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Title: Strategies for Improved Biodesulfurization in Genetically Engineered E.Coli Hosts
Creator: Ranganathan, Abhaya
Date: 2011-04-20, 2011-05
Description: Biodesulfurization has been an area of active research for the past few decades, in an effort to curb the amount of sulfur byproducts released...
Show moreBiodesulfurization has been an area of active research for the past few decades, in an effort to curb the amount of sulfur byproducts released into the environment. One key aspect of sulfur removal using biological techniques is the microbial conversion/utilization of dibenzothiopene (DBT), an ubiquitous component of organic sulfur compounds of crude oil. Three main enzymes are involved in 4S pathway of biodesulfurization; they are DszA, DszB, and DszC. DszD is a fourth enzyme that provides the necessary cofactors to Dsz A and DszC to complete their monooxygenase reactions in a number of bacteria with desulfurization capability, such as Rhodococcus erythropolis IGTS8. In this study, two ways to engineer bacteria, especially E. coli, for improved biodesulfurization of crude oil were investigated. The first was to express the dszD gene in E. coli in conjunction with the dszABC operon and study its effect on the growth pattern of the cells in minimal medium with DBT as the sole source of sulfur. The second approach was to clone the gene encoding sulpeptide S2, which is a sulfur-rich polypeptide, along with the desulfurization operon so that expression of sulpeptide would increase the demand for sulfur by the host cells. dszD and S2 were successfully cloned downstream of existing constructs of pGEM T-easy dszABC and pNW33N dszABCD and were expressed in E. coli strains BL21 and DH5α respectively. Growth experiments indicated marginal increase in the presence of dszABC compared to the unengineered strain and in the presence of dszD and S2; however, improved desulfurization activity was observed in the case of cells harboring dszD in addition to the dszABC operon.
M.S. in Biology, May 2011
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Title: A MASTER PLAN FOR A DETROIT NEIGHBORHOOD MADE IN DETROIT
Creator: Rios, Adriana Teresa
Date: 2014, 2014-05
Description: A MASTER PLAN FOR A DETROIT NEIGHBORHOOD MADE IN DETROIT Adriana Teresa Rios, M.S.Arch Illinois Institute of Technology, May 2014 Adviser: Tom...
Show moreA MASTER PLAN FOR A DETROIT NEIGHBORHOOD MADE IN DETROIT Adriana Teresa Rios, M.S.Arch Illinois Institute of Technology, May 2014 Adviser: Tom Brock Co-Adviser: George Schipporeit This thesis was written on behalf of the Sustainable New Cities program for the Illinois Institute of Technology. The goal of this Thesis is to establish a working definition of sustainability and the framework necessary for rebuilding a neighborhood in Detroit. The neighborhood in this Thesis being rebuilt is directly Southwest of Downtown Detroit. For the purpose of this thesis, sustainability is defined materially, socially, environmentally and economically. The plan for this Thesis is accomplished in phases to allow for an appropriately sized and conscientiously executed change. There is a large portion devoted to the history of Detroit and current state of the city; the reason for such an examination is to fully understand the past mistakes and successes throughout the history of Detroit. The systems and infrastructure designed in this Thesis effectively create a walkable thriving community that is diverse in it’s ecology, economy, and demographics. A major component for making this Thesis viable is the design of a Technology Campus that will collaborate with the city, local universities, and various technical companies to educate and train existing and new members of the local population. The second intergral aspect of this design is the light rail that will improve and simplify transportation outside of automobile traffic. Aside from the tangible infrastructure benchmarks, this Thesis also establishes the necessary theory behind a neighborhood that will continue to grow change and thrive. This Thesis has achieved a plan that considers all aspects of reconfiguring a neighborhood with sustainability as the focus.
M.S. in Architecture, May 2014
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Title: AN INTEGRATED FRAMEWORK FOR OPIMIZING TRAVEL TIME FOR CARS IN SMART CITIES
Creator: Al Hassan, Reida
Date: 2015, 2015-12
Description: This thesis proposes three different approaches for optimizing the travel time of cars in large networks. Genetic Algorithm with the...
Show moreThis thesis proposes three different approaches for optimizing the travel time of cars in large networks. Genetic Algorithm with the integration of microscopic traffic simulation is employed to search for global solution for traffic signals settings. Shortest path algorithms are utilized to regulate the congestion level of the network. Large networks are partitioned into subnetworks to enable the optimization and simulation procedure. Several case studies are analyzed in this thesis to examine the efficiency of each approach and to observe the influence of different factors in the solution quality and computation time of the optimization process.
M.S. in Electrical Engineering, December 2015
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Title: CHIRPLET SIGNAL DECOMPOSITION AND PARAMETER ESTIMATION ALGORITHMS FOR ULTRASONIC SIGNAL ANALYSIS
Creator: Kasaeifard, Alireza
Date: 2012-12-03, 2012-12
Description: In ultrasonic imaging systems, shape, size and orientation of the reflectors and the physical properties of the propagation path govern the...
