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Full-Text Articles in Engineering

Volume Frequency Response Method For Determining Mass Transfer Mechanisms Of O2 In Carbon Molecular Sieve 3k172, Olivia Smithson Oct 2020

Volume Frequency Response Method For Determining Mass Transfer Mechanisms Of O2 In Carbon Molecular Sieve 3k172, Olivia Smithson

Theses and Dissertations

Carbon molecular sieves (CMS) have grown more desirable over the years as an adsorbent for industrial separation processes as CMS technology has advanced. CMS is commonly used in nitrogen inerting (i.e, oxygen removal from air), carbon dioxide removal from methane and oxygen purification. However, knowledge of the dynamic behavior of these gases on CMS is needed to design and operate efficient and effective separation processes. For this reason, the mass transfer resistances within the micropore at both low and high frequencies were characterized using frequency response, COMSOL Multiphysics modeling, and MATLAB optimization , because frequency response methods have demonstrated the …


Introduction To Special Issue Of Irrigation Science: Improving Irrigation Management Across The Ogallala Aquifer, Usa, Allan A. Andales, Daran Rudnick, José L. Chávez Oct 2020

Introduction To Special Issue Of Irrigation Science: Improving Irrigation Management Across The Ogallala Aquifer, Usa, Allan A. Andales, Daran Rudnick, José L. Chávez

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Groundwater stored in aquifers is a major source of irrigation water for many agricultural regions that receive insufficient precipitation for crop production. In the U.S.A., the High Plains aquifer (HPA) that underlies parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming supplies irrigation water for agricultural production. The HPA underlies around 450,658 km2 (174,000 mi2) of which the Ogallala aquifer is the principal geologic formation underlying 347,059 km2 (134,000 mi2) (Gutentag et al. 1984). The Ogallala aquifer is primarily a water table (unconfined) aquifer with saturated thickness ranging from 0 …


Anomalous Growth Of Al8Mo3 Phase During Interdiffusion And Reaction Between Al And Mo, Abhishek Mehta, Le Zhou, Dennis D. Keiser Jr., Yongho Sohn Oct 2020

Anomalous Growth Of Al8Mo3 Phase During Interdiffusion And Reaction Between Al And Mo, Abhishek Mehta, Le Zhou, Dennis D. Keiser Jr., Yongho Sohn

Mechanical Engineering Faculty Research and Publications

No abstract provided.


Development Of A Grass Measurement Optimisation Tool To Efficiently Measure Herbage Mass On Grazed Pastures, D. J. Murphy, B. O'Brien, Michael D. Murphy Oct 2020

Development Of A Grass Measurement Optimisation Tool To Efficiently Measure Herbage Mass On Grazed Pastures, D. J. Murphy, B. O'Brien, Michael D. Murphy

Publications

Accurate and efficient estimation of herbage mass is essential for optimising grass utilisation and increasing profit for pasture farming. There is no definitive sampling protocol for grass measurement on Irish pastures. This paper presents the Grass Measurement Optimisation Tool (GMOT), designed to generate measurement protocols that optimise for time and accuracy. The GMOT was designed in the form of a decision support tool that generates interactive paddock maps that guide the farmer on how to optimally measure their pastures in a random stratified manner based on GPS co-ordinates, resulting in accurate non-biased estimations of mean herbage mass. Rising plate meter …


Detection And Estimation Of Inundation And Associated Risks Using Traffic And Monitoring Cameras And Image Processing Under Extreme Flooding Conditions, Suyun Ham Ph.D, Seongjin Noh Ph.D, Dong-Jun Seo Ph.D, Yin Chao Yu, Sangoo Kang Oct 2020

Detection And Estimation Of Inundation And Associated Risks Using Traffic And Monitoring Cameras And Image Processing Under Extreme Flooding Conditions, Suyun Ham Ph.D, Seongjin Noh Ph.D, Dong-Jun Seo Ph.D, Yin Chao Yu, Sangoo Kang

