Digital Commons Network^™

Aortic Remodeling Kinetics In Response To Coarctation-Induced Mechanical Perturbations, Arash Ghorbannia, Mehdi Maadooliat, Ronald K. Woods, Said H. Audi, Brandon J. Tefft, Claudio Chiastra, El Sayed H. Ibrahim, John F. Ladisa Jr.

Biomedical Engineering Faculty Research and Publications

Background: Coarctation of the aorta (CoA; constriction of the proximal descending thoracic aorta) is among the most common congenital cardiovascular defects. Coarctation-induced mechanical perturbations trigger a cycle of mechano-transduction events leading to irreversible precursors of hypertension including arterial thickening, stiffening, and vasoactive dysfunction in proximal conduit arteries. This study sought to identify kinetics of the stress-mediated compensatory response leading to these alterations using a preclinical rabbit model of CoA.

Methods: A prior growth and remodeling (G&R) framework was reformulated and fit to empirical measurements from CoA rabbits classified into one control and nine CoA groups of various severities …

Utility And Usability Of Two Forms Of Supplemental Vibrotactile Kinesthetic Feedback For Enhancing Movement Accuracy And Efficiency In Goal-Directed Reaching, Ramsey K. Rayes, Rachel N. Mazorow, Leigh A. Mrotek, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Recent advances in wearable sensors and computing have made possible the development of novel sensory augmentation technologies that promise to enhance human motor performance and quality of life in a wide range of applications. We compared the objective utility and subjective user experience for two biologically inspired ways to encode movement-related information into supplemental feedback for the real-time control of goal-directed reaching in healthy, neurologically intact adults. One encoding scheme mimicked visual feedback encoding by converting real-time hand position in a Cartesian frame of reference into supplemental kinesthetic feedback provided by a vibrotactile display attached to the non-moving arm and …

Non-Traditional Learning In Stem: How Students Autonomy And The Impact Of Teacher Delivery Develops Deeper Conceptual Understanding At The Middle School Level, Sarah Kelly

Dissertations and Theses @ UNI

Non-traditional forms of curriculum development and delivery have shown particular promise in supporting the autonomy of students particularly in relation to science. Programs such as OPENSCIED are inquiry based- learning that promotes problem solving skills and cross curricular development supported by the Next Generation Science Standards (NGSS). This mixed method research study sought to illuminate how these types of curricular programs influence student autonomy and learning, especially with the implementation of OpenSciEd within Des Moines Public Schools. The study utilizes student state testing (ISASP)data alongside teacher surveys, interviews and observations to investigate the strengths or potential deficits of inquiry based …

The Critical Role Of Happiness In Education: Resilience, Retention, And What Happy Teachers Do Differently, Jill Marie Hayes White

Dissertations and Theses @ UNI

Teachers are unhappy, stressed, and leaving the field at an alarming rate. This paper analyzes how teacher happiness is related to resilience and retention. It also looks for patterns that identify what happy teachers do differently at work. To complete this investigation, current K-12 public school teachers throughout Iowa completed electronic surveys that assessed their happiness, resilience, and work life. These surveys included the Subjective Happiness Scale (Lyubomirsky & Lepper, 1999), the Brief Resilience Scale (Smith, et al., 2008), and 14 additional survey questions created by the researcher. Correlational, comparative, and descriptive analyses were completed to examine potential relationships and …

Additive P-Value Combination Test, Xing Ling

Dissertations, Master's Theses and Master's Reports

This dissertation includes four Chapters. A brief description of each chapter is organized as follows.

In Chapter 1, some developments on multiple hypotheses tests are introduced. Some preliminaries about the definition and the assumption are included.

In Chapter 2, a Stable Combination Test is proposed to combine $p$-values from multiple hypotheses tests. We show the proposed method controls the family-wise error rate at the target level and maintains asymptotically optimal power even when the elementary p-values from the individual hypotheses are dependent.

