Digital Commons Network^™

Effect Of Initial Conditions On Molecular Mixing In A High Schmidt-Number Rayleigh-Taylor Mixing Layer, Lakshmi Ayyappa Raghu Mutnuri

Masters Theses

"Characterizing molecular mixing in Rayleigh-Taylor instability (RTI) driven flows where the density and velocity fields are coupled is essential for developing exacting predictive models. Sensitivity of the Rayleigh Taylor mixing layer to initial conditions is a topic that is being explored extensively in interests of accurate turbulent mix model development and its direct consequence in various applications like design of inertial confinement fuel capsule and atmospheric modeling. As part of the current work, an experimental investigation of the effect of initial conditions on molecular mixing in a low Atwood number(~7.5 x 10⁻⁴), high Schmidt number(~1000), RTI driven mixing layer is …

A Framework For Transparent Depression Classification In College Settings Via Mining Internet Usage Patterns, Raghavendra Kotikalapudi

Masters Theses

Depression is a serious mental health problem affecting the mind and body of people in our society. As of today, depression affects about 5 to 7% of the American population, which roughly translates to 14 million people! A particularly worrying concern these days is the increasing incidence of depression among college students. The problem is so severe that many US campuses have dedicated centers with mental health professionals catering to students needs. Although there are very effective treatments for depression, studies report that ~80% of depressed students do not seek any help due to the lack of perception of the …

Bi-Harmonic Atomic Force Microscopy, Santosh R. Kodandarama

Masters Theses

"In tapping mode atomic force microscopy, surface features are measured indirectly via the amplitude of the tapping cantilever. A change in surface profile is detectable only if it results in an amplitude change that is significant enough to be measured by the optics. Previous works have focused on improving sensitivity through the system's Q-factor, either by changing physical cantilever properties or using feedback control, but those approaches undesirably slow down the dynamic response. In this work we take a novel approach to sensitivity amplification by reshaping the tapping trajectory. By shaping the trajectory so that the probe spends a greater …

Model Based Diagnostics And Prognostics Of Practical Industrial Systems, Raja Sekhar Kraleti

Masters Theses

"In this thesis, the diagnosis and prognosis of single and simultaneous multiple incipient faults in practical industrial systems is demonstrated in two papers. For the purpose of fault detection and failure prediction, a model based strategy is adopted, which involves using an online adaptive estimator. The online estimator estimates the system dynamics. Residual is generated based on the physical system model and the estimated system dynamics. This residual is used to detect the fault. Once the fault is detected, a tunable nonlinear neural network online approximator in discrete-time (OLAD) along with a robust adaptive term is initiated. The OLAD utilizes …

Educational Robotics: Using The Lego Mindstorms Nxt Platform For Increasing High School Stem Education, Matthew Aaron Strautmann

Masters Theses

"The field of educational robotics (ER) seeks to use the building and programming of robots to engage and educate the next generation of college freshman entering science and engineering majors. To increase the rate of application to science and engineering degree programs as well as the rate of retention, students must be engaged in high school. They must acquire the knowledge and interest to pursue these career choices. This research explores the use of robotics to interest high school students in science, technology, engineering, and math (STEM) and to improve their knowledge of these subjects. The case study developed instructional …

Isolation And Characterization Of Bacterial Symbionts From Crotalaria Spectabilis Grown On Trichloroethene Contaminated Soil, April Lyn Rocha

Masters Theses

"The discovery of several members of the Leguminosae family growing on a TCE contaminated site demonstrated that they have the capabilities to tolerate the TCE contamination. This led to an investigation of the plants' ability to metabolize TCE. Research by Dr. Lee Newman showed that nodules from Crotalaria spectabilis grown on the site had TCE metabolites present while nodules from other legumes at the site did not. The presence of TCE metabolites within the C. spectabilis nodules suggests that the bacterial symbiont may be responsible for TCE metabolism. This led us to investigate the symbiont of C. spectabilis and its …

Illinois State University Annuitants Association Newsletter, December 2011, Illinois State University, Annuitants Association

