Engineering Commons^™

In-Service Performance Evaluation Of Concrete Sloped End Treatments In Iowa, Jessica Lingenfelter

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Sloped end treatments were historically developed as low-cost, low-maintenance end treatments for rigid features like concrete barriers and bridge rails. Crash testing indicated that sloped end treatments are associated with significant instability for impacting vehicles. However, the in-service performance of these features has not been evaluated. An in-service performance evaluation (ISPE) was performed to evaluate vehicle crashes with sloped end treatments in Iowa between 2008 and 2017. Researchers generated a geographic inventory of sloped end treatment locations, reviewed crash narratives and scene diagrams for crashes near these sloped end treatments, and calculated an estimated crash rate and crash cost for …

Riveted Steel Railway Bridge Health Monitoring And Damage Detection, Ahmed Rageh

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Visual inspection is often used to assess the condition of railway bridges at discrete points in time, an approach that can be subjective and possibly unsafe. Alternatively, certain bridges have their condition assessed via the installation of a large number of sensors. These sensors can be costly to place, power and maintain. Therefore, reducing their numbers and maximizing the extracted information is of utmost importance. In addition, evaluating bridge condition from measured response can be quite challenging due to loading and environmental variations, especially when a limited number of sensors are used.

The focus of this research is to develop …

The Impact Of Electrostatic Correlations On The Electrokinetics, Elaheh Alidoosti

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this project we are interested in electrokinetics phenomenon (i.e., study of electrical charges in a liquid matter) and focus on three families of this phenomenon, dielectrophoresis, electro-osmosis and streaming current. For the first work, at concentrated electrolytes, the ion-ion electrostatic correlations effect is considered as an important factor in electrokinetics. In this project, we compute, in theory and simulation, the dipole moment for a spherical particle (charged, dielectric) under the presence of an alternating electric field using the modified continuum Poisson-Nernst-Planck (PNP) model by Bazant et al. (Phys. Rev. Lett. 106, 2011) [25]. We investigate the dependency of the …

Discrete Vortex Modeling Of Aerodynamic Flutter Of A Flat Plate With Damped Oscillations, Emma Chao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aerodynamic flutter is the unstable oscillation of a body caused by the interaction of aerodynamic forces, structural elasticity, and inertial effects induced by vortex shedding. Current models of this phenomenon require finite element analysis and extensive computational power and processing time. The purpose of this study was to develop and validate a program that is faster and more efficient than existing approaches by using the discrete vortex method (DVM). By reducing the complexities of flutter to the shedding of vortices in an inviscid model of a two-dimensional flat plate with a torsional spring constant at its center, this phenomenon can …

Material Characterization Of Fiber-Reinforced Composite Materials Under Dynamic Loading Condition, Abu Iqbal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fiber reinforced composites are light materials which exhibits great strength and stiffness. They also have good dimensional stability and impact resistance. They reduce mass and improve structural performance, so the demand for fiber reinforced composite materials increases day by day in various industries such as aeronautical, automobile and military. The analysis, design, and optimization of polymer composite materials under static loading conditions are mature fields of study. Many sources are available to find material properties and predict structural response. However, composite materials are often used in extreme environments where they are subject to shock, impact, and blast loading. Efficient computational …

Acoustic Sonolysis Of Antibiotics In Water, Natalie Pinon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Antibiotic resistance is a prominent issue in the world today. It is said by the Centers for Disease Control and Prevention that it is one of the major public health challenges we face today. Predominantly, antibiotic resistance is growing because conventional wastewater treatment processes are not able to completely break down antibiotics. As bacteria are exposed to such antibiotics, which don’t kill them due to selective pressure, they become immune and develop resistance which is a huge health concern. To prevent this from occurring, antibiotics need to be removed from hospital wastewater. Sonication is a promising technology that can be …

