Engineering Commons^™

Effect Of Fe2+/Fe3+Interconvertion On Reduction Behavior Of Fe3+ In Acidic Electrolytes, Jian-Xin Qin, Feng Lin, Wen-Ping Liu, Chao Chen, Meng-De Ren

Journal of Electrochemistry

The influences of ferrous/ferric (Fe²⁺/Fe³⁺) interconvertion on electrochemical reduction and electrode reaction of Fe³⁺ were investigated by using linear sweep voltammetry, potentiostatic method and cyclic voltammetry (CV) in acidic electrolytes containing chloride ion (Cl^-) and sulfate ion (SO₄^2-). It was shown that the reduction process of Fe³⁺/Fe²⁺ would take place in two independent stages: (1) the reduction of Fe³⁺ to Fe²⁺ at E=0.35V and (2) the co-precipitation of Fe²⁺ by forming Fe(OH)₂ (E≤-0.3 V) instead of Fe. The major effect of Fe^{2+ …}

Effect Of Calcium On Atmospheric Corrosion Resistance Of Bridge Steel, Dong-Liang Li, Gui-Qin Fu, Miao-Yong Zhu

Journal of Electrochemistry

The corrosion behavior of bridge steel in simulated hot and humid industrial-marine atmosphere was investigated by mass loss analysis, XRD, SEM, electrochemical methods and a wet/dry alternate immersion corrosion test using 0.1 mol•L^-1 NaCl+0.01 mol•L^-1 NaHSO₃ solutions. The corrosion depth (W) of experimental steels before and after calcium treatment versus time (t) curves showed a good agreement with the power function of W=Atⁿ. The corrosion products were mainly composed of amorphous phase and a small amount of crystals including α-FeOOH, β-FeOOH, γ-FeOOH and Fe₃O₄. Trace calcium could promote the formation of …

A Post-American World? Assessing The Cognitive And Attitudinal Impacts Of Challenges To American Exceptionalism, Jason A. Gilmore, Charles Rowling

Languages, Philosophy, and Communication Studies Faculty Publications

A number of voices have emerged in U.S. political discourse questioning the legitimacy of American exceptionalism, suggesting we are in a “post-American world.” Our research examines the effects that political messages that explicitly challenge American exceptionalism can have on U.S. public opinion. Drawing upon social identity theory, we find that explicit challenges to American exceptionalism significantly impact Americans’ views toward their own nation, their willingness to denigrate foreign publics, and their broader foreign policy preferences.

Exploring The Use Of A Time-Frequency Domain Technique For The Filtering Of Acoustic Emission/Microseismic Data, Charles Mborah, Maochen Ge, Zhigang Wang

Mining Engineering Faculty Research & Creative Works

The performance of acoustic emission/micro seismic (AE/MS) monitoring systems in mines is greatly impacted by background noise interference. Mine trucks/vehicles, fans, blasting and electrical spikes generate noise which negatively affect AE/MS signal quality. Using such datasets without filtering may lead to inaccurate determination of first arrivals and hence wrong source location. Also, data contaminated with noise makes manual identification and picking of the first arrivals impossible or difficult to achieve. This paper explored the use of stationary discrete wavelet transform as a filter to augment noise reduction on mine AE/MS data. The output of a test run on both noisy …

Microfluidic Pore Model Study On Physical And Geomechanical Factors Influencing Fluid Flow Behavior In Porous Media, Shuang Cao

LSU Doctoral Dissertations

Fluid flow in porous media is a subject of fundamental importance and relevant to numerous engineering applications. The comprehensive description of fluid interaction parameters containing wetting properties, fluid-fluid displacement ratio, and capillary pressure, are inevitably needed. Moreover, the fine-grained sediments’ response to various pore fluids and migration in porous media influences reservoir geomechanical properties and pore clogging is essential to a better understanding of fluids flow behavior.

