Engineering Commons^™

From Leanstore To Learnedstore: Using A Learned Index To Improve Database Index Search, Sujit Maharjan

Computer Science and Engineering Faculty Publications - Archive

In the realm of database systems, optimizing B+-tree index performance is of paramount importance to overall database performance. LeanStore, a high-performance OLTP storage engine, has extensively optimized its in-memory B+-tree component as well as its B+-tree -indexed database on the disk. However, B+-tree's lookup time increases linearly with the tree height. This is especially problematic when all or part of its lookup path is on the disk. Recently proposed learned index technique has the potential to significantly improve the performance of the B+-tree -based index by predicting location of the search key, instead of the level-by-Ievel path walk. However, this …

Preclassic Environmental Degradation Of Lake Petén Itzá, Guatemala, By The Early Maya Of Nixtun-Ch’Ich’, Brooke A. Birkett, Jonathan Obrist-Farner, Prudence M. Rice, Wesley G. Parker, Peter M.J. Douglas, Melissa A. Berke, Audrey K. Taylor, Jason H. Curtis, Benjamin Keenan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Paleolimnological Evidence Indicates the Ancient Maya Transformed Terrestrial Ecosystems by Felling Forest Vegetation to Construct Large Civic-Ceremonial Centers and to Expand Agriculture. Human Settlements Influenced Lacustrine Environments But the Effects of Maya Activities on Aquatic Ecosystems Remain Poorly Studied. Here We Analyzed a Sediment Core from Lake Petén Itzá, Guatemala, to Infer Paleoenvironmental Changes Resulting from Maya Occupation of the Archaeological Site of Nixtun-Ch'ich'. Increases in Charcoal and Fecal Stanol Concentrations Indicate Maya Occupation of the Candelaria Peninsula by the Late Early Preclassic Period. Geochemical Proxies Reveal a Period of Lake Ecosystem Alteration during Construction and Expansion of the City's …

Cnc Retrofits, Fabian Samano, Murat Askin, Daniel Lonczak, Zane Campise

Mechanical Engineering

The Boxford CNC Lathe is a machine used for educational purposes. The goal of the CNC Retrofits project is to improve the Boxford MT2’s performance and functionality to enable Mr. Lonczak to manufacture customized ballpoint pens. Within this Final Design Review (FDR) document, we present design updates since the CDR and implementation/assembly techniques. This work culminates in a solution to Mr. Lonczak’s needs which is analyzed in three subsystems: main control, spindle position tracking, and user interface. Within this report, we show the results of each subsystem’s verification process. These results prove that the design concept was met by describing …

Computationally-Driven Insights Into The Ligand Environments Of Materials For Catalysis And Separations, Stephen Vicchio

All Dissertations

Designing new catalytic and sorption materials is necessary to limit global temperature rise below 1.5 ◦C by 2050, while also meeting global energy demands. Climate change and energy production are not mutually exclusive; global population growth has direct impacts on global energy demands and climate. In both catalysis and adsorption applications, new technologies are needed to address these challenges. Catalysis can provide alternate, low-energy routes for converting low-value gases into higher-value chemical commodities, thus altering our current energy production. Likewise, new sorption materials can capture previously emitted CO₂ from decades of energy production from fossil fuels, thus helping to …

Statistical And Deep Learning Models For Reference Evapotranspiration Time Series Forecasting: A Comparison Of Accuracy, Complexity, And Data Efficiency, Arman Ahmadi, Andre Daccache, Mojtaba Sadegh, Richard L. Snyder

Civil Engineering Faculty Publications and Presentations

Reference evapotranspiration (ETo) is an essential variable in agricultural water resources management and irrigation scheduling. An accurate and reliable forecast of ETo facilitates effective decision-making in agriculture. Although numerous studies assessed various methodologies for ETo forecasting, an in-depth multi-dimensional analysis evaluating different aspects of these methodologies is missing. This study systematically evaluates the complexity, computational cost, data efficiency, and accuracy of ten models that have been used or could potentially be used for ETo forecasting. These models range from well-known statistical forecasting models like seasonal autoregressive integrated moving average (SARIMA) to state-of-the-art deep learning (DL) algorithms like temporal fusion transformer …

Thermal Resistance Characterization Of High-Voltage Sic Power Module, Landon Lemmons

Mechanical Engineering Undergraduate Honors Theses

Researchers within the University of Arkansas Electrical Engineering Research Department have embarked on a project aimed at enhancing the thermal performance of high-voltage power modules. To aid in the progress of this project, the design, and development of a thermal tester device are needed. The primary objective of this device is to determine the various thermal properties of high-voltage power modules that the electrical engineering department has developed. Additionally, the project aims to facilitate electrical loading tests on power modules and provide researchers with the means to calibrate the power module in terms of thermal load. This project also possesses …