ISUAA News

Illinois State University Annuitants Association newsletter

Integrated Reliable And Robust Design, Gowrishankar Ravichandran

Masters Theses

"The objective of this research is to develop an integrated design methodology for reliability and robustness. Reliability-based design (RBD) and robust design (RD) are important to obtain optimal design characterized by low probability of failure and minimum performance variations respectively. But performing both RBD and RD in a product design may be conflicting and time consuming. An integrated design model is needed to achieve both reliability and robustness simultaneously. The purpose of this thesis is to integrate reliability and robustness. To achieve this objective, we first study the general relationship between reliability and robustness. Then we perform a numerical study …

Social Network Analysis Of The Video Bloggers' Community In Youtube, Anusha Mogallapu

Masters Theses

"This research studied the structure of the social network of the video blogger community on YouTube. It analyzed the social network structure of friends and subscribers of the 187 video bloggers on YouTube and calculated the social network measures. This thesis compares the results to the structure described by Warmbrodt et al. in 2007 and explains the reasons for the distinctions. The number of video bloggers has increased enormously, and the form of their interactions has changed. As a result, the video blogger social network has evolved from a core/periphery structure to one that is centralized. This indicates that the …

An Incentive Based Approach To Detect Selfish Nodes In Mobile P2p Network, Hemanth Meka

Masters Theses

"The growth of mobile devices led to the wide use of Mobile P2P networks. These networks are used in a wide variety of areas and hence there is lot of research in the field of mobile networks. Detecting selfish nodes is one of the research topics triggered due to the popularity of mobile P2P networks. It is necessary to detect selfish nodes in such networks to improve the efficiency of the network. In this thesis, an incentive based approach to detect selfish nodes is designed and evaluated. This approach differs from the existing work as it (i) can be used …

Multiple-Input Multiple-Output System Simulation For Spinning Vehicles, Samuel James Petersen

Masters Theses

"This paper investigates the performance of a multiple-input multiple-output (MIMO) wireless communication system, when the transmitter is located on a spinning vehicle. In particular, a 2x2 MIMO system is used, with Alamouti coding at the transmitter. Both Rayleigh and Rician statistical models are considered in this paper and are combined with a deterministic spinning model to simulate the channel. The spinning of the transmitting vehicle, relative to the stationary receive antennas causes additional signal fading, and complicates the decoding and channel estimation. The simulated bit error rate is the primary performance metric used. A 4x2 asymmetric Alamouti coding scheme is …

Field Programmable Gate Array Based Multiple Input Multiple Output Transmitter, Richa Shekhar

Masters Theses

"MIMO is an advanced antenna technology compared to Single Input Single output (SISO), Multiple Input Single Output (MISO), and Single Input Multiple Output (SIMO) and is used to obtain high data rate in the system. Multiple-Input Multiple-Output (MIMO) systems have at least two transmitting antennas, each generating unique signals. However some applications may require three, four, or more transmitting devices to achieve the desired system performance. This thesis describes a comparison between different approaches like the microcontroller, ASICs and the FPGA available in the market for baseband signal generation. It also describes the design of a scalable MIMO transmitter, based …

Uncertainty Quantification Integrated To Computational Fluid Dynamic Modeling Of Synthetic Jet Actuators, Srikanth Adya

Masters Theses

"The Point Collocation Non-Intrusive Polynomial Chaos (NIPC) method was applied to a stochastic synthetic jet actuator problem to demonstrate the integration of computationally efficient uncertainty quantification to the high-fidelity CFD modeling of Synthetic Jet Actuators. The uncertainty quantification approach was first implemented in two stochastic model problem cases for the prediction of peak exit plane velocity using a Fluid Dynamic Based analytical model of the Synthetic Jet Actuator, which is computationally less expensive than CFD simulations. The NIPC results were compared with direct Monte Carlo sampling results. To demonstrate the efficient uncertainty quantification in CFD modeling of synthetic jet actuators, …

