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Title: INFORMAL AREAS UPGRADING STRATEGIES: THE CASE OF ADEN CITY-YEMEN
Creator: Ba Tis, Ahmed Abdullah Obaid
Date: 2022
Description: Informal areas are global problems that pose a threat to the urban environment and their consequences prompted urgently to search for...
Show moreInformal areas are global problems that pose a threat to the urban environment and their consequences prompted urgently to search for solutions and methods to address these problems and limit their effects. This thesis examines the issue of informal areas in Yemen. Informal areas are houses built on illegal public or private real estate. In Yemen, these illegal areas began as a relatively new phenomenon and since then have grown at an extremely rapid rate. Increasing rates of urbanization, poverty, and unemployment have led to the rapid rise of slums and informal housing in Yemen. The UN-Habitat database of global urban indicators estimates that 60% of Yemen's urban population lives in informal settlements. The cities most affected by the rapid growth of informal settlements include Taiz, Al Hudaydah, Sana'a, and Aden. The Yemeni government has done little to address the growth of informal areas. However, there was growing concern about this issue, and governmental and non-state actors alike began to consider new approaches to urban policy development and implementation. The importance of the thesis is that it will limit the spread of slums in Aden in the future, and it will also be a good starting point for further research and studies on the issue of developing the problem of informal areas in Yemen. There are many ways to deal with the problem of informal areas, including demolition and resettlement, and development upgrading and each method differs according to the region’s conditions, whether the urban, social economic, location of the area. This study focuses on urban upgrading to clarify its concepts, types and strategies, because it has become one of the most appropriate ways to deal with informal areas and to reach a sustainable urban environment. The thesis aims to find solutions for informal areas in Yemen and limit their growth in the future by preparing a new strategy for dealing with informal areas, in light of the experiences of other countries, and in line with the reality of Yemen.
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Title: Establishing Bisphenol A Degradation and Enhancing Microbial Fuel Cell Performance by Biofilm Optimization of Shewanella Oneidensis MR1
Creator: Zhou, Jiacheng
Date: 2023
Description: Bisphenol A (BPA) has been widely used as a plasticizer in the production of synthetic polymers, such as those used in food storage containers...
Show moreBisphenol A (BPA) has been widely used as a plasticizer in the production of synthetic polymers, such as those used in food storage containers and bottles. However, BPA interferes with endocrine systems, causing carcinogenicity, immunotoxicity, and embryotoxicity. Biological water treatment processes scarcely remove BPA, owing to the poor BPA degradability and efficiency of the applied microorganisms. Shewanella oneidensis has been studied and used for the biodegradation process in wastewater treatment because of its excellent extracellular electron transfer properties. In this work, we engineered S. oneidensis MR1 to enable BPA degradation by producing ferredoxin (Fdbisd) and cytochrome P450 (P450bisd) originating from Sphingomonas bisphenolicum AO1. The engineered S. oneidensis exhibited a higher BPA degradation efficiency than that of Escherichia coli producing the same enzymes. The endogenous ferredoxin and ferredoxin reductase of S. oneidensis participated in BPA degradation, and overexpression of mtrC, omcA, and So0521, which encode S. oneidensis cytochromes, decreased BPA. We developed BPA-degrading S. oneidensis biofilms. We measured these optimized BPA-degrading S. oneidensis biofilm in a single chamber microbial fuel cell formed on different carbon electrodes by morphology. Cyclic voltammetry and electrochemical impedance spectroscopy were measured to analyze the biofilm-electrode performance. The biofilm colonization was also measured by confocal laser scanning microscope and scanning electron microscope. And the developed microbial fuel cell was used to degrade BPA and the biofilm developed on different type of carbon anodes was identified. This study provides insights into biocatalyst utilization for the biological degradation of toxic organic compounds.
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Title: Carrier phase multipath characterization and frequency-domain bounding
Creator: Benz, Chloe
Date: 2022
Description: Safely relying on Global Navigation Satellite Systems (GNSS) measurements for position estimation using multi-sensor navigation algorithms,...
Show moreSafely relying on Global Navigation Satellite Systems (GNSS) measurements for position estimation using multi-sensor navigation algorithms, especially in critical phases of flight – such as takeoff or landing – requires precise knowledge of the errors affecting position estimates and their extrema values at any time. This work investigates a method for characterization and power-spectral density (PSD) bounding of GNSS carrier phase multipath error intended for use in sensor fusion for aircraft navigation. In this dissertation, two methods of GNSS carrier phase multipath characterization are explored: single frequency dual antenna (DA) and single antenna dual frequency (DF). However, since not all aircraft are equipped with multiple GNSS antennas, because the DA method entails a meticulous tracking of the lever arm between the two antennas, and as multipath seen by two antennas in a short baseline configuration may cancel out, the DF method is preferred and is the main emphasis of this work. By subtracting carrier phase measurements collected by a receiver overtwo distinct frequencies, a composite measurement containing ionospheric delay and carrier phase multipath is obtained. The ionospheric delay has slower dynamics than multipath, so it is removed using a high pass filter. The filter cutoff frequency is carefully picked based on a study of ionospheric delay dynamics. The DF method is validated on a rooftop GPS carrier phase dataset, and finally, directions and considerations for its ultimate intended use on airborne collected GNSS carrier phase data are provided.
