Digital Commons Network^™

Process Planning And Control Of Functionally Graded Parts Using Freeze-Form Extrusion Fabrication, Bradley Kenneth Deuser

Masters Theses

"Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing technology that is capable of fabricating complex three-dimensional parts. FEF works by depositing an aqueous-based colloidal ceramic or metal paste in a layer-by-layer fashion below the freezing point of the aqueous medium as to rapidly freeze the paste. The FEF machine in the present study is equipped with three syringes and is capable of mixing each paste in a desired composition ratio by using an inline static mixer. Compensation for the transport delay caused by the static mixer is necessary; therefore, an algorithm was developed to apply a one-dimensional (1D) composition gradient …

Analysis Of Optimal Control Derivations For Aerial Defense, Andrew John Friedrichs

Masters Theses

"Optimal control will be used to derive four guidance laws for the purpose of defending an aircraft from incoming missiles. The dynamics of the defending missile, and the overall engagement are used in these derivations. They are evaluated first in two degrees of freedom, then in six degrees. The guidance objective is to move a defending missile between the aircraft and the attacker. Optimal control is used to derive different commanded accelerations. Utilizing small changes in the cost functions, four applications will be derived. Triangle Guidance is used for inspiration, and initially a direct approach is attempted. In the course …

Automatic Detection Of Annular-Granular Patterns In Melanoma In Situ Dermoscopy Images, Parivash Hajiyani

Masters Theses

"Early detection of malignant melanoma greatly benefits patients, as the overall success is dependent on finding these melanomas before they reach the invasive stage. Dermoscopy is a non-invasive skin imaging technique that studies have shown can improve the diagnostic accuracy of dermatologists by as much as 30% over clinical examination. In this project machine vision and image analysis techniques are used to detect annular granular areas in dermoscopy images automatically. The proposed algorithm utilizes the luminance ratio between annular and granular areas within the darkest 30% of the lesion. All points whose luminance value are less than 30% of the …

Coaxial Cable Bragg Grating, Jie Huang

Masters Theses

"In order to ensure the continued safe and reliable operation of various civil structures, such as dams, bridges, and buildings, in situ strain monitoring is of great importance, especially for structures that may experience large strains. A new coaxial cable Bragg grating (CCBG) is developed as a strain sensor and the sensor's capacity for large range strain measurement is demonstrated for the first time. The sensor device is comprised of regularly spaced periodic discontinuities along a coaxial cable. The discontinuities are fabricated using a computer numerical controlled (CNC) machine to drill holes in the cable. Each discontinuity generates a weak …

Microstructure And Mechanical Properties Of Silicon Carbide-Titanium Diboride Ceramic Composites, Derek Scott King

Masters Theses

"The microstructure, hardness, fracture toughness, Young's modulus, strength and Weibull modulus of silicon carbide-titanium diboride (SiC-TiB₂) ceramics were studied. First, SiC-TiB₂ ceramics with 15 vol.% TiB₂ particles were processed using two green processing methods, spray drying (ST) and ball milling (SiC-15TiB₂). In addition, SiC-TiB2 ceramics with TiB₂ contents ranging from 0 to 100 vol.% were produced to determine a TiB₂ content that produced the best combination of mechanical properties. From spray drying, segregation of the TiB₂ particles in ST led to a granule-like microstructure and spontaneous microcracking in the final ceramic. In ceramics containing 20 and 40 vol.% TiB₂, the …

Methods Of Optimizing The Gas Exchange Process To Improve Fuel Efficiency Of Small Carbureted Spark Ignition Engines, Cory Hannibal Huck

Masters Theses

"Fuel efficiency of internal combustion engines long has been a topic of concern. Much effort has been made to optimize the fuel efficiency of large automotive type engines. However, for small engine manufactures subject to tight cost constraints, this has only recently become an area of great focus. A method by which the fuel efficiency of an engine can be improved is through optimization of the intake process. Specifically, reductions in flow losses and the choice of appropriate valve event timings can provide ways to make gains towards more fuel efficient operation. The challenge arises when the focus is on …

