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  • 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

Identifying the Role of Policy Networks in the Implementation of Habitat Conservation Plans

January 2015 (has links)
abstract: Conflict over management of natural resources may intensify as population growth, development, and climate change stress natural systems. In this dissertation, the role of policy networks implementing Habitat Conservation Plans (HCPs) is examined. As explored here, policy networks are groups that come together to develop and implement terms of HCPs. HCPs are necessary for private landowners to receive Incidental Take Permits (ITPs) from the U.S. Fish and Wildlife Service (USFWS) if approved development activities may result in take of threatened or endangered species. ITPs may last up to 100 years or more and be issued to individual or multiple landowners to accomplish development and habitat conservation goals within a region. Theoretical factors in the implementation and policy network literatures relevant to successful implementation of environmental agreements are reviewed and used to examine HCP implementation. Phase I uses the USFWS Environmental Conservation Online System (ECOS) database to identify characteristics of policy networks formed to implement HCPs within the State of California, and how those networks changed since the creation of HCPs in 1982 by amendment of the 1973 Endangered Species Act. Phase II presents a single, complex, multiple-party HCP case selected from Phase I to examine the policy network formed, the role of actors in this network, and network successes and implementation barriers. This research builds upon the implementation literature by demonstrating that implementation occurs in stages, not all of which are sequential, and that how implementation processes are structured and executed has a direct impact on perceptions of success. It builds upon the policy network literature by demonstrating ways that participation by non-agency actors can enhance implementation; complex problems may better achieve conflicting goals by creating organizational structures made up of local, state, federal and non-governmental entities to better manage changing political, financial, and social conditions; if participants believe the transaction costs of maintaining a network outweigh the benefits, ongoing support may decline; what one perceives as success largely depends upon their role (or lack of a role) within the policy network; and conflict management processes perceived as fair and equitable significantly contribute to perceptions of policy effectiveness. / Dissertation/Thesis / Doctoral Dissertation Public Administration 2015
22

Modélisation du maclage à l’échelle atomique dans les métaux hexagonaux : germination et migration de disconnections dans le zirconium, le titane et le magnésium / Atomic scale modeling of twinning in zirconium and titanium

MacKain, Olivier 18 July 2017 (has links)
L'objectif de la thèse est d'identifier et de quantifier les paramètres régissant l'épaississement des macles dans trois métaux hexagonaux (Zr, Ti, Mg). Le mécanisme que nous étudions est le glissement de dislocations d'interfaces, i.e. les disconnections, le long des joints de macles parfaits. Nous nous intéressons alors à la germination des disconnections avant de nous concentrer sur leur migration.Une première étude en potentiel empirique permet de valider un couplage original avec la théorieélastique afin d'extraire des simulations atomiques l'énergie de cœur des disconnections. Cette méthode permet de partitionner l'énergie entre une contribution de cœur, intrinsèque à la disconnection et une partie élastique qui dépend de l'environnement de la disconnection. Cette partition faite, nous modélisons alors l'énergie de formation de dipôles de disconnections isolés, pour chacun des différents joints de macles. Cette modélisation nous permet alors de sélectionner les dipôles de disconnections les plus pertinents que nous étudions par la méthode abinitio.Nous modélisons ensuite la migration des disconnections le long des joints de macles parfaits.Pour cela, nous montrons via l'utilisation de la méthode Nudged Elastic Band, que l'énergie demigration est d'un ordre de grandeur inférieur à l'énergie de formation. Ainsi, l'énergie de formation des dipôles de disconnections apparait comme prédominant dans la croissance des macles / The aim of this thesis is to identify and quantify the parameters of importance when dealing with twin thickening in three hcp metals (Zr, Ti, Mg). The mechanism we study is the glide of twinning dislocations, i. e. the disconnection, along the perfect twin boundaries. We first focus on the nucleation of disconnection before addressing their migration. A study using an EAM potential allows us to validate an original coupling between our atomistic simulations and linear elasticity in order to extract the core energy of disconnection.We then show how this coupling permits to divide the formation energy in two terms: the core contribution, intrinsec to the disconnections, and an elastic one, which depends on the disconnection's environment. Thanks to this partition, we model the formation of isolated disconnection that may appear along the different twin planes. We select the dipoles of lowest formation energies in order to perform ab initio calculations and compare the behavior observed the three different metals. We then model the migration of disconnections along the perfect twin planes. To do so, we use the Nudged Elastic Band method, and find out that the migration energy of disconnections is one order of magnitude lower than their formation energies. We therefor conclude that the disconnection nucleation is the rate limiting factor to explain twin thickening thanks to the creation and motion of disconnection
23

Characterisation of the deformation mechanisms in HCP metals by combined use of X-ray imaging and diffraction techniques

