Engineering Commons^™

Examining Failures Of Kc-135s Using Survival Analysis, Vanessa I. R. Unseth

Theses and Dissertations

The United States Air Force manages an inventory of 396 KC-135 Stratotanker aircraft. With mission capability rates falling and total non-mission capability supply rates increasing, it is necessary to take a deeper look at recurrent failures. The study applies non-parametric and semi-parametric survival models to a dataset retrieved from LIMS-EV to look at the duration(s) until failure for the KC-135. Results of non-parametric models show cumulative failure rates increase as sorties or flight hours increase. In addition, semi-parametric models or Cox proportional hazards models with frailty confirm that locations or air bases are not associated with recurrent failures.

A Study On The Early Stages Of Degradation Of Multi-Component Alloy Surfaces In Extreme Environments Using The Multi-Cell Monte Carlo Method, Tyler D. Dolezal

Theses and Dissertations

A computational toolset is presented and used in two examples that examined the interactions between structural materials and their extreme environments. A multi-cell Monte Carlo algorithm was developed to generate thermodynamically realistic solid-state alloy systems. These structures served as the foundation upon which surface slab models were generated. The tedious procedure of generating surface slab models from bulk structures was automated. The tools were used to study the high temperature surface corrosion resistance of a high-entropy alloy, Al₁₀Nb₁₅Ta₅Ti₃₀Zr₄₀, and a nickel-based alloy, Ni₇₀Nb₁₀W₂₀, under …

Analysis Of The Perspective On Syrian Refugees By Neighboring Countries, Norma Ghanem

Theses and Dissertations

Mass migration destabilizes neighboring states, opening the way for fragile state exploitation by enemies, including those that could undermine U.S. national interests. This study investigates an area of the Levant region, specifically countries neighboring Syria, and analyzes their perspective on Syrian refugees for the time frame of 1 June 2019 - 30 June 2020. This analysis may assist in forming policy and creating strategies to address refugee related issues, both domestic and international. There are three main questions addressed. The first inspects dominant refugee framing, the second explores sentiment (dis)similarity within each country and across countries, and the third investigates …

Applied Agile Digital Mission Engineering For Cislunar Space Domain Awareness, Benjamin R. Williams

Theses and Dissertations

In the backdrop of an expansion into cislunar space and a digital transformation, the author synthesizes a methodology from agile system development, DE, ME, and MBSE processes, methods, and tools to develop a basic RA and DT for cislunar SDA mission and system design. The Agile DME methodology is used to conduct basic requirements analysis, develop a concept, understand cislunar physics, study scenario geometries, and perform analyses and the DT implements, executes, and accelerates research by integrating a descriptive tool with analytical and simulation tools. This research demonstrates the value of automated Modeling, Simulation, and Analysis (MSA) work flows and …

Potential Solution To Meet Growing Demands Of Refractory Metal: Selective Laser Melting Of Molybdenum-Tungsten Alloy, Jae Yu

Theses and Dissertations

Selective laser melting (SLM) of refractory metals has been of high interest in research due to the metals’ potential desirable characteristics in aeronautical and space applications. In particular, molybdenum and tungsten have been the focus of several studies in the search for high temperature and high strength purposes in applications like supersonic aircraft, re-entry vehicles, nuclear fission, power generation, and other space systems. However, there is still a significant knowledge gap to process defect-free alloys and making use of them in practical engineering functions. The aim of this study is to characterize the relationship between the microstructure and mechanical properties …

Cobalt Ferrite Nano-Composites For The Oxidation Of Phenols In Oil Refinery Wastewater, Amira Mohamed

Theses and Dissertations

Phenolic compounds have the tendency to persist in the environment over a long period making them a main source of concern because of their toxic characteristics towards humans and animals (Bruce et al., 1987). Therefore, existence of phenolic compounds in aquatic environment is unfavourable and as a result, many treatment techniques have been implemented to treat the wastewater produced from petroleum refineries. Petroleum refineries are among the top industries that produces significant quantities of high phenol concentration wastewater. Photo-catalysis is a promising and effective method to treat phenol present in oil refineries effluent. In this study, the photo-catalyst used is …