Infrastructure Damage Detection Leveraging Advanced Ai Techniques, Yin Chao Wu

Civil Engineering Dissertations - Archive

The dissertation explores into structural damage identification and prediction through the application of machine learning. Firstly, it enhances impact echo delamination mapping by incorporating two signal image parameters—signal duration and starting time after zero-crossing. The research also explores the efficiency of machine learning concerning image resolution and the number of images. This approach refines the evaluation of bridge damage in field tests. Two crucial signal parameters are investigated: signal duration and signal starting time after the zero-crossing point. These parameters exert a direct impact on the frequency domain, a crucial metric in impact echo analysis. This metric discerns signals reflected …

Proactive Seismic Rehabilitation Decision-Making Model For Water Pipe Networks Under Network Uncertainties And Degradation, Abhijit Roy

Civil Engineering Dissertations - Archive

Past earthquakes have revealed that earthquakes disrupt the operations of underground water infrastructure systems. Assessment of the seismic vulnerability of underground water pipe networks plays a critical role in formulating preventive rehabilitation decision-making to ensure maximum serviceability after an earthquake event and avoid high repair costs. Although existing seismic vulnerability assessment methods and seismic rehabilitation decision-making models are sensitive to water pipe network uncertainties (e.g., uncertainties in nodal demand, reservoir head, and pipe roughness coefficient) and pipes’ degradation, the extent of the effects of the network uncertainties and pipes’ degradation on the postearthquake serviceability of the network and seismic rehabilitation …

An Experimental And Numerical Study Of Utilizing Steel Fiber And Gfrp In Bridge Decks Under Bending, Sam Kafaji

Civil Engineering Dissertations - Archive

The process of laying and tying conventional reinforcement is a time-consuming task when building a bridge deck, especially while ensuring the proper cover. To speed up the construction process, the bridge construction industry should look into replacing conventional reinforcing bars with steel fibers. This could be a significant breakthrough in bridge construction. Despite numerous experiments and research conducted on the bending strength of reinforced concrete decks, there are still several factors that require further exploration. This experiment focuses on utilizing steel fiber reinforced concrete (SFRC) in a multiple-span concrete bridge deck to investigate the opportunities of using SFRC as the …

Condition Assessment Of Reinforced Concrete Sanitary Sewer Pipelines Using Probabilistic Methods And Advanced Inspection Tools, Moein Ebrahimi

Civil Engineering Dissertations - Archive

Large sanitary sewer pipelines (SSPs) are the backbone of modern infrastructure. They carry wastewater from smaller lines to treatment plans; therefore, they are critical for public health and safety. According to the ASCE report card published in 2021, the condition rate of sanitary sewage networks in the United States is D+ (i.e., poor) (ASCE 2021). Therefore, frequent inspections of SSPs are crucial for performing a proper life cycle management strategy. New inspection technologies such as LiDAR have recently been employed for rapid condition assessment of SSPs. Because of the precision of LiDAR inspection data, it can not only measure hydraulic …

Temperature Gradient Effect On Solid-Liqid Interface Properties Of Al-Cu Alloy: A Molecular Dynamics Study, Prashant Kumar Jha

All Theses

Aluminum-copper (Al-Cu) alloys are widely used in the aerospace industry due to their favorable strength-to-weight ratio, good fatigue resistance, and corrosion resistance. These properties make Al-Cu alloys an excellent choice for aircraft structural components that require high strength and low weight. Additive manufacturing (AM), also known as 3D printing, has emerged as a promising processing method for Al-Cu alloys in aerospace manufacturing. AM enables the production of lightweight optimized geometries difficult to manufacture through conventional subtractive methods. AM also reduces material waste by only depositing material where needed in the part geometry. The rapid solidification conditions in AM processes motivate …

Experimental Study On The Impact Of Low Thermal Inertia Thermal Barrier Coatings On Ppci-Diffusion Gci Combustion, Kunal Vedpathak

All Theses

The application of thermal barrier coatings (TBCs) has been studied in homogenous charge compression ignition (HCCI), conventional diesel combustion (CDC), and spark ignition (SI). Gasoline compression ignition (GCI) combines the low soot and NOx emissions of HCCI with combustion controllability through fuel stratification. GCI has become an interesting prospect due to the reduction in gasoline consumption due to the electrification and hybridization of the light-duty sector. It can be used as a preferred combustion mode in heavy-duty engines to reduce emissions with minimal modifications. GCI exhibits better combustion efficiency than HCCI. Advances in material technology have combined low thermal conductivity …

