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Title: POSTTRAUMATIC GROWTH AMONG HIV-SEROPOSITIVE ADOLESCENTS AND YOUNG ADULTS
Creator: Niel, Kristin A.
Date: 2016, 2016-12
Description: An estimated 1,218,400 individuals in the United States were living with HIV/AIDS in 2014 (CDC, November 2015). In addition, 9,731 youth...
Show moreAn estimated 1,218,400 individuals in the United States were living with HIV/AIDS in 2014 (CDC, November 2015). In addition, 9,731 youth between the ages of 13 and 24 were newly diagnosed with HIV, with 81% of those diagnoses between ages 20 and 24. African-Americans accounted for 44% of new infections, with young gay and bisexual men accounting for 72% of new infections in all persons between 13 and 24. Research has suggested that a diagnosis of HIV/AIDS can be experienced as a trauma (Kelly et al., 1998; Nightingale, Sher, Mattson, Thilges, & Hansen, 2011). Posttraumatic growth (PTG) is characterized by significant, positive transformations that may occur in response to trauma and has been linked to improved mental and physical health among people living with cancer and adults living with HIV (Barskova & Oesterreich, 2009); however, these relations have not been sufficiently explored among youth living with HIV/AIDS. This study examined 71 HIV-seropositive youth at an urban medical clinic. It was hypothesized that (1) some youth would experience their HIV diagnosis as traumatic; (2) some youth would experience PTG; (3) higher levels of PTG would be associated with better health-related quality of life; (4) PTG would be positively associated with medical regimen adherence, and this relation would be mediated by serostatus disclosure; (5) PTG would be positively associated with physiological health, and this relation would be mediated by serostatus disclosure; and (6) the relation between serostatus disclosure and PTG would be moderated by social support satisfaction. Analyses revealed that 73.2% of participants experienced their diagnosis as traumatic, and 71.8% reported some level of PTG. A positive relation existed between PTG and the Social Relationships Domain of quality of life (β= .32, p < .01). Serostatus disclosure did not act as a mediator for the relations between PTG and adherence or health; however, there was a negative relation between disclosure and appointment attendance (β = -.46, p < .05). Finally, social support satisfaction moderated the relation between disclosure and PTG, such that the relation was stronger in those with average or high support satisfaction than those with lower satisfaction. Clinical and future research implications of these findings are discussed.
Ph.D. in Psychology, December 2016
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Title: ELECTRIC-HYDRAULIC HYBRID ENERGY STORAGE SYSTEM FOR ELECTRIFIED TRANSPORTATION
Creator: Niu, Geng
Date: 2017, 2017-07
Description: Environmental issues and fossil fuel depletion push the evolution of transportation and electrified transportation into the most likely next...
Show moreEnvironmental issues and fossil fuel depletion push the evolution of transportation and electrified transportation into the most likely next generation. However, there are several challenges in electrification with the major concerns involving the energy storage system. A hybrid energy storage system may provide an opportunity to improve the energy storage system of applications in transportation electrification. Hydraulic systems have been a mature technology for a long time and this study proposes a hydraulic add-on for electric vehicles. The high power density of a hydraulic accumulator could absorb high frequency regenerative braking and support battery discharging during acceleration, which will extend the driving range and reduce the current stress of the battery pack. Several models and controls have been created to evaluate hydraulic add-ons in di↵erent applications. The simulation results show a roughly 30% current stress drop and up to 25% energy saving (Wh/km) on average for city buses and delivery trucks over di↵erent driving cycles. A scaled down prototype vehicle with a novel electric hydraulic hybrid powertrain based on a go-kart chassis was built to perform road tests to validate the simulations results.
Ph.D. in Electrical Engineering, July 2017
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Title: REMOVAL OF BACTERIAL CONTAMINANT FROM MODEL SUBSTRATES USING A MICELLAR NANOFLUID FORMULATION
Creator: Shim, Jiyoung
Date: 2017, 2017-05
Description: The oscillatory structural force (OSF) of a micellar film of sodium dodecyl sulfate (SDS) was monitored with atomic force microscope (AFM)...
Show moreThe oscillatory structural force (OSF) of a micellar film of sodium dodecyl sulfate (SDS) was monitored with atomic force microscope (AFM) using an attached glass microsphere against a smooth flat and energy homogenous solid substrate. The force versus distance measurements for the 0.03M and 0.06 M SDS micellar solutions were monitored. The force versus distance had an oscillatory decay profile with a period of oscillation which was the same as the micellar diameter. The number of periodic oscillations increased with an increase in the micellar concentration. The OSF in the SDS micellar film confinement was also proved by a thinning single foam film formed from a micellar solution. It was observed that, due to micellar layering, the film thinned in a multiple regular stepwise manner promoted by the OSF. The results obtained by the AFM and thinning single foam film were used in the application of the OSF to remove bacteria from a model solid substrate. The experimental data for the OSF was complemented with modeling research. The theoretical OSF curves were obtained using the statistical mechanics approach. The experimental data and theoretical results for OSF for SDS micellar film were analyzed and found to be in fair agreement with each other. Based on the model prediction calculation, the structural film interaction energy barrier for the both the 0.03 M and 0.06 M SDS micellar solutions was calculated; the estimated structural film interaction energy barrier due to the presence of the OSF was about 10 3 kT / 􀝉􀬶 for the 0.03 M SDS micellar solution and about 5 x 10􀬷 kT /􀝉􀬶for the 0.06 M SDS micellar solution in film with micellar layers at about 25 ºC. Understanding the interactions between bacteria and solid surfaces that result in bacterial adsorption and removal is of immense importance for reducing foodborne illness outbreaks. Here, we used fluorescence microscope in conjunction with the concept of the diffusion of bacteria from the bulk suspension to the substrate and the adsorption isotherm to estimate the adsorption energy for E.coli K12; we obtained a value of about 2.5 kT. This value compares favorably with the value of 2.1 kT reported previously for E.coli NCTC 9002 [49]. We also used the dynamic light scattering method to estimate the radius of gyration of E.coli K12, which has a diameter of about 1 m and a length of 2 m to estimate the effective volume. The radius of gyration was also used to estimate the surface area covered by the bacterium and compared it to the surface area measured from the image taken with fluorescence microscope. A nanofluid formulation comprised of a sodium dodecyl sulfate (SDS) micellar aqueous solution in the presence of an organic acid (as a pH controller) was used to test the E. coli K12 removal from two substrates, polyvinylchloride (PVC) and partially hydrophobic glass. We investigated the bacterial removal efficacy based on the combined effect of the nanofluid’s structural forces and bacterial isoelectric point. We predicted the nanofilm oscillatory structural energy (NOSF) against the E.coli K12 adsorption energy by applying the statistical mechanics approach. Based on the model prediction, the NOSF was estimated at the vertex of three phase contact angle between a bacterium and the substrate (i.e., the wedge film’s interaction energy at one particle layer). The evaluated film’s repulsive energy due to the NOSF was about 15.6  4.4 kT of the 0.02 M SMNF (the SDS micellar nanofluid formulation) and several times higher than the bacterial adsorption energy, 2.5  0.2 kT. These findings suggest that the NOSF is capable of bacteria/microorganism removal from contaminated substrates. Here, we present a methodology based on NOSF to optimize the nanofluid formulation for bacterial substrate removal and bulk inactivation. The results of this study will assist the food industry with the design of proper sanitation and will enhance microbial removal and inactivation strategies.