Abiotic, Biotic, And Bio-Enhanced Reduction Of Hexavalent Chromium, Chloroform And Co-Contaminants Using Nano-Scale Zero Valent Iron In Highly Contaminated Groundwater, Eduardo Robleto Martinez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Investigations of groundwater in a former industrial perchlorate manufacturing site have shown high contamination with perchlorate, chlorate, nitrate, hexavalent chromium (Cr (VI)), and chloroform (CF) with levels greater than 3,000, 30,000, 300, 100, and 4 mg/L, respectively. Remediation efforts using biological reduction to desired contaminant levels at this site has been challenging due to high contaminant concentrations, and high total dissolved solids (TDS). Furthermore, removal of Cr(VI) and CF in the presence of nitrate, chlorate, and perchlorate has not been examined at the contaminated site. Nano-scale Zero-Valent-Iron (NZVI) has been effective at reducing groundwater contamination both with and without bacterial …

Gen-Foam Multiphysics Model Development For Molten Salt Reactors, Jeffrey Stewart

UNLV Theses, Dissertations, Professional Papers, and Capstones

In thermal neutron spectrum Molten Salt Reactors (MSR), a graphite moderator contributes a positive reactivity value to the overall temperature reactivity coefficient of the core. When irradiated in the core, graphite undergoes dimensional changes which depend on the neutron spectrum. The graphite lifespan is a limiting parameter in MSR designs; it correlates strongly with the graphite’s dimensional changes. Multi-physics modeling is necessary to evaluate the graphite thermal and mechanical responses to the MSR core conditions. To assess graphite dimensional changes associated with irradiation, a computational model was developed upon the foundation of the multi-physics solver, GeN-Foam. Irradiated graphite dimensional change …

Front-End Cmos Transimpedance Amplifiers On A Silicon Photomultiplier Resistant To Fast Neutron Fluence, Mario Valles Montenegro

UNLV Theses, Dissertations, Professional Papers, and Capstones

Radiation hard electronics are indispensable in providing reliable diagnostics in fast radiation detection, which are necessary for new fundamental science research. In the case of radiation detection, transimpedance amplifiers are needed to magnify low photodetector signals to readable levels reliably. This thesis investigates a way to design a transimpedance CMOS-front-end transimpedance amplifier (TIA) as a first stage front-end amplifier. The TIA is to be mounted on silicon photomultiplier (SiPM), as a photodetector in fast neutron scintillation experiments capable of sustaining up to 10^15 n/cm of fast neutrons in the range of 0.1 to 20 MeV. The proposed TIA was designed …

Public-Private Partnership Contract Framework Development And Project Performance Analysis Compared To Design-Build In The Us Highway Projects, Medya Fathi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction projects can be delivered through various approaches; nevertheless, all practitioners and involved parties have a mutual goal, which is completing the project within the original scope, defined budget, and schedule. Reviewing the literature on public-private partnership (PPP), many efforts have been made covering different research areas, including policies, risks, roles and responsibilities, and finance. However, a study involving the development of a framework for PPP contracts, and quantitative assessment of project performance associated with PPP highway projects in the US is lacking. Therefore, this research fills such a noticeable gap in the body of knowledge on the PPP delivery …

High Salinity, High Concentration Perchlorate Reduction In The Presence Of Hexavalent Chromium, Nitrate, And Chlorate, Nicole Martin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Perchlorate is a chemically stable anion which was used as an oxidizer in rocket propellant and explosives throughout the 1950’s and 1960’s. While natural sources of perchlorate exist, perchlorate in the environment is primarily a result of contamination from anthropogenic processes. Perchlorate contamination has now been identified in at least 45 states and is hazard to human health due to perchlorate’s ability to interfere with uptake of iodine in the thyroid gland. One of the most common and cost effective treatment methods for perchlorate remediation is biological reduction—utilizing bacteria to enzymatically reduce perchlorate into chloride and oxygen.

