Engineering Commons^™

A Novel Batch-Processing Method For Accurate Crystallographic Axis Alignment, Jun Hyun Han, Shankar Radhakrishnan, Chung-Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

A new method for the accurate alignment of lithographically-defined patterns to the crystallographic axes of substrates is presented. We provide a lower (worst-case) limit of the achievable high aspect ratio using anisotropic wet chemical silicon etch for deep trenches. The method uses the fact that the intensity of light reflected from two sets of gratings, one on the photomask and the other on the substrate, is a sharp function of their relative angular misalignment. By using pre-etched gratings on the substrate formed by wet anisotropic etching, alignment accuracies better than 50 millidegrees with respect to silicon crystallographic axes have been …

Conditional Spectrum Computation Incorporating Multiple Causal Earthquakes And Ground‐Motion Prediction Models, Ting Lin, Stephen C. Harmsen, Jack W. Baker, Nicolas Luco

Civil and Environmental Engineering Faculty Research and Publications

The Conditional Spectrum (CS) is a target spectrum (with conditional mean and conditional standard deviation) that links seismic hazard information with ground motion selection for nonlinear dynamic analysis. Probabilistic seismic hazard analysis (PSHA) estimates the ground motion hazard by incorporating the aleatory uncertainties in all earthquake scenarios and resulting ground motions as well as the epistemic uncertainties in ground motion prediction models (GMPMs) and seismic source models. Typical CS calculations to date are produced for a single earthquake scenario using a single GMPM, but more precise use requires consideration of at least multiple causal earthquakes and multiple GMPMs that are …

Separation Of Visual And Motor Workspaces During Targeted Reaching Results In Limited Generalization Of Visuomotor Adaptation, Yuming Lei, Michelle J. Johnson, Jinsung Wang

Biomedical Engineering Faculty Research and Publications

Separating visual and proprioceptive information in terms of workspace locations during reaching movement has been shown to disturb transfer of visuomotor adaptation across the arms. Here, we investigated whether separating visual and motor workspaces would also disturb generalization of visuomotor adaptation across movement conditions within the same arm. Subjects were divided into four experimental groups (plus three control groups). The first two groups adapted to a visual rotation under a “dissociation” condition in which the targets for reaching movement were presented in midline while their arm performed reaching movement laterally. Following that, they were tested in an “association” condition in …

Wavelength Optimization For Quantitative Spectral Imaging Of Breast Tumor Margins, Justin Y. Lo, J. Quincy Brown, Sulochana Dhar, Bing Yu, Gregory M. Palmer, Nan M. Jokerst, Nirmala Ramanujam

Biomedical Engineering Faculty Research and Publications

A wavelength selection method that combines an inverse Monte Carlo model of reflectance and a genetic algorithm for global optimization was developed for the application of spectral imaging of breast tumor margins. The selection of wavelengths impacts system design in cost, size, and accuracy of tissue quantitation. The minimum number of wavelengths required for the accurate quantitation of tissue optical properties is 8, with diminishing gains for additional wavelengths. The resulting wavelength choices for the specific probe geometry used for the breast tumor margin spectral imaging application were tested in an independent pathology-confirmed ex vivo breast tissue data set and …

Field Experience As The Centerpiece Of An Integrated Model For Stem Teacher Preparation, Leigh A. Van Den Kieboom, Jill Mcnew-Birren, Ellen Eckman, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

The purpose of this study was to provide a descriptive account of one pathway for preparing high-quality STEM (science, technology, engineering, and mathematics) teachers for work in high-need urban schools. In this account, we discuss the supports that STEM majors need in learning how to think about the content that they know well, through an educational perspective that focuses on teaching and learning. We also describe the approach that we use that integrates content knowledge, pedagogical content knowledge, and three extensive teaching co-op experiences to facilitate the transition from successful STEM undergraduate students to effective teachers of STEM content. We …

Brief Report: Visuo-Spatial Guidance Of Movement During Gesture Imitation And Mirror Drawing In Children With Autism Spectrum Disorders, Nicole M.G. Salowitz, Petra Eccarius, Audrey Meyer Carson, Kirsten A. Schohl, Sheryl Jayne Stevens, Amy Vaughan Van Hecke, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Thirteen autistic and 14 typically developing children (controls) imitated hand/arm gestures and performed mirror drawing; both tasks assessed ability to reorganize the relationship between spatial goals and the motor commands needed to acquire them. During imitation, children with autism were less accurate than controls in replicating hand shape, hand orientation, and number of constituent limb movements. During shape tracing, children with autism performed accurately with direct visual feedback, but when viewing their hand in a mirror, some children with autism generated fewer errors than controls whereas others performed much worse. Large mirror drawing errors correlated with hand orientation and hand …