Publications

The main objective of this project is to develop an inundation detection and evaluation framework using images from traffic monitoring cameras and reliable flood monitoring under extreme precipitation conditions. This study presents a comparative assessment of image enhancement and segmentation techniques to automatically identify the flash flooding from the low-resolution images taken by traffic-monitoring cameras. Due to inaccurate equipment in severe weather conditions (e.g., raindrops or light refraction on camera lenses), low-resolution images are subject to noises that degrade the quality of information. De-noising procedures are carried out for the enhancement of images by removing different types of noises. After …


Real-Time Early Detection And Monitoring Of Flooding Using Low-Cost Highly Sensitive Ultrasound Sensing Of Water Level, Suyun Ham Ph.D, Seongjin Noh Ph.D, Dong-Jun Seo Ph.D, Sanggoo Kang, Dafnik Saril Kumar David Oct 2020

Real-Time Early Detection And Monitoring Of Flooding Using Low-Cost Highly Sensitive Ultrasound Sensing Of Water Level, Suyun Ham Ph.D, Seongjin Noh Ph.D, Dong-Jun Seo Ph.D, Sanggoo Kang, Dafnik Saril Kumar David

Publications

Flooding poses safety hazards to motorists, emergency and maintenance crews and may cause costly damage to transportation infrastructure and its operation. Flash flooding, in particular, causes the most flood-related deaths According to NOAA, in 2017 alone, flash flooding also caused $60.7 billion worth of economic damage. Low-water crossings are among the first places where deaths and significant damages to vehicles occur during flooding. With flash flooding, when a critical corridor is blocked by a high level of water, it affects the safety of the general public. To keep the critical corridors open as long as possible, and to minimize losses …


Abq Streets: Creating Alternative Residential Street Designs, Gregory Rowangould Ph.D, Nick N. Ferenchak Ph.D Oct 2020

Abq Streets: Creating Alternative Residential Street Designs, Gregory Rowangould Ph.D, Nick N. Ferenchak Ph.D

Publications

This research evaluates opportunities for retrofitting residential streets with alterative designs with the overall goal of improving their function, reducing their negative impacts and reducing maintenance costs. This is accomplished through three main research tasks. First, we conduct a comprehensive review of the street design literature with a focus on studies that report how alterative or unique designs that are relevant to the residential street context affect travel behavior, traffic flow, safety, crime and environmental impacts. We then survey residential streets in several study neighborhoods to measure typical design features and cross sections. With this information we then evaluate which …


Real-Time Work Zone Traffic Management Via Unmanned Air Vehicles, Charles Malveaux Ph.D, Marcio De Queiroz Ph.D, Xin Li Ph.D, Hany Hassan Ph.D, Zewei He Ph.D Oct 2020

Real-Time Work Zone Traffic Management Via Unmanned Air Vehicles, Charles Malveaux Ph.D, Marcio De Queiroz Ph.D, Xin Li Ph.D, Hany Hassan Ph.D, Zewei He Ph.D

Publications

Highway work zones are prone to traffic accidents when congestion and queues develop. Vehicle queues expand at a rate of 1 mile every 2 minutes. Back-of-queue, rear-end crashes are the most common work zone crash, endangering the safety of motorists, passengers, and construction workers. The dynamic nature of queuing in the proximity of highway work zones necessitates traffic management solutions that can monitor and intervene in real time. Fortunately, recent progress in sensor technology, embedded systems, and wireless communication coupled to lower costs are now enabling the development of real-time, automated, “intelligent” traffic management systems that address this problem. The …


Assessment Of Compatibility Of Mineral Aggregates And Binders Used In Highway Construction And Maintenance Projects, Zahid Hossain Ph.D, Ashraf Elsayed Ph.D, Tandra Bagchi, Sumon Roy Oct 2020

Assessment Of Compatibility Of Mineral Aggregates And Binders Used In Highway Construction And Maintenance Projects, Zahid Hossain Ph.D, Ashraf Elsayed Ph.D, Tandra Bagchi, Sumon Roy