This dissertation provides a detailed study of physical and geomechanical factors influencing fluids flow behavior in porous media. The two-dimensional micromodel tests have been conducted under a wide selection of fluids flow conditions. …

Luminescence Of Defects In The Structural Transformation Of Layered Tin Dichalcogenides, Peter Sutter, H.P. Komsa, A. V. Krasheninnikov, Y Huang, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Layered tin sulfide semiconductors are both of fundamental interest and attractive for energy conversion applications. Sn sulfides crystallize in several stable bulk phases with different Sn:S ratios (SnS2, Sn2, S3, and SnS), which can transform into phases with a lower sulfur concentration by introduction of sulfur vacancies (VS). How this complex behavior affects the optoelectronic properties remains largely unknown but is of key importance for understanding light-matter interactions in this family of layered materials. Here, we use the capability to induce VS and drive a transformation between few-layer SnS2 and SnS by electron beam irradiation, combined with in-situ cathodoluminescence spectroscopy …

Modifications To Commercial Printers To Enable Multi-Material Fabrication Of 3d Cellular Scaffolds, Lucas D. Albrecht

Theses - ALL

The scarcity of organs for patients that need transplants has led to exceedingly

lengthy waits for organ transplants for sick patients. Fabrication of tissues and organ

constructs in-vitro has potential to end the shortage, however many of the machines

used to create these tissues and organs are expensive, not easy to use, and do not

have any further practical applications. Bioprinting technology has the potential to

revolutionize the fabrication of biological constructs that can be used as in vitro model

tissues and vivo substitutes. Bioprinting is the process of using conventional 3D printing

methods and computer-aided-design (CAD) to create patient …

Cell Laden Hydrogel Microspheres Using 3d Printed Microfluidics, Sanika Nitin Suvarnapathaki

Theses - ALL

Cell laden hydrogel microspheres using 3D printed microfluidics

Abstract

By

Sanika Suvarnapathaki

Current tissue engineering therapies use macro-scale three dimensional (3D) scaffolds to treat tissue defects surgically. Uneven cell seeding and oxygen and media perfusion cause low cell viability in these macro-scale scaffolds. Microencapsulation, a technique of encapsulating cells in biocompatible polymers or hydrogels, has the potential to address these key issues, and therefore this technology has been used for numerous healthcare applications over the last two decades. Cell microencapsulation in hydrogels that mimic the tissue physiology and biochemistry has made it possible to use natural hydrogels like gelatin methacrylate …

Development And Evaluation Of A Connective Tissue Phantom Model For Subsurface Visualization Of Cancers Requiring Wide Local Excision, Kimberly S. Samkoe, Brent D. Bates, Niki N. Tselepidakis, Alisha V. Dsouza, Jason R. Gunn, Dipak B. Ramkumar, Keith D. Paulsen, Brian W. Pogue, Eric R. Henderson

Dartmouth Scholarship

Wide local excision (WLE) of tumors with negative margins remains a challenge because surgeons cannot directly visualize the mass. Fluorescence-guided surgery (FGS) may improve surgical accuracy; however, conventional methods with direct surface tumor visualization are not immediately applicable, and properties of tissues surrounding the cancer must be considered. We developed a phantom model for sarcoma resection with the near-infrared fluorophore IRDye 800CW and used it to iteratively define the properties of connective tissues that typically surround sarcoma tumors. We then tested the ability of a blinded surgeon to resect fluorescent tumor-simulating inclusions with ∼1-cm margins using predetermined target fluorescence intensities …

Detection, Diagnosis And Mitigation Of Malicious Javascript With Enriched Javascript Executions, Xunchao Hu

Dissertations - ALL

Malicious JavaScript has become an important attack vector for software exploitation attacks and imposes a severe threat to computer security. In particular, three major class of problems, malware detection, exploit diagnosis, and exploits mitigation, bring considerable challenges to security researchers. Although a lot of research efforts have been made to address these threats, they have fundamental limitations and thus cannot solve the problems.

