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Description
The object of this study is to charac terize the effect of focused ultrasound stimulation (FUS) on the rat ce rvix which has been observed to speed its ripening during pregnancy. Ce rvical ripening is required for successful fetal delivery. Timed-pregnant Sprague-Dawley rats (n=36) were used. On day 14 of gestation, the FUS system was placed on the body surface of the rat over the cervix and ultrasound energy was applied to cervix for variable times up to 1 hour in the control group, the FUS system was placed on rats but no energy was applied. Daily measurement of cervix light-induced florescence (LIF, photon counts of collagen x-bridge fluorescence) were made on days 16 of gestation and daily until spont-aneous delivery (day22) to estimate changes in cervical ripening. We found that pulses of 680 KHz ultrasound at 25 Hertz, 1 millisecond pulse duration at 1W/cm^2 applied for as little as 30 minutes would immediately afterwards show the cervix to hav e ripened to the degree seen just before delivery on day 22. Delivery times, fetal weights and viability were unaffected in the FUS-treated animals.
ContributorsLuo, Daishen (Author) / Towe, Bruce C (Thesis advisor) / Wang, Xiao (Committee member) / Caplan, Michael (Committee member) / Arizona State University (Publisher)
Created2012
Description
The goal of this research study was to identify the competencies the Project Manager (PM) will need to respond to the challenges the construction industry faces in 2022 and beyond. The study revealed twenty-one emerging challenges for construction PMs grouped into four primary disruptive forces: workforce demographics, globalization, rapidly evolving technology, and changing organizational structures. The future PM will respond to these emerging challenges using a combination of fourteen competencies. The competencies are grouped into four categories: technical (multi-disciplined, practical understanding of technology), management (keen business insight, understanding of project management, knowledge network building, continuous risk monitoring), cognitive (complex decisions making, emotional maturity, effective communication), and leadership (leveraging diverse thinking, building relationships, engaging others, mentoring, building trust). Popular data collection methods used in project management research, such as surveys and interviews, have received criticism about the differences between stated responses to questions, what respondents say they will do, and revealed preferences, what they actually practice in the workplace. Rather than relying on surveys, this research study utilized information generated from games and exercises bundled into one-day training seminars conducted by Construction Industry Institute (CII) companies for current and upcoming generations of PMs. Educational games and exercises provide participants with the opportunity to apply classroom learning and workplace experience to resolve issues presented in real-world scenarios, providing responses that are more closely aligned with the actual decisions and activities occurring on projects. The future competencies were identified by combining results of the literature review with information from the games and exercises through an iterative cycle of data mining, analysis, and consolidation review sessions with CII members. This competency forecast will be used as a basis for company recruiting and to create tools for professional development programs and project management education at the university level. In addition to the competency forecast, the research identified simulation games and exercises as components of a project management development program in a classroom setting. An instrument that links the emerging challenges with the fourteen competencies and learning tools that facilitate the mastering of these competencies has also been developed.
ContributorsKing, Cynthia Joyce (Author) / Wiezel, Avi (Thesis advisor) / Badger, William (Committee member) / Sullivan, Kenneth (Committee member) / Arizona State University (Publisher)
Created2012
Description
Scaling of the classical planar MOSFET below 20 nm gate length is facing not only technological difficulties but also limitations imposed by short channel effects, gate and junction leakage current due to quantum tunneling, high body doping induced threshold voltage variation, and carrier mobility degradation. Non-classical multiple-gate structures such as double-gate (DG) FinFETs and surrounding gate field-effect-transistors (SGFETs) have good electrostatic integrity and are an alternative to planar MOSFETs for below 20 nm technology nodes. Circuit design with these devices need compact models for SPICE simulation. In this work physics based compact models for the common-gate symmetric DG-FinFET, independent-gate asymmetric DG-FinFET, and SGFET are developed. Despite the complex device structure and boundary conditions for the Poisson-Boltzmann equation, the core structure of the DG-FinFET and SGFET models, are maintained similar to the surface potential based compact models for planar MOSFETs such as SP and PSP. TCAD simulations show differences between the transient behavior and the capacitance-voltage characteristics of bulk and SOI FinFETs if the gate-voltage swing includes the accumulation region. This effect can be captured by a compact model of FinFETs only if it includes the contribution of both types of carriers in the Poisson-Boltzmann equation. An accurate implicit input voltage equation valid in all regions of operation is proposed for common-gate symmetric DG-FinFETs with intrinsic or lightly doped bodies. A closed-form algorithm is developed for solving the new input voltage equation including ambipolar effects. The algorithm is verified for both the surface potential and its derivatives and includes a