Engineering Commons^™

Agricultural Drought Assessment Based On Multiple Soil Moisture Products, Jongjin Baik, Muhammad Zohaib, Ungtae Kim, Muhammad Aadil, Minha Choi

Civil and Environmental Engineering Faculty Publications

In this study, we evaluated three soil moisture (SM) products (Advanced Microwave Scanning Radiometer-2 [AMSR2], Advanced SCATterometer [ASCAT], and European Reanalysis Interim [ERA-interim]) across Australia in four climate zones by comparing against the Australian Water Resources Assessment-Landscape (AWRA-L) SM products from July 2012 to June 2017. The ASCAT SM indicated better performance than other SM products over Australia. To evaluate the applicability and reliability for monitoring agricultural drought, an agricultural drought index, the Soil Water Deficit Index, was estimated from three SM products and compared with three commonly-used drought indices (atmospheric water deficit [AWD], Evaporative Stress Index, and Reconnaissance …

A New Design Methodology Of Reinforced Concrete Squat Shear Walls For Ductile Seismic Behavior And Predictable Shear Strength, Ghassan S. Almasabha

Civil Engineering Dissertations - Archive

Reinforced concrete (RC) squat walls (with a height-to-length ratio of 2.0 or less) have high strength and stiffness which makes them a popular seismic force-resistant system for buildings and nuclear power plants. However, extensive studies on squat shear walls showed that squat walls have limited drift ductility because a flexural yielding mechanism is difficult to achieve, thereby undermining the role of squat walls as structural fuse members in earthquake-resisting structures. This research proposes a new design methodology of squat walls for ductile seismic behavior. While ACI 318-19 requires a mesh of steel bars to reinforce squat walls, the proposed design …

Remaining Service Life Estimation And Probabilistic Analysis Of Reinforced Concrete Sewer Pipeline Systems, Pardis Moamaei

Civil Engineering Theses - Archive

The serviceability and structural performance of reinforced concrete pipes could deteriorate for many reasons. The loss in structural capacity and other structural operations may drastically affect the surrounding environment, public health and the economy. This research is directed towards the estimation of remaining service life, and to evaluate the level of risk of failure of reinforced concrete sewer pipes (RCSP) that are subjected to continuing corrosion due to sulfide attack that in turn leads to loss of pipe thickness caused by excessive deterioration along the pipe’s interior wall. In order to estimate the remaining service life, reliability theory is used …

Improving Post Processing Of Ensemble Streamflow Forecast For Short-To-Long Ranges: A Multiscale Approach, Babak Alizadeh

Civil Engineering Dissertations - Archive

A novel multi-scale post-processor for ensemble streamflow prediction, MS-EnsPost, and a multiscale probability matching (MS-PM) technique for bias correction in streamflow simulation are developed and evaluated. The MS-PM successively applies probability matching (PM) across multiple time scales of aggregation to reduce scale-dependent biases in streamflow simulation. For evaluation of MS-PM, 34 basins in four National Weather Service (NWS) River Forecast Centers (RFC) in the US were used. The results indicate that MS-PM improves over PM for streamflow prediction at a daily time step, and that averaging the empirical cumulative distribution functions to reduce sampling uncertainty marginally improves performance. The performance …

Long-Distance And Broad-Band Aerial Communication Using Directional Antennas: Theory, Implementation, And Applications, Songwei Li

Electrical Engineering Dissertations - Archive

Unmanned aerial vehicles (UAV) have found broad civilian applications. However, existing commercial usages are limited to single UAVs. To facilitate commercial multi-UAV applications, robust UAV-to-UAV communication with long-distance and broad-band capabilities is critical. Such a communication architecture should not rely on ground infrastructure support, and hence can be applied whenever needed in scenarios where infrastructures are not available. It is foreseen to have extensive usages in a wide spectrum of commercial UAV applications such as emergency response, remote sensing, and nondestructive health monitoring. A promising solution for such a communication architecture is aerial communication using directional antennas (ACDA). We developed …

Analytical And Numerical Modeling Of Externally Heated Geothermal Bridge Deck, Mandakini Chowdhury

