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Articles 1 - 30 of 40
Full-Text Articles in Engineering
Rotor Position And Vibration Control For Aerospace Flywheel Energy Storage Devices And Other Vibration Based Devices, B. X. S. Alexander
Rotor Position And Vibration Control For Aerospace Flywheel Energy Storage Devices And Other Vibration Based Devices, B. X. S. Alexander
ETD Archive
Flywheel energy storage has distinct advantages over conventional energy storage methods such as electrochemical batteries. Because the energy density of a flywheel rotor increases quadratically with its speed, the foremost goal in flywheel design is to achieve sustainable high speeds of the rotor. Many issues exist with the flywheel rotor operation at high and varying speeds. A prominent problem is synchronous rotor vibration, which can drastically limit the sustainable rotor speed. In a set of projects, the novel Active Disturbance Rejection Control (ADRC) is applied to various problems of flywheel rotor operation. These applications include rotor levitation, steady state rotation …
Characterization Of Changes In Hyaluronan Following Epidermal Barrier Injury In An Organotypic Model, Gati Ajani
Characterization Of Changes In Hyaluronan Following Epidermal Barrier Injury In An Organotypic Model, Gati Ajani
ETD Archive
The stratum corneum, the outermost layer of the epidermis of skin, provides a functional permeability barrier that is essential for our survival and must be rapidly repaired after injury. Of interest to us, a ubiquitous matrix molecule called hyaluronan (HA) has come to the forefront in wound healing research because it is induced after epidermal injury and may be crucial for barrier repair. This thesis examines the role of HA during recovery from the most fundamental form of skin injury, i.e. selective damage to the stratum corneum. The overall question is whether this form of stratum corneum injury can lead …
Novel Antifreeze Protein Constructs For Improved Activity, Ozge Can
Novel Antifreeze Protein Constructs For Improved Activity, Ozge Can
ETD Archive
Many organisms are exposed to subzero temperatures in nature and can survive these temperatures by the effect of antifreeze proteins (AFPs), which inhibit ice crystal growth and change the morphology of ice crystals. Although the effects of these proteins, such as recrystallization inhibition, ice growth inhibition, and crystal habit changes, are known, a conclusive description of the protein-ice crystal interaction including interaction energy, surface coverage, and lifetime of adsorbate has been elusive. In this study, different antifreeze protein constructs are designed and expressed such that they can be conjugated to polymers to increase the thermal hysteresis activity especially at low …
Fabrication Of Nanostructured Metals And Their Hydrogen Storage Properties, Asli Ertan
Fabrication Of Nanostructured Metals And Their Hydrogen Storage Properties, Asli Ertan
ETD Archive
Searching for new energy sources is highly desirable for the next generations when rapidly changing factors are considered such as population, increasing pollution and exhaustion of fossil fuels. Hence, there is a need for clean, safe and efficient energy carriers or forms of energy that can be transported to the end user. One of these energy carriers is electricity which has been used widely and can be produced from various sources. However, its production from fossil fuels contributes to pollution. On the other hand hydrogen, due to its abundance, light weight, low mass density, high energy density and non-polluting nature …
A Hybrid Reconfigurable Solar And Wind Energy System, Sagar A. Gadkari
A Hybrid Reconfigurable Solar And Wind Energy System, Sagar A. Gadkari
ETD Archive
We study the feasibility of a novel hybrid solar-wind hybrid system that shares most of its infrastructure and components. During periods of clear sunny days the system will generate electricity from the sun using a parabolic concentrator. The concentrator is formed by individual mirror elements and focuses the light onto high intensity vertical multi-junction (VMJ) cells. During periods of high wind speeds and at night, the same concentrator setup will be reconfigured to channel the wind into a wind turbine which will be used to harness wind energy. In this study we report on the feasibility of this type of …
The Development Of An In Vivo Spinal Fusion Monitor Using Microelectromechanical (Mems) Technology To Create Implantable Microsensors, Lisa Anne Ferrara
The Development Of An In Vivo Spinal Fusion Monitor Using Microelectromechanical (Mems) Technology To Create Implantable Microsensors, Lisa Anne Ferrara
ETD Archive
Surgical fusion of the spine is a conventional approach, and often last alternative, to the correction of a degenerative painful spinal segment. The procedure involves the surgical removal of the intervertebral disc at the problematic site, and the placement of a bone graft that is commonly harvested from the patients iliac crest and placed within the discectomized space. The surrounding bone is expected to incorporate and remodel into the bone graft to eventually provide an immobilized site. Spinal instrumentation often accompanies the bone graft to provide further immobility to the targeted site, thus augmenting the fusion process. However, the status …