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Title: Cities on the Move: Envisioning Cityscape in the Autonomous Vehicle Era
Creator: Lee, Hyo Eun
Date: 2023
Description: As cities have developed in response to a rapidly changing environment since the industrial revolution, a variety of circumstances and issues...
Show moreAs cities have developed in response to a rapidly changing environment since the industrial revolution, a variety of circumstances and issues have arisen. In cities, technological development and the rise of private automobiles have been related to urban sprawl, traffic congestion, environmental degradation, and mobility inequalities. Currently, autonomous vehicles are bringing a paradigm shift in mobility as technological innovations accompany the fourth industrial revolution. As cities undergo renewal through new mobility, recent developments in driverless technologies should be considered for their long-term impact on the built environment. The purpose of this thesis is to propose a design, along with a set of scenarios, for a transportation hub in the era of autonomous vehicles to address today's complex mobility requirements. Through bringing together existing case studies, research on autonomous vehicles, and drawing conclusions regarding the relationship between mobility and urban landscapes, this thesis explores how autonomous vehicles will affect the future built environment in a set of timelines. Considering the future transportation hub will require programs and infrastructure to support autonomous vehicles, this thesis also provides a vision of the future of transportation modes and how they interact. Finally, a transportation hub design model and an automation city model for the AV era will be proposed.
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Title: DESIGN FOR COMFORT: DESIGN BUILDING ENVELOPE TO IMPROVE THERMAL COMFORT FOR RESIDENTIAL BUILDINGS IN AL-MUKALA, YEMEN
Creator: Bakarmom, Aamena Mubarak Saeed
Date: 2021
Description: This thesis is about the research into the design of building envelopes to reduce energy consumption and moderate thermal performance of the...
Show moreThis thesis is about the research into the design of building envelopes to reduce energy consumption and moderate thermal performance of the residential buildings in Yemen, which is in an arid climate. A suitable building envelope is important because of the building occupants’ thermal comfort. The most important question is how architects could implement high-performance envelope technologies in their designs, especially in residential buildings. These technologies have some basic principles which are applied differently from one region to another. One of the most promising strategies applied to house envelopes in a hot-dry climate is the passive cooling design. This thesis reviews the results of other research in the same region that discuss proper parameters of building envelopes such as form, width, climate, walls, materials, and windows design. Passive cooling strategies will be the key to providing potential design building envelopes that provide thermal comfort and reduce energy use. This study applies the natural ventilation principle (single-sided, cross- or stack ventilation), thermal mass, and shaded devices. The research methods were to collect data and create quantitative models to analyze the data. From this analysis, I suggest specific architecture guidelines for design in residential buildings which could improve comfort in indoor spaces for occupants.
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Title: CABLE MODELING AND FAULTSTUDY FOR THE lIT PERFECT POWER SYSTEM
Creator: Gupta, Abhinav
Date: 2011-05-02, 2011-05
Description: IIT has taken part in the smart grid initiative by converting the existing radial distribution network into a looped network to increase the...
Show moreIIT has taken part in the smart grid initiative by converting the existing radial distribution network into a looped network to increase the reliability of the system as part of the ’Perfect Power’ project. A total of 7 loops have been planned with the help of fast fault clearing relays (’Vista Switches’). As part of the project, the cable is modeled using the various impedance calculators and was also done using the PSCADrsoftware. With the obtained impedance values from the impedance calculators, the cables were analyzed under various outage/contingency cases. They include base case power flows of the old IIT distribution network as well as the Loop 3 of the perfect power project implemented and open circuit analysis and short circuit analysis of the Loop 3 alone. Also, with the help of the fault current values from the short circuit study we can analysis the relay settings and operations and review the later for the newly installed relays. And finally, the cable fault classifier was designed using the Artificial Neural Network (ANN) method in MATLABrand PSCADrsoftware. Here we model the cable using the impedance calculated and collect the voltage and current samples from the two ends of the cable which is given as input to the ANN classifier and the same is tested for accuracy.
