high-order numerical schemes used in …

Development Of Low Cost Piezoresistive Organic Cantilever Resonator, D. Thuau, Cedric Ayela, E. Lemaire, Stephen M. Heinrich, P. Poulin, I. Dufour

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

End Mass Effects On The Frequency Response Of Cantilevers: Analytical Results, Stephen M. Heinrich, Isabelle Dufour

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Methyl Coenzyme M Reductase (Mcra) Gene Abundance Correlates With Activity Measurements Of Methanogenic H2/Co2-Enriched Anaerobic Biomass, Rachel Morris, Anne Schauer-Gimenez, Ujwal H. Bhattad, Colleen Kearney, Craig Struble, Daniel Zitomer, James Maki

Civil and Environmental Engineering Faculty Research and Publications

Biologically produced methane (CH₄) from anaerobic digesters is a renewable alternative to fossil fuels, but digester failure can be a serious problem. Monitoring the microbial community within the digester could provide valuable information about process stability because this technology is dependent upon the metabolic processes of microorganisms. A healthy methanogenic community is critical for digester function and CH₄ production. Methanogens can be surveyed and monitored using genes and transcripts of mcrA, which encodes the α subunit of methyl coenzyme M reductase – the enzyme that catalyses the final step in methanogenesis. Using clone libraries and quantitative …

Development Of Analytical Models Of T- And U-Shaped Cantilever-Based Mems Devices For Sensing And Energy Harvesting Applications, Stephen M. Heinrich, M. T. Boudjiet, D. Thuau, P. Poulin, C. Ayela, Isabelle Dufour

Civil and Environmental Engineering Faculty Research and Publications

Dynamic-mode cantilever-based structures supporting end masses are frequently used as MEMS/NEMS devices in application areas as diverse as chemical/biosensing, atomic force microscopy, and energy harvesting. This paper presents a new analytical solution for the free vibration of a cantilever with a rigid end mass of finite size. The effects of both translational and rotational inertia as well as horizontal eccentricity of the end mass are incorporated into the model. This model is general regarding the end-mass distribution/geometry and is validated here for the commonly encountered geometries of T- and U-shaped cantilevers. Comparisons with 3D FEA simulations and experiments on silicon …

Lateral-Mode Vibration Of Microcantilever-Based Sensors In Viscous Fluids Using Timoshenko Beam Theory, Joshua Schultz, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

To more accurately model microcantilever resonant behavior in liquids and to improve lateral-mode sensor performance, a new model is developed to incorporate viscous fluid effects and Timoshenko beam effects (shear deformation, rotatory inertia). The model is motivated by studies showing that the most promising geometries for lateral-mode sensing are those for which Timoshenko effects are most pronounced. Analytical solutions for beam response due to harmonic tip force and electrothermal loadings are expressed in terms of total and bending displacements, which correspond to laser and piezoresistive readouts, respectively. The influence of shear deformation, rotatory inertia, fluid properties, and actuation/detection schemes on …

Dynamic Aspects Of Articulating With A Virtual Vocal Tract In Dysarthria, Jeffrey J. Berry, Cassandra North, Michael T. Johnson

Speech Pathology and Audiology Faculty Research and Publications

No abstract provided.

A Multi-Modal Continuous-Systems Model Of A Novel High-Q Disk Resonator In A Viscous Liquid, Mohamad S. Sotoudegan, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Impedance Control And Internal Model Formation When Reaching In A Randomly Varying Dynamical Environment, C. D. Takahashi, Robert A. Scheidt, D. J. Reikensmeyer

Biomedical Engineering Faculty Research and Publications

We investigated the effects of trial-to-trial, random variation in environmental forces on the motor adaptation of human subjects during reaching. Novel sequences of dynamic environments were applied to subjects' hands by a robot. Subjects reached first in a “mean field” having a constant gain relating force and velocity, then in a “noise field,” having a gain that varied randomly between reaches according to a normal distribution with a mean identical to that of the mean field. The unpredictable nature of the noise field did not degrade adaptation as quantified by final kinematic error and rate of adaptation. To achieve this …

Bone Material Properties In Osteogenesis Imperfecta: A Matter Of Quantity Over Quality, Carolyne Albert, John Jameson, Gerald F. Harris, Peter Smith

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Emerging Optical Techniques For Detection Of Oral, Cervical And Anal Cancer In Low-Resource Settings, Bing Yu, Daron G. Ferris, Yang Liu, Vivek K. Nagarajan

Biomedical Engineering Faculty Research and Publications

Cancers of the oral and anogenital regions are a growing global health problem that disproportionately impact women and men living in developing countries. The high death rate in developing countries is largely due to the fact that these countries do not have the appropriate medical infrastructure and resources to support the organized screening and diagnostic programs that are available in the developed world. Emerging optical diagnostics techniques, such as optical spectroscopy, reflectance imaging, and fluorescence imaging, are noninvasive techniques that are sensitive to multiple cancer biomarkers and have shown the potential as a cost–effective and fast tool for diagnosis of …

Simultaneous Robotic Manipulation And Functional Magnetic Resonance Imaging: Feasibility In Children With Autism Spectrum Disorders, Nicole Marie Gregor Salowitz, Bridget K. Dolan, Rheanna Remmel, Amy V. Van Hecke, Kristine M. Mosier, Lucia S. Simo, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

