Digital Commons Network^™

Quantification Of Tumor Biophysical Heterogeneity Through Mechanical And Ultrastructural Analysis., Bradley James Mahaffey

Electronic Theses and Dissertations

Glioblastoma (GBM) is a highly invasive, aggressive brain cancer that carries a median survival of 15 months. This poor prognosis is due, in part, to its resistance to standard therapeutic intervention. Recent studies have demonstrated that tumor heterogeneity plays a critical role in facilitation therapy resistance by mediating tumor adaptation through microenvironmental cues. Efforts to describe these microenvironmental differences may aid in the development of strategies to combat resistance. GBM can be separated into two distinct regions – a core and a rim, which are thought to drive specific aspects of tumor evolution. The core is proliferative as evidenced by …

Investigating Mems Devices In Flow Conditions Relevant To Flow-Through Systems., Mohammad Shafquatul Islam

Electronic Theses and Dissertations

Advancements in microscale actuating technologies has substantially expanded the possibilities of interacting with the surrounding environment. Microstructures that deflect in response to mechanical forces are one of the largest application areas of microelectromechanical systems (MEMS). MEMS devices, functioning as sensors, actuators, and support structures, find applications in inertial sensors, pressure sensors, chemical sensors, and robotics, among others. Driven by the critical role of catalytic membrane reactors, this dissertation aims to evaluate enzyme activity on polymeric membranes and explore how fabrication methods from the field of Electrical and Computer Engineering (ECE) can incorporate sensing and actuation into these porous surfaces. Toward …

Design, Fabrication, And Integration Of Robotic Skin Sensors For Human Robot Interaction., Olalekan Olakitan Olowo

Electronic Theses and Dissertations

Enhancing physical human-robot interaction in modern robotics relies on refining the tactile perception of robot skin sensors. This research focuses on crucial aspects of the development process, including fabrication techniques, miniaturization, and integration for a more efficient collaborative human-robot interface. The fabrication process of robot skin sensors, designed to mimic human skin, is explored both within and outside cleanroom environments. An enhanced technique is presented to increase fabrication yield and create more miniaturized sensor designs with feature sizes in the tens of microns. These sensors function as piezoresistive arrays using organic polymers like PEDOT: PSS as the pressure-sensing medium. Various …

A Bioinspired Astrocyte-Derived Coating Promotes The In Vitro Proliferation Of Human Neural Stem Cells While Maintaining Their Stemness, Andrea C. Jimenez-Vergara, Jacob Avina, Travis Jackson Block, Anne Sheldrake, Carson Koch, Anna Gonzalez, Jennifer Steele, Ana M. Díaz-Lasprilla, Dany J. Munoz-Pinto

Engineering Faculty Research

The repair of neuronal tissue is a challenging process due to the limited proliferative capacity of neurons. Neural stem cells (NSCs) can aid in the regeneration process of neural tissue due to their high proliferation potential and capacity to differentiate into neurons. The therapeutic potential of these cells can only be achieved if sufficient cells are obtained without losing their differentiation potential. Toward this end, an astrocyte-derived coating (HAc) was evaluated as a promising substrate to promote the proliferation of NSCs. Mass spectroscopy and scanning electron microscopy were used to characterize the HAc. The proliferation rate and the expression of …

Statistical And Deep Learning Models For Reference Evapotranspiration Time Series Forecasting: A Comparison Of Accuracy, Complexity, And Data Efficiency, Arman Ahmadi, Andre Daccache, Mojtaba Sadegh, Richard L. Snyder

Civil Engineering Faculty Publications and Presentations

Reference evapotranspiration (ETo) is an essential variable in agricultural water resources management and irrigation scheduling. An accurate and reliable forecast of ETo facilitates effective decision-making in agriculture. Although numerous studies assessed various methodologies for ETo forecasting, an in-depth multi-dimensional analysis evaluating different aspects of these methodologies is missing. This study systematically evaluates the complexity, computational cost, data efficiency, and accuracy of ten models that have been used or could potentially be used for ETo forecasting. These models range from well-known statistical forecasting models like seasonal autoregressive integrated moving average (SARIMA) to state-of-the-art deep learning (DL) algorithms like temporal fusion transformer …