Effective Area And Effective Volume Calculations For Ceramic Test Specimens, Rahul Jain
Effective Area And Effective Volume Calculations For Ceramic Test Specimens, Rahul Jain
ETD Archive
Calculation of effective volume and/or effective area is a key step in estimating reliability of ceramic component life cycle. Most common tests performed to assess the strength and reliability of components made from ceramics are bend bar specimens tested in three-point and four-point flexure, C-ring and O-ring specimen under diametral compressive or tensile loads and biaxial ring-on-ring specimens. ASTM closed form solutions for the effective volume and area exists for these specimen geometries which are based on classical theories with underlying assumptions. In general the closed form expressions are valid for limited specimen geometry bounds. An alternative numerical approach has …
Relationship Between Arch Height And Midfoot Joint Pressures During Gait, Dong Gil Lee
Relationship Between Arch Height And Midfoot Joint Pressures During Gait, Dong Gil Lee
ETD Archive
A foot arch is a multi-segmented curved structure which acts as a spring during locomotion. It is well known that ligaments are important components contributing to this spring-like property of the arch. In addition, intrinsic and extrinsic foot muscles contribute to arch support. According to the windlass foot model, arch height and midfoot joint orientation change during gait. However, it is not known whether altered joint configurations result in increased joint stress during gait. If so, it is possible for there to be a "vicious cycle" in which joint stress increases as the arch height diminishes, which may then lead …
Greenometer-7: A Tool To Assess The Sustainability Of A Building's Life Cylce At The Conceptual Design Phase, Muhammad Musa Mer'eb
Greenometer-7: A Tool To Assess The Sustainability Of A Building's Life Cylce At The Conceptual Design Phase, Muhammad Musa Mer'eb
ETD Archive
This study presents a tool that has been developed to measure and subsequently improve the sustainability performance of a building over its entire life-cycle while still at the conceptual design stage. This forecasting tool is called GREENOMETER-7. GREENOMETER-7 is a LCA tool and it evaluates the projected building at two levels: micro- and macro-assessment. The micro-assessment level provides in-depth analysis of the building products, components, and operations however, the macro-assessment level measures the sustainability performance of the building as a whole and covers areas that are not applicable at the product or component level. Both levels consist of categories and …
Mems (Micro-Electro-Mechanical-Systems) Based Microfluidic Platforms For Magnetic Cell Separation, Pulak Nath
Mems (Micro-Electro-Mechanical-Systems) Based Microfluidic Platforms For Magnetic Cell Separation, Pulak Nath
ETD Archive
Microfluidic platforms for magnetic cell separation were developed and investigated for isolation of magnetic particles and magnetically tagged cells from a fluidic sample. Two types of magnetic separation platforms were considered: an Isodynamic Open Gradient Magnetic Sorter (OGMS) and a multistage bio-ferrograph. Miniaturized magnets were designed using magnetostatic simulation software, microfluidic channels were fabricated using microfabrication technology and magnetic separation was investigated using video microscopy and digital image processing. The isodynamic OGMS consisted of an external magnetic circuit and a microfabricated channel (biochip) with embedded magnetic elements. The biochip is placed inside the magnetic field of the external circuit to …
A Novel Cardiac Pacing Paradigm For Atrial Fibrillation And Heart Failure Patients, George Emanuel Yanulis
A Novel Cardiac Pacing Paradigm For Atrial Fibrillation And Heart Failure Patients, George Emanuel Yanulis
ETD Archive
It has been estimated that 4.6 million persons have heart failure, and 400,000 to 700,000 new cases develop each year and the U.S. Hospital discharges for HF rose from 399,000 in 1979 to 1,099,000 in 2004 according to the National Hospital Discharge Survey. Atrial fibrillation is the most common sustained cardiac arrhythmia in the United States. Recent studies have demonstrated that ventricular rate control is a viable treatment strategy for patients in atrial fibrillation. In a number of cases, despite the electrical resynchronization of the ventricles using biventricular pacing (cardiac resynchronization therapy), heart failure patients in sinus rhythm do not …
Bio-Signal Analysis In Fatigue And Cancer Related Fatigue;Weakening Of Corticomuscular Functional Coupling, Qi Yang
ETD Archive