Civil Engineering Theses - Archive

Bridge icing is a severe safety concern for travel during winter months in the United States. Ice on bridges form quicker than roads, as the bridge is exposed to wind on all its surfaces. The underlying problem of bridge icing is loss of friction between the vehicle wheel and the pavement surface due to slippery nature of ice. Hence, the solution is to increase the friction between the above-mentioned surfaces. The most commonly adopted solution is application of sand, salt or other granular materials on the roadway. However, due to corrosive nature of the salts, the durability of the infrastructure …

User Syndication Using Speech Rhythm, Faisal Z H Alnahhas

Civil Engineering Theses - Archive

In recent years we have seen a variety of approaches to increase security on computers and mobile devices including fingerprint, and facial recognition. Such techniques while effective are very expensive. Voice biometrics, specifically speech rhythm, is a method that has been drawing attention and growing in recent years. Unlike other methods, it requires little to no additional hardware installed on a device for it to work accurately. Speech rhythm utilizes the device's built-in microphone, and analyzes speakers based on features of their speech. In this work we leverage the existing hardware and simply add an efficient layer of software to …

Solarpede: An Untethered Micro Robot Powered By Light., Jordan Fredrick Klotz

Electronic Theses and Dissertations

Micro-Robotics looks to implement robotics principles at a small scale and has gained popularity in recent decades as a gateway to new research areas such as micro-factory applications. The SolarPede is a second-generation, cm-scale micro-crawler designed for such micro factory applications which is equipped with a legged locomotion system and an electronic backpack. The SolarPede is an evolution of its predecessors and features power and signal conditioning capabilities, gait pattern generation, and Bluetooth connectivity. The components which make up SolarPede have been full validated and tested, and its systems have been realized in the form of a body made from …

Structure And Properties Of Zno-Zns Heterostructures, Sanchali Das

Graduate Theses/Dissertations

Heterostructures consisting of at least two layers of dissimilar materials have always been well studied due to potential applications in nano-electronic and optoelectronic devices. In this study, I have investigated the structural and physical properties of zinc oxide -zinc sulfide (ZnO-ZnS) based heterostructures of thin films and core-shell nanoparticles. Pulsed laser deposition technique was employed to grow ZnO thin film on sapphire substrate. ZnO-ZnS heterostructures were obtained using hydrothermal synthesis where thiourea has served as a precursor solution for the source of sulfur. X-ray diffraction analysis on the parent and the sulfidized samples gives the information about the crystallinity and …

Synthesis Of Amorphous Hydrogenated Boron Carbide From Orthocarborane Using Argon Bombardment: A Reaxff Molecular Dynamics Study, Nirmal Baishnab

Graduate Theses/Dissertations

In this study, the synthesis process of a-B­_xC:H_y using argon bombardment from the orthocarborane precursor was modeled by using reactive molecular dynamics (MD). Utilizing the MD simulations, the formation of free radicals as a result of ion bombardment was identified and quantified. Then, the densification process that is aided by the mixture of free radicals and orthocarborane was analyzed. The densification process by creating the initial structure composed of free radicals and orthocarborane with active sites created by partially removing some of the hydrogen atoms from the icosahedral cage was also modelled. Overall, a better understanding of …

Mining Semantic Knowledge Graphs To Add Explainability To Black Box Recommender Systems, Mohammed Alshammari, Olfa Nasraoui, Scott Sanders

Faculty and Staff Scholarship

Recommender systems are being increasingly used to predict the preferences of users on online platforms and recommend relevant options that help them cope with information overload. In particular, modern model-based collaborative filtering algorithms, such as latent factor models, are considered state-of-the-art in recommendation systems. Unfortunately, these black box systems lack transparency, as they provide little information about the reasoning behind their predictions. White box systems, in contrast, can, by nature, easily generate explanations. However, their predictions are less accurate than sophisticated black box models. Recent research has demonstrated that explanations are an essential component in bringing the powerful predictions of …

Uncovering Underlying Features For State Transition Modeling, Ashkan Farahani

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Modeling of a dynamic system is the representation of the interconnectivity of system state variables and their evolutionary trajectory over time. In this dissertation, the terminology “state transition modeling” refers to a situation when the system state transitions and its evolution is unknown and needs to be estimated. There are situations in many application settings where one does not simply observe the behavior of the system, but also has a desire to take action, intervene, and manipulate one or more system variables, and is interested in seeing the causal effect of the intervention. These interventions within a purely observational setting, …