Nervo, Laura January 2015 (has links)
We envisage a fundamental study of the physical mechanisms (dislocation slip versus deformation twinning) involved in plastic deformation of hexagonal close-packed (HCP) metals like titanium and magnesium. A novel combination of X-ray imaging and diffraction techniques, termed X-ray diffraction contrast tomography (DCT), will be used to investigate details of the deformation process in the bulk of polycrystalline specimen. DCT provides access to the position, 3D shape, (average) orientation and elastic strain tensor of grains in polycrystalline sample volumes containing up to 1000 grains and more. Ultimately, an extension of the X-ray DCT technique is associated with a section topography methodology on the same instrument. This combination enables the measurement of local orientation and elastic strain tensors inside selected bulk grains. A very preliminary study of this approach is carried out on a magnesium alloy, underlying the current limitations and possible improvements of such approach. In this thesis, the data acquisition and analysis procedures required for this type of combined characterisation approach have been developed. The work is supported by the use of neutron diffraction, for an in-situ loading experiments, and two-dimensional electron backscatter diffraction (EBSD), for the initial microstructure of the materials and cross-validation of the results obtained with the X-ray DCT technique.
24

Predicting Polymorphic Phase Stability in Multilayered Thin Films

Thompson, Gregory B. 19 March 2003 (has links)
No description available.
25

MOLECULAR DYNAMICS SIMULATION STUDY OF SOLID-LIQUID INTERFACE PROPERTIES OF HCP MAGNESIUM

Bai, Yunfei 10 1900 (has links)
<p>The structural and thermodynamic properties of a crystal-melt interface in</p> <p>elemental magnesium have been investigated using molecular dynamics (MD)</p> <p>simulations with an embedded atom method description of the interatomic potential.</p> <p>Three low index interfacial orientations, (0001), (1101) and (1120), have been studied.</p> <p>From fine-grained atomic density profiles, the structural interfacial widths show obvious anisotropy and the variation of interatomic planar spacing as a function of distance through the crystal-melt boundary is established. Mainly from the coarse-grained density profiles, the effective 10-90 width of the interface region, defined as the intrinsic width, in each orientation has been determined. In addition, the interfacial stresses are obtained from an integration of the interfacial stress profiles and the results show significant anisotropy, which is possibly related to the anisotropy of occupation fraction profiles. Finally, from a determination of the excess energy and interfacial stress of the solid-liquid interface and from previous published results for the interfacial free energy at the melting point, the Gibbs-Cahn integration is employed to derive an estimation of the temperature dependence of the interfacial free energy at non-equilibrium temperatures. All of the crystal-melt interfacial properties for magnesium are compared with simulation data from other elemental metals and alloys, as well as from other model systems such as Lennard- Jones and hard spheres.</p> / Master of Applied Science (MASc)
26

Communication dynamics in producing effective patient care : a case study at Stanger Hospital’s diabetes clinic in Kwazulu-Natal, South Africa

Moola, Sabihah 03 1900 (has links)
Text in English / Interactive health communication between the health-care professional (HCP) and patient relationship for diabetes health-care positively contributes to patient-centred care. Hence individual patient concerns are addressed and catered for in the medical system. The purpose of this study was to analyse in-depth how HCP-patient relationships and HCP-HCP teamwork dynamics positively contribute to effective diabetes patient care and treatment adherence. Different health communication models and theories were reviewed and a conceptual framework was developed from the literature. A qualitative case study approach was used to collect data at Stanger Hospital’s diabetes clinic. Data was collected using three different methods, namely in-depth interviews with HCPs and patients individually, observations conducted at the clinic analysing both the HCPs and patients, and finally, documentation that emerged as a third data collection method where patient files and diabetes educational material were analysed at the clinic. Triangulation by means of the three methods ensured that reliable, valid and credible data was collected in the field. Diabetes health-care and treatment management are affected by the social context/social system which includes family and culture. These social factors are acknowledged as core in the literature. However, a single comprehensive health communication model did not exist solely in this regard. The data indicated that at the Stanger Hospital’s diabetes clinic, patient-centred (individual tailor-made treatment plans) care was only implemented after patients had defaulted treatment for reasons linked to their social circumstances. The findings of the study indicate that teamwork was favoured in the HCP-HCP relationship at the diabetes clinic, and that this made a positive contribution to effective diabetes patient care. HCPs were overburdened at the clinic since patient numbers were high and there were staff shortages. The patients’ empirical data indicated that interactive communication positively contributed to their medical concerns being catered for at the diabetes clinic, but this tended to occur only after non-adherence. Patients required care and support from HCPs in order to learn to accept diabetes and manage their illness. / Sociology / D. Litt. et Phil. (Sociology)
27

