Engineering Commons^™

Development Of A Multiband Remote Sensing System For Determination Of Unsaturated Soil Properties, Cyrus D. Garner

Graduate Theses and Dissertations

A multiband system including active microwave sensing and visible-near infrared reflectance spectroscopy was developed to measure unsaturated soil properties in both field and laboratory environments. Remote measurements of soil volumetric water content (θv), soil water matric potential (ψ), and soil index properties (liquid limit [LL], plastic limit [PL], and clay fraction [CF]) were conducted. Field-based measurement of θv was conducted using a ground-based radar system and field measurements within 10 percentage points of measurements acquired with traditional sampling techniques were obtained. Laboratory-based, visible and near infrared spectroscopy was found to be capable of obtaining empirical, soil specific regression functions (partial …

Trihalomethane, Dihaloacetonitrile, And Total N-Nitrosamine Precursor Adsorption By Carbon Nanotubes: The Importance Of Surface Oxides And Pore Volume, Erin Needham

Graduate Theses and Dissertations

As drinking water sources become increasingly impaired, enhanced removal of natural organic matter (NOM) may be required to curb formation of disinfection byproducts (DBPs) upon chlor(am)ination. While carbon nanotubes (CNTs) can adsorb NOM, their properties for DBP precursor adsorption have not been elucidated. Nine types of CNTs were assessed for trihalomethane (THM), dihaloacetonitrile (DHAN), and total N-nitrosamine (TONO) precursor adsorption. Batch isotherm experiments were completed with lake water and, to simulate an impaired condition, effluent from a wastewater treatment plant (WWTP). Adsorption varied with CNT type and dose, with TONO precursors having the highest percent removals from WWTP effluent (up …

Effect Of Column Axial Load On Skewed Smf Rbs Connection Demands, Clovis Desrochers

Graduate Theses and Dissertations

Steel buildings in high seismic areas often require special structural systems to transfer large lateral forces induced by earthquake accelerations. The selection of an appropriate seismic steel system (braced frame, moment frame, shear wall, etc.) is often influenced by architectural considerations. Moment frame configurations offer the most architectural flexibility, but are limited by code prequalification requirements that limit the use of non-orthogonal (skewed) beam-column connection geometries. A recent study has investigated laterally skewed moment frame connections, indicating that skew increases the potential for column twist and column flange yielding; however, it is unclear how realistic column axial loads will affect …

Numerical Simulation Of Metallic Uranium Sintering, Bruce Berry

Graduate Theses and Dissertations

Conventional ceramic oxide nuclear fuels are limited in their thermal and life-cycle properties. The desire to operate at higher burnups as is required by current utility economics has proven a formidable challenge for oxide fuel designs. Metallic formulations have superior thermal performance but are plagued by volumetric swelling due to fission gas buildup. In this study, we consider a number of specific microstructure configurations that have been experimentally shown to exhibit considerable resistance to porosity loss. Specifically, a void sizing that is bimodally distributed was shown to resist early pore loss and could provide collection sites for fission gas buildup. …

Feasibility Of Using Oxide Thickness Measurements For Predicting Crack Growth Rates In P91 Steel Components, Ralph Edward Huneycutt Iv

Graduate Theses and Dissertations

There are only few methods available for predicting the age of cracks that are found in high

temperature structural components during service; among the promising ones is the oxide

thickness measurement technique. Oxide thickness profiles are taken from crack surfaces of

components and used for predicting the rates of crack propagation. This technique is particularly

suitable for high temperature components fabricated from ferritic steels commonly used in power

plants that run on fossil fuels. To implement this technique, it is necessary to fully understand the

kinetics of high temperature oxidation in these steels. In this study, the oxidation characteristics

of …

A Comparison Of Force And Pressure Coefficients On Dome, Cube And Prism Shaped Buildings Due To Straight And Tornadic Wind Using Three Dimensional Computational Fluids Dynamics, Majdi A. A. Yousef