Surface Fluorescence Studies Of Tissue Mitochondrial Redox State In Isolated Perfused Rat Lungs, Kevin Staniszewski, Said H. Audi, Reyhaneh Sepehr, Elizabeth R. Jacobs, Mahsa Ranji

Biomedical Engineering Faculty Research and Publications

We designed a fiber-optic-based optoelectronic fluorometer to measure emitted fluorescence from the auto-fluorescent electron carriers NADH and FAD of the mitochondrial electron transport chain (ETC). The ratio of NADH to FAD is called the redox ratio (RR = NADH/FAD) and is an indicator of the oxidoreductive state of tissue. We evaluated the fluorometer by measuring the fluorescence intensities of NADH and FAD at the surface of isolated, perfused rat lungs. Alterations of lung mitochondrial metabolic state were achieved by the addition of rotenone (complex I inhibitor), potassium cyanide (KCN, complex IV inhibitor) and/or pentachlorophenol (PCP, uncoupler) into the perfusate recirculating …

Using Micro-Raman Spectroscopy To Assess Mems Si/Sio2 Membranes Exhibiting Negative Spring Constant Behavior, Lavern A. Starman, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

We introduce a novel micro-mechanical structure that exhibits two regions of stable linear positive and negative stiffness. Springs, cantilevers, beams and any other geometry that display an increasing return force that is proportional to the displacement can be considered to have a “Hookean” positive spring constant, or stiffness. Less well known is the opposite characteristic of a reducing return force for a given deflection, or negative stiffness. Unfortunately many simple negative stiffness structures exhibit unstable buckling and require additional moving components during deflection to avoid deforming out of its useful shape. In Micro-Electro-Mechanical Systems (MEMS) devices, buckling caused by stress …

Discrimination Of Photon- And Dark-Initiated Signals In Multiple Gain Stage Apd Photoreceivers, George M. Williams, David A. Ramirez, Majeed M. Hayat, Andrew S. Huntington

Electrical and Computer Engineering Faculty Research and Publications

We demonstrate the ability of linear mode single carrier multiplication (SCM) avalanche photodiode (APD)-based optical receivers to discriminate single-photon-initiated avalanche events from dark-current-initiated events. Because of their random spatial origin in discrete regions of the depletion region, in the SCM APD the dark-generated carriers multiply differently than the photon-generated carriers. This causes different count distributions and necessitates different statistical descriptions of the signal contributions from photon- and dark-originating impulse responses. To include dark carriers in the performance models of the SCM APD, we considered the influence of the spatial origin of the ionization chains on a receiver's noise performance over …

Development Of The Chinese Construction Industry After The Cultural Revolution: Administration Framework, Economic Growth, And Market Structure, Yilei Huang, Yi Lan, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

This paper presents the results of an investigation on the development of the Chinese construction industry after the Cultural Revolution in terms of administration framework, economic growth, and market structure, with the consideration of Chinese currency inflation. The development was divided into three stages based on Chinese government policy changes on the construction industry. In each stage, the reform of administration framework was reviewed, and the market size and market structure in both the domestic and the international markets were analyzed. Value added and gross output value of domestic market, the number of contracts, contracting value, total turnover, and turnover …

Mitochondrial Handling Of Excess Ca2+ Is Substrate-Dependent With Implications For Reactive Oxygen Species Generation, Mohammed Aldakkak, David F. Stowe, Ranjan K. Dash, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

The mitochondrial electron transport chain is the major source of reactive oxygen species (ROS) during cardiac ischemia. Several mechanisms modulate ROS production; one is mitochondrial Ca²⁺ uptake. Here we sought to elucidate the effects of extramitochondrial Ca²⁺ (e[Ca²⁺]) on ROS production (measured as H₂O₂ release) from complexes I and III. Mitochondria isolated from guinea pig hearts were preincubated with increasing concentrations of CaCl₂ and then energized with the complex I substrate Na⁺ pyruvate or the complex II substrate Na⁺ succinate. Mitochondrial H₂O₂ release rates were assessed after …

Discrimination Of Individual Tigers (Panthera Tigris) From Long Distance Roars, An Ji, Michael T. Johnson, Edward J. Walsh, Joann Mcgee, Douglas L. Armstrong