In Chapter 3, a deeper dig into the additive p-value combination test is performed. A common idea behind …

Quantifying The Impact Of Wide Base Tires On Pavement Performance In Michigan, Lei Yin

Dissertations, Master's Theses and Master's Reports

This study aimed to investigate the use of wide base tires (WBT) in Michigan to quantify the effect of different percentages of WBT loads on flexible and rigid pavements. Surveys and field investigations were conducted to quantify the WBT usage in Michigan. The JULEA (for flexible pavements) and Illislab (for JPCP) software programs were used to calculate the mechanical response between dual tire (DT) and WBT loads, while the Mechanical-Empirical (ME) pavement design process was utilized for damage accumulation and pavement distress analysis. Investigation results rationalized the assumption of WBT proportion for design purposes as 10% currently and up to …

Climate Changes In El Salvador: Impacts Of ‘La Canícula’ (Midsummer Drought) On Agricultural Practices And Decision-Making In Rural Communities, Paola M. Rivera González

Dissertations, Master's Theses and Master's Reports

The Central American Dry Corridor (CADC), a tropical, dry-forest region, is characterized by distinct rainy and dry seasons, which influence the local agricultural calendar and planting decisions in rural communities. La canícula is a period of decreased precipitation during the rainy season, which occurs during the corn-planting season in El Salvador. La canícula is expected to change in intensity and duration in the next decades, which would impact small-scale farmers and their livelihoods. Climate variability and uncertainty has led to crop loss, water scarcity, and food insecurity in rural communities dependent on subsistence farming. Farmers’ experiences with a changing climate …

Evaluation Of Lidar Uncertainty And Applications Towards Slam In Off-Road Environments, Zachary D. Jeffries

Dissertations, Master's Theses and Master's Reports

Safe and robust operation of autonomous ground vehicles in all types of conditions and environment necessitates complex perception systems and unique, innovative solutions. This work addresses automotive lidar and maximizing the performance of a simultaneous localization and mapping stack. An exploratory experiment and an open benchmarking experiment are both presented. Additionally, a popular SLAM application is extended to use the type of information gained from lidar characterization, demonstrating the performance gains and necessity to tightly couple perception software and sensor hardware. The first exploratory experiment collects data from child-sized, low-reflectance targets over a range from 15 m to 35 m. …

Mixing, Metabolism, And Climate Change: A Modeling Case Study Of A Shallow Hypereutrophic, Polymictic Lake, Benjamin C. Reuss

Dissertations, Master's Theses and Master's Reports

Globally, lakes are sites of significant carbon cycling, respiring an estimated 0.07 to 0.15 Pg as CO2 and sequestering 0.03 to 0.07 Pg C in sediments annually. These processes can be affected by nutrient availability, with seasonal mixing regulating nutrient transport in monomictic and dimictic systems. However, the effect of intermittent mixing on ecosystem production in polymictic systems has been much less studied. The timing and frequency of lake mixing are expected to be altered by climate change, which has the potential to impact nutrient transport. The first chapter of this thesis introduces lake mixing dynamics and indices of mixing. …

Establishing Degradation Of The C. Elegans Dream Complex In The Germline, Christina M. Boody

Dissertations, Master's Theses and Master's Reports

The highly conserved Dp, Rb, E2F, and MuvB (DREAM) complex is responsible for the transcriptional repression of cell cycle genes. The DREAM complex has been extensively studied in somatic (non-reproductive) cells, but there is a gap in knowledge regarding how the DREAM complex may function in germ (reproductive) cells. To demonstrate loss-of-function of DREAM in the germline, we used the auxin-inducible degron (AID) system to establish degradation of LIN-54, a subunit of DREAM’s MuvB subcomplex, and the Retinoblastoma-like pocket protein LIN-35 in C. elegans. Using transgenic lines that express the Arabidopsis thaliana TIR1 E3 ubiquitin ligase ubiquitously through all …

Developing A Regional Scale Landslide Early Warning System In A Data-Sparse Region Using Remote Sensing, Geostatistics, And Google Earth Engine, Vishnu Chakrapani Lekha

Dissertations, Master's Theses and Master's Reports

The Landslide Early Warning System (LEWS) is a non-structural approach to mitigate landslide risk by alerting vulnerable communities at an early stage. This study aimed to develop a regional LEWS for rain-induced shallow landslides in Idukki, a mountainous district in India with sparse rainfall data. The landslide model consists of a rainfall component and a slope stability component. Satellite precipitation data can be used in data-sparse regions, but they must be calibrated because they tend to underestimate rainfall. To improve the accuracy of satellite data, this study used a geostatistics-based multi-criteria approach to identify optimal locations to install new rain …

Chemical Decomposition Of Flexible Polyurethane Foam To Generate A Media For Microbial Upcycling, Kaushik Baruah

Dissertations, Master's Theses and Master's Reports

Polyurethane waste is becoming a global concern as a large amount is being disposed of in landfills every year, and only a fraction is being recycled. Several polyurethane recycling techniques exist, of which ammonolysis and base-catalyzed hydrolysis is the least explored. Flexible polyurethane foam (FPUF) decomposition can generate amines that can act as a carbon source for the growth of microbial consortia. This study aims to generate a novel media capable of microbial upcycling via ammonolysis and base-catalyzed hydrolysis of flexible polyurethane foams (FPUFs) using ammonium hydroxide and subsequently determine the reaction conditions for maximum solubilization of polyurethane foam in …

