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Title: YIELD BEHAVIOR OF SOLID FOAMS UNDER MULTIAXIAL STATES OF STRESS
Creator: Ehaab, Mohammad
Date: 2011-12-14, 2011-12
Description: Growing use of solid foams as core material in load bearing composite sandwich structures requires the development as well as validation of...
Show moreGrowing use of solid foams as core material in load bearing composite sandwich structures requires the development as well as validation of predictive yield criteria for these extremely porous and, hence, lightweight engineering materials. It has been well established that solid foams, unlike the majority of bulk materials, have a pressure dependent yield behavior. This makes the validation of various yield criteria proposed in literature a challenging task because of the need for complex biaxial and triaxial experiments, which is the main reason for both the scarcity of data and the lack of predictive power in existing models. Although there have been a limited number of studies recently in literature to generate data beyond uniaxial compression and tension experiments by introducing new loading apparatuses such as Arcan apparatus and universal biaxial testing device (UBTD), they have been limited to probe shear-compression and shear-tension states of stresses without independent control of the shear component. Therefore, the data extracted from these experiments cover only a small fraction of stress space. An example of a truly biaxial testing machine with independent load control is biaxial crushing machine (BICURMA) which, however, is restricted to only compressive loads. One must recognize that biaxial testing, even with full tension/compression control, doesn’t expand the fraction of yield surface that can be probed in any significant proportion beyond shear/compression techniques. Extremely pressure dependent mechanical behavior of solid foams requires triaxial experiments for a full description of their yield surface, hence the challenge. This work addresses this challenge by using a multiaxial testing apparatus (MATA) developed at IIT to comprehensively probe the yield surface of Divinycell H100 and H130 PVC foams through uniaxial, biaxial and triaxial experiments where loads are independently controlled in each orthogonal direction. Data reduction relies on new scalar measures of characteristic stress and strain proposed by Ayyagari and Vural (2011), and yield data is compared with their newly developed pressure dependent yield criterion. Experimental results reveal that solid foams exhibit both quadratic and linear pressure dependence. Although quadratic dependence on pressure has been previously shown in literature with a limited number of experimental yield data, extensive yield data of the current study suggests a significant linear dependence as well. The final portion of this study outlines a set of new micro-scale experiments designed to test mechanical behavior of individual ligaments that make up Duocell aluminum foam, and some preliminary results.
M.S. in Mechanical, Materials, and Aerospace Engineering, December 2011
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Title: ART ECO, CHONGMING ISLAND, CHINA
Creator: Thadhani, Monika
Date: 2011-04-26, 2011-05
Description: Architecture has always been the result of the delicate balance between art and science & form and function. This thesis project simply...
Show moreArchitecture has always been the result of the delicate balance between art and science & form and function. This thesis project simply embraces this belief by creating a museum and its distinctive form collectively with its sustainable design and environmentally conscious program and operation. Art Eco Museum is an element of prospective sustainable city development on Chongming Island in China. The Museum site is located near Shanghai metropolitan area at the Yangtze River outlet by the East Sea. The Island is an escape from the urban dynamic lifestyle of one of the world's most populated city - Shanghai. Chongming Island is a sanctuary that has 1200 square kilometers of undeveloped land with wildlife, wetlands, agriculture and forest preserves. The Art Eco Museum and its site, designed with a consideration of existing environment and Asian culture, becomes an innovative local and global approach and a model for future energy efficient projects while showcasing Chinese and international art. The museum program creates a culture of sustainability, employing all potential sustainable features to minimize energy use and utilize natural resources in its design and operation. The proposed project is not only a sustainable solution for the museum design but is also an example of the architecture which expression emerges from nature in its symbolic implication, form and function. The use of its organic architectural form insinuates the symbolic object of China - bamboo, and its economic and cultural significance. Bamboo, as a symbol of long life in China, became an inspiration for the project design, with its form and meaning. The Art Eco Museum floor plan layout was arranged according to Bamboo Chinese painting composition. Focusing on design that have lead to positive approaches towards a sustainable future, the exhibition at Art Eco Museum takes a step towards making these ideas a reality for consumers and designers in the current ethical and environmental awareness. The idea of sustainability combines the intelligent use of renewable resources with forward-thinking solutions. Most importantly, museum exhibitions place emphasis on the involvement of the consumer, giving them the tools and the knowledge necessary to understand the general concept of sustainability and its application to everyday life. The Art Eco Museum project is an example of aesthetically beautiful art form which serves functional purpose of science to remodel the world and peoples lifestyle to make it more perfect for human habitation.
M.S. in Architecture, May 2011
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Title: SMALL MODULAR NUCLEAR REACTORS: LEARNING AND PRODUCTION
Creator: Kotlyarevsky, Arnold
Date: 2013, 2013-07
Description: Small Modular Nuclear Reactors o er a new alternative to carbon based energy sources in the energy market of the near future. Understanding...