On The Design Partitioning Of 3d Monolithic Circuits, Luke Maresca

Masters Theses

"Conventional three-dimensional integrated circuits (3D ICs) stack multiple dies vertically for higher integration density, shorter wirelength, smaller footprint, faster speed and lower power consumption. Due to the large through-silicon-via (TSV) sizes, 3D design partitioning is typically done at the architecture-level With the emerging monolithic 3D technology, TSVs can be made much smaller, which enables potential block-level partitioning. However, it is still unclear how much benefit can be obtained by block-level partitioning, which is affected by the number of tiers and the sizes of TSVs. In this thesis, an 8-bit ripple carry adder was used as an example to explore the …

Advanced Moisture Modeling Of Polymer Composites, Nathan Robert Roe

Masters Theses

"Composite materials absorb moisture from the environment and over time this moisture absorption affects the mechanical performance of the material. In order to determine the long-term moisture effects on the component, representative parts must be tested after having been exposed to an accelerated moisture-conditioning environment. This accelerated environment simulates the worst-case exposure conditions that a part might experience. Currently accepted methodologies for analyzing the time required to condition specimens are limited, only allowing simple geometry and an assumption that diffusivity rates are independent of the flow path or direction. Therefore, a more advanced finite element method is desired. In the …

Driver Mandatory Lane Change Behavior: Use Of Governing Gap In Critical Gap Estimation, Srinadh Kandada

Masters Theses

"This study analyzed the driver gap acceptance and rejection behavior during mandatory lane changes on a multilane freeway in congested and uncongested traffic conditions. During a lane change, drivers were more receptive to either the leading or the trailing gaps with vehicles in the target lane which governed the drivers' lane change and is termed as the governing gap. Drivers maneuvered till the governing gap was greater than the critical gap, accepted the gap and made a lane change. In this process, drivers reduced the non-governing gap to increase the length of the governing gap. The drivers as a result …

Experimental Feasibility Study Of A Passive Radio Frequency Identification-Based Distributed Beamforming Framework And Radio Frequency Tag Design For Achieving Dynamic Beamforming, Pratim Shah

Masters Theses

"Passive UHF RFID tags works on the principle of backscattering mechanism. In realistic environment, there are multiple objects and tags that create complex, multipath propagation scenarios with numerous null-points, reduced read range and read rate.

In general, the RF frontend of tags could be controlled such that the negative effects of multipath propagation are reduced or even inverted thus implementing a virtual beamforming. The theoretical framework of beamforming in RFID system, using additional tags as virtual antenna arrays, has been discussed before. The presented study evaluates the feasibility of such beamforming in passive RFID systems. Moreover, it synthesizes an appropriate …

Benign Intracranial Hypertension: A Diagnostic Dilemma, Gary Y. Shaw, Stephanie K. Million

Student Publications

Benign intracranial hypertension (BIH) (also known as pseudotumor cerebri and empty sella syndrome) remains a diagnostic challenge to most physicians. The modified Dandy criteria consist of, the classic findings of headache, pulsatile tinnitus, papilledema, and elevated cerebrospinal fluid (CSF) pressure, however, these are rarely collectively present in any one patient. Furthermore, these findings can wax and wane over time. Due to the nature of this disease, both signs and symptoms may be intermittent, making definitive diagnosis difficult. Newer imaging studies, particularly the magnetic resonance venogram (MRV) along with a constellation of correlative findings and associated diseases have given new impetus …

Pulmonary Fluid Dynamics And Aerosol Drug Delivery In The Upper Tracheobronchial Airways Under Mechanical Ventilation Conditions, Timothy Andrew Van Rhein

Masters Theses

"The effects of mechanical ventilation conditions on fluid flow and particle deposition were studied in a computer model of the human airways. The frequency with which aerosolized drugs are delivered to mechanically ventilated patients demonstrates the importance of understanding the effects that ventilation parameters have on particle deposition in the human airways. Past studies that modeled particle deposition in silico frequently used an idealized geometry with steady inlet conditions. With recent advancements in computational power and medical imaging capabilities, studies have begun to use more realistic geometries or unsteady inlet conditions that model normal breathing. This study focuses specifically on …

