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 …

Collapsible Silicone Tubes: An In Vitro Model For Tracheal Traction, Kevin D. Garman

Master's Theses (2009 -)

Obstructive sleep apnea (OSA) is characterized by recurrent episodes of airway collapse and airflow limitation during sleep. Fragmented sleep and reductions in blood oxygen saturation lead to several comorbidities, including hypertension, cardiovascular disease, and cerebrovascular disease. Longitudinal forces (tracheal traction) acting on the soft tissues surrounding the upper airway have been proposed to play a significant role in stabilizing the airway and preventing collapse. However, the relative contribution of longitudinal forces as compared to other factors that affect airway stability (airway geometry, tissue properties, muscle activity) remains unclear. This in-vitro study aimed to investigate to what extent longitudinal forces can …

Performance Analysis Of Constant Speed Local Abstacle Avoidance Controller Using A Mpc Algorithym On Granular Terrain, Nicholas Haraus

Master's Theses (2009 -)

A Model Predictive Control (MPC) LIDAR-based constant speed local obstacle avoidance algorithm has been implemented on rigid terrain and granular terrain in Chrono to examine the robustness of this control method. Provided LIDAR data as well as a target location, a vehicle can route itself around obstacles as it encounters them and arrive at an end goal via an optimal route. This research is one important step towards eventual implementation of autonomous vehicles capable of navigating on all terrains. Using Chrono, a multibody physics API, this controller has been tested on a complex multibody physics HMMWV model representing the plant …

The Effects Of A Reduced Force Aerial Bucket Control On Upper Extremity Muscular Demands As Assessed With Surface Electromyography, Casey D. Garces

Master's Theses (2009 -)

A common control for operating aerial bucket trucks for utility companies in North America is called a pistol grip control. Based upon many anecdotal reports of forearm muscle fatigue from workers using this control, Prof. Richard Marklin began an EPRI-sponsored study in 2016 using EMG to determine muscle fatigue of workers while they used the pistol grip. Muscle activity recorded by EMG is a measure of the magnitude of muscle force under controlled conditions. This study confirmed the reports of muscle fatigue in extensor digitorum communis (EDC) muscle in the right forearm. The next phase of the study was to …

Effects Of Random Oscillations On Balance Control In Healthy Young Adults, Jacob Van Dehy

Master's Theses (2009 -)

In human walking, balance control is managed through proactive changes in spatio-temporal parameters of stepping [1]. It has been suggested that continuous disruptions to healthy young adult balance cause greater changes to overall variability of these parameters than a shift in the mean stepping parameters [2]. This suggests that walking may be occurring in a more reactive manner, modulating to maintain balance without increasing the mean significantly. Work using continuous oscillations to treadmill walking suggest there is an interplay between the predictability of a signal used to disrupt subject balance and the degree to which compensation occurs [3]. To determine …

Elucidating The Mechanical, Structural, Functional, And Molecular Mechanisms Involved In Irreversible Vascular Changes In Aortic Coarctation, Brandon Wegter

Master's Theses (2009 -)

Coarctation of the aorta (CoA) is a constriction of the thoracic aorta and is one of the most common congenital cardiovascular defects. Treatment by surgical correction has saved the lives of thousands of children, but many still have a reduced lifespan due to hypertension. Previous results using our novel rabbit model showed that the current treatment guideline of a 20 mmHg blood pressure gradient (BPG) induces irreversible vascular changes, which persisted despite correction. Preliminary data of the downregulation of natriuretic peptide receptor C (NPR-C) in proximal aortic tissue of human patients with CoA serves as the possible underlying mechanism for …

Construction And Characterization Of A Single Stage Dual Diaphragm Gas Gun, Nathaniel Steven Helminiak

Master's Theses (2009 -)

In the interest of studying the propagation of shock waves, this work sets out to design, construct, and characterize a pneumatic accelerator that performs high-velocity flyer plate impact tests. A single stage gas gun with a dual diaphragm breach allows for a non-volatile, reliable experimental testing platform for shock phenomena. This remotely operated gas gun utilizes compressed nitrogen to launch projectiles down a 14 foot long, 2 inch diameter bore barrel, which subsequently impacts a target material of interest. A dual diaphragm firing mechanism allows the 4.5 liter breech to reach a total pressure differential of 10ksi before accelerating projectiles …

Design Of A Passive Ankle Prosthesis With Energy Return That Increases With Increasing Walking Velocity, Alexander J. Folz

Master's Theses (2009 -)

Patients who undergo a transtibial (below the knee) amputation are often met with a difficult decision: selection of a prosthesis. Limitations of currently available prostheses motivate work on a new solution, the EaSY Walk, a passive device that mimics two key aspects of the natural ankle: non-linear rotational stiffness through implementation of a stiffening flexure mechanism and rotational work output that varies as a function of walking velocity to propel the user forward. To achieve the latter, a strategy to convert the maximum available translational energy acquired from deflection along the leg into rotational energy about the ankle joint through …

Hip Joint Function In People With Femoroacetabular Impingement Syndrome, Philip Malloy

Dissertations (1934 -)

Femoroacetabular impingement syndrome (FAIS) is a clinical hip disorder that represents symptomatic contact between the proximal femur and rim of the acetabulum during normal hip range of motion. FAIS has been described as a precursor to hip joint osteoarthritis (OA), and results in physical impairments and functional limitations in young individuals and active adults. Despite tremendous growth in arthroscopic hip surgery for FAIS, little is known about how this disorder affects dynamic hip joint function. The purpose of this dissertation was to investigate hip joint function, during clinical and functional activities, both before and after arthroscopic hip surgery for FAIS. …

Motion Artifact Evaluation Of Coronary Ct Angiography Images, Hongfeng Ma

Dissertations (1934 -)

The objective of this dissertation was to develop and validate an automated algorithm to quantify motion artifact level on coronary CT angiography (CCTA) images. Unlike existing motion artifact reduction techniques that evaluate the relative level of motion artifacts within one exam, this dissertation aims to quantify the absolute level of motion artifacts across exams from varying patients. The ability to quantify absolute motion artifact level enables several potential applications, for example, assessing and comparing two motion artifact reduction techniques. This dissertation includes three specific aims. Aim 1 investigated the absolute motion artifact quantification effectiveness of six motion artifact metrics using …

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 …