Publications

Stripping and delamination have been deemed as some of the major premature pavement distresses to most state Departments of Transportations (DOTs) and highway agencies including the Arkansas Department of Transportation (ARDOT). It is believed that the poor compatibility between asphalt binders and aggregates is one of the major reasons behind this. This study aims to analyze the compatibility of selected asphalt binders and aggregates used in Arkansas. Asphalt binders used in this study include PG 64-22, PG 70-22, and PG 76-22; each prepared from two different crude courses. Additionally, four different types of aggregates (sandstone, limestone, gravel, and dolomite) from …


Impact Of Arsenic Species On Self-Assembly Of Triangular And Hexagonal Tensile-Strained Gaas(111)A Quantum Dots, Christopher F. Schuck, Kevin D. Vallejo, Trent Garrett, Qing Yuan, Ying Wang, Baolai Liang, Paul J. Simmonds Oct 2020

Impact Of Arsenic Species On Self-Assembly Of Triangular And Hexagonal Tensile-Strained Gaas(111)A Quantum Dots, Christopher F. Schuck, Kevin D. Vallejo, Trent Garrett, Qing Yuan, Ying Wang, Baolai Liang, Paul J. Simmonds

Materials Science and Engineering Faculty Publications and Presentations

We use dimeric arsenic (As2) or tetrameric arsenic (As4) during molecular beam epitaxy to manipulate the structural and optical properties of GaAs(111)A tensile-strained quantum dots (TSQDs). Choice of arsenic species affects nucleation and growth behavior during TSQD self-assembly. Previously, epitaxial GaAs(111)A TSQDs have been grown with As4, producing TSQDs with a triangular base, and 'A-step' edges perpendicular to the three 1̅1̅2 directions. We demonstrate that using As2 at low substrate temperature also results in triangular GaAs(111)A TSQDs, but with 'B-step' edges perpendicular to the three 112̅ directions. We can therefore invert the crystallographic …


A Review Of Inkjet Printed Graphene And Carbon Nanotubes Based Gas Sensors, Twinkle Pandhi, Ashita Chandnani, Harish Subbaraman, David Estrada Oct 2020

A Review Of Inkjet Printed Graphene And Carbon Nanotubes Based Gas Sensors, Twinkle Pandhi, Ashita Chandnani, Harish Subbaraman, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

Graphene and carbon nanotube (CNT)-based gas/vapor sensors have gained much traction for numerous applications over the last decade due to their excellent sensing performance at ambient conditions. Inkjet printing various forms of graphene (reduced graphene oxide or modified graphene) and CNT (single-wall nanotubes (SWNTs) or multiwall nanotubes (MWNTs)) nanomaterials allows fabrication onto flexible substrates which enable gas sensing applications in flexible electronics. This review focuses on their recent developments and provides an overview of the state-of-the-art in inkjet printing of graphene and CNT based sensors targeting gases, such as NO2, Cl2, CO2, NH3 …


Deep Reinforcement Learning Approach To Solve Dynamic Vehicle Routing Problem With Stochastic Customers, Waldy Joe, Hoong Chuin Lau Oct 2020

Deep Reinforcement Learning Approach To Solve Dynamic Vehicle Routing Problem With Stochastic Customers, Waldy Joe, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

In real-world urban logistics operations, changes to the routes and tasks occur in response to dynamic events. To ensure customers’ demands are met, planners need to make these changes quickly (sometimes instantaneously). This paper proposes the formulation of a dynamic vehicle routing problem with time windows and both known and stochastic customers as a route-based Markov Decision Process. We propose a solution approach that combines Deep Reinforcement Learning (specifically neural networks-based TemporalDifference learning with experience replay) to approximate the value function and a routing heuristic based on Simulated Annealing, called DRLSA. Our approach enables optimized re-routing decision to be generated …


Selecting The Most Feasible Construction Phasing Plans For Urban Highway Rehabilitation Projects, Kunhee Choi Ph.D, H. David Jeong Ph.D, Yong-Cheol Lee, Yangtian Yin Oct 2020

Selecting The Most Feasible Construction Phasing Plans For Urban Highway Rehabilitation Projects, Kunhee Choi Ph.D, H. David Jeong Ph.D, Yong-Cheol Lee, Yangtian Yin