Ph.D. in Chemical Engineering, May 2017
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Title: USER GENERATED DATA ANALYSIS AND UTILIZATION
Creator: Liu, Shizhu
Date: 2012-12-12, 2012-12
Description: Computer-mediated communication is becoming the most convenient and important way of sharing and exchanging information. The large volume and...
Show moreComputer-mediated communication is becoming the most convenient and important way of sharing and exchanging information. The large volume and diversity of user generated content as well as pervasive user opinions on the web make existing text processing methods ine cient and ine ective. Hence, there is a need for better ways of analyzing and utilizing user generated content. My thesis focuses on user generated data and is composed of two main parts: sentiment analysis and content analysis. I present a case study in which I use machine learning techniques to analyze real-world survey responses. Supervised techniques are exploited to classify customers' loyalty based on their comments and estimate a Net Promoter Score (NPS). NPS is a crucial indicator which has been used as a means of measuring survey results with a single estimator. I de ne three patterns to support generalized sentiment-bearing expression extraction, and design a set of heuristic rules to detect both explicit and implicit negations. By altering existing dependency with detected negations and generalized sentiment-bearing expressions I am able to construct more accurate sentiment features. Our results demonstrate that generalized dependency-based features are more e ective when compared to standard features. For content analysis, the thesis addresses the problem of user generated content summarization. I focus on two sub-problems: how to summarize the novel information from user generated content and how to present the evolutionary theme threads from temporal text collections with summaries. I design two speci c topic models for these two summarization tasks respectively. To discover similar and supplemental topics in user opinions with respect to the descriptive text provided by a publisher, I propose a semi-supervised generative model by casting the local publishers descriptive elds as a prior of a resembling topic. The most representative sentences in user opinions are classi ed based on their sentiment and used to construct a summary of x the comments. To track changes of topics in temporal text collections, I extend the probabilistic model to sentence level and use name entity to make the extracted theme thread easier to understand. Experimental results demonstrate the e ectiveness of the proposed models.
PH.D in Computer Science, December 2012
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Title: LAND USE EFFECTS ON WATER QUALITY: BUILDING A FRAMEWORK FOR CHICAGO RIVER WATERSHED
Creator: Mahdi, Naila Ghidey Ismail
Date: 2012-05-09, 2012-05
Description: The purpose of this study is to introduce a framework that enables a holistic watershed approach that models the dynamics of water quality and...
Show moreThe purpose of this study is to introduce a framework that enables a holistic watershed approach that models the dynamics of water quality and landuse in a highly urbanized watershed. The landuse-water quality relationship is a complex relationship and has not been adequately addressed for highly urbanized watersheds. Factors such as inadequate urban planning, increase of impervious areas and dynamics of population growth are some of the reasons for the complex relationship. Also point sources are always easy to be identified and controlled unlike nonpoint sources such as urban storm runoff. Both quantities and transport pathways of pollutant inputs are impacted by land use in the watershed. So, examining the factors that govern the relationship between different land uses and water quality within a watershed can give insights and important information about existing and potential sources of contamination. The two backbone concepts in this study are the holistic watershed perspective and the role of historical data records as part of assessment, modeling and integration tools of the watershed framework. Analysis of the records will explain watershed conditions identifying the major problem areas and justify the modeling and post analysis procedures. Data sources are often important but data availability, heterogeneity and conformity are the main challenges in integrating these sources. This research presents an approach to integrate the watershed data in a single repository and methodologies for analyzing and assessing the watershed using data warehouse and data mining technologies. A multi-dimensional model that supports complex querying of watershed data and discovery of trends and patterns in data by incorporating 40 years worth of watershed data from different source agencies in a central repository is introduced. Also, the discipline of data driven modeling was introduced in this thesis using the developed central repository. Several regression and classification algorithms were presented and assessed for their appropriateness for predicting total nitrates using few watershed attributes. The results show acceptable prediction accuracy. Five years of water quality simulation using the multi-purpose environmental analysis system BASINS coupled with the comprehensive, conceptual, and continuous simulation watershed scale model HSPF resulted in export coefficients for level (III), detailed land use for the Chicago River watershed. The water quality simulation approach utilized in this research to generate the coefficients constitutes a new contribution to the Chicago River watershed and other highly urbanized watersheds. The continuous calibrated and validated model can be used in the investigation and analysis of different scenarios and possible future conditions, thus providing a planning tool for regulatory environmental agencies. The data driven models developed can be used as operation tool to maintain the water quality parameters especially if TMDL and WQS are developed for Chicago River Watershed. So the framework proposed for this study can be considered robust with the proposed integration, planning and operating techniques and tools. Furthermore, an optimization tool is introduced in the future work section.
Ph.D. in Environmental Engineering, May 2012
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Title: TOWARDS REDUCING BUILDING ENERGY CONSUMPTION: COMPARISON OF THE RESIDENTIAL PLANNING PATTERNS IN BEIJING, SHANGHAI AND GUANGZHOU
Creator: Wang, Nan
Date: 2013, 2013-07
Description: The objective of this research is to investigate the influence of urban planning patterns on building energy consumption in different climate...
