Engineering Commons^™

Antimicrobial Materials Via Thiol-Ene Chemistry, Dahlia Amato

Dissertations

With the increasing prevalence of antimicrobial resistance, the escalation of opportunistic/pathogenic infections is a looming global crisis. To avoid the pitfalls of conventional antibiotics, this dissertation focuses on developing macromolecular solutions to develop novel antimicrobial materials based on essential oils (thymol, carvacrol, and aldehydes). It is well established that essential oil derivatives exhibit high potency towards a wide range of pathogenic microbes. The rapid photopolymerization kinetics, limited by-products, and homogeneous network formation afforded by thiol-ene photopolymerization are utilized to either encapsulate essential oil derivatives or convert them into monomers which can subsequently be incorporated into new antimicrobial materials with new …

Polymer Nanocomposites Containing High Aspect Ratio Particulates: Innovation In Co-Extruded Multilayer Barrier Films, Kevin Meyers

Dissertations

Delaminated montmorillonite (MMT) clay/ maleic anhydride grafted LLDPE nanocomposite multilayer films with alternating layers of LDPE were produced through multilayer co-extrusion. The MMT concentration within the nanocomposite layers was increased through annealing the films in the melt due to a mismatch in interdiffusion rates of the polymer layers. Analysis of the nanocomposite layers upon annealing revealed that the platelets impinged upon one another resulting in significant improvement in oxygen barrier in the multilayer system, exceeding the results of bulk nanocomposites.

Model analysis demonstrated that increasing the nanoplatelet aspect ratio or initial concentration in the filled layers would lead to even …

An Underwater Vehicle Navigation System Using Acoustic And Inertial Sensors, Khalid M. Alzahrani

Doctoral Dissertations and Master's Theses

Unmanned Underwater Vehicles (UUVs) have become an essential tool for different underwater tasks. Compared with other unmanned systems, the navigation and localization for UUVs are particularly challenging due to the unavailability of Global Positioning System (GPS) signals underwater and the complexity of the unstable environment. Alternative methods such as acoustic positioning systems, Inertial Navigation Systems (INS), and the geophysical navigation approach are used for UUV navigation. Acoustic positioning systems utilize the characteristics of acoustic signals that have a lower absorption rate and a more extended propagation distance than electromagnetic signals underwater. The significant disadvantage of the INS is the “drift,” …

Numerical Simulation Of Shock Wave Propagation In Ducts With Grooves, Seyed Mehdi Mortazawy

Doctoral Dissertations and Master's Theses

The pressure attenuation of moving shocks when they propagate in ducts, is of great importance in a wide variety of applications, such as health, safety, and transportation. The objective of this research is to simulate the propagation of shock waves in ducts with roughness. The roughness is added in the form of grooves as in an existing experiment. Different shapes are considered in order to better understand the physics behind the evolution of the complex shock patterns resulting from diffraction, reflection and refraction of the primary moving shock. The contribution of grooves and duct shape on these phenomena and pressure …

Arm Position Measurement, Silvia Smith

Undergraduate Honors Capstone Projects

This capstone project addresses the design and implementation of a device that measures arm position and speed. The device is intended for use in conducting further research on the motion of limbs affected by cerebral palsy, and in the prototypic development of a device that could help control such motion, thereby allowing a user to accomplish daily tasks. This project includes the design of an appropriate experiment and testing apparatus to explore possible solution prototypes, along with suggested methods to perform analysis of the experiment results. This is considered to be the fundamental research necessary to better understand the scope …

Designing A Synthetic Spider Silk-Based Coating For Urinary Catheters To Reduce The Risk Of Cautis, Alexander Cook

Undergraduate Honors Capstone Projects

Urinary and Intravenous (IV) catheters are two of the most commonly used medical devices for administering vital drugs and obtaining diagnostic samples from patients. Unfortunately, hospital acquired infections (HAIs) occur at alarming rates due to catheter usage. The aim of this project was to design a urinary catheter that would decrease the occurrence of these infections with a catheter coating that utilizes the antimicrobial properties of synthetic spider silk in combination with the antiseptic chlorhexidine. This synthetic spider silk catheter will introduce a novel approach to catheterization in the medical industry.

