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Full-Text Articles in Engineering
Mechanistic Undrestanding Of Amorphization In Iron-Based Soft Magnetic Materials, Taban Larimian
Mechanistic Undrestanding Of Amorphization In Iron-Based Soft Magnetic Materials, Taban Larimian
ETD Archive
Iron-based magnetic alloys possess very good magnetic and mechanical properties. Among these alloys Fe-Si-B-based alloys show outstanding saturation magnetization and coercivity which makes them great candidates for many industrial applications. Addition of certain elements to the Fe-Si-B base is proven to improve the homogeneity and fineness of microstructure as well as enhance the magnetic behavior of these alloys. In this research work, we have studied the effect of adding copper and niobium to the Fe-Si-B base alloy. Previous studies have shown that magnetic alloys show better magnetic properties when their microstructure consists of nanocrystals embedded in an amorphous matrix. In …
Viability And Accessibility Of Urban Heat Island And Lake Microclimate Data Over Current Tmy Weather Data For Accurate Energy Demand Predictions., Irena A. Weclawiak
Viability And Accessibility Of Urban Heat Island And Lake Microclimate Data Over Current Tmy Weather Data For Accurate Energy Demand Predictions., Irena A. Weclawiak
ETD Archive
Building Energy Simulations (BES) are necessary for designing energy-efficient systems. Open-source simulation software developed by the Department of Energy (DOE), EnergyPlus (EP) provides Typical Meteorological Year (TMY) weather data that consists of a 15-year average. Two major concerns about this data are the inability to detect extreme conditions and limited data locations. There is a greater number of Microclimate (MC) stations that can be used for simulations, but it involves time-consuming data preparation to match the EP format. This study investigated the effects of Urban Heat Island (UHI) and the MC of Lake Erie. A comparison of the MC data …
An Evaluation And Economic Analysis Of A Water Main Geothermal System In A Residential Space, Brian L. Kohut
An Evaluation And Economic Analysis Of A Water Main Geothermal System In A Residential Space, Brian L. Kohut
ETD Archive
Iron-based magnetic alloys possess very good magnetic and mechanical properties. Among these alloys Fe-Si-B-based alloys show outstanding saturation magnetization and coercivity which makes them great candidates for many industrial applications. Addition of certain elements to the Fe-Si-B base is proven to improve the homogeneity and fineness of microstructure as well as enhance the magnetic behavior of these alloys. In this research work, we have studied the effect of adding copper and niobium to the Fe-Si-B base alloy. Previous studies have shown that magnetic alloys show better magnetic properties when their microstructure consists of nanocrystals embedded in an amorphous matrix. In …
Design, Control, And Optimization Of Robots With Advanced Energy Regenerative Drive Systems, Poya Khalaf
Design, Control, And Optimization Of Robots With Advanced Energy Regenerative Drive Systems, Poya Khalaf
ETD Archive
We investigate the control and optimization of robots with ultracapacitor based regenerative drive systems. A subset of the robot joints are conventional, in the sense that external power is used for actuation. Other joints are energetically self-contained passive systems that use ultracapacitors for energy storage. An electrical interconnection known as the star configuration is considered for the regenerative drives that allows for direct electric energy redistribution among joints, and enables higher energy utilization efficiencies. A semi-active virtual control strategy is used to achieve control objectives. We find closed-form expressions for the optimal robot and actuator parameters (link lengths, gear ratios, …
Robust Impedance Control Of A Four Degree Of Freedom Exercise Robot, Santino Joseph Bianco
Robust Impedance Control Of A Four Degree Of Freedom Exercise Robot, Santino Joseph Bianco
ETD Archive
The CSU 4OptimX exercise robot provides a platform for future research into advanced exercise and rehabilitation. The robot and its control system will autonomously modify reference trajectories and impedances on the basis of an optimization criterion and physiological feedback. To achieve this goal, a robust impedance control system with trajectory tracking must be implemented as the foundational control scheme. Two control laws will be compared, sliding mode and H-infinity control. The above robust control laws are combined with underlying impedance control laws to overcome uncertain plant model parameters and disturbance anomalies affecting the input signal. The sliding mode control law …
Neuromuscular Reflex Control For Prostheses And Exoskeletons, Sandra K. Hnat
Neuromuscular Reflex Control For Prostheses And Exoskeletons, Sandra K. Hnat
ETD Archive
