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Title: COMPARISON OF THE EFFICACY OF THREE SANITIZERS WITH 20,000 PPM CALCIUM HYPOCHLORITE FOR INACTIVATION OF SALMONELLA ON ARTIFICIALLY CONTAMINATED ALFALFA SEEDS
Creator: Li, Qing
Date: 2015, 2015-12
Description: This study evaluated the efficacy of three alternative sanitizers, acidified sodium chlorite (ASC, also known as Sanova), stabilized oxychloro...
Show moreThis study evaluated the efficacy of three alternative sanitizers, acidified sodium chlorite (ASC, also known as Sanova), stabilized oxychloro-based sanitizer (SOC, also known as Germin-8-or), and Tsunami 100 in comparison with 20,000 ppm Ca(OCl)2 for treatment of alfalfa seeds artificially inoculated with Salmonella. Small-scale experiments were conducted to determine the best treatment conditions for each sanitizer and how the initial Salmonella contamination level on seeds or Salmonella type may have on the efficacy of the sanitizers. Large-scale studies were performed to evaluate the commercial applicability of these sanitizers. As a comparison, seeds were also treated with 20,000 ppm Ca(OCl)2 for 15 min. To determine the optimal treatment condition, ten g of seeds containing 103 CFU/g (seed lot 1) or 105 CFU/g (seed lot 2) of S. Typhimurium expressing green fluorescent protein was treated with different concentrations of ASC, SOC, and Tsunami 100 for different period of treatment time. Results showed that the efficacy of ASC and SOC increased with increasing concentrations (up to 1500 ppm) and treatment time (up to 3 h); however, the germination rates for seeds treated with > 1200 ppm of either sanitizer was < 80%. When seeds from lot 1 were treated with 800 ppm of ASC or SOC for 3 h, the level of Salmonella reduced, respectively, by 2.6 log units or >2.5 log units to an undetectable level, compared with the 1.1 log unit decrease observed in seeds treated with Ca(OCl)2. When seeds from seed lot 2 (5 log units) were treated with 800 ppm of ASC or SOC for 3 h, the level of Salmonella were reduced by 3.8 log units or >4.3 log units to an undetectable level, respectively, compared with the 2 log units decrease observed in seeds treated with Ca(OCl)2. Treatment with 80 ppm of Tsunami 100 from 10 min to 24 h kept the germination rate higher than 85% but only reduced the Salmonella count by 0 to 1.8 log units. Between two seed lots, results of ASC showed that sanitizer could reduce more pathogen when the seeds contained higher initial Salmonella level. Ten g of seeds containing 105 CFU/g of four-strain cocktail of Salmonella was treated with ASC and SOC by optimal treatment condition. SOC and ASC eliminated Salmonella number by 2.8 and 1.6 log units respectively, less effective compare with the treatment of seed lot 1. For large-scale runs, 1 kg of seeds spiked with 1 % (w/w) of inoculated seeds containing 105 CFU/g of S. Typhimurium was treated with SOC and ASC under optimal treatment conditions. Salmonella level in seeds treated with 800 ppm SOC or ASC for 3 h decreased by 3.9 or 3.6 log units, compared with a 3.3 log reduction in seeds treated with 20,000 ppm Ca(OCl)2. The stabilized oxychloro-based sanitizer may provide an alternative seed treatment method for sprout growers.
M.S. in Food Safety and Technology, December 2015
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Title: THE CHARACTERIZATION OF TWO THERMOPHILIC STRAINS CONCERNING BIO-DESULFURIZATION OF DIBENZOTHIOPHENE BY THE 4S PATHWAY
Creator: Li, Enze
Date: 2016, 2016-05
Description: A moderately thermophilic Mycobacterium strain (denoted Myco-U) was isolated in our lab as a contaminant during the cultivation of another...
