Now showing items 5820-5839 of 15436

    • Fabrication and modeling of a floating-gate transistor for use as an electrostatic-discharge detector

      Schrimpf, Ron D.; Hsueh, Weichung Paul, 1962- (The University of Arizona., 1988)
      Electrostatic discharge is of great concern to the electronics industry. It degrades and destroys large numbers of integrated circuits at every step from fabrication through packaging and testing. The goal of this research effort was the development of a device that can be used to obtain quantitative information on electrostatic discharge (ESD) in the integrated-circuit workplace. The device that was developed can be utilized in two different modes. (1) It can be used to form ESD test wafers or test chips. (2) It can be incorporated on product chips to give the ESD history of devices or monitor the process line. The technology that was examined in this work was that for floating-gate PROMS. A simple analytical model for obtaining a parameter called the ESD factor was developed. The prototype detector was designed, fabricated and tested in the Semiconductor Processing Facility of the University of Arizona. Evidence will be presented that the FLOTOX type of EEPROM functions well in its application as an ESD detector.
    • Fabrication and Testing of Computer Generated Holograms Using the MLA 150

      Milster, Thomas D.; Purvin, Kira; Kim, Daewook; Kim, Youngsik (The University of Arizona., 2021)
      Grayscale lithography is a powerful technique that makes it possible to fabricate three-dimensional microstructures in photoresist. This thesis presents a newly developed process for achieving high quality grayscale lithography using the MLA 150 as well as initial results for various applications. Multiple photoresists including S1813, S1827 and AZ P4620 are characterized to provide a foundation for the developed fabrication process. A linearization regime is also presented that calibrates the MLA 150’s nominal grayscale output such that a result displaying equally spaced gray layers is achieved. The final grayscale lithography process is applied to fabricate a computer generated hologram (CGH) for use in adaptive optics for phase retrieval. A replication process is detailed that enables the exposed patterns to be replicated in NOA61 to form a usable and semi-permanent optical element. Comparisons made between the fabricated optical elements and the original designs demonstrate the success of the fabrication process.
    • Fabrication of a micro-Fresnel lens on a spherical substrate

      Milster, Thomas D.; Trusty, Robert Mason, 1959- (The University of Arizona., 1990)
      A decrease in the size and weight of the objective lens in an optical data storage system (ODS) would improve performance. Limits on reducing the lens size were investigated. Size reduction is limited by aberrations introduced by the disk cover plate that protects the recording medium from dust and scratches. Size reduction is also limited by off-axis aberrations introduced by beam tilt required to maintain a field of view similar to conventional ODS objectives. It was shown that a Fresnel microlens on a thin spherical shell is acomatic for all field angles. A technique used to fabricate such a lens was demonstrated. The resulting lens was presented.
    • Fabrication of micro-optics using binary and graylevel masks

      Descour, Michael; Simon, Daniel I, 1971- (The University of Arizona., 1998)
      This thesis provides step by step instructions on how to design, layout, and fabricate diffractive optical elements (DOE). While there has been a great deal published on the design of DOEs, there are few publications detailing how to transform a design into a physical element. The thesis describes how to order a photomask and pattern an element. It provides recipes that I have used to etch DOEs with both an ion mill and a reactive ion etcher (RIE) at the Optical Sciences Center. The thesis includes characterization of the elements fabricated using these recipes. In addition the thesis looks at the design and fabrication of ring toric lenslets. A ring toric lenslet is a DOE that focuses light to a ring instead of a point. The ring toric lenslet has potential applications in the optical data storage industry. This thesis includes macros for the design and mask layout of binary and grayscale ring toric lenslets. Grayscale elements require special design, calibration, and mask layout steps not necessary for binary elements. Details of the design, calibration, mask layout, and fabrication of the grayscale element are included.
    • Fabrication of Polystyrene Core-Silica Shell Nanoparticles for Scintillation Proximity Assay (SPA) Biosensors