Recent powered lower-limb prosthetic and orthotic (P/O) devices aim to restore legged mobility for persons with an amputation or spinal cord injury. Though various control strategies have been proposed for these devices, specifically finite-state impedance controllers, natural gait mechanics are not usually achieved. The goal of this project was to invent a biologically-inspired controller for powered P/O devices. We hypothesize that a more muscle-like actuation system, including spinal reflexes and vestibular feedback, can achieve able-bodied walking and also respond to outside perturbations. The outputs of the Virtual Muscle Reflex (VMR) controller are joint torque commands, sent to the electric motors …
Non-Intrusive Optical Measurement Of Electron Temperature In Near Field Plume Of Hall Thruster, Peter J. Urban
Non-Intrusive Optical Measurement Of Electron Temperature In Near Field Plume Of Hall Thruster, Peter J. Urban
ETD Archive
Currently there is a large interest in the use of more efficient means of propulsion in long term missions due to the costs and difficulties associated with placing and maintaining the needed fuel for conventional chemical systems in orbit. Mass reduction of upper stages will return large returns due to the great reduction in required lower stage fuel. Due to these factors, alternatives are undergoing active research, though this paper is concerned with the area of electrical propulsion. Electric propulsion is broadly defined as propulsion where the energization of the exhaust occurs via application of electromagnetic fields as opposed to …
A Transformative Process Control Solution, Simone Castanho Nobrega De Almedia Soares
A Transformative Process Control Solution, Simone Castanho Nobrega De Almedia Soares
ETD Archive
Knowing that a technology invented almost hundred years ago (PID controller) is still dominating industrial process control, a historical review was done to understand how the control field evolved. Model dependency and high level of mathematics appear as the main reasons that prevent other technologies from penetrating the engineering practice. A relatively novel methodology introduced by J. Han in 1998 called Active Disturbance Rejection Control (ADRC) came with characteristics that matches process control needs and restrictions on model dependency. This study will present a transformative solution for process control based on that. The control algorithm is designed and discretized for …
Real-Time Assessment And Visual Feedback For Patient Rehabilitation Using Inertial Sensors, Deepa Adinarayanan
Real-Time Assessment And Visual Feedback For Patient Rehabilitation Using Inertial Sensors, Deepa Adinarayanan
ETD Archive
Rehabilitation exercises needs have been continuously increasing and have been projected to increase in future as well based on its demand for aging population, recovering from surgery, injury and illness and the living and working lifestyle of the people. This research aims to tackle one of the most critical issues faced by the exercise administers-Adherence or Non-Adherence to Home Exercise problems especially has been a significant issue resulting in extensive research on the psychological analysis of people involved. In this research, a solution is provided to increase the adherence of such programs through an automated real-time assessment with constant visual …
Influence Of Natural Convection During Dendritic Array Growth Of Metal Alloys (Gradient Freeze Directional Solidification), Suyog N. Mahajan
Influence Of Natural Convection During Dendritic Array Growth Of Metal Alloys (Gradient Freeze Directional Solidification), Suyog N. Mahajan
ETD Archive
Purpose of this study was to examine the microstructural evolution of primary dendrites during Gradient Freeze Directional Solidification process in cylindrical Pb-5.8% Sb alloy samples to generate the ground- based research data to support a future microgravity experiment on the Space Station in a convection free environment. Pb-5.8Sb was selected for this study because of its ease of processing and availability of physical property data which will be required for predicting the dendrite morphology parameters, such as, primary dendrite spacing and dendrite trunk diameter. This alloy is also susceptible to thermosolutal convection caused by density inversion of the met in …
Effect Of Convection Associated With Cross-Section Change During Directional Solidification Of Binary Alloys On Dendritic Array Morphology And Macrosegregation, Masoud Ghods
ETD Archive
This dissertation explores the role of different types of convection on macrosegregation and on dendritic array morphology of two aluminum alloys directionally solidified through cylindrical graphite molds having both cross-section decrease and increase. Al- 19 wt. % Cu and Al-7 wt. % Si alloys were directionally solidified at two growth speed of 10 and 29.1 µm s-1 and examined for longitudinal and radial macrosegregation, and for primary dendrite spacing and dendrite trunk diameter.