Show moreA moderately thermophilic Mycobacterium strain (denoted Myco-U) was isolated in our lab as a contaminant during the cultivation of another thermophilic Paenibacillus strain, and has been proved to harbor the genes that encode the enzymes for dibenzothiophene (DBT) biodegradation via the 4S pathway; this makes it possible to efficiently remove organosulfur compounds (e.g. DBT and DBTO2) from the crude petroleum. Through directed evolution (continuous passage and selection with increasing temperature), the Myco-U strain has shown moderate capacity of metabolizing DBT to 2-hydroxybiphenyl (2-HBP) by the 4S pathway at a thermophilic temperature (~53 ℃). In the middle-to-late stages of the selections, a stubborn contaminant (denoted Bacillus X) arose and has remained difficult to get rid of from our medium and cultures ever since, leading to a persistent contamination and repetition of our experiments. The reason why Bacillus X is regarded as a contaminant is that it does not obtain sulfur by the expected means (e.g., DBT desulfurization), but utilizes the tiny amount of sulfate from the vitamin mix and 50 μg/ml yeast extract in our medium to grow. This is confirmed by the facts that Bacillus X does not yield any detectable 2-HBP, and a significant difference of growth has been detected between cultures with DBT as the sole sulfur source and the positive controls, which employs Na2SO4 as sulfur source. Through 16S rDNA amplification, cloning, and sequencing, Bacillus X was identified as a Bacillus species, and shows the highest homology (99 % identical) to a specific uncultured bacterium clone (NCBI #Accession: JN882111.1). The chromogenic mechanism and impacts of pH and carbonate upon the Gibbs assay, by which 2-HBP is quantified, were investigated. When DBT is absent or at undetectably low levels, cultures measured by the assay display a yellowish-to-brownish background after adding the Gibbs reagent (2,6-dichloroquinone-4-chloroimide). According to our results, the Gibbs reaction prefers alkaline conditions and pH 8.0 ranks the optimal (compared with pH 7.0, 7.5, 8.5 and 9.0) at which the maximum A610nm is detected.
M.S. in Biology, May 2016
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Title: CYBER ATTACKS AGAINST STATE ESTIMATION IN POWER SYSTEMS: VUNERABILITY ANALYSIS AND PROTECTION STRATEGIES
Creator: Liu, Xuan
Date: 2015, 2015-07
Description: Power grid is one of the most critical infrastructures in a nation and could suffer a variety of cyber attacks. With the development of Smart...
Show morePower grid is one of the most critical infrastructures in a nation and could suffer a variety of cyber attacks. With the development of Smart Grid, cyber security has become an area of growing concern. False data injection attack has recently attracted wide research interest. This thesis proposes a false data attack model with incomplete network information and develops optimal attack strategies for attacking load measurements and the real-time topology of a power grid. The impacts of false data on the economic and reliable operations of power systems are quantitatively analyzed in this thesis. To mitigate the risk of cyber attacks, a distributed protection strategies are also developed. It has been shown that an attacker can design false data to avoid being detected by the control center if the network information of a power grid is known to the attacker. In practice, however, it is very hard or even impossible for an attacker to obtain all network information of a power grid. In this thesis, we propose a local load redistribution attacking model based on incomplete network information and show that an attacker only needs to obtain the network information of the local attacking region to inject false data into smart meters in the local region without being detected by the state estimator. A heuristic algorithm is developed to determine a feasible attacking region by obtaining reduced network information. This thesis investigates the impacts of false data on the operations of power systems. It has been shown that false data can be designed by an attacker to: 1) mask the real-time topology of a power grid; 2) overload a transmission line; 3) disturb the line outage detection based on PMU data. To mitigate the risk of cyber attacks, this thesis proposes a new protection strategy, which intends to mitigate the most damaging effect of LR attacks on power system operation. The objective is to mitigate the damage effects of false data injection attacks by increasing the attacking cost of an attacker. This is achieved by protecting a small set of critical measurements. To further reduce the computation complexity, we also propose a mixed integer linear programming approach to separate the power grid into several subnetworks, then distributed protection strategy is applied to each subnetwork. The results of this thesis reveal the mechanism of local false data injection attacks and highlight the importance and complexity of defending power systems against false data injection attacks.
Ph.D. in Electrical and Computer Engineering, July 2015
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Title: CHANGES OF BACTERIAL SPECIES AND HEME PROTEIN LEVEL IN ACTIVATED SLUDGE COMMUNITIES ACCLIMATED TO LOW AERATION
Creator: Li, Hainan
Date: 2016, 2016-05
Description: Increasing oxygen utilization of activated sludge under low dissolved oxygen (DO) conditions can lead to energy savings in wastewater...