Show moreIn ultrasonic imaging systems, shape, size and orientation of the reflectors and the physical properties of the propagation path govern the patterns of backscattered echoes. However, the backscattered echoes often interfere with each other due to closed locations, orientations and size of reflectors and may be corrupted by noise. Hence, signal modeling and parameter estimation of the ultrasonic echoes are essential for image analysis, detection, classification and diagnosis. Certain important information like position, shape and size of the reflectors can be represented by chirplet signal parameters. Similarly, in other important application area of signal modeling such as radar, sonar and speech, chirplet signal parameters are also critical. The objective of this study is to analyze the pattern of ultrasonic echoes using chirplet signal decomposition and parameter estimation techniques. Signal processing method for decomposing multiple interfering ultrasonic echoes is a major and challenging problem. The chirplet signal decomposition algorithms designed and analyzed in this investigation are based on the Fractional Fourier Transform (FrFT) and elliptic template matching applied to time-frequency distributions of ultrasonic signals. This study has a broad range of applications of importance in signal detection, estimation, and pattern recognition. Fractional Fourier Transform based Chirplet Signal Decomposition (FrFT-CSD) algorithm is proposed to analyze ultrasonic signals for NDE applications. Particularly, this method is utilized to isolate dominant chirplet echoes for successive steps in signal decomposition and parameter estimation. FrFT rotates the signal with an optimal transform order. The search of optimal transform order is conducted by determining the highest kurtosis value of the signal in the transformed domain. A simulation study reveals xi the relationship among the kurtosis, the transform order of FrFT, and the chirp rate parameter in the simulated ultrasonic echoes. Benchmark and ultrasonic experimental data are used to evaluate the FrFT-CSD algorithm. Signal processing results show that FrFT-CSD not only reconstructs signal successfully, but also characterizes echoes and estimates echo parameters accurately. To accelerate echo estimation algorithm, we present a novel method for estimating the parameters of chirp echo by means of ellipse fitting in the Time-Frequency (TF) domain. Wigner-Ville Distribution (WVD) and Short-Time Fourier Transform (STFT) of chirplets are in the form of concentric ellipses in the TF plane. The elements of ellipse such as long axis, short axis and the slope of the ellipse correspond to the chirplet parameters and this can be used for parameter estimation. To demonstrate the parameter estimation performance of ellipse fitting method, the algorithm is used to decompose an ultrasonic experimental signal consisting of many interfering echoes acquired in nondestructive testing of a steel block. The comparison between the reconstructed signal and the experimental result shows that the decomposition has been successfully performed in the presence of measurement noise and interference from microstructure scattering echoes. The Ellipse Fitting Method (EFM) employs short-time Fourier transform as the main computational load of the algorithm that makes it a good candidate for real-time applications using FFT hardware accelerators. In this study we also present a Field-Programmable Gate-Array (FPGA) implementation that is able to perform chirplet signal decomposition using EFM. The EFM algorithm has been implemented as a system-on-chip consisting hardware architecture and software code on a Xilinx Virtex-5 FPGA. The xii designed hardware architecture is a combination of an embedded Microblaze processor, IP cores, communication buses, and I/Os. The software component represents a portion of the estimation algorithm that runs on the Microblaze processor. The EFM algorithm is used to decompose an ultrasonic experimental signal consisting of many interfering echoes.. The profiling analysis shows the major portion of the execution time (i.e., 94%) is for the FFT computations. By adding and interfacing the FFT IP-core accelerator to Microblaze, the estimation time for each chirp echo is reduced by 85% (i.e. from 550 ms to 82 ms). This reduction in echo estimation is highly desirable and makes the real-time parameteric signal analysis practical.
PH.D in Electrical Engineering, December 2012
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Title: RECRYSTALLIZATION MECHANISM FOR TWO NICKEL BASED SUPERALLOYS
Creator: Balandra, Ombeline
Date: 2016, 2016-05
Description: The demand for enhanced structural performances materials is growing every year. A lot of technological advancements in the sector of...
Show moreThe demand for enhanced structural performances materials is growing every year. A lot of technological advancements in the sector of aerospace or nuclear are in constant need for materials with good mechanical properties and high temperature resistance. The alloys commonly used for these features are Nickel-based superalloys as they exhibit high strength and good resistance to corrosion and oxidation. To improve their mechanical behavior, recent studies have focused on grain refinement methods. Among these methods to obtain the finest grain size distribution, one is particularly advantageous for it low cost and feasibility: severe plastic deformation.In this study, the deformation mechanism of two high performance, low stacking fault energy nickel-based alloys are investigated. The first alloy, Monel 400, it is a single FCC phase material. The second one is Inconel 625 wich has a two-phase (γ and γ’) microstructure. During hot deformation, the γ’ precipitate may be present in the γ phase and above a certain solvus temperature, the γ phase exists in the material. The restoration mechanism for FCC crystals is well known, and particular attention was given in this report to the recrystallization response and flow behavior of Inconel 625 for sub-solvus temperatures. In the introduction a brief review of the current state of literature on the deformation response of Nickel-based superalloys is provided. Samples were compressed under various temperatures and strain rate conditions using a Gleeble-3500 thermo-mechanical simulator and flow stress curves were extracted. To characterize both qualitatively and quantitatively the deformation, samples were then analyzed using standard microscopy, scanning electron microscopy and electron backscatter diffraction analysis. The resulting images and maps combined with flow stress curves have lead to the formulation of constitutive models of the recrystallization process using three parameters, the stress, grain size and recrystallized volume fraction.The data shows that deformation is first accommodated through dynamic recovery with the formation of sub-grains structures. Then, after the experimental strain reaches a critical value, recrystallized grains form within the microstructure. EBSD analysis show a trend for new recrystallized grain to grow under certain conditions. Results show a trend of increasing the grain size with increasing the strain and decreasing the Zener-Hollomon parameter and an increasing recrystallized volume fraction with increasing the strain and Zener-Hollomon parameter.