Publications

Despite the abundance of research that has aimed to understand the effects of highway work zones, very little definitive information is available concerning the determination of work zone length (WZL). Quantitative studies that holistically model WZL are very rare. To fill this gap, this study identifies critical factors affecting WZL and develops decision support models that determine the optimal WZL in a balanced tradeoff between motorists’ inconvenience due to traffic disruption and their opportunity cost. A high-confidence dataset was created by conducting a series of scheduling and traffic simulations and analyses. The results revealed that traffic loading and work zone …


Seismic Ground Motion Data Analyses For North-East Arkansas, Zahid Hossain Ph.D, Ashraf Elsayed Ph.D, Md Ariful Hasan, Md Rafiue Islam Oct 2020

Seismic Ground Motion Data Analyses For North-East Arkansas, Zahid Hossain Ph.D, Ashraf Elsayed Ph.D, Md Ariful Hasan, Md Rafiue Islam

Publications

Estimation of liquefaction resistance and shear velocities are key elements in the assessment of potential earthquake damage of existing and new construction sites. The Arkansas Department of Transportation (ARDOT) and other agencies in the region need ground motion response analysis (GMRA) data of specific construction sites. As part of a recent ARDOT’s Transportation Research Committee (TRC) project, researchers have conducted geophysical investigations several construction sites in northeast Arkansas over the past twelve years. The current study gathered the previously reported test data and estimated seismic hazard properties such as shear wave velocity profiles and seismic hazard coefficients for nearby locations. …


Enhancing Evaluation Of Wildlife Detection Systems, Nick N. Ferenchak Ph.D Oct 2020

Enhancing Evaluation Of Wildlife Detection Systems, Nick N. Ferenchak Ph.D

Publications

Every year in the United States, wildlife-vehicle collisions (WVCs) cause 200 human fatalities, 26,000 human injuries, and substantial harm to wildlife populations, resulting in approximately $8.4 billion in total costs. The research team examined two US 64 bridges located near Lumberton, New Mexico that were designed to allow wildlife to cross underneath. Monitoring stations were positioned at each of the crossings so that both wildlife approaches and passages were observed. Special mounting brackets were designed and fabricated to allow for the installation of monitoring equipment. Wildlife observations were supplemented with WVC counts. Over seven months of study, nearly 100,000 wildlife …


Optimizing The Geometric Configuration And Manufacturing Process Of High Mast Illumination Poles, Arturo Montoya Ph.D, Adolfo Matamoros Ph.D, Reza Nasouri, Echizeni Ikpah, Arsalan Majlesi Oct 2020

Optimizing The Geometric Configuration And Manufacturing Process Of High Mast Illumination Poles, Arturo Montoya Ph.D, Adolfo Matamoros Ph.D, Reza Nasouri, Echizeni Ikpah, Arsalan Majlesi

Publications

This work presents the development of a high-fidelity model that accounts for the cumulative effect of welding and hot- dip galvanizing on the determining the resulting residual stresses and deformations induced during the manufacturing process of high mast illumination poles (HMIPs). This model is meant to elucidate the root causes of weld toe cracks in HMIPs. A TxDOT pole-to-base plate connection detail was used as the reference model in the analysis. Welding was modeled using the plug-in Abaqus Welding Interface (AWI), which automatically implements a series of sequential thermal and mechanical analyses. Then, the welding stress results were used as …


Bridge Construction Monitoring Using Lidar For Quantified, Objective Quality-Control Quality-Assurance (Qoqcqa), Fernando Moreu Ph.D, Chris Lippitt Ph.D, Xinxing Yuan Oct 2020

Bridge Construction Monitoring Using Lidar For Quantified, Objective Quality-Control Quality-Assurance (Qoqcqa), Fernando Moreu Ph.D, Chris Lippitt Ph.D, Xinxing Yuan