Show moreIncreasing oxygen utilization of activated sludge under low dissolved oxygen (DO) conditions can lead to energy savings in wastewater treatment systems. Adaptation of sludge communities to low oxygen conditions may be facilitated by increased expression of heme proteins. One way to assess heme protein expression in sludge is to analyze the species present in the sludge community during the adaptation process. In the work reported here, growth of a sludge culture adapted by Kunkel to low aeration for 48 weekly passages was continued for an additional 26 passages (182 days). The activated sludge was cultured in synthetic wastewater under low DO conditions. Temperature, dissolved oxygen, and specific oxygen uptake rates (SOUR) were measured at the end of each weekly passage. The community structures of passages 50, 53 and 65 were determined by 16S rDNA cloning techniques. The type of heme present was identified using the pyridine hemochromogen method. The SOUR values measured increased slightly in the first part of the experiment, when the culture DO was very low, but then decreased in the latter part of the experiment, when the culture DO increased. The community structure diversity in passage 50 in Kunkel’s study and passage 50 from this work are totally different in terms of species present, even though the two cultures were both derived from Kunkel’s passage 48 and were grown under conditions which were matched as closely as possible for two additional passages. This indicates that the community structure is highly sensitive to small changes in growth conditions. From the point of view of types of hemoglobin (Hb), the community became more diverse by passage 53, containing all three types of truncated Hb (trHbN, trHbO, and trHbP), possibly due to the need for NO scavenging and oxygen transfer enhancement. The proportion of cells that synthesize truncated Hb decreased slightly through passages 50 to 53 to 65. The percentage of cells that encode FlavoHbs decreased from 84 % to 50 % by passage 65. Overall there was an increase in Hb expression from passage 50 to passage 65. Heme b expression in the sludge culture was confirmed. Successful adaptation of the sludge culture to low DO conditions via enhancement of oxygen uptake was not obvious in this study. Yet the overall tendencies of SOUR and Hb expression suggest that it is possible to acquire a culture more efficient in oxygen uptake if a stable low aerobic environment can be maintained for an extended period.
M.S. in Biology, May 2016
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Title: INVESTIGATION OF OXYGEN GENERATION DURING THE OPERATION OF LITHIUM-ION CELLS USING IN-SITU FLUORESCENCE SPECTROSCOPY
Creator: Li, Mo
Date: 2016, 2016-07
Description: An ex-situ fluorescence spectroscopy system was set up and utilized to study the interaction of fluorescent dyes with an oxygen quencher. The...
Show moreAn ex-situ fluorescence spectroscopy system was set up and utilized to study the interaction of fluorescent dyes with an oxygen quencher. The Stern-Volmer relationship was obtained and fitted to correlate the partial pressure of oxygen to the dye fluorescence intensity. The oxygen quenching constant α for 30 μM 9,10-dimethylanthracene_(DMA) dissolved in the mixture of ethylene carbonate_(EC) and dimethyl carbonate_(DMC) (1:1 volume ratio) were 0.69/0.62 at high/low partial pressure of oxygen. Operation of the self-made pouch cells with LiCoO2 as the cathode material was examined by charging/discharging at C/10. The discharge capacities were 107 and 104 mAh/g for the pouch cell both with and without the optical probe, which indicates that the optical probe did not significantly affect the performance and capacity of the cell. The optical probe was inserted into the pouch cell to measure the fluorescence intensity of the dye that was dissolved in the electrolyte. Time series experiments before charging demonstrated that the fluorescence intensity was stable for at least 24 hours. However, the fluorescence intensity decreased abruptly as the voltage of the pouch cell increased during the initial stages of charging, which means that the dye (DMA) could not be employed to detect the oxygen generated in the cell. Both the real-time fluorescence spectroscopy and the cyclic voltammetry illustrated that this dye was not suitable for the in-situ fluorescence tests. The electrochemical stability at room temperature of different dyes such as anthracene, Palladium (II) meso-tetrakis (pentafluorophenyl porphyrin)_(PTTFPP) and Platinum octaethylporphyrin_(PtOEP) were examined in the organic solvents used in the electrolytes in Li-ion cells. Cyclic voltammograms of anthracene and PTTFPP showed oxidation peaks at 2V and reduction peaks at around 1V, with the possible formation of the radical anion causing spectral changes. The chemical compound 1-hexyl-3- methylimidazolium bis (trifluormethylsulfonyl)imide_(HMIM BTI) was electrochemically stable, but the fluorescence intensity was too low (5% of dye DMA) to be used in the in-situ detection of oxygen. As a result, more work must be performed in the future to find a suitable dye. Keywords: fluorescence spectroscopy, in-situ Li-ion cell operation, quencheroxygen, the Stern-Volmer relationship
M.S. in Chemical Engineeering, July 2016
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Title: DEVELOPMENT OF A MOBILE AD-HOC NETWORK USING WI-FI DIRECT OVER ANDROID PLATFORM
Creator: Liu, Kecheng
Date: 2015, 2015-12
Description: The proliferation of smart phones enables ubiquitous Mobile Ad-hoc Networks (MANETs) where mobile devices communicate with peers over a...
