• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1925
  • 1546
  • 402
  • 59
  • 43
  • 31
  • 27
  • 12
  • 7
  • 6
  • 6
  • 4
  • 4
  • 4
  • 4
  • Tagged with
  • 4525
  • 2849
  • 2489
  • 2402
  • 2307
  • 2281
  • 2269
  • 967
  • 738
  • 616
  • 593
  • 552
  • 542
  • 418
  • 349
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The process of participating in academic interdisciplinary health services team research a grounded theory investigation /

Galt, Kimberly A. January 2009 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed July 22, 2010). PDF text: xvii, 307 p. : ill. ; 2 Mb. UMI publication number: AAT 3386837. Includes bibliographical references. Also available in microfilm and microfiche formats.
22

Perceptions of Collaboration and Mutual Respect Among Members of Interprofessional Teams

Lankhof, Brenda 01 January 2018 (has links)
Government agencies are encouraging healthcare practitioners to work in interprofessional teams to address the complex needs of an aging population, to improve client outcomes, and to increase the cost-effectiveness of health care. However, a clearer understanding of the elements required for an effective interprofessional collaborative practice is needed. The purpose of this online, descriptive study was to focus on one component, mutual respect, and determine its relationship to collaboration among members of interprofessional teams working in family health teams (FHTs) and community health centers (CHCs) across Ontario. D'Amour's four-dimensional model of collaboration was used as the theoretical basis. This model suggests that collective action can be analyzed based on shared goals and vision, internalization, formalization, and governance. FHTs and CHCs were contacted by telephone and email to recruit participants and 99 healthcare professionals returned usable surveys. Using Spearman's rho and multiple regression, a significant positive relationship was found between mutual respect and collaboration. After controlling for the respondents' demographic characteristics, the correlation between these variables remained significant. Correlation scores between mutual respect and collaboration were higher in FHTs compared to CHCs. Significant differences in scores were also demonstrated between nurses and nonurses, and levels of education. This research provided data on how collaboration is progressing, how respected professionals felt, and assisted in the identification of areas that may be influential in making improvements. The knowledge obtained can affect positive social change by influencing practice, education, and guiding future research.
23

Phototunable Mechanical Properties of Azobenzene-Containing Hydrogels

Baer, Bradly 03 August 2016 (has links)
The mechanical properties of the extracellular matrix are dynamic and change during biological processes such as disease progression and wound healing. Most synthetic (or man-made) tissue scaffolds have static properties. Therefore it is necessary to replate cells in order to determine the effects that different matrix mechanical properties have on cells, and virtually impossible to study the effects of a dynamically changing modulus on cell growth. There have been several scaffolds recently developed with tunable mechanical properties, but few exhibit any reversibility which is important for simulating repeated wounding and healing cycles. In this work, we develop a gelatin based hydrogel with azodianiline (ADA) as a secondary crosslinking unit. Upon irradiation with 365 nm light the gel softens as the ADA undergoes a photoisomerization. These changes can be reversed upon exposure to visible light. With applications in mechanobiology in mind, contraction at the cellular scale was measured, as well as the macroscopic changes in the shear elastic modulus and compressive modulus in response to exposure to UV and visible light.
24

Hospice Interdisciplinary Team Processes and Effectiveness

Hale, Beth Ann January 2007 (has links)
The purpose of this research was to test a causal model of interdisciplinary hospice processes and effectiveness. This research examined the impact of organization and team level structure constructs (organizational culture, team complexity, and team leadership) on hospice interdisciplinary team processes and subsequent influence on perceived team effectiveness. The relationships among perceived team effectiveness, team task satisfaction, and family satisfaction with hospice care were also examined.The sample consisted of 41 hospice interdisciplinary teams drawn from two hospice organizations in a southwestern city of the United States. Participants included 410 interdisciplinary team members and 32 hospice team leaders. Measures used in this research were adapted from instruments previously used in non-hospice settings. Data were collected through self-report surveys. Psychometric properties of all instruments were performed at the individual and group level. Psychometric properties of all but three scales (Hospice Organizational Culture: Group Culture, Hierarchical Culture, and Developmental Culture) exhibited reliability and evidence of validity as group measures.Four hypothesized relationships were supported, and six nonhypothesized relationships were significant in the model. All team processes except conflict management had positive direct effects on perceived team effectiveness. Perceived team effectiveness had a positive direct effect on team task satisfaction, and team task satisfaction was positively correlated with family satisfaction with hospice care in a limited sample. The proposed structural factors (hospice organizational culture, team complexity, and team leadership) did not impact hospice interdisciplinary team processes or team effectiveness. Approximately sixty-five percent of the variance in team effectiveness was explained by team hospice experience and team processes (leadership, communication, and coordination). Nearly fifty percent of variance in team task satisfaction was explained by the processes used for conflict management and perceived team effectiveness.Relationships identified in this research are viewed as preliminary. Future research should modify and re-examine model relationships with a larger sample drawn from diverse hospice organizations. In addition, structural variables influencing the hospice interdisciplinary team need to be re-examined for appropriateness and conceptual relevance. However, this study provided a foundation for understanding hospice interdisciplinary team processes and the influence of these processes on team and family satisfaction.
25