Finite Element Analysis On Laser Sintering Of Ceramic Materials, Shardul Sharma

All Theses

Laser sintering of ceramics plays a vital role in advanced additive manufacturing due to its precise fabrication of complex ceramic structures, localized heating and microstructural control. It allows the production of complex and customized ceramic parts for applications such as the aerospace industry and biomedical devices. However, due to the high thermal gradients produced during the process, laser sintering technology faces fundamental challenges, such as thermal stresses and crack formation. Establishing a valid numerical model to guide the ceramic laser sintering process, which predicts the thermal and mechanical behavior of the component, is necessary.

In this work, the modified Skorohod-Olevsky …

Probabilistic Multivariate Time Series Forecasting And Robust Uncertainty Quantification With Applications In Electricity Price Prediction, Jie Han

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Electricity price forecasting (EPF) is a crucial task for market participants seeking informed decisions in day-ahead electricity markets. The increasing penetration of stochastic renewable energy and the deregulation of electricity markets pose challenges to electricity price forecasting. Given the dependence of electricity prices on stochastic factors such as weather conditions, market dynamics, and customer behaviors, deterministic forecasting methods offer limited insight into the potential future states of energy prices in highly stochastic markets. In this study, a transformer-based electricity price forecasting (TDEPF) model was developed, utilizing a two-step training process and demonstrating superior performance compared to typical RNN models. Subsequently, …

Sea Level Rise And The Drivers Of Daily Water Levels In The Sacramento-San Joaquin Delta, H. Baranes, Steven Dykstra, D. A. Jay, S. A. Talke

Civil and Environmental Engineering Faculty Publications and Presentations

Water levels in deltas and estuaries vary on multiple timescales due to coastal, hydrologic, meteorologic, geologic, and anthropogenic factors. These diverse factors increase the uncertainty of, and may bias, relative sea level rise (RSLR) estimates. Here, we evaluate RSLR in San Francisco Bay and the Sacramento-San Joaquin Delta, USA by applying a physics-based, nonlinear regression to 50 tide gauges that determines the spatially varying controls on daily mean water level for water years 2004–2022. Results show that elevated river flow and pumping (99th percentile) raise water level up to 6 m and lower it up to 0.35 m, respectively, and …

Construing Children’S Perceptions Of Ideal Learning Spaces Based On Personal Construct Theory, Rawan Natheer Abdel Rahman

Theses

Learning is an intrinsic aspect of human experience, predominantly shaped by interactions within the socio-physical environment, including engagements with educators, peers, and the built surroundings. The design and character of these learning spaces influence children's cognitive, perceptual, and motor development while also embodying different pedagogical philosophies. Therefore, designing these spaces to align with educational shifts and enhance learning experiences requires a deep understanding of learner’s needs and perceptions. With the COVID-19 pandemic necessitating a shift to home-learning, there arose a unique opportunity to explore children’s perception of ideal learning spaces as they experienced both home and school settings. This research …

Numerical Investigation Of Lead Free Cs2tibr6 Based Perovskite Solar Cell With Optimal Selection Of Electron And Hole Transport Layer Through Scaps-1d Simulation, Hironmoy Karmaker, Ayesha Siddique, Barun K. Das

Research outputs 2022 to 2026

Halide-based perovskite has several advantages, including high efficiency, ease of manufacture, and low cost. In general, hazardous lead (Pb) is used in perovskite solar cells as an absorber layer, while polymer, which is unstable in nature used as the electron/hole transport layer. Despite its appealing characteristics, the device uses of lead and degradable components must be addressed. Lead-free titanium-based inorganic perovskite solar cells (PSCs) have drawn strong scientific interest in recent years in order to reduce the possibly detrimental effects of lead on the environment. Titanium is non-toxic, robust, inexpensive, and widely available when compared to other elements. The performance …

Metal Organic Frameworks With Carbon Black For The Enhanced Electrochemical Detection Of 2,4,6-Trinitrotoluene, Shaghraf Javaid, Muhammad R. Azhar, Xinyu Li, Juliette I. Phillips, Tanveer Hussain, Hussein Abid, Jun Chen, Xiaobo Ji, Debbie S. Silvester