Show moreThe proliferation of smart phones enables ubiquitous Mobile Ad-hoc Networks (MANETs) where mobile devices communicate with peers over a wireless channel in an ad hoc mode. In this paper, we introduce a novel method to achieve multi-hop communication among open-source, non-rooted Android devices using Wi-Fi Direct Technology (also known as Wi-Fi Peer-to-Peer (P2P» . We then implement an MANET with proactive routing using device s MAC addresses by conducting experim ents using off-the-shelf smartphones.
M.S. in Electrical Engineering, December 2015
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Title: LOW TEMPERATURE STORAGE METHODS FOR SKINNED MANDUCA SEXTA FLIGHT MUSCLE
Creator: Liu, Xue
Date: 2015, 2015-12
Description: The flight muscle of the Hawk moth, Manduca sexta, is a synchronous muscle and an emerging model system for structure and function studies of...
Show moreThe flight muscle of the Hawk moth, Manduca sexta, is a synchronous muscle and an emerging model system for structure and function studies of muscle. (Tu & Daniel, 2004). There are several interesting properties of Manduca sexta flight muscle. In its physiological characteristics, like mammalian skeletal and cardiac striated muscle, it is a synchronous muscle. However, it is much more similar structurally to the more widely known asynchronous insect flight muscles of Drosophila and Lethocerus. Up to now there has been no good method for storing Manduca sexta flight muscle for a long time. It is often difficult to match the time of obtaining live moths muscle and scheduled X-ray or mechanics experiment. Usually, best results are obtained by using freshly prepared muscle fibers. It would be highly desirable to find storage conditions that can maintain the structural and physiological functions in vitro for days or weeks rather than needing to be prepared fresh from living tissue for every experiment. (Yu-Shu Cheng, MS thesis IIT, 2013). Muscle proteins will degrade over a periods of days even in the presence of protease inhibitors even at low temperature. Here we aimed to find storage conditions which would work best for Manduca sexta flight muscle. In this thesis, trehalose, in combination with glycerol, was evaluated as an addition storage solution as a cryoprotectant to protect the muscle fiber from the low temperature. At very low temperature, organisms became dehydrated. Loss of liquid water from cells can cause irreversible damage, so they will not function even when rehydrated. Here we show that using both glycerol and trehalose as cryoprotectants in storage solution, the muscle fiber maintain high maximum active force for up to a month in storage.
M.S. in Biology, December 2015
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Title: COMPUTATIONAL COST OF SIMULATING MEAN EXIT TIME USING STOCHASTIC DIFFERENTIAL EQUATIONS
Creator: Liu, Fanjing
Date: 2016, 2016-05
Description: Stochastic di erential equations play an important role in modern science, including engineering, physics, computer science and nance. It has...
Show moreStochastic di erential equations play an important role in modern science, including engineering, physics, computer science and nance. It has been shown that numerically solving stochastic di erential equation is a productive methodto deal with such problems. In this work, we try to analyze the procedure of numerically computing the mean exit time of some stochastic processes from a given boundary using Monte Carlo simulations. The two methods, including the Euler-Maruyama Method and Milstein's higher order method, will be explained and used extensively when we simulate paths of the random process. The simulated processes generated through the methods will then be used to identify the exit times. Later we use the average of the exit times as a numerical solution of Mean Exit Time. We compare the e ciency of the above two methods by evaluating their computational complexity and CPU cost of reaching the same level of accuracy.
M.S. in Applied Mathematics, May 2016
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Title: TEMPORAL AND SPATIOTEMPORAL MODELS FOR SHORT-CRIME PREDICTION
Creator: Liu, Xiaomu
Date: 2017, 2017-07
Description: One of the most important aspects of predictive policing is identifying the likely time and place of crime occurrences so as to prevent future...