Studies Of Dislocation Density Quantification Via Cross-Correlation Ebsd, Samuel Searle Friedbaum

Theses and Dissertations

One conventional method for studying dislocations uses the Transmission Electron Microscope (TEM), a complex and expensive piece of equipment which requires extensive specimen preparation in order to thin the specimens to electron transparent thickness. Newer High Resolution Electron Backscatter Diffraction (HREBSD) methods of determining geometrically necessary dislocation content via cross-correlation promise to be able to produce estimates of the dislocation density of the sample over a larger area with considerably less preparation time and using a much more accessible instrument. However, the accuracy of the new EBSD technique needs more experimental verification, including consideration of possible changes in the specimen …

Wireless Antenna Detection Of Electrostatic Discharge Events, Allen Andersen, Jr Dennison

Journal Articles

Wireless intraspacecraft communication technology is being developed for signal transfer on space missions to save weight and simplify the design. One consideration for this new technology is its interaction with space environmentinduced electrostatic discharges (ESDs). The short time scales of spacecraft ESD events result in broad frequency band signals that can interact with high-frequency wireless antennas. These interactions present a source of signal noise. However, they also present a possibility of in-flight wireless ESD monitoring. We present laboratory measurements of arcing on common spacecraft insulators using commercially available single-band 2.4-GHz and dual-band 2.4-/5.8-GHz Wi-Fi antennas. These wireless detections are shown …

Mars Knot Positioning And Global Optimization, Xinglong Ju

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Multivariate adaptive regression splines (MARS) is a statistical modeling approach with wide real-world applications. In the MARS model building process, knot positioning is a critical step that potentially affects the accuracy of the final MARS model. Identifying well-positioned knots entails assessing the quality of many knots in each model building iteration, which requires much computation efforts. By exploring the change in the residual sum of squares (RSS) within MARS, we find that local optima from previous iterations can be very close to those of the current iteration. In our approach, the prior change in RSS information is used to “warm …

Analyzing Collaboration In Food Assistance Networks Using Agent-Based Modeling, Joyita Mostafa

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

To address the issue of food insecurity, many small independent agencies, known as food pantries, collect and distribute donated food to food-insecure clients. However, the supply of donated food varies significantly from week to week, leading to frequent mismatches in supply and demand. One approach to addressing this problem is to facilitate greater food pantry collaboration, such that they are able to balance supply and demand among themselves. However, their interpersonal relationships and the additional costs associated with transshipments can be a barrier to collaboration. The objective of this research is to use modeling to gain a better understanding of …

Optimal Control Strategies And Reinforcement Learning For Dynamical Multiagent Systems In Graphical Games, Victor Gabriel Lopez Mejia

Electrical Engineering Dissertations - Archive

As the number of autonomous agents increases in industrial and urban areas, the development of formal protocols to analyze their behavior as they interact with each other becomes of central interest in control systems research. Each agent in this setting is interested in completing a specific task with considerations of an optimal performance. Game theory has become one of the most useful tools in multiagent systems analysis due to its rigorous mathematical representation of optimal decision making. The analysis of dynamical systems has been developed in the branch of game theory regarded as differential games. The ser of graphical games …

Turbinat E Hidrocentraleve Dhe Analiza E Efiçencës Tek Hidrocentralet E Vogla Dhe Të Mëdha, Edon Neziri Neziri

Theses and Dissertations

Energjia elektrike paraqet një nga burimet ekzistenciale të aktiviteteve dhe veprimtarisë njerëzore. Burimet energjetike janë të ndryshme, siç janë edhe mënyrat, pajisjet dhe stabilimentet për gjenerimin e saj. Shfrytëzimi i burimeve energjetike nga lëndë të ripërtëritshme, e në veçanti shfrytëzimi i burimeve hidrike përmes veprave inxhinierike të quajtura hidrocentrale sot paraqet një rëndësi të veçantë jo vetëm në shkallë vendi por edhe më gjerë. Ky punim diplome për përfundimin e nivelit të parë të studimeve (bachelor) ka për qëllim të nxjerrë në pah disa karakteristika të turbinave që përdoren në hidrocentrale, si dhe të jep rezultatet në lidhje me analizën …