Linear and Nonlinear Optical Study of Multilayer Ferroelectric Polymer Systems

Jones, Jennifer Ann 18 March 2015 (has links)
Multilayer polymer systems are a focus of increasing research effort motivated by the possibility to realize compact and flexible energy storage and energy harvesting devices. However, the performance and stability of these polymer systems are highly dependent on temperature. In this study the structure of monolayer ferroelectric polyvinylidene fluoride (PVDF) thin films and the relaxation dynamics as a function of temperature are characterized using XRD, FTIR and second harmonic generation (SHG). Multilayered ferroelectric polyvinylidene fluoride (PVDF) systems are fabricated using enabling technology in co-extrusion for increased energy storage and energy harvesting efficiency as well as increased stability at elevated temperatures. To understand the physics of why these multilayered systems perform better than single layer PVDF characterization techniques using second harmonic generation (SHG), electric field induced second harmonic (EFISH) and Raman laser spectroscopy are developed. Results show that the combination of Raman and SHG is a very sensitive, non-destructive and versatile technique that can be used to study the ferroelectric and structural properties of these systems. The addition of the EFISH technique allows the interrogation of structural and dielectric properties within individual layers and at the interfaces.
26

Challenging Conventional Approaches to Energy Storage: Direct Integration of Energy Storage into Solar Cells, the Use of Scrap Metals to Build Batteries, and the Development of Multifunctional Structural Energy Storage Composites

Westover, Andrew Scott 22 November 2016 (has links)
Since the development of batteries by Edison and Volta, energy storage has become an integral part of our technology. As the energy storage devices we manufacture, research and develop new energy storage systems has been standardized. This dissertation present three alternative approaches to developing energy storage devices which could completely change the paradigm by which we manufacture and use energy storage. First, I present my work in developing energy storage devices that can be directly integrated into the back of Silicon photovoltaics. This includes initial proof of concept of direct integration of porous Si supercapacitors followed by investigations into high rate faradaic chemical reactions with porous Si and coated porous Si. These faradaic reactions have the possibility of higher energy storage and power matching the performance of silicon photovoltaics. Second, I demonstrate the feasibility of using scrap metals to make high rate batteries that can be paired with photovoltaics by anodizing scrap steel and brass using simple manufacturing methods compatible with do it yourself manufacturing. Third, I will present my work in developing multifunctional structural supercapacitor composites. I demonstrate the ability to measure in-situ the electrochemical response of solid state electrolyte and supercapacitors. I follow this initial work up with the realization of a structural supercapacitor with the mechanical performance approaching that of commercial structural composites and energy storage performance approaching commercial supercapacitors.
27

Controlling Nanomaterial Assembly to Improve Material Performance in Energy Storage Electrodes

Oakes, Landon Joseph 12 September 2016 (has links)
Nanomaterials have enabled significant breakthroughs in energy storage capabilities. In particular, the use of nanoscale components in lithium-sulfur and lithium-oxygen batteries have generated energy densities 2-3x greater than todayâs lithium-ion batteries. However, a major roadblock to commercially viable applications of nanomaterials is the ability to cost-effectively manufacture electrode-scale films while still maintaining precise control over the nanoscale morphology. In this regard, electrophoretic deposition (EPD) provides a promising tool for large-scale manufacture of nanomaterial systems using conventional liquid processing techniques. During EPD, the use of electrochemical equilibria to stabilize suspensions of nanomaterials eliminates the need for additives and provides a mechanism to control the placement of individual nanostructures on both 2D and 3D substrates through the application of an electric field. The viability of this process for large scale manufacture is demonstrated by integrating EPD electrode fabrication with nanomaterial synthesis processes on a benchtop roll-to-roll platform. Using this approach, lithium-sulfur and lithium-oxygen electrodes are fabricated that demonstrate enhanced mass-specific performance compared with identical material compositions assembled using conventional techniques. For lithium-oxygen batteries, the role that catalyst assembly plays in dictating the performance of the battery is elucidated and improved through EPD. Likewise, for lithium-sulfur batteries, the coating of an elemental sulfur layer is engineered in conjunction with an all-carbon EPD assembled electrode to produce one of highest capacity and most reversible lithium-sulfur cathodes ever reported. Overall, this thesis demonstrates the role of nanomaterial assembly in determining the energy storage performance of electrode-scale films and presents a method to control this assembly that is amenable to large-scale manufacture.
28