Existing analysis techniques fall into two general categories: static analysis and dynamic analysis. Static analysis tends to produce inaccurate results (both false positive and false negative) and is vulnerable to a wide series of obfuscation techniques. Thus, …

Gas Phase Oxidation Of Levulinic Acid For The Production Of Maleic Anhydride Over Supported Vanadium Oxide Catalysts, Anargyros Chatzidimitriou

Dissertations - ALL

With continued depletion of fossil carbon, there is a need to utilize renewable sources of energy and consumer end products. In this context, we examine the aerobic oxidation of levulinic acid, a bio-based platform chemical derived from lignocellulosic biomass, to produce maleic anhydride, a valuable commodity chemical. This process is carried out over supported vanadium oxide catalysts. Yields as high as 71% of the theoretical maximum were achieved at 573 K over a vanadium oxide catalyst supported on SiO2. The exact mechanism underlying this transformation is complex, but our results suggest that maleic anhydride forms by the oxidative cleavage of …

Oxygen Transport Membrane Reactors For Oxy-Fuel Combustion And Carbon Capture Purposes, Ryan Falkenstein-Smith

Dissertations - ALL

This thesis investigates oxygen transport membrane reactors (OTMs) for the application of oxy-fuel combustion. This is done by evaluating the material properties and oxygen permeability of different OTM compositions subjected to a variety of operating conditions. The scope of this work consists of three components: (1) evaluate the oxygen permeation capabilities of perovskite-type materials for the application of oxy-fuel combustion; (2) determine the effects of dual-phase membrane compositions on the oxygen permeation performance and membrane characteristics; and (3) develop a new method for estimating the oxygen permeation performance of OTMs utilized for the application of oxy-fuel combustion.

SrSc0.1Co0.9O3-δ (SSC) is …

Investigating The Interaction Of A Supersonic Single Expansion Ramp Nozzle And Sonic Wall Jet, Matthew Berry

Dissertations - ALL

For nearly 80 years, the jet engine has set the pace for aviation technology around the world. Complexity of design has compounded upon each iteration of nozzle development, while the rate of fundamental fluids knowledge struggles to keep up. The increase in velocities associated with supersonic jets, have exacerbated the need for flow physics research. Supersonic flight remains the standard for military aircraft and is being rediscovered for commercial use. With the addition of multiple streams, complex nozzle geometries, and airframe integration in modern aircraft, the flow physics rapidly become more difficult. As performance capabilities increase, so do the noise …

Ensemble Methods For Anomaly Detection, Zhiruo Zhao

Dissertations - ALL

Anomaly detection has many applications in numerous areas such as intrusion detection, fraud detection, and medical diagnosis. Most current techniques are specialized for detecting one type of anomaly, and work well on specific domains and when the data satisfies specific assumptions.

We address this problem, proposing ensemble anomaly detection techniques that perform well in many applications, with four major contributions: using bootstrapping to better detect anomalies on multiple subsamples, sequential application of diverse detection

algorithms, a novel adaptive sampling and learning algorithm in which the anomalies are iteratively examined, and improving the random forest algorithms for detecting anomalies in streaming …

Design, Synthesis And Study Of Thermomechanically Active Polymer Networks Based On Latent Crosslinking Of Semicrystalline Polymers, Wenbin Kuang

Dissertations - ALL

Demand has arisen rapidly for smart materials in the world of the need to develop and understand new functional products like plastics, rubber, adhesives, fibers, and coatings. Such products are essentially composed of polymers, large molecules of high molecular weight with homogeneous or various repeating units, which researchers term “macromolecules” that engender specific structural, morphological, and physical and mechanical properties. Those polymers with the capacity to change their configuration in accordance with environmental alteration are specifically referred to as shape memory polymers (SMPs), attracting much interest of study both academically and industrially. Herein, this dissertation aims at design, fabrication, and …

Adsorption Of Iodine And Water On Silver-Exchanged Mordenite, Yue Nan

Dissertations - ALL

The reprocessing of used nuclear fuel to recover the fissile materials generates off gases including radioactive nuclides namely 3H (tritiated water, H3HO), 129I, 85Kr, 135Xe, and 14C. Due to its high quantity in off-gas streams and long half-life (1.59 million years), 129I removal from the off-gas streams is a significant objective of off-gas treatment.