A Decentralized Fault Diagnosis And Prognosis Scheme For Nonlinear Interconnected Systems, Deepthi Shreeya Lathamaheswari Raja

Masters Theses

"Today's systems are getting more complex with a significant number of variables to be monitored for information processing to aid in fault diagnosis and prognosis. Centralized diagnosis and prognosis schemes are not preferred for such complex systems as they lead to delayed or missed alarms and possibly catastropic [sic] failures. Instead, this thesis addresses a decentralized fault diagnosis and prognosis scheme both in continuous and discrete-time for nonlinear complex systems which can be divided into smaller subsystems. Such complex systems are referred to as a large-scale interconnected nonlinear system. This thesis is presented in the form of two papers first …

Hot Channel Determination And Burnup Analysis Of Missouri University Of Science And Technology Research Nuclear Reactor, Kelly Christopher Rogers O'Bryant

Masters Theses

"A burnup analysis has been performed on the Missouri University of Science and Technology (Missouri S&T) Research Nuclear Reactor (MSTR). With use of the Monte Carlo neutronics depletion code MCNPX, burned material was input into a neutronics model (burned model) in order better simulate MSTR core characteristics. Simulated burnup values of ²³⁵U for the past twenty years of MSTR operations totaled 14.266 grams, slightly less than the 14.527 grams reported by the reactor staff. A distribution of ²³⁵U was simulated and a burnup map was developed.

Using the updated fuel material, the hot channel of the current configuration of the …

Lattice Residuability, Philip Theodore Thiem

Masters Theses

"Residuated lattices form the basis of certain kinds of logical interpretations. Also, complete commutative integral zero-bounded residuated lattices are used as a set of truth values for fuzzy logic values, Which are more general than the traditional bounded interval introduced by Zadeh. At times, it is important to know whether or not the lattice can be residuated in the first place. This thesis reviews the literature in lattice residuability and adds more observations. Specifically, (1) bounded chains and top-residuated lattices are show [sic] to be residuable, and (2) additional conditions necessary for residuability are established"--Abstract, page iii.

Distributed And Collaborative Watermarking In Relational Data, Prakash Kumar

Masters Theses

"Watermarking relational data is an important topic in the field of copyright protection, given the increasing prevalence of piracy and illegal duplication of databases. While there exists solutions for watermarking relational data, the problems that arise due to multiple ownership (two or more) of databases have not been acknowledged. This research focuses on developing a novel watermarking scheme to counter the problems. The watermarking scheme proposed necessitates the owners of the database in consideration to come together to perform the watermarking process. The scheme can be applied to insert watermarks in both numerical and categorical data. The watermarking scheme is …

Displacement Of Heavy Oil By Carbon Dioxide In A Tube, Mohammed Almabrouk Ali Ahmad

Masters Theses

"After using primary and secondary oil recovery methods, about two third of the original oil in place is left behind in the reservoir. Enhanced oil recovery (EOR) methods are being used to recover that oil. CO₂ flooding is one of the EOR methods that is used to recover the oil. The interest here lies in recovery of heavy oils. The dissolution of CO₂ in oil reduces oil viscosity and swells it, making it easier to displace the oil. FLUENT is used to solve the problem of CO₂ displacing heavy oil in a tube. Different velocities/capillary numbers (Ca) and …

Bond Behavior Of High-Volume Fly Ash And Self-Consolidating Concrete, Trevor Jay Looney

Masters Theses

"The main objective of this study was to determine the effect on bond performance of high-volume fly ash (HVFA) concrete and self-consolidating concrete (SCC). The HVFA concrete test program consisted of comparing the bond performance of two concrete mix designs with 70% cement replacement with Class C fly ash relative to a Missouri Department of Transportation (MoDOT) standard mix design. The SCC test program consisted of comparing the bond performance of normal and high strength SCC with their respective MoDOT standard mix designs.

