Engineering Commons^™

Biomechanical Tolerance Of Whole Lumbar Spines In Straightened Posture Subjected To Axial Acceleration, Brian D. Stemper, Sajal Chirvi, Ninh Doan, Jamie L. Baisden, Dennis J. Maiman, William H. Curry, Narayan Yoganandan, Frank A. Pintar, Glenn Paskoff, Barry S. Shender

Biomedical Engineering Faculty Research and Publications

Quantification of biomechanical tolerance is necessary for injury prediction and protection of vehicular occupants. This study experimentally quantified lumbar spine axial tolerance during accelerative environments simulating a variety of military and civilian scenarios. Intact human lumbar spines (T12‐L5) were dynamically loaded using a custom‐built drop tower. Twenty‐three specimens were tested at sub‐failure and failure levels consisting of peak axial forces between 2.6 and 7.9 kN and corresponding peak accelerations between 7 and 57 g. Military aircraft ejection and helicopter crashes fall within these high axial acceleration ranges. Testing was stopped following injury detection. Both peak force and acceleration were significant …

Optimizing Filter-Probe Diffusion Weighting In The Rat Spinal Cord For Human Translation, Matthew D. Budde, Nathan P. Skinner, L. Tugan Muftuler, Brian D. Schmit, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Load Balancing With Energy Storage Systems Based On Co-Simulation Of Multiple Smart Buildings And Distribution Networks, Shaun Duerr, Cristinel Ababei, Dan M. Ionel

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we present a co-simulation framework that combines two main simulation tools, one that provides detailed multiple building energy simulation ability with Energy-Plus being the core engine, and the other one that is a distribution level simulator, Matpower. Such a framework can be used to develop and study district level optimization techniques that exploit the interaction between a smart electric grid and buildings as well as the interaction between buildings themselves to achieve energy and cost savings and better energy management beyond what one can achieve through techniques applied at the building level only. We propose a heuristic …

Higher Education On Buildings: Case Study In The North Dakota Region, Houjun Yang, Malini Srivastava, Yanmei Xie, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

Because of the growing demand for local skilled professionals to improve the health, energy efficiency, and sustainability of residential and commercial buildings in North Dakota, this case study reports the current situation of higher education relating to buildings in the state’s vicinity, including Minnesota, Montana, North Dakota, and South Dakota. In this region, 116 programs relating to buildings were found in 41 postsecondary institutions, and both their majors and courses were then studied with frequency lists. The frequency information was analyzed over nine sets of curriculum areas at both graduate and undergraduate levels for the four states. After the current …

The Temporal Expression Of Adipokines During Spinal Fusion, Sohrab Virk, Alicia L. Bertone, Hayam Hamaz Hussein, Jeffrey M. Toth, Mari Kaido, Safdar Khan

Biomedical Engineering Faculty Research and Publications

Background Context

Adipokines are secreted by white adipose tissue and have been associated with fracture healing. Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model.

Purpose

Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model.

Study Design

The study design included a laboratory animal model.

Methods

New Zealand white rabbits were assigned to either sham surgery (n=2), unilateral posterior spinal fusion (n=14), or bilateral posterior spinal fusion (n=14). Rabbits were euthanized 1–6 and 10 weeks out from surgery. Fusion was evaluated by …

Development Of A Multiphase Photon Monte Carlo Method For Spray Combustion And Its Application In High-Pressure Conditions, Somesh Roy, Jian Cai, Michael F. Modest

Mechanical Engineering Faculty Research and Publications

In this work the development of a multiphase photon Monte Carlo (PMC) method with a focus on resolving radiative heat transfer in combustion simulations is presented. The multiphase PMC solver can account for description of participating media in both Lagrangian and Eulerian frameworks. The solver is validated against exact solutions in several one-dimensional configurations. The developed solver is then applied to Diesel spray combustions, where liquid spray droplets are assumed to be cold, nonemitting, large, and isotropically scattering. Several formulations for radiative properties of the Diesel spray are first explored. The PMC solver has then been coupled with the multiphase …

A Comparison Of Sensitivity Metrics For Two-Stage Ignition Behavior In Rapid Compression Machines, David Wilson, Casey Allen

Mechanical Engineering Faculty Research and Publications

A rapid compression machine (RCM) multi-zone model is used to simulate the ignition of primary reference fuel (PRF) mixtures that exhibit two-stage ignition behavior. Sensitivity coefficients for each reaction in the PRF mechanism are calculated from four different metrics: (1) first-stage energy release, (2) first-stage pressure rise, (3) first-stage ignition delay time, and (4) total ignition delay time. The sensitivity coefficients are used to provide four unique rankings, and the rankings are compared using Spearman’s rank correlation coefficient. Special emphasis is given to comparing the rankings based on first-stage energy release and total ignition delay time. The level of agreement …

When Will Mems Switches Be Ready For Commercial Products?, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

No abstract provided.