Show moreSmall Modular Nuclear Reactors o er a new alternative to carbon based energy sources in the energy market of the near future. Understanding the economic forces driving the industrial manufacturing process is crucial to determining the viability of SMRs. This study is a continuation of research that developed a parametric model and initial production cost estimates for a generic 100MWe SMR integrated reactor vessel. The primary goal of this study was to characterize the learning rates, lot sizes, and optimum production of SMR IRVs using the parametric model and the initial cost estimates. Three separate models were developed based on increasing levels of learning transfer: no learning transfer, partial learning transfer, and full learning transfer. Models with no learning transfer and full learning transfer bounded the values for the learning curve expected for IRV manufacture. A model with a partial transfer of learning yielded production cost estimates of $312.2 million. Production of an SMR IRV based on this model is expected to see a learning rate 95.5%. Using the information from the other two models, the expected learning rate for IRV production is expected to fall between 93.3% and 99.1% Simulations of lot sizes of 1 to 12 were conducted to determine the manufacturing lot size that optimizes the factory setting. An optimum con guration of 5 units per lot was determined to be the minimum. However, the lot size is recommended to be increased to 6 units to withstand the possibility of cancellation. In this con guration, the average unit cost is $262 million, with a learning rate of 98.1%. Another important result indicates that optimum manufacturing outcomes are not necessarily correlated with higher levels of learning. Production in larger lot sizes is bene cial, especially for components that are few in number, like the pressure vessel.
M.S. in Physics, July 2013
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Title: COGNITIVE DEVELOPMENTAL LEVEL AS A MODERATOR OF LANGUAGE SKILLS AND SOCIAL SKILLS AS WELL AS ACADEMIC ACHIEVEMENT AND SOCIAL SKILLS
Creator: Reife, Ilana
Date: 2012-11-13, 2012-12
Description: Past research has provided evidence that social skills are correlated to both academic achievement and language skills. In addition, Piaget’s...
Show morePast research has provided evidence that social skills are correlated to both academic achievement and language skills. In addition, Piaget’s theory asserts that certain cognitive abilities develop independent of learning (both language and academic skills) that occurs in school. The present study examined the impact of cognitive developmental level as a moderator for the relationship between social skills and academic achievement. Cognitive developmental level was measured using conservation tasks. Social skills were measured with the Social Skills Inventory System. Academic achievement was measured by the Woodcock-Johnson Tests of Achievement, Third Edition, Normative Update. This study also assessed cognitive developmental level as a moderator between social skills and language skills. Language skills were measured with the Peabody Picture Vocabulary Test. A hierarchical linear regression yielded results indicating that when controlling for IQ, gender and ethnicity, cognitive developmental level did not moderate relationships between social skills and language and social skills and academic achievement. However, post hoc analyses demonstrated that ethnicity provides a significant amount of the variance and acts as a covariate. This study contributes to the literature by providing evidence that ethnicity significantly impacts teacher ratings of social skills.
M.S. in Psychology, December 2012
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Title: MECHANICAL AND BIOCHEMICAL FACTORS INFLUENCING INITIAL PLATELET ADHESION TO COLLAGEN: IMPORTANT ROLE FOR SLIDING AND ROLLING IN ACCELERATED AGGREGATE FORMATION
Creator: Au, Bonnie
Date: 2015, 2015-05
Description: Injury at the vessel wall leads to exposure of collagen to which platelets initially adhere, grow into aggregates and eventually thrombotic...
Show moreInjury at the vessel wall leads to exposure of collagen to which platelets initially adhere, grow into aggregates and eventually thrombotic masses which can occlude the vessel lumen. This process underlies the disorders of heart attack and stroke. The initial phase of platelet aggregation governs the extent of thrombus formation. We have investigated initial platelet attachment to collagen-coated surfaces under mechanical and biochemical conditions in a parallel plate flow reactor. A simple algorithm has been developed to simulate the effects of platelet sliding/rolling on the surface with respect to the development of surface aggregate formation. Platelets are hypothesized to stop such movement once they collide with a neighboring platelet in their pathway (due to platelet coherence that strengthens the overall adhesive forces due to platelet-platelet bonding). We and others have observed microscopically that platelets will either attach firmly onto the surface, roll and slide or detach completely from the surface. Platelet behavior was investigated for overall adhesion and the translocation dynamics on overall adhesion on temperature, flow conditions, C-reactive protein (CRP), and coffee consumption. Our findings indicate that temperature, shear force, and CRP promote platelet adhesion and the intake of coffee impedes platelet adhesion.
M.S. in Biomedical Engineering, May 2015
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Title: DISTRIBUTION OF CRP/FNR FAMILY TRANSCRIPTION FACTORS IN SELECT BACTERIAL GENOMES
Creator: Yang, Shengning
Date: 2012-05-07, 2012-05
Description: Cyclic adenosine monophosphate (cAMP, cyclic AMP or 3'-5'-cyclic adenosine monophosphate) receptor protein (abbreviated as CRP), also known as...