Towards On-Line Voltage Stability Assessment Using Synchrophasors, Himanshu Subandhu Hirlekar

Masters Theses

"Voltage instability has become a growing concern in the operation of power systems in recent years. The reason is that power systems all over are being operated with reduced margins because of increased demand exacerbated by a general reluctance to invest in improvement of the electric grid infrastructure. Until recently it was difficult to predict voltage instability in the on-line environment. However, advances in technology has made possible the on-line monitoring and assessment of voltage stability. Synchrophasors is a relatively new technology in the field of power systems which allows system operators to monitor the system conditions at specific measurement …

Crack Formation In Investment Casting Ceramic Shells, W. A. Everhart

Masters Theses

"This thesis is a collection of papers that discuss shell cracking in investment casting during pattern removal. The application of rigid polymeric foam for large investment casting patterns with complex geometries can improve the dimensional tolerances and the surface quality of the casting. However, these pattern materials have a tendency to promote crack formation in investment casting shells during pattern removal by firing.

The first two papers discuss the factors affecting shell cracking and methods to prevent it. Experimental methods were combined with finite element modeling to predict stress in the shell. A 3D nonlinear finite element model was developed …

A Neural Network Based Approach For Path Planning On Costmap, Songjie Chen

Masters Theses

"In this thesis, a path planning method using a three-level hierarchical system model is proposed. In the top level of the hierarchy, the given location points to visit are taken as waypoints. The waypoint navigation process is formulated as a traveling salesman problem (TSP). The Lin-Kernighan algorithm is used to solve the TSP and transfer the solution to the lower level of the hierarchy. In the middle level, the path is represented by a grid-based costmap. A novel modified Grossberg neural network is designed to solve the point-to-point path planning. The bottom level of the hierarchy smoothens the path with …

A Statewide Analysis Of Highway Safety In Arkansas, Uday R. R. Manepalli

Masters Theses

"This research concentrated on two major aspects of highway safety analysis, hotspot identification and identification of crash contributing factors on highways. The objective of the first part of this thesis is to evaluate two crash frequency, three crash severity and two composite hotspot ranking methods. Based on the limitations of the existing hotspot identification methods (HSID), crash factor method (CFM), a crash severity based HSID method is proposed. A composite rank method (F 1) based on principal component analysis is also proposed. These methods are evaluated using three tests, the site consistency test, the method consistency test, and the total …

Grid Frequency And Voltage Support Using Photovoltaic Systems With Energy Storage Assist, Ravi Bhatt

Masters Theses

"An optimized operating scheme for a grid-connected community based photovoltaic (PV) system is described. The system can participate in grid ancillary services like frequency and voltage regulation functions based on the Smart Grid framework. The proposed model comprises of a PV plant with Li-ion batteries coupled to the grid by means of a three-phase inverter. A two-way communication between the PV plant and the grid is assumed. The PV/storage plant provides constant updates on its current kW/kVar capability and the grid transmits the demand for specific amounts of power and for specific lengths of time. The battery charging energy can …

Inherent And Model-Form Uncertainty Analysis For Cfd Simulation Of Synthetic Jet Actuators, Daoru Frank Han

Masters Theses

"A mixed aleatory (inherent) and epistemic (model-form) uncertainty quantification (UQ) analysis method was applied to a computational fluid dynamics (CFD) modeling problem of synthetic jet actuators. A test case, (Case 3, flow over a hump model with synthetic jet actuator control) from the CFDVAL2004 workshop was selected to apply the Second-Order Probability framework implemented with a stochastic response surface obtained from Quadrature-Based Non-Intrusive Polynomial Chaos (NIPC). Three uncertainty sources were considered: (1) epistemic uncertainty in turbulence model, (2) aleatory uncertainty in free stream velocity and (3) aleatory uncertainty in actuation frequency. Uncertainties in both long-time averaged and phase averaged quantities …

The Sorption Of Chemical And Nuclear Contaminants From Soil And Water Using Nanosize Particles Of Hydroxyapatite, Chyrene Joseph