Condition Assessment Of Reinforced Concrete Sanitary Sewer Pipelines Using Probabilistic Methods And Advanced Inspection Tools, Moein Ebrahimi

Civil Engineering Dissertations - Archive

Large sanitary sewer pipelines (SSPs) are the backbone of modern infrastructure. They carry wastewater from smaller lines to treatment plans; therefore, they are critical for public health and safety. According to the ASCE report card published in 2021, the condition rate of sanitary sewage networks in the United States is D+ (i.e., poor) (ASCE 2021). Therefore, frequent inspections of SSPs are crucial for performing a proper life cycle management strategy. New inspection technologies such as LiDAR have recently been employed for rapid condition assessment of SSPs. Because of the precision of LiDAR inspection data, it can not only measure hydraulic …

Brunet: Disruption-Tolerant Tcp And Decentralized Wi-Fi For Small Systems Of Vehicles, Nicholas Brunet

Master's Theses

Reliable wireless communication is essential for small systems of vehicles. However, for small-scale robotics projects where communication is not the primary goal, programmers frequently choose to use TCP with Wi-Fi because of their familiarity with the sockets API and the widespread availability of Wi-Fi hardware. However, neither of these technologies are suitable in their default configurations for highly mobile vehicles that experience frequent, extended disruptions. BRUNET (BRUNET Really Useful NETwork) provides a two-tier software solution that enhances the communication capabilities for Linux-based systems. An ad-hoc Wi-Fi network permits decentralized peer-to-peer and multi-hop connectivity without the need for dedicated network infrastructure. …

Deep Ocean Vehicle Applications And Modifications, Nichole "Nikki" T. Arm

Master's Theses

This project had two primary goals: (1) to explore opportunities to further a deep-ocean vehicle’s reach using alternative pressure spheres, and (2) to implement an existing deep-ocean vehicle (lander) in active scientific research.

I gained a greater understanding of the limitations and design choices made for existing pressure spheres using Finite Element Analysis (FEA). My simplified FEA model predicted sphere failure for the existing 30% Fiber Glass 70% Nylon injection molded spheres at an external pressure of 3,954psi or 2,690m ocean-depth (only a 7.38% error compared to the tested minimum failure depth), so I determined it a valid model. I …

Nanobubble Technology For The Removal Of Mib And Geosmin From Drinking Water, Meryem Soyluoglu

All Dissertations

The presence of taste and odor (T&O) compounds in drinking water has been historically a major challenge for water utilities. They are difficult to remove using conventional water treatment processes, a combination of coagulation, flocculation, sedimentation, filtration, and chlorination. However, activated carbon (AC) adsorption, advanced oxidation processes, and biofiltration can be effective. The seasonal nature of T&O events makes it difficult to justify installing dedicated treatment technologies. Additionally, incorporating these technologies into existing water treatment plants can be expensive and require significant upgrades. Therefore, water utilities are always interested in exploring new approaches to minimize the occurrence and removal of …

Determining The Effects Of Glycocalyx Modifications On The Electrophysical Properties Of Human Mesenchymal Stem Cells, Rominna E. Valentine Ico

Electronic Theses, Projects, and Dissertations

Human mesenchymal stem cells (hMSCs) have gained popularity in clinical trials due to their multipotent differentiation characteristics, ability to secrete bioactive molecules, migrate into diseased or damaged tissues, and their immunosuppressive properties. HMSC cultures are heterogeneous, containing stem cells, partially differentiated progenitor cells, and fully differentiated cells. One of the major challenges with hMSCs therapeutic potential is the inability to select specific cell subpopulations due to an insufficient number of biomarkers. Often the biomarkers used, like those for fluorescence-activated cell sorting, are not sufficient to define hMSCs because they overlap with other cell types. Consequently, there is a need to …