Show moreOne of the most important aspects of predictive policing is identifying the likely time and place of crime occurrences so as to prevent future crimes. The ability to make short-term predictions may be of particular importance for optimizing police resource allocation. The goal of this study is to investigate the temporal and spatiotemporal pattern of crime in the city of Chicago and to build corresponding predictive models. First, a temporal model for forecasting citywide violent crime time count is proposed. This model is composed of a long-term trend and short-term variations using data of time, weather and crime. The importance of model reproducibility is addressed in this study to produce low-complexity models. We introduce an approach that provides a way to extend the model selection criterion to both prediction accuracy and model reproducibility. The experimental results show that models produced by this approach outperform several simple time-series models. It is also found that these models typically include fewer variables; therefore, they are more interpretable, and may provide superior generalization error. Next we develop a framework that provides predictions for tomorrow’s violent crime counts at the level of a police district. The procedures include citywide daily violent crime count prediction, violent crime density estimation, and distributing citywide predictions to districts according to the estimated densities. In order to estimate the crime spatial densities, we use mesh modeling and demonstrate that a mesh model can be used as the structure for modeling the spatial variation of crime rate since it is well adapted to the inhomogeneous crime distribution. The experimental results show that our method provides more-accurate forecasts than those given by historical crime statistics. One aspect of studying spatial pattern of crimes is identifying geographical regions with similar crime characteristics. Specifically, we illustrate applying unsupervised clustering techniques to segment the city into sub-regions. We explore the use of Gaussian mixture models combined with a Markov random field for the purpose of regularization. We also propose a framework for the evaluation of clustering models without knowing the ground truth, which can present a more-complete picture for model selection in unsupervised clustering problems. Finally, we develop a spatiotemporal prediction method that predicts the locations where violent crimes or property crimes are most likely to occur tomorrow. Crime incidents are rasterized by a spatiotemporal grid. Other factors that affect the time and location preferences of criminal activities are also leveraged and represented by that grid. Each spatiotemporal grid cell is treated as an example for training and testing our models. We also explore whether pooling data from various sub-regions based on spatial clustering can improve model performance. The experimental results show that our models are more accurate than conventional hot-spot models. It is found that the effects of using different training samples are not consistent, which depends on target crime type.
Ph.D. in Electrical Engineering, July 2017
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Title: License Plate Recognition in Complex Scenes
Creator: Wazalwar, Dhawal S.
Date: 2011-12-07, 2011-12
Description: License plate recognition is considered to be one of the fastest growing tech- nologies in the field of surveillance and control. In this...
Show moreLicense plate recognition is considered to be one of the fastest growing tech- nologies in the field of surveillance and control. In this project, we present a new design flow for robust license plate localization and recognition. The algorithm con- sists of three stages: i) license plate localization ii) character segmentation and iii) feature extraction and character recognition. The algorithm uses Mexican hat opera- tor for edge detection and Euler number of a binary image for identifying the license plate region. A pre-processing step using median filter and contrast enhancement is employed to improve the character segmentation performance in case of low resolution and blur images. A unique feature vector comprised of region properties, projection data and reflection symmetry coefficient has been proposed. Back propagation artifi- cial neural network classifier has been used to train and test the neural network based on the extracted feature. A thorough testing of algorithm is performed on a database with varying test cases in terms of illumination and different plate conditions. The results are encouraging with success rate of 98.10% for license plate localization and 97.05% for character recognition.
M.S. in Electrical Engineering, December 2011
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Title: Lightning arresters and schemes for testing
Creator: Morey, C. R., Oehne, T. C. Jr
Date: 2009, 1908
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/lightningarreste00more
Thesis (B.S.)--Armour Institute of Technology

Title: A CONCEPTUAL ENERGY DESIGN FOR O’HARE INTERNATIONAL AIRPORT USING WIND AND BUILDING INTEGRATED PHOTOVOLTAIC SYSTEMS
Creator: Gomez Soriano, Maria
Date: 2014, 2014-12
Description: Commercial buildings account for approximately 18% of the total energy use in the United States, although only 7% of this consumption is...
Show moreCommercial buildings account for approximately 18% of the total energy use in the United States, although only 7% of this consumption is currently supplied by renewable energy sources, including hydropower, biomass, geothermal, wind, and solar heat and photovoltaics. This is a low percentage and it is imperative to explore potentials for using a combination of renewable energy systems to increase this percentage, particularly for large establishments with large land areas and existing facilities that can support large amounts of renewable energy technologies, such as airports. O’Hare International Airport (ORD), located in Chicago (Illinois), has been selected for this research, with the main purpose of supplying the maximum possible amount of the airport energy demand by a proposed wind and solar hybrid system. The first part of this research includes a wind energy system design performed using wind speed data at ORD locations and determining a suitable number and type of turbines loacted within the airport premises. Special considerations are made for for height, turbine locations, and prevailing wind directions. The second part of the study involves design of solar photovoltaic panel arrays both for existing terminals as well as for a proposed new terminal. The design of the arrays includes considerations for optimal energy production with varying installation angles as well as the number of sunny days useful for sun energy harvesting. Finally, the total electricity output from the hybrid system is estimated and compared with the total and monthly electricity demand at ORD. Results show that a considerable percentage of the electricity demand at ORD can be obtained through the wind and solar hybrid system. Specifically, if the airport authority decides on a new terminal, the integration of PV panels with the new terminal structure can be optimized such that the pecentage of total electricty demand at ORD could be met by more than 50% on-site renewable energy sources. An analysis of potential return in investment reveals that economically such a design is viable and can result in sizeable annual savings over a 20-year investment period.