Rickshaw For Common Ground, Marcus Dallin Cronin

Undergraduate Honors Capstone Projects

For this project my team and I were asked to design and manufacture a rickshaw, a device which will enable disabled individuals to experience outdoor hiking trails, for a non-profit organization based in Logan, Utah called Common Ground. Common Ground specializes in helping people with disabilities experience the outdoors in ways that would otherwise be impossible. The rickshaw will help Common Ground achieve its goals by providing them with a way to transport people with disabilities on moderately difficult hiking trails (i.e. Wind Caves Trail in Logan Canyon). In the past, Common Ground had use of a rickshaw that had …

Buffer Controlled Cache For Low Power Multicore Processors, Marven Calagos

Theses and Dissertations

This thesis proposes a buffered dual access mode cache to reduce power consumption in multicore caches for embedded systems. This cache is called Buffer Controlled Cache (BCC cache). The proposed scheme introduces a pre-cache buffer to determine how to access the cache. The proposed cache shows better prediction rates and lower power consumption than conventional caches, such as Phased cache and Way-prediction cache. For single core implementation, Simplescalar and Cacti simulators have been used for these simulations using SPEC2000 benchmark programs. The experimental results show that the proposed cache improves the power consumption by 37%-42% over the conventional caches. Multi2Sim …

Superharmonic Resonance Of Second Order For Electrostatically Actuated Mems Cantilevers, Martin Amador Botello

Theses and Dissertations

The nonlinear dynamics of electrostatically actuated micro-electro-mechanical system (MEMS) cantilever resonators are investigated. The applied Alternating Current (AC) voltage is in the realm of superharmonic resonance of the second order (near one-fourth of the natural frequency of the resonator) and hard excitations. Method of Multiple Scales (MMS) and Reduced Order Models (ROMs) are used to solve the dimensionless partial differential equation (PDE) of motion along with boundary and initial conditions. MMS transforms the PDE of motion into zero-order and first-order problems. ROMs uses mode shapes of vibration for undamped cantilever resonator as a basis of functions. ROM is …

Multifunctional Carbon Systems (Interlaminated Carbon Nanofiber Mats/ Carbon Nanotubes Polymer Composites), Homero Gonzalez Guardiola

Theses and Dissertations

Carbon nanomaterials have been an attractive topic within diverse industrial sectors given their outstanding properties for decades. One of the properties that has been calling attention is it’s shielding effectiveness (SE) for electromagnetic interference (EMI), because of the constant race of improving portable electronic and wireless communication devices among other applications. The present study, analyzes the properties of interlaminated Carbon Nanofiber (CNF) mats/Carbon Nanotubes (CNT) polymer composites, emphasizing in its capability to shield EMI. The CNF mats were developed with Polyvinyl alcohol (PVA) as a precursor and by means of the Forcespinning® technology which uses centrifugal force to create fibers …

Lead Doped Carbon Nanofibers In Li-Ion Batteries, Omar Torres

Theses and Dissertations

Lead acid batteries have been a very reliable rechargeable battery since its inception in the mid-1800s. Lithium-Ion batteries have been sought out for their light-weight and capacity of holding large amounts of energy in a small amount of space. Few studies have been conducted in the use of lead in lithium-ion batteries.

In this thesis, lead-doped carbon nanofibers were produced by using the Forcespinning® method and used as an anode on a lithium-ion battery. The morphology, material characterization and thermal properties of the anode material were analyzed using the Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Thermogravimetric Analysis …

Asynchronous Circuit Stacking For Simplified Power Management, Andrew Lloyd Suchanek

Graduate Theses and Dissertations

As digital integrated circuits (ICs) continue to increase in complexity, new challenges arise for designers. Complex ICs are often designed by incorporating multiple power domains therefore requiring multiple voltage converters to produce the corresponding supply voltages. These converters not only take substantial on-chip layout area and/or off-chip space, but also aggregate the power loss during the voltage conversions that must occur fast enough to maintain the necessary power supplies. This dissertation work presents an asynchronous Multi-Threshold NULL Convention Logic (MTNCL) “stacked” circuit architecture that alleviates this problem by reducing the number of voltage converters needed to supply the voltage the …

Self-Assembled Barium Titanate Nanoscale Films By Molecular Beam Epitaxy, Timothy Allen Morgan