The instructional design of a training program for audiometricians

De Clercq, Hendrika 25 July 2012 (has links)
This study focused on designing a training programme for audiometricians, using the principles of instructional design. Instructional design is the continuing, systematic development of instructional specifications, utilizing researched strategies and principles to create detailed outcomes for the development, implementation, evaluation and maintenance of training programmes. An audiometrician is defined by SANS (10083:2004), as a person registered with the Health Professions Council of South Africa as an audiometrician, hearing aid acoustician or someone trained in audiometry. Audiometricians are adult learners. Therefore, in addition to instructional design principles, the principles of adult learning were also incorporated in the training programme. The successful training of audiometricians may ensure that noise induced hearing loss is significantly reduced when audiometric monitoring is appropriately implemented as part of a hearing conservation programme. Training for audiometricians is critical in this process as incorrect audiometric monitoring may negatively influence the outcomes of a hearing conservation programme. This study followed a descriptive research design where the results were described in a quantitative manner. Data was collected by means of electronically mailed questionnaires. All participants were practicing audiometricians at the time of the study and were registered with the South African Society for Occupational Health Nursing. All participants had an audiometric certificate as qualification. For the analysis of data, 181 completed questionnaires were used. The results were analyzed and described in terms of the respondents’ own experience regarding audiometry; their opinions regarding the topics they have been taught in audiometry; the duration of their own training programmes and their opinions regarding a future training programme for audiometricians. Based on the results of the above analysis, the instructional design programme for audiometricians was developed. The obtained results were used to determine what the topics, content, duration, learning outcomes and learner evaluation methods should be in the development of a training programme for audiometricians. This research study developed a training programme for audiometricians in order to ensure that all future audiometricians have the necessary knowledge to perform comprehensive hearing evaluations, interpret audiometric findings and thereby assist in reducing noise induced hearing loss in the industrial sector through hearing conservation programmes. AFRIKAANS : Hierdie studie is toegespits op die ontwerp van ‘n onderrigprogram vir oudiometriste waarin die beginsels van onderrigontwerp toegepas is. Onderrigontwerp behels die deurlopende en stelselmatige ontwikkeling van onderrigspesifikasies deur gebruik te maak van nagevorsde strategieë en beginsels om gedetailleerde uitkomste vir die ontwikkeing, evaluering en onderhoud van opleidingsprogramme daar te stel. ‘n Oudiometris word gedefinieer deur wetgewing (SANS 10083:2004) as ‘n person wat geregistreer is by die Health Professions Council of South Africa as ‘n oudiometris, gehoorapparaat akoestikus of iemand wat opgelei is in oudiometrie. Oudiometriste is volwasse leerders. Om hierdie rede is nie net die beginsels van onderrigontwerp nie, maar ook die beginsels van volwasse leer in die onderrigprogram geïnkorporeer. Suksesvolle onderrig van oudiometriste kan verseker dat die voorkoms van geraas-geïnduseerde gehoorverlies verminder, mits oudiometriese monitering toepaslik as deel van ‘n program vir gehoorkonservering geïntegreer word. Opleiding vir oudiometriste is krities belangrik in hierdie proses want indien oudiometriese monitering verkeerd gedoen word, kan dit die gehoorkonserveringsprogram in totaliteit negatief beïnvloed. ‘n Beskrywende navorsingsontwerp is in hierdie studie gebruik en die resultate is kwantitatief beskryf. Data is deur middel van vraelyste wat elektronies versend is, versamel. Al die deelnemers was ten tye van die studie praktiserende oudiometriste wat by die South African Society for Occupational Health Nursing geregistreer was. Elkeen was in besit van ‘n oudiometriese sertifikaat as kwalfikasie. Vir data-ontleding is 181 voltooide vraelyste gebruik. Die data was geanaliseer en beskryf in terme van die respondente se eie ervaring ten opsigte van oudiometrie; hul mening omtrent die temas wat by hul opleiding ingesluit was; die duur van hul opleidingsprogramme en hul idees omtrent ‘n toekomstige opleidingsprogram vir oudiometriste. Die onderrigontwerp-program is op grond van die resultate van bognoemde analise ontwikkel. Die resultate wat verkry is, is gebruik om die temas, inhoud, duur, leeruitkomste en evalueringsmetodes in die ontwikkeling van ‘n opleidingsprogram vir oudiometriste te bepaal. Hierdie studie is gerig op die ontwikkeling van ‘n opleidingsprogram vir oudiometriste met die doel om te verseker dat hulle oor die nodige kennis beskik om omvattende gehoorevaluerings uit te voer, om oudiometriese bevindinge te interpreteer en daardeur, in gesondheidssorgprogramme, by te dra tot die vermindering van geraas-geïnduseerde gehoorverlies in die industriële sektor Copyright / Dissertation (MCommunication Pathology)--University of Pretoria, 2012. / Speech-Language Pathology and Audiology / unrestricted
28

Characterization and Modeling of Creep Mechanisms in Zircaloy-4

Morrow, Benjamin M. 02 September 2011 (has links)
No description available.

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