M.S. in Material, Mechanical and Aerospace Engineering, May 2016
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Title: ANALYSIS OF TRANSPORT TOPOLOGY IN THE LEFT VENTRICLE UNDER HEALTHY AND DISEASED STATES
Creator: Hendabadi, Sahar
Date: 2013, 2013-12
Description: There is evidence that under healthy conditions the vortical nature of blood in the LV optimizes pumping, yet precise characterization of...
Show moreThere is evidence that under healthy conditions the vortical nature of blood in the LV optimizes pumping, yet precise characterization of transport in the LV has been lacking. Because the ventricle is not completely emptied during ejection, blood entering through the mitral valve also interacts with residual ow from preceding cycles. The clinical and physiological consequences of these uid dynamics and interactions remain poorly understood in both healthy and diseased hearts. Simulation and imaging studies have aimed to understand the role of intraventricular ow dynamics to facilitate lling, increase ejection e ciency, and avoid blood stasis inside the ventricular chamber. Moreover, these three aspects may be of key importance in patients with heart disease, and most prevalently dilated cardiomyopathy (DCM). In this thesis, we used in vivo measurement of ow in healthy and diseased hearts. A novel processing of Doppler-echocardiography data was performed on patients with DCM and healthy volunteers. Bi-directional velocity eld maps in the apical long axis were obtained and used to perform Lagrangian analysis of transport inside the LV. Lagrangian coherent structures (LCSs) were shown to reveal the boundaries of blood injected and ejected from the heart over multiple beats. These boundaries were used to quantify stasis in the LV, which has potential clinical importance for diagnosing pumping de ciency and thrombosis risk. Indeed, we show that repelling LCSs, in addition to revealing a schematic of the transport topology, also identify structures in the ow that may potentially in uence platelet activation, which we demonstrate on an idealized stenosis model for simplicity. The LCS framework also enabled improved characterization of LV vortices, which had previously received much attention using Eulerian characterizations. The Lagrangian framework presented here uncovered well-de ned boundaries to both E-wave and A-wave lling vortices, which have not been previously quanti ed. To validate the utility xii of the planar ow approximation imposed by Doppler-echocardiography in enabling the dominant transport processes to be characterized, two di erent sets of 3D phase contrast magnetic resonance imaging (PCMRI) data were used to compare 3D ow analysis results with results derived from 2D projection of data in the long-axis. The validation results indicated that the main transport structures were preserved in 2D projections, especially during the ejection phase. Analysis of LV ow topology was also performed in patients undergoing cardiac resynchronization therapy (CRT). The results of this study can contribute to the optimization of AV delays in these patients by taking the LV transport into account. xiii
PH.D in Mechanical Engineering, December 2013
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Title: YAMUNA RIVER CITY: SUSTAINABLE NEW CITY NEW DELHI, INDIA
Creator: Aggarwal, Sakshi
Date: 2013, 2013-07
Description: The aim of this thesis is to design a sustainable city prototype with a new approach for a 100,000 residents in Delhi , India .This will give...
Show moreThe aim of this thesis is to design a sustainable city prototype with a new approach for a 100,000 residents in Delhi , India .This will give the ‘Delhiites‘ ( as we love to call ourselves ) a chance to live on the water body in a sustainable environment. To create this sustainable environment, the first challenge was to understand the site conditions, followed with the issues on the site, concept of developing new cities, reinforcing old sustainable technologies, and merging with new technologies for a better environmental, social and economic balance. Being on a flood plain, Delhi’s beautiful Yamuna river bed, was never built before, may be ignoring the fact that structure engineering has done some marvels in the past. Thus, I took up this challenge of building a city prototype here. It is hopeful that the design, ideas and process could also be a framework to be applied on other undeveloped land for new cities particularly in India and helps us to provide the solution for any foreseen problems in city development beforehand.
M.S. in Architecture, July 2013
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Title: THE BUSINESS CYCLE, FORECAST HORIZONS AND STOCK RETURN PREDICTABILITY
Creator: Irons, Robert
Date: 2012-12-04, 2012-12
Description: This paper investigates the impact of the business cycle when forecasting equity returns over different forecast horizons. Weigand and Irons ...