The purpose of …

3d Parametric Hand To Improve Prosthetic Hand Functionality, Maria C. Gerardi

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of prosthetics can significantly enhance an individual’s standard of living, not only offering functional advantages but psychological advantages as well. Unfortunately for children with upper limb reduction, options are limited and rejection rates are high due to a multitude of reasons including discomfort and poor functionality. This study proposes a new parametric 3D design model (Parametric Hand) with an adjustable thumb that can be easily manipulated to the uniqueness of an individual. The Parametric Hand was evaluated, both qualitatively and quantitatively, against the Flexy-Hand 2, a commonly used prosthetic hand. The results showed insignificant differences in all testing …

The Dynamic Control Platform: Reinventing The Wheel, One Leg At A Time, Angel Javier Solis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Upright bipedal walking is a complex balance of forces and actions that is almost taken for granted. How this system is modeled, how it affects a prosthesis, and how it can be implemented in the real world are topics that the proposed Dynamic Control Platform aims to address.

The Dynamic Control Platform (DCP) is a bipedal robot designed to test bio-inspired control algorithms with the aim to smooth out the walking experience for prosthetic legs. The main control paradigm that the DCP centers on the principle of orthogonal constraint, which aims to enforce a perpendicular relationship between the center of …

Mathematical Characterization Of A Microfluidic Ultrasound Driven Transfection Device., Chris J. Holton

Electronic Theses and Dissertations

The objective of this thesis is to develop a mathematical model characterizing the behavior of a microfluidic sonoporation device in order to understand how standing wave conditions influence molecular delivery to cells and determine whether the model predicts device performance. A prior model based on an ultrasonic separation cell that uses standing waves to separate particles is adapted for translation to the microfluidic device. This study generates data on acoustic pressure profiles across the cell as well as identifying optimal driving frequencies. This model is validated and the equations and methods for developing this model are translated to the microfluidic …

Addition Of Fermentation Experiment To Unit Operations Laboratory, Jeremy T. Rone

Electronic Theses and Dissertations

With the growth of the distillery and brewery industries and the potential jobs created for chemical engineers, it is imperative to equip the chemical engineering graduates from the University of Louisville with knowledge of bioreaction kinetics and experience in performing calculations to solve for concentration profiles and reaction rates. To accomplish this, it is recommended to add a fermentation experiment to the Unit Operations Laboratory II course.

Four groups of students from the Spring 2020 Unit Operations Laboratory II course performed the fermentation experiment. They were able to successfully complete all lab requirements as well as analyze the results and …

Effects Of Design Autonomy On The Flow Experience, Antonio F Coriano

Electronic Theses and Dissertations

Most modern workplace settings are laden with operating procedures aimed at standardizing action in the name of efficiency. The cost of this standardization is the autonomy of the operator. Mihaly Csikszentmihalyi stated the problem concisely in his 1975 work Beyond Boredom and Anxiety “… [M]ost of the institutions that take up our time…are organized around the assumption that serious work is grim and unpleasant. Because of this assumption, most of our time is spent doing unpleasant things”. An experiment was created to study and better understand how to redress this harmful situation. Sixteen subjects were given a SolidWorks computer-aided design …

Labview Improvements And Equipment Redesign Of Unit Operations Distillation Column, Madalyn S Wead

Electronic Theses and Dissertations

Unit Operations labs are important tools to provide hands-on learning with various chemical processes. The distillation lab experiment allows students to connect equations and definitions from textbooks to the physical processes of distillation as they occur. LabVIEW was the software development tool used to create a program to control the distillation column from startup to shutdown. Improvements were made to both the distillation process equipment and the LabVIEW code to create a more interactive lab experience, enhance students’ conceptual understanding of distillation, and prepare students for their future career as chemical engineers.