Electrical and Computer Engineering Faculty Research and Publications

This paper investigates the extent of tiger (Panthera tigris) vocal individuality through both qualitative and quantitative approaches using long distance roars from six individual tigers at Omaha's Henry Doorly Zoo in Omaha, NE. The framework for comparison across individuals includes statistical and discriminant function analysis across whole vocalization measures and statistical pattern classification using a hidden Markov model (HMM) with frame-based spectral features comprised of Greenwood frequency cepstral coefficients. Individual discrimination accuracy is evaluated as a function of spectral model complexity, represented by the number of mixtures in the underlying Gaussian mixture model (GMM), and temporal model complexity, …

Fatigue Risks In The Connections Of Sign Support Structures, Christopher M. Foley, Joseph A. Diekfuss, Baolin Wan

Transportation Reports with the Wisconsin Department of Transportation

This research effort develops a reliability-based approach for prescribing inspection intervals for mast-arm sign support structures corresponding to user-specified levels of fatigue-induced fracture risk. The resulting level of risk for a particular structure is dependent upon its geographical location, the type of connection it contains, the orientation of its mast-arm relative to north and the number of years it has been in service. The results of this research effort indicate that implementation of state-of-the-art reliability-based assessment procedures can contribute very valuable procedures for assigning inspection protocols (i.e. inspection intervals) that are based upon probabilities of finding fatigue-induced cracking in these …

Computational Fluid Dynamic Simulations For Determination Of Ventricular Workload In Aortic Arch Obstructions, Jessica S. Coogan, Frandics P. Chan, John F. Ladisa, Charles A. Taylor, Frank L. Hanley, Jeffrey A. Feinstein

Biomedical Engineering Faculty Research and Publications

Objective

The cardiac workload associated with various types of aortic obstruction was determined using computational fluid dynamic simulations.

Methods

Computed tomography image data were collected from 4 patients with 4 distinct types of aortic arch obstructions and 4 controls. The categorization of arch hypoplasia corresponded to the “A, B, C” nomenclature of arch interruption; a type “D” was added to represent diffuse arch hypoplasia. Measurements of the vessel diameter were compared against the normal measurements to determine the degree of narrowing. Three-dimensional models were created for each patient, and additional models were created for type A and B hypoplasia to …

Multi-Gain-Stage Ingaas Avalanche Photodiode With Enhanced Gain And Reduced Excess Noise, George M. Williams, Madison Compton, David A. Ramirez, Majeed M. Hayat, Andrew S. Huntington

Electrical and Computer Engineering Faculty Research and Publications

We report the design, fabrication, and test of an InGaAs avalanche photodiode (APD) for 950-1650 nm wavelength sensing applications. The APD is grown by molecular beam epitaxy on InP substrates from lattice-matched InGaAs and InAlAs alloys. Avalanche multiplication inside the APD occurs in a series of asymmetric gain stages whose layer ordering acts to enhance the rate of electron-initiated impact ionization and to suppress the rate of hole-initiated ionization when operated at low gain. The multiplication stages are cascaded in series, interposed with carrier relaxation layers in which the electric field is low, preventing avalanche feedback between stages. These measures …

Effect Of Fine Wire Electrode Insertion On Gait Patterns In Children With Hemiplegic Cerebral Palsy, Joseph Krzak, Daniel M. Corcos, Adam Graf, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Fine wire electromyography (EMG) is commonly used for surgical decision making in equinovarus foot deformity. However, this invasive technique may have the unwanted effect of altering the gait of children with cerebral palsy (CP). The purpose of this study was to determine if fine wire insertion into the posterior tibialis muscle affects temporal-spatial parameters and hindfoot kinematics during gait in children with equinovarus secondary to hemiplegic CP.

Methods

12 children with hemiplegic CP who presented with an equinovarus foot (mean age 12.5 yrs, four right-sided, eight left-sided) were recruited. Temporal-spatial parameters and 3-D segmental foot and ankle kinematic gait …