Two test methods were used for bond strength comparisons. The first was a direct pull-out test based …

Capture Zone Modeling For Photovoltaic Microgrid Powered Pump And Treat Remediation, John Patrick Conroy

Masters Theses

"Remediation systems protect human health and the environment by removing harmful contaminants from the environment. Pump and treat groundwater remediation systems typically rely on utility power to continuously pump contaminated groundwater to an above ground treatment unit. However, the use of renewable energy (solar and wind) for a pump and treat remediation system can reduce the output of harmful greenhouse gases and the need for coal-based utility power.

This paper describes a hypothetical renewable energy powered pump and treat remediation system that uses an off-grid photovoltaic array to power a submersible solar water pump. The pump operates on an intermittent …

A Comparison Of Near-Infrared And Visible Imaging For Surveillance Applications, Kathryn Nicole Rodhouse

Masters Theses

"A computer vision approach is investigated which has low computational complexity and which compares near-infrared and visible image systems. The target application is a surveillance system for pedestrian and vehicular traffic. Near-infrared light has potential benefits including non-visible illumination requirements. Image-processing and intelligent classification algorithms for monitoring pedestrians are implemented in outdoor and indoor environments with frequent traffic. The image set collected consists of persons walking in the presence of foreground as well as background objects at different times during the day. Image sets with nonperson objects, e.g. bicycles and vehicles, are also considered. The complex, cluttered environments are highly …

Integration Of Multiple Vision Systems And Toolbox Development, Rohit Vijay Bapat

Masters Theses

"Depending on the required coverage, multiple cameras with different fields of view, positions and orientations can be employed to form a motion tracking system. Correctly and efficiently designing and setting up a multi-camera vision system presents a technical challenge. This thesis describes the development and application of a toolbox that can help the user to design a multi-camera vision system. Using the parameters of cameras, including their positions and orientations, the toolbox can calculate the volume covered by the system and generate its visualization for a given tracking area. The cameras can be repositioned and reoriented using toolbox to generate …

Identification Of Starry Milia-Like Cysts In Seborrheic Keratoses And Malignant Melanomas Using Image Processing Techniques, Viswanaath Subramanian

Masters Theses

"Seborrheic keratoses are the most common benign tumors found in older individuals. Seborrheic keratoses are normally benign in nature, but sometimes in a large lesion area of seborrheic keratoses, secondary tumors, or squamous cell carcinoma in situ or malignant melanoma may occur. It has been found that seborrheic keratoses have a few features that distinguish them from melanomas. Milia-like cysts, comedo-like openings and network-like structures are the most prominent features found in seborrheic keratoses. Comedo-like openings are pigmented structures and are mostly oval yellowish, brown or black in appearance. They can also be observed in melanocytic lesions and melanomas. Milia-like …

Studies Of Inductive Plasmas And Their Application To Theta-Pinch Devices Via Numerical Modeling, Warner C. Meeks

Masters Theses

"First, a globally-averaged RF plasma model is used to investigate exit conditions immediately following a RF pre-ionization stage. Analysis shows that reducing pulse duration from 10⁻⁶ to 10⁻⁷ seconds increases peak ion energy fraction by 17% (from 16 to 33%) and doubles final conductivity. Pulse waveforms are square in nature, and ion energy fraction is defined in this work as the percentage of total input energy entrained in ions. Increasing total energy deposition from 5 to 160 mJ increases ion energy fraction from 33% to 58% at a 200 ns pulse duration. This increase is not linear however, showing instead …

Modeling Supply Chain Network Resiliency In The Aftermath Of An Extreme Event, Varun Ramachandran

Masters Theses

"Failure of infrastructure elements due to an extreme event adversely affects the supply chain networks in any urban environment. This study models the resiliency of a supply chain network by integrating geospatial data with critical supply chain elements and graph theory. This model can then be combined with an extreme event simulation to calculate resiliency. Resiliency refers to the time required for services and select economic indicators to approach pre-event levels (in this study, a return to 80% of the pre-event capacity). This research proposes an interdisciplinary approach to develop a comprehensive framework for resiliency modeling. This approach includes the …