Equipment addressed included non-linear valves, malfunctioning temperature and …

Determination Of Selenite And Selenate In Wet Flue Gas Desulfurization Process Water Through Ic-Icp-Ms And Hg-Icp-Aes, Samuel Anthony Kelty

Electronic Theses and Dissertations

During coal-fired electric power production, coal bound elemental selenium is released into the gas phase and oxidized to selenite and selenate in the wet flue gas desulfurization (WFGD) unit. Selenite and selenate solubilize in the WFGD process water. A process water system at a coal fired power plant contributes to environmental regulation compliance by removing the selenium species from WFGD process water. A selenium speciation method was developed for the purpose of better monitoring the selenium species present in the “treated” process water and to aid the process water system in meeting compliance with the Environmental Protection Agency’s Effluent Limitation …

Joint Location And Inventory Models And Algorithms For Deployment Of Hybrid Electric Vehicle Charging Stations., Jie Zhang

Electronic Theses and Dissertations

This thesis describes a study of a novel concept of hybrid electric vehicle charging stations in which two types of services are offered: battery swapping and fast level-3 DC charging. The battery swapping and fast-charging service are modeled by using the M/G/s/s model and the M/G/s/$\infty$ model, respectively. In particular, we focus on the operations of joint battery swapping and fast charging services, develop four joint locations and inventory models: two for the deployment of battery swapping service, two for the deployment of hybrid electric vehicle charging service. The first model for each deployment system considers a service-level constraint for …

Optimization And Simulation Models To Improve Access To Organ Transplantation In The United States., Fatemeh Karami

Electronic Theses and Dissertations

Organ allocation in the U.S. is administrated by the United Network of Organ Sharing (UNOS). UNOS’s mission is to ensure fair and equitable allocation of organs as stated in the Code of Federal Regulations, which reads "neither place of residence nor place of listing shall be a major determinant of access to transplant". Despite the regulations, there has been endless controversy surrounding the disparity in access to organ transplants. In this context, the primary research goal in this dissertation was to reduce geographic disparity in access to transplants in the U.S., with a focus on heart and kidney transplants. To …

Materials-Processing Relationships For Metal Fused Filament Fabrication Of Ti-6al-4v Alloy., Paramjot Singh

Electronic Theses and Dissertations

Additive manufacturing (AM) is at the mainstream to cater the needs for rapid tooling and small-scale part production. The metal AM of complex geometries is widely accepted and promoted in the industry. While several metal AM technologies exist and are matured to a level where expectation in terms of design and properties are possible to realize. But the metal AM suffers from the heavy expense to acquire equipment, isotropic property challenges, and potential hazards to work with loose reactive metal powder. With this motivation, the dissertation aims to develop the fundamental aspects to print metal parts with bound Ti-6Al-4V powder …

Impact Of Magnetocaloric Material Properties On Performance Of A Magnetocaloric Heat Pump., Michael G. Schroeder

Electronic Theses and Dissertations

In the field of magnetocaloric heat pumps much research has been performed around machine design and theoretical machines, but little has been researched around practical problems such as variability in material properties. The present work defines a simulation tool that has been proven with experimental data. Magnetocaloric material cascades were statistically analyzed and parameterized, such that they could be recreated parametrically using a split Lorentz function with normally distributed parameters. Correlated curve-defining values with standard deviations were used as input into the simulation tool to determine the effect of variation on cooling heat pump performance for a household refrigerator application. …

Influences Of Material Extrusion Additive Manufacturing (Meam) Parameters And Additives On Polyvinylidene Fluoride (Pvdf) Properties., Niknam Momenzadeh

Electronic Theses and Dissertations

Beyond the beneficial characteristics of smart polymers associated with all polymers such as flexibility and cost fabrication, smart materials exhibit multifunctional behaviors. The prospect of integrating structural and sensing/actuation capabilities into a single structure gives design engineers an ability to innovate highly novel, multi-functional creations. Polyvinylidene Fluoride (PVDF) is one of the widely used multi-functional materials which offers a variety of desirable material properties. It possesses exceptional chemical and UV resistance, biocompatibility, low processing temperature and affordable price making it a competitive choice for many commercial applications. In addition, among polymers, PVDF is simply the most dominant piezoelectric polymer. On …

Computational Techniques In Medical Image Analysis Application For White Blood Cells Classification., Omar Dekhil