129I retention by solid adsorbents was recognized a better strategy in comparison to liquid scrubbers due to the simplicity of system design and low cost. Among the studied adsorbents, reduced silver-exchanged mordenite (Ag0Z) was widely recognized as the state-of-art adsorbent for iodine removal. It has been …

Vortex Detection And Tracking In Massively Separated And Turbulent Flows, Yangzi Huang

Dissertations - ALL

The vortex produced at the leading edge of the wing, known as the leading edge vortex (LEV), plays an important role in enhancing or destroying aerodynamic force, especially lift, upon its formation or shedding during the flapping flight of birds and insects. In this thesis, we integrate multiple new and traditional vortex identification approaches to visualize and track the LEV dynamics during its shedding process. The study is carried out using a 2D simulation of a flat plate undergoing a 45 degree pitch-up maneuver. The Eulerian 𝛤1 function and 𝑄 criterion are used along with the Lagrangian coherent structures (LCS) …

Catalytic Synthesis Of Biodiesel Fuel Under Sub/Supercritical Conditions: Kinetics And Phase Behavior, Jiuxu Liu

Dissertations - ALL

In this thesis, transesterification of triglycerides and esterification of free fatty acids were executed under subcritical and supercritical alcohol conditions, and discussed in Chapter 2-5. The project was initiated by studying the phase behavior and kinetics of transesterification reactions under severe reaction conditions (T: 300-400 oC, P=200 bar), since those conditions were suggested and commonly used in the literature. At these conditions, triglycerides reacted with alcohol within minutes, and the oil-alcohol mixture formed a homogeneous phase which minimized the boundary mass transfer resistance. The composition change of the reaction mixture made the critical point of the system approach supercritical region …

Design Of Tribologically Enhanced Polymeric Materials For Biomedical Applications, Allen Osaheni

Dissertations - ALL

Anytime two surfaces are in normal contact, accompanied by tangential motion, there is potential for deterioration of one or both surfaces. Gradual wear, or the removal of surface material, is typically an undesirable event. Therefore, the need for lubrication arises to minimize the amount of shear stress that develops between opposing surfaces. This reduction in shear stress is characterized by the coefficient of friction (COF). Friction is one of the primary subjects of interest in tribology, the science of the friction and wear of articulating surfaces.

A number of fascinating tribological systems can be found in nature. One example which …

Rectangular Waveguide Filled With Uniaxial Medium And Negative Resistance Enhanced Composite Right/Left-Handed Transmission Line, Kepei Sun

Dissertations - ALL

Two wave-guiding problems are treated in this work. The first part addresses the problem of a rectangular waveguide filled with a uniaxially anisotropic or uniaxial medium. Different orientations of the optic axis of the uniaxial medium are considered and the wave transmission and modal behaviors are investigated. When the optic axis is aligned with one of the coordinate axes, i. e., x, y, or z axis, the method of wave decomposition with respect to the optic axis orientation is proposed and the complete analytic solutions are presented and compared with conventional transverse-to-z solutions. When the optic axis is tilted but …

A Life-Cycle Benefit/Cost Analysis Framework For Its Deployments, Xifan Chen

Dissertations - ALL

The primary objective of Transportation Systems Management and Operation (TSM&O) strategies, or Intelligent Transportation Systems (ITS) is to optimize the capacity of existing transportation infrastructure by reducing congestion. Over past decades, agencies and researchers investigated the use of various strategies such as deployment of adaptive traffic control systems (ATCS), ramp metering systems (RMS), surveillance through closed circuit TV (CCTV) cameras, and information sharing systems to achieve this objective. Life Cycle Agency Cost Agency Analysis (LCCA) of various alternative intelligent transportation strategies has received particular attention to identify the strategy with the lowest cost. However, increasing concerns over the impacts of …

Accelerated Construction Of Roadways: Life Cycle Assessment And Environmental Impacts, Sudipta Ghorai

Dissertations - ALL

Sustainability refers to a long-term perspective of economic, social, and environmental progress, which not only addresses the present conditions but also includes the needs of future generations. The massive network of roadways in United States has the potential to contribute considerably towards achieving sustainability in the infrastructure sector. The “triple bottom line” of sustainability, if incorporated in roadway development projects, can address issues like climate change, environmental protection, funds optimization, and social equity. This study focuses on the life cycle assessment (LCA) of arterial improvement projects. Preservation treatments help in extending the remaining service life of roads; but at the …

Online Learning With Bandits For Coverage, Mahmuda Rahman

Dissertations - ALL

With the rapid growth in velocity and volume, streaming data compels decision support systems to predict a small number of unique data points in due time that can represent a massive amount of correlated data without much loss of precision. In this work, we formulate this problem as the {\it online set coverage problem} and propose its solution for recommendation systems and the patrol assignment problem.