Show moreThis paper investigates the impact of the business cycle when forecasting equity returns over different forecast horizons. Weigand and Irons [2007] show that relative valuation matters when forecasting long-term returns to the market, a conclusion that is verified in this study with reference to the period 1934-1949. This study reveals that the business cycle matters when forecasting short-term (one year or less) market returns, over the entire period of study (1934-1999). An econometric issue first noted in Weigand and Irons [2008] is verified and pinpointed more precisely in time, to the year 1950. The market earnings yield (the inverse of the market P/E ratio), one of the foremost predictors of future market returns, is shown to be ineffective in forecasting returns over any forecast horizon in the second half of the 20th century. This result is further evidence of the impact of investors' belief in the Fed Model, which equates the yields on bonds to the returns on stocks. The term spread of interest rates, one of the business cycle proxies used in this paper, is shown to have a significant impact when forecasting market returns over any horizon during the period 1950-1999, which is consistent with the Fed Model.
PH.D in Management Science, December 2012
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Title: ASSESSING THE DIFFERENCES BETWEEN TEACHER AND CHILD PERCEPTIONS OF SOCIAL SKILLS
Creator: Roberts, Christina M.
Date: 2012-11-26, 2012-12
Description: This study examined the effects of group membership on the perception of social skills by comparing discrepancies between self-ratings and...
Show moreThis study examined the effects of group membership on the perception of social skills by comparing discrepancies between self-ratings and teacher-ratings of social skills. Given that differences between groups are typically controlled for, profile comparisons of this kind are scarce in the current literature. In this study, social skills of children in third, fourth, and fifth grades (N=108) were rated both by the children and by their teachers. Results from the analysis of the data, using discrepancy scores on the Social Skills Inventory System (SSIS), suggest that significant group differences only exist between ratings of Latino and African American children and ratings by their teachers. Additionally, no significant differences were observed when examining groups by gender, Piagetian stage, and by child age. Implications indicate that ethnicity affects teacher perception of social skills.
M.S. in Psychology, December 2012
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Title: HYBRID ELECTROSTATIC AND MICRO-STRUCTURED ADHESIVES FOR ROBOTIC APPLICATIONS
Creator: Ruffatto, Donald F., Iii
Date: 2015, 2015-07
Description: Current adhesives and gripping mechanisms used in many robotics applica- tions function on very speci c surface types or at de ned attachment...
Show moreCurrent adhesives and gripping mechanisms used in many robotics applica- tions function on very speci c surface types or at de ned attachment locations. A controllable, i.e. ON-OFF, adhesive mechanism that can operate on a wide range of surfaces would be very advantageous. Such a device would have applications ranging from robotic gripping and climbing to satellite docking and inspection/service mis- sions. The main goal of the research presented here was to create such an attachment mechanism through the use of a new hybrid adhesive technology. The newly devel- oped adhesive technology is a hybridization of electrostatic and micro-structured dry adhesion. The result provides enhanced robustness and utility, particularly on rough surfaces. There were challenges not only in the integration of these two adhesive elements but also with its application in a complete gripping mechanism. Electrostatic and directional dry adhesives were both individually investigated. The electrode geometry for an electrostatic adhesive was optimized for maximum ad- hesion force using nite element analysis software. Optimization results were then veri ed through experimental testing. New manufacturing techniques were also de- veloped for electrostatic adhesives that utilized a metalized mesh embedded in a sili- cone polymer and Kapton lm based construction, greatly improving adhesion. The micro-structured dry adhesive used was provided by Dr. Parness, from the NASA Jet Propulsion Lab (JPL), and consists of an array of vertical stalks with an angled front face, referred to as micro-wedges. The hybrid electrostatic dry adhesive (EDA) was created by fabricating the electrostatic adhesive directly on top of a dry adhesive mold. This process created an array of dry adhesive micro-wedges directly on the surface of the electrostatic adhesive. In operation the electrostatic adhesive provides a normal force which serves to pull the dry adhesive into the surface substrate. With greater surface contact more of the dry adhesive is able to engage, bring the electro-static adhesive even closer to the surface and increasing its e ectiveness. Therefore, the combination of these two technologies creates a positive feedback cycle whose whole is often greater than the sum of its parts. An interface mechanism is needed to transmit applied loads from a rigid struc- ture to the exiable adhesive while still maintaining its conformability. This is es- pecially important for strong adhesion on rough surfaces, such as tile and drywall. Di erent concepts such as a structured brillar hierarchy and a uid- lled backing pouch have been explored. Additionally, nite element analysis was used to evaluate di erent fribrillar shapes and geometry for the structured hierarchy. The goal was to equalize the load distribution across the adhesive while still maintaining surface compliance. A gripper mechanism was also created which used a servo for actuation and three rigid tiles with a directional dry adhesive. It was tested on a perching Micro Air Vehicle (MAV) as well as in the RoboDome facility at NASA's Jet Propulsion lab to simulate a satellite docking/capture maneuver.