M.S. in Electrical Engineering, May 2011
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Title: WIND MICRO-CLIMATE CONFORMATION IN HOT DRY CITIES; RIYADH
Creator: Alhawsah, Saeed Idris
Date: 2019
Description: Recently, the transformation in urban development in Saudi Arabia has caused abrupt and sporadic change to its desert climate. Careful...
Show moreRecently, the transformation in urban development in Saudi Arabia has caused abrupt and sporadic change to its desert climate. Careful environmental consideration of vernacular architecture practices is lost by the vast modernization. The significant changes of modernization contain desertification, sand rapping due to massive urban construction, and urban heat islands, all that has created a severe issue with sandstorms. Saudi’s modernization changed sandstorms phenomena from its seasonal occasions to a frequent rapid increase as a result of the urban inability to maintain its naturally mild and soothing condition. All the global incidents from the natural refugees in Gobi Desert, China, to the 1930s U.S. dustbowl are evident to the urban environmental disturbance. This research is an environmental investigation to reduce the sandstorm effects in Saudi Arabia through designing multiple territorial landscape interventions to filter out the sandstorms and trap its sediments to avoid reoccurring sandstorms.
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Title: BEYOND THE GREEN IDEAL - RESHAPING CHICAGO SOUTH LOOP
Creator: Hoeflich Brune, Vivian Eliese
Date: 2015, 2015-12
Description: Analyzing the growing metropolis, this research questions the relation between the built and open environment on its process of densification....
Show moreAnalyzing the growing metropolis, this research questions the relation between the built and open environment on its process of densification. Urban areas depend upon landscape and broader natural areas to be sustained. The current system, in which landscape is the center of extraction and production and cities centers of consumption, has an unhealthy one-direction flow of energy and materials. By linking the urban landscape, buildings, and parks, a new ecological infrastructure breaks this traditional system and can become the own natural living system of the urban environment. By preserving existing open spaces in the city and introducing new ones, this thesis explores how to increase urban density and, at the same time, create new social-ecological associations. Movement from outside city to its center resulted in urban population increase and recently is transforming the near South region of Chicago. Therefore, this study explores the introduction of a set of open spaces for collective experiences in two scales. First, is investigated the impact of inserting a new landscape infrastructure on the existing urban fabric of Chicago South Loop neighborhood. Through the study of the current site, the identification of underutilized or public lots set a framework for intervention, adding available spots into a network of open spaces that support diverse programs for the area. Rethinking the traditional urban block consists the second studied topic, exploring the relation of built and open spaces on a smaller scale. Not only the continuity to the open space infrastructure is essential for the project but also the creation of a new urban lifestyle inside one city block and its nearby areas. Being on a strategic site connected to the public transportation system and Museum Campus, the proposal works as a condensed program center. Both local neighborhood and a broader public of visitors and tourists are attended, combining a multiplicity of programs, users, built and open space typologies.
M.S. in Architecture, December 2015
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Title: THERMAL AND MECHANICAL ANALYSIS OF ELECTRON BEAM ADDITIVE MANUFACTURED TI-6AL-4V BUILD PLATE
Creator: Cao, Jun
Date: 2017, 2017-07
Description: Electron Beam Additive Manufacturing (EBAM), used to fabricate net or nearnet- shaped components based on a sliced CAD model, offers a...
Show moreElectron Beam Additive Manufacturing (EBAM), used to fabricate net or nearnet- shaped components based on a sliced CAD model, offers a potential alternative solution for the processing of titanium components, especially for large parts. However, the components fabricated using EBAM exhibit significant difficulties in quality control and quality assurance due to lack of knowledge of thermo-mechanical-metallurgical relationship. In this work, the thermo-mechanical behavior of wire-feed EBAM for largescale Ti-6Al-4V build plates has been investigated computationally and experimentally, with special attention to the distortion and residual stress, as well as the microstructural evolution. A 3D transient fully coupled thermo-mechanical finite element (FE) model was built, calibrated, and rigorously validated. To ensure the accuracy of the model, the bulk residual strain distribution was measured using neutron diffraction (ND), and the numerically simulated thermal profiles were physically simulated using a Gleeble® 3500, in addition to the conventional model validation methods. Good agreement was found between the simulation results and experimental measurements. A series of simulations were performed to determine the optimum process conditions. The simulation results indicated that preheating, increasing deposition power and scan rate, and decreasing interval cooling time effectively mitigates the distortion and residual stress. For EBAM Ti-6Al-4V build plates, increasing the energy input and reducing the heat loss renders smaller temperature difference and thermal expansion mismatch, consequently, leading to a lower level of distortion and residual stress. The deposited cladding was characterized by large columnar grains growing across layers, a bottom region with repeated macroscopic bands and a top region without these bands. The band structure exhibits mostly colony α. A fine basket-weave structure is observed above the band structure, and a coarse basket-weave structure is observed below the band structure. The simulated thermal profiles were used to understand the observed microstructure. It was found that the microstructure variation in the cladding of EBAM Ti-6Al-4V build plates is strongly dependent on the peak temperature within the (α+β) phase region, and heating rate and cooling rate have insignificant effects on it. The non-equilibrium solid-solid phase transformation of Ti-6Al-4V under continuous heating/cooling were experimentally investigated. The kinetics of phase transformation was quantitively studied and modeled using a non-isothermal JMAK (Johnson-Mehl-Avrami-Kolmorgorov) model, with the activation energy QA=123.9 kJ/mole, JMAK exponent n=1.8, and the calculated ln (k0) varied between 9.15 to 10.6 for different heating rate.