M.S. in Civil, Architectural and Environmental Engineering, December 2014
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Title: MOTIVATING CONSTRUCTION PROJECT MANAGERS AND ASSESSING THEIR HUMAN VALUES: THE VALUE/MOTIVATION LINKAGE
Creator: Wang, Di
Date: 2011-11-29, 2011-12
Description: Worker productivity and performance are critical to companies. Workers’ motivation has typically been investigated based on the well-known...
Show moreWorker productivity and performance are critical to companies. Workers’ motivation has typically been investigated based on the well-known hierarchical need theory of Maslow (1943), the two-factor need theory of Herzberg (1968), the need theory of Alderfer (1972), and the expectancy theory of Vroom (1964). Construction managers occupy middle management positions and are as important as regular workers to the success of a project. Therefore, construction managers’ motivation should also be investigated. This study investigates the factors that motivate construction managers, and the human value of construction managers. The motivators are extracted from previous studies and the human values from Rokeach’s (1973) work. The relationship between construction managers’ human values and the motivators is explored, which previous studies never attempted before is implemented in this study. 101 out of 1000 construction managers participated in a survey asking them to rate the importance of 20 motivators and 18 human values. Factor analysis was used to reduce the 20 motivators to six factors. Inter-correlation analysis was conducted and the 18 human values were reduced to 9. Multiple regression analysis was conducted between the 9 human values against each one of the motivation factors. However, the R2 were low. Therefore artificial neural networks (ANN) were used to analyze the relationship. The ANN model was able to predict the relationship between human values and each of the six motivational factors with 75% accuracy. If higher executives are able to determine the human values of their construction managers, they should be able to motivate their construction managers by promoting the appropriate motivators.
M.S. in Civil Engineering, December 2011
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Title: A STUDY OF HIGH FREQUENCY TRADING IN LIMIT ORDER BOOKS
Creator: Jiang, Yuan
Date: 2013, 2013-12
Description: In the thesis we study the high frequency trading and its applications in limit order books. We discuss the basic concepts and review the...
Show moreIn the thesis we study the high frequency trading and its applications in limit order books. We discuss the basic concepts and review the models in the limit order books. The review section focuses on the queues in the limit order books, optimal trading strategies, short-term volatilities and multi-agent problems in the scenario of limit order markets. Discussions on the shortage of some prevalent models of limit order books are addressed thereafter. For the main results of the thesis, market data are calibrated to facilitate the comparison between a theoretical model and the empirical behaviors in terms of order flows, price changes and diffusion limit of prices.
M.S. in Applied Mathematics, December 2013
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Title: INDUCTION MOTOR MODELING FOR ELECTROMECHANICAL DYNAMIC SIMULATION AND ELECTROMAGNETIC TRANSIENT SIMULATION
Creator: Aserkar, Chandrahas
Date: 2011-11-21, 2011-12
Description: The initial part of this research work focuses on distribution power flow for agent based distribution systems. Power flow analysis is an...
Show moreThe initial part of this research work focuses on distribution power flow for agent based distribution systems. Power flow analysis is an essential tool for power system planning and operation. Traditionally, most distribution systems are radial or weakly meshed types. Faced with the power markets of today, increasing requirements for reliability and ongoing distributed generation have meant that the structure of the distribution systems has become more complex. Also, with the advent of smart- grid technology, distribution automation and micro-grids, the distribution systems are focusing towards distributed control with the use of smart switches via agents. Thus the need for power flow analysis in such systems becomes more important than before. The forward-backward sweep method is a very popular method for distribution power-flow analysis. But, the traditional forward-backward sweep method focuses on the load flow solution based on the bus-injection to branch-current (BIBC) matrix, which is calculated considering the network topology. For distribution systems focus- ing on distributed control, the complete distribution network topology is unknown to any one agent and hence the complete BIBC matrix is not formed. Rather, the property of these agents to communicate with each other is exploited to obtain the power flow solution. Here, we focus on altering the network topology based algo- rithm for forward-backward sweep method so as to make it suitable for agent based distribution systems. The later part of this research work focuses on development of induction motor load models for transient dynamic stability simulators (TS) and electromagnetic tran- sient simulators (EMT), to study the voltage stability of power systems. A Transient Stability simulator runs at a larger time step and is used to study relatively slower dynamics in the system. On the other hand, an Electromagnetic Transient simulator uses a smaller time step to capture the fast dynamics in the system. A combined TS-EMT simulator attempts to model the bulk of the system as a slowly varying dynamic system and a small portion of the system for which the fast dynamics are to be studied, with an electromagnetic transient model. Load modeling is a very important aspect for studying power system stability. Power system stability is the property of a power system that insures the system remains in electromechanical equilibrium throughout any normal and abnormal oper- ating conditions. It is thus defined as the ability of designated synchronous machines in the system to remain in synchronism with one another following disturbance at various locations in the system. It also indicates the ability of induction motors in the system to maintain electrical torque to carry the load following these disturbances. This research work provides a detailed modeling of the induction motor for electrome- chanical as well as electromagnetic transient simulations and uses them to study the effects of composite load models on power system voltage stability.