Ph.D. in Mechanical and Aerospace Engineering, July 2015
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Title: BANDWIDTH ENHANCEMENT OF A COMPACT ANTENNA BY PARASITIC ELEMENTS
Creator: Celebi, Adem
Date: 2015, 2015-05
Description: Antenna structures are playing a major role in wireless systems, including communication systems, radars, satellite systems, information...
Show moreAntenna structures are playing a major role in wireless systems, including communication systems, radars, satellite systems, information networks and medical diagnostic systems. In these systems, external antennas are widely used, especially for devices with metallic enclosures. One of the common requirements for the ex- ternal antennas is the need for achieving small dimension while keeping the antenna performance optimized. In this respect, electrically small antennas (ESAs) are em- ployed. Realizing the design requirements of an ESA has been a challenge for antenna designers because some of the parameters such as large bandwidth and reasonably high input impedance are in conflict with the small antenna dimensions. A compact antenna with parasitic elements for bandwidth enhancement is proposed to address these issues for use with mobile devices. Loading the known antenna topologies with other structures could improve the design parameters such as gain, bandwidth, impedance, and beamwidth for antenna topologies which are impossible to achieve with the conventional antennas. In this respect, a parasitic element with a smaller scale is placed within the structure to obtain a second resonance close to the main antennas resonance for an increased bandwidth without increasing the overall dimen- sions of the antenna. This composite antenna is expected to have relatively high input impedances for each of the resonances, thus minimizing the need for an input matching network. A review of related prior work of antenna structures is presented to gain insight into the recent developments and methods in the field. The mini- mum quality factor (Q) and maximum gain of the ESA designs and their theoretical Antenna structures are playing a major role in wireless systems, including communication systems, radars, satellite systems, information networks and medical diagnostic systems. In these systems, external antennas are widely used, especially for devices with metallic enclosures. One of the common requirements for the ex- ternal antennas is the need for achieving small dimension while keeping the antenna performance optimized. In this respect, electrically small antennas (ESAs) are em- ployed. Realizing the design requirements of an ESA has been a challenge for antenna designers because some of the parameters such as large bandwidth and reasonably high input impedance are in conflict with the small antenna dimensions. A compact antenna with parasitic elements for bandwidth enhancement is proposed to address these issues for use with mobile devices. Loading the known antenna topologies with other structures could improve the design parameters such as gain, bandwidth, impedance, and beamwidth for antenna topologies which are impossible to achieve with the conventional antennas. In this respect, a parasitic element with a smaller scale is placed within the structure to obtain a second resonance close to the main antennas resonance for an increased bandwidth without increasing the overall dimen- sions of the antenna. This composite antenna is expected to have relatively high input impedances for each of the resonances, thus minimizing the need for an input matching network. A review of related prior work of antenna structures is presented to gain insight into the recent developments and methods in the field. The mini- mum quality factor (Q) and maximum gain of the ESA designs and their theoretical limitations are then discussed. The features of the antenna designs discussed in the review are used as foundation of the developed antenna structures. The properties and a fabrication method of the proposed antenna are then discussed. A commer- cially available software package based on finite element method is employed to aid in the antenna design. Several antenna prototypes are constructed to verify the design and the accuracy of the simulations. The prototypes are then tested using network analyzers and an RF anechoic chamber with the aim of characterizing the antenna performance in terms of antenna bandwidth and input impedance.
Ph.D. in Electrical and Computer 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: IDENTIFY AND IMPROVE OBSTACLE AVOIDANCE CAPABILITY OF UNMANNED GROUND VEHICLE
Creator: Nie, Chenghui
Date: 2015, 2015-05
Description: An Unmanned Ground Vehicle (UGV), incorporating a high level of obstacle avoidance capability, benefits from field operations. Such a UGV...
Show moreAn Unmanned Ground Vehicle (UGV), incorporating a high level of obstacle avoidance capability, benefits from field operations. Such a UGV would be better able to travel at a high average speed to quickly finish tasks, as well as quickly alter its trajectory to avoid getting into hostile situation. However, avoiding obstacles at high speed is challenging, since the danger of collisions with obstacle is increased with vehicle speed. This thesis developed novel metrics to mathematically identify the obstacle avoidance capability of ground vehicles. The theory is applied to demonstrate the characteristics of the obstacle avoidance capability of generalized rigid bodies and three types of wheeled ground vehicles: Ackermann steered, differential steered and omni-directional vehicle. The design guidelines are provided in the final chapters to improve obstacle avoidance capabilities of these three types of wheeled ground vehicles. I demonstrated in this thesis that the Ackermann steered vehicle's obstacle avoidance capability is related to the location of its center of mass. I utilized the obstacle avoidance theory to create a novel Variable Inertial Vehicle (VIV), an unmanned ground vehicle with a capability to control the location of its center of mass during locotion. Experimental results are presented to demonstrate the improved obstacle avoidance capability at the end. This thesis also experimental evaluates the characteristics of the obstacle avoidance capability of an omni-directional unmanned ground vehicle. This omnidirectional vehicle is comprised of four independent differential steered units, Active Split Offset Caster (ASOC). Both the characteristics of the vehicle system and ASOC kinematics are demonstrated. Experimental results are presented at the end to validate its distinct obstacle avoidance capability in challenging outdoor terrains.