Research outputs 2022 to 2026

The sensing of explosives such as 2,4,6-trinitrotoluene (TNT) directly at an explosion site requires a fast, simple and sensitive detection method, to which electrochemical techniques are well suited. Herein, we report an electrochemical sensor material for TNT based on an ammonium hydroxide (NH4OH) sensitized zinc-1,4–benzenedicarboxylate Zn(BDC) metal organic framework (MOF) mixed with carbon black on a glassy carbon electrode. In the solvent modulation mechanism, by merely changing the concentration of NH4OH during synthesis, two Zn(BDC) MOFs with novel morphologies were fabricated via a hydrothermal approach. The as-prepared MOFs were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier …

Space-Time-Frequency Characterization In Electromagnetic Near-Field Scanning: A Data-Driven Approach, Yanming Zhang, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Near-field scanning has become a widely used tool for diagnosing electromagnetic compatibility and electromagnetic interference issues. However, the transient signal of the device under test often contains multiple frequency bands and exhibits nonstationarity, which poses a challenge for near-field scanning analysis. To address this issue, this article presents a method for analyzing time-resolved near-field radiation based on multiresolution dynamic mode decomposition (MRDMD). The MRDMD approach recursively and hierarchically applies the traditional dynamic mode decomposition (DMD) method. The distribution of DMD eigenvalues determines the slow and fast modes in each level's decomposition, where the slow modes are preserved, and the fast …

Modeling And Simulation Of Flotation Reagents System In Anionic Reverse Iron Oxide Flotation At Different Temperatures, Ying Hou, Ahmed Sobhy

Mining Engineering Faculty Research & Creative Works

Removal of quartz from iron ore was accomplished industrially via an anionic reverse flotation technique. However, in that kind of flotation, the interaction of the flotation reagents with the components of the feed sample makes the flotation a complicated system. Thus, the selection and optimization of regent dosages at various temperatures were performed using a uniform experimental design to estimate the optimum separation efficiency. Besides, the produced data as well as the reagent system were mathematically modeled at different flotation temperatures, and the graphical user interface GUI of MATLAB was conducted. The advantage of this procedure is that the user …

Graphene-Based Chemiresistor Sensors For Drinking Water Quality Monitoring, Mason Mcgarrity, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

Monitoring the quality of drinking water is a crucial responsibility for all water infrastructure networks, as it guarantees access to clean water for the communities they serve. With water infrastructure deteriorating due to age and neglect, drinking water violations are on the rise in the US, underscoring the need for improved monitoring capabilities. Among the different sensor technologies, graphene-based Chemi resistors have emerged as a promising technology for water quality monitoring due to advantages such as simple design, sensitivity, and selectivity. This review paper provides an overview of recent advances in the development of graphene-based Chemi resistors for water quality …

Graphical Analysis And Revamping Of Crude Distillation Units Under Variable Operational Scenarios, Amany G. Abo-Mousa, Dina A. Kamel, Hany A. Elazab, Mamdouh A. Gadalla, Mai K. Fouad

Chemical and Biochemical Engineering Faculty Research & Creative Works

Energy Cost Represents a Significant Part of the Total Operating Costs of Many Processing Units. Crude Distillation is an Energy Intensive Process. Energy Integration is a Typical Solution to Reduce Heating and Cooling Utilities through Maximizing the Target Temperature of Crude Oil Streams Before Entering the Furnace. over the Past Few Decades, Significant Progress Has Been Made in Energy Integration Methods Including Pinch Technology and Mathematical Programming Approaches. Very Recently, Graphical Techniques Have Been Developed for Revamping Studies and Energy Analysis. Such Diagrams Are Valuable in Energy Targeting to Identity Energy Inefficiencies and Are Key to Potential Modifications for Maximum …

A Review On Liquid Flow Through Low-Density Fibrous Porous Media, Hossein Abedsoltan

Chemical and Biochemical Engineering Faculty Research & Creative Works

This review focuses on studying liquid flow through low-density fibrous porous media, particularly tissue grades of papers. It discusses experimental designs, factors affecting liquid flow, and various versions of the Lucas-Washburn equation and permeability expressions used to estimate liquid flow in these media. While a comprehensive model for liquid flow in these materials is lacking due to their structural complexity, numerous experimental methods have been developed to determine absorption properties, particularly for wiping and cleaning liquids. The review covers these methods, many of which are proposed by standard organizations. It is a valuable reference for scientists interested in understanding the …

Covid-19 And The Chemical Industry: Impacts, Challenges, And Opportunities, Hossein Abedsoltan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The COVID-19 pandemic imposed unparalleled challenges for the chemical industry, leading to disruptions in supply chains and demand dynamics. This period of crisis tested the adaptability and resilience of global chemical companies. Despite the challenges, the chemical industry exhibited remarkable innovation, collaboration, and adaptability. It demonstrated its capacity to respond swiftly and effectively to societal needs. Key lessons emerged, emphasizing the importance of diversifying supply chains, implementing scenario planning, and embracing digitalization for enhanced preparedness. As the world progresses toward recovery, the chemical industry is poised to leverage the valuable lessons learned. Industry 4.0 adoption, agile decision-making, and collaborative efforts …

