Engineering Commons^™

Enhancing Bioethanol Fermentation Through Removal Of Acetic Acid Using Liquid-Liquid Extraction, Mahdieh Aghazadeh

Open Access Dissertations

The concern for the ever growing human population as well as the depletion of fossil fuel resources and their impact on global warming have long been motivations for the researchers to investigate means for sustainable producing carbon-neutral energy. Second-generation biofuel refers to liquid fuels that are produced from non-food resources and reduce the total greenhouse gas emission by at least 60 %. Acetic acid has been shown to be one of the most ubiquitous fermentation inhibitors in a bioethanol production facility which slows down the bioethanol production and reduces its yield through inhibition of the ethanol producing microorganisms. The use …

Improving The Mechanistic Study Of Neuromuscular Diseases Through The Development Of A Fully Wireless And Implantable Recording Device, Rebecca A. Bercich

Open Access Dissertations

Neuromuscular diseases manifest by a handful of known phenotypes affecting the peripheral nerves, skeletal muscle fibers, and neuromuscular junction. Common signs of these diseases include demyelination, myasthenia, atrophy, and aberrant muscle activity—all of which may be tracked over time using one or more electrophysiological markers. Mice, which are the predominant mammalian model for most human diseases, have been used to study congenital neuromuscular diseases for decades. However, our understanding of the mechanisms underlying these pathologies is still incomplete. This is in part due to the lack of instrumentation available to easily collect longitudinal, in vivo electrophysiological activity from mice. There …

On The 3d Point Cloud For Human-Pose Estimation, Kai-Chi Chan

Open Access Dissertations

This thesis aims at investigating methodologies for estimating a human pose from a 3D point cloud that is captured by a static depth sensor. Human-pose estimation (HPE) is important for a range of applications, such as human-robot interaction, healthcare, surveillance, and so forth. Yet, HPE is challenging because of the uncertainty in sensor measurements and the complexity of human poses. In this research, we focus on addressing challenges related to two crucial components in the estimation process, namely, human-pose feature extraction and human-pose modeling.

In feature extraction, the main challenge involves reducing feature ambiguity. We propose a 3D-point-cloud feature called …

A Transfer Network Linking Earth, Moon, And The Triangular Libration Point Regions In The Earth-Moon System, Lucia R. Capdevila

Open Access Dissertations

In the near future, several space applications in the Earth-Moon system may require a spacecraft to hold a stable motion, but the transfer trajectory infrastructure to access such stable motions has not been fully investigated yet. The triangular libration points, L 4and L5, in the Earth-Moon system have long been thought of as ideal locations for a communications satellite. Recently, Distant Retrograde Orbits (DROs) and Near-Rectilinear Halo Orbits (NRHOs) near the Moon have been identified as motion of interest for manned and unmanned missions with a focus on operations in cislunar space. The triangular libration points, as well as …

Is Metabolism Goal-Directed? Investigating The Validity Of Modeling Biological Systems With Cybernetic Control Via Omic Data, Frank T. Devilbiss

Open Access Dissertations

Cybernetic models are uniquely juxtaposed to other metabolic modeling frameworks in that they describe the time-dependent regulation of cellular reactions in terms of dynamic "metabolic goals." This approach contrasts starkly with purely mechanistic descriptions of metabolic regulation which seek to explain metabolic processes in high resolution — a clearly daunting undertaking. Over a span of three decades, cybernetic models have been used to predict metabolic phenomena ranging from resource consumption in mixed-substrate environments to intracellular reaction fluxes of intricate metabolic networks. While the cybernetic approach has been validated in its utility for the prediction of metabolic phenomena, its central feature, …

Rearward Visibility Issues Related To Agricultural Machinery: Contributing Factors, Potential Solutions, Shawn Gregory Ehlers

Open Access Dissertations

As the size, complexity, and speed of tractors and other agricultural self-propelled machinery have increased, so have the visibility-related issues, placing significant importance on the visual skills, alertness, and reactive abilities of the operator. Rearward movement of large agricultural equipment has been identified in the literature as causing not only damage to both machine and stationary objects, but also injuries (even fatalities) to bystanders not visible to the operator. Fortunately, monitoring assistance, while not a new concept, has advanced significantly, offering operators today more options for increasing awareness of the area surrounding their machines. In this research, an attempt is …