Macroscopic Anisotropic Bone Material Properties In Children With Severe Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Sergey Tarima, Peter Smith, Gerald Harris

Biomedical Engineering Faculty Research and Publications

Children with severe osteogenesis imperfecta(OI) typically experience numerous fractures and progressive skeletal deformities over their lifetime. Recent studies proposed finite element models to assess fracture risk and guide clinicians in determining appropriate intervention in children with OI, but lack of appropriate material property inputs remains a challenge. This study aimed to characterize macroscopic anisotropic cortical bone material properties and investigate relationships with bone density measures in children with severe OI. Specimens were obtained from tibial or femoral shafts of nine children with severe OI and five controls. The specimens were cut into beams, characterized in bending, and imaged by synchrotron …

Clutter Suppression Via Hankel Rank Reduction For Dfrft-Based Vibrometry Applied To Sar, Francisco Pérez, Balu Santhanam, Ranlf Dunkel, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

Hankel rank reduction (HRR) is a method that, by prearranging the data in a Hankel matrix and performing rank reduction via singular value decomposition, suppresses the noise of a time-history vector comprised of the superposition of a finite number of sinusoids. In this letter, the HRR method is studied for performing clutter suppression in synthetic aperture radar (SAR)-based vibrometry. Specifically, three different applications of the HRR method are presented. First, resembling the SAR slow-time signal model, the HRR method is utilized for separating a chirp signal immersed in a sinusoidal clutter. Second, using simulated airborne SAR data with 10 dB …

Robotic Resistance Treadmill Training Improves Locomotor Function In Children With Cerebral Palsy: A Randomized Controlled Pilot Study, Ming Wu, Janis Kim, Deborah J. Gaebler-Spira, Brian D. Schmit, Pooja Arora

Biomedical Engineering Faculty Research and Publications

Objective

To determine whether applying controlled resistance forces to the legs during the swing phase of gait may improve the efficacy of treadmill training as compared with applying controlled assistance forces in children with cerebral palsy (CP).

Design

Randomized controlled study.

Setting

Research unit of a rehabilitation hospital.

Participants

Children with spastic CP (N=23; mean age, 10.6y; range, 6–14y; Gross Motor Function Classification System levels, I–IV).

Interventions

Participants were randomly assigned to receive controlled assistance (n=11) or resistance (n=12) loads applied to the legs at the ankle. Participants underwent robotic treadmill training 3 times a week for 6 weeks (18 …

Sagittal Subtalar And Talocrural Joint Assessment During Ambulation With Controlled Ankle Movement (Cam) Boots, Ben Mchenry, Emily L. Exten, Janelle A. Cross, Karen M. Kruger, Brian Law, Jessica M. Fritz, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background: The purpose of the current study was to determine sagittal plane talocrural and subtalar kinematic differences between barefoot and controlled ankle movement (CAM) boot walking. This study used fluoroscopic images to determine talar motion relative to tibia and calcaneal motion relative to talus.

Methods: Fourteen male subjects (mean age 24.1 ± 3.5 years) screened for normal gait were tested. A fluoroscopy unit was used to collect images at 200 Hz during stance. Sagittal motion of the talocrural and subtalar joints were analyzed barefoot and within short and tall CAM boots.

Results: Barefoot talocrural mean maximum plantar and dorsiflexion were …

Working On A Start-Up: A Case For An Applied Entrepreneurship Oriented Course For Senior Undergraduates, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we describe a new teaching approach whose objective is to implement entrepreneurship-based learning. The proposed teaching approach is essentially a project-based approach, but, with two novel key components that give it the entrepreneurship emphasis. First, the main idea is to divide students into groups of four or five members and have each team go through the process of starting-up a company. This process tries to emulate all steps through which entrepreneurs go when a new start-up idea is taken from concept to product realization. These steps include proposing a novel start-up idea, writing a business plan, coming …

An Advanced Three-Level Active Neutral-Point-Clamped Converter With Improved Fault-Tolerant Capabilities, Ramin Katebi, Jiangbiao He, Nathan Weise