Show moreThe objective of this research is to investigate the influence of urban planning patterns on building energy consumption in different climate zones. Urban planning patterns affect the thermal performance and energy efficiency of buildings. This research focuses on the planning aspects, explores the energy consumption of a group of buildings with different planning pattern by utilizing single building as a baseline, and identifies planning patterns that can help to reduce the total heating and cooling energy consumption of the buildings. The investigations are carried out in the three largest cities in China – Beijing, Shanghai, and Guangzhou, which represent different climate zones. The results of these three cities are compared to find out the influence of local climate on building energy consumption. Different planning patterns are investigated in this research through changing building parameters: aspect ratio, orientation and layout. It is found that these parameters have important influence on reducing building’s energy consumption. It is also found that in different climate conditions, the influence of planning patterns on building’s energy consumption is different, which suggests that the selection of planning pattern will be different for each location. This research makes a significant contribution to the reduction of building energy consumption from urban planning perspective. In addition, two case studies of carefully selected residential communities with fixed site and fixed density are evaluated, and some suggestions for improvement are proposed as a result of the study. Such suggestions can help to propose a prototype model guiding the future architectural and urban planning work.
PH.D in Architecture, July 2013
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Title: ADVANCED BASE DRIVERS FOR SILICON CARBIDE BJTs
Creator: Pozo Arribas, Alejandro
Date: 2017, 2017-07
Description: This thesis focuses on the optimization of base drivers for SiC BJTs and presents a novel driver topology that targets minimum power...
Show moreThis thesis focuses on the optimization of base drivers for SiC BJTs and presents a novel driver topology that targets minimum power consumption. SiC BJTs have been studied for over a decade, during which time, they have been proven to have superior performance than Si IGBTs and even other normally-off SiC devices such as MOSFETs. Despite this, SiC BJTs are the least popular among the family of SiC power switches. As current controlled devices, BJTs require a continuous sup- ply of current through the base during the on-time. And, even though current gains over 100 have been reported, the base current required translates into a considerable amount power consumed by its driver, compared to its competitors. This power can affect the overall efficiency of a converter if the driver circuit is not designed properly. Since, the driver represents a key system for the success of SiC BJTs as power semiconductor devices, this thesis conducts a comprehensive evaluation of previous solutions and an analysis of the driver power losses to identify the optimal driver configuration. As a conclusion of this study, a novel topology is proposed, designed and built for its latter validation through experimental tests. The proposed solution allows the replacement of a SiC MOSFET or Si IGBT and driver with a SiC BJT and driver without the need of a current sensor or a dedicated DSP/FPGA. The driver power consumption is minimized with a proportional base current design based on a MHz synchronous buck converter operating as a Class D amplifier. This switched mode power amplifier uses a reference signal to provide a voltage that causes a base current proportional to the instantaneous collector current. The reference signal is generated with a high bandwidth sensor that measures the instantaneous voltage drop across the BJT (vCE) during the on-time. Hence, current sensors are avoided. Different alternatives for a voltage sensor are discussed and analyzed through simulations and experimental results. Moreover, the use of vCE to estimate the instantaneous collector current makes the proposed driver a temperature-sensitive design. For the first time, a proportional base current driver generates a base current proportional to the instantaneous collector current taking into account the effect of temperature on the DC current gain. Moreover, all this is achieved with solely analog electronics in a standalone solution. A 1.5kW Boost converter was built to validate the proposed driver under different collector currents and operating temperatures. In order to show the performance improvement offered by the proposed solution, the same Boost converter was operated with a commercial base current driver. This exercise showed a reduction of the driver power consumption by up to a factor of 4 without affecting the efficiency of the Boost converter. The switching behavior of a SiC BJT operated with the proposed driver and some of its limitations are discussed. These have, in fact, motivated additional research to develop efficient, isolated MHz regulators for faster operating frequencies of the SiC BJT. In addition, a new over-current protection integrated into the proposed driver is suggested and tested with interrupt times of less than 500ns for a collector current of 50A.
Ph.D. in Electrical Engineering, July 2017
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Title: THE EFFECT OF RUTHENIUM ADDITION ON THE PHASE EQUILIBRIA, MECHANICAL PROPERTIES AND OXIDATION RESISTANCE OF TIAL-BASED ALLOYS
Creator: Liu, Qizheng
Date: 2012-05-11, 2011-12
Description: The high temperature phase equilibria in the Ti-Al-Ru ternary system have been investigated but there remain some ambiguous regions. In this...
Show moreThe high temperature phase equilibria in the Ti-Al-Ru ternary system have been investigated but there remain some ambiguous regions. In this work arc-melted alloys were studied using scanning electron microscopy, X-ray diffraction and optical microscopy to determine the isothermal section of Ti-Al-Ru system at 1200°C. The lattice parameters were calculated from X-ray diffraction pattern for some compounds, including LI, 8-Ruso(TixAlso-x) and (AI6o-xTix)Ru4o. The lattice parameter of these three phases generally increases with Ti content. Enthalpy of formation was also measured for LI and 8-Ruso(TixAlso_x) with direct synthesis calorimeter to compare with the lattice parameter change. The enthalpy of formation of LI matches its lattice parameter change, but 8-Ruso(TixAlso_x) shows a reversed trend. It suggests that addition of Ti introduces a stronger bonding in the 8-B2 phase super-lattice. The phase equilibria are discussed in comparison with published research work. A new three phase region was detected for L t, Y and Til_xAl 1+x by X-ray diffraction. The homogeneity region of (AI6o-xTix)RU4o was found to be much higher than previously reported, with almost constant Ru content. The results from the ternary isothermal section also help to clarify the uncertain parts of the binary Ti-Al phase diagram. Three ternary eutectic reaction temperatures were measured with differential scanning calorimetry and the results were compared with the published liquidus projection. The high temperature compression behavior of TiAl-Ru alloys was studied at different temperatures and strain rates. Ru was found to have a strong strengthening effect on TiAI alloys. However the Ru addition amount was limited by its low solubility in y-TiAI and U2-Ti3AI, and the detrimental effect of excessive ternary phase precipitation. Furthermore, the melting temperature decreases when Ru 2:0.6at% as the alloy composition approaches a ternary eutectic point. The strengthening mechanism is discussed and two separate mechanisms are proposed, viz. solid solution strengthening and refined colony strengthening. Intergranular cracks were found in the alloys with low Ru or no Ru addition, but were barely detected as Ru content increased to above 0.6 at.