Ph.D. in Materials Science and Engineering, July 2017
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Title: STRUCTURE-PROPERTY RELATIONSHIPS IN ANION EXCHANGE MEMBRANES FOR ELECTROCHEMICAL ENERGY CONVERSION AND STORAGE
Creator: Arges, Christopher George
Date: 2013, 2013-12
Description: Polymer electrolyte membrane (PEM) fuel cells are promising candidates for powering automotive vehicles, but their advancement has been...
Show morePolymer electrolyte membrane (PEM) fuel cells are promising candidates for powering automotive vehicles, but their advancement has been hindered by the costs associated with their platinum-based electrocatalysts. One strategy to resolve this problem is to replace the conventional acidic PEM with an alkaline anion exchange membrane (AEM) because fuel cells operated in alkaline media do not require platinum group metal catalysts. A significant challenge to realizing this concept is to design and implement an AEM that is chemically robust under alkaline conditions and that facilitates high ionic conductivity. This dissertation presents a scientific approach to address the aforementioned problems through investigation of alternative cations, beyond quaternary trimethylammonium, to understand what chemical features influence ion conductivity and alkaline stability. It was postulated that selecting cations with larger free base conjugate pKA values (i.e., greater basicity) would yield improved AEM alkaline stability and ionic conductivity. The pKA value accounts for the steric hindrance, inductive, and resonance features of an organic cation and these features influence a cation’s interaction with hydroxide. Udel® polysulfone (PSF) and poly(2,6-dimethyl 1,4-phenylene) oxide (PPO) were selected as the model polymer backbones because they can be tailored with different cation groups. The types of cations assessed were of the quaternary ammonium and phosphonium types and 1-methylimidazolium. The prepared AEMs demonstrated a direct correlation between the cation’s free base conjugate pKA and anion conductivity for most cations assessed. Alkaline stability was assessed through multi-dimensional NMR to determine the degradation products in AEMs. NMR confirmed that the cation groups x xxii degraded through fundamentally different degradation mechanisms dependent upon their chemical make-up. Because the degradation mechanisms were different, the rate of degradation of the cation groups did not demonstrate a correlation to the cation’s free base conjugate pKA. If the cations did proceed through the same degradation mechanism, then a correlation was observed. Additionally, it was discovered that the cation groups in PSF and PPO triggered polymer backbone degradation in alkaline despite the resiliency of both these pristine polymers in alkaline solutions. The AEMs prepared were successfully demonstrated in several electrochemical energy storage and conversion technologies (including alkaline fuel cell, alkaline water electrolyzer, and the all-vanadium redox flow battery).
PH.D in Chemical Engineering, December 2013
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Title: SECURE DATA SERVICE OUTSOURCING IN CLOUD COMPUTING
Creator: Wang, Cong
Date: 2012-04-22, 2012-07
Description: Cloud computing economically enables a fundamental paradigm of data service outsourcing, which provides lower up-front capital costs and less...