Increasing The Functionality Of Additive Manufacturing Through Atmospheric Microplasma And Nanotechnology, Alexander Jon Ulrich

Doctoral Dissertations

Additive Manufacturing (AM) has been changing the manufacturing landscape for the last 20 years. As the interest and demand for both polymer and metal-based 3D printing has grown, the materials and machines used have increased in capabilities. Despite the growth and advancement, there are still a large number of improvements that can be made to add functionality to 3D printers. Metal AM, a subcategory of 3D printing, has garnered much attention among industrial applications with large companies such as General Electric trying to implement the technology to increase innovative designs for motors. Some of the limitations on AM have to …

Development Of A Low Profile, Endoscopic Implant For Long Term Brain Imaging, Benjamin Scott Kemp

Doctoral Dissertations

The increased public awareness of concussion and traumatic brain injury has motivated continued research into the brain, its functions, and especially its response to injury, with a focus on improving the brain’s repair capabilities. However, due to the critical nature of the tissue, it is currently difficult for researchers to acquire high resolution images below the cortex without sacrificing a lab animal. Sacrificing an animal greatly reduces the amount of data that can be obtained from it, making longitudinal studies unappealing or unfeasible because a large number of animals is needed to obtain useful data over multiple time points. Additionally, …

Migration And Electropolymerization Of Methyl Methacrylate In Hardened Cement Paste Via Electrokinetic Treatment, Xi Xie

Doctoral Dissertations

Porous concrete structures are susceptible to the intrusion of chemical species, such as sulfates, chlorides, and carbon dioxide. Many technologies have been developed to repair or rehabilitate damaged concrete. These include cathodic protection, corrosion inhibitor addition, or the use of coatings and sealers. In recent years, a developing technology, electrokinetic nanoparticle treatment, has been shown to reduce concrete porosity, increase strength, promote corrosion resistance, and extend durability. This dissertation was conducted to explore a novel treatment to reduce the porosity of concrete via the application of electrokinetic transportation and electro-initiated polymerization of methyl methacrylate (MMA).

Potassium persulfate (PSP) was used …

Foot-Controlled Supernumerary Robotic Arm: Foot Interfaces And Human Abilities, Brandon William Rudolph

Graduate Theses - Mechanical Engineering

A supernumerary robotic limb (SRL) is a robotic limb that can act as an extra arm or leg for a human user. An unsolved issue with SRLs is how to operate them well. One possibility is to control an SRL with the foot, which offers the benefit of a third arm because the user’s arms remain unoccupied. While hand interfaces are common, foot interfaces are not well understood. Developing a good foot interface is challenging because of differences between feet and hands, such as the larger inertia of the leg. This thesis presents work to determine some design principles for …

The Axisymmetric Harmonic Element Including Gyroscopic Effects: A Complete Derivation, Zachary Charles Glick

Graduate Theses - Mechanical Engineering

Various types of finite elements have been used in the prediction of critical speeds of turbomachinery. Among these, axisymmetric harmonic elements provide both accurate natural frequency prediction and computational speed. Yet, a full derivation of such an element including gyroscopic effects is not widely available in the relevant literature. In this work, the finite elements for rotordynamics available in the literature are reviewed. Derivations necessary for the axisymmetric harmonic element mass, gyroscopic damping, and stiffness matrices and the equations of motion are clearly expounded using Hamilton’s principle. The formulation is applied to two model shafts, and the comparison of results …

Effect Of Modified Moisture Barriers On Slopes Stabilized With Recycled Plastic Pins, Anuja Sapkota

Civil Engineering Dissertations - Archive

High plasticity expansive clayey soils are prone to repeated swelling and shrinkage due to cyclic climatic variations. These variations lead to desiccation cracks that act as pathways for rainfall intrusion into the slope, and lead to increased moisture content. The increase in the moisture content of the soil generates considerable hydrostatic pressure, which can cause pavement distress and shallow slope failure. Previously, failed slopes in North Texas were repaired by the UTA research team using only recycled plastic pins, which increase the stability of the slope but do not improve the performance of the pavement shoulder or limit the intrusion …

Chemical Stabilization Of Expansive Soils Using Liquid Ionic Soil Stabilizers (Liss), Shi He