Radiation Exposure Calibration Of The Al2o3:C With Radium-226 And Cesium-137 Using The Osl Method, Selma Tepeli Aydin

All Theses

Optically stimulated luminescence (OSL) dosimetry was utilized to calibrate Al₂O₃:C powder dosimeters, available commercially as the nanoDot® from Landauer Inc., and compare the dosimeter response to radium-226 (²²⁶Ra) and cesium-137 (¹³⁷Cs). The signal from the OSL was quantified using a microSTARii^® OSL reader also produced by Landauer Inc. Dose-response curves were developed for ²²⁶Ra and ¹³⁷Cs experiments (5 dosimeters each) at thirteen absorbed doses. Individual dosimeter response was tracked by serial number. Linear regression analysis was performed to determine if there were significant differences between the intercepts of the …

Exploring The Potential Of Tesla Valve For Filtering And Sorting Microscale Active Swimmers: A Computational Study, Ariel Rogers, Zhiyao He, Yong Wang

Physics Faculty Publications and Presentations

It is well-known that a Tesla valve allows fluids to flow unidirectionally without moving parts; however, how Tesla valves interact with active matters and the potential applications of Tesla valves in biology remain largely unexplored. Here, we present a computational study on the potential use of Tesla valves for filtering and sorting microscale active swimmers such as bacteria. We investigated the behavior of microscale swimmers passing through the Tesla valve at different linear and angular velocities using numerical simulations and quantified the diodicity of the Tesla valve for active swimmers. Our results demonstrate that the Tesla valve can effectively filter …

Vehicle-Bridge Interaction Simulation And Damage Identification Of A Bridge Using Responses Measured In A Passing Vehicle By Empirical Mode Decomposition Method, Shohel Rana, Md. Rifat Zaman, Md. Ibrahim Islam Ifty, Seyedali Mirmotalebi, Tahsin Tareque

Civil Engineering Faculty Publications

To prevent early bridge failures, effective Structural Health Monitoring (SHM) is vital. Vibration-based damage assessment is a powerful tool in this regard, as it relies on changes in a structure’s dynamic characteristics as it degrades. By measuring the vibration response of a bridge due to passing vehicles, this approach can identify potential structural damage. This dissertation introduces a novel technique grounded in Vehicle-Bridge Interaction (VBI) to evaluate bridge health. It aims to detect damage by analyzing the response of passing vehicles, taking into account VBI. The theoretical foundation of this method begins with representing the bridge’s superstructure using a Finite …

Enhanced Fabrication Of Microdroplet Generator Nozzle Arrays: Optimizing Koh Etching For Microfluidic Applications, Hongyu Bai

McKelvey School of Engineering Graduate Student Theses & Dissertations

Ultrasonic microdroplet generators are useful devices with broad applications ranging from aerosolized drug delivery to three-dimensional (3D) printing-based additive manufacturing. One such technology comprises a microfabricated array of nozzles with droplet production driven by a piezoelectric transducer. The present study focuses on refining a critical fabrication step, anisotropic wet etching of pyramidal nozzles using a basic potassium hydroxide (KOH) solution. Given the integral role of nozzle geometry in device operation, high-precision techniques including Reactive Ion Etching (RIE), Deep Reactive Ion Etching (DRIE), and KOH wet etching were employed. A tapering geometry is preferred for acoustic wave focusing and efficient droplet …

Comprehensive Analysis Of The Effects Of Superplasticizer Variation On The Workability And Strength Of Ready-Mix Concrete, Tahsin Tareque, Fahmid Tousif, Mirza Addaito Billah, Abdullah Al Masum Jabir, Seyedali Mirmotalebi