Show moreCloud computing economically enables a fundamental paradigm of data service outsourcing, which provides lower up-front capital costs and less hands-on management. However, outsourcing data services to the commercial public cloud deprives customers' control over the systems that manage their data, raising security and privacy as the primary obstacles to the adoption of the cloud. To address these challenges, in this dissertation we explore the problem of secure and privacy-assured data service outsourcing in cloud computing. We aim at deploying the most fundamental data services including data storage, search, and sharing on the commercial public cloud, with built-in security and privacy assurance as well as high level service performance, usability, and scalability. Our contributions are as follows: Firstly, we focus on privacy-preserving secure cloud storage auditing to maintain strong storage correctness guarantee, given the di culty that data les are no longer locally possessed by data owners. We rst develop a random-masking sampling approach to allow a third party auditor to perform on-demand privacy-preserving storage correctness auditing on behalf of data owners, without violating owners' data privacy. For storage correctness assurance with data dynamics, we further investigate a novel sequence-enforced Merkle Hash Tree and manipulate it with the random sampling approach to support fully dynamic data operations. Secondly, we focus on privacy-assured and e ective cloud data search services with strong privacy-assurance, while enjoying high service-level performance inherently demanded by the large number of data users and huge amount data les. We rst investigate a widely applicable fuzzy/similarity keyword search problem, and develop a brand new symbol-based trie-traverse searching approach, where transformed fuzzy keywords extracted from data les are stored using a multi-way tree structure, while protecting keyword privacy. To enable search result relevance ranking, we further investigate secure ranked search, which facilitates e cient server-side result ranking without leaking any keyword related information. Thirdly, we study how to enable scalable and owner-controlled cloud data sharing services, given the challenge that data no longer resides on owners' trusted domain. We rst associate data with a set of meaningful attributes, use logical composition of attributes to re ect ne-grained data access, and enforce owner's control via attribute-based encryption. For the inherent scalability requirement of cloud system, we further leverage the cloud as a mediated proxy, to which data owners can delegate most cumbersome data/user management workload, without a ecting the underlying data con dentiality.
Ph.D. in Electrical Engineering, July 2012
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Title: ANALYSIS OF ZENO STABILITY IN HYBRID SYSTEMS USING SUM-OF-SQUARES PROGRAMMING
Creator: Murti, Chaitanya
Date: 2012-12-14, 2012-12
Description: Hybrid dynamical systems are systems that combine continuous dynamics with discrete transitions. Such systems can exhibit many unique...
Show moreHybrid dynamical systems are systems that combine continuous dynamics with discrete transitions. Such systems can exhibit many unique phenomena, such as Zeno behavior. Zeno behavior is the occurrence of infinite discrete transitions in finite time. This phenomenon has been likened to a form of finite-time asymptotic stability, wherein trajectories converge asymptotically to compact sets in finite time whilst undergoing infinite transitions. Corresponding Lyapunov theorems have been developed. The main objective of our research was to develop computational techniques to determine whether or not a given hybrid system exhibits this Zeno phenomenon. In this thesis, we propose a method to algorithmically construct Lyapunov functions to prove Zeno stability of compact sets in hybrid systems. We use sum-of-squares programming to construct Lyapunov functions that allow us to prove Zeno stability of compact sets for hybrid systems with polynomial vector fields. Examples illustrating the use of the proposed technique are also provided. Finally, we provide a method using sum-of-squares programming to show Zeno stability of compact sets for systems with parametric uncertainties in the vector field, guard sets and domains, and transition maps. We then discuss potential applications of the proposed methods, along with examples.
M.S. in Electrical Engineering, December 2012
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Title: EXECUTIVE FUNCTION AND DEPRESSIVE SYMPTOMS IN PATIENTS WITH ISCHEMIC STROKE
Creator: Marola, Jennifer
Date: 2013, 2013-07
Description: Previous research has demonstrated impairment following stroke, including depressive symptoms (Herrmann et al., 2011; O'Brien et al., 2003;...
Show morePrevious research has demonstrated impairment following stroke, including depressive symptoms (Herrmann et al., 2011; O'Brien et al., 2003; Robinson, 2006; Robinson & Spalletta, 2010; Teper & O'Brien, 2008) and cognitive impairment, particularly in executive function (Canning, Leach, Stuss, Ngo, & Black, 2004; Carew, Lamar, Cloud, Grossman, & Libon, 1997; Garrett et al., 2004; Kertesz & Clydesdale, 1994; Lafosse et al., 1997; Madureira, Guerreiro, & Ferro, 2001; Padovani et al., 1995; Su, Lin, Kwan, & Guo, 2008). Current research is limited by the use of primarily patients in the hospital with multiple types of stroke and physical impairment. Additionally, a conceptualization of executive function by Stuss and colleagues (Stuss, Shallice, Alexander, & Picton, 1995) has not been thoroughly investigated utilizing factor analytic techniques. The current study attempted to expand research on executive function and depressive symptoms in individuals with ischemic stroke. This study examined performance on measures of executive function, memory, language, and visuospatial ability, along with measurement of depressive symptoms in participants with ischemic stroke and healthy matched control participants. Results revealed that participants with stroke performed significantly worse in all cognitive domains than control participants. More specifically, in participants with stroke, executive function was more impaired than memory, language, and visuospatial ability. A regression analysis did not find that depressive symptoms accounted for additional variance in executive function above x demographic factors. Two and three factor models of executive function were not supported; the data more closely resembled a one factor model of executive function.
PH.D in Psychology, July 2013
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Title: A STRUCTURAL ANALYSIS FRAMEWORK FOR CONCRETE FACED ROCKFILL DAMS
Creator: Quiroz, Juan E.