Electronic Theses and Dissertations

White blood cells play important rule in the human body immunity and any change in their count may cause serious diseases. In this study, a system is introduced for white blood cells localization and classification. The dataset used in this study is formed by two components, the first is the annotation dataset that will be used in the localization (364 images), and the second is labeled classes that will be used in the classification (12,444 images). For the localization, two approaches will be discussed, a classical approach and a deep learning based approach. For the classification, 5 different deep learning …

Selective Laser Melting 17-4 Ph Stainless Steel And The Effect Of Varied Thermal Treatments On Fatigue Behavior., Sean Daniel Dobson

Electronic Theses and Dissertations

Fatigue failure is the leading source of loss in industry. In order for new means of manufacturing to move towards mainstream use a complete understanding of material and mechanical behavior must be gained. This endeavor seeks to aide in that task by observing the fatigue behavior of selective laser melting (SLM) additive manufacturing (AM) specimens and the effect of differing thermal treatment conditions for an optimized AM process. Stainless steel 17-4 PH specimens were fabricated using SLM AM and thermally treated to three conditions: as-built, solutionized and hardened, and direct hardened. These specimens were characterized for material (powder quality, density, …

Construction-Ready Digital Terrain Models, Rachel Catchings, Steven Waddle, Hala Nassereddine, Gabriel B. Dadi, Makram Bou Hatoum, Walter Johnson

Kentucky Transportation Center Research Report

Since 2009, Kentucky has made its 3D design data available as a supplemental reference to bidders through the project delivery process. This research discusses methods for ensuring electronic engineering data (EED) — and specifically the proposed digital terrain model (DTM) — support modern construction management methods at the Kentucky Transportation Cabinet (KYTC). Researchers performed a literature review, surveyed KYTC construction and design staff, engaged with Cabinet staff and industry members to understand the current state of practice, and evaluated quality- related attributes of the EED through case studies. The report presents a set of targeted recommendations for improving KYTC processes …

Dmd And Pod Modal Analysis For Store Separation, Nicholas Peters

Doctoral Dissertations and Master's Theses

Store separation from aircraft and spacecraft has historically been a critical and in some cases fatal issue for the aerospace industry. Given the severity of the issue much effort has been spent on the development of processes to identify failure flight conditions for store separation. The processes currently used for identifying potential failure conditions however are both resource intensive and iterative processes. A potential remedy to reducing resource use and improve turn around time in this process is the implementation of a mode based reduced order model (ROM) for modeling store separation. The objective of this study was to first …

Viscoplastic Study Of 3d Printed Carbon Fiber Composites, Alexander M. Seifans

Doctoral Dissertations and Master's Theses

The research presented here involves an attempt to model the viscoplastic response of 3D printed carbon fiber composites made using the Mark Two 3D printer by Markforged. The ability to manufacture composites through the use of 3D printers is relatively new and contains gaps in the various mechanical properties of the material, of interest is the viscoplastic response.

Due to the fabrication method, the properties of the composites cannot be assumed to be similar to that of conventionally made composites as the fused deposition in printing alters the material properties. In order to understand the effects of the printed fiber …

Antimicrobial Resistance Needs To Be Combated At Primary Levels Of Prevention By Nurses, Sarah Oerther, Daniel B. Oerther

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Post-Impact Flexural Behavior Of Carbon-Aramid/Epoxy Hybrid Composites, A. Wagih, T. A. Sebaey, A. Yudhanto, G. Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Hybrid polymeric composites are currently used in aerospace structures due to their specific strength and stiffness as well as larger design space. This paper presents an experimental study on residual flexural strength of impacted Carbon-aramid/Epoxy hybrid composite laminates. Specimens are designed in a sandwich form in which plies of aramid/epoxy represent the core and carbon/epoxy plies play the role of face sheets. This design is expected to take advantage of the high energy absorption capabilities of aramid/epoxy composites. We pre-damage such composites by performing low-velocity impact at different energy levels. Three-point bending tests then are used to measure the residual …