Graduate Theses and Dissertations

One challenge of investigating ferroelectrics at the nanoscale has been controlling the stoichiometry during growth. Historically, the growth of barium titanate (BaTiO3) by molecular beam epitaxy has relied on a growth technique called shuttered RHEED. Shuttered RHEED controls the stoichiometry of barium titanate through the precise deposition of alternating layers of BaO and TiO2. While this approach has achieved 1% control of stoichiometry, finding self-limiting mechanisms to lock-in stoichiometry has been the focus of the growth community. The Goldschmidt tolerance factor predicts an unstable perovskite when barium sits in the titanium lattice site. The BaO-TiO2 phase diagram predicts a low-solubility …

Optimal Allocation Of Resources In Reliability Growth, Mohammadhossein Heydari

Graduate Theses and Dissertations

Reliability growth testing seeks to identify and remove failure modes in order to improve system reliability. This dissertation centers around the resource allocation across the components of a multi-component system to maximize system reliability. We summarize this dissertation’s contributions to optimal resource allocation in reliability growth.

Chapter 2 seeks to deploy limited testing resources across the components of a series-parallel system in effort to maximize system reliability under the assumption that each component’s reliability exhibits growth according to an AMSAA model with known parameters. An optimization model for this problem is developed and then extended to consider the allocation of …

Fibers For Skin Regeneration, Astrid Michelle Rodriguez Negron

Theses and Dissertations

This thesis presents the successful development of biocompatible Polyvinyl Butyral (PVB), PVB/Polylysine and PVB/Tannic Acid (TA)/Polylysine fibers from an ethanol solution, Polyhydroxybutyrate (PHB), PHB/Polylysine, PHB/TA/Polylysine fibers from a chloroform solution and Chitosan (CH)/Pullulan (PL)/TA and CH/PL/TA/Polylysine fibers from an aqueous solution. The fibers were mass produced utilizing the Forcespinning® (FS) technology. The morphology of the fibers was characterized using a scanning electron microscope (SEM) and the fibers average diameter was calculated. The thermal properties of the fibers were characterized using a thermogravimetric analyzer (TGA) and a differential scanning calorimeter (DSC). The antibacterial activity of the fibers was assessed using against …

The Effect Of Heat Generation In The Railroad Bearing Thermoplastic Elastomer Suspension Element On The Thermal Behavior Of Railroad Bearing Assembly, Oscar Osvaldo Rodriguez

Theses and Dissertations

Understanding the internal heat generation of the railroad bearing elastomer suspension element during operation is essential to predict its dynamic response and structural integrity, as well as to predict the thermal behavior of the complete railroad bearing assembly including the bearing adapter. The latter is essential for sensor selection and placement within the adapter (e.g., typical temperature sensors have operating ranges of up to 125°C or 257°F). The internal heat generation is a function of the loss modulus, strain, and frequency. Based on experimental studies, estimations of internally generated heat within the thermoplastic elastomer pad were obtained. The calculations show …

The Use Of Mixed Organic/Ionic Liquid Electrolytes With Forcespun Metal Oxides/Carbon Microfiber Electrodes In Lithium Ion Batteries, Jahaziel Villarreal

Theses and Dissertations

Conventional Lithium-Ion Battery (LIB) electrolytes have serious safety concerns because of highly flammability. In order to mitigate this drawback, alternative electrolytes with low volatility and non-flammable need to be synthesis. Ionic liquids (ILs) and mixed organic ionic liquid electrolytes (MOILEs) are the most suitable replacement for the highly flammable commercial organic electrolytes. In this academic investigation, a new perspective on the electrochemical performance of the ionic liquid EMI-TFSI as an alternate non-flammable electrolyte. In parallel, the use of Forcespun nanofibers as binder-free anodes will be analyzed to further improve overall electrochemical performance.

Service Quality Assessment For Cloud-Based Distributed Data Services, Arun Adiththan

Dissertations, Theses, and Capstone Projects

The issue of less-than-100% reliability and trust-worthiness of third-party controlled cloud components (e.g., IaaS and SaaS components from different vendors) may lead to laxity in the QoS guarantees offered by a service-support system S to various applications. An example of S is a replicated data service to handle customer queries with fault-tolerance and performance goals. QoS laxity (i.e., SLA violations) may be inadvertent: say, due to the inability of system designers to model the impact of sub-system behaviors onto a deliverable QoS. Sometimes, QoS laxity may even be intentional: say, to reap revenue-oriented benefits by cheating on resource allocations and/or …