Show moreCyclic adenosine monophosphate (cAMP, cyclic AMP or 3'-5'-cyclic adenosine monophosphate) receptor protein (abbreviated as CRP), also known as catabolite gene activator protein, is one type of regulatory protein in bacteria. It acts as a secondary messenger in many intracellular pathways, especially the signal transduction by binding cAMP, which allows the protein to bind DNA sequence in the promoters. Fumarate/nitrate reduction transcriptional regulator, in short Fnr, is another signal transduction molecule which transfers from oxygen status to nifL (Nitrogen fixing bacteria L) protein. Both Crp and Fnr can be grouped into a Crp-Fnr family of transcription factors in many bacteria strains. In this study, we identified Crp-Fnr family genes from different bacteria genomes. Using the Crp-Fnr gene sequences we reconstructed phylogenetic trees for 250 select bacterial genomes which contains at least one Crp-Fnr family gene. We also selected representative Escherichia coli and Salmonella enteriaca genomes for phylogenetic analysis. The circular maps for the four select bacterial genus, Listeria, Salmonella, Escherichia and Brucella were created to demonstrate the genomic locations of Crp-Fnr family genes. Our results showed that the location of Crp-Fnr family transcription factor genes are syntenic amongdifferent bacteria bacterial genomes, indicating their early ancestry acquisition prior to the speciation events.
M.S. in Biology, May 2012
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Title: SILICON CARBIDE JFET BASED SOLID STATE CIRCUIT BREAKERS FOR MEDIUM VOLTAGE DC SYSTEMS
Creator: Moradkhani Roshandeh, Aref
Date: 2016, 2016-07
Description: In application areas such as data centers, electric ships and dc microgrids, dc systems are better systems than ac counterparts, however lack...
Show moreIn application areas such as data centers, electric ships and dc microgrids, dc systems are better systems than ac counterparts, however lack of a fast, reliable and cost effective dc circuit breaker is a big obstacle on the way of development and wide usage of these kind of systems. Nowadays since the demand for electric power and especially, access to renewable energy sources such as solar thermal generation which are located in deserts and off-shore wind power, continuously increases the demand and interest in High Voltage Direct Current (HVDC) and Medium Voltage Direct Current (MVDC) systems. In order to accept and rely on such systems, availability of fast and robust circuit breakers is inevitable which makes them one of the key enabling technologies. This thesis introduces a novel design for solid state circuit breakers (SSCB) for MVDC systems. This SSCB is inactive during normal operation and when a fault occurs, by getting power from the fault condition will be triggered on and clear the fault. This SSCB is consisted of a fast startup flyback-forward converter as a gate driver and two normally-on SiC JFETs as the main static switches which share the bus voltage equally during the fault condition. The operation principles of the SSCB are explained and analyzed in details. Moreover, prototypes are built and tested in short circuit tests. As observed in real test and experiments, the circuit breaker prototype can interrupt short circuit fault current up to 150 amperes at a dc bus voltage of 1000 volts within 3 microsecond.
M.S. in Electrical Engineering, July 2016
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Title: Textile Openings
Creator: Carvallo, Maria Paulina
Date: 2011-12-06, 2011-12
Description: A facade may serve many functions throughout the life of a building, but the primary purpose of a building’s facade is to protect the interior...
Show moreA facade may serve many functions throughout the life of a building, but the primary purpose of a building’s facade is to protect the interior of a structure from the outside environment. By examining an element of every facade design, its openings, one may also find solutions to other design and layout questions concerning a building’s interior. Textile facades show potential as new and interesting materials for facade design. However, textile facades must reinvent or adapt standard facade elements such as windows, doors, and other openings within the constraints of the material properties exhibited by textiles. This thesis explores potential facade opening mechanisms, including technical and natural examples. Details of textile facades are considered, including laser cutting of polyester fabrics, textile material properties and tension deformation, and a variety of textile facade designs. Furthermore, a standardized design workflow and process for considering multiple environmental variables present in and around facades, such as solar thermal, day lighting, ventilation, and identity, are discussed and illustrate that the methodology applied herein can be used to predict other applications of textiles.
M.S. in Architecture, December 2011
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Title: ENERGY SAVINGS FOR UAV FLIGHT IN UNSTEADY GUSTING CONDITIONS THROUGH TRAJECTORY OPTIMIZATION
Creator: Grimaud, Lou
Date: 2014, 2014-07
Description: The purpose of this thesis is to show how micro unmanned aerial vehicles can extract energy from periodic wind gusts and how this energy...