      Aspinwall, Craig A.; Noviana, Eka; Heien, Michael L.; Pyun, Jeffrey (The University of Arizona., 2015)
      The development of analytical tools for investigating biological pathways on the molecular level has provided insight into diseases and disorders. However, many biological analytes such as glucose and inositol phosphate(s) lack the optical or electrochemical properties needed for detection, making molecular sensing challenging. Scintillation proximity assay (SPA) does not require analytes to possess such properties. SPA uses radioisotopes to monitor the binding of analytes to SPA beads. The beads contain scintillants that emit light when the radiolabeled analytes are in close proximity. This technique is rapid, sensitive and separation-free. Conventional SPA beads, however, are large relative to the cells and made of hydrophobic organic polymers that tend to aggregate or inorganic crystals that sediment rapidly in aqueous solution, thus limiting SPA applications. To overcome these problems, polystyrene core-silica shell nanoparticles (NPs) doped with pTP and dimethyl POPOP were fabricated to produce scintillation NPs that emit photons in the blue region of visible light. The developed scintillation particles are approximately 250 nm in diameter (i.e. 200 nm of core diameter and 10-30 nm of shell thickness), responsive to β-decay from tritium (³H) and have sufficient stability in the aqueous media. DNA hybridization-based SPA was performed to determine whether the scintillation NPs could be utilized for SPA applications. A 30-mer oligonucleotide was immobilized on the polystyrene core-silica shell NPs to give approximately 7.6 x 10³ oligonucleotide molecules per NP and ³H-labeled complementary strand was annealed to the immobilized strand. At the saturation point, increases in scintillation signal due to oligonucleotide binding to the NPs were about 9 fold compared to the control experiments in which no specific binding occurred, demonstrating that the scintillation NPs can be utilized for SPA. Along with the improved physical properties including smaller size and better stability in the aqueous system, the developed scintillation NPs could be potentially useful as biosensors in cellular studies.
    • Fabrication of textured surface solar cells with the help of anisotropic etching

      Dixit, Suresh Gopal, 1946- (The University of Arizona., 1977)
    • Facilitating disclosure in psychologically abused women

      Phillips, Linda R.; Harrison, Eileen Joselyn, 1940- (The University of Arizona., 1998)
      The purpose of this study was to identify from the woman's point of view what factors facilitate or inhibit disclosure of psychological abuse. Physical and psychological symptoms arise from this abuse and women are reluctant to disclose the underlying cause. This is a significant problem for every specialty in the nursing profession. A qualitative study using grounded theory was conducted with four research participants from domestic violence shelters. The results suggest contextual and behavioral factors in the disclosure process and give descriptive supporting data of related concepts. A conceptual model for the disclosure process is proposed.
    • Facilitating Feminist Ethics Consultations: A Legal Solution to Encourage Innovative Ethical Analysis

      Wyman, Jamie L; Croissant, Jennifer (The University of Arizona., 2008)
      This thesis aims to make feminist theory an integral part of hospital ethics committee ("HEC") decisionmaking. Specifically, the feminist theories discussed in this thesis prioritize an awareness of social context. The small-scale study conducted for this thesis found that HECs already consider social context to some extent but that they may also be open to more systematic integration. As opposed to courts, HECs provide a space where innovative alternatives (e.g., feminist approaches) to principalist bioethical decisionmaking can be tested. In order to encourage the development of such alternatives, this thesis has proposed a framework for the relationship between courts and HECs so that patients can benefit from the strengths of both entities in ways that have not been possible in the past.
    • Facilitation of performance on a picture fragment completion test: Data-driven potentiation in perception

      Peterson, Mary A.; Merikle, Elizabeth Paige, 1965- (The University of Arizona., 1991)
      A technique commonly used to study the structure of memory entails preceding a task by a brief masked presentation of a potentially relevant stimulus. In two experiments, I examined the type of facilitation obtained on a picture fragment completion task by prior presentation of either the name of the completed object, a complete picture of the object, or the fragment itself. In Experiment 1a significantly more ambiguous picture fragments (i.e. fragments supporting a number of interpretations) were identified after exposure to pictures than to picture names or picture fragments. Experiment 1b verified that the information in the masked primes was not available to conscious awareness. These results suggest that under limited encoding conditions only bottom-up activation provided by prior presentation of the fragments aids shape recognition under degraded conditions. Implications for the structures and processes involved in shape recognition are discussed.
    • Factionalism among the Kiowa-Apaches