Advancing The Development Of Additively Manufactured Sequentially Cured Interpenetrating Polymer Networks, Rachael J. Ross

Theses and Dissertations

Recently vat photopolymerization (VPP), a type of additive manufacturing (AM), has the potential to be used for a variety of commercial and military applications due to the ability to make custom parts rapidly and with complex geometries. Many commercially available photopolymerizable resins consist of (meth)acrylate and epoxy functionality to ensure rapid cure time and minimal shrinkage. Today, researchers continue to find the optimal balance of (meth)acrylate/epoxy functionality in unique formulations and network configurations, such as interpenetrating polymer networks (IPN)s, to enhance processibility and the quality of the final printed part. This work explores the structure-property relationships of a set of …

Investigating Game-Based Instruction As A Tool For Engineering Ethics Education In A First-Year Engineering Program, Joshua B. Reed

Theses and Dissertations

Behaving ethically is a core foundation within engineering and is a necessity according to the National Society of Professional Engineers. Therefore, engineering ethics education has been increasingly encouraged within engineering curriculums in higher education. Many instructors have found it difficult to teach engineering ethics effectively using traditional strategies such as lectures. This has caused a trend toward more active learning strategies being researched and utilized within the engineering ethics space. One strategy that has been growing in popularity in instruction both inside and outside of engineering is game-based learning or using educational games with instruction to accomplish learning goals. To …

Flexural Strengthening Of Rc Slabs Using Near Surface Mounted Gfrp Bars, Sama Taha

Theses and Dissertations

Glass Fiber reinforced polymers (GFRPs) have been recently successfully used to increase reinforced concrete elements' strength. In general, FRPs have many advantages such as resistance to corrosion, and high strength-to-weight ratio. On the other hand, debonding from concrete may constitute a limitation to using GFRP bars; hence the increase in strength of RC elements strengthened using GFRP bars may be limited by this premature debonding failure mechanism.

This study aims to investigate the strengthening effect of GFRP bars on the capacity of RC slabs when subject to flexure loading. The work studies the use of different bonding lengths, diameters and …

Strengthening Of Long Rc Columns Using Near Surface Mounted Gfrp Bars, Ahmed Romaih

Theses and Dissertations

Many of the existing reinforced concrete (RC) columns are deficient because of numerous reasons such as increase in service loads, deterioration due to environmental attacks, errors in the design and/or construction phase or in the worst case, accidents. These elements require strengthening or repair. Different methods have been developed over the years for solving different rehabilitation problems. Recently, advanced composites used for external bonding in the form of fabrics or laminates have become an accepted method. The use of Fibre-Reinforced Polymers (FRPs) in this process is a promising technology, especially that these materials are corrosion-free. One of the new techniques …

Extractive Text Summarization On Single Documents Using Deep Learning, Shehab Mostafa Abdel-Salam Mohamed

Theses and Dissertations

The task of summarization can be categorized into two methods, extractive and abstractive summarization. Extractive approach selects highly meaningful sentences to form a summary while the abstractive approach interprets the original document and generates the summary in its own words. The task of generating a summary, whether extractive or abstractive, has been studied with different approaches such as statistical-based, graph-based, and deep-learning based approaches. Deep learning has achieved promising performance in comparison with the classical approaches and with the evolution of neural networks such as the attention network or commonly known as the Transformer architecture, there are potential areas for …

Rework Prediction On A Construction Site Through Bim & Ann Integration, Raghda Attia

Theses and Dissertations

Construction Rework is a common and widespread issue in the construction industry that has a detrimental impact on the project performance, whether in terms of schedule delay or cost overrun. Developments in Building Information Modelling (BIM) have aided in the resolution of coordination issues, which are thought to be one of the leading sources of rework particularly during the construction stage. Nevertheless, the majority of research has focused on resolving coordination issues during the design stage with minimum regard to the coordination issues that occur during the construction stage. In a BIM environment, the goal of this research is to …