Mapping the Electromagnetic Near Field of Gold Nanoparticles in Poly(methyl) Methacrylate

Engerer, Kristin Jean 28 November 2016 (has links)
As electronic and optical devices shrink to the nanoscale, accurate methods for characterizing electromagnetic fields generated by sub-wavelength structures become increasingly important. Absorption in poly(methyl methacrylate) (PMMA) via 4th harmonic generation in metallic nanostructures is a way to characterize complex resonance modes. When exposed with a femptosecond Ti:sapphire oscillator, the damaged PMMA surrounding the nanoparticles can be imaged with an scanning electron microscope, creating an electric near-field intensity profile. This occurs without absorbing the fundamental frequency, and provides an accurate visualization of the resonant fields. Localized surface plasmonic near-fields generated by metallic nanorods have been mapped previously with this technique. In this document, nanorods and bowtie antennas are fabricated and the electric near-field intensity imaged with PMMA mapping. We then analyzed this data to determine more about the technique and about what drives the resonance of plasmonic nanoantennas.
29

The theory and application of bipolar transistors as displacement damage sensors

Tonigan, Andrew Michael 27 March 2017 (has links)
An important aspect of engineering systems for use in extreme environments is understanding the performance of electronic components in radiation environments (e.g., space environments, nuclear reactors, particle accelerators). To accomplish this, experimental and computational modeling approaches are used to understand physical mechanisms that lead to system level failures. When experimentally investigating displacement damage, a common radiation effect, the most important parameter to measure is the particle fluence. An approach that offers benefits over traditional measurement techniques uses the degradation of current gain in silicon bipolar junction transistors as a direct metric for displacement damage in silicon. This thesis covers the bipolar device physics and particle/crystal interactions necessary to understand how displacement damage leads to gain degradation and describes how bipolar devices can be applied as displacement damage sensors to measure particle fluence. The use of bipolar junction transistors as displacement damage sensors in neutron irradiations is demonstrated at lower fluences than previously achieved and first-of-a-kind displacement damage sensor measurements for proton irradiations are provided. The non-ionizing energy loss (NIEL) of each particle is shown to adequately correlate the two particle types, neutrons and protons, across five orders of magnitude of particle fluence using three bipolar junction transistors (2N1486, 2N2484, 2N2222).
30

The Phase Dependent Optoelectronic Properties of Ternary I-III-VI2 Semiconductor Nanocrystals and Their Synthesis

Leach, Alice Dorinda Penrice 31 March 2017 (has links)
Colloidal semiconductor nanocrystals have become one of the most versatile systems for studying the fundamental properties of nanoscale materials and their applications. The ternary I-III-VI2 semiconductors hold particular promise for applications due to their flexible stoichiometry, low toxicity constituent elements, and range of desirable band gap energies (0.5 â 3.5 eV). Furthermore, I-III-VI2 nanocrystals can be isolated in metastable, anisotropic crystal structures not seen in the bulk. This structural anisotropy can be exploited to produce nanostructures with asymmetric morphology and electronic structure, which can enhance their performance in optoelectronic applications. In this dissertation, metastable, anisotropic crystal structures of I-III-VI2 materials are synthesized and their optoelectronic properties are investigated. CuInS2 has been widely explored for use in solar energy capture due to its band gap near the visible spectral region. Here, a direct synthesis to luminescent CuInS2 nanocrystals with the anisotropic wurtzite phase is developed and the mechanism of their formation is identified. A combined experimental and theoretical approach is then used to identify the radiative defect responsible for the luminescence observed. Furthermore, hybrid wurtzite CuInS2-Pt nanocrystals are prepared and their photoelectrical properties characterized to determine the efficacy of this system in photocatalytic applications. The knowledge obtained from the CuInS2 system is then applied to additional I-III-VI2 materials, CuFeS2 and AgFeS2. Wurtzite CuFeS2 is prepared using three distinct synthetic routes and the resultant nanocrystals are compared to each other and the In-containing analogues. Anisotropic, orthorhombic nanocrystals of AgFeS2 are also synthesized and characterized for the first time. The presence of Fe in both these systems leads to the observation of broad multimodal absorbance features at low energy, which can be utilized in thermoelectric and photothermal applications. Experimental measurements and density functional theory calculations indicate that this unique absorbance originates from changes in the composition of the nanocrystals.

Page generated in 0.0799 seconds