Civil Engineering Faculty Publications

This experimental study aims to examine the influence of many crucial parameters on the workability and compressive strength of Ready-Mix Concrete (RMC). The study utilized two distinct varieties of superplasticizers obtained from the local market. The fine aggregates utilized in this study were sourced from Sylhet sand, whereas the coarse aggregates were comprised of boulder crushed stone chips. The experimental procedures adhered to the requirements outlined by ASTM. A comprehensive investigation was conducted on a range of concrete compositions that used diverse chemical admixtures. The slump test was performed at regular intervals of 15 minutes until the slump value reached …

Atmospheric-Moisture-Induced Polyacrylate Hydrogels For Hybrid Passive Cooling, Roisul Hasan Galib, Yanpei Tian, Yue Lei, Saichao Dang, Xiaole Li, Arief Yudhanto, Gilles Lubineau, Qiaoqiang Gan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Heat stress is being exacerbated by global warming, jeopardizing human and social sustainability. As a result, reliable and energy-efficient cooling methods are highly sought-after. Here, we report a polyacrylate film fabricated by self-moisture-absorbing hygroscopic hydrogel for efficient hybrid passive cooling. Using one of the lowest-cost industrial materials (e.g., sodium polyacrylate), we demonstrate radiative cooling by reducing solar heating with high solar reflectance (0.93) while maximizing thermal emission with high mid-infrared emittance (0.99). Importantly, the manufacturing process utilizes only atmospheric moisture and requires no additional chemicals or energy consumption, making it a completely green process. Under sunlight illumination of 800 W …

A Framework Of Flow Models For The Development And Testing Of Cardiovascular Devices, Megan Laughlin

Graduate Theses and Dissertations

Cardiovascular disease (CVD) is the leading cause of death worldwide and its treatment continues to improve due to the advancement of innovative cardiovascular medical devices. In vitro and in silico models serve to replicate the in vivo environment for the development and testing of these devices prior to using animals for testing, and eventually humans in clinical trials. However, limitations related to these models exist in multiple areas including general, cardiac, and venous applications. Specifically, current gaps have been identified with customizable, tissue-mimicking phantoms (general), 2D Blood Speckle Imaging (BSI) (cardiac) and a bioprosthetic venous valve (venous). This dissertation focuses …

3d Printed Microdialysis-Based Microsampling Probes, Patrick Pysz

Graduate Theses and Dissertations

This work will show the development of a fully 3D printed device platform in which a complex microsampling probe geometry is fabricated in a simple two-step process. This process includes the combination of 2-photon polymerization (2PP) and masked-stereolithography (MSLA). The cutting edge neurotechnology needed to monitor brain internal communication and will require multiple sensing modalities including temperature, pressure, electrophysiological, and optogenetics. Microsampling is an integrally important function for any future biosensing device platform as it allows for chemical delivery and unparalleled specificity through offline analysis of collection samples. Stereolithography (SLA) 3D printing has emerged as a powerful fabrication method capable …

Assessing The Effectiveness Of Nuclear Security Training And Education In Ghana, Michael Nii Sanka Ansah, Boris Stepanov Pavlovich, Paul Atta Amoah, David Okoh Kpeglo, Simon Adu, Bright Kwame Afornu

International Journal of Nuclear Security

Growing attention is being given to nuclear power across several African countries, including in Ghana. The world is depending on nuclear energy as a reliable and efficient means of energy generation. Ghana as a country is developing nuclear energy; thus, equal attention must be directed toward nuclear safety and security. Ghana is gradually developing interest in and is devoting substantial required resources to educating and training on nuclear security to meet the standards required by international bodies. Institutions such as the Nuclear Safety and Security Centre and the School of Nuclear and Allied Sciences of the Ghana Atomic Energy Commission …

A Wearable Fluorescence Imaging Device For Intraoperative Identification Of Human Brain Tumors, Mehrana Mohtasebi, Chong Huang, Mingjun Zhao, Siavash Mazdeyasna, Xuhui Liu, Samaneh Rabienia Haratbar, Faraneh Fathi, Jinghong Sun, Thomas A. Pittman, Guoqiang Yu