Long-Term Follow Up Of Van Nes Rotationplasty For Congenital Proximal Focal Femoral Deficiency, Jeffrey D. Ackman, Haluk Altiok, Ann Flanagan, Mary Peer, Adam Graf, Joseph Krzak, Sahar Hassani, Dan C. Eastwood, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Van Nes rotationplasty may be used for patients with congenital proximal focal femoral deficiency (PFFD). The lower limb is rotated to use the ankle and foot as a functional knee joint within a prosthesis. A small series of cases was investigated to determine the long-term outcome. At a mean of 21.5 years (11 to 45) after their rotationplasty, a total of 12 prosthetic patients completed the Short-Form (SF)-36, Faces Pain Scale-Revised, Harris hip score, Oswestry back pain score and Prosthetic Evaluation Questionnaires, as did 12 age- and gender-matched normal control participants. A physical examination and gait analysis, computerised dynamic posturography …

Protection Against Cardiac Injury By Small Ca2 +-Sensitive K+ Channels Identified In Guinea Pig Cardiac Inner Mitochondrial Membrane, David F. Stowe, Ashish K. Gadicherla, Yifan Zhou, Mohammed Aldakkak, Qunli Cheng, Wai-Meng Kwok, Ming Tao Jiang, James S. Heisner, Meiying Yang, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

We tested if small conductance, Ca^{2 +}‐sensitive K⁺ channels (SK_Ca) precondition hearts against ischemia reperfusion (IR) injury by improving mitochondrial (m) bioenergetics, if O₂‐derived free radicals are required to initiate protection via SK_Ca channels, and, importantly, if SK_Ca channels are present in cardiac cell inner mitochondrial membrane (IMM). NADH and FAD, superoxide (O₂⁻), and m[Ca^{2 +}] were measured in guinea pig isolated hearts by fluorescence spectrophotometry. SK_Ca and IK_Ca channel opener DCEBIO (DCEB) was given for 10 min and ended 20 min before IR. …

A New Look At Azimuthal Wave Propagation Constants Of An N-Layered Dielectric Coated Pec Cylinder, Jason V. Paul, Peter J. Collins, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

A method for determining the azimuthal wave propagation constants supported by an n-layered dielectric coated PEC cylinder is presented. The method, based on a Green's function described in , is designed to optimally handle layered cylinders where the number of layers is extremely large as might be encountered in structures designed using transformational optics. The method is also tractable for any stratification profile without the need for individual layer analysis. We implement a recently developed numerical method to calculate Bessel functions of complex order and argument. Our method is verified by comparison with previously published results. We also present new …

Reliability-Based Fatigue Assessment Of Mast-Arm Sign Support Structures, Joseph A. Diekfuss

Dissertations (1934 -)

Over the past few decades, there have been issues of poor fatigue performance (the main failure mechanism) of the welded, tube-to-transverse plate connections within sign support structures. Review of the literature has indicated that a considerable amount of research has been devoted to identifying the structural response characteristics of these signs. Others have tried to identify how these connections may be repaired, retrofitted or simply better designed to sustain longer fatigue lives. However, little attention has been given to using a systematic reliability-based approach to assess the risk of fatigue-induced fracture in these structures.

Using a reliability-based approach to solve …

Development Of An Aquaponics Research Program, Richard W. Marklin Jr., Margaret Mathison, Brooke K. Mayer, Mark L. Nagurka, Vikram Cariapa, Michael Schläppi

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Aquaponics: A Sustainable Food Production System That Provides Research Projects For Undergraduate Engineering Students, Richard W. Marklin Jr., Margaret Mathison, Brooke K. Mayer, Mark L. Nagurka, Vikram Cariapa, Jay Schabelski

Mechanical Engineering Faculty Research and Publications

Aquaponics is a closed-loop, recirculating water system in which plants and fish grow together mutualistically. Aquaponics resembles a natural river or lake basin in which fish waste serves as nutrients for the plants, which in turn clean the water for the fish. Tilapia and salad greens or herbs are common fish and plants grown in an aquaponics system. The external inputs to an aquaponics system are fish food, minimal amount of water, and energy for lighting and heating the water for the fish and plants.

Aquaponics is a sustainable, efficient system to raise fish protein and vegetables for human consumption. …

Improving Student Learning Through Use Of An In-Class Material Processing Design Project, Joseph P. Domblesky, James A. Rice, Jay R. Goldberg, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

At Marquette University, hybrid project-based learning has been implemented in an undergraduate mechanical engineering course on materials processing and forming using a team-based approach. The goals of the project are to 1) introduce more active and student-centered activities to improve student engagement and mastery of core concepts, 2) increase students' confidence in their ability to apply what they learned in the course to solving real-world problems, 3) enable students to gain experience using engineering software as part of the learning process and in applications context. While use of process modeling software in materials processing and manufacturing courses is not entirely …