Ph.D. in Mechanical and Aerospace Engineering, May 2015
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Title: INVESTIGATING DIRECTED EVOLUTION AND GENETIC ENGINEERING WITH VITREOSCILLA HEMOGLOBIN TO PRODUCE CULTURES FOR LOW AERATION BIOLOGICAL WASTEWATER TREATMENT
Creator: Kunkel, Stephanie
Date: 2014, 2014-07
Description: The dominance of hemoglobin (Hb)-expressing bacteria in biological wastewater treatment systems could improve oxygen utilization under low...
Show moreThe dominance of hemoglobin (Hb)-expressing bacteria in biological wastewater treatment systems could improve oxygen utilization under low dissolved oxygen (DO) conditions. Hb-proteins are versatile molecules that have several biological functions. Here, Nitrosomonas europaea has been transformed with various plasmids; of particular interest is a recombinant plasmid bearing the constitutive Amo1 promoter and the gene (vgb) encoding the hemoglobin from the bacterium Vitreoscilla. Expression of VHb was assayed using various visible spectral methods, and VHb production seen in this recombinant strain. There were several positive effects on N. europaea metabolism related to VHb expression that were seen, specifically the ability of cultures to convert ammonia to nitrite at a slightly higher rate as well as higher specific oxygen uptake rates (SOUR) at both high (near saturation, 7 mg O2/ L) and low (< 2 mg O2/L) dissolved oxygen (DO) conditions. In parallel to this, two activated sludge cultures from the same source were cultivated using synthetic wastewater seeded with activated sludge from the same source and were operated at high DO (near saturation) and low DO (0.25 mg O2/L) concentrations for 370 days. There were significant changes in the bacterial species and phyla present in each of the cultures at various time points during the 370 day operational period. In the low DO culture, over time, there was a much greater expression of single domain and truncated Hbs which may enhance utilization and delivery of oxygen to various enzymes as well as to the respiratory chain. A larger increase in heme b was also observed which coincides with this observation. By the end of the acclimation period, the SOUR values were about 30% greater in the low DO culture compared to the high DO culture. This indicated the successful adaption of the low DO culture to respire more efficiently and eventually outperform the high DO culture.
Ph.D. in Biology, July 2014
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Title: COMPARATIVE ANALYSIS OF GROWTH KINETICS OF LISTERIA MONOCYTOGENES LINEAGES I AND II IN CHOPPED RED CABBAGE AND CUCUMBER USING PRIDICTIVE MODELING
Creator: Qi, Yan
Date: 2015, 2015-07
Description: Recently, outbreaks oflisteriosis assoc iated with cons umption of contaminated fresh produce by Listeria monocytogenes have increased....
Show moreRecently, outbreaks oflisteriosis assoc iated with cons umption of contaminated fresh produce by Listeria monocytogenes have increased. However, we know little about L. monocytogenes persistence and growth in fresh-cut produce items . The two main human foodbome outbreak lineages ofL. monocytogenes are LI and LB. Strains in LI (including serotypes 1/2b and 4b) are most likely to be isolated from human with listeriosis and Strains in LII (including serotypes 1/2a and 1/2c) are most likely to be isolated from food products and the natural environment. In order to determine the comparative survival and growth kinetics of these two lineages in chopped red cabbage and cucumber, samples of produce were chopped into 100 grams quantities and inoculated with 104 CFU/g of a cocktail of either LI (F2365, H7858, R2-502) or LII (LS814, JI-I 01, J1-067) antibiotic resistant strains. Samples were stored in deli-style containers at 5 or 10°C for 14 days, or 25°C for 7 days. At various intervals, samples were stomached and plated onto PCA with appropriate antibiotics. Data were modeled using DMFit from ComBase and statistical analyses were performed with GraphPad InStat. A p -value less than 0.05 was considered significant. The res ults for the grow th rates ((logIOCFU/g)/h) of the L. monocytogenes LI cocktail in red cabbage were significantly higher at 5°C (0.006±0.003), 10°C (0.017±0.004), and 25°C (0.051±0.017) than the LII cocktail ; and L. monocytogenes LI cocktail in cucumber were significantly lower at 25°C (0.098±0.00 84). Secondary models using the Ratkowsky equation presented r 2 values of 0.9866 for LI in red cabbage whereas presenting / values of 0.9998 and 0.9997 for LI and LII in cucumber, respectively. No significant difference between two lineages was seen in red cabbage and cucumber during ambient temperature display. Finally, the behavior of L. monocy togenes LI and LII on red cabbage and cucumber after potential consumer temperature abuse was determined. In red cabbage, LI grew steadily. However, the growth of L1I in red cabbage was more dynamic. In cucumber, there was no significant difference between LI and LII. The result s from this study will aid in comparing the growth and survival kinetics of Ll and L1l of L. monocytogenes and will provide guidance to both customers and the food industry.