We propose a novel online reinforcement learning algorithm inspired by the Multi-Armed Bandit problem to solve the online recommendation system problem. We introduce a graph-based mechanism to improve the user coverage by recommended items …

Semi-Open Space And Micro-Environmental Control For Improving Thermal Comfort, Indoor Air Quality, And Building Energy Efficiency, Meng Kong

Dissertations - ALL

Local air delivery, heating, and cooling combined with local space partition and confinement (called semi-open space or SOS) have the potential to provide micro-environment that is tailored to the individual preference of the occupants, and hence increase the percentage of satisfied occupancy from currently 80% to near 100%. This research investigates the use of a micro-environmental control system (µX) and semi-open space (SOS) to efficiently provide the desired thermal comfort and air quality conditions for individual occupants while the ambient air temperature set-points were relaxed for reducing the overall energy consumption of the building. A computational fluid dynamics (CFD) model …

Associative Pattern Recognition For Biological Regulation Data, Yiou Xiao

Dissertations - ALL

In the last decade, bioinformatics data has been accumulated at an unprecedented rate, thanks to the advancement in sequencing technologies. Such rapid development poses both challenges and promising research topics. In this dissertation, we propose a series of associative pattern recognition algorithms in biological regulation studies. In particular, we emphasize efficiently recognizing associative patterns between genes, transcription factors, histone modifications and functional labels using heterogeneous data sources (numeric, sequences, time series data and textual labels).

In protein-DNA associative pattern recognition, we introduce an efficient algorithm for affinity test by searching for over-represented DNA sequences using a hash function and modulo …

Ahoy Aggies! | College Of Engineering, Usu College Of Engineering

College of Engineering News

In landlocked Utah, freshmen engineering students at Utah State University got a hands-on lesson in sailing the open seas.

Silver Photodiffusion Into Ge-Rich Amorphous Germanium Sulfide—Neutron Reflectivity Study, Y. Sakaguchi, H. Asaoka, M. Mitkova

Electrical and Computer Engineering Faculty Publications and Presentations

Silver diffuses into chalcogenide films upon light exposure, and the kinetics of photodiffusion has been a subject of various investigations because of the difficulties in the in situ determination of the time-dependent Ag reaction and diffusion development in the chalcogenide layers. In this paper, we report the results of time-resolved neutron reflectivity measurement of Ag/Ge₄₀S₆₀/Si substrates under light exposure to clarify the kinetics of Ag photodiffusion into Ge-rich Ge chalcogenides. It reveals that Ag ions diffuse all over the Ge chalcogenide host layer once Ag dissolves into the layer without forming a metastable reaction layer unlike …

Inorganic Biodegradable Substrates For Devices And Systems, Chang-Soo Kim, Richard K. Brow, D. E. Day

Electrical and Computer Engineering Faculty Research & Creative Works

Disclosed are biodegradable glass substrates that are useful as functional elements of solid-state devices. In particular, biodegradable glass substrates having a rapidly degradable glass and a slowly degradable glass provide a structural platform that completely dissolves following a desired operational lifetime of devices such as implanted electronic devices, implanted sensor devices, and optical fibers.

Microstructure And Mechanical Properties Of Additive Manufacturing Titanium Alloys After Thermal Processing, Ahmet Alptug Tanrikulu

Dissertations and Theses

Titanium alloys are widely used for aerospace and biomaterial applications since their high specific strength, and high corrosion resistivity. Besides these properties, titanium is an excellent biocompatible material widely used for internal body implants. Because the products have complex geometries in both applications, Additive Manufacturing (AM) methods have been recently applied for production. AM methods can process a direct 3-D shape of the final product, decrease total production time and cost. However, high residual stress of the final product limits the application of AM components, especially the ones that are exposed to cyclic loading. In the present study, the initial …

Agenda For The Fifth Meeting Of The Forum On Soil Dynamics, Shamsher Prakash

Forum for Promotion of Soil Dynamics in India

No abstract provided.