Show moreThe purpose of this thesis is to show how micro unmanned aerial vehicles can extract energy from periodic wind gusts and how this energy extraction is a ected by the e ects of unsteady aerodynamics and the spatial structure of the gust component. The trajectory of a small UAV ying through wind gusts is simulated with a two degree of freedom model. The non-dimensional model is set to include vertical and horizontal gusts of varying amplitudes and durations. From this model an optimization routine is performed in order to obtain the minimum gust amplitude needed to obtain a neutral energy trajectory. With these results, it is shown that neutral energy ight is possible through gusts speeds of only 10 to 30% of the ying speed of the aircraft. Analysis of the results shows that the lift coe cient has to be changed very rapidly in order to perform these maneuvers in short duration gusts. Moreover high lift values are often required. To achieve this kind of rapid change in the lift and drag forces, fast variations of the angle of attack are needed. The high lift values also require high angles of attack that are likely to cause separation of the ow over the airfoil. These fast variations at high angle of attack are shown to cause unsteady non linear aerodynamic responses. Traditional CFD simulations are far too computationally expensive to be implemented into the optimization routine. To solve this issue a low order model based on a paper by Goman and Khrabrov [7] (GK) is developed and validated against experimental results. This model produces accurate predictions of the lift and drag coe cients for a wide range of angles of attack and for di erent type of pitch inputs. With this GK model the in uences of the unsteady aerodynamics on the energy extraction problem are highlighted. The main di erence with quasi-steady aerodynamics model was found to be for gusts at a reduced frequency (k = cf u ) higher than 0.07. Around these values the potential performance is improved by introducing the unsteady model. The trajectories obtained include more violent changes in angle of attack in order to take full advantage of the unsteady e ects.
M.S. in Mechanical, Materials, and Aerospace Engineering, July 2014
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Title: NEW SUSTAINABLE CITY IN MACEDONIA
Creator: Dubrovski, Filip
Date: 2012-11-14, 2012-12
Description: Blessed with the unique power of limited understanding, for centuries human supremacy stood as the universal rule for success and progress....
Show moreBlessed with the unique power of limited understanding, for centuries human supremacy stood as the universal rule for success and progress. With this organized human dominance, present humankind challenged the once unapproachable frontiers of the planet climate equilibrium. For some it is Mother Nature’s perpetual behavior, for others the point of self-destruction. With only a minimum effort given to understand its power and relevance, the human ignorance continued to consume the values of commodity and comfort to achieve an illusion of happiness and self-achievement. Until about five years ago, this illusion created the world’s greatest financial crisis that until today still has no resolution. Addressing the present environmental, social and economic issues by designing a sustainable city becomes a daunting challenge. Given the global unfavorable urban conditions, it is somewhat difficult to understand how the city, man greatest achievement, can also be comprehended as a redemption. Nevertheless, the only certainty of the evolution pattern of civilization is that global population increases will additionally worsens these conditions. Unlike in the past centuries when population increases favored the rich and well established, these patterns now occur in rural regions of undeveloped societies that begin to grow swiftly but without the infrastructure to meet the demand. Additionally disadvantaging are the patterns of intensive sprawl of the mega metropolis which are now captives of the amplifying cost of energy and the congestion of transportation. Therefore, it is an imperative to visualize the New City with its predetermined scale as the most efficient sustainable smart tool to mitigate the xi consequences of these undesirable patterns that are causing social and environmental destruction. The project for a New Sustainable City in Macedonia is an approach that envisions multidisciplinary contributions to society, environment and the economy. Its purpose is to present the best example of a new civilized relation between natural and artificial environment. The design implements values of the walkable and community based transportation methods, multiple socially interactive public squares and elevated residence living. It aims to protect the natural environment and mitigate ecological threats due to climate changes.
M.S. in Architecture, December 2012
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Title: PROTOTYPE OF SUSTAINABLE NEW CITY IN CHILE
Creator: Hernandez Gomez, Soledad Macarena
Date: 2012-11-20, 2012-12
Description: In an era of global climate change and rapid urbanization, it is necessary to change the way of cities have been developed. Cities need a new...
Show moreIn an era of global climate change and rapid urbanization, it is necessary to change the way of cities have been developed. Cities need a new vision and a new strategy to reduce their impact on the environment. Therefore, it is essential to research about how to design sustainable cities, which are the main characteristics of a sustainable urban design, and how it is possible to combine all these factors in a sustainable way to develop a city which reduces impact in the ecosystem and creates a better quality of life as a place to live. For these reasons, one of the main objectives of this thesis is to develop a prototype of a sustainable new city based on the sustainable city principles, and also to understand the social, economic and environmental context where the city is located. In this proposal, the new city is located in the extreme South of Chile to replace a previous city that was destroyed by a volcanic eruption. Therefore, this new city - New Chaiten- is an opportunity in the region to build a city which represents a new vision of sustainable urban development which promotes a balance between the social and economic needs of the community and environmental conservation. Furthermore, it creates an enjoyable urban environment with a high quality of life while reducing energy consumption.
M.S. in Architecture, December 2012
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Title: MODELING AND PERFORMANCE ANALYSIS OF DISTRIBUTED COMPUTER NETWORKS WITH DIFFERENTIATED SERVICES
Creator: Monsef, Ehsan
Date: 2015, 2015-07
Description: The rapid growth of data usage in wired and wireless networks has witnessed an increase in diversity of user tra c in the last few decades. A...