Publications

Transportation infrastructure construction quality control and quality assurance demands construction monitoring by field inspectors. Currently, these inspectors monitor infrastructure by measuring and photographing structures. These tasks allow them to assess any correction decision during construction or to inform about the quality of the construction process for the future. In order to promote and objective decisions obtained during infrastructure construction, the proposed research project developed and implemented a methodology to measure construction progress and compared it with the designed 3D shape, quantifying the difference. This proposed project includes implementation for the development of DOT standards that could be added in near …


The Impacts Of Increased Adverse Weather Events On Freight Movement, Kyung "Kate" Hyun Ph.D, Stephen P. Mattingly Ph.D, Mehrdad Arabi Oct 2020

The Impacts Of Increased Adverse Weather Events On Freight Movement, Kyung "Kate" Hyun Ph.D, Stephen P. Mattingly Ph.D, Mehrdad Arabi

Publications

Freight transportation is a major economic backbone of the United States and is vital to sustaining the nation’s economic growth. Ports, as one of the primary components of freight transportation and important means of integrating into the global economic system, have experienced significant growth and increased capacity during the past two decades. The study addresses an important national freight mobility goal to enhance the resilience of the port transportation operations in the event of extreme weather events. This study develops an adaptable resilience assessment framework that evaluates the impact of a disruptive event on transportation operations. The framework identifies dynamic …


Development Of Corrosion Inhibiting Geopolymers Based Cement For Transportation Infrastructure, Homero Castaneda, Miladin Radovic, Changkyu Kim, Oscar Huang Oct 2020

Development Of Corrosion Inhibiting Geopolymers Based Cement For Transportation Infrastructure, Homero Castaneda, Miladin Radovic, Changkyu Kim, Oscar Huang

Publications

Geopolymers are gaining attention as affordable, sustainable, and eco-friendly replacement for Ordinary Portland Cement (OPC) in concrete civil structures. More importantly, Geopolymer-based Cement (GPC) provide sustainable and environmentally friendly alternative to OPCs as GPC can be processed at room temperatures from aqueous solutions of waste materials (e.g., fly ash) or abounded natural sources (e.g., clay) and thus reduce significant CO2 production associated with processing of OPC. Although, a lot of work has been done on improving mechanical properties of GPC over the last two decades, there are only a few studies on effects of GPC concrete on steel rebar …


Eco-Friendly Stabilization Of Sulfate-Rich Expansive Soils Using Geopolymers For Transportation Infrastructure, Xinbao Yu, Anand Puppala, Miladin Radovic, Sayantan Chakraborty, Jungyeon Jang, Oscar Huang Oct 2020

Eco-Friendly Stabilization Of Sulfate-Rich Expansive Soils Using Geopolymers For Transportation Infrastructure, Xinbao Yu, Anand Puppala, Miladin Radovic, Sayantan Chakraborty, Jungyeon Jang, Oscar Huang

Publications

Traditional calcium-based stabilizers, such as lime, to stabilize sulfate-rich expansive soils, are lasting-challenges in geotechnical engineering. The biggest problem with using calcium-based stabilizers is that when calcium and water are exposed to sulfate-rich expansive soils, they form ettringite as an expansive mineral, which causes sulfate-induced heaving. The study aimed to investigate the feasibility of stabilizing sulfate-rich expansive soils using geopolymers for transportation infrastructure. Literature review on sulfate-induced heaving and sulfate-rich soils stabilized with geopolymers suggests a direction for how to stabilize sulfate soils using geopolymers. The engineering tests were conducted to determine the swell, shrinkage, and strength behavior of natural, …


Advanced Modeling And Design Methodology For Pavements Using Plasticity-Based Shakedown Theory, Shengli Chen, Chao Sun, Xu Wang, Zhiming Zhang Oct 2020

Advanced Modeling And Design Methodology For Pavements Using Plasticity-Based Shakedown Theory, Shengli Chen, Chao Sun, Xu Wang, Zhiming Zhang

Publications

Pavement design is a process intended to find the most economical combination of layer thickness and material type for the pavement, taking into account the properties of the subgrade soil and the traffic to be carried during the service life of the road. The currently prevalent methods of pavement analysis and design, however, are more or less empirical in U.S., which possess the shortcoming that the important type of pavement distress of rutting related to the accumulation of plastic or permanent deformations cannot be effectively considered. This project proposes an exploratory study on the application of the plasticity theory-based shakedown …