%. It was suggested that Ru showed a beneficial effect on both strength and ductility of TiAI alloys due to the refined colony size. Three-point bend test results showed that the Ru addition can also improve the room temperature ductility of TiAl alloys. Hot workability was increased according to the compression tests. Thermal-mechanically treated TiAI-Ru had much smaller grain size than the heat-treated samples due to dynamic recrystallization. But it did not show superior strength in the compression test compared to the heat-treated samples. The Zener-Hollomon parameter was calculated from the compression strength of heat-treated TiAI-Ru alloys. Its relationship with dynamic recrystallization and hot work is discussed. The mechanical properties of TiAI-Ru alloys are compared with TiAI-Nb samples and demonstrate a promising combination of strength and ductility. The high-temperature oxidation resistance ofTiAI alloys with constant AI content and different alloying elements was tested with thermogravimetric calorimeter. Both Ru and Nb additions were found to have beneficial effect on the oxidation resistance ofTiAI alloys. While TiAI-Ru showed a slight improvement on the oxidation behavior, TiAI-Nb alloys had much better performance in comparison with TiAI alloys. Complicated oxide scale structure was characterized with the assistance of X-ray diffraction, scanning electron microscopy and Energy-dispersive X-ray spectroscopy analysis. The different oxide scale structure among the TiAl, TiAl-Ru and TiAl-Nb alloys were discussed with respect to their thickness, spatial pattern and composition gradient. The poor oxidation resistance of TiAI alloys at the testing temperature was determined to be attributed to the competition growth between Ah03 as well as Ti02, and the lack of a thick continuous Ah03 layer. The outward diffusion of Ti was found to be the controlling factor and the growth of Ti02 on top level of the oxide scale destroyed the initial Ah03 protection. RU02 was found to be the natural marker of the oxidation process in TiAl-Ru alloys due to its slow diffusion. The repartitioning of Ru in the oxide/substrate boundary was revealed to be the reason of its slight beneficial effect. Nb20 S layer was observed in the oxide scale of TiAl-Nb alloys and it played the role of blocking the outward diffusion of Ti. Thus Nb addition can suppress the growth of Ti02 and promote the formation of a continuous AI 20 3 layer. Treating the TiAI alloys by dipping in hydrofluoric (HF) acid was found to have a dramatic beneficial effect on TiAI alloys. Alloying elements have reversed effect on the HF dipping due to the reduced reaction rate with HF acid. The oxidation rate constant and activation energy were calculated for TiAI alloys with/without alloying addition. They were compared with the published data and the trend with composition change was discussed.
Ph.D. in Materials Science and Engineering, December 2011
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Title: SECURITY AND PERFORMANCE OPTIMIZATION FOR WIRELESS COMMUNICATIONS
Creator: Wang, Qian
Date: 2012-04-13, 2012-05
Description: Today’s communication systems rely heavily on wireless technologies. The large scale proliferation of wireless technology brings with it a...
Show moreToday’s communication systems rely heavily on wireless technologies. The large scale proliferation of wireless technology brings with it a more serious concern for security since wireless communications introduce multiple avenues for attack and penetration into a network. This dissertation studies two important and fundamental problems in wireless communication security: secure secret key establishment and anti-jamming communication. This dissertation extends the current body of knowledge by proposing a suite of new and novel solutions to enhance and optimize the system performance. A comprehensive study including theoretical analysis and simulative evaluation shows that the proposed solutions can be applied in highly dynamic networking scenarios where traditional security mechanisms may not be sufficient by themselves. The first part of this dissertation develops a novel cooperative key generation protocol to facilitate high-rate key generation in narrowband fading channels, where two keying nodes extract the phase randomness of the fading channel with the aid of relay node(s). In particular, a theoretical upper bound and a more practical upper bound on the maximum secret key rate are successfully established. Numerical examples and simulation studies are also presented to demonstrate that the key rate can be improved by a couple of orders of magnitude compared to the existing physical layer based key generation approaches. The second part of this dissertation develops an adaptive uncoordinated frequency hopping (UFH) protocol for anti-jamming wireless communications. This section of the dissertation introduces the online optimization theory into the solution space and makes the thorough quantitative performance characterization possible for UFH-based anti-jamming communications. The optimality of the proposed algorithms is analytically proved under various message coding scenarios. Simulation results are presented demonstrating the jamming resilience of the learning-based UFH algorithm. The final part of this dissertation presents a jamming-resistant multi-radio multi-channel opportunistic spectrum access protocol for cognitive radio networks (CRNs), where the secondary sender and receiver adaptively choose their channels to operate to maximize the throughput. The convergence of the learning algorithm is investigated and an upper bound on the performance difference between the secondary sender and receiver’s optimal strategies is obtained. The simulation results in this section validate the theoretical analysis and show that even if facing a powerful jammer using myopic policy, the proposed design is still very effective and has strong resilience against jamming.
Ph.D. in Electrical Engineering, May 2012
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Title: LOCALIZATION OF WIND TURBINE NOISE USING A COMPACT MICROPHONE ARRAY WITH ADVANCED BEAMFORMING ALGORITHMS
Creator: Ramachandran, Rakesh Chandran
Date: 2014, 2014-12
Description: The knowledge of noise source location on a wind turbine is crucial for de- signing low noise wind turbines. Even though there has been...