Masters Theses

"High surface area (>200 m²/g) crystals composed of nanosize (30-50nm) hydroxyapatite; (Ca₅(PO₄)₃OH) particles are being investigated as an alternative in cleaing [sic] contaminated groundwater and soil by removing toxic wastes and radionuclides. Static batch tests were carried out at 2, 4, 8, 24 and 120 hour time periods by reacting hydroxyapatite with individual solutions prepared with specific elements to evaluate the applicability of hydroxyapatite in removing potential contaminants. Chemical analyses on leachant solutions, leachate solutions, and post-reaction digested solids were conducted by Inductively Coupled Plasma-Mass Spectroscopy to determine the extent of ion removal. Removal of these ions is expected …

Characterization Of Shielding Effectiveness For Metallic Enclosures, Nicholas Bennett Mentesana

Masters Theses

"This topic discusses and verifies an equation for estimating the shielding effectiveness of metallic enclosures through the use of numerical simulations. Using ideas from Bethe's "Theory of Diffraction by Small Holes", a previous student from the Missouri S&T Electromagnetic Compatibility Laboratory developed an equation that would yield an envelope prediction for the worst-case EMI from an aperture array backed by an over-moded cavity. Min Li (PhDEE '99) used results from measurements, simulations, and physics-based equations to formulate a simple equation that would predict these EMI levels. The main purpose of this thesis is to revisit this work and determine when …

Morpho-Tectonic Analysis Of The Tekeze And The Blue Nile Drainage Systems Of Northwestern Ethiopian Plateau, Ethiopia, Elamin Hassan Dai Ismail

Masters Theses

"This study examines the morpho-tectonic evolution of the drainage system in the northwestern Ethiopian plateau by focusing on the Tekeze and the Blue Nile Rivers. The plateau is underlain by Precambrian crystalline rocks, overlain by Mesozoic sedimentary section that is topped with a 1-3 km thick pile of Oligocene-Quaternary volcanic rocks. It is bounded in the east and southeast by the Afar Depression (AD) and the Main Ethiopian Rift (MER). Satellite derived Digital Elevation Models are analyzed using ArcGIS and RiverTools to extract morpho-tectonic parameters of tributaries of the Tekeze and Blue Nile Rivers including Normalized Steepness Index (K_{sn …}

Computational Investigation Of Plasma Actuator As An Active Flow Control Strategy Of Laminar Separation Bubbles, Justin Roger Aholt

Masters Theses

"A parametric computational study designed to examine the plausibility of an external body force generated by active means, such as a plasma actuator, as a means of controlling a Laminar Separation Bubble (LSB) over an airfoil at low Reynolds numbers was conducted. Computational Fluid Dynamics (CFD) was employed to characterize the effect that a body force, localized to a small region tangent to the airfoil surface, might have on an LSB. In this study, the effects of altering the strength and location of the "actuator" on the size and location of the LSB and on the aerodynamic performance of the …

Analysis And Modeling Of Depth-Of-Cut During End Milling Of Deposited Material, Haythem Gaja

Masters Theses

"This study addresses depth-of-cut detection and tool-workpiece engagement using an acoustic emission monitoring system during milling machining for a deposited material. Online detection of depth-of-cut presents many technical difficulties. Researchers have used various types of sensors and methods to assess the depth-of-cut and surface errors. Due to the strong correlation between acoustic emission and cutting depth during the depth end milling process, it is useful to forecast the depth-of-cut from the acoustic emission signal. This work used regression analysis to model and detect the depth-of-cut. The experiments were carried out on a Fadal vertical 5-Axis computer numerical control machine using …

Meloc - Memory And Location Optimized Caching For Mobile Ad Hoc Networks, Lekshmi Manian Chidambaram