M.S. in Electrical Engineering, December 2011
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Title: AN EMPIRICAL APPROACH TO GASSIFICATION PROCESS MODELING AND ASSESSMENT
Creator: Rahmaninejad, Fatemeh
Date: 2013-05-01, 2013-05
Description: There has been growing interest in estimating the flow rate and composition of fuel gases produced from gasification of coal and other...
Show moreThere has been growing interest in estimating the flow rate and composition of fuel gases produced from gasification of coal and other carbonaceous solid fuels. In general, coal gasification processes are complex, and because of the high costs associated with the experimental investigations, modeling and simulation tools are needed to assist with the design, analysis, and optimization of these complex processes. Most of the efforts in the development of gasifier models have focused on two different approaches; equilibrium modeling and kinetic modeling. The chemical equilibrium approach assumes the gasification reactions have sufficiently fast kinetics and reach global chemical reaction equilibria, which leads to over-prediction of the extent of the gasification reactions [1, 2, 3]. On the other hand, the kinetic based models require detailed knowledge of hydrodynamic and reaction kinetics of the heterogeneous and homogeneous chemical reactions [4, 5]. Because of the dependence of the product gas (composition and flow rate) on a broad ranges of certain key operating variables such as gasifier design, configuration, and coal type the gasification model needs to take into account the effect of those parameters based on available experimental data. In this study, a versatile and user-friendly gasifier simulation model was developed which incorporates a MS Excel interface aiming to provide a guide to gasification process analysis, evaluation and improvement. The model uses a set of empirical “default” correlations, for the reaction conversions that were obtained from xi regression analysis of the available experimental data to predict the syngas composition, flow rate, and performance of the gasifier based on the operating conditions specified by the user. The results of the parametric studies performed for assessment of the effect of operating conditions are discussed and presented.
M.S. in Chemical Engineering, May 2013
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Title: SELF-ESTEEM AS A MEDIATOR OF ASSOCIATIONS BETWEEN AFFECT AND BODY IMAGE IN A SAMPLE OF MALE AND FEMALE UNDERGRADUATES
Creator: Hansen, Meghan
Date: 2013, 2013-12
Description: Body image is a multidimensional construct that encompasses how individuals perceive their body. One frequently studied component of body...
Show moreBody image is a multidimensional construct that encompasses how individuals perceive their body. One frequently studied component of body image is body dissatisfaction. Body dissatisfaction has been associated with numerous negative outcomes including increased negative affect, increased maladaptive dieting behaviors and increased eating pathology. Psychological factors, including depression, anxiety, well-being, and self-esteem have been implicated in body dissatisfaction ; however, little is known about associations between these psychological factors and the larger construct of body image. This study examined associations among depression, social anxiety, well-being, self-esteem and body image in a diverse sample of undergraduate men and women. Correlation and regression analyses were conducted to 1) examine bivariate associations between affect and body image and 2) self-esteem as a moderator or mediator of these associations. Results demonstrated significant correlations between affect, body image, and self-esteem. Additionally, self-esteem mediated the relationship between affect and various components of body image, and these results varied based on gender. Findings have important implications for treatment and prevention efforts.
M.S. in Psychology, December 2013
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Title: MOBILITY IMPROVEMENT BENEFIT ANALYSIS OF SIGNAL TIMING OPTIMIZATION FOR URBAN STREET NETWORK
Creator: Zhang, Ji
Date: 2015, 2015-05
Description: The traffic congestion problem especially in urban areas is getting increasingly severe due to the ever-growing auto travel demand in the...
Show moreThe traffic congestion problem especially in urban areas is getting increasingly severe due to the ever-growing auto travel demand in the United States during the past few decades. In general, insufficient capacity can be solved by system expansion. However, expanding system is not feasible anymore because of the land scarcity in urban areas and its high cost. From this point of view, transportation operations that lead to the optimal system usage are more preferable thanks to their relatively low cost and remarkable consequences. Several performance indices were used in order to assess the effects of a given transportation operation. This study introduces a new method for evaluating the mobility performance of the transportation system before and after a transportation operation. And the mobility benefit is converted into monetary value. Further, a Life-Cycle Benefit Analysis is conducted to expand the evaluation process to the time dimension. An experimental study is performed to apply this method on the urban street network in Chicago downtown area that contains 917 intersections and 1675 roadway segments before and after a network-wide signal timing optimization treatment. Based on this application, the results indicate a few potential advantages and disadvantages of this system-wide signal timing optimization methodology.