Date: 2013, 2013-12
Description: Concrete Faced Rockfill Dams (CFRD’s) are commonly built around the world. As energy demands soar and construction methods evolve, the...
Show moreConcrete Faced Rockfill Dams (CFRD’s) are commonly built around the world. As energy demands soar and construction methods evolve, the interest for construction of CFRD’s with larger heights has increased tremendously. However, because of construction of higher CFRD’s, some dams have experienced considerable fractures at the concrete faces. Well known cases include Campos Novos (Brazil), Barra Grande (Brazil), and Mohale (South Africa), where in some instances these cracks have led to dewatering of the reservoir to allow for the concrete slabs repairs. The development of these fractures may be attributed to the highly deformable rockfill body. In general, the state-of-the-art design of CFRD’s is mostly based on common practice rather than rigorous analysis procedures. And as such, cracking problems because of deformability of the rockfill may not be properly predicted unless a detailed analysis is performed. In this work, a new framework for analysis of CFRD’s is developed that is capable of predicting the possible concrete-facing failure. As a part of this framework, a comprehensive non-linear finite element analysis (FEA) scheme is developed to model the construction sequence, the contact interaction between the concrete facing and the rockfill body, and the impounding of the reservoir. As a case study, using the developed framework, the Kárahnjúkar CFRD (Iceland, 198m height) is analyzed, the results are validated by the field measurements, and mitigation measures suggestions are provided. This methodology, based on the results of the investigation, provides guidelines and establishes a framework for analysis of CFRD’s that can be used for design purposes.. Keywords: CFRD, Concrete Faced, Rockfill, Dam, Finite Element Analysis.
PH.D in Structural Engineering, December 2013
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Title: A BAYESIAN UPDATING APPROACH IN STRUCTURAL HEALTH MONITORING FOR DAMAGE DETECTION AND ASSESSMENT
Creator: Dirbaz, Mojtaba
Date: 2013, 2013-05
Description: The primary goal of Bridge Condition Assessment (BCA) is to determine the condition of a bridge to prevent any catastrophic failure as well as...
Show moreThe primary goal of Bridge Condition Assessment (BCA) is to determine the condition of a bridge to prevent any catastrophic failure as well as to enhance the structure’s safety and serviceability. The structural health and condition of in-service bridges is generally assessed through visual inspections and nondestructive testing and evaluation (NDT/NDE) methods conducted on a pre-set schedule. However, the ratings obtained from current visual inspections on a bridge are subjective, and do not include the uncertainty inherent in the results. Moreover, the condition ratings are often based on independent inspections and do not take into account the dependence of results on previous conditions of a bridge and prior condition ratings compiled for it. Furthermore, there is also a certain level of uncertainty involved in relating subjective ratings to the actual condition of the bridge. This study is aimed at conducting a research on damage detection of existing bridges utilizing available information on their structural conditions. The first part of the research focuses on a new method for assessing the condition of a bridge based on subjective ratings obtained for the bridge. This method will hereafter be referred to as Bayesian Bridge Condition Assessment (BBCA). BBCA consists of three parts: (1) identification of condition states for structural components, (2) determination of a Damage Index (DI), a parameter to describe the extent of damage to a structural component, and (3) determination of an Updated Damage Index (UDI) using Bayesian updating approach. UDI offers an enhanced measure that incorporates not only the relation between subjective rating and the structure’s health condition, but also the significance of new information as it becomes available. The basic assumptions and x general formulations of the Bayesian updating method is presented. Numerical illustrations are provided to demonstrate the applicability of the method to highway bridges. It is shown that the method described in this study is especially applicable to bridges for which visual inspection data are compiled on a periodic basis. One of the methodologies for damage detection and assessment is to use sensor data for identifying the modal characteristics of the structure. The second part of this research focuses on improving upon damage detection methods using sensor and/or modal data. Thus a new method for damage detection and assessment of structures using finite element analysis, and modal data is developed and demonstrated. This method will hereafter be referred to as Bayesian Structural Condition Assessment (BSCA). Using this method, (1) a Finite Element (FE) design model of the structure (undamaged) is constructed; (2) the measured modal data is updated using a Bayesian framework; and (3) the FE model of existing structure (with possibility of damage) is obtained using updated modal data based on an iterative optimization method that is used in estimating the stiffness of the damaged structure. Using these steps, the location and extent of any possible damage is then determined based on the difference between a structural element stiffness for the “as built condition” and “damaged condition.” Several numerical illustrations are presented to demonstrate the capability of the method to detect the location and extent of the damage. This method has been applied to a structural health monitoring benchmark problem; and it has been shown that it can identify the location and extent of damage with more accuracy than most other existing models. Keywords: Bayesian Updating, Condition Assessment of Structures, Modal Data, Visual Inspections, Finite Element Model, Bridges
PH.D in Structural Engineering, May 2013
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Title: ASSESSMENT OF THE VALIDITY AND RELIABILITY OF THE ROMANTIC RELATIONAL INVENTORY: A MEASURE OF THE DEGREE OF ADAPTIVENENESS WITHIN THE DECLARATIVE ASPECTS OF ROMANTIC RELATIONAL SCHEMA
Creator: Grix, Bethany
Date: 2011-11-28, 2011-12
Description: A measure was developed to quantify an individual’s romantic relational schema, after conducting a literature review of the variables to which...