Ultra-Thin Boron Nitride Films By Pulsed Laser Deposition: Plasma Diagnostics, Synthesis, And Device Transport, Nicholas Robert Glavin

Open Access Dissertations

This work describes, for the first time, a pulsed laser deposition (PLD) technique for growth of large area, stoichiometric ultra-thin hexagonal and amorphous boron nitride for next generation 2D material electronics. The growth of boron nitride, in this case, is driven by the high kinetic energies and chemical reactivities of the condensing species formed from physical vapor deposition (PVD) processes, which can facilitate growth over large areas and at reduced substrate temperatures. The use of optical emission spectroscopy during plasma growth provides insight into chemistry, kinetic energies, time of flight data, and spatial distributions within a PVD plasma plume ablated …

Coupled Orbit-Attitude Mission Design In The Circular Restricted Three-Body Problem, Davide Guzzetti

Open Access Dissertations

Trajectory design increasingly leverages multi-body dynamical structures that are based on an understanding of various types of orbits in the Circular Restricted Three-Body Problem (CR3BP). Given the more complex dynamical environment, mission applications may also benefit from deeper insight into the attitude motion. In this investigation, the attitude dynamics are coupled with the trajectories in the CR3BP. In a highly sensitive dynamical model, such as the orbit-attitude CR3BP, periodic solutions allow delineation of the fundamental dynamical structures. Periodic solutions are also a subset of motions that are bounded over an infinite time-span (assuming no perturbing factors), without the necessity to …

Influence Of The 3d Microenvironment On Glioblastoma Migration And Drug Response, Ruth Marisol Herrera Perez

Open Access Dissertations

Glioblastoma (GBM) is a highly invasive brain cancer characterized by poor prognosis. Despite significant efforts by the basic and clinical research community our understanding of GBM progression and recurrence has been incremental. Improvements in therapeutic response have been dismal, and GBM continues to be the deadliest tumor of the central nervous system, with patient average survival rate of 12 months. Synergistic relationships that the tumor cells establish with the brain microenvironment have been proven fundamental for successful tumor progression and maintenance. Yet, many in vitro GBM studies are performed in formats that fail to recapitulate the most essential component of …

Optimal Monitoring And Mitigation Of Systemic Risk In Lending Networks, Zhang Li

Open Access Dissertations

This thesis proposes optimal policies to manage systemic risk in financial networks. Given a one-period borrower-lender network in which all debts are due at the same time and have the same seniority, we address the problem of allocating a fixed amount of cash among the nodes to minimize the weighted sum of unpaid liabilities. Assuming all the loan amounts and cash flows are fixed and that there are no bankruptcy costs, we show that this problem is equivalent to a linear program. We develop a duality-based distributed algorithm to solve it which is useful for applications where it is desirable …

Coupled Resonator Based Wireless Power Transfer For Bioelectronics, Henry Mei

Open Access Dissertations

Implantable and wearable bioelectronics provide the ability to monitor and modulate physiological processes. They represent a promising set of technologies that can provide new treatment for patients or new tools for scientific discovery, such as in long-term studies involving small animals. As these technologies advance, two trends are clear, miniaturization and increased sophistication i.e. multiple channels, wireless bi-directional communication, and responsiveness (closed-loop devices). One primary challenge in realizing miniaturized and sophisticated bioelectronics is powering. Integration and development of wireless power transfer (WPT) technology, however, can overcome this challenge.