Partially Reprapable Automated Open Source Bag Valve Mask-Based Ventilator, Aliaksei Petsiuk, Nagendra G. Tanikella, Samantha Dertinger, Adam Pringle, Shane Oberloier, Joshua M. Pearce Oct 2020

Partially Reprapable Automated Open Source Bag Valve Mask-Based Ventilator, Aliaksei Petsiuk, Nagendra G. Tanikella, Samantha Dertinger, Adam Pringle, Shane Oberloier, Joshua M. Pearce

Michigan Tech Publications, Part 1

This study describes the development of a simple and easy-to-build portable automated bag valve mask (BVM) compression system, which, during acute shortages and supply chain disruptions can serve as a temporary emergency ventilator. The resuscitation system is based on the Arduino controller with a real-time operating system installed on a largely RepRap 3-D printable parametric component-based structure. The cost of the materials for the system is under $170, which makes it affordable for replication by makers around the world. The device provides a controlled breathing mode with tidal volumes from 100 to 800 mL, breathing rates from 5 to 40 …


Association Of Liver Tissue Optical Properties And Thermal Damage, Vivek K. Nagarajan, Jerrold M. Ward, Bing Yu Oct 2020

Association Of Liver Tissue Optical Properties And Thermal Damage, Vivek K. Nagarajan, Jerrold M. Ward, Bing Yu

Biomedical Engineering Faculty Research and Publications

Background and Objectives

Complete thermocoagulation of tumors is vital to minimize the risk of local tumor recurrence after a thermal ablation. Histological assessments are not real-time and require experienced pathologists to grade the thermal damage (histopathology) [Correction added on 21 January, 2020 after first online publication: After thermal damage in the preceding sentence, (histopathology) was added]. Real-time assessment of thermal tissue damage during an ablation is necessary to achieve optimal tumor ablation. In our previous studies, we found that continuous monitoring of the wavelength-averaged (435–630 nm) tissue absorption coefficient (µa) and the reduced scattering coefficient () during …


Methods For Dynamic Stabilization, Performance Improvement, And Load Power Sharing In Dc Power Distribution Systems, Hessamaldin Abdollahi Oct 2020

Methods For Dynamic Stabilization, Performance Improvement, And Load Power Sharing In Dc Power Distribution Systems, Hessamaldin Abdollahi

Theses and Dissertations

Modern DC power distribution systems (DC-PDS) offer high efficiency and flexibility which make them ideal for mission-critical applications such as on-board power systems of All-Electric ships, electric vehicles, More-Electric-Aircrafts, and DC Microgrids. Despite these attractive features, there are still challenges that need to be addressed. The two most important challenges are system stability and load power sharing. The stability and performance are of concern because DC-PDS are typically formed by the interconnection of several feedback-controlled power converters. The resulting interactions can lead to destabilizing dynamics. Likewise, in a DC-PDS there are several source converters that are operating in parallel to …


Computational Modeling Of Radiation Damage In A Multi-Phase Ceramic Waste Form Using Moose, Zeyu Chen Oct 2020

Computational Modeling Of Radiation Damage In A Multi-Phase Ceramic Waste Form Using Moose, Zeyu Chen

Theses and Dissertations

Ceramic waste forms have been proposed to replace the traditional glassy waste forms for long term stabilization of radionuclides. These waste forms are constantly exposed to self-irradiation emitted from the constituent radionuclides causing their material properties to change accordingly. It has been known that the radiation damage in waste forms is dominated by alpha particles emitted from transuranic (TRU) radionuclides. Since alpha particles usually have a range of 10~20 μm in such waste forms, some fraction of any non-transuranic containing phases (for a multiphase waste form) will be undamaged (or less damaged) if containing large enough grain sizes. Modeling and …


Use Of Geospatial Technique To Estimate Traffic Volume On South Carolina Roads, Ryan Andrew Devine Oct 2020