Show moreThe knowledge of noise source location on a wind turbine is crucial for de- signing low noise wind turbines. Even though there has been considerable e ort to theoretically predict the noise from wind turbines in the past, very few experimental investigations have been performed to validate these models. Currently, compliance standards for wind turbine noise are based on single microphone measurements at various designated locations around a wind turbine. This only provides amplitude and frequency data of the overall wind turbine noise. However, it is impossible to locate noise sources, and to understand the dominant noise generation mechanism, using single microphone measurements. A sophisticated method, namely, the use of a microphone phased array with beamforming is necessary to locate the noise sources. Even though microphone arrays have been widely used to study aircraft yover and jet noise, it has just recently found application in locating wind turbine noise. Typical microphone arrays that have been used in the past for monitoring aircraft noise and wind turbine noise are very large ranging up to 270 m2 in area with about 148 mi- crophones. The setup is xed for a particular wind turbine and takes a considerable amount of time. In this thesis it is shown that a compact microphone array (with 24 microphones spread over 1.5 m2) is su cient to locate and separate wind turbine noise sources successfully. It is also shown that in order to use a compact micro- phone array, advanced deconvolution based beamforming methods such as DAMAS, CLEAN-SC, LP, and TIDY are necessary. However, before attempting to validate our idea, it is necessary to understand the concept of array resolution and di erent methods to improve it. We start with an in-depth study on the microphone array resolution and the e ect of di erent beamforming algorithms on it. This study has resulted in several interesting results: (i) The resolution limits that govern the resolution of the imaging system in optics also govern the resolution of microphone array. (ii) The resolution is a function of source frequency, diameter of the array, separation distance between sources, and the distance between the array and the sources. (iii) The resolution lost due to the compact microphone array can be recovered by using deconvolution algorithms. (iv) Di erent algorithms are useful for di erent scenarios; CLEAN-SC is most e cient in extracting the dominant noise source from the source map, LP is e cient in locating multiple or extended noise sources, and TIDY is e cient in locating moving sources. (v) LP and DAMAS show superresolution. (vi) The dynamic range of source maps could be improved by eliminating the diagonal elements of CSM or CCM but care should be take as this could also eliminate weak sources. Following this study, we discuss the results from the full scale large wind tur- bine noise measurements. Our study focuses on the ability of a compact microphone array to successfully locate both mechanical and aerodynamic noise sources on the wind turbine. Several interesting results have emerged from this study: (i) A compact microphone array is su cient to perform a detailed study on wind turbine noise if advanced deconvolution methods are applied. (ii) Noise sources on the blade and on the nacelle can clearly be separated. (iii) Noise of the blades is dominated by trailing edge noise which is frequency dependent and is distributed along the length of the blade with the dominant noise source closer to the tip of the blade. (iv) The LP and DAMAS algorithms represent the distributed trailing edge noise source better than CLEAN-SC and conventional beamforming. (v) Additional tonal noise produced dur- ing yawing operation is believed to be radiating from the tower of the wind turbine that acts like a resonator. (vi) Ground re ection is not believed to have a signi cant e ect on noise source location estimates in this study. (vii) The asymmetry in the aerodynamic noise is attributed to the Doppler ampli cation e ect. Finally, the noise measurements made on the small scale wind turbine showed that the compact array was successfully able to separate out the mechanical and aerodynamic noise. The mechanical noise from the nacelle was found to be the dominant noise source below 3000 Hz and the aerodynamic noise from the blades was found to be dominant above 3000 Hz. The asymmetry in the aerodynamic noise was also present in this case. The study on mechanical noise found that gear box was the dominant noise source. It is hoped that the work presented in this thesis will serve as a guide to researchers who intend to use compact microphone arrays with advanced beamforming algorithms in the future and also to those who intend to validate theoretical models of wind turbine noise.
Ph.D. in Mechanical and Aerospace Engineering, December 2014
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Title: METHODOLOGY FOR PERFORMANCE BASED TRANSPORTATION SYSTEMS MANAGEMENT SIMULTANEOUSLY CONSIDERING DEMAND AND SUPPLY, WITH PRICING CONSIDERAnON
Creator: Patel, Harshingar
Date: 2015, 2015-05
Description: The ever growing demands for the use of transportation infrastructure and its maintenance and repairs at an acceptable level of service are...
Show moreThe ever growing demands for the use of transportation infrastructure and its maintenance and repairs at an acceptable level of service are the prime concern for transportation agencies today. The available financial resources can never be sufficient to match the exorbitantly high requirements for construction, maintenance and rehabilitation of transportation systems. With the advent of the technological revolution, the intelligence transfer amongst various engineering fields has made it possible to reduce transportation costs. However, the slow growing budget caused by economic recession and revenue decrease over time puts transportation agencies under enormous pressure to effectively restore the deteriorated transportation facility and system operation conditions under the budget constraint. The proposed research aims to utilize the concept of roadway pricing coupled with a holistic framework of asset management to support performance-based management of transportation systems and help transportation agencies achieve the future vision of the nation's strategic planning requirements to enable sustainable management of the system. A computational study for the City of Chicago’s central district is conducted by using the proposed roadway pricing framework. The proposed roadway pricing framework can be utilized for urban as well as rural regions, by public as well as private agencies, to manage the system in a sustainable manner, by means of fair pricing to the users of the system, for their facility condition and usage impacts.
Ph.D. in Civil Engineering, May 2015
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Title: 3D COMPRESSION ALGORITHMS AND SYSTEM-ON-CHIP DESIGN FOR ULTRASONIC IMAGING APPLICATIONS
Creator: Govindan, Pramod
Date: 2015, 2015-05
Description: Ultrasonic systems are widely used in imaging applications for nondestructive evaluation, quality assurance and medical diagnosis. These...
Show moreUltrasonic systems are widely used in imaging applications for nondestructive evaluation, quality assurance and medical diagnosis. These applications require large volumes of data to be processed, stored, and/or transmitted in real-time. Therefore, it is essential to compress the acquired ultrasonic radio frequency (RF) signal without inadvertently degrading desirable signal features. Signal fidelity, computational speed and resource utilization are the major parameters to be considered while designing the architecture for the compression algorithm. In this study, two algorithms for ultrasonic signal compression are analyzed based on: sub-band elimination using discrete wavelet transform; and decimation/interpolation using time-shift property of Fourier transform. Both algorithms offer high signal reconstruction quality with a peak signal-to-noise ratio (PSNR) between 36 dB to 39 dB for minimum 80% compression. The computational loads and signal reconstruction quality are examined in order to determine the best compression method in terms of the choice of DWT kernel, sub-band decomposition architecture and computational efficiency. Furthermore, for compressing a large amount of volumetric information, 3D compression algorithms are designed by utilizing the temporal and spatial correlation properties of the ultrasonic RF signals. The performance analysis indicates that the 3D compression algorithm presented in this study offers an overall 3D compression ratio of 95% with a minimum PSNR of 27 dB. Furthermore, the DWT based ultrasonic 3D data compression algorithm is implemented on a reconfigurable ultrasonic system-on-chip hardware platform targeted for real-time ultrasonic imaging applications. The reconfigurable platform allows analysis of multiple architectures to suit various applications. In this study, hardware andtemporal and spatial correlation properties of the ultrasonic RF signals. The performance analysis indicates that the 3D compression algorithm presented in this study offers an overall 3D compression ratio of 95% with a minimum PSNR of 27 dB. Furthermore, the DWT based ultrasonic 3D data compression algorithm is implemented on a reconfigurable ultrasonic system-on-chip hardware platform targeted for real-time ultrasonic imaging applications. The reconfigurable platform allows analysis of multiple architectures to suit various applications. In this study, hardware and software architectures of the 3D ultrasonic compression algorithm implemented on Xilinx Zynq all programmable system-on-chip platform are discussed, along with the analysis of computational performance. Both implementations provide a high signal compression ratio of about 98% with good quality signal reconstruction. This study demonstrates that, compressing 33 MBytes of experimental ultrasonic 3D data into 0.42 MBytes requires only 84 millisecond for hardware architecture, and one minute for software architecture, making both designs highly suitable for real-time ultrasonic imaging applications. Furthermore, the 3D compression is implemented by using OpenCL, which is adaptable to various platforms such as CPUs, GPUs and FPGAs. Therefore, OpenCL provides similar computational performance as that of hardware architecture, and the same flexibility as that of software implementation. This study demonstrates that the OpenCL implementation of ultrasonic 3D compression algorithm on Nvidia GT 750M graphical processing unit (GPU) completes the operation in less than one second.