A Quality Management System Implementation Framework For Contracting Companies In Egypt, Noha Elsokhn

Theses and Dissertations

Customer dissatisfaction due to low quality and performance in developing countries is more notable than technical construction failures. In order to enhance the corporate-level quality, which is reflected later in project-level metrics, quality management systems (QMS) are developed and applied. A quality management system (QMS) defines the organization's structure, processes, procedures, and responsibilities to achieve quality policies and objectives. Successful implementation of a QMS improves service quality, organization performance, and customer satisfaction. Previous research widely explored QMS implementation in different industries; only a few studies focused on the implementation and its influential factors in the construction industry, especially in developing …

Adding Temporal Information To Lidar Semantic Segmentation For Autonomous Vehicles, Mohammed Anany

Theses and Dissertations

Semantic segmentation is an essential technique to achieve scene understanding for various domains and applications. Particularly, it is of crucial importance in autonomous driving applications. Autonomous vehicles usually rely on cameras and light detection and ranging (LiDAR) sensors to gain contextual information from the environment. Semantic segmentation has been employed to process images and point clouds that were captured from cameras and LiDAR sensors respectively. One important research direction to consider is investigating the impact of utilizing temporal information in the domain of semantic segmentation. Many contributions exist in the field with regards to utilizing temporal information for semantic segmentation …

Design And Fabrication Of Nanostructured Electrodes For Complementary Electrochemical And Photoelectrochemical Water Splitting, Kholoud El Sayed Abousalem

Theses and Dissertations

Designing highly active, durable, and nonprecious electrodes for overall water splitting is of urgent scientific importance to realize sustainable hydrogen production. Accordingly, the need to search efficient energy production systems is of crucial necessity. In this thesis, two various systems for sustainable hydrogen production have been reported using electrochemical and photoelectrochemical pathways. In the first part of the thesis, electrochemical water splitting involving both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been established. To this end, an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn, Ni, Co phosphide catalysts directly on nickel foam via …

Project Leanness Score: A Machine Learning Approach, Julia Said

Theses and Dissertations

The construction industry is known to have several inadequacies in resource utilization leading to cost and schedule overruns. One of the popular recent methods that attempts to eliminate these inadequacies is lean construction principles, techniques and tools. Lean construction is a philosophy, backed with principles and tools, aiming at maximizing value, eliminating waste, optimizing efficiency, and seeking continuous improvement. Lean construction techniques (such as pull planning, just-in-time delivery, fail safe for quality, etc.) are widely researched and well developed. However, their implementation in construction sites is tricky as their success depends on several other factors such as the level of …

Mathematical Modeling And Optimization Of Water Efficiency In Residential Buildings, Mahmoud Amin

Theses and Dissertations

Water scarcity is a global issue that is rapidly worsening. The domestic sector is one of the fastest-growing segments of world water usage. Many researchers have explored various approaches to promote sustainable uses of water, with Greywater (GW) recycling and utilization of innovative plumbing fixtures among the methods presented to reduce freshwater consumption for domestic usage. Nonetheless, previous studies have dealt with both means independently, with limited analysis of the integrated effect of utilizing GW recycling with innovative plumbing fixtures, both on quality of supplied water, as well as on cost of the integrated system. Accordingly, this research aims at …

Camera And Lidar Fusion For Point Cloud Semantic Segmentation, Ali Abdelkader

Theses and Dissertations

Perception is a fundamental component of any autonomous driving system. Semantic segmentation is the perception task of assigning semantic class labels to sensor inputs. While autonomous driving systems are currently equipped with a suite of sensors, much focus in the literature has been on semantic segmentation of camera images only. Research in the fusion of different sensor modalities for semantic segmentation has not been investigated as much. Deep learning models based on transformer architectures have proven successful in many tasks in computer vision and natural language processing. This work explores the use of deep learning transformers to fuse information from …

Final Bid Price Estimation For Negotiated Contracts: Bargaining Game Theory Approach, Amr El Mahallaoui