Show moreThe rapid growth of data usage in wired and wireless networks has witnessed an increase in diversity of user tra c in the last few decades. A network with di eren- tiated services guarantees the provision of Quality of service(QoS) for di erent tra c classes by incorporating various class-based scheduling disciplines. Recently, there has been interest in the study of network performance modeling in networks with di erentiated services. In particular, the performance modeling of di erentiated ser- vice networks in distributed architectures has attracted several network communities. The heterogeneity of user tra c can have major impact on the overall performance of resource allocation problems in computer networks. This work aims at shedding light on the performance modeling of distributed wired and wireless environments with di erentiated services. We study the performance of priority-based distributed schemes for several important network applications: (i) network routing(load balanc- ing) in wired network (ii) network selection in wireless environment (iii) scheduling in Body Area Networks and (vi) Interference mitigation scheme for Wireless Body Area Networks. We will utilize Game-theoretic models to model the interaction between network entities and evaluate the system performance analytically and empirically. Our main objective is to investigate the degree in which various service di erentiation mechanisms have impact on the overall performance of distributed networks. We an- alyze several important equilibria properties such as existence, convergence time, and ine ciency for the studied network scenarios. Extensive simulations are conducted to empirically evaluate our game-theoretic analysis for di erent network applications. First, we study a network of parallel links where each link incorporates General Processor Sharing scheduling mechanism. Using the non-cooperative game model, we investigate the existence and uniqueness of equilibrium points. We study the e ciency of equilibria by deriving an upper bound on the Price of Anarchy (PoA). Finally, we utilize the simulation to compare our PoA bound with actual bound. Second, we study wireless network selection in a distributed environment with Discriminatory Processor Sharing (DPS) scheduling discipline. We consider a set of wireless clients in a network composed of multiple base stations with di erentiated services. The goal of each wireless client is to assign itself to a wireless base station that gives the higher throughput. We formulate the interaction between clients as a weighted congestion game and investigate the existence of equilibria. We show that the equilibrium does not necessarily exists for a general network model. We give several regimes under which the equilibrium is guaranteed to exist. These regimes are implemented either on the base stations or wireless clients. Furthermore, we derive several upper bounds on the equilibrium convergence time and give an extensive simulation to evaluate our results. Third, we consider the interaction between autonomous Wireless Body Area Networks(WBAN) in a crowded environment such as hospital. We propose a dis- tributed approach that mitigates the inter-WBAN interference using the game theory models. The interaction between WBANs is modeled as an in nite repeated game. We propose a "grim" strategy for the formulated game and prove the SPE property under speci c conditions. Furthermore, we investigate the equilibrium by comparing that to a sub-optimal Pareto strategy. We test our results using a speci c simulator designed for WBAN. Finally, we propose a new QoS framework for WBAN architecture. The goal of this framework is to implement a separate QoS layer in the design of WBAN stack protocol so that it becomes independent of the application layer. The framework o ers an application pro le interface where each application can submit its QoS require- ments. The implementation of QoS framework in a separate layer and independent of application layer enables more scalable WBAN application development.
Ph.D. in Computer Engineering, July 2015
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Title: The role of fibrillar collagen in tissue function
Creator: Ma, Yin
Date: 2020
Description: Fibrillar collagen plays an important role in maintaining soft tissue integrity and providing chemical and physical cues for cell fate...
Show moreFibrillar collagen plays an important role in maintaining soft tissue integrity and providing chemical and physical cues for cell fate decisions. Collagen remodeling, which alternates the amount, distribution, and biomechanics of collagen, primarily type I (COLI) and type III (COLIII), can change tissue properties. This process is essential not only in biological developments but also in pathological processes. Thus, it is meaningful to understand the correlation between collagen remodeling and tissue dysfunction and investigate the cells' response to fibrous protein matrices. However, current studies in biochemical analysis of collagen and biomechanical study of tissues were carried out at different scales. So it is hard to correlate the data to draw solid conclusions. In this thesis research, we used two collagen disorder associated pathological conditions, pelvic organ prolapse (POP) and micropapillary serous carcinoma (MPSC) of the fallopian tube, as models to unravel the correlation between tissue dysfunctions and the impaired microenvironment relevant to the composition, nanostructure, and biomechanics of a collagen fibril. In the case of POP, we found the collagen fibers in tissues of POP patients were less abundant but stiffer than those of non-POP individuals, implying a loose and fragile matrix that is weakly integrated with other components of the connective tissue to provide adequate support of the pelvic organs. On the other hand, the collagen D-period, the characteristic banding feature which signals the proper assembly of collagen molecules, decreased in POP tissues. We surmised that the molecular level changes of collagen in POP were accountable for the weak matrix mechanics, verified by a systematic in vitro study. We also examined the collagen matrix alternation in MPSC of the fallopian tube, which is thought to cause ovarian cancer via metastasis. Since cancer metastasis is often related to collagen remodeling, we examined the collagen matrix alternation in this disease. We observed the heterogeneous distribution of COLI and COLIII in the papillae of the tumor tissue. Noticeably, COLI was accumulated at the papillae tip, whereas COLIII was dominant at the papillae base. We also observed the absence of collagen matrix between the micropapillary tip and the fibrosis base. Such an uneven collagen distribution implies that the matrix exerted distinctive forces on the tumor cells to regulate their behaviors, including cell migration, directional growth, and shedding from the primary tumor to initiate metastasis. These conclusions have been supported by the results of our in vitro experiments. In investigating the effect of the microenvironment on cell behavior, we established and validated an AFM-based method to collect and quantitatively analyze the mRNA samples from targeted live cells at the single-cell level. This method overcomes issues, such as severe cell damage or even cell death, the capability of time-dependent and in situ analyses, in current methods. The application of the method in studying heterogeneous gene expression in single cells and the interaction between cancer cells and cancer-associated fibroblasts was demonstrated. We also demonstrated that this method can be potentially used to quantitatively analyze the gene expression level changes in a targeted cell in response to the microenvironment.