M.S. in Food Safety and Technology, July 2015
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Title: REGULATION OF THE CELL DEATH SIGNALING PATHWAY IN ANDROGEN-INDEPENDENT PROSTATE CANCER CELLS
Creator: Lin, Yuting
Date: 2012-04-16, 2012-05
Description: Prostate cancer is the 2nd leading cause of cancer death in American men, mainly due to therapy-resistance in the advanced stage, androgen...
Show moreProstate cancer is the 2nd leading cause of cancer death in American men, mainly due to therapy-resistance in the advanced stage, androgen-independent prostate cancer (AIPCa). One major defect is that the cancer cells are insensitive to apoptosis induced by androgen ablation, chemotherapy or radiation therapy. However, the underline molecular mechanism still remains unclear. In this thesis, we focused on cell death signaling regulation in the development of AIPCa cells. We first show that up-regulation of Bcl-2, an anti-apoptotic oncogene, is required for the transition of prostate cancer cells from an androgen-dependent to an androgen-independent growth stage. Knockdown Bcl-2 impairs the transition process and blocks androgen-independent prostate tumor formation in vivo. Second, we show that Androgen-receptor (AR), which is generally considered as a survival factor in prostate cancer, promotes stress-induced apoptosis in AIPCa cells. AR promotes apoptosis through augmenting the mitochondrial translocation of Bax, a pro-death family member of Bcl-2. Finally, we show that AR can execute both pro-death and pro-survival events in same AIPCa cells. The AR pro-survival role is transcription-dependent, while its pro-death activity is transcription-independent. Interestingly, the AR exerts both functions through regulating p21 and JNK signaling pathways. These findings will help us to understand the dynamic survival signaling process in the development and progression of AIPCa. The key molecules identified here also provides potential therapeutic targets for the treatment of prostate cancer.
Ph.D. in Biology, May 2012
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Title: GALLIUM NITRIDE NANOSTRUCTURED POWER SEMICONDUCTOR DEVICES
Creator: Sabui, Gourab
Date: 2017, 2017-05
Description: Gallium nitride (GaN) has emerged as a promising material for development of power semiconductor devices owing to its superior material...
Show moreGallium nitride (GaN) has emerged as a promising material for development of power semiconductor devices owing to its superior material characteristics. Fabricated GaN power devices have started to outperform its silicon (Si) counterpart with low conduction and switching losses and holds the key to extremely low-loss and high efficiency power delivery circuits of the future. However, GaN power devices have been plagued with several inherent drawbacks preventing an ubiquitous adoption of GaN as the material of choice for power switches. The most critical trade-o↵ has been the choice of substrate for the growth of GaN epitaxy: a high performance, high-cost native substrate or a low-cost, non-native substrate with reliability issues. In order for GaN to thrive as a superior successor to Si, a low cost, high performance epitaxy with improved reliability is expected moving forward. A novel nanostructured approach to GaN power devices is proposed in this dissertation. The nano-GaN power devices theoretically has the potential to bypass the reliability concerns associated with a non-native substrate but still deliver comparable performance. A comprehensive model is proposed for TCAD modeling of bulk GaN power devices to accurately model the nano-GaN devices. Through extensive modeling and simulations, design guidelines for Schottky barrier diodes and field effect transistors based on the nano-GaN concept is laid out to extract the best performance out of this architecture. Dielectric and semiconductor interaction is also exploited to push these devices to perform beyond the unipolar material limit of GaN. The simulated and fabricated nano-GaN power devices show the potential to deliver equivalent or superior performance to present state of the art GaN devices but with improved reliability, ruggedness and low cost.
Ph.D. in Electrical Engineering, May 2017
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Title: INVESTIGATION AND MODELING OF PRESSURE DEPENDENT YIELD BEHAVIOR OF 3D STOCHASTIC AND PERIODIC FOAMS
Creator: Ayyagari Venkata S, Ravi Sastri
Date: 2013, 2013-07
Description: With growing potential of cellular solids in a multitude of diverse engineering applications including but not limited to automotive,...