Alternative Method For Low Frequency Impact Sound Measurement For Building Field Tests, Sunit Girdhar

Dissertations, Master's Theses and Master's Reports

What do high heels, dog nails, and dragging furniture have in common? They are all frequent sources of noise pollution and annoyance in multi-story buildings. Building codes exist to control and mitigate such noise, but these codes are outdated and fail to protect the residents against noise annoyance. Footstep noise is still the number one cause of complaints among the residents. The impact performance of floor-ceiling assemblies is characterized using a single-number rating called the Impact Sound Rating (ISR). A standard tapping machine is used in pre-defined locations on the floor and the radiated Sound Pressure Level (SPL) is measured …

Virus Inactivation By Novel Virucidal Materials, Sneha Singh

Dissertations, Master's Theses and Master's Reports

The development of virucidal coatings to inactivate a broad spectrum of viruses has gained popularity. Antiviral coating of personal protective equipment such as facial coverings can reduce the accumulation of viral load and mitigate transmission of airborne illnesses, which occur primarily through direct contact with respiratory aerosols or droplets carrying infectious viruses. Moreover, modification of PPE to inactivate viruses upon contact improves their reusability and reduces waste. Coating high frequency touch surfaces with similar virucidal coatings can reduce the risk of disease transmission associated with contaminated surfaces. This study explores the development of three novel virucidal materials to control the …

Structural Analysis And Slip Kinematics Of The Keweenaw Fault System Between Bête Grise Bay And Gratiot Lake, Keweenaw County, Michigan, Daniel J. Lizzadro-Mcpherson

Dissertations, Master's Theses and Master's Reports

The Keweenaw fault is perhaps the most significant geologic structure on the Keweenaw Peninsula, with an estimated 7-11 km of reverse slip juxtaposing volcanic strata of the ~1.1 Ga Portage Lake Volcanics above ~1.0 Ga Jacobsville Sandstone. The fault has been interpreted as a rift-bounding normal fault later inverted by compressional pulses of the Grenville Orogeny or, more recently, as part of a detached thrust fault system unrelated to an earlier normal fault. The fault is shown on published maps as a single continuous fault trace whose sinuosity implies multiple fault segments and complex slip dynamics. Mapping along Bête Grise …

Neuroevolution And Machine Learning Research Applied To Connected Automated Vehicle And Powertrain Control, Frédéric F. Jacquelin

Dissertations, Master's Theses and Master's Reports

This dissertation focuses on advancing Predictive Energy Management (PrEM) functions applied to modern connected and automated vehicles (CAV) cohorts. PrEM aims to utilize connectivity and ADAS functions to adaptively minimize vehicle energy consumption in a wide array of operations, extending the original control designed around a reduced set of test cycle procedures to adapt to real-world stochastic operating conditions. This research document is built upon three journal publications covering two PrEM schemes; the global cohort and local vehicle optimization paths. Both optimal control solutions are generated using various Neuroevolution centric processes.

Chapter 1 discusses the methods and reasoning behind the …

Study Of Electronic And Magnetic Properties Of Bilayer Graphene Nanoflakes And Bimetallic Chalcogenides Using First-Principles Density Functional Theory And Machine Learning, Dharmendra Pant

Dissertations, Master's Theses and Master's Reports

Graphene, a one-atom-thick material, has been a wonder material since its discovery because of its superlative electronic, mechanical, and optical properties. When a layer of graphene is rotated over another layer, it exhibits many intriguing behaviors, ranging from superconductivity to the anomalous Hall effect to ferromagnetism at a magic angle of 1°, and hence the twisted bilayer graphene has been the subject of intense research in recent years. The surge in interest in this moiré structure can be attributed to the emergence of electronic flat minibands near the magic angle. Here, we studied the electronic and magnetic properties of twisted …

Multiscale Molecular Modeling Studies Of The Dynamics And Catalytic Mechanisms Of Iron(Ii)- And Zinc(Ii)-Dependent Metalloenzymes, Sodiq O. Waheed