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Title: NON-DESTRUCTIVE CANCER DETECTION IN LYMPH NODE USING PAIRED-AGENT MOLECULAR IMAGING
Creator: Li, Chengyue
Date: 2020
Description: Identification of cancer spread to tumor-draining lymph nodes through lymph node dissection and histology offers critical information for...
Show moreIdentification of cancer spread to tumor-draining lymph nodes through lymph node dissection and histology offers critical information for guiding treatment in many cancer types, including breast, melanoma, head and neck, lung and gynecologic cancers, as the lymphatic system serves as the primary route for metastasis. Lymph node biopsy involves localization of tumor-draining lymph nodes, followed by their surgical removal and histological assessment. However, the procedure is associated with overtreatment concerns and some considerable morbidity, including lymphedema, seroma formation, and restricted arm movement. Moreover, conventional histological analyses are time-consuming and laborious, yet pathologists generally examine less than 1% of the volume of each lymph node, leading to undetected micrometastasis (tumor clusters 0.2-2mm in diameter) in 30-60% of cases. In response to these limitations in standard lymph node dissection protocol, there is a significant need for the development of lymph node imaging strategies that are capable of identifying metastatic cancer as a means of staging a patient’s cancer without the need for invasive and time-intensive conventional pathology. Paired-agent imaging molecular imaging protocols have been spearheaded by our group and entail co-administration of a control imaging agent with a molecular targeted agent as a way to account for nonspecific uptake and retention. The overall goal of my thesis was to methodically design, optimize and evaluate the clinical utility of a paired-agent lymph node imaging protocol to achieve levels of sensitivity and specificity in nodal staging not possible with current conventional methods, less invasively and at a fraction of the time and cost.
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Title: AMPLIFICATION AND PURIFICATION OF RECOMBINANT PRO-DEATH BAXΔ2 PROTEINS FOR STRUCTURE ANALYSIS
Creator: Zhou, Yi
Date: 2020
Description: BaxΔ2 is an isoform of the pro-apoptotic Bax family of proteins, which is an important anti-cancer protein. BaxΔ2 behaves differently from...
Show moreBaxΔ2 is an isoform of the pro-apoptotic Bax family of proteins, which is an important anti-cancer protein. BaxΔ2 behaves differently from Baxα to induce apoptosis. The current computationally predicted model of BaxΔ2 is based on known Baxα structure, which is considered biased. Therefore, the elucidation of the BaxΔ2 crystal structure is critical. The goal of this project was to obtain a sufficient amount of purified recombinant Bax∆2 protein for crystallization. We cloned full-length BaxΔ2 fused with a poly-histidine tag on either N-terminus (His-Bax∆2) or C-terminus (Bax∆2-His) into an inducible bacterial expression vector. We found that His-Bax∆2 proteins were expressed better than Bax∆2-His, which totally inhibit host growth. However, the protein concentration of His-Bax∆2 was still too low to be detected by Coomassie blue staining. To increase His-Bax∆2 expression and avoid cytotoxicity, we further tested different bacterial host cells and applied the chaperone system. However, all attempts could not overcome Bax∆2 cytotoxicity and the protein expression levels were not high enough to be feasible for further large-scale purification. The mechanism underlying how Bax∆2 inhibits bacterial growth is still a mystery because Bax∆2 eukaryotic targets (mitochondria and caspases) do not exist in bacteria. Further experiments are required to explore the mechanism of Bax∆2 cytotoxicity in bacteria, so as to finally optimize and elevate the BaxΔ2 protein yields.
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Title: Transactive Energy Market for Electric Vehicle Charging Stations in Constrained Power and Transportation Networks
Creator: Affolabi, Larissa Arielle Sèfiath
Date: 2023
Description: In response to the urgent need for decarbonization, our society is actively working towards reducing carbon emissions across various sectors....