Electrical and Computer Engineering Faculty Research and Publications

A resilient fault-tolerant silicon carbide (SiC) three-level power converter topology is introduced based on the traditional active neutral-point-clamped converter. This novel converter topology incorporates a redundant leg to provide fault tolerance during switch open-circuit faults and short-circuit faults. Additionally, the topology is capable of maintaining full output voltage and maximum modulation index in the presence of switch open and short-circuit faults. Moreover, the redundant leg can be employed to share load current with other phase legs to balance thermal stress among semiconductor switches during normal operation. A 25-kW prototype of the novel topology was designed and constructed utilizing 1.2-kV SiC …

Dynamic Energy Management For Chip Multi-Processors Under Performance Constraints, Milad Ghorbani Moghaddam, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

We introduce a novel algorithm for dynamic energy management (DEM) under performance constraints in chip multi-processors (CMPs). Using the novel concept of delayed instructions count, performance loss estimations are calculated at the end of each control period for each core. In addition, a Kalman filtering based approach is employed to predict workload in the next control period for which voltage-frequency pairs must be selected. This selection is done with a novel dynamic voltage and frequency scaling (DVFS) algorithm whose objective is to reduce energy consumption but without degrading performance beyond the user set threshold. Using our customized Sniper based CMP …

Optimization Of Patch Antennas Via Multithreaded Simulated Annealing Based Design Exploration, James Richie, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we present a new software framework for the optimization of the design of microstrip patch antennas. The proposed simulation and optimization framework implements a simulated annealing algorithm to perform design space exploration in order to identify the optimal patch antenna design. During each iteration of the optimization loop, we employ the popular MEEP simulation tool to evaluate explored design solutions. To speed up the design space exploration, the software framework is developed to run multiple MEEP simulations concurrently. This is achieved using multithreading to implement a manager-workers execution strategy. The number of worker threads is the same …

Modeling Dormant Fruit Trees For Agricultural Automation, Henry Medeiros, Donghun Kim, Jianxin Sun, Hariharan Seshadri, Shayan A. Akbar, Noha M. Elfiky, Johnny Park

Electrical and Computer Engineering Faculty Research and Publications

Dormant pruning of fruit trees is one of the most costly and labor‐intensive activities in specialty crop production. We present a system that solves the first step in the process of automated pruning: accurately measuring and modeling the fruit trees. Our system employs a laser sensor to collect observations of fruit trees from multiple perspectives, and it uses these observations to measure parameters needed for pruning. A split‐and‐merge clustering algorithm divides the collected data into three sets of points: trunk candidates, junction point candidates, and branches. The trunk candidates and junction point candidates are then further refined by a robust …

Protection By Inhaled Hydrogen Therapy In A Rat Model Of Acute Lung Injury Can Be Tracked In Vivo Using Molecular Imaging, Said H. Audi, Elizabeth R. Jacobs, Xiao Zhang, Amadou K.S. Camara, Ming Zhao, Meetha M. Medhora, Benjamin Michael Rizzo, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

Inhaled hydrogen gas (H₂) provides protection in rat models of human acute lung injury (ALI). We previously reported that biomarker imaging can detect oxidative stress and endothelial cell death in vivo in a rat model of ALI. Our objective was to evaluate the ability of ^99mTc-hexamethylpropyleneamineoxime (HMPAO) and ^99mTc-duramycin to track the effectiveness of H₂ therapy in vivo in the hyperoxia rat model of ALI. Rats were exposed to room air (normoxia), 98% O₂ + 2% N₂ (hyperoxia) or 98% O₂ + 2% H₂ (hyperoxia+H₂) for up to 60 …

Treating A 20 Mm Hg Gradient Alleviates Myocardial Hypertrophy In Experimental Aortic Coarctation, David C. Wendell, Ingeborg Friehs, Margaret M. Samyn, Leanne Harmann, John F. Ladisa

Biomedical Engineering Faculty Research and Publications

Background

Children with coarctation of the aorta (CoA) can have a hyperdynamic and remodeled left ventricle (LV) from increased afterload. Literature from an experimental model suggests the putative 20 mm Hg blood pressure gradient (BPG) treatment guideline frequently implemented in CoA studies may permit irreversible vascular changes. LV remodeling from pressure overload has been studied, but data are limited following correction and using a clinically representative BPG.