Fatigue is a common experience that reduces productivity and increases chance of injury, and has been reported as one of most common symptoms with greatest impact on quality-of-life parameters in cancer patients. Neural mechanisms behind fatigue and cancer related fatigue (CRF) are not well known. Recent research has shown dissociation between changes in brain and muscle signals during voluntary muscle fatigue, which may suggest weakening of functional corticomuscular coupling (fCMC). However, this weakening of brain-muscle coupling has never been directly evaluated. More important information could be gained if fCMC is directly detected during fatigue because a voluntary muscle contraction depends …
Biocompatibility Of Osteoblast Cells On Titanium Implants, Dilip Ayyala Somayajula
Biocompatibility Of Osteoblast Cells On Titanium Implants, Dilip Ayyala Somayajula
ETD Archive
Adhesion and proliferation of UMR 106-01 osteoblast cells were studied on various surface modified titanium materials such as polished, sandblasted, anodized and alkaline treated. Anodization of polished surface in Hydrofluoric acid developed nano-tubes, while NaOH treatment produced spongy microporous morphology. Test samples were coated with non-adhesive protein bovine serum albumin and compared with fibronectin coated specimens. The adhesion study lasted for 4 hrs, where osteoblast cells were cultured in serum free medium. Polished titanium, anodized titanium and NaOH titanium have shown similar percentages of cell adherence. The proliferation study lasted for 48 hrs, where cells were initially allowed to adhere …
Broader Use Of Steel Slag Aggregates In Concrete, Jigar P. Patel
Broader Use Of Steel Slag Aggregates In Concrete, Jigar P. Patel
ETD Archive
Steel slag is an industrial byproduct obtained from the steel manufacturing industry. It is produced in large quantities during the steel-making operations which utilize Electric Arc Furnaces (EAF). Steel slag can also be produced by smelting iron ore in the Basic Oxygen Furnace (BOF). Steel slag can be used in the construction industry as aggregates in concrete by replacing natural aggregates. Natural aggregates are becoming increasingly scarce and their production and shipment is becoming more difficult. Steel slag is currently used as aggregate in hot mix asphalt surface applications, but there is a need for some additional work to determine …
Experimental Test And Cost Analysis Of Residential Solar Water Heaters, Sai Mahesh Dharanikota
Experimental Test And Cost Analysis Of Residential Solar Water Heaters, Sai Mahesh Dharanikota
ETD Archive
Non renewable energy sources have been diminishing in the recent times.Renewable energy is abundant in nature, but the use of it is very low.Lowering the energy consumption and using renewable energy, thereby decreasing the use of fossil fuels and nuclear energy would have a positive impact on our environment. The use of solar energy as an alternate resource is discussed in this research. The solar water heater is tested for its recovery rates, under normal solar radiation in static testing. The effect of solar radiation in increasing the temperature of water is studied and discussed. The solar water heater is …
Effect Of Adding A Regenerator To Kornhauser's Mit "Two-Space" Test Rig, Praveen Gidugu
Effect Of Adding A Regenerator To Kornhauser's Mit "Two-Space" Test Rig, Praveen Gidugu
ETD Archive
A 3-space solution domain (gas spring + heat exchanger + regenerator) is adapted from the 2-space solution domain (gas spring + heat exchanger) in Kornhauser MIT test rig [25] by modifying the heat exchanger space to include a porous regenerator system. A thermal non-equilibrium porous-media model is employed for the regenerator. Extensive numerical simulations of the fluid flow and heat transfer phenomena under conditions of oscillating pressure and oscillating fluid flow inside the 3-space solution domain were performed using 1-D Sage and 2-D Fluent numerical codes. 3-space results of temperature, pressure and surface heat transfer variations, pressure-volume diagrams, energy conservation …
Radiation View Factors Between A Disk And The Interior Of A Class Of Axisymmetric Bodies Including Converging Diverging Rocket Nozzles, Mark Richard Murad
Radiation View Factors Between A Disk And The Interior Of A Class Of Axisymmetric Bodies Including Converging Diverging Rocket Nozzles, Mark Richard Murad
ETD Archive
A general symbolic exact analytic solution is developed for the radiation view factors including shadowing by the throat between a divergence thin gas disk between the combustion chamber and the beginning of the rocket nozzle radiating energy to the interior downstream of the nozzle contour for a class of coaxial axisymmetric converging diverging rocket nozzles. The radiation view factors presented in this thesis for the projection which are blocked or shadowed through the throat radiating downstream to the contour have never been presented before in the literature. It was found that the curvature of the function of the contour of …
Application Of Reverse Engineering And Rapid Prototyping To Casting, Venkat Deepak Kolar
Application Of Reverse Engineering And Rapid Prototyping To Casting, Venkat Deepak Kolar
ETD Archive