Ph.D. in Electrical and Computer Engineering, May 2015
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Title: NETWORK SELECTION WITH LOAD MANAGEMENT IN HETEROGENEOUS WIRELESS NETWORKS
Creator: Ahmed, Syed Qutubuddin
Date: 2013, 2013-12
Description: With the growth of data-capable, multi-interface wireless and mobile devices, a lot of research work is being done on handover management and...
Show moreWith the growth of data-capable, multi-interface wireless and mobile devices, a lot of research work is being done on handover management and network selection in heterogeneous environment. Many researchers have proposed several strategies and policies for selecting the appropriate network. These policies di er among each other due to various reasons. The state and load of networks, number and types of wireless networks considered, and preferences of users are some of the reasons that attribute to di erences in those proposed policies. As a result, the applicability and e ciency of those policies depend upon certain situations and circumstances. We propose, in this research, a new concept that will help in utilizing these various policies in a manner that will give better results in a longer run and in various kinds of situations. We have a pool of policies available, and our proposed method will select the policy that is most appropriate according to the current state of user. We modeled this problem as a Markov Decision Process. Since the overall goal is that a user should be able to select an appropriate wireless network according to its service requirements and seamlessly handover to that network regardless of the underlying wireless technology being used. Since di erent sets of methodologies can exist to deal with this issue, we also propose an alternative mechanism that would facilitate a particular user to connect to the most appropriate network in a way that is bene cial to the overall network and its users as a whole. A trusted third party entity receives handover requests from a set of users along with their preferences, takes into consideration current network state of available service providers, and assigns each user to an appropriate network resource. We call this mechanism "Network Assisted Network Selection (NANS)" and it combines network-based, service-based and user-based criteria for network selection, and uses Generalized Assignment Problem (GAP) to assign the network resources to a set of users. ix Mobile Access Gateway (MAG) is a component of Proxy Mobile IPv6 (PMIPv6) which provides network-layer transparent mobility to mobile nodes (MN). MAG serves a local geographical area and mobile nodes in its vicinity may attach to it to get the mobility services from its controlling PMIPV6 domain. Since MAG is the point of attachment of mobile nodes, negotiated and guaranteed quality of service (QoS) is af- fected in case of service disruptions and overload of the MAG. To avoid and minimize the degradation of quality of service, we propose e ective mechanisms to share the load of a ected MAG with the MAG(s) that are working under normal conditions. We propose to handover certain mobile nodes to other MAGs depending upon their geographical serving area and current capacity. Furthermore, location of mobile node, its quality of service pro le, direction of motion and its multi-interface capability are major factors in selecting the mobile nodes for handover.
PH.D in Computer Engineering, December 2013
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Title: ANALYZING REPRODUCING KERNEL APPROXIMATION METHODS VIA A GREEN FUNCTION APPROACH
Creator: Ye, Qi
Date: 2012-04-22, 2012-05
Description: In this thesis, we use Green functions (kernels) to set up reproducing kernels such that their related reproducing kernel Hilbert spaces ...
Show moreIn this thesis, we use Green functions (kernels) to set up reproducing kernels such that their related reproducing kernel Hilbert spaces (native spaces) are isometrically embedded into or even are isometrically equivalent to generalized Sobolev spaces. These generalized Sobolev spaces are set up with the help of a vector distributional operator P consisting of finitely or countably many elements, and possibly a vector boundary operator B. The above Green functions can be computed by the distributional operator L := P TP with possible boundary conditions given by B. In order to support this claim we ensure that the distributional adjoint operator P of P is well-defined in the distributional sense. The types of distributional operators we consider include not only di erential operators but also more general distributional operators such as pseudo-di erential operators. The generalized Sobolev spaces can cover even classical Sobolev spaces and Beppo-Levi spaces. The well-known examples covered by our theories include thin-plate splines, Mat´ern functions, Gaussian kernels, min kernels and others. As an application for high-dimensional approximations, we can use the Green functions to construct a multivariate minimum-norm interpolant s f;X to interpolate the data values sampled from an unknown generalized Sobolev function f at data sites X Rd. Moreover, we also use Green functions to set up reproducing kernel Banach spaces, which can be equivalent to classical Sobolev spaces. This is a new tool for support vector machines. Finally, we show that stochastic Gaussian fields can be well-defined on the generalized Sobolev spaces. According to these Gaussian-field constructions, we find that kernel-based collocation methods can be used to approximate the numerical solutions of high-dimensional stochastic partial differential equations.
Ph.D. in Applied Mathematics
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Title: AGENT-BASED MODELING OF ANGIOGENESIS WITHIN DEGRADABLE BIOMATERIAL SCAFFOLDS
Creator: Mehdizadeh, Hamidreza
Date: 2013, 2013-12
Description: The ability to promote and control blood vessel assembly in polymer scaffolds is important for clinical success in tissue engineering. Often,...