Theses and Dissertations

The wide use of the low bid method by employers for awarding construction contracts has created an aggressively competitive environment among contractors in the construction industry. As a result, a contractor may resort to use a low mark-up percentage for his bid to increase his chances of winning, which may lead to losses and conflicts in case he is awarded the project. Additionally, a contractor who reaches the final negotiations stage for a certain project is faced by the dilemma of the minimum discount percentage he may need to offer to the employer that maximizes his chance to win the …

Impact Of Rapid Urbanization, Climate Change, And Drainage Design On Urban Flash Floods In New Cairo, Egypt, Bassma Taher Hassan

Theses and Dissertations

Urban flooding is considered one of the most hazardous disasters in metropolitan areas, which causes growing risk on people’s lives, infrastructure and environment. Egypt witnessed an unprecedent extreme rainfall event in 2020 that caused more than four hundred injuries and major damage in properties and infrastructures affecting the economic and social aspects adversely. This was not the first extreme rainfall event causing catastrophic implications, over the past 5 years, New Cairo have been experiencing intense rainfall events almost every year that put the community in jeopardy. This research intends to investigate the main drivers prompting urban flash floods in New …

A Comprehensive Evaluation Of Wastewater Grit Characteristics And Its Application In The Design Of A Facility-Specific Grit Removal Solution, Tetiana Kolsovska

Theses and Dissertations

Tailored solutions for wastewater treatment plants (WWTPs) are becoming more prevalent for optimization of treatment process, based on the unique quality of the influent received by each facility. In-depth evaluation of the influent properties is necessary for design of the most appropriate treatment system. In this study, wastewater grit was evaluated in terms of its quantity, particle size distribution, total organic carbon (TOC) content, including fats, oils, and grease (FOG), and settling velocity of the particles, over the course of one year at the headworks, collection network, and through the treatment stages of the Atlantic County Utilities Authority (ACUA) WWTP, …

Optimization Of A Smart Sensor Wearable Knee Sleeve For Measuring Skin Strain To Determine Joint Biomechanics, David Steven Wood

Theses and Dissertations

This work addresses three objectives related to the design and modeling of an instrumented knee sleeve and its high deflection strain gauges for at-home knee rehabilitation. First, a multi-objective Bayesian approach was developed to economically optimize a high deflection strain gauge's mechanical and electrical behavior. Four objective functions were simultaneously optimized with two design variables in seven iterations; 90% faster than a grid search approach. The presented algorithm adjusts variables in the manufacturing process of high deflection strain gauges and produces a sensor with optimized properties for a predetermined purpose. Second, an algorithm was created to accurately approximate the dynamic …

Advanced Materials For Skin Regeneration, Ingrid Safina

Theses and Dissertations

Massive skin loss, over 20% of the total body surface area, is challenging to heal (Rowan et al. 2015). Ideally, autologous skin grafts have the ability to support complete skin reconstruction. However, skin grafting faces major limitations, such as shortage of donor sites and secondary injury. Alternatively, advanced materials can be used to produce skin constructs that could potentially serve as skin substitutes (Stanton and Billmire 2002). Herein, we used two polymeric materials: graphene and polyurethane (PU) to produce films that support skin cells in their growth and maturation. The surface properties of these materials were modified to enhance their …

Algorithms For Rapid Trip Detection In Human Walking Using Inertial Sensors, Chadi Ellouzi

Theses and Dissertations

Trips and falls are one of the most common causes for injuries among elderly. The existing trip-and-falls studies primarily focus on the proactive fall prevention approaches, while active prevention strategies remain largely unexplored. This thesis aims to provide first steps towards active trip-and-fall prevention by developing various algorithms capable of detecting trip in human walking faster than the human voluntary reactions (~200 ms). The measurements of human kinematics are used as the inputs in the algorithms. The proposed algorithms include three threshold-based detection methods, an optimized elastic time-series alignment tool called dynamic time warping (DTW) that overcomes problems of time …

Flood Warning: A Generalized Approach To Forecast The Impacts Of Flooding Events Using Arcgis Pro, Qgis, And Python, Robert Evan Smith