The automotive industry has an increasing need for the re manufacturing of spare parts through reverse engineering. In this thesis we will review the techniques used in Fused Deposition Modeling system for the reverse engineering of vintage automotive parts. The objective of the project is to be able to generate part-to-CAD and CAD-to-part reconstruction of the original part for future usage. These newly created 3D models will be added to the 3D Part Database. The integration of reverse engineering and rapid prototyping is being used for getting product to the market quickly by resolving a long-standing conflict between design and …
Experimental Testing And Performance Analysis Of "Room Air Cleaners", Pavan Kumar Mudiya
Experimental Testing And Performance Analysis Of "Room Air Cleaners", Pavan Kumar Mudiya
ETD Archive
HMI industries are the manufacture of the air cleaners and vacuum cleaners, in which a solution is adapted for the current model of the volute to the new design of the volute in order to calculate the "Clean Air Delivery rate" and qualify for the "Energy Star requirements". For the above model to be employed as a Energy Star certificate, a test rig was made in which "air velocity" and "flow rate" was calculated for the three different air cleaners in two cases i.e. (i) three different air cleaners with different filters and different rpm's (ii) three different air cleaners …
Probabilistic Finite Element Heat Transfer And Structural Analysis Of A Cone-Cylinder Pressure Vessel, Omar Haddad
Probabilistic Finite Element Heat Transfer And Structural Analysis Of A Cone-Cylinder Pressure Vessel, Omar Haddad
ETD Archive
Stress analysis of a cone-cylinder pressure vessel was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall Von Mises stresses due to the structural and thermodynamic random variables. These results can be used to quickly identify the most critical design variables in order to optimize the design and make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in structural and heat transfer analysis and to the identification of both the most …
Mathematical Analysis Of A Geothermal System, Ivan P. Erceg
Mathematical Analysis Of A Geothermal System, Ivan P. Erceg
ETD Archive
The issue being examined is to design a more economical and efficient therefore superior geothermal system than currently in use in industry. Current geothermal systems are designed and built 300 feet into the ground. After researching ground temperature gradients for Ohio we found out that below 10 feet of depth, the temperature varies by 1 degree Fahrenheit per 100 feet depth. Our goal is to utilize the heat as close to the surface as possible and greatly reduce the need to dig so deeply into the ground. The procedure used to go about designing a superior geothermal system is to …
Convolutional Coded Generalized Direct Sequence Spread Spectrum, Madan Venn
Convolutional Coded Generalized Direct Sequence Spread Spectrum, Madan Venn
ETD Archive
In this thesis we investigate the worst-case performance of coded ordinary and coded generalized direct sequence spread spectrum (DSSS) systems in a communication channel corrupted by an unknown and arbitrary interfering signal of bounded power. We consider convolutional codes with Viterbi decoding in order to compare the performance of coded ordinary and coded generalized DSSS systems. For the generalized DSSS system, we use a pulse stream of +1,-1 and 0 as the spreading sequence, which is different from ordinary DSSS system which uses the typical sequence with pulse values of +1 and -1. A C program for performing Monte-Carlo simulations …
Comparison Of Methods For Developing Estimated Parameter̄X Control Charts Propsed By Nedumaran & Pignatiello, Albers & Kallenberg And Tsai Et Al., Ozlem Temiz
ETD Archive
The subject of this thesis is the comparison of the development method used to determine the value of Xbar control chart limits when the underlying process parameters are unknown and must be estimated from data obtained from a Phase I historical samples. I propose in the research for this thesis to compare these three proposed methods in detail comparing their performance by developing empirical probability of signal distributions for both in-control and out-of-control situations. Generation of these distributions will be accomplished through discrete simulation. The final result will consist of recommendations concerning the best of the methods to use in …
Road Surface Condition Detection And Identification And Vehicle Anti-Skid Control, Maosheng Ye
Road Surface Condition Detection And Identification And Vehicle Anti-Skid Control, Maosheng Ye
ETD Archive
Road surface condition is greatly dependent on the surface's friction coefficient. The abrupt change of the coefficient results in variation of wheel slip which likely leads to vehicle instability. Vehicle steering model and the dynamic equations for four-wheel drive vehicle is developed. A new observer, called Extended State Observer (ESO) is used to estimate the longitudinal velocity, lateral velocity and yaw rate, and more importantly an additional quantity known as system dynamics. A trained neural network was employed to help determine the friction coefficient. Fuzzy logic was employed to quickly detect the change of road surface condition and further classify …