previously published analytical approximation for surface potential as a special case when ambipolar effects can be neglected. The symmetric linearization method for common-gate symmetric DG-FinFETs is developed in a form free of the charge-sheet approximation present in its original formulation for bulk MOSFETs. The accuracy of the proposed technique is verified by comparison with exact results. An alternative and computationally efficient description of the boundary between the trigonometric and hyperbolic solutions of the Poisson-Boltzmann equation for the independent-gate asymmetric DG-FinFET is developed in terms of the Lambert W function. Efficient numerical algorithm is proposed for solving the input voltage equation. Analytical expressions for terminal charges of an independent-gate asymmetric DG-FinFET are derived. The new charge model is C-infinity continuous, valid for weak as well as for strong inversion condition of both the channels and does not involve the charge-sheet approximation. This is accomplished by developing the symmetric linearization method in a form that does not require identical boundary conditions at the two Si-SiO2 interfaces and allows for volume inversion in the DG-FinFET. Verification of the model is performed with both numerical computations and 2D TCAD simulations under a wide range of biasing conditions. The model is implemented in a standard circuit simulator through Verilog-A code. Simulation examples for both digital and analog circuits verify good model convergence and demonstrate the capabilities of new circuit topologies that can be implemented using independent-gate asymmetric DG-FinFETs.
ContributorsDessai, Gajanan (Author) / Gildenblat, Gennady (Committee member) / McAndrew, Colin (Committee member) / Cao, Yu (Committee member) / Barnaby, Hugh (Committee member) / Arizona State University (Publisher)
Created2012
Description
Zinc oxide (ZnO) has attracted much interest during last decades as a functional material. Furthermore, ZnO is a potential material for transparent conducting oxide material competing with indium tin oxide (ITO), graphene, and carbon nanotube film. It has been known as a conductive material when doped with elements such as indium, gallium and aluminum. The solubility of those dopant elements in ZnO is still debatable; but, it is necessary to find alternative conducting materials when their form is film or nanostructure for display devices. This is a consequence of the ever increasing price of indium. In addition, a new generation solar cell (nanostructured or hybrid photovoltaics) requires compatible materials which are capable of free standing on substrates without seed or buffer layers and have the ability introduce electrons or holes pathway without blocking towards electrodes. The nanostructures for solar cells using inorganic materials such as silicon (Si), titanium oxide (TiO2), and ZnO have been an interesting topic for research in solar cell community in order to overcome the limitation of efficiency for organic solar cells. This dissertation is a study of the rational solution-based synthesis of 1-dimentional ZnO nanomaterial and its solar cell applications. These results have implications in cost effective and uniform nanomanufacturing for the next generation solar cells application by controlling growth condition and by doping transition metal element in solution.
ContributorsChoi, Hyung Woo (Author) / Alford, Terry L. (Thesis advisor) / Krause, Stephen (Committee member) / Theodore, N. David (Committee member) / Arizona State University (Publisher)
Created2012
Description
Trenchless technology is a group of techniques whose utilization allows for the installation, rehabilitation, and repair of underground infrastructure with minimal excavation from the ground surface. As the built environment becomes more congested, projects are trending towards using trenchless technologies for their ability to quickly produce a quality product with minimal environmental and social costs. Pilot tube microtunneling (PTMT) is a trenchless technology where new pipelines may be installed at accurate and precise line and grade over manhole to manhole distances. The PTMT process can vary to a certain degree, but typically involves the following three phases: jacking of the pilot tube string to achieve line and grade, jacking of casing along the pilot bore and rotation of augers to excavate the borehole to a diameter slightly larger than the product pipe, and jacking of product pipe directly behind the last casing. Knowledge of the expected productivity rates and jacking forces during a PTMT installation are valuable tools that can be used for properly weighing its usefulness versus competing technologies and minimizing risks associated with PTMT. This thesis outlines the instrumentation and monitoring process used to record jacking frame hydraulic pressures from seven PTMT installations. Cyclic patterns in the data can be detected, indicating the installation of a single pipe segment, and enabling productivity rates for each PTMT phase to be determined. Furthermore, specific operations within a cycle, such as pushing a pipe or retracting the machine, can be observed, allowing for identification of the critical tasks associated with each phase. By identifying the critical tasks and developing more efficient means for their completion, PTMT productivity can be increased and costs can be reduced. Additionally, variations in depth of cover, drive length, pipe diameter, and localized ground conditions allowed for trends in jacking forces to be identified. To date, jacking force predictive models for PTMT are non-existent. Thus, jacking force data was compared to existing predictive models developed for the closely related pipe jacking and microtunneling methodologies, and the applicability of their adoption for PTMT jacking force prediction was explored.