Graduate Theses and Dissertations

Tornadoes induce very different wind forces than a straight-line (SL) wind. A suitably designed building for a SL wind may fail when exposed to a tornado-wind of the same wind speed. It is necessary to design buildings that are more resistant to tornadoes. Most studies have been conducted to investigate tornado forces on cubic, gable-roof and cylinder buildings. However, little attention has been paid to investigate tornado force on dome buildings; hence, further research is conducted in this study. The forces on a dome, cube and prisms were analyzed and compared using Computational Fluid Dynamics (CFD) for tornadic and SL …

The Intersection Of Manufacturing Technologies And School Music Programs, Leslie Prunier

University Scholar Projects

The objective of this project is to design and manufacture a musical instrument, a marching baritone horn, out of plastic. It is constructed out of both PVC pipe and 3D-printed components. Utilizing this project’s documentation, a high school student could use a 3D printer and other basic tools to make their own musical instrument for a fraction of the cost of purchasing one. This documentation will produce a horn tuned in the key of B flat with one functioning valve, and suggestions for future work to make the other two valves functional as well.

Reconfigurable All-Optical De-Multiplexing Via Spatial-Selective Frequency-Up-Conversion In Kai(2) Multimode Waveguide, Young Bong Kwon

Electrical Engineering Dissertations - Archive

We investigate spatial-mode-selective frequency up-converters in ?(2) multimode waveguides for classical and quantum communication. For the classical application, our method works as spatial-mode de-multiplexer for mode-division-multiplexing (MDM) communication system. For the quantum application, mode-selective quantum frequency conversion (QFC) enables multidimensional quantum encoding (qudits rather than qubits) which could eventually contribute to higher capacity of quantum communication links (higher QKD rates). First, we numerically investigate mode-selective up-conversion in a slab waveguide (2D free space) and periodically-polled KTP (PPKTP) waveguide. A 2D slab waveguide model is proposed based on non-collinear sum frequency generation (SFG). This model enables the calculation of conversion efficiencies …

Sparse Array For Wireless Sensor Networks And Wireless Communications, Hao Liang

Electrical Engineering Dissertations - Archive

Underwater target detection and recognition has been widely used nowadays. In this dissertation, we show that the 3-D nested-array system can provide O(N^2) degree of freedom by using only N physical sensors when the second order statistics of the received data is used, which means we can use less sensors to get a better performance. We propose a maximum likelihood (ML) estimation algorithm for underwater target size detection. Theoretical analysis illustrates that our underwater sensor network can tremendously reduce the variance of target estimation. We show that our ML estimator is unbiased and the variance of parameter estimation matches the …

Lung Nodule Detection And Segmentation Using A Patch-Based Multi-Atlas Method, Mustafa Alam

Electrical Engineering Dissertations - Archive

CT image based lung nodule detection is the most widely used and accepted method for detecting lung cancer. Most CT image based methods rely on supervised learning, which has a high number of false positives and need a large amount of pre-segmented training samples. These problems can be solved if an optimally small number of training sample images can be created, where each sample has lung nodules of similar size and shape as the target image of the actual patient. Based on this hypothesis, two algorithms are proposed for 2D CT images and 3D CT images respectively. Both algorithms use …

Multi-Object Detection And Tracking In Sensor Networks And Video Sequences, Guohua Ren

Electrical Engineering Dissertations - Archive

Firstly the problem of tracking multiple objects using observations acquired at spatially scattered sensors is considered here. Sensors are measuring a sort of signal attenuation from the present targets/sources. Multiple moving targets may die and be born at some point of the monitored period while the states of the sources, e.g. temperature of a fire source, CO/CO2 density of gas source, are also changing with time. In the case of targets tracking, radar signals sent out by sensors and later bounced back from the surface of the targets are measured at sensors, and the task is to find out the …

Gain Scheduling Controller For Aircraft With Mass And Inertia Variation, Eunyoung Kim

Mechanical and Aerospace Engineering Dissertations - Archive

Robustness is one of the main control design requirements for aircraft control.Robustness is sought in the stability and performance of closed loop system against various factors such as disturbance, measurement error, modeling error or un-modeled dynamics. In aircraft control design, it is common to assume that the mass and inertia properties of aircraft are constant. Further, aircraft is assumed to have symmetry inits mass distribution relative to its mid-vertical plane. There are, however, cases where the aircraft mass changes rapidly, most notably in aerial refueling operation.The mass change also results in changes in the inertia matrix. An aircraft may also …