Feasibility Of Harbor-Wide Barrier Systems: Preliminary Analysis For Boston Harbor, Paul Kirshen

Sustainable Solutions Lab

This report presents a preliminary feasibility assessment of harbor-wide barrier systems designed to protect Boston Harbor from coastal flooding caused by sea level rise (SLR) and storm surges. Conducted by the Sustainable Solutions Lab at the University of Massachusetts Boston and supported by the Boston Green Ribbon Commission, the study evaluates two primary configurations: an Outer Harbor Barrier (OHB) and an Inner Harbor Barrier (IHB). Using hydrodynamic modeling, economic cost-benefit analysis, and social vulnerability assessments, the study finds that while both barrier systems may reduce risk from extreme storm events, they do not mitigate regular tidal flooding without frequent gate …

Ph-Responsive Mercaptoundecanoic Acid Functionalized Gold Nanoparticles And Applications In Catalysis, Siyam M. Ansar, Saptarshi Chakraborty, Christopher L. Kitchens

Publications

Mercaptoundecanoic acid (MUA) functionalized gold nanoparticles (AuNP-MUA) were synthesized and demonstrated to possess pH-triggered aggregation and re-dispersion, as well as the capability of phase transfer between aqueous and organic phases in response to changes in pH. The pH of aggregation for AuNP-MUA is consistent with the pK_a of MUA (pH ~4) in solution, while AuNP-MUA phase transition between aqueous and organic phases occurs at pH ~9. The ion pair formation between the amine group in octadecylamine (ODA), the carboxylate group in MUA, and the hydrophobic alkyl chain of ODA facilitates the phase transfer of AuNP-MUA into an organic medium. …

Critical-Point Model Dielectric Function Analysis Of Wo3 Thin Films Deposited By Atomic Layer Deposition Techniques, Ufuk Kılıç, Derek Sekora, Alyssa Mock, Rafał Korlacki, Elena M. Echeverría, Natale J. Ianno, Eva Schubert, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

WO₃ thin films were grown by atomic layer deposition and spectroscopic ellipsometry data gathered in the photon energy range of 0.72-8.5 eV and from multiple samples was utilized to determine the frequency dependent complex-valued isotropic dielectric function for WO₃. We employ a critical-point model dielectric function analysis and determine a parameterized set of oscillators and compare the observed critical-point contributions with the vertical transition energy distribution found within the band structure of WO₃ calculated by density functional theory. We investigate surface roughness with atomic force microscopy and compare to ellipsometric determined effective roughness layer thickness.

From Digital Traces To Marketing Insights: Recovering Consumer Preferences For Digital Entertainment Services And Online Shopping, Ai Phuong Hoang

Dissertations and Theses Collection (Open Access)

IT innovations disrupt traditional business models and challenge conventional thinking. Thus, industry incumbents face fierce competition from start-ups with new business models and new ways of engaging customers. Digital entertainment goods and personalized services have become a lucrative market, which has undergone a transformation enabled by seamless Internet connections. Meanwhile, social networks and other online platforms have brought people and business even closer.

Entity Summarization Of Reviews And Micro-Reviews, Thanh Son Nguyen

Dissertations and Theses Collection (Open Access)

Along with the regular review content, there is a new type of user-generated content arising from the prevalence of mobile devices and social media, that is micro-review. Micro-reviews are bite-size reviews (usually under 200 char- acters), commonly posted on social media or check-in services, using a mobile device. They capture the immediate reaction of users, and they are rich in information, concise, and to the point. Both reviews and micro-reviews are useful for users to get to know the entity of interest, thus facilitating users in making their decision of purchasing or dining. However, the abundant number of both reviews …

Concomitant Crystallization In Propylene/Ethylene Random Copolymer With Strong Flow At Elevated Temperatures, Lirong Zheng, Lucia Fernandez-Ballester, Gerrit W. M. Peters, Zhe Ma

Department of Mechanical and Materials Engineering: Faculty Publications

Flow-induced crystallization of α- and γ-phases was studied for a propylene/ethylene random copolymer with 3.4 mol % ethylene at two high temperatures of 132 and 142 °C by combining a pressure-driven slit flow device with real-time synchrotron wide-angle X-ray diffraction. At 132 °C, it was found that both α- and γ-phases were generated at shear stresses ranging from 0.091 to 0.110 MPa and that the γ-phase always appeared later than the α-phase. However, for 142 °C and the same stresses, only the α-phase formed. Only upon cooling the partially crystallized copolymer did the γ-phase emerge. The lack of γ-crystals obtained …