ContributorsOlson, Matthew P (Author) / Ariaratnam, Samuel T (Thesis advisor) / Lueke, Jason S (Committee member) / Zapata, Claudia E (Committee member) / Tang, Pingbo (Committee member) / Arizona State University (Publisher)
Created2013
Description
Alzheimer's disease (AD) is the leading neurodegenerative disease, affecting roughly 8% of people 65 years of age or older. There exists an imperative need to develop a non-invasive test for the earlier detection of AD. The use of biomarkers is a promising option that examines the toxic mechanisms and metabolic pathways that cause Alzheimer's disease, eventually leading to an early diagnostic method. This thesis presents the use of oligomeric beta-amyloid as a biomarker to detect Alzheimer's disease via a specialized enzyme-linked protein assay. Specifically, this paper details the optimization and development of a novel phage capture enzyme-linked immunosorbent assay (ELISA) that can detect the relative quantity of beta-amyloid oligomers in samples from a mouse model of AD. The objective of this thesis was to optimize a phage capture ELISA using the A4 single-chain variable fragment (scFv) to quantify the amount of beta-amyloid oligomers in various mice samples. A4 selectively recognizes a toxic oligomeric form of beta-amyloid. The level of A4-reactive oligomeric beta-amyloid was measured in triplicate in homogenized mouse brain tissue samples from eight transgenic (TG) and eight nontransgenic (NTG) animals aged five, nine, and thirteen months. There was a significant difference (p < 0.0005) between the five month TG and NTG mice. A decrease in beta-amyloid levels with the aging of the TG mice suggested that the beta-amyloid oligomers may be aggregating to form beta-amyloid fibrils. Conversely, the quantity of beta-amyloid increased with the aging of the NTG mice. This indicated that beta-amyloid oligomers may develop with normal aging.
ContributorsBrownlee, Taylor (Author) / Sierks, Michael (Thesis advisor) / Williams, Stephanie (Committee member) / Xin, Wei (Committee member) / Arizona State University (Publisher)
Created2013
Description
Gene manipulation techniques, such as RNA interference (RNAi), offer a powerful method for elucidating gene function and discovery of novel therapeutic targets in a high-throughput fashion. In addition, RNAi is rapidly being adopted for treatment of neurological disorders, such as Alzheimer's disease (AD), Parkinson's disease, etc. However, a major challenge in both of the aforementioned applications is the efficient delivery of siRNA molecules, plasmids or transcription factors to primary cells such as neurons. A majority of the current non-viral techniques, including chemical transfection, bulk electroporation and sonoporation fail to deliver with adequate efficiencies and the required spatial and temporal control. In this study, a novel optically transparent biochip is presented that can (a) transfect populations of primary and secondary cells in 2D culture (b) readily scale to realize high-throughput transfections using microscale electroporation and (c) transfect targeted cells in culture with spatial and temporal control. In this study, delivery of genetic payloads of different sizes and molecular characteristics, such as GFP plasmids and siRNA molecules, to precisely targeted locations in primary hippocampal and HeLa cell cultures is demonstrated. In addition to spatio-temporally controlled transfection, the biochip also allowed simultaneous assessment of a) electrical activity of neurons, b) specific proteins using fluorescent immunohistochemistry, and c) sub-cellular structures. Functional silencing of GAPDH in HeLa cells using siRNA demonstrated a 52% reduction in the GAPDH levels. In situ assessment of actin filaments post electroporation indicated a sustained disruption in actin filaments in electroporated cells for up to two hours. Assessment of neural spike activity pre- and post-electroporation indicated a varying response to electroporation. The microarray based nature of the biochip enables multiple independent experiments on the same culture, thereby decreasing culture-to-culture variability, increasing experimental throughput and allowing cell-cell interaction studies. Further development of this technology will provide a cost-effective platform for performing high-throughput genetic screens.