Use Of Geospatial Technique To Estimate Traffic Volume On South Carolina Roads, Ryan Andrew Devine

Theses and Dissertations

Data from the Federal Highway Administration (FHWA) indicates that there is an increase in the number of vehicles on already congested roadways. For a department of transportation (DOT) to keep up with this increased demand, it is necessary for them to continuously collect and monitor traffic volume on the roads they maintain. One of the most important parameters that DOTs collect and use for traffic engineering and transportation planning studies is annual average daily traffic (AADT). The DOTs are also required to collect and report AADTs to the Federal Highway Administration annually as part of the Highway Performance Monitoring System …


Hydrogenation Of Dimethyl Oxalate To Ethylene Glycol Over Silica Supported Copper Catalysts, Xinbin Yu Oct 2020

Hydrogenation Of Dimethyl Oxalate To Ethylene Glycol Over Silica Supported Copper Catalysts, Xinbin Yu

Theses and Dissertations

Ethylene glycol is a bulk chemical and hydrogenation of dimethyl oxalate (DMO) on Cu/SiO2 catalysts is the final reaction step in a growing industrial syngas to ethylene glycol (StEG) process. Efforts to improve the performance of the catalysts are still ongoing and the detailed catalytic mechanism remains controversial.

In the present work, a series of 10 wt% Cu/SiO2 is prepared.by urea hydrolysis method and indium species is introduced by incipient wetness impregnation. Reaction studies show that 0.25 wt%-0.5 wt% of indium species can dramatically enhance the performance of 10 wt% Cu/SiO2 catalyst. Various characterizations reveal that indium species …


Evaluating The Stabilization Of Gypseous And Gypsiferous Sands Using Different Chemical Additives To Mitigate Gypsum Dissolution, Mohammed Kamil Faris Oct 2020

Evaluating The Stabilization Of Gypseous And Gypsiferous Sands Using Different Chemical Additives To Mitigate Gypsum Dissolution, Mohammed Kamil Faris

Theses and Dissertations

Gypsum, which is dihydrate calcium sulfate, (CaSO4.2H2O), is widely available in different sizes, from the size of a rock to the size of a few micrometers as a mineral, in different types of soils. It is primarily found mainly in arid and semi-arid areas around the world at different depths. Soils with gypsum and even gypsum rocks are very hard in their dry state. However, these soils and rock will experience remarkable dissolution upon wetting.

The dissolution phenomenon, which takes place in soils that contain gypsum, creates different geotechnical problems within the soil’s profile, along with foundation issues for structures …


Mathematical Modeling Of Lithium-Sulfur Batteries, Niloofar Kamyab Oct 2020

Mathematical Modeling Of Lithium-Sulfur Batteries, Niloofar Kamyab

Theses and Dissertations

Energy storage market transformed by utilization of lithium-ion batteries, will demand high and affordable deliverable energy in the near future which it would be impossible for the current employed technologies to meet those needs Among new generation of lithium batteries, high theoretical energy density, good low-temperature performance, and abundance of inexpensive nontoxic raw material, make the lithium-sulfur batteries (LiS) a promising candidate to outperform the current lithium-ion batteries and transform the technology of the future. However, the problems and challenges that LiS batteries are currently facing with, which stem from the inherent complex mechanism of these cells, are hindering their …


Acoustic And Ultrasonic Beam Focusing Through Aberrative And Attenuative Layers, Hossain Ahmed Oct 2020

Acoustic And Ultrasonic Beam Focusing Through Aberrative And Attenuative Layers, Hossain Ahmed

Theses and Dissertations

Ultrasonic nondestructive evaluation (NDE) is a well-established technique to assess material properties and material state in noninvasive way. However, conventional NDE technologies are limited by the thick top coatings over the structure and, therefore, require time consuming removal and replacement of the coatings to perform the inspection. In biological application, although ultrasonic NDE is a safer method in compared to other radioactive non-invasive techniques, aberration of acoustic beams is more common as it encounters multiple tissue layers of complex geometry with nonhomogeneous properties. These limit the use of ultrasonic NDE in engineering and biological applications. To alleviate this problem, recently …