Matching Items (8)
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- Creators: Electrical Engineering Program
- Creators: Arizona State University
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- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
In this thesis, an approach to develop low-frequency accelerometer based on molecular electronic transducers (MET) in an electrochemical cell is presented. Molecular electronic transducers are a class of inertial sensors which are based on an electrochemical mechanism. Motion sensors based on MET technology consist of an electrochemical cell that can be used to detect the movement of liquid electrolyte between electrodes by converting it to an output current. Seismometers based on MET technology are attractive for planetary applications due to their high sensitivity, low noise, small size and independence on the direction of sensitivity axis. In addition, the fact that MET based sensors have a liquid inertial mass with no moving parts makes them rugged and shock tolerant (basic survivability has been demonstrated to >20 kG).
A Zn-Cu electrochemical cell (Galvanic cell) was applied in the low-frequency accelerometer. Experimental results show that external vibrations (range from 18 to 70 Hz) were successfully detected by this accelerometer as reactions Zn→〖Zn〗^(2+)+2e^- occurs around the anode and 〖Cu〗^(2+)+2e^-→Cu around the cathode. Accordingly, the sensitivity of this MET device design is to achieve 10.4 V/G at 18 Hz. And the sources of noise have been analyzed.
A Zn-Cu electrochemical cell (Galvanic cell) was applied in the low-frequency accelerometer. Experimental results show that external vibrations (range from 18 to 70 Hz) were successfully detected by this accelerometer as reactions Zn→〖Zn〗^(2+)+2e^- occurs around the anode and 〖Cu〗^(2+)+2e^-→Cu around the cathode. Accordingly, the sensitivity of this MET device design is to achieve 10.4 V/G at 18 Hz. And the sources of noise have been analyzed.
ContributorsZhao, Zuofeng (Author) / Yu, Hongyu (Thesis advisor) / Zhang, Junshan (Committee member) / Jiang, Hanqing (Committee member) / Arizona State University (Publisher)
Created2015
Description
In many systems, it is difficult or impossible to measure the phase of a signal. Direct recovery from magnitude is an ill-posed problem. Nevertheless, with a sufficiently large set of magnitude measurements, it is often possible to reconstruct the original signal using algorithms that implicitly impose regularization conditions on this ill-posed problem. Two such algorithms were examined: alternating projections, utilizing iterative Fourier transforms with manipulations performed in each domain on every iteration, and phase lifting, converting the problem to that of trace minimization, allowing for the use of convex optimization algorithms to perform the signal recovery. These recovery algorithms were compared on a basis of robustness as a function of signal-to-noise ratio. A second problem examined was that of unimodular polyphase radar waveform design. Under a finite signal energy constraint, the maximal energy return of a scene operator is obtained by transmitting the eigenvector of the scene Gramian associated with the largest eigenvalue. It is shown that if instead the problem is considered under a power constraint, a unimodular signal can be constructed starting from such an eigenvector that will have a greater return.
ContributorsJones, Scott Robert (Author) / Cochran, Douglas (Thesis director) / Diaz, Rodolfo (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2014-05
Description
This document introduces the need for the Rest Egg system and defines an accessible method of smartphone integration. Excessive noise can prevent recovering patients and special needs persons from resting correctly. The Rest Egg was designed for these people- people who are in critical need of quality rest but are often unable to eliminate stressors themselves. This system ensures their environment is calm by alerting caretakers' smartphones if noise reaches abrasive levels. Smartphones were the preferred device due to the wide spread of such devices in today's market. After making open sourcing a goal, something ubiquitous and affordable \u2014 yet usable and dependable \u2014 was necessary for the alert system. These requirements lead to the election an online alert service: Pushover, a trademark and product of Superblock, LLC.
ContributorsJennings, Tyler Blake (Author) / Goryll, Michael (Thesis director) / Kozicki, Michael (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2016-05
Description
An investigation of phase noise in amplifier and voltage-controller oscillator (VCO) circuits was conducted to show that active direct-current (DC) bias techniques exhibit lower phase noise performance than traditional resistive DC bias techniques. Low-frequency high-gain amplifiers like those found in audio applications exhibit much better 1/f phase noise performance and can be used to bias amplifier or VCO circuits that work at much higher frequencies to reduce the phase modulation caused by higher frequency devices. An improvement in single-side-band (SSB) phase noise of 15 dB at offset frequencies less than 50 KHz was simulated and measured. Residual phase noise of an actively biased amplifier also exhibited significant noise improvements when compared to an equivalent resistive biased amplifier.