M.S. in Civil Engineering, May 2015
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Title: FEM-BASED MULTIPHYSICS MODELING OF CONTAMINATION AND REMEDIATION OF VARIABLY SATURATED SOILS
Creator: Miao, Tao
Date: 2015, 2015-05
Description: With the increasing awareness of environmental protection, the soil contamination has been a major problem in this industrial world. This...
Show moreWith the increasing awareness of environmental protection, the soil contamination has been a major problem in this industrial world. This study aims to develop numerical tools to simulate the soil pollution process and evaluate the effectiveness and efficiency of remediation solutions. First of all, a mathematical model was built to describe the pollutants (chemical species) transport phenomenon in soil, especially under unsaturated states. The model is developed based on mass conversation principle and two mechanisms were taken into account, including natural diffusion and convective flow. In order to obtain the flow velocity in soil, a variety of material parameters for soil such as permeability and hydraulic conductivity should be determined. The Richard’s equation, commonly used in formulating soil-water characteristic curves, was adopted to study moisture movement in the variably saturated soils. The model was applied to predict multiple pollutant species transporting in clayey, silty and sandy soils. Second, as a new coming method, electrokinetic remediation has been proven an effective and sustainable solution to clean up contaminated soil. Resulting from the added external electrical field, electroosmosis and electromigration were generated, which can remove pollutant ions from the polluted soil domain. A second model was built to evaluate cleaning up efficiency of electrokinetic solution, and then implemented to simulate remediation of soil contaminated by nuclear waste. The last part of this study aims to focus on another remediation solution. Bioremediation is becoming an effective method for treating soils or geo-materials contaminated by organic pollutants. Bioremediation can be defined as introduction of bacteria or fungi to foster degradation and removal of pollutants. The development of the third model for determining the mobility and growth of bacterial microorganisms are presented. This model captures three major propagation mechanisms in unsaturated soils, including natural diffusion, bacterial growth and convective flow. By adding relationship between pollutant degradation rate and bacteria concentration, the fourth model was applied to study the bioremediation remediation of petroleum pollution. Finite element method was conducted to solve mathematical models, which are partial differential equations of high nonlinearity. Based on computational results from the fist model, concentrations of various pollutants for both inorganic and organic can be predicted at any interested time in different types of soils under various environmental conditions. The second and fourth models can be used as numerical tools, which greatly facilitate the designing and evaluation of cleaning efficiency and effectiveness of electrokinetic remediation and bioremediation schemes, respectively.
M.S. in Civil, Architectural and Environmental Engineering, May 2015
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Title: THERAPEUTIC MISCONCEPTION AMONG PARTICIPANTS OF THE DOBELLE VISION IMPLANT PROJECT
Creator: Nitsch, Kristian P.
Date: 2015, 2015-05
Description: Therapeutic misconception, as first described by Appelbaum, Roth, and Lidz (1982) is said to occur when a participant who is engaged in...
Show moreTherapeutic misconception, as first described by Appelbaum, Roth, and Lidz (1982) is said to occur when a participant who is engaged in research, erroneously conflates the purpose and goals of a given research project with those of therapeutic treatment and personal care. Therapeutic misconception is considered ethically intolerable in research as its presence is thought to undermine the process of voluntary informed consent (Appelbaum, Roth, Lidz, Benson, and Winslade, 1987). Extensive literature suggests that therapeutic misconception is a common phenomenon which occurs within a variety of research domains, and may be present in approximately 62% of research participants (Appelbaum, Lidz, & Grisso, 2004). Despite this alarming prevalence, the possibility of therapeutic misconception in neural interface research, especially projects exploring artificial vision restoration, has received little attention. Vision prosthetic trials may be particularly susceptible to engendering therapeutic misconceptions among participants, due to the intense desire to restore visual functioning, the complexity of this research context, and the dearth of information available concerning vision prosthetic devices. As a mounting number of visual neural prosthetic projects advance and reach the threshold of human-subjects research, assessing for therapeutic misconception will become increasingly essential to ensure that participants fully comprehend the nature of their involvement. The present study, which represents the first known investigation into the potential of therapeutic misconception in artificial vision research, employs semi-structured interviews and qualitative deductive content data analyses to explore the possibility that therapeutic misconception was evident, and operating, among participants of the Dobelle Vision Implant Project.
M.S. in Psychology, May 2015
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