In this dissertation, I propose the use of coupled resonator WPT for …

Energy Efficiency In Data Collection Wireless Sensor Networks, Miquel Andres Navarro Patino

Open Access Dissertations

This dissertation studies the problem of energy efficiency in resource constrained and heterogeneous wireless sensor networks (WSNs) for data collection applications in real-world scenarios. The problem is addressed from three different perspectives: network routing, node energy profiles, and network management. First, the energy efficiency in a WSN is formulated as a load balancing problem, where the routing layer can diagnose and exploit the WSN topology redundancy to reduce the data traffic processed in critical nodes, independent of their hardware platform, improving their energy consumption and extending the network lifetime. We propose a new routing strategy that extends traditional cost-based routing …

Direct Drug Screening And Lipid Profiling Using Ambient Mass Spectrometry, Yuan Su

Open Access Dissertations

Mass spectrometry (MS) stands in an outstanding position in analysis of biological specimens owing to its abundant structural information, high accuracy, incomparable sensitivity, high speed, and the large variety of its applications. The ion source, an instrumental part for converting the analyte into ions, has played an important role in analyzing biological specimens by MS. However, the performance of conventional spray-based ionization methods always suffers from chemical interferences derived from complex biological matrices. A series of sample extraction, purification, and separation steps is required before the ionization, so as to ensure excellent performance of MS analysis. In order to simplify …

Advancing Multiple Model-Based Control Of Complex Biological Systems: Applications In T Cell Biology, Jeffrey P. Perley

Open Access Dissertations

Activated CD4+ T cells are important regulators of the adaptive immune response against invading pathogens and cancerous host cells. The process of activation is mediated by the T cell receptor and a vast network of intracellular signal transduction pathways, which recognize and interpret antigenic signals to determine the cell's response. The critical role of these early signaling events in normal cell function and the pathogenesis of disease ultimately make them attractive therapeutic targets for numerous autoimmune diseases and cancers.

Scientists increasingly rely on predictive mathematical models and control-theoretic tools to design effective strategies to manipulate cellular processes for the advancement …

Characterization Of Pool Boiling Heat Transfer From Porous-Coating-Enhanced Surfaces, Suchismita Sarangi

Open Access Dissertations

Development of techniques for enhancement and optimization of thermal management technologies has been a highly active area of research in recent decades in response to the rapid emergence of compact, high-power electronic systems. Immersion cooling by boiling is one of the preferred methods for high power density applications, due to its passive nature and high heat transfer coefficients obtained. Pool boiling heat transfer has been extensively studied in recent decades to understand the inherent mechanisms yielding the high heat transfer rates, as well as to further enhance the heat transfer by simple modifications or additions to existing approaches. This thesis …

Microgalvanic Corrosion Behavior Of Cu-Ag Active Braze Alloys Investigated With Skpfm, Armen Kvryan, Kari Livingston, Corey M. Efaw, Kyle Knori, Brian J. Jaques, Paul H. Davis, Darryl P. Butt, Michael F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

The nature of microgalvanic couple driven corrosion of brazed joints was investigated. 316L stainless steel samples were joined using Cu-Ag-Ti and Cu-Ag-In-Ti braze alloys. Phase and elemental composition across each braze and parent metal interface was characterized and scanning Kelvin probe force microscopy (SKPFM) was used to map the Volta potential differences. Co-localization of SKPFM with Energy Dispersive Spectroscopy (EDS) measurements enabled spatially resolved correlation of potential differences with composition and subsequent galvanic corrosion behavior. Following exposure to the aggressive solution, corrosion damage morphology was characterized to determine the mode of attack and likely initiation areas. When exposed to 0.6 …

Brain Tumor In A Dish: Glioma/Astrocyte Co-Cultures As A Model For In Vitro Studies, Erin Eickman, Christina Wilson, Srivatsan Kidambi

UCARE: Research Products

This study seeks to engineer an in vitro co-culture model to elucidate the role of glioma-astrocyte interactions on molecular changes in the tumor microenvironment. The use of patterned co-cultures created with polyelectrolyte multilayers and micromolding in capillaries will allow tthe investigation of cell-cell communication. This study will lead to better understanding of the role of healthy cells in cancer progression and potential treatment options.