ContributorsBaldwin, Jeremy Bart (Author) / Aberle, James T., 1961- (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2010
Description
This paper analyzes existing literature regarding how excessive aggravating stimuli in a hospital environment can reduce the quality and quantity of sleep. The sick and injured are most sensitive to aggravating stimuli and the most vulnerable to poor sleep conditions. For individuals with anxiety, stress, hypersensitivity, or conditions such as Autism Spectrum Disorder (ASD), as additional stress during rest periods could seriously harm development and overall well-being. While solutions have been proposed and tested, there is no one solution to the problem. One possible solution is to design a device that monitors a patient's room and alerts a nurse or parent of aggravating stimuli so that it can be removed.
ContributorsKhan, Zarah Noor (Author) / Goryll, Michael (Thesis director) / Adams, James B. (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The honors thesis presented in this document describes an extension to an electrical engineering capstone project whose scope is to develop the receiver electronics for an RF interrogator. The RF interrogator functions by detecting the change in resonant frequency of (i.e, frequency of maximum backscatter from) a target resulting from an environmental input. The general idea of this honors project was to design three frequency selective surfaces that would act as surrogate backscattering or reflecting targets that each contains a distinct frequency response. Using 3-D electromagnetic simulation software, three surrogate targets exhibiting bandpass frequency responses at distinct frequencies were designed and presented in this thesis.
ContributorsSisk, Ryan Derek (Author) / Aberle, James (Thesis director) / Chakraborty, Partha (Committee member) / Electrical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
In a Mirror Dimly… is an autobiographical work that follows my mental development from my teen years into my mid-20s and offers a way forward into the future. First comes legalism: a canon, which represents a rule-based thought process. Next is freedom and individuality: indeterminate methods and textures. Finally, the piece concludes with unity and wholeness, using quoted and composed hymns in chorale settings. The conceptual content is taken from Hermann Hesse’s Siddhartha, a story of a Hindu man’s life through the development of his own ideology into Buddhism. He begins by following the rules of his faith obsessively, then he decides that the rules themselves don’t matter as much as the spirit behind them, and finally he begins to see the interconnectedness of nature through the flow of a river and gains a fuller picture of all that is. I have also included an anxiety motif which begins as an interruption or nuisance; it then takes over in the form of a panic attack but is quelled by a hymn: “Be Still My Soul,” with text written by Katharina von Schlegel set to the tune of Sibelius’ Finlandia. Finally, the anxiety is contained and molded to help the overall texture rather than disrupting it. The anxiety is never truly eradicated, but it is transformed.
ContributorsChesney, Jacob Andrew (Author) / Temple, Alex (Thesis advisor) / Bolanos, Gabriel (Committee member) / Rockmaker, Jody (Committee member) / Arizona State University (Publisher)
Created2022
Description
The ability of magnetic resonance imaging (MRI) to image any part of the human body without the effects of harmful radiation such as in CAT and PET scans established MRI as a clinical mainstay for a variety of different ailments and maladies. Short wavelengths accompany the high frequencies present in high-field MRI, and are on the same scale as the human body at a static magnetic field strength of 3 T (128 MHz). As a result of these shorter wavelengths, standing wave effects are produced in the MR bore where the patient is located. These standing waves generate bright and dark spots in the resulting MR image, which correspond to irregular regions of high and low clarity. Coil loading is also an inevitable byproduct of subject positioning inside the bore, which decreases the signal that the region of interest (ROI) receives for the same input power. Several remedies have been proposed in the literature to remedy the standing wave effect, including the placement of high permittivity dielectric pads (HPDPs) near the ROI. Despite the success of HPDPs at smoothing out image brightness, these pads are traditionally bulky and take up a large spatial volume inside the already small MR bore. In recent years, artificial periodic structures known as metamaterials have been designed to exhibit specific electromagnetic effects when placed inside the bore. Although typically thinner than HPDPs, many metamaterials in the literature are rigid and cannot conform to the shape of the patient, and some are still too bulky for practical use in clinical settings. The well-known antenna engineering concept of fractalization, or the introduction of self-similar patterns, may be introduced to the metamaterial to display a specific resonance curve as well as increase the metamaterial’s intrinsic capacitance. Proposed in this paper is a flexible fractal-inspired metamaterial for application in 3 T MR head imaging. To demonstrate the advantages of this flexibility, two different metamaterial configurations are compared to determine which produces a higher localized signal-to-noise ratio (SNR) and average signal measured in the image: in the first configuration, the metamaterial is kept rigid underneath a human head phantom to represent metamaterials in the literature (single-sided placement); and in the second, the metamaterial is wrapped around the phantom to utilize its flexibility (double-sided placement). The double-sided metamaterial setup was found to produce an increase in normalized SNR of over 5% increase in five of six chosen ROIs when compared to no metamaterial use and showed a 10.14% increase in the total average signal compared to the single-sided configuration.
ContributorsSokol, Samantha (Author) / Sohn, Sung-Min (Thesis director) / Allee, David (Committee member) / Jones, Anne (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2022-05