Civil Engineering Dissertations - Archive

Traditional soil stabilizers such as lime and cement are widely used to reduce swell and shrinkage behavior and enhance strength properties of expansive soils through the formation of cementitious products. However, the manufacturing process of these calcium-based stabilizers, such as lime and cement, need large amounts of water and emit gases such as CO, CO2, NOx, and SO2 that are harmful to the environment. Hence, environmentally-friendly techniques are often sought out by the civil infrastructure industry (Puppala et al. 2018a, 2019b, George et al. 2019a, Congress and Puppala 2019). In this research, an alternative stabilizer termed as liquid ionic soil …

Performance Of Precast Concrete Bridge Girders With Externally Bonded Anchored Cfrp, Tariq Tariq Al Jaafreh

Civil Engineering Dissertations - Archive

Repair with Carbon Fiber Reinforced Polymer (CFRP) has become a topic of great interest to engineers in the last two decades. Fiber Reinforced Polymer (FRP) is considered as one of the most popular and practical solutions for strengthening and retrofitting civil structures, including bridge girders. Several past studies indicated that a significant increase in strength and stiffness can be achieved by using this technology; however, the major drawback of this repairing method is debonding. This research investigated the flexural behavior of simulated lateral damaged pre-stressed concrete bridge girders. Five Tx28 girders were tested up to failure, where 4 of them …

Evaluation Of Model Uncertainties In Lrfd Calibration Process Of Drilled Shaft Axial Design, Mohammad Rakib Hasan

Civil Engineering Dissertations - Archive

The Federal Highway Administration (FHWA) released a policy in 2000 that required all new federally funded bridges to be designed using the AASHTO LRFD specifications by October 2007. The transition from ASD to LRFD posed a challenge due to the lack of area specific resistance factors. Though several studies were performed to calibrate area specific resistance factors, they did not improve from the resistance factors suggested in AASHTO 2012. The objective of this study is to analyze the uncertainties in LRFD calibration and to calibrate more accurate and improved resistance factors. A drilled shaft load test database from Mississippi and …

Isentropic Efficiency And Theoretical Analysis Of The Planetary Rotor Expander, Joseph L. James

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Expanders allow pressurized fluids to undergo a pressure decrease in a controlled environment via volumetric growth to extract fluid energy. There are many types of expanders, and the objective of this thesis is to model the efficiencies of the planetary rotor expander (PRE), a century-old design undeveloped due to insufficient manufacturing capabilities (until recently). Geometric relationships are derived and mathematical models are generated to determine the efficiency of the PRE as a function of design variables. Two industrially relevant case studies show that, to maximize isentropic efficiency, the planetary rotor expander (PRE) rotational frequency is maximized and rotor geometry optimized.

Design Of Capacitive Wireless Power Transfer Systems With Enhanced Power Density And Stray Field Shielding, Ujjwal Pratik

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wireless power transfer is becoming relevant today because of its effectiveness and convenience. It has been employed into consumer electronics such as cellular charging and electric vehicle charging. In general, inductive wireless power transfer (IPT) is mostly used for WPT. IPT requires coils and power transfer enhancing material such as ferrite to transfer power. However, Capacitive wireless Power Transfer (CPT) appears as an alternative because it requires cost effective and light metal plate couplers. Among CPT couplers, Vertical (stacked) Four-Plate Coupler (V4PC) structure offers the advantage of higher input and output self-capacitances, rotational misalignment.

Safety is one of the most …

Parametric Study Of Mixture Component Contributions To Compressive Strength And Impact Energy Absorption Capacity Of A High Strength Cementitious Mix With No Coarse Aggregate, Md. Abdullah Al Sarfin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research project has been undertaken to produce and characterize the behavior of High Strength Cementitious Mix (HSCM), which has considerably higher compressive strength compared to conventional concrete. Components of HSCM are cement, silica fume, sand, water, and high range water reducer. The material is tested for compressive strength and impact energy absorption capacity while the amount of above mentioned components are varied parametrically. The effect of these parameters are extensively studied and trends are reported. Finally, this research projects attempts to find correlations among compressive strength, compressive toughness, and impact toughness. Limitations of the experimental program are discussed and …