Intelligent Energy Management And Demand-Response Control For A Photovoltaic-Battery System, Yang Liu

Masters Theses

"The work shown in this thesis is to develop an intelligent energy management and demand-response controller (IEMDC) for a photovoltaic-battery (PVB) system with a programmable load. Specifically, the research work related to this issue focuses on the modeling and real-time simulation of a microgrid with an emphasis on photovoltaic, battery and programmable load and the development of an energy management controller for optimally dispatching the power from the PVB system to the loads. The IEMDC is used for daytime grid-independent operation. The energy management controller is based on fuzzy logic controller (FLC) whose membership functions are optimized using mean-variance optimization …

Design And Verification Of Clockless Advanced Encryption Standard (Aes) Crypto-Hardware For Improved Side-Channel Attack Resistance, Siva Pavan Kumar Kotipalli

Masters Theses

"The Advanced Encryption Standard (AES) is the most widely used symmetric key algorithm standard in different security protocols. The AES was very reliable in providing security for data until a few years ago, when researchers proved the Side Channel Attacks (SCA) like power analysis were successful in compromising this security.

This thesis focuses on designing effective countermeasures against the SCA's, by exploring the usage of an Asynchronous logic based design approach, called Null Convention Logic (NCL). This work discusses the design of NCL based subset of AES cryptosystem. The performance benefits of this novel cryptosystem are presented by making qualitative …

Implementation And Evaluation Of Spatial Audio Recording And Rendering Techniques, Jayasecha Raghavendra Nimmala

Masters Theses

"The thesis is divided into two main sections. First half describes the implementation of different adaptive beamforming techniques. Adaptive beamforming techniques are widely used in many real world applications like teleconferencing, speech recognition, devices for the hearing impaired, radar, sonar, etc. The beamformer is an array of sensors which can be electronically steered to any particular direction to enhance the signal in the direction of interest while at the same time suppressing interference or jammers coming from other directions.

In our experiment, we implement both the regularized minimum variance distortionless receiver (MVDR) and the generalized sidelobe canceller (GSC). The beamforming …

Microlens Array Light Trapping In Cdte/Cds Solar Cells, Patrick Michael Margavio

Masters Theses

"In light of the continued rise in fossil fuel costs, alternative energy sources, such as solar technology, are increasingly important. Concentrating photovoltaic systems are promising for future efficient and cost effective competition with fossil fuels. A microlens array is employed to a CdTe/CdS semiconducting solar cell to increase efficiency via light trapping. Since the microlens array will cause a local increase in incident light intensity, it should cause a corresponding increase in efficiency. The solar cell is deposited layer by layer. The CdS layer is chemically deposited. The CdTe layer is deposited using a novel additive manufacture technique: laser melting …

Information Theoretic Analysis And Design Of Passive Wireless Backscatter Sensor Networks, Aditya V. Padaki

Masters Theses

"Passive, backscatter-based communication technology is increasingly employed in wireless sensing applications. It offers several advantages including small form factor, battery-less operation, increased system lifetime, small configurations, etc. The main focus of this work is to study the theoretical limits of the network performance in such passive sensor networks. In addition to the traditional direct communication between an active and several passive devices (like RFID), the information theoretic analysis considers two new communication frameworks: multi-hop and multipath passive networks. These new frameworks are demonstrated through theoretical and simulation results to improve the network performance and fairness over the traditional direct communication. …

In Vivo Evaluation Of Microfibrous Bioactive Borate Glasses For Use In Wound Healing, Yinan Lin

Masters Theses

"This project consisted of two parts focused on in vivo evaluation of microfibrous bioactive borate glasses for use in wound healing. Part one of the project involved subcutaneous implantation of two types of borate glass microfibers and 45S5 glass micro fibers in the dorsum of rats and histologically evaluating the soft tissues at the implant sites at 2 to 4 weeks post surgery. The primary objective was to assess the angiogenic response to the implanted materials. The 13-93B3 and 13-93B3Cu glass microfibers were found to significantly increase the microvascular density in soft tissue, an outcome that suggests these simple and …