An unanswered question concerning the neural basis of autism spectrum disorders (ASD) is how sensorimotor deficits in individuals with ASD are related to abnormalities of brain function. We previously described a robotic joystick and video game system that allows us to record functional magnetic resonance images (FMRI) while adult humans make goal- directed wrist motions. We anticipated several challenges in extending this approach to studying goal-directed behaviors in children with ASD and in typically developing (TYP) children. In particular we were concerned that children with autism may express increased levels of anxiety as compared to typically developing children due to …

Timoshenko Beam Model For Lateral Vibration Of Liquid-Phase Microcantilever-Based Sensors, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

Dynamic-mode microcantilever-based devices are potentially well suited to biological and chemical sensing applications. However, when these applications involve liquid-phase detection, fluid-induced dissipative forces can significantly impair device performance. Recent experimental and analytical research has shown that higher in-fluid quality factors (Q) are achieved by exciting microcantilevers in the lateral flexural mode. However, experimental results show that, for microcantilevers having larger width-to-length ratios, the behaviors predicted by current analytical models differ from measurements. To more accurately model microcantilever resonant behavior in viscous fluids and to improve understanding of lateral-mode sensor performance, a new analytical model is developed, incorporating both …

Virtual Capstone Design Teams: Preparing For Global Innovation (Conference Proceeding), Jay R. Goldberg, Susannah Howe

Biomedical Engineering Faculty Research and Publications

Global innovation requires collaboration between groups of people located in different parts of the world, and is a growing trend in industry. Virtual teams are often used to manage new product development projects. These teams are similar to traditional teams but are geographically separated and rely heavily on virtual methods of communication (email, Skype, teleconferencing, etc.) instead of regular face-to-face meetings. Experience working as a member of a virtual capstone design team can help prepare students for this growing trend. To begin preparing students for work on virtual teams in industry, we co-advised two virtual capstone design projects with students …

A North American Consortium On Rehabilitation Engineering And Technology For The Individual, Barbara Silver-Thorn, Jessica Lothman, Terence Miller

Biomedical Engineering Faculty Research and Publications

The availability and accessibility of appropriate rehabilitative healthcare, medical technology and treatment is an important national and international issue of particular relevance due to recent national healthcare reform initiatives. The focus of this project was to increase global competencies and awareness among biomedical engineers of the differing rehabilitative healthcare needs in North America via student exchange with consortium institutions in the U.S., Canada and Mexico. The aim was to increase understanding of alternative healthcare delivery systems with respect to technology and interaction with diverse client populations in a clinical setting and to enhance the development and technology transfer of new …

Plastic Deformation Investigation Of High Energy Input Friction, Tao Yan

Dissertations (1934 -)

In this dissertation, plastic deformation of friction surfaces under high energy input is investigated. The plastic deformation of the friction surface and subsurface was studied and models were established to estimate deformation.

In order to calculate the plastic deformation at friction surface, an algorithm based on Ramberg-Osgood relationship was generated, and a single material model was developed based on this algorithm. Work hardening caused by plastic deformation and thermal softening caused by elevated temperature were considered in the model. To validate the model, an apparatus was designed to perform friction tests under different conditions. A special steel specimen with a …

Non-Local Model For The Spatial Distribution Of Impact Ionization Events In Avalanche Photodiodes, David A. Ramirez, Majeed M. Hayat, Andrew S. Huntington, George M. Williams

Electrical and Computer Engineering Faculty Research and Publications

We report an extension of the analytical dead space multiplication theory that provides the means to theoretically determine the spatial distribution of electron and hole impact-ionization events in an arbitrarily specified heterojunction multiplication region. The model can be used to understand the role of the dead space in regularizing the locations of impact ionization. It can also be utilized to analyze, design, and optimize new generations of ultra-low noise, multistaged gain avalanche photodiodes based upon judiciously energizing and relaxing carriers to enhance electron impact ionization and suppress hole impact ionization.

Robust And Resilient State-Dependent Control Of Continuous-Time Nonlinear Systems With General Performance Criteria, Xin Wang, Edwin E. Yaz, James Long

Electrical and Computer Engineering Faculty Research and Publications

A novel state-dependent control approach for continuous-time nonlinear systems with general performance criteria is presented in this paper. This controller is optimally robust for model uncertainties and resilient against control feedback gain perturbations in achieving general performance criteria to secure quadratic optimality with inherent asymptotic stability property together with quadratic dissipative type of disturbance reduction. For the system model, unstructured uncertainty description is assumed, which incorporates commonly used types of uncertainties, such as norm-bounded and positive real uncertainties as special cases. By solving a state-dependent linear matrix inequality at each time, sufficient condition for the control solution can be found …

Age-Related Differentiation Of Sensorimotor Control Strategies During Pursuit And Compensatory Tracking, Megan L. Heenan, Robert A. Scheidt, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

Motor control deficits during aging have been well-documented. Various causes of neuromotor decline, including both peripheral and central neurological deficits, have been hypothesized. Here, we use a model of closed-loop sensorimotor control to examine the functional causes of motor control deficits during aging. We recruited 14 subjects aged 19-61 years old to participate in a study in which they performed single-joint compensatory and pursuit tracking tasks with their dominant hand. We found that visual response delay and visual noise increased with age, while reliance on visual feedback, especially during compensatory tracking decreased. Increases in visual noise were also positively correlated …