ContributorsPatel, Chetan (Author) / Muthuswamy, Jitendran (Thesis advisor) / Helms Tillery, Stephen (Committee member) / Jain, Tilak (Committee member) / Caplan, Michael (Committee member) / Vernon, Brent (Committee member) / Arizona State University (Publisher)
Created2012
Description
The use of electromyography (EMG) signals to characterize muscle fatigue has been widely accepted. Initial work on characterizing muscle fatigue during isometric contractions demonstrated that its frequency decreases while its amplitude increases with the onset of fatigue. More recent work concentrated on developing techniques to characterize dynamic contractions for use in clinical and training applications. Studies demonstrated that as fatigue progresses, the EMG signal undergoes a shift in frequency, and different physiological mechanisms on the possible cause of the shift were considered. Time-frequency processing, using the Wigner distribution or spectrogram, is one of the techniques used to estimate the instantaneous mean frequency and instantaneous median frequency of the EMG signal using a variety of techniques. However, these time-frequency methods suffer either from cross-term interference when processing signals with multiple components or time-frequency resolution due to the use of windowing. This study proposes the use of the matching pursuit decomposition (MPD) with a Gaussian dictionary to process EMG signals produced during both isometric and dynamic contractions. In particular, the MPD obtains unique time-frequency features that represent the EMG signal time-frequency dependence without suffering from cross-terms or loss in time-frequency resolution. As the MPD does not depend on an analysis window like the spectrogram, it is more robust in applying the timefrequency features to identify the spectral time-variation of the EGM signal.
ContributorsAustin, Hiroko (Author) / Papandreou-Suppappola, Antonia (Thesis advisor) / Kovvali, Narayan (Committee member) / Muthuswamy, Jitendran (Committee member) / Arizona State University (Publisher)
Created2012
Description
Ball Grid Array (BGA) using lead-free or lead-rich solder materials are widely used as Second Level Interconnects (SLI) in mounting packaged components to the printed circuit board (PCB). The reliability of these solder joints is of significant importance to the performance of microelectronics components and systems. Product design/form-factor, solder material, manufacturing process, use condition, as well as, the inherent variabilities present in the system, greatly influence product reliability. Accurate reliability analysis requires an integrated approach to concurrently account for all these factors and their synergistic effects. Such an integrated and robust methodology can be used in design and development of new and advanced microelectronics systems and can provide significant improvement in cycle-time, cost, and reliability. IMPRPK approach is based on a probabilistic methodology, focusing on three major tasks of (1) Characterization of BGA solder joints to identify failure mechanisms and obtain statistical data, (2) Finite Element analysis (FEM) to predict system response needed for life prediction, and (3) development of a probabilistic methodology to predict the reliability, as well as, the sensitivity of the system to various parameters and the variabilities. These tasks and the predictive capabilities of IMPRPK in microelectronic reliability analysis are discussed.
ContributorsFallah-Adl, Ali (Author) / Tasooji, Amaneh (Thesis advisor) / Krause, Stephen (Committee member) / Alford, Terry (Committee member) / Jiang, Hanqing (Committee member) / Mahajan, Ravi (Committee member) / Arizona State University (Publisher)
Created2013
Description
While the piezoelectric effect has been around for some time, it has only recently caught interest as a potential sustainable energy harvesting device. Piezoelectric energy harvesting has been developed for shoes and panels, but has yet to be integrated into a marketable bicycle tire. For this thesis, the development and feasibility of a piezoelectric tire was done. This includes the development of a circuit that incorporates piezoceramic elements, energy harvesting circuitry, and an energy storage device. A single phase circuit was designed using an ac-dc diode rectifier. An electrolytic capacitor was used as the energy storage device. A financial feasibility was also done to determine targets for manufacturing cost and sales price. These models take into account market trends for high performance tires, economies of scale, and the possibility of government subsidies. This research will help understand the potential for the marketability of a piezoelectric energy harvesting tire that can create electricity for remote use. This study found that there are many obstacles that must be addressed before a piezoelectric tire can be marketed to the general public. The power output of this device is miniscule compared to an alkaline battery. In order for this device to approach the power output of an alkaline battery the weight of the device would also become an issue. Additionally this device is very costly compared to the average bicycle tire. Lastly, this device is extreme fragile and easily broken. In order for this device to become marketable the issues of power output, cost, weight, and durability must all be successfully overcome.
ContributorsMalotte, Christopher (Author) / Madakannan, Arunachalanadar (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2012