Masters Theses

"The advancement of Mobile ad hoc networks (MANET) is tremendous in the field of social and military applications. Caching and Replication are the two common techniques used to improve data access efficiency in Mobile Ad hoc networks. Caching favors data access efficiency by bringing data closer to the source. Existing caching approaches are deficient in reducing the number of cache locations, thus reducing the number of copies, which is needed for many mission critical applications considering safety and security. Conversely, reducing the number of caches should not affect the efficiency of data access. We design an efficient broker based caching …

Contrast Enhancement Of Digital Mammography Based On Multi-Scale Analysis, Muhammad Imran Khan Abir

Masters Theses

"A contrast enhancement algorithm is developed for digital mammograms aiming to assist radiologists in discerning early breast cancer easily. The algorithm is based on a Laplacian pyramid framework image processing technique. The mammogram is decomposed into three frequency sub-bands, low, mid, and high frequency sub-band images. The lower sub-band image contains very fine details and higher level contains coarser features. In this method contrast enhancement is achieved from high and mid sub-bands by decomposing the image based on multi-scale Laplacian pyramid and enhance contrast by image processing. Several mapping functions are applied on sub-band images based on experimental analysis. After …

Evaluating The Effectiveness Of Multi-Spectral Remote Sensing Data For Lithological Mapping In Arid Regions: A Quantitative Approach With Examples From The Makkah Neoproterozoic Region, Saudi Arabia, Nawwaf Awad Al Muntshry

Masters Theses

"This work quantitatively evaluates the effectiveness of multi-spectral remote sensing data for geological mapping in arid regions. For this, Landsat Thematic Mapper (TM) data covering part of the Neoproterozoic Arabian Shield around the Makkah region in Saudi Arabia are used. The Makkah region is dominated by a variety of layered and intrusive rocks covered by unconsolidated sediments. The Landsat TM data have six spectral bands in the visible and near infrared (VNIR) and shortwave infrared (SWIR) with thirty meters spatial resolution.

The Optimum Index Factor (OIF) has been computed to determine the best Red-Green-Blue (RGB) band combination emerging from the …

Design Of A Current Probe For Measuring Ball-Grid-Array Packaged Devices, Tianqi Li

Masters Theses

"A current probe to measure BGA ball currents via magnetic induction has been designed. The probe is manufactured on a 4 layer flex circuit and has been validated by full wave simulations and measurements. The feature size of the probe is very tiny that it almost pushes the limit of flex-circuit technology. Several critical manufacturing problems were happened, and they have been solved now. The probe allows measuring currents of a 1 mm pitch BGA ball directly. Its operating frequency stretched from tens of MHz up to 3GHz. The BGA probe's mutual inductance is approximately 11 pH, and with amplifiers …

Influence Of Particle Size And Specimen Preparation On The Iowa Pore Index, Christopher Paul Davis

Masters Theses

"This study was performed in order to identify a size correction that would allow aggregate of different sizes, other than the standard 1/2-3/4-inch fraction, to be used in the Iowa Pore Index (IPI) test. This size correction would allow for the IPI to be determined for aggregate gradations of material that have a nominal maximum size (NMS) smaller than 3/4-inch. The interest in a size correction for the IPI developed from its use in a Durability Factor (DF) estimation equation. The estimation equation was developed with the use of 19 different DF from Missouri aggregate sources, where eight aggregates had …

Development Of A Vessel Mimicking Material For Use In Anatomically Realistic Doppler Flow Phantoms, Deirdre King, Carmel Moran, John Mcnamara, Andrew Fagan, Jacinta Browne

Articles

Polyvinyl alcohol cryogel, (PVA-C) is presented as a vessel mimicking material for use in anatomically realistic Doppler flow phantoms. Three different batches of 10 % wt PVA-C containing (i) PVA-C alone, (ii) PVA-C with anti-bacterial agent and (iii) PVA-C with silicon carbide particles were produced, each with 1 to 6 freeze-thaw cycles. The resulting PVA-C samples were characterized acoustically (over a range 2.65 - 10.5 MHz) and mechanically in order to determine the optimum mixture and preparation for mimicking the properties of healthy and diseased arteries found in vivo. This optimum mix was reached with the PVA-C with anti-bacterial agent …