Circle Of Willis Model For Transcranial Doppler Ultrasound Training, Conner J. Beyersdorf, Ben Hage, Greg Bashford

UCARE: Research Products

Transcranial Doppler (TCD) ultrasound is a technique involving the use of high frequency transmitters to measure intracranial blood flow. The brain is supplied by blood in an arterial anastomosis called the Circle of Willis. Using TCD ultrasound on the circle is difficult and requires practice and teaching. A functional model of the Circle of Willis could prove to be a valuable teaching tool. Through the use of AutoCAD and 3D printing software, an anatomically accurate model was created and set in gelatin phantom inside of a plastic skull. Milk was pumped through the model with a peristaltic pump to simulate …

Flying By Fire: Making Controlled Burns Safer For Humans And Uavs, Rebecca Horzewski, Carrick Detweiler

UCARE: Research Products

A temperature sensing circuit board was developed that will allow Nimbus Lab's controlled burn starting UAV to react to the temperatures around it.

Exploring Oculomotor Trends In Collegiate Athletes, Brett Whorley, Julie A. Honaker

UCARE: Research Products

Collaborative efforts to improve athlete safety without significantly hindering the rules of the games aim to develop a novel system to better measure and diagnose concussions. Provided that common signs of concussions include blurred vision, distant gaze, and dizziness, the Dizziness and Balance Disorders Lab at UNL believes that the simple oculomotor exam studied in this project may be applied to this procedure. Within the broader goal to better understand the causes, signs, symptoms, and prognosis of concussions, researchers desired to further investigate the results of this oculomotor test. The aim was to identify and interpret correlations between collegiate athlete …

Drag Reduction Using Femtosecond Laser Surface Processing: Experimental Setup, Derek Wallin, Henry Ems, Craig Zuhlke, Dennis R. Alexander, George Gogos, Sidy Ndao

UCARE: Research Products

The experimental setup for developing a system to test the drag effects of different superhydrophorbicities. This is used to revise the current Moody Chart and redefine fluid drag in a pipe.

Fluid drag reduction is important in many applications such as reducing the power requirement to pump a fluid through a channel or pipe. The Center for Electro-Optics and Functionalized Surfaces (CEFS) at the University of Nebraska – Lincoln uses a femtosecond laser to functionalize 304 stainless Steel to become superhydrophilic or superhydrophobic The Processing produces microscale and nanoscale surface roughness that when treated with siloxanes becomes superhydrophobic. Small vortices …

Investigation Of A Nanoparticle Delivery System For Micronutrients In Corn, Zully Perez Sierra, Zachary P. Stewart, Hendrik J. Viljoen

UCARE: Research Products

Pheroid Nanoparticle Delivery System1 • Cost effective for plant applications • Safe – multi-lamellar lipid system derived mostly from soybeans • Versatile – payloads delivered range from micronutrients to antibiotics Micronutrient Deficiency • Caused by the immobility of micronutrients through the plant. • Leads to malnutrition children in poor countries2 • As fertilizers deliver nutrients, only small percentage obtained by plant. Purpose of Nanoparticle Delivery System • Increase plant micronutrient content and yield • Reduces the effects of run-of, overuse and pollution Other Nano-Fertilizer Trials • Desert plant results – in a foliar application versus irrigation application, the foliar nano-fertilizer …

Growth Of Ws2 Thin Photovoltaic Films, Matthew J. Hilfiker, Aaron Ediger, Natale Lanno

UCARE: Research Products

Through research for a material that is low cost, earth abundant, and highly efficient, Tungsten Sulfide (WS₂) has been identified as a promising solution. From literature, it has been shown that WS₂ possesses a band gap of 1.9 eV, which is ideal for a top layer heterostructure cell. While this is a favorable value, other properties needed to understand its value as a photovoltaic material are unknown. Through research, WS₂ films will be grown through a sputtering deposition process and electrical characterization measurements will be performed to study these missing properties.

Engineering Outreach Education Through Social Media, Katie E. Meiergerd, Dagen Valentine, Jennifer R. Keshwani, Bradley Barker

UCARE: Research Products

Familiarizing teachers and educators with Engineering and other related STEM fields is crucial in educating students, so ensuring teachers with access to these resources is important. The objective of this work is to identify ways to use social media to provide support to K – 12 educators interested in implementing engineering education with their students.