Feasibility Study Of A Multi-Purpose Aircraft Concept With A Leading-Edge Cross-Flow Fan, Stanislav Karpuk

Doctoral Dissertations and Master's Theses

A wing-embedded Cross-Flow Fan (CFF) was first proposed as an active flow control (AFC) device nearly 40 years ago. The CFF can be employed as a propulsion device as well as a high-lift system. This thesis research focuses on investigating the use of CFF as a high-lift device for an Extremely Short Take-off and Landing (ESTOL) aircraft. The wing-embedded CFF performance analysis is mostly addressed from an aerodynamic perspective and focuses on using such AFC technology in the conceptual aircraft design process. In particular, the design trade study of an aircraft featuring CFF as a high-lift device applied to a …

2018 Spring Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for spring 2018. Includes photographs, upcoming events, recent publications, and student profiles.

Self-Assembly Of (111)-Oriented Tensile-Strained Quantum Dots By Molecular Beam Epitaxy, Christopher F. Schuck, Robin A. Mccown, Ashlie Hush, Austin Mello, Simon Roy, Joseph W. Spinuzzi, Paul J. Simmonds

Materials Science and Engineering Faculty Publications and Presentations

The authors report on a comprehensive study of the growth of coherently strained GaAs quantum dots (QDs) on (111) surfaces via the Stranski–Krastanov (SK) self-assembly mechanism. Recent reports indicate that the long-standing challenges, whereby the SK growth mechanism could not be used to synthesize QDs on (111) surfaces, or QDs under tensile strain, have been overcome. However, a systematic study of the SK growth of (111)-oriented, tensile-strained QDs (TSQDs) as a function of molecular beam epitaxy growth parameters is still needed. Here, the authors explore the effects of deposition amount, substrate temperature, growth rate, and V/III flux ratio on the …

Routine Million-Particle Simulations Of Epoxy Curing With Dissipative Particle Dynamics, Stephen Thomas, Monet Alberts, Michael M. Henry, Carla E. Estridge, Eric Jankowski

Materials Science and Engineering Faculty Publications and Presentations

Mesoscale simulation techniques have helped to bridge the length scales and time scales needed to predict the microstructures of cured epoxies, but gaps in computational cost and experimental relevance have limited their impact. In this work, we develop an open-source plugin epoxpy for HOOMD-Blue that enables epoxy crosslinking simulations of millions of particles to be routinely performed on a single modern graphics card. We demonstrate the first implementation of custom temperature-time curing profiles with dissipative particle dynamics and show that reaction kinetics depend sensitively on the stochastic bonding rates. We provide guidelines for modeling first-order reaction dynamics in a classic …

Sex Differences In Lower Limb Biomechanics During A Single-Leg Cut With Body Borne Load, Auralea Carylon Fain

Boise State University Theses and Dissertations

Introduction: Musculoskeletal injuries are ever-increasing in military personnel, particularly females. These musculoskeletal injuries are attributed to adaptations in lower limb biomechanics while performing routine military tasks, such as a single-leg cut, with the addition of body borne load. However, it is unknown if females and males exhibit similar lower limb biomechanics with the addition of body borne load during these tasks. This study sought to compare the lower limb biomechanical adaptations exhibited by females and males performing a single-leg cut with body borne load. Methods: Eleven females and 17 males had lower limb biomechanics quantified during a single-leg cut with …

Seasonality Of Tides In Southeast Asian Waters, Adam T. Devlin, Edward Zaron, David A. Jay, Stefan Talke

Civil and Environmental Engineering Faculty Publications and Presentations

An analysis of water level time series from 20 tide gauges in Southeast Asia finds that diurnal and semidiurnal astronomical tides exhibit strong seasonal variability of both amplitude and phase, which is not caused by known modulations of the astronomical tide-generating forces. Instead, it is found that the tidal properties are coherent with the western North Pacific monsoon index (WNPMI), indicating that monsoonal mechanisms are the likely cause. The study domain includes the Malacca Strait, Gulf of Thailand, the southern South China Sea, and Java Sea. The character of the geography and the tidal variability is different in each of …