On Space Program Planning: Quantifying The Effects Of Spacefaring Goals And Strategies On The Solution Space Of Feasible Programs, Mark Douglas Coley

Mechanical and Aerospace Engineering Dissertations - Archive

An organization's space program represents the coalescence of top-level goals and strategies with the specific, lower-level combinations of mission architectures, hardware, and technology. High costs and long lead times necessitate substantial planning and key decisions to be made years, possibly decades, in advance. Unfortunately, the methods and processes available for planning have historically been unable to provide decision-makers with objective, quantitative information from both the top and lower levels of the space program. Instead, decision-makers are forced to turn to top-level, qualitative assessments, disconnected from any of the fundamental, technical details, where inconsistent comparisons and secondary effects often become the …

Studying Effects Of Adhesive Layer On Electrical Signals Of Piezoelectric Transducer Bonded With Structure, Md Mazharul Islam

Mechanical and Aerospace Engineering Dissertations - Archive

Piezoelectric wafer active sensors (PWAS) are the most attractive transducers for guided-wave or ultrasound based structural health monitoring (SHM) because of their light weight and compact size. In order to excite guided waves in a structure, the PWASs are usually bonded on the surface of the structure by adhesive materials. The electrical signal applied to the surface bonded PWAS is converted to mechanical deformation of the PWAS which in turn is transferred to the structure through the adhesive layer. Thus, understanding the effects of the adhesive layer on the electrical response of the PWAS enables us to optimize the mechanical …

Nonlinear Model Predictive Control For Cooperative Control And Estimation, Pengkai Ru

Mechanical and Aerospace Engineering Dissertations - Archive

Recent advances in computational power have made it possible to do expensive online computations for control systems. It is becoming more realistic to perform computationally intensive optimization schemes online on systems that are not intrinsically stable and/or have very small time constants. Being one of the most important optimization based control approaches, model predictive control (MPC) has attracted a lot of interest from the research community due to its natural ability to incorporate constraints into its control formulation. Linear MPC has been well researched and its stability can be guaranteed in the majority of its application scenarios. However, one issue …

Characterization Of Vertically Split Distribution-Wet Cooling Media Used In Data Centers, Mullaivendhan Varadharasan

Mechanical and Aerospace Engineering Theses - Archive

Data Centers houses substantial number of information technology (IT) equipment like computer servers and storage modules associated with various electronic components which consume high volume of electricity. The IT equipment in data center housing keeps dissipates heat energy as it is constantly running day and night. To keep the data center environment under thermally control and to favor the reliability of electronic components, we need to adopt a cooling technique which aids the module level cooling, with due consideration of the size of the data center and its geographical location. One of the adopted cooling technique in data center thermal …

Composite Plate Optimization With Structural And Manufacturing Constraints, Deepak Polaki

Mechanical and Aerospace Engineering Theses - Archive

This is a design optimization study that focuses on the value of free size optimization technology on composite structures which incorporates realistic structural requirements and practical manufacturing limitations to achieve an iterative design with effective structural performance. To detail a study on such practical implementation, a sample structure is required. A rectangular composite laminate with a central hole cutout is considered for this study and is designed using finite elemental tools which includes compression, tension and shear loading conditions with load reactions at bolted joints and buckling stability. Free size optimization and size optimization are used in this study to …

Reliability Assessment Of Solder Joint Using Bga Package – Megtron 6 Versus Fr4 Printed Circuit Boards, Mugdha Anish Chaudhari

Mechanical and Aerospace Engineering Theses - Archive

When it comes to the mechanical and electrical seam of the Printed Circuit Board (PCB) and package, reliability of the board plays a major impact on PCB. As the frequency increases, losses in signals increase. This necessitates the use of new materials for such applications. Nelco 4000-13EPSI, Rogers 4350B, Panasonic Megtron 6 are few high-speed materials used. Studies have shown that Megtron 6 has the least dielectric losses so far, low transmission loss, high heat resistance and has low weight loss than the FR-4 boards. With an increasing demand for high performance, reliability and lower costs, the field of electronic …