Development Of A Robust Setup For The Study Of Wetting Characteristics Of Low Melting Point Metals, John D. Casias, Ethan Allan Davis, Sidy Ndao

UCARE: Research Products

• Energy use is very inefficient

• Approx. 60% rejected mostly in the form of waste heat

• Low melting point metals are promising for applications in thermal energy management, conversion, and storage

Ionic Driven Embedment Of Hyaluronic Acid Coated Liposomes In Polyelectrolyte Multilayer Films For Local Therapeutic Delivery, Stephen Lawrence Hayward, David Francis, Matthew J. Sis, Srivatsan Kidambi

UCARE: Research Products

The ability to control the spatial distribution and temporal release of a therapeutic remains a central challenge for biomedical research. Here, we report the development and optimization of a novel substrate mediated therapeutic delivery system comprising of hyaluronic acid covalently functionalized liposomes (HALNPs) embedded into polyelectrolyte multilayer (PEM) platform via ionic stabilization. The PEM platform was constructed from sequential deposition of Poly-LLysine (PLL) and Poly(Sodium styrene sulfonate) (SPS) “(PLL/SPS)4.5” followed by adsorption of anionic HALNPs. An adsorption affinity assay and saturation curve illustrated the preferential HALNP deposition density for precise therapeutic loading. (PLL/SPS)2.5 capping layer on top of the deposited …

Exploring Large-Scale Parameterization Of Irrigation In The Northern High Plains, Mitch Maguire, Daniel Rico, Katherine Smith, Francisco Munoz-Arriola

UCARE: Research Products

Research Question – Objective - Hypothesis

How does irrigation respond to the demands of Crop Irrigation Requirements under extreme hydrometeorological events?

Implement a parameterization of irrigation into the land surface hydrology model VIC.

Changes in evapotranspiration (ET) will be more conspicuous during dry years, highlighting the limiting role of soil moisture in the model.

Ethanol Based Foamed Asphalt As Potential Alternative For Low Emission Asphalt Technology, Mohd Rosli Mohd Hasan, Zhanping You

Michigan Tech Publications, Part 1

Foamed asphalt typically relies on water as a foaming agent because water becomes gaseous at elevated temperatures, generating numerous tiny bubbles in the asphalt and causing spontaneous foaming. In this study, ethanol was used as a potential alternative to water as a foaming agent. Ethanol is expected to be a physical blowing agent in the same manner as water, except it requires less energy to foam due to its 78 °C boiling point. This study compares the performance of water and ethanol as foaming agents through the measurements of rotational viscosity, the reduction in temperature during foaming, and volatile loss. …

Estimating River Discharge Using Multiple-Tide Gauges Distributed Along A Channel, Hamed R. Moftakhari, David A. Jay, Stefan Talke

Civil and Environmental Engineering Faculty Publications and Presentations

Reliable estimation of freshwater inflow to the ocean from large tidal rivers is vital for water resources management and climate analyses. Discharge gauging stations are typically located beyond the tidal intrusion reach, such that inputs and losses occurring closer to the ocean are not included. Here, we develop a method of estimating river discharge using multiple gauges and time-dependent tidal statistics determined via wavelet analysis. The Multiple-gauge Tidal Discharge Estimate (MTDE) method is developed using data from the Columbia River and Fraser River estuaries and calibrated against river discharge. Next, we evaluate the general applicability of MTDE by testing an …

Long-Term Effectiveness Of Radar Speed Display Signs In A University Environment, Michael R. Williamson, Ryan N. Fries, Huaguo Zhou

SIUE Faculty Research, Scholarship, and Creative Activity

Vehicular speeds are of particular interest in areas with a high number of pedestrians due to the fact that 14-percent of all fatal crashes involve pedestrians. This study investigated the effect of a radar speed display sign placed for an extended period of time, at a location frequented by law enforcement on a road segment entering a university campus with a high number of pedestrians and vehicle speed violations. The statistical analysis included a comparison between AM peak, PM peak, and midday speeds collected one year apart. The data suggested that radar speed display signs can remain effective over a …