Show moreA measure was developed to quantify an individual’s romantic relational schema, after conducting a literature review of the variables to which it was related. The measure was designed to assess comprehensively the dimensions and degree of adaptiveness within this important construct. This new measure, the Romanic Relational Inventory (RRI), was subject to psychometric analyses and a final 93 item measure was derived from the factor analyses on 104 original items. The RRI was shown to be a reliable and valid measure of the descriptive components of romantic relational schema as demonstrated by the measures of external validity and reliability analyses. A series of Experimental Factor Analyses suggested that the initial single factor hypothesized domains were supported (i.e., Relationship Components; Expectations of Relationship Behaviors; Partner Components, which included two sub-domains: Partner Traits and the Congruence of Self with Other; and Global Perceptions of Romantic Relationships). The results suggest that the RRI may be a reliable and valid multidimensional measure, with distinct yet overlapping dimensions or sub-constructs.
M.S. in Psychology, December 2011
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Title: NUTRIENT REMOVAL FROM SECONDARY EFFLUENTS USING REACTIVE FILTRATION
Creator: Bhupal, Gurmanpreet Singh
Date: 2015, 2015-07
Description: Simultaneous removal of dominant forms of nitrogen and phosphorous present in secondary effluents was studied with reactive filtration as the...
Show moreSimultaneous removal of dominant forms of nitrogen and phosphorous present in secondary effluents was studied with reactive filtration as the treatment method. The selected media for filter bed included Granular Ferric Hydroxide (GFH), Calcite (C), Silica Sand (S), and Activated Alumina (A). The focus was to evaluate the performances of media blends GFH-C-S and A-C-S for removal of sRP and sNO3-N in lab scale batch and column experiments using secondary effluents provided by Calumet Water Reclamation Plant. The media blends performed better for sRP removal than sNO3-N removal with A-C-S being outperformed by GFH-C-S in batch experiments, and hence was not used for column experiments. The removal kinetic study using GFH-C-S showed 100% sRP removal rate and 45% NO3-N removal rate for an optimal contact time of 2 minutes, with latter showing gradual desorption after initial instant adsorption. The optimal adsorbent dosage for sRP was found to be 15g (1:1:1) whereas for NO3-N, the removal rates increased with an increase in adsorbent dosage. Column experiments with GFH-C-S gave an adsorption capacity of 1.8 mg/g for an equilibrium concentration of 0.1 mg P/L with breakthrough occurring after a throughput of 603 bed volumes.
M.S. in Environmental Engineering, July 2015
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Title: SOLIDS ROLE IN TERTIARY CHEMICAL PHOSPHORUS REMOVAL BY ALUM
Creator: Maher, Chris
Date: 2013, 2013-12
Description: Chemical phosphorus (P) removal is commonly implemented in wastewater treatment to remove P to very low levels (
Show moreChemical phosphorus (P) removal is commonly implemented in wastewater treatment to remove P to very low levels (<0.1 mg P/L). The dose of precipitant (Al or Fe) needed is several times the stoichiometric dose in order to achieve a filtered effluent level of < 30 μg TP/L. The mechanistic basis for P removal using chemical precipitant addition is generally considered to be more than simple precipitation. The role of adsorption and/or complexation in removal of reactive or unreactive phosphorus to the already formed chemical precipitates or complexes has been investigated. Potential operational efficiency gains resulting from age of chemically precipitated solids and the recycle of these solids to the process stream was undertaken at the Iowa Hill Water Reclamation Facility which employs the DensaDeg® process (IDI, Richmond, VA) for tertiary chemical P removal. The effect of solids age was found to be insignificant over the solids retention time of 2 to 8 days, indicating that the solids were unaffected by the aging effects of decreasing porosity and surface acidity, and that the bulk of solids were retained in the clarifier blanket, hence providing no advantage in the removal mechanisms from increased concentration of solids. When solids recycle was redirected from the traditional location of the flocculation reactor to a point just prior to chemical addition in the chemical mixing reactor, lower effluent soluble P concentrations at lower molar doses of aluminum were achieved. At laboratory scale, the “spent” or “waste” chemical sludge showed high capacity and rapid kinetics for P sorption from real wastewater effluents. A number of scenarios were tested and the wide range of parameter values indicate that the sorption reaction is rather specific to the sludge and the process water matrix. x Saturation concentrations were in the range of 8 to 29 mg soluble reactive P/g solids. Higher saturation concentrations were found at higher temperatures. Ambiguous results were obtained for the effect of sludge age on capacity, implying dependence on either aging conditions or sample matrices. In all instances alum sludge produced without a coagulant aid polymer had a much higher capacity for P sorption than polymer based sludge. The reaction reached equilibrium in less than 10 minutes with 50% or greater removal within the first minute. Removal reactions were modeled well by nth order equations with n 3 and by exponential data fitting. Modeled as a sorption process, the pseudo-second order model presented by Ho and McKay in 1999 proved to be an excellent fit. Second order rate constants ranged approximately from 0.1 to 6 (g mg-1 min-1) depending on the P fraction examined, age of sludge, reaction temperature, and presence or absence of coagulant aid polymer in the sludge.