Show moreThe ability to promote and control blood vessel assembly in polymer scaffolds is important for clinical success in tissue engineering. Often, experimental studies are performed to investigate the role of scaffold architecture on vascularized tissue formation. However, experiments are expensive and time-consuming and synthesis protocols often do not allow for independent investigation of specific scaffold properties. Mathematical and computational representation of the relationship between scaffold properties and neovascularization facilitates studying the fundamental processes involved in vascularization of biomaterials and provides more profound understanding of the critical factors that affect this process. This understanding is critical for the design of new therapeutic approaches that could bridge the existing gap between current experimental techniques and the state of the art practical tissue regeneration approaches. Computational models allow for rapid screening of potential material designs with control over scaffold properties that is difficult in laboratory settings. In this work, a multi-layered, multi-agent framework is developed to model the process of sprouting angiogenesis within porous biodegradable tissue engineering scaffolds. Software agents are designed to represent endothelial cells, interacting together and with their micro-environment, leading to formation of new blood vessels that perfuse the scaffold. A rule base, derived from the experimental findings reported in the literature, or observed by our collaborators, governs the behavior of individual agents. Two-dimensional and three-dimensional scaffold models with well-defined homogeneous and heterogeneous pore architectures are designed and simulated to investigate the impact of various scaffold design parameters such as pore size, pore size distribution, interconnectivity, and porosity, as well as the degradation behavior of 2 the scaffolds, on vessel invasion and capillary network structure. Model parameters such as the speed of vessel sprouting or cell migration speed are adjusted based on independent results of in vivo vascularization of fibrin gels in the absence of a polymer scaffold. The effects of various characteristics of scaffold degradation are also investigated. Various scenarios are defined and simulation case studies are developed to investigate the effect of scaffold geometrical and structural properties on angiogenesis. The simulation results are compared with available experimental results of scaffold vascularization performed in our group and with relevant published literature data to validate the developed model. These results indicate that in general the rate of vascularization increases with larger pore size and higher interconnectivity and porosity scaffolds. Pores of larger size (160-270 μm) support rapid and extensive angiogenesis, however vascularizing deeper parts of the scaffolds still remains a challenge that requires more complex scaffold designs. The agent-based model can be used to provide insight into optimal scaffold properties that support vascularization of engineered tissues. The modeling framework developed provides a novel interface for convenient integration of new knowledge to the current computational models, making it possible to gradually increase the level of complexity and accuracy of the models as our knowledge about the underlying biological system advances. The simulation results help us better understand the complex interactions between the growing blood vessel network and a degrading scaffold structure, and identify the optimal combinations of geometric and degradation characteristics of tissue engineering scaffolds that support scaffold vascularization.
PH.D in Chemical Engineering, December 2013
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Title: INVESTIGATING THE MEDIATION OF HEMOGLOBIN PROTEINS IN NITRIFICATION AT LOW DISSOLVED OXYGEN CONDITIONS
Creator: Arnaldos, Marina Orts
Date: 2012-10-30, 2012-12
Description: Due to the high aeration and energy requirements of nitrifying activated sludge processes, there is great interest in developing biological...
Show moreDue to the high aeration and energy requirements of nitrifying activated sludge processes, there is great interest in developing biological nitrifying processes that operate efficiently under low dissolved oxygen (DO) conditions. In this framework, the present study has investigated the acclimation of ammonia-oxidizing communities (AOC) to low DO concentrations. Under controlled laboratory conditions, two sequencing batch reactors seeded with activated sludge from the same source were operated at high DO (near saturation) and low DO (0.1 mg O2/L) concentrations for a period of 385 days. Stable and complete nitrification at low DO after an acclimation period of approximately 140 days was demonstrated. Modeling of oxygen transfer and uptake behavior demonstrated the low DO reactor to achieve equal performance to the high DO reactor, when the latter is operated at design DO concentration (2 mg O2/L), with approximately 20 % improvement in aeration requirements and oxygen mass transfer efficiency. The effect of DO on AOC dynamics was evaluated using the 16S rRNA gene as the basis for phylogenetic comparisons and organism quantification. Ammonium consumption by ammonia-oxidizing archaea and anaerobic ammonia-oxidizing bacteria was ruled out in both reactors. Even though N. europaea was the dominant AOB lineage in both SBRs at the end of operation, this enrichment could not be linked to acclimation to oxygen-limited conditions. This finding challenges the hypothesis that low DO conditions select for ammonia-oxidizing lineages characterized by high oxygen affinities, and points to the alternative mechanism of a physiological change of a generalist nitrifying community. Acclimation brought about increased specific oxygen uptake rates and enhanced expression of a particular heme protein in the soluble fraction of the biomass in the low DO reactor as compared to the high DO reactor. The heme protein induced was determined not to be any of the enzymes playing a role in ammonia metabolism of ammonia oxidizing bacteria, including a soluble oxidase and soluble peroxidase of unknown function. Further molecular studies are required to verify the hypothesis put forward in this study that the heme protein detected is a hemoglobin.
PH.D in Environmental Engineering, December 2012
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Title: ELECTROCHEMICAL ANALYSIS OF ACTINIDES IN MOLTTIN SALTS
Creator: Tylka, Magdalena
Date: 2015, 2015-05
Description: In electrochemical studies, the measured parameter (potential, current, or charge) is related to the quantity of the analyte in the solution...
Show moreIn electrochemical studies, the measured parameter (potential, current, or charge) is related to the quantity of the analyte in the solution and therefore can serve as an analytical signal for concentration measurements. The aim of this work is to develop high precision, real-time, quantitative, electroanalytical measurements of the concentrations of actinide chlorices in molten salts for monitoring pyrochemical process. Possible reasons for discrepancies found in the literature among electrochemically-measured values have been identified and methods to improve their precision have been established. Specific procedures were developed to refine both experimental techniques and data analysis methods. By following these procedures, precise and reproducible measurements were obtained for U and Pu in LiCl/KCl eutectic at 500°C. The effect of varying concentration on the method was investigated. In particular, the applicability of the techniques at high concentration of the analyte is evaluated. In addition to this, samples containing more than one analyte are considered, and the development of a modified data analysis method, required for their quantitative analysis, is described. Comparison of results obtained from improved electroanalytical measurements, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis, are shown and discussed. In addition to this, analysis of current-time transients, following a potential step, provide fundamental information about nucleation and growth of actinides on inert electrodes from molten salts. The effect of different concentrations of electroactive species, the applied potential, and the material of the working electrode on nucleation parameters are examined and discussed.
Ph.D. in Chemical Engineering, May 2015
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Title: SMART GRID COORDINATION IN BUILDING HVAC SYSTEMS
Creator: Mendoza Serrano, David Israel
Date: 2013, 2013-12
Description: In the context of real time electricity pricing, energy consumption by Heating, Ventilation, and Air Conditioning (HVAC) systems is usually...