Biomedical Engineering Faculty Publications

Malignant glioma (MG) is the most common type of primary malignant brain tumors. Surgical resection of MG remains the cornerstone of therapy and the extent of resection correlates with patient survival. A limiting factor for resection, however, is the difficulty in differentiating the tumor from normal tissue during surgery. Fluorescence imaging is an emerging technique for real-time intraoperative visualization of MGs and their boundaries. However, most clinical grade neurosurgical operative microscopes with fluorescence imaging ability are hampered by low adoption rates due to high cost, limited portability, limited operation flexibility, and lack of skilled professionals with technical knowledge. To overcome …

Development Of A Machine Learning System For Irrigation Decision Support With Disparate Data Streams, Eric Wilkening

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

In recent years, advancements in irrigation technologies have led to increased efficiency in irrigation applications, encompassing the adoption of practices that utilize data-driven irrigation scheduling and leveraging variable rate irrigation (VRI). These technological improvements have the potential to reduce water withdrawals and diversions from both groundwater and surface water sources. However, it is vital to recognize that improved application efficiency does not necessarily equate to increased water availability for future or downstream use. This is particularly crucial in the context of consumptive water use, which refers to water consumed and not returned to the local or sub-regional watershed, representing a …

In Situ Water Sensing Systems: Research On Advancements In Environmental Monitoring, Abigail Seibel

Honors Program: Senior Projects (Public)

In this work, two sensing systems were researched in order to improve in situ environmental monitoring. The first is a pH and Total Alkalinity sensor used to determine these characteristics of sea water. I explored the facets of this sensor over a 7-week internship with Dr. Ellen Briggs in her lab in summer of 2023. The second is a more holistic sensing system that reads temperature, turbidity, and pressure used for studying environmental characteristics of Alaskan bever ponds. Both systems were developed in close collaboration with scientists who are collecting data to better understand the impacts of climate change. Better …

Development Of Metaheuristic Algorithms For The Efficient Allocation Of Power Flow Control Devices, Eduardo Jose Castillo Fatule

Open Access Theses & Dissertations

No abstract provided.

Development Of A 3d Printed Conductive Biopolymer For Cardiac Tissue Engineering, Britanny Lizeth Stark

Open Access Theses & Dissertations

Cardiovascular disease (CVD) is the leading cause of death in the US, with approximately 859,000 deaths each year. The major contributor to CVD is Acute Myocardial Infarction (AMI), which causes the death of approximately 25% of the cardiomyocytes present in the left ventricle of the heart. After AMI, the adult human heart has a very limited regenerative capacity. Moreover, the electrical propagation of the myocardium is severely disrupted, making the heart more susceptible to failure and patient death. However, current pharmacological treatments do not address the loss of cardiomyocytes and the disruption of electrical propagation in the heart. Tissue engineering …

Viability Of Magnetic Nanoparticles For Magnetic Hyperthermia Cancer Therapy, Marcos Adrian Garcia

Open Access Theses & Dissertations

Over the last few decades magnetic nanoparticles have gained an extraordinary amount of attention in the science community. Their versatile use in many different research areas such as medicine, engineering and technology and many other areas has made them a popular subject. In this thesis, the synthesis of different systems of magnetic nanoparticles will be explored along with the potential use of the MNP's as viable candidates for Magnetic Hyperthermia Cancer Therapy. With values of over 200 emu/g for Iron-Silver magnetic nanoparticles with particle sizes ranging from 30-70nm and their heating properties under an AC magnetic field. As well of …

Towards A Spaceworthy Cots Graphics Processing Unit: Hardware Performance Counter Based Symptomatic Fault Detection, Antonio E. Teijeiro