Materials and methods

Rabbits underwent CoA at 10 weeks to induce a 20 mm Hg BPG using permanent or dissolvable suture thereby replicating untreated and corrected CoA, respectively. Cardiac function was evaluated at …

Climate, Not Conflict, Explains Extreme Middle East Dust Storm, Anthony J. Parolari, Dan Li, Elie Bou-Zeid, Gabriel Katul, Shmuel Assouline

Civil and Environmental Engineering Faculty Research and Publications

The recent dust storm in the Middle East (September 2015) was publicized in the media as a sign of an impending ‘Dust Bowl.’ Its severity, demonstrated by extreme aerosol optical depth in the atmosphere in the 99th percentile compared to historical data, was attributed to the ongoing regional conflict. However, surface meteorological and remote sensing data, as well as regional climate model simulations, support an alternative hypothesis: the historically unprecedented aridity played a more prominent role, as evidenced by unusual climatic and meteorological conditions prior to and during the storm. Remotely sensed normalized difference vegetation index demonstrates that vegetation cover …

Hydrologic Transport Of Dissolved Inorganic Carbon And Its Control On Chemical Weathering, Salvatore Calabrese, Anthony J. Parolari, Amilcare Porporato

Civil and Environmental Engineering Faculty Research and Publications

Chemical weathering is one of the major processes interacting with climate and tectonics to form clays, supply nutrients to soil microorganisms and plants, and sequester atmospheric CO₂. Hydrology and dissolution kinetics have been emphasized as factors controlling chemical weathering rates. However, the interaction between hydrology and transport of dissolved inorganic carbon (DIC) in controlling weathering has received less attention. In this paper, we present an analytical model that couples subsurface water and chemical molar balance equations to analyze the roles of hydrology and DIC transport on chemical weathering. The balance equations form a dynamical system that fully determines …

A Comparative Life Cycle Assessment Between A Metered Dose Inhaler And Electric Nebulizer, Brandon Goulet, Lars E. Olson, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Life cycle assessment (LCA) evaluates the environmental impact of a product based on the materials and processes used to manufacture the item as well as the item’s use and disposal. The objective of this LCA was to evaluate and compare the environmental impact of a metered dose inhaler, specifically the Proventil® HFA inhaler (Merk & Co., Inc., Kenilworth, NJ, USA), and an electric nebulizer, specifically the DeVilbiss Pulmo-Aide® nebulizer (DeVilbiss, Port Washington, NY, USA). GaBi LCA software was used to model the global warming potential (GWP) of each product by using substantiated data and well-justified assumptions for the components, manufacturing, …

Boom And Bust Carbon-Nitrogen Dynamics During Reforestation, Anthony J. Parolari, Megan L. Mobley, Allan R. Bacon, Gabriel Katul, Daniel Deb. Richter, Amilcare Porporato

Civil and Environmental Engineering Faculty Research and Publications

Legacies of historical land use strongly shape contemporary ecosystem dynamics. In old-field secondary forests, tree growth embodies a legacy of soil changes affected by previous cultivation. Three patterns of biomass accumulation during reforestation have been hypothesized previously, including monotonic to steady state, non-monotonic with a single peak then decay to steady state, and multiple oscillations around the steady state. In this paper, the conditions leading to the emergence of these patterns is analyzed. Using observations and models, we demonstrate that divergent reforestation patterns can be explained by contrasting time-scales in ecosystem carbon-nitrogen cycles that are influenced by land use legacies. …

Increasing Atmospheric Humidity And Co2 Concentration Alleviate Forest Mortality Risk, Yanlan Liu, Anthony J. Parolari, Mukesh Kumar, Chang-Wei Huang, Gabriel Katul, Amilcare Porporato

Civil and Environmental Engineering Faculty Research and Publications

Climate-induced forest mortality is being increasingly observed throughout the globe. Alarmingly, it is expected to exacerbate under climate change due to shifting precipitation patterns and rising air temperature. However, the impact of concomitant changes in atmospheric humidity and CO₂ concentration through their influence on stomatal kinetics remains a subject of debate and inquiry. By using a dynamic soil–plant–atmosphere model, mortality risks associated with hydraulic failure and stomatal closure for 13 temperate and tropical forest biomes across the globe are analyzed. The mortality risk is evaluated in response to both individual and combined changes in precipitation amounts and their seasonal …

A Novel Real-Time Non-Invasive Hemoglobin Level Detection Using Video Images From Smartphone Camera, Golam Mushih Tanimul Ahsan, Md. O. Gani, Md Kamrul Hasan, Sheikh Iqbal Ahamed, William Chu, Mohammad Adibuzzaman, Joshua Field