Dissertations, Master's Theses and Master's Reports

Enzymes are biological systems that aid in specific biochemical reactions. They lower the reaction barrier, thus speeding up the reaction rate. A detailed knowledge of enzymes will not be achievable without computational modeling as it offers insight into atomistic details and catalytic species, which are crucial to designing enzyme-specific inhibitors and impossible to gain experimentally. This dissertation employs advanced multiscale computational approaches to study the dynamics and reaction mechanisms of non-heme Fe(II) and 2-oxoglutarate (2OG) dependent oxygenases, including AlkB, AlkBH2, TET2, and KDM4E, involved in DNA and histone demethylation. It also focuses on Zn(II) dependent matrix metalloproteinase-1 (MMP-1), which helps …

Automatic Optical Inspection-Based Pcb Fault Detection Using Image Processing, Shruti Rajiv Vaidya

Dissertations, Master's Theses and Master's Reports

Increased Printed Circuit Board (PCB) route complexity and density combined with the growing demand for low-scale rapid prototyping has increased the desire for Automated Optical Inspection (AOI) that reduces prototyping time and production costs by detecting defects early in the production process. Traditional defect detection method of human visual inspection is not only error prone but is also time-consuming given the growing complex and dense circuitry of modern-day electronics. Electric contact-based testing, either in the form of a bed of nails testing fixture or a flying probe system, is costly for low-rate rapid prototyping. An AOI is a non-contact test …

Quantifying The Evolution Of Strengthening Mechanisms For Commercially Produced Niobium And Titanium Hsla Steel Sheet, Isabella M.W. Jaszczak

Dissertations, Master's Theses and Master's Reports

Strength uniformity along the coil length of commercially produced high-strength, low-alloy (HSLA) steel hot-rolled sheet is crucial to avoid the downgrading of product that does not meet strength specifications. In addition to contributing to precipitation strengthening through the growth of niobium-titanium carbides ((Nb,Ti)-C), niobium hinders austenite recrystallization and refines ferrite grain size. The potency of these strengthening mechanisms relies heavily on the austenite to ferrite transformation kinetics of the hot-rolling process. While niobium’s effect on precipitation strengthening, Hall-Petch strengthening, dislocation strengthening, and solute strengthening have all been studied in literature independently, the interactions of these mechanisms with each other and …

Finer Details Of Language Modeling: Text Segmentation, Working Within Resource Limits, And Watermarking, Evan Gordon Lucas

Dissertations, Master's Theses and Master's Reports

Language modeling is a vast sub-field of natural language processing and this work focuses on solving some specific problems within that field. Technically, the work falls into a number of sub-categories within natural language processing; how to segment texts, improving sparse transformer performance for summarization tasks, character level models for dialect determination, watermarking of large language models, and a general method of incorporating minimal human feedback for continual or online learning. Despite touching on many small areas, they all connect as being related to the very general problem of handling sequential data. Language and text can be thought of as …

Neuromorphic Computing Applications In Robotics, Noah Zins

Dissertations, Master's Theses and Master's Reports

Deep learning achieves remarkable success through training using massively labeled datasets. However, the high demands on the datasets impede the feasibility of deep learning in edge computing scenarios and suffer from the data scarcity issue. Rather than relying on labeled data, animals learn by interacting with their surroundings and memorizing the relationships between events and objects. This learning paradigm is referred to as associative learning. The successful implementation of associative learning imitates self-learning schemes analogous to animals which resolve the challenges of deep learning. Current state-of-the-art implementations of associative memory are limited to simulations with small-scale and offline paradigms. Thus, …

Microscopic And Laboratory Scale Characterization Methods To Evaluate Biomass Deconstruction, Meenaa Chandrasekar

Dissertations, Master's Theses and Master's Reports

Renewable fuels from lignocellulosic biomass are an appealing option because they can seamlessly integrate into the existing fuel distribution infrastructure. Lignocellulosic biomass constitutes nonedible plant material obtained from plant cell walls. The natural recalcitrance of lignocellulosic biomass poses a challenge in accessing the cell wall carbohydrates during biochemical conversion. Despite various approaches, enzymatic hydrolysis of lignocellulosic biomass remains economically impractical due to incomplete knowledge about biomass recalcitrance and the influence of environmental factors on biomass quality.

The first goal of this dissertation was to construct a microfluidic imaging reactor to better understand the tissue-specific deconstruction of plant materials. Confocal laser …

Machine Learning Methods For Prediction Of Human Infectious Virus And Imputation Of Hla Alleles, Xiaoqing Gao

Dissertations, Master's Theses and Master's Reports

This dissertation contains three Chapters. The following is a concise description of each Chapters.