Theses and Dissertations

Floods are the most common global natural disaster, and 1 billion people live in floodplains worldwide adding to the impactful damage that inundation causes. Disaster managers strive to mitigate damages to their communities but need to know what the impact of a potential flood may be. GEOGloWS ECMWF Streamflow Services estimates forecasted streamflow around the world. These forecasted streamflow's can be used to create predicted flood extent maps using Height Above Nearest Drainage (HAND) or Sedimentation and River Hydraulics - Two Dimension (SRH-2D). Another method to obtain a flood map is using Setinel-1 satellite Synthetic Aperture Radar (SAR) imagery. Flood …

Single Event Transient Sensitivity Measurement And Worst-Case Test Vector Exploration For Asic Devices Exposed To Space Single Event Environment, Mohamed Wael

Theses and Dissertations

Space radiation and nuclear reactors produce single event effects (SEE) in electronic circuits and impact their performance. The SEE phenomena cause circuits and electronic devices to fail by producing faulty results. Therefore, today’s circuit’s reliability is a significant concern for all circuit designers.

This thesis suggests a new automated flow to measure the single-event-transient (SET) effects in combinational circuits in application-specific integrated circuits (ASIC) while reaching full fault coverage. The developed flow characterizes the whole circuit nodes by identifying the most sensitive paths to the propagated SET pulses from the node under test to an observable primary output, causing single …

Multi-Objective Optimization On Dimensional Accuracy, Edge And Surface Quality Of 3d-Printed Parts By Fused Deposition Modelling, Islam Hamdy Salem

Theses and Dissertations

Fused Deposition Modelling (FDM) is one of most common additive manufacturing (AM) techniques used in manufacturing field. It has been increasingly used because of its low cost and simplicity. Although FDM can save time through eliminating pre-processing tooling-up to produce the end-user product, still a better final product quality, like mechanical properties, dimensional accuracy and surface finish, is needed. This thesis addresses the maximization of involved printing parameters in one reliable model. Hence, a wider investigation is conducted in this research via experimental work in order to obtain a comprehensive model that involves and relates more parameters in a single …

Mechanical Properties Of Concrete With 100 Percent Coarse Recycled Concrete Aggregate (Rca), Mohsen H. Motlagh

Theses and Dissertations

Recycled concrete aggregate (RCA) is a crushed concrete with the original aggregates' features and old mortar adhered to the original aggregate which makes it necessary to know the mechanical properties of the RCA. The objectives of this thesis are (a) to characterize RCA from different sources and of different proportions, (b) to measure the mechanical properties of concrete made with 100% RCA as coarse aggregates, and (c) to evaluate how the RCA properties affect the properties of new concrete. The study uses RCA with three types of original aggregates (limestone, dolomite, and granite) in two water-to-cement ratios 0.48 and 0.38 …

Fundamentally Based Investigation And Mathematical Modeling Of The Delay Observed In The Early Stages Of E-Coat Deposition, Fardin Padash

Theses and Dissertations

The objective of this work is to enhance the understanding of the delay observed in the early stages of E-coat deposition. E-coat deposition has been widely used by industries such as the automotive industry to form the primary protective coating against corrosion. Currently, models that are used to find the best conditions under which the desired coating coverage for the entire auto body can be achieved do not accurately predict the coating coverage in recessed areas. The accuracy of large-scale models can be improved by enhancing our understanding of the mechanisms responsible for the observed delay. To accomplish this, experiments …

Durability Properties Of Concrete With 100 Percent Coarse Recycled Concrete Aggregates, Tasnia Tarannum Khan

Theses and Dissertations

The supplies of concrete aggregates from natural sources are rapidly reducing. Recycled concrete aggregates (RCA) are produced by crushing the concrete obtained from demolished concrete structures. The purpose of this study is to determine the durability properties of concrete with 100% recycled concrete coarse aggregates and relate the durability of such concrete to the physical, mechanical, and durability properties of RCA and the RCA parent concrete. The correlations of several properties are determined by developing model equations to predict RCA properties. The parent concrete is crushed and graded at two nominal maximum sizes, 1" and 0.75", to determine the RCA …