Show moreWith growing potential of cellular solids in a multitude of diverse engineering applications including but not limited to automotive, aerospace, naval and biomed- ical industries as lightweight alternatives and space lling cores in sandwich struc- tures, need for predictive yield/failure criteria for these load bearing members under multiaxial stress states becomes critical. Although there exist several yield criteria proposed in the literature for highly porous solid foams, they are all phenomenolog- ical in nature, rely on relatively long list of model parameters that require di cult experimentation not readily available to end user, and none of them can handle the anisotropy observed in the majority of commercially available solid foams. Further, it is by now well established that, unlike commonly used engineering bulk solids, the yield behavior of highly porous solid foams is signi cantly in uenced by the hydro- static component of stress. In majority of phenomenological yield criteria proposed for solid foams this dependence is expressed by a quadratic pressure term. The scope of this study is quite comprehensive in the sense that it integrates analytical and computational investigation of yield behavior in solid foams along with extensive validation by recent experimental results produced in our lab. Present study proposes a physics based approach by hypothesizing that the yielding of stochastic foams is governed by the total elastic strain energy density, which leads to an energy based yield criterion for transversely isotropic foams and also provides a physical basis for the quadratic pressure dependence commonly adopted in existing phenomenolog- ical models. An added bene t of the analytical framework proposed in this work is that it introduces new scalar measures of stress and strain, which are referred to as characteristic stress and characteristic strain, that function in an analogous way to e ective (von Mises) stress and strain commonly used in analyzing the yield and post- yield behavior of bulk metals. Besides accommodating anisotropy, this energy-based xii yield criterion renders a unique advantage by relying only on the elastic properties and uniaxial yield strengths of the material, which makes the proposed yield criterion extremely practical for end user. Results from experimental data obtained from multiaxial testing of Divinycell H100 and H130 foams (Sha q, 2009; Ehaab, 2011) as well as a series of extensive com- putational simulations performed in this study on: a) periodic Kelvin foam models (both isotropic and transversely isotropic) of varying relative densities, b) stochastic Voronoi foams (both isotropic and transversely isotropic), point out to an additional linear pressure dependence in the yield behavior of solid foams, from a load-sharing viewpoint. This dependence is observed to be more pronounced at lower relative den- sities. A simple quantitative technique which is based on the partition of elastic strain energy into bending and stretch components is used to identify the distribution of deformation modes at microstructural level, along with its in uence on load sharing as a function of stress path. Furthermore, a plasticity model that incorporates a ow rule and hardening law are presented which allows the analysis of inelastic deforma- tions in solid foams in a continuum framework. Such models facilitate development of user de ned material model (UMAT) that allow evaluating the performance of proposed yield criterion under complex loading scenarios, such as indentation and punch loading.
PH.D in Mechanical and Aerospace Engineering, July 2013
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Title: ENHANCEMENT OF DESULFURIZATION BY DIRECTED EVOLUTION UTILIZING THE SULPEPTIDE AND CHLORAMPHENICOL RESISTANCE GENES
Creator: Yu, Qingfei
Date: 2013, 2013-12
Description: With the increasing demand of upgrading the quality of petroleum, optimizing the efficiency of biodesulfurization (BDS) is necessary. R....
Show moreWith the increasing demand of upgrading the quality of petroleum, optimizing the efficiency of biodesulfurization (BDS) is necessary. R. erythropolis 5F [pRESX dszABC] encodes the enzymes of the 4S pathway (on the dszABC operon) which catalyze the conversion of dibenzothiophene (DBT) to hydroxybiphenyl (2-HBP) plus sulfite. Our research attempts to increase the nutritional requirement of the cell for sulfur and to use selective pressure to obtain improved desulfurization. The genetic engineering strategy involves inserting the sulpeptide 1 (S1) gene, which encodes a sulfur-rich polypeptide, between dszA and dszBC in the dszABC operon to increase sulfur demand and force the strain into a spiral of ever increasing dszABC expression and thus desulfurization ability. Insertion of the chloramphenicol resistance (Cm) gene between dszAS1 and dszBC provides an additional method to select strains with higher desulfurization ability by their increasing resistance to chloramphenicol. We completed directed evolution for 22 passages for all three strains (those containing pRESX dszABC, pRESX dszAS1BC, or pRESX dszAS1CmBC transformed into strain 5F) and measured the desulfurization activity at selected passages. The results show that directed evolution did improve the desulfurization abilities in the first ten passages in the strains expressing dszABC and dszAS1CmBC, but reduced the desulfurization ability in the strain expressing dszAS1BC. For all three strains and all passages tested, the highest desulfurization activity was 83.6 μmol DBT/g DCW/hour in the dszABC bearing strain. Thus, the presence of S1 had a negative effect on the rate of desulfurization. A possible explanation for these results is that mutations occurring during the selection process enhance the efficiency of sulfur utilization and S1 alone can thus not force the strains to improve desulfurization.
M.S. in Biology, December 2013
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Title: THE EFFECT OF SURGICAL DECISION MAKING ON QUALITY OF LIFE IN ADOLESCENTS WITH CRANIOFACIAL CONDITIONS
Creator: Sokolowski Ruta, Caroline M.
Date: 2011-07, 2011-07
Description: Previous research concerning the delivery of medical services to adolescents, specifically the extent to which young people are involved in...
Show morePrevious research concerning the delivery of medical services to adolescents, specifically the extent to which young people are involved in the planning of their care, is lacking. This study investigated the importance of the decision-making process in adolescents with craniofacial conditions (CFCs) and whether their involvement in surgical decision-making has an effect on their perceived surgical outcome. Additionally, the study explored whether resilience factors such as positive self-concept, freedom from depression, coping abilities, and positive views of CFCs positively influence surgical outcome. Results demonstrated that coping abilities and positive views of CFCs predicted positive surgical outcome. Active participation in the decision-making process also predicted positive surgical outcome, though the effect size was trivial. Lastly, adolescent psychological health did not have an influence on surgical outcome. Limitations and areas for future research are discussed.
M.S. in Psychology, July 2011
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