Comparative Evaluation Of Caries Prevalence Among Group Of Egyptian Adolescents Using Dmfs And Icdasii Methods: A Cross-Sectional Study, Mohamed H. Zaazou, Dalia Y. Zaki, Ali Abdelnabi, Tamer M. Hamdy, Reham S. Saleh, Shahinaz N. Hassan, Zeinab M. Zaki, Lamiaa M. Moharam

Chemical and Biochemical Engineering Faculty Research & Creative Works

Background: Limited data is available regarding the prevalence of dental caries as a chronic disease among adolescents using different caries assessment indices. The aim of this study was to compare and describe the prevalence of dental caries among group of Egyptian students using two caries assessment indices: DMFS and ICDAS II. Methods: This descriptive, cross-sectional epidemiological study included 2760 public secondary school students with age range from 15 to 18 years with permanent dentition and good general health. Presence of; retained teeth, congenital or developmental anomalies in the permanent dentition, orthodontic treatments, systematic conditions, smoking and general health problems were …

Drinking-Water Fluoridation As An Example Of The Nurse + Engineer Fostering Informed Decisions And Actions, Daniel B. Oerther, Sarah Oerther

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Atmospheric-Moisture-Induced Polyacrylate Hydrogels For Hybrid Passive Cooling, Roisul Hasan Galib, Yanpei Tian, Yue Lei, Saichao Dang, Xiaole Li, Arief Yudhanto, Gilles Lubineau, Qiaoqiang Gan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Heat stress is being exacerbated by global warming, jeopardizing human and social sustainability. As a result, reliable and energy-efficient cooling methods are highly sought-after. Here, we report a polyacrylate film fabricated by self-moisture-absorbing hygroscopic hydrogel for efficient hybrid passive cooling. Using one of the lowest-cost industrial materials (e.g., sodium polyacrylate), we demonstrate radiative cooling by reducing solar heating with high solar reflectance (0.93) while maximizing thermal emission with high mid-infrared emittance (0.99). Importantly, the manufacturing process utilizes only atmospheric moisture and requires no additional chemicals or energy consumption, making it a completely green process. Under sunlight illumination of 800 W …

Brunet: Disruption-Tolerant Tcp And Decentralized Wi-Fi For Small Systems Of Vehicles, Nicholas Brunet

Master's Theses

Reliable wireless communication is essential for small systems of vehicles. However, for small-scale robotics projects where communication is not the primary goal, programmers frequently choose to use TCP with Wi-Fi because of their familiarity with the sockets API and the widespread availability of Wi-Fi hardware. However, neither of these technologies are suitable in their default configurations for highly mobile vehicles that experience frequent, extended disruptions. BRUNET (BRUNET Really Useful NETwork) provides a two-tier software solution that enhances the communication capabilities for Linux-based systems. An ad-hoc Wi-Fi network permits decentralized peer-to-peer and multi-hop connectivity without the need for dedicated network infrastructure. …

Decentralized Machine Learning On Blockchain: Developing A Federated Learning Based System, Nikhil Sridhar

Master's Theses

Traditional Machine Learning (ML) methods usually rely on a central server to per-
form ML tasks. However, these methods have problems like security risks, data
storage issues, and high computational demands. Federated Learning (FL), on the
other hand, spreads out the ML process. It trains models on local devices and then
combines them centrally. While FL improves computing and customization, it still
faces the same challenges as centralized ML in security and data storage.

This thesis introduces a new approach combining Federated Learning and Decen-
tralized Machine Learning (DML), which operates on an Ethereum Virtual Machine
(EVM) compatible blockchain. The …

Deep Ocean Vehicle Applications And Modifications, Nichole "Nikki" T. Arm

Master's Theses

This project had two primary goals: (1) to explore opportunities to further a deep-ocean vehicle’s reach using alternative pressure spheres, and (2) to implement an existing deep-ocean vehicle (lander) in active scientific research.

I gained a greater understanding of the limitations and design choices made for existing pressure spheres using Finite Element Analysis (FEA). My simplified FEA model predicted sphere failure for the existing 30% Fiber Glass 70% Nylon injection molded spheres at an external pressure of 3,954psi or 2,690m ocean-depth (only a 7.38% error compared to the tested minimum failure depth), so I determined it a valid model. I …