Show moreIn response to the urgent need for decarbonization, our society is actively working towards reducing carbon emissions across various sectors. These efforts have resulted in the widespread adoption of distributed energy resources (DERs) in the electricity sector and the widespread adoption of electric vehicles (EVs) in the transportation sector. The growing popularity of EVs has resulted in rapid growth of charging infrastructure to meet the increasing demand. Recently, combined efforts across those two sectors have gained popularity with the deployment of EV charging stations (EVCSs) with on-site DERs like solar photovoltaic and/or battery energy storage systems not only to defer or avoid the need for power distribution equipment upgrades but also to achieve more environmentally friendly outcomes in terms of decarbonization goals. To increase transportation electrification, we need to expand further the charging infrastructure. The key challenge lies in accelerating charging station deployment while ensuring the safe and efficient operation of the power distribution system where most of this new load will be concentrated. Numerous research efforts have been dedicated to the study of EVCSs, with a focus on either optimizing the pricing of charging services or addressing the energy management challenges from the perspective of system operators. While these aspects are crucial, it is essential to recognize the importance of attracting private sector stakeholders to invest in and support the expansion of the EVCS network. Relying solely on subsidies is insufficient to finance the necessary scale of EVCS deployment required to accelerate the widespread adoption of EVs. The increasing adoption of EVCSs integrated with on-site DERs highlights the potential for Transactive Energy Market (TEM) operations among EVCSs. However, unlike regular prosumers, EVCS operations are uniquely influenced by both the power distribution and the transportation networks. In light of this issue, this dissertation proposes several multi-agent frameworks that leverage on-site DERs at EVCSs to establish a secondary revenue stream through a TEM. This dissertation investigates the technical and economic aspects of these multi-agent frameworks. At its core, we propose two holistic frameworks to solve the energy management problem of EVCSs within a TEM environment. Modeled as independent profit-driven entities, each EVCS optimally schedules its operation based on the day-ahead traffic assignment problem solved by the traffic operator agent. For the TEM clearing process, we propose two distinct lines of approach. First, a centralized approach where a single entity assumes both the market operator and grid operator functions. This integrated approach streamlines the decision-making process and ensures coordinated operations between the market and the power grid. Second, a decentralized approach, where separate entities take on the roles of the market operator and grid operator, respectively. This decentralized structure allows for more flexibility and distributed decision-making within the TEM. Furthermore, in contrast to many TEM related studies that overlook the complexity of the power distribution system, we introduce a comprehensive three-phase unbalanced optimal power flow model. This model incorporates features such as network reconfiguration and tap changers, allowing for a more accurate representation and understanding of the power distribution system's operation. Various case studies are used to prove the effectiveness of our proposed lines of approach to EVCSs’ day-ahead energy management problem.
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Title: Unraveling the Factors Affecting Virus Adhesion to Food Contact Materials and Virus-Virus Interaction – A Nanoscopic Study
Creator: Guo, Ao
Date: 2020
Description: Food safety is a worldwide issue nowadays since pathogens cause diseases, even death. Human enteric viruses are a major cause of non-bacterial...
Show moreFood safety is a worldwide issue nowadays since pathogens cause diseases, even death. Human enteric viruses are a major cause of non-bacterial foodborne gastroenteritis. In the United States, they are the most life-threatening pathogenic agents for the foodborne illnesses. The fecal-oral route is responsible for the attachment and transmission of such foodborne pathogens, which lead to contamination of food-contact materials (FCMs) during food preparation, enhancing the risk of transmission. The interaction between viruses and contact surface is the source of virus adhesion.Due to lack of knowledge on virus adhesion to various FCMs, this thesis aims to reveal the key factors that mediate the virus-FCM and virus-virus interactions in order to effectively prevent virus infection or spread. The objectives are (1) to identify the physical and chemical features of a material surface that affect virus adhesion to determine an optimal FCM, (2) to reduce virus adhesion via nanofabrication of a material’s surface; (3) to investigate the effect of thermal inactivation (heat treatment) on virus-virus interaction toward the establishment of a non-culture-based infectivity assay for laboratory assessment of the effectiveness of disinfection methods. In this study, virus adhesion on various FCMs, including glass, polyvinyl chloride (PVC), polyethylene (PE) and graphite which have been widely used in food storages, food packages and utensil handling during food preparations, was investigated. Male-specific coliphage (MS2) was used as a virus surrogate of the highly infectious human enteric virus with similar physiochemical properties. Atomic force microscopy (AFM) was predominantly used in quantitative analyses of the strength of MS2 adhesion to various food-contact surfaces. Dynamic light scattering (DLS) was applied in MS2 dimensional analysis in aqueous suspension. Moreover, surface modification, such as nanofabrication, was employed to create controllable surface textures to reduce virus adhesion on FCM. Thermal inactivation was employed as a disinfection method. A comparative study was carried out to differentiate the active and inactivated MS2 in the virus-FCM and the virus-virus interactions. The results of this examination indicate that a material’s surface property, such as topography, hydrophobicity and surface charge, contributed to virus adhesion in aqueous phase at neutral pH (=7.4). Each surface feature played a distinctive role; however, the combined effect as well as the chemical signature of a virion’s surface determined the virus-FCM interaction. A delicate control of a surface’s chemical affinity and physical feature is expected to effectively reduce/interfere virus adhesion. It was also discovered that thermally inactivated MS2 particles became larger, softer, and more hydrophobic. These properties can be utilized in developing a non-culture-based assay to assess the effectiveness of disinfection methods for human enteric viruses, which can hardly be cultured in laboratory.