High Intensity Laser Power Beaming For Wireless Power Transmission, Daniel Edward Raible
High Intensity Laser Power Beaming For Wireless Power Transmission, Daniel Edward Raible
ETD Archive
This paper describes work supporting the development of a high intensity laser power beaming (HILPB) system for the purpose of wireless power transmission. The main contribution of this research is utilizing high intensity lasers to illuminate vertical multi-junction (VMJ) solar cells developed by NASA-GRC. Several HILPB receivers are designed, constructed and evaluated with various lasers to assess the performance of the VMJ cells and the receiver under a variety of conditions. Several matters such as parallel cell back-feeding, optimal receiver geometry, laser wavelength, non-uniform illumination and thermal effects at high intensities are investigated. Substantial power densities are achieved, and suggestions …
A Kinematics Based Tolerance Analysis Of Mechanisms, Shahrbanoo Biabnavi Farkhondeh
A Kinematics Based Tolerance Analysis Of Mechanisms, Shahrbanoo Biabnavi Farkhondeh
ETD Archive
A kinematic based tolerance analysis of mechanisms is presented in this thesis. It is shown that standard kinematic analysis can be used for obtaining closed-form explicit formulations for tolerance analysis of mechanisms. It is proposed that the manufacturing tolerances are accounted for by incorporating fictitious sliding members in the rigid links, thereby allowing them to either "grow" or "shrink" along the lines of their pin connections. The virtual expansions or contractions of these fictitious sliders are captured in the kinematic equations by taking the differentials of the magnitudes of the vectors that define the length of rigid links having dimensional …
Modeling Of Transient Thrust Of A Two Phase Propellant Tank, Karthik Mellechervu
Modeling Of Transient Thrust Of A Two Phase Propellant Tank, Karthik Mellechervu
ETD Archive
This thesis develops a model to predict various time-varying quantities associated with the evacuation of a pressurized container through a nozzle. The container is part of a satellite propulsion prototype used to study attitude control. Variables of interest include the thrust and mass of fluid in the tank as functions of time. A mathematical model based on transient expressions for mass and energy conservation is derived for a two-phase system representative of the conditions of the fluid inside the tank
Multiplexed Control Of Smart Structure Using Piezoelectric Actuators, Kumar S. Nale
Multiplexed Control Of Smart Structure Using Piezoelectric Actuators, Kumar S. Nale
ETD Archive
Active control of smart structures containing a large number of actuators and sensors presents a tradeoff between increased system performance and the cost and bulk of the required hardware and computational resources. A technique called multiplexed control offers advantages when software and hardware resources are scarce and performance specifications call for a large number of actuators and sensors. In structural control applications, in particular those using smart materials, it is often desirable to increase the number of actuators to enhance controllability.The focus of this research is to demonstrate real-time multiplexing on the hardware side of the actively controlled structure. Multiplexing …
Effect Of Axial Oscillation On Performance Of Hydrodynamic Journal Bearings, Thomas Wirsing
Effect Of Axial Oscillation On Performance Of Hydrodynamic Journal Bearings, Thomas Wirsing
ETD Archive
The hydrodynamic coefficients of a journal bearing set with the bearing subjected to axial oscillation are determined in this work. The Navier-Stokes equations were used to account for the axial component of the relative motion between the journal and the bearing. Numerical solution of the Navier-Stokes equations yielded the pressure distribution within the cavity of the bearing. This pressure distribution was then integrated over the surface of the bearing to obtain the two orthogonal force components. The derivatives of these force components were then taken with respect to the displacement and velocity of the journal that are co-linear with these …
Motion Control Of An Open Container With Slosh Constraints, Kedar B. Karnik
Motion Control Of An Open Container With Slosh Constraints, Kedar B. Karnik
ETD Archive
General motion control of conveyor belts does not present difficulties. When the conveyor belt carries open containers filled with liquid, significant analysis needs to be carried out to design controllers. The objective of this thesis was to design a control system which will allow an open container filled with liquid to be transferred between two stations as fast as possible and without excessive slosh causing the liquid to spill out of the container. This control problem has applications to industrial processing facilities, where open containers are carried by a conveyor belt. The speed at which the open container can be …