In Chapter 1, we introduced the Random Forest, a machine learning method, to foresee whether a virus is capable of infecting humans. The Covid pandemic informs us the importance of predicting the ability of a zoonotic virus that can infect humans from its genomic sequence. We used the -mer with and as features of a virus to predict if it can affect humans. We further employed the Boruta algorithm to select the important features, then fed those important features into the Random Forest method to train …

Remote Sensing Approach For Terramechanics Applications Utilizing Machine And Deep Learning, Jordan J. Ewing

Dissertations, Master's Theses and Master's Reports

Terrain traversability is critical for developing Go/No Go maps, significantly impacting a mission's success. To predict the mobility of a vehicle over a terrain, one must understand the soil characteristics. In situ measurements performed by soldiers in the field are the current method of collecting this information, which is time-consuming, are only point measurements, and can put soldiers in harm's way. Therefore, this study investigates using remote sensing as an alternative approach to characterize terrain properties.

This approach will explore the relationships between electromagnetic radiation and soil types with varying properties. Optical, thermal, and hyperspectral sensors will be used to …

Optimizing The Extrudability Of 6082 Aluminum By Varying The Magnesium And Silicon Concentration, Eli A. Harma

Dissertations, Master's Theses and Master's Reports

Alloy 6082 aluminum is used for high-volume manufacturing in the automotive industry due to its high strength, impact performance, and corrosion resistance. However, given these improved properties, the alloy has decreased formability compared to other 6xxx series alloys, especially in the extrusion process. Controlling the dynamic recovery and recrystallization properties by changing the additions of Mg and Si can improve the hot deformation properties. Five alloys of varying Mg and Si concentrations between 0.6 to 1.2wt% Mg and 0.7 to 1.3wt% Si were made with constant concentrations of Cr, Fe, and Mn and the same homogenization heat treatment. The proposed …

The Flight Attendants Of Academia: Liminality, Emotional Labor, And Feminization In Graduate Student Writing Program Administrators, Laura Vidal Chiesa

Dissertations, Master's Theses and Master's Reports

Writing Program Administration (WPA) is an interdisciplinary field that addresses the management and development of writing programs in educational institutions. WPA entails writing instruction pedagogy, curriculum design, assessment, and faculty development pertaining to the teaching of writing. Graduate students in Humanities and English-based programs typically fill this position which can offer a career trajectory. However, the position is often experienced as demanding, unrewarding and does not deliver on the career-enhancing experience it seems to promise. Historically, this is unsurprising given that the position has been a subordinated role occupied by women in composition. And yet, the troubles besetting contemporary graduate …

Study Of Nanocomposite Materials Using Molecular Dynamics, Prashik Sunil Gaikwad

Dissertations, Master's Theses and Master's Reports

There is an increase in demand for new lightweight structural materials in the aerospace industry for more efficient and affordable human space travel. Polymer matrix composites (PMCs) with reinforcement material as carbon nanotubes (CNTs) have shown exceptional increase in the mechanical properties. Flattened carbon nanotubes (flCNTs) are a primary component of many carbon nanotube (CNT) yarn and sheet materials, which are promising reinforcements for the next generation of ultra-strong composites for aerospace applications. These flCNT/polymer materials are subjected to extreme pressure and temperature during curing process. Therefore there is a need to investigate the evolution of properties during the curing …

Machine Learning And Deep Learning Approaches For Gene Regulatory Network Inference In Plant Species, Sai Teja Mummadi

Dissertations, Master's Theses and Master's Reports

The construction of gene regulatory networks (GRNs) is vital for understanding the regulation of metabolic pathways, biological processes, and complex traits during plant growth and responses to environmental cues and stresses. The increasing availability of public databases has facilitated the development of numerous methods for inferring gene regulatory relationships between transcription factors and their targets. However, there is limited research on supervised learning techniques that utilize available regulatory relationships of plant species in public databases.

This study investigates the potential of machine learning (ML), deep learning (DL), and hybrid approaches for constructing GRNs in plant species, specifically Arabidopsis thaliana, …

Explicit Rule Learning: A Cognitive Tutorial Method To Train Users Of Artificial Intelligence/Machine Learning Systems, Anne Linja

Dissertations, Master's Theses and Master's Reports

Today’s intelligent software systems, such as Artificial Intelligence/Machine Learning systems, are sophisticated, complicated, sometimes complex systems. In order to effectively interact with these systems, novice users need to have a certain level of understanding. An awareness of a system’s underlying principles, rationale, logic, and goals can enhance the synergistic human-machine interaction. It also benefits the user to know when they can trust the systems’ output, and to discern boundary conditions that might change the output. The purpose of this research is to empirically test the viability of a Cognitive Tutorial approach, called Explicit Rule Learning. Several approaches have been used …