Show moreIn the context of real time electricity pricing, energy consumption by Heating, Ventilation, and Air Conditioning (HVAC) systems is usually heaviest when prices are at their highest. In order to reduce expenditure while adequately maintaining indoor comfort conditions, Economic Model Predictive Control (EMPC) policies can be implemented in conjunction with Thermal Energy Storage (TES). This equipment con guration allows the time-shift of chiller power consumption away from periods of high demand to periods of low energy cost. Overcoming the main drawbacks intrinsic to EMPC policies constitutes the initial focus of this work. The rst issue concerns the susceptibility of EMPC to disturbance prediction quality, as this algorithm relies on weather and electricity price forecasts to generate control actions. Thus, two gray box models of increasing complexity are developed to illustrate the fundamentals of disturbance forecasting with shaping lters. Additionally, two data driven models are also presented for comparison. The discussion is then expanded to forecasting quality based on the amount of information available, and proper economic evaluation of these scenarios with gray and black box models is performed. The second issue of interest is related to the susceptibility of EMPC to prediction horizon, since this methodology computes control actions based on a receding horizon framework. Usually, control policies that reduce expenditure the most also rely on relatively large horizon sizes. These implementations tend to result in considerable computational burden. While horizon size reductions are commonly used to lessen the associated computational needs, they also carry signi cant economic performance degradations. To solve this issue, a novel Economic Linear Optimal Control (ELOC) capable of enforcing constraints statistically is developed. Additionally, the ELOC feedback is used to generate a receding horizon formulation capable of enforcing point-wise-in-time constraints, termed constrained viii ELOC. This algorithm is virtually insensitive to horizon size while retaining and even surpassing the economic performance of EMPC. The third major achievement of this work is the development of an HVAC equipment sizing and optimization methodology. This goal is achieved through the implementation of a gradient search algorithm designed to predict returns on investment based on a net present value analysis. As part of this technique, the ELOC and constrained ELOC methodologies are expanded for equipment design. The successful implementation and convergence of this numeric optimization is illustrated with a case study.
PH.D in Chemical Engineering, December 2013
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Title: WIND TURBINE FARMS IMPACT ON POLLEN TRANSPORT DISPERSION PATTER S
Creator: Hsu, Chin Yu
Date: 2012-11-28, 2012-12
Description: Wind energy has become more and more popular because electricity generation by wind power brings much less environmental impacts than...
Show moreWind energy has become more and more popular because electricity generation by wind power brings much less environmental impacts than conventional energy generation using coal. Also, energy generated by wind power does not require expensive fuel imported from overseas. Since the land in between turbines is still cultivated for crops and grazing, it is important to know the potential interference of wind turbines with pollen transport and dispersion, or the possible change of patterns established for thousands of years. However, these issues have not been studied in the literature. The co-existence of conventional crops with genetically modified (GM) crops has become a subject of debate. In particular, pollen transfer from GM crops to non-GM crops might result in the introgression of transgenes into natural populations as maize is mainly wind-pollinated. This study thus reports and assesses a comprehensive method that estimates maize pollen transport in the presence of turbines to ascertain the potential for maize pollen transport. The study on the concentrations of maize pollen transport affected by the wind turbines considers different dispersion parameters given the additional mechanical turbulence introduced by the presence of operating wind turbines. For instance, the wind turbines can increase surface roughness which subsequently causes increased mechanical turbulence. A high mechanical turbulence subsequently reduces downwind concentrations because of the mixing higher and wider into the atmosphere, which dilutes the maize pollen plume with more clean air. This study compares maize hourly concentrations and ground level flux levels inside and outside a virtual maize flux in the presence and absence of operating wind turbines. Results from a 14-day simulation of maize transport xii with and without operating wind turbines indicate that each difference of corresponding concentration and flux levels is statistically significant. Likewise, patterns of maize pollen transport inside the farm with turbine effects are significantly different from those without turbine effects. Overall, the average maize pollen concentration inside the farm in the absence of turbine effects is about 5 times greater than the corresponding maize pollen concentration with turbine effects. The total mass of maize pollen released into the air is the same whether the wind turbines are present or not. The portion of maize pollen staying inside the farm, on the other hand, is influenced by turbulence. For instance, the increased surface roughness caused by the turbine effects will increase the mechanical turbulence. Because the high mechanical turbulence carries a large portion of maize pollen away from the farm, only a small portion of maize pollen stays inside the farm due to the high turbulence that lifts maize pollen into higher levels of flow where the wind speed is stronger. In contrast, without turbine effects, a small portion of maize pollen leaves the farm while most of it deposits on the ground much sooner than it would with turbine effects. Therefore, maize pollen concentration and ground level flux in the presence of turbine effects will be greater than they are without turbine effects at a relatively far distance from the farm.
PH.D in Environmental Engineering, December 2012
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Title: DEVELOPMENT OF PERMEABLE REACTIVE FILTER SYSTEMS (PRFS) FOR TREATMENT OF URBAN STORMWATER RUNOFF
Creator: Prabhukumar, Giridhar
Date: 2013, 2013-05
Description: Urban stormwater runoff is a major contributor of pollutants to nearshore beach water of Lake Michigan and other water bodies. Reduction of...
Show moreUrban stormwater runoff is a major contributor of pollutants to nearshore beach water of Lake Michigan and other water bodies. Reduction of pollutants levels to within safe limits in urban runoff from near shore areas by means of filtration using low-impact reactive multi-media systems is the subject of research in this dissertation. The key research issues addressed are the identification of effective filter materials and laboratory-scale testing of the selected materials for permeable reactive filter systems (PRFS) that are feasible for installation in urban environment. The focus was to evaluate different media materials for removal of total suspended solids (TSS), nutrients (nitrate and phosphate), heavy metals (Cd, Cr, Cu, Pb, Ni and Zn), polycyclic aromatic hydrocarbons (naphthalene and phenanthrene) and microbial (E. coli.) contaminants from stormwater runoff to levels below standard discharge criteria. Eight different media materials were initially selected, including calcite, anthracite coal, zeolite, sand, iron-oxide coated sand (IOCS), iron filings, perlite and biochar. Of these, calcite (C), zeolite (Z), sand (S) and iron filings (Fe0) were screened based on preliminary column experiment results and used for further studies. Physical and chemical characterization studies were carried out to understand the material properties. Contaminant attenuation studies with lab-scale column experiments for the four individual media materials (C, Z, S and Fe0) were conducted with synthetic stormwater solution containing all the aforementioned pollutants. Results showed that calcite and sand were efficient in TSS, nutrients and polycyclic aromatic hydrocarbons (PAHs) removal, zeolite was efficient for metals removal and the only material that was able to lower E. coli level to below its safe xv limit of 126 most probable number (MPN) per 100ml, and iron filings was efficient in nutrients and metals removal. Column experiments were also conducted with three mixed media compositions, C-Z-S, C-Z-Fe0 and C-Z-S-Fe0. The results indicated that a multi-media based filtration system can perform efficiently to treat a wide range of pollutants and runoff flow conditions. Finally, several conceptual designs for PRFS were proposed that are suitable for application at various urban locations.
PH.D in Environmental Engineering, May 2013
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