Directional solidification of these alloys through constant cross-section showed clustering of primary dendrites and parabolic-shaped radial macrosegregation profile, indicative of “steepling convection” in the mushy-zone. The degree …
Design And Control Of A Powered Rowing Machine With Programmable Impedance, Jose Humberto De La Casas Zolezzi
Design And Control Of A Powered Rowing Machine With Programmable Impedance, Jose Humberto De La Casas Zolezzi
ETD Archive
Due to the rise of obesity, diabetes and cardiovascular disease, research in human performance and physical activity has received increased attention. Rowing machines are used for performance improvements through concentric exercises, however a combination of concentric and eccentric actions is known to improve the effectiveness of training. In this work, a conventional rowing machine was modified to include an electric motor and a robust impedance control system, enabling programmable impedance with concentric and eccentric capabilities. Eccentric exercises are known to contribute significantly to the efficacy of training and to diminish the detrimental effects of humans operating in microgravity for long …
Investigation Of Extremum Seeking Control For Adaptive Exercise Machines, Brahm T. Powell
Investigation Of Extremum Seeking Control For Adaptive Exercise Machines, Brahm T. Powell
ETD Archive
Many muscle rehabilitation regimens are non-adaptive and recommended subjectively by physicians. While there are advantages to having the feedback of a qualified physician, utilizing real-time muscle performance feedback could be beneficial. An extremum seeking control design is proposed to fulfill the need for an automated, load-varying exercise machine that can optimize muscle performance.
Several steps are outlined to contribute to the realization of this goal. First, the extremum seeking control scheme is discussed. Second, the Hill muscle model will be described. Theoretical muscle effort extrema will be derived for selected optimization cases, namely maximizing average squared power by varying load …
Electrochemical And Electroflotation Processes For Milk Waste Water Treatment, Alahmand Suleiman Mohammed
Electrochemical And Electroflotation Processes For Milk Waste Water Treatment, Alahmand Suleiman Mohammed
ETD Archive
The dairy industry generates abundant milk waste waters characterized by high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations that can be very harmful to the environment, if left untreated. Electrocoagulation (EC) has been in use for waste water treatment. The treatment application uses aluminum electrodes and iron or the combined hybrid Al/Fe electrodes. Milk waste water contains high concentration organic pollutants and the main constituents of those organics are carbohydrates, proteins and fats, originating from the milk. The process of separating the flocculated sludge from waste water that has been treated using the electrocoagulation process can be …
Walking Simulator Mechanism, Titus Lungu, Igor Tachynskyy, Omri Tayyara
Walking Simulator Mechanism, Titus Lungu, Igor Tachynskyy, Omri Tayyara
The Downtown Review
This paper presents the design, simulation, and kinematic evaluation of a mechanism aimed at simulating both the motion and ground reaction forces produced by a human foot while walking. Such a mechanism can be used to test the durability of shoes through life cycle analysis. In attempting to mimic the physical motion of the human foot as closely as possible, the forces experienced by the human foot were also accurately replicated through the incorporation of a non-stationary testing platform. As is shown in the paper, this testing environment allows for simple adjustments to be made in order to simulate different …
Assembly Level Clock Glitch Insertion Into An Xmega Mcu, Nigamantha Gopala Chakravarthi
Assembly Level Clock Glitch Insertion Into An Xmega Mcu, Nigamantha Gopala Chakravarthi
ETD Archive
This thesis proposes clock-glitch fault injection technique to inject glitches into the clock signal running in a microcontroller unit and studying its effects on different assembly level instructions. It focusses mainly on the effect of clock glitches over the execution, sub-execution and pre-execution cycles of the test instructions and also finds the delay between the actual position of glitch insertion and the trigger being set for the glitch insertion. The instructions used in this work are provided by Atmel which classifies them according to their type of operation. These instructions are here further grouped depending on the number of clock …