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Title: BIG DATA AS A SERVICE WITH PRIVACY AND SECURITY
Creator: Hou, Jiahui
Date: 2020
Description: With the increase of data production sources like IoT devices (e.g., smartwatches, smartphones) and data from smart home (health sensor,...
Show moreWith the increase of data production sources like IoT devices (e.g., smartwatches, smartphones) and data from smart home (health sensor, energy sensors), truly mind-boggling amounts of data are generated daily. Building a big data as a service system, that combines big data technologies and cloud computing, will enhance the huge value of big data and tremendously boost the economic growth in various areas. Big data as a service has evolved into a booming market, but with the emergence of larger privacy and security challenges. Privacy and security concerns limit the development of big data as a service and increasingly become one of the main reasons why most data are not shared and well utilized. This dissertation aims to build a new incrementally deployable middleware for the current and future big data as a service eco-system in order to guarantee privacy and security. This middleware will retain privacy and security in the data querying and ensure privacy preservation in data analysis. In addition, emerging cloud computing contributes to providing valuable services associated with machine learning (ML) techniques. We consider privacy issues in both traditional queries and ML queries (i.e., ML classification) in this dissertation. The final goal is to design and develop a demonstrable system that can be deployed in the big data as a service system in order to guarantee the privacy of data/ service owners as well as users, enabling secure data analysis and services.Firstly, we consider a private dataset composed of a set of individuals, and the data is outsourced to a remote cloud server. We revisit the classic query auditing problem in the outsourcing scenario. Secondly, we study privacy preserving neural network classification where source data is randomly partitioned. Thirdly, we concern the privacy of confidential training dataset and models which are typically trained in a centralized cloud server but publicly accessible, \ie online ML-as-a-Service (MLaaS). Lastly, we consider the offline MLaaS systems. We design, implement, and evaluate a secure ML framework to enable MLaaS on clients' edge devices, where a ``encrypted'' ML models are stored locally.
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Title: LOW-DOSE CARDIAC SPECT USING POST-FILTERING, DEEP LEARNING, AND MOTION CORRECTION
Creator: Song, Chao
Date: 2019
Description: Single photon emission computed tomography (SPECT) is an important technique in use today for the detection and evaluation of coronary artery...
Show moreSingle photon emission computed tomography (SPECT) is an important technique in use today for the detection and evaluation of coronary artery diseases. The image quality in cardiac SPECT can be adversely affected by cardiac motion and respiratory motion, both of which can lead to motion blur and non-uniform heart wall. In this thesis, we mainly investigate imaging de-noising algorithms and motion correction methods for improving the image quality in cardiac SPECT on both standard dose and reduced dose.First, we investigate a spatiotemporal post-processing approach based on a non-local means (NLM) filter for suppressing the noise in cardiac-gated SPECT images. Since in recent years low-dose studies have gained increased attention in cardiac SPECT owing to its potential radiation risk, to further improve the image quality on reduced dose, we investigate a novel de-noising method for low-dose cardiac-gated SPECT by using a three dimensional residual convolutional neural network (CNN). Furthermore, to reduce the negative effect of respiratory-binned acquisitions and assess the benefit of this approach in both standard dose and reduced dose using simulated acquisitions. Inspired by the success in respiratory correction, we investigate the potential benefit of cardiac motion correction for improving the detectability of perfusion defects. Finally, to combine the benefit of above two types of motion correction, dual-gated data acquisitions are implemented, wherein the acquired list-mode data are further binned into a number of intervals within cardiac and respiratory cycle according to the electrocardiography (ECG) signal and amplitude of the respiratory motion.
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Title: Analysis of High-Fidelity Experiments and Simulations of the Flow in Simplified Urban Environments
Creator: Stuck, Maxime
Date: 2020
Description: The mean ﬂow and turbulence statistics of the ﬂow through a simpliﬁed urban environment, which is an active research area in order to improve...
Show moreThe mean ﬂow and turbulence statistics of the ﬂow through a simpliﬁed urban environment, which is an active research area in order to improve the knowledge of turbulent ﬂow in cities, is investigated. This is useful for civil engineering, pedestrian comfort and for health concerns caused by pollutant spreading. In this work, we provide analysis of the turbulence statistics obtained both from highly-quality stereoscopic particle image-velocimetry (SPIV) measurements (from Monnier et al.) and well-resolved large eddy simulations (LES) by Torres et al. A detailed comparison of both databases reveals the impact of the geometry of the urban array on the ﬂow characteristics and provides for a good description of the turbulent features of the ﬂow around a simpliﬁed urban environment. The most prominent features of this complex ﬂow include coherent vortical structures such as the so-called arch vortex, the horseshoe vortex, or the roof vortex. These structures of the ﬂow have been identiﬁed by an analysis of the turbulence statistics. The inﬂuence of the geometry of the urban environment (and particularly the street width and the building height) on the overall ﬂow behavior has also been studied.
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