Solder Joints Design Optimization Of Qfn Packages For Different Boards By Investigating Solder Joint Reliability, Rishikesh Vilas Tendulkar

Mechanical and Aerospace Engineering Theses - Archive

Quad Flat No-lead package (QFN) is one of the most cutting-edge technologies emerged in the market, exhibiting high performance and efficiency with unparalleled cost effectiveness. QFN, a leadless package, is an ideal choice for applications where size, weight thermal and electrical characteristics are critical, particularly in mobile and handheld devices. Applications like automotive, defense and high current circuits require the package to be mounted on thick printed circuit boards (PCB). The motivation of this work is to understand the effect of design variations of solder joints affecting reliability and optimize the solder package to improve reliability for application on different …

An Improved Method For Measurement Of Radial Thermal Conductivity Of Cylindrical Bodies, Salwa Shaik

Mechanical and Aerospace Engineering Theses - Archive

Li-ion cells are ubiquitously found in day to day electronic devices due to their high power density storage capacity. These batteries are known to exhibit sharp reduction in performance at high temperature. Due to this, several attempts have been made in the past to measure thermal properties of the Li-ion cell. This work improves upon past measurements by showing that heat loss during measurements is non-negligible, and by developing an analytical model to account for such heat loss. Experimental measurements carried out on multiple materials demonstrate non-negligible heat loss. When accounted analytically, these data result in thermal conductivity values that …

Electro-Pneumatic Shifting And Servo Control Of A Clutch For A Fsae Racecar, Rahul Janardhan Chalmela

Mechanical and Aerospace Engineering Theses - Archive

FSAE is an international student design competition held by SAE International where students design, build and compete in static events like cost, design and dynamic events ranging from acceleration, autocross to endurance. UTA Racing has been a part of FSAE since 1982 and have been using a mechanical design for their shifter and clutch since then. This year for the 2017 design competition an electro-pneumatic system is developed to replace the mechanical system. This system consists of pneumatic cylinders controlling a sequential shifter and a servo clutch. The cylinders are controlled using direction control valves, these receive their signals from …

Rack Level Study Of Hybrid Cooled Servers Using Warm Water Cooling With Variable Pumping For Centralized Coolant System, Chinmay Sanjay Kshirsagar

Mechanical and Aerospace Engineering Theses - Archive

As the worldwide demand for the data centers grows, so does the size and load placed on data centers which leads to the applied constraints on power and space available to the operator. Cooling power consumption is a major contributor of the total energy consumption of the system. In the process of optimization of cooling energy consumption per performance unit, liquid cooling technology has emerged as one of the most viable solutions. In this rack level study, 2OU (Open U) hybrid cooled web servers are tested for an evaluation of warm water cooling in centralized coolant system. Effects of higher …

Load Carrying Capacity Management Of Compound Anisotropic Composite Rings Under External Pressure, Salman Bakhrayba

Mechanical and Aerospace Engineering Theses - Archive

Composites have much higher strength than conventional materials such as steel. This makes it attractive to replace heavy loaded structural elements, made traditionally from steel, by elements made from composites. However, it is not a trivial task for statically indeterminate structures due to anisotropy of elastic and strength properties of composites. Present investigation is done for a ring subjected to external load. Such rings are used as bulkheads in many applications. Dependence of ultimate external pressure on thickness of the ring is nonlinear one. It is related to non-uniformity of distribution of circumferential stresses, with anisotropy of material, with set …

Comparative Study Of Viscoelastic Modeling And Linear Modeling For Wafer Level Chip Scale Package Under Drop Impact, Navya Sri Reddy Kasi Reddy

Mechanical and Aerospace Engineering Theses - Archive

Wafer level chip scale packages are one the preferred choice in the electronic industry to meet the need of new miniaturization of the recent devices. It has high efficiency in packaging and has low cost. On the other hand, the drop impact failure is one of the growing risk in day to day use of the portable devices. Therefore, to ensure product quality and to integrate more complicated functionality in these devices comprehensive reliability tests need to be performed before delivering the product. Accelerated thermal cycling, drop testing and power cycling are some accepted test methods used to access board …