      Daza, Marjorie Duffus Melvin, 1940- (The University of Arizona., 1968)
    • A factor analytic study of impulsivity and creative abilities

      Pacuilla, Nicholas, 1940- (The University of Arizona., 1971)
    • The Factor of Time in the Analysis and Interpretation of Cultural Landscapes

      Erickson, Helen Breslich; Johnson, Lauri MacMillan; Jeffery, R. Brooks; O'Brien, William Patrick (The University of Arizona., 2012)
      Cultural landscapes - artifacts that display the combined work of man and nature - exist in time. Therefore their evaluation, analysis and interpretation must take place within the context of conscious or unconscious understandings of time/space relationships. Landscape architecture professionals are often wary of the preservation of historic landscapes, sensing that a living landscape cannot be frozen in time. Heritage conservationists, working within structures initially designed to serve the built environment, sometimes question the validity of a dynamic landscape as a heritage resource. Divergent developmental histories led these two disciplines to internalize distinctive understandings of the meaning of time, giving rise in the process to conflicting yet potentially complementary conservation metrics. A discussion of these separate histories and resulting concepts of time will provide a starting point for an interdisciplinary discussion about a shared resource viewed through two contrasting temporal lenses. Case studies, examined in the context of frameworks devised by the National Park Service (NPS) for the analysis of cultural resources, suggest ways to expand the existing methodology to take conscious advantage of both of these views of time. The insights of landscape architecture offer a richer, more comprehensive view of an important heritage resource, while existing NPS structures offer a recognized means of validation and support for the conservation of cultural landscapes.
    • Factors Affecting Agricultural Water Use and Sourcing in Irrigation Districts of Central Arizona

      Colby, Bonnie; Fleck, Brett E.; Thompson, Gary D.; Wilson, Paul N. (The University of Arizona., 2013)
      The purpose of this research is to quantify how macro-scale factors such as weather, crop prices, and land conversion affect agricultural water use at the irrigation district level in central Arizona and to understand what constraints and considerations district managers face when making water-sourcing decisions. A conceptual model is developed and econometrically estimated finding that much of the annual variation in total water use for agriculture can be explained by differences in precipitation, cotton prices, and alfalfa prices. Further, results from empirical analysis support the notion that total water use for agriculture has been greatly affected by land conversion from agriculture to other uses. Irrigation district manager interviews indicate that the water sourcing process is very similar across districts in central Arizona and has varied little since 1995, due to common constraints. This research lays an important foundation for future models designed to forecast agricultural water use in central Arizona.
    • Factors affecting diffusion of atmospheric fluorocarbons into unsaturated porous materials

      Earp, Douglas E. (Douglas Eugene) (The University of Arizona., 1981)
    • Factors affecting diffusion of atmospheric fluorocarbons into unsaturated porous materials

      Earp, Douglas E.(Douglas Eugene); Thompson, Glenn M. (The University of Arizona., 1981)
      Atmospheric buildup of two fluorocarbon gases, CC1₃F (F-11) and CC1₂F₂ (F-12), during the past forty years has been documented by previous workers. The present study involved measurements of F-11 and F-12 concentrations in soil air within unconsolidated porous materials. Measurable concentrations of both gases were found at depths as great as forty-four meters at field sites near Lubbock, Texas. Agreement between measured concentrations and concentrations predicted using mathematical models based on molecular diffusion theory suggests that gaseous diffusion was the primary mechanism by which atmospheric fluorocarbons were transported within the subsurface. Analytical models were employed to derive effective diffusion coefficients of F-11 and F-12 under field conditions (0.005 cm²/sec. and 0.012 cm²/sec., respectively) and under controlled laboratory conditions (0.017 cm²/sec. for F-11 and 0.021 cm²/sec. for F-12). A finite difference model was used to estimate in situ tortuosity values (mean = 0.10) for unsaturated porous materials at one field site.