Open Access Theses & Dissertations

Ionizing radiation remains an obstacle to bringing graphics processing units (GPU) to space. Since radiation-hardened GPU chips are technically infeasible at the moment, an emphasis has been placed on the adaptation of commercial-off-the-shelf (COTS) GPUs to the space domain. At present, GPU error detection methods require redundant computation. This thesis work explores the utilization of hardware performance counters, special registers useful for monitoring internal GPU hardware events, for symptom-based, lightweight error detection. Hardware performance counters are successfully utilized for the detection of anomalous single event upsets in the L0 instruction cache, the load store unit, the arithmetic and logic unit, …

Ionically Crosslinked Cellulose Nanocrystals By Metal Nitrates For The Preparation Of Stable Emulsions With Tunable Interface Properties, Joseph Batta-Mpouma, Gurshagan Kandhola, Jin-Woo Kim

Materials Science and Engineering Faculty Publications and Presentations

Biologically extracted cellulose nanocrystals (CNCs) are rod-like and amphiphilic materials with surface-exposed (hydrophilic sites) and hidden (hydrophobic sites) hydroxyl groups. These physicochemical characteristics make CNCs suitable for use as emulsifying agents to stabilize emulsions. Stable oil-in-water emulsions, using sulfated (i.e., – SO₃−) CNCs that were ionically crosslinked with alkaline-earth (i.e., Mg ²⁺) or transition-d-block (i.e., Zn ²⁺) metal cations, were developed without the use of any synthetic surfactants or prior functionalization of pure CNCs with hydrophobic molecules. Various emulsion surface properties such as interfacial tension, surface charge, surface chemistry, as well as rheology were characterized. Ionically …

The Effect Of The Number Of Hidden Layers On The Performance Of Deep Q-Network For Traveling Salesman Problem, Benzfica Hanif, Aisyah Larasati, Rudi Nurdiansyah, Trung Le

Knowledge Engineering and Data Science

The Traveling Salesman Problem (TSP) effectively represents the complex distribution issues encountered by couriers, who must carefully plan a route that includes all customer addresses while minimizing the distance traveled. As the magnitude of deliveries and the range of destinations expand, the courier's responsibility becomes progressively challenging. In this particular context, the objective of our research is to expand the existing knowledge and explore the complete capabilities of Deep Q-Network (DQN) models in order to achieve the most efficient route determination. This endeavor can potentially bring about significant changes in the courier and delivery service sector. The foundation of our …

Comparison Of Machine Learning Algorithms For Species Family Classification Using Dna Barcode, Lala Septem Riza, M Ammar Fadhlur Rahman, Yudi Prasetyo, Muhammad Iqbal Zain, Herbert Siregar, Topik Hidayat, Khyrina Airin Fariza Abu Samah, Miftahurrahma Rosyda

Knowledge Engineering and Data Science

Classifying plant species within the Liliaceae and Amaryllidaceae families presents inherent challenges due to the complex genetic diversity and overlapping morphological traits among species. This study explores the difficulties in accurate classification by comparing 11 supervised learning algorithms applied to DNA barcode data, aiming to enhance the precision of species family classification in these taxonomically intricate plant families. The ribulose-1,5-bisphosphate carboxylase-oxygenase large sub-unit (rbcL) gene, selected as a DNA barcode locus for plants, is used to represent species within the Amaryllidaceae and Liliaceae families. The experimental results demonstrate that nearly all tested models achieve accurate species classification into the appropriate …

Unraveling Water Quality Issues In The Colorado River Basin: Utilizing Remote Sensing Satellite Images, Statistical, And Machine Learning For Improved Monitoring, Godson Ebenezer Adjovu

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research was aimed at exploring innovative and cost-effective tools in understanding the spatiotemporal variability of water quality parameters in the Colorado River Basin (CRB), which includes the Colorado River and major reservoirs and lakes in the USA including Lake Mead. The river which arises in the state of Colorado and empties into the Republic of Mexico at the Gulf of California, is a source of water to seven US states and the Republic of Mexico and provides water to about 40 million people and million acres of farmlands in seven states in the western US and the Republic of …