M.S. in in Environmental Engineering, December 2013
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Title: STUDY OF PARALLEL AUTOCATALYTIC REACTIONS IN COUPLED REACTORS
Creator: Hegishte, Swapnil R.
Date: 2012-04-29, 2012-05
Description: The inherent nonlinearity in cubic autocatalytic system has been the reason for its study in various combinations. Parallel cubic...
Show moreThe inherent nonlinearity in cubic autocatalytic system has been the reason for its study in various combinations. Parallel cubic autocatalytic reactions are analogous to the simultaneous consumption of multiple substrates by the same autocatalytic species. Steady state analysis reveals that there can be up to five steady states possible and two of them are always unstable. Individual parameter effect on steady state structure leads to identification of an isola, mushroom and other exotic patterns on equilibrium plot. Stability analysis leads to developing an operating diagram, which also explains the oscillatory behavior with the study of Hopf bifurcation. Concept of coupled isothermal continuous stirred tank reactors enriches the complexity of the system and the steady state behavior. The two reactors are identical in terms of the feed concentrations and the reactor space time. The coupled reactor system can have maximum twenty five steady states at very low interaction rate (R → 0), nine out of which may be stable. The steady state analysis portrays the patterns for transition in number of steady states as R is varied. Appearance of an additional Hopf point confirms the effect of complexity of coupled reactors configuration on stability structure of the system. Numerical simulations exhibit the rich steady state behavior in coupled reactors. Dynamic study for single reactor confirms the possibility of chaos in multistable parameter space. The coupled reactor dynamics focuses on the limit cycle interactions and emergence of chaos due to an added complexity.
M.S. in Chemical Engineering, May 2012
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Title: REAL-TIME ARAIM USING GPS, GLONASS, AND GALILEO
Creator: Cassel, Ryan
Date: 2017, 2017-05
Description: Since the inception of GPS, satellite navigation has been a widely used means of navigation for both military and civilian users on the ground...
Show moreSince the inception of GPS, satellite navigation has been a widely used means of navigation for both military and civilian users on the ground and in the air. GPS is capable of providing highly accurate positioning and timing information to users around the globe. However, for certain applications, providing high-accuracy position estimates is not sufficient. Because satellites are susceptible to faults, the safety, or integrity, of the position estimates is also of concern, especially in civilian aviation where safety is critical. As such, receiver autonomous integrity monitoring (RAIM) can be used in order to detect and potentially exclude these faults and guarantee the safety of the position estimate. RAIM has been capable of supporting horizontal aircraft navigation using GPS for decades and has proven to be a useful tool. Now, as more global navigation satellite systems (GNSS) become available, the potential for advanced RAIM (ARAIM) to support vertical guidance for aircraft using multiple constellations has become an area of great interest. In this work, the ARAIM methodology is discussed, and the procedure is outlined, including protection level calculation, fault detection, and exclusion. The procedure is then implemented in a real-time ARAIM prototype. While GPS and Galileo aim to provide worldwide coverage for vertical guidance by 2020 when Galileo is fully operational, ARAIM performance can be examined at present using the current full-strength GPS and GLONASS constellations. This prototype performs position estimation and ARAIM using measurements from the current GPS, GLONASS, and partial Galileo constellations. ARAIM results in a variety of different GNSS scenarios are examined. Furthermore, this work investigates two methods of improving the computational efficiency of the ARAIM algorithm: satellite selection and fault mode grouping.
M.S. in Mechanical and Aerospace Engineering, May 2017
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