A Comparative Study Of Wooden And Composite Crossarm Of An Electric Utility Pole, Amith Venkatesh

Mechanical and Aerospace Engineering Theses - Archive

Currently, most of the crossarms existing in the nation are made of wood. However, wood has a set of negative features like shorter life span due to environmental cracking, damages by insects and birds. Secondly, an insufficient strength and stiffness which is compensated either by increasing the cross-section or by reducing the span between two poles. Also, it’s reduced insulating property in case of high humidity of air which can be accounted to its hygroscopic behavior. Replacement of wooden crossarms by composite crossarms is a known solution to many problems. However, the existing projects are far from optimal. Present investigation …

Thermal Characterization Of An Isolated Hybrid Cooled Server With Pump And Fan Failure Scenarios, Uschas Chowdhury

Mechanical and Aerospace Engineering Theses - Archive

Modern day data centers are operated at high power for increased power density, maintenance, and cooling which covers almost 2 percent (70 billion kilowatt-hours) of the total energy consumption in the US. IT components and cooling system occupy the major portion of this energy consumption. Although data centers are designed to perform efficiently, cooling the high-density components is still a challenge. So, alternative methods to improve the cooling efficiency has become the drive to reduce the cooling cost. As liquid cooling is more efficient for high specific heat capacity, density, and thermal conductivity, hybrid cooling can offer the advantage of …

Comparison Of Mechanical Behaviour Of Metallic And Composite Front Door Of A Standard Automobile Car By Fea, Aniket Chandu Thosar

Mechanical and Aerospace Engineering Theses - Archive

With the advent of technology, materials have advanced many folds; one such technical revelation has been Fiber-reinforced Composite Materials. Composite materials have two major advantages, among many others: improved strength and stiffness, especially compared to other materials on a unit weight basis and low density with ease of manufacturing. These advantages have led to new aeronautical, automobile and marine designs that are radical departures from past efforts based on conventional materials. This paper focusses on a comparative study between Aluminum Alloys, Manganese alloys, structural steel, Composite materials and investigates the static and dynamic behaviors for a composite front door of …

Experimental And Computational Investigation Of The Need For An Acclimation For Operating It Equipment, Ramesh Prasanna Manohar

Mechanical and Aerospace Engineering Theses - Archive

Acclimation of IT equipment is not only for newly commissioned equipment but are also for the equipment that is already in use. In conventional Data Center, IT Equipment are cooled by traditional cooling methods, but due to increasing serious energy crisis, Data Centers are Free cooled because of the reduced power consumption. Free Cooling a Data Center is, when the outside air conditions are appropriate, they are drawn into the Data Center to cool the Operating IT Equipment. Data Centers uses dampers to control the type of cooling to be used. Due to a rapid change in the temperature and …

Numerical Study Of Marangoni Convection And Mass Transport In Microdroplets, Viraj Parag Sabane

Mechanical and Aerospace Engineering Theses - Archive

Marangoni convection is a flow resulting from a surface tension gradient at air/liquid interface caused by temperature gradient, concentration of surfactant or applied electric field. Marangoni convection when caused by temperature gradient is also known as thermo-capillary effect. A microgravity condition presents an ideal case to study this phenomenon, since interfacial forces are dominant over body forces. Hence Marangoni convection inside the micro-droplet was studied both numerically and experimentally. The potential application at micro-scale includes particle separation, chaotic mixing inside the droplet and possible enhancement in liquid liquid extraction. To explore these application, firstly flow field inside a droplet was …

Design And Analysis Of A 10” Carbon Fiber Wheel For A Formula Sae Racecar, Pratik Ganesh G Bhagwat

Mechanical and Aerospace Engineering Theses - Archive

Formula SAE is an engineering design competition for students where the goal is to design, build, and compete a Formula-style single seater race vehicle. With a legacy dating back to 1982, UTA Racing has been one of the most competitive teams. In this project, a carbon fiber 10” wheel is designed for the first time, achieving reduced unsprung weight and lower rotational inertia, both of which are key performance characteristics in vehicle dynamics. The design follows Tire and Rim Association guidelines to ensure dimensional compatibility and ease of assembly and is analyzed for 2G cornering with 3G bump. The simulations …