Electrical and Computer Engineering Faculty Research and Publications

Hemoglobin level detection is necessary for evaluating health condition in the human. In the laboratory setting, it is detected by shining light through a small volume of blood and using a colorimetric electronic particle counting algorithm. This invasive process requires time, blood specimens, laboratory equipment, and facilities. There are also many studies on non-invasive hemoglobin level detection. Existing solutions are expensive and require buying additional devices. In this paper, we present a smartphone-based non-invasive hemoglobin detection method. It uses the video images collected from the fingertip of a person. We hypothesized that there is a significant relation between the fingertip …

Micro-Contacts Testing Using A Micro-Force Sensor Compatible With Biological Systems, Ronald A. Coutu Jr., Dushyant Tomer

Electrical and Computer Engineering Faculty Research and Publications

This paper presents the performance and reliability testing of microelectromechanical systems (MEMS) switches by using a micro-force sensor which was originally designed/used to conduct mechanical testing of biological cells. MEMS switches are key components for radio frequency (RF) applications due to their extremely low power consumption and small geometries over conventional technologies. However, unstable electrical contact resistance severely degrades the performance and reliability of such micro-switches. Therefore, our focus is to improve the performance and reliability of “cold” switched micro-contacts by using novel contact materials and engineered micro-contact surfaces. The contact metallurgies considered in this work are “similar” thin film …

A Bayesian Estimation Model For Transient Engine Exhaust Characterization Using Fourier Transform Infrared Spectroscopy, David Wilson, Casey Allen

Mechanical Engineering Faculty Research and Publications

Comprehensive emissions models extensively use engine exhaust data from vehicle experiments to represent the relationship between fuel composition and pollutants. However, the predicted emissions from these models often neglect the effects of transients and speed-load history. Fourier transform infrared (FTIR) spectroscopy is a high frequency measurement technique capable of comprehensive speciation. However, due to long residence times of exhaust within a FTIR spectrometer gas cell, FTIR measurements are contaminated by the effects of historical emissions, precluding the attainment of time-resolved engine exhaust data. This work presents a Bayesian estimation model for processing FTIR measurements to obtain accurate estimations of instantaneous …

Run-Out Based Crossed Roller Bearing Life Prediction By Utilization Of Accelerated Testing Approach And Fe Numerical Models, Luca Quagliato, Dongwook Kim, Nara Lee, Soyoung Hwang, Joseph P. Domblesky, Naksoo Kim

Mechanical Engineering Faculty Research and Publications

Surface wear and spalling phenomena are the most important factors affecting roller bearing performance and operational lifetime, in terms of number of cycles the bearing can operate. Although bearing life has been traditionally defined by the onset of spalling, as specified by international standard ISO 281, this definition does not always reflect the real operational conditions, since bearing wear can also represent a failure criterion when excessive run-out occurs. In such cases, bearing life needs to be predicted according to the amount of bearing run-out resulting from wear due to load and number of cycles. In the current study, the …

A Spectral Ct Method To Directly Estimate Basis Material Maps From Experimental Photon-Counting Data, Tal Gilat Schmidt, Rina Foygel Barber, Emil Y. Sidky

Biomedical Engineering Faculty Research and Publications

The proposed spectral CT method solves the constrained one-step spectral CT reconstruction (cOSSCIR) optimization problem to estimate basis material maps while modeling the nonlinear X-ray detection process and enforcing convex constraints on the basis map images. In order to apply the optimization-based reconstruction approach to experimental data, the presented method empirically estimates the effective energy-window spectra using a calibration procedure. The amplitudes of the estimated spectra were further optimized as part of the reconstruction process to reduce ring artifacts. A validation approach was developed to select constraint parameters. The proposed spectral CT method was evaluated through simulations and experiments with …

Data Improving In Time Series Using Arx And Ann Models, Hermine Nathalie Akouemo Kengmo Kenfack, Richard J. Povinelli

Electrical and Computer Engineering Faculty Research and Publications

Anomalous data can negatively impact energy forecasting by causing model parameters to be incorrectly estimated. This paper presents two approaches for the detection and imputation of anomalies in time series data. Autoregressive with exogenous inputs (ARX) and artificial neural network (ANN) models are used to extract the characteristics of time series. Anomalies are detected by performing hypothesis testing on the extrema of the residuals, and the anomalous data points are imputed using the ARX and ANN models. Because the anomalies affect the model coefficients, the data cleaning process is performed iteratively. The models are re-learned on “cleaner” data after an …