Freehand Sketching For Engineers: A Pilot Study, Richard W. Marklin Jr., Jay R. Goldberg, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper describes a pilot study to evaluate Freehand Sketching for Engineers, a one credit, five week course taught to undergraduate engineering students. The short-term goal of this course was to improve engineering students’ freehand sketching ability and to assess their progress with metrics. The long-term objective (desired learning outcome) of this course is to improve the creativity and innovation of student design projects by enhancing students’ ability to visualize their ideas with freehand sketches. The class met two days a week for 75 min per day. Students were taught to draw simple objects such as electrical boxes, with orthographic, …

Comparative Evaluation Of Operating Life For Phosphate-Specific Ion Exchange Resins, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Probabilistic Sea-Level Rise Hazard Analysis, Ting Lin

Civil and Environmental Engineering Faculty Research and Publications

This paper proposes a framework termed Probabilistic Sea-Level Rise Hazard Analysis (PSLRHA), to integrate the sea-level rise knowledge of current climate change scientific communities for informed engineering and policy decisions that affect coastal infrastructure, populations, and ecosystems. PSLRHA combines probabilities of all emission scenarios with predictions of the resulting sea-level rise over time, in order to compute sea-level rise hazard. PSLRHA also incorporates uncertainties in those sea-level rise predictions, by considering multiple Sea-Level Rise Prediction Models (SLRPMs). The output of the PSLRHA framework could be a Global Sea-Level Rise Hazard Map (GSLRHM) that can be used for Performance- Based Sea-Level …

Analysis Of Laminated Anisotropic Plates And Shells Via A Modified Complementary Energy Principle Approach, Martin Claude Domfang

Dissertations (1934 -)

The present work is concerned with the finite element structural analysis of laminated anisotropic plates and shells. New elements based on a modified complementary energy principle are proposed to improve the analysis of such composite structures. Third order deformation plate and shell models incorporating a convergence parameter are developed to govern the general displacement field.

An eight-node isoparametric quadrilateral element with two independent cross-sectional rotations and three normal displacements is utilized to describe the displacement field. The present modified complementary energy formulation incorporates a number of in-plane strain functions of various orders. The corresponding in-plane stresses for each lamina are …

Reducing Radiation Dose To The Female Breast During Conventional And Dedicated Breast Computed Tomography, Franco Rupcich

Dissertations (1934 -)

The purpose of this study was to quantify the effectiveness of techniques intended to reduce dose to the breast during CT coronary angiography (CTCA) scans with respect to task-based image quality, and to evaluate the effectiveness of optimal energy weighting in improving contrast-to-noise ratio (CNR), and thus the potential for reducing breast dose, during energy-resolved dedicated breast CT.

A database quantifying organ dose for several radiosensitive organs irradiated during CTCA, including the breast, was generated using Monte Carlo simulations. This database facilitates estimation of organ-specific dose deposited during CTCA protocols using arbitrary x-ray spectra or tube-current modulation schemes without the …

Vascular Changes In Type 2 Diabetes Mellitus: Application To Restenosis After Stenting, Hongfeng Wang

Dissertations (1934 -)

Stents used to decrease cardiovascular risk in patients with type 2 diabetes mellitus (T2DM) are prone to increased rates of restenosis. The mechanisms are incompletely elucidated, but low wall shear stress (WSS) and altered intracellular signaling likely contribute. We tested the hypothesis that neointimal hyperplasia (NH) after bare-metal stenting is due to vascular remodeling (enhanced formation of advanced glycation end-products (AGEs), increased downstream vascular resistance (DVR), and decreased WSS), and that decreasing AGEs with ALT-711 (Alagebrium) mitigates this response.

Stents were implanted into the abdominal aorta of Zucker lean (ZL), obese (ZO), and diabetic (ZD) rats. After 21 days, the …

Predictive Pattern Discovery In Dynamic Data Systems, Wenjing Zhang

Dissertations (1934 -)

This dissertation presents novel methods for analyzing nonlinear time series in dynamic systems. The purpose of the newly developed methods is to address the event prediction problem through modeling of predictive patterns. Firstly, a novel categorization mechanism is introduced to characterize different underlying states in the system. A new hybrid method was developed utilizing both generative and discriminative models to address the event prediction problem through optimization in multivariate systems.

Secondly, in addition to modeling temporal dynamics, a Bayesian approach is employed to model the first-order Markov behavior in the multivariate data sequences. Experimental evaluations demonstrated superior performance over conventional …