Specification Recommendation For Use Of High Performance Repair Material, Jennifer Woods
Specification Recommendation For Use Of High Performance Repair Material, Jennifer Woods
ETD Archive
The State of Ohio and the Ohio Department of Transportation (ODOT) have sought out ways to extend the life of the repair materials used by their construction crews, specifically, using high performance repair materials for the purposes of patching worn down or cracked sections of highways and bridge decks. Ohio is known for its frequent changes in weather, with freeze-thaw cycles occurring multiple times throughout the year. These cycles affect the lifespan of the repair material and create more maintenance for the DOT. Products that combat this problem were chosen, installed and examined over a year period to determine which …
The Behavior Of Simply Supported Plates Under Extreme Shear Loading, Mhd Ammar Hafez
The Behavior Of Simply Supported Plates Under Extreme Shear Loading, Mhd Ammar Hafez
ETD Archive
Steel plates are planar structural elements with one dimension significantly smaller than the others. These elements may fail due to either material yielding or buckling. Buckling is a sudden failure mode, which is not desirable in structural engineering applications. Buckling is called an “elastic buckling” when it happens before material yielding, and is termed as “plastic buckling” if it happens after material yielding. The focus of this thesis is on shear plates, which are plates that are primarily subjected to shear loads. Several studies were conducted to increase the elastic buckling capacity of plates by adding stiffeners to plates. However, …
Solute Partitioning In Elastin-Like Polypeptides: A Foundation For Drug Delivery Applications, Eric Helm
Solute Partitioning In Elastin-Like Polypeptides: A Foundation For Drug Delivery Applications, Eric Helm
ETD Archive
No abstract provided.
High Speed Clock Glitching, Santosh Desiraju
High Speed Clock Glitching, Santosh Desiraju
ETD Archive
In recent times, hardware security has drawn a lot of interest in the research community. With physical proximity to the target devices, various fault injection hardware attack methods have been proposed and tested to alter their functionality and trigger behavior not intended by the design. There are various types of faults that can be injected depending on the parameters being used and the level at which the device is tampered with. The literature describes various fault models to inject faults in clock of the target but there are no publications on overclocking circuits for fault injection. The proposed method bridges …
Numerical Investigation Of Boiling In A Sealed Tank In Microgravity, Sonya Lynn Hylton
Numerical Investigation Of Boiling In A Sealed Tank In Microgravity, Sonya Lynn Hylton
ETD Archive
NASA's missions in space depend on the storage of cryogenic fluids for fuel and for life support. During long-term storage, heat can leak into the cryogenic fluid tanks. Heat leaks can cause evaporation of the liquid, which pressurizes the tank. However, when the tanks are in a microgravity environment, with reduced natural convection, heat leaks can also create superheated regions in the liquid. This may lead to boiling, resulting in much greater pressure rises than evaporation at the interface between the liquid and vapor phases. Models for predicting the pressure rise are needed to aid in developing methods to control …
A Robotic Neuro-Musculoskeletal Simulator For Spine Research, Robb W. Colbrunn
A Robotic Neuro-Musculoskeletal Simulator For Spine Research, Robb W. Colbrunn
ETD Archive
An influential conceptual framework advanced by Panjabi represents the living spine as a complex neuromusculoskeletal system whose biomechanical functioning is rather finely dependent upon the interactions among and between three principal subsystems: the passive musculoskeletal subsystem (osteoligamentous spine plus passive mechanical contributions of the muscles), the active musculoskeletal subsystem (muscles and tendons), and the neural and feedback subsystem (neural control centers and feedback elements such as mechanoreceptors located in the soft tissues) [1]. The interplay between subsystems readily encourages "thought experiments" of how pathologic changes in one subsystem might influence another--for example, prompting one to speculate how painful arthritic changes …
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