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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

Facets and Sharp Edges in Metal Nanostructures for Plasmonics and Electrocatalysis

Nesbitt, Nathan Taylor January 2018 (has links)
Thesis advisor: Michael J. Naughton / The nanoscale morphology of metals can enable special functionality in plasmonic and electrochemical devices, with applications in energy conversion and storage, sensors, and computers. In particular, sharp edges on metal nano and microstructures are understood to affect the density of electrons on the metal surface. The associated concentration of electric field can concentrate surface plasmon polaritons (SPPs) and enable waveguiding of the SPPs, as we show in this thesis for sharp ridges along aluminum nanowires. Also important is the presence of facets on the metal structures, which determines the orbitals that electrons occupy on the metal surface. Changes in both the electron density and orbitals can affect the binding of molecules to the metal, which can improve reaction kinetics in catalysis. We demonstrate this on gold dendrite and plate electrocatalysts for CO2 electrolysis. Regarding metal nanostructure fabrication, electrochemical deposition and corrosion have demonstrated promising control over the morphology, including the topography, crystallinity, grain boundaries, and crystal faceting. This is important, because existing methods for metal nanostructure fabrication can only produce a circumscribed assortment of morphologies. In contrast, semiconductors and insulators have many new deposition techniques that produce a wide range of controlled morphologies. Of further appeal, electrochemical techniques are solution-based and typically operate at room temperature and pressure, allowing facile scale-up to industrial production. Here we demonstrate and discuss the mechanisms of two new techniques, which produce the aluminum nanowires and gold dendrites and plates discussed above. / Thesis (PhD) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.
22

Geology of the Sharp Mountain Area, Southern Part of the Bear River Range, Utah

Hafen, Preston L. 01 May 1961 (has links)
The Sharp Mountain area is situated in the southern part of the Bear River Range in Utah. The geology of the Bear River Range to the north of this area, in Utah and Idaho, has been mapped; however, prior to this study little was known about the Sharp Mountain area. The purpose of this investigation are as follows: (1) to map and describe the geology of the area, and (2) to relate the stratigraphic and structural features of the Sharp Mountain area to those of the surrounding region.
23

Structural Geology of Eastern Part of James Peak Quadrangle and Western Part of Sharp Mountain Quadrangle, Utah

Rauzi, Steven L. 01 May 1979 (has links)
A detailed study was made of the James Peak-Sharp Mountain area, in the southern part of the Bear River Range, Utah. The mapped area is located in north-central Utah between lat. 41°22'30" N. and lat. 41°30' N. and long. 111°42'30" W. and long. 111°46' W. It measures about 3.8 miles in the east-west direction and 8.7 miles in the north-south direction. The area is centered about 22 miles south-southeast of Logan, Utah. Stratigraphic units of late Precambrian to Mississippian age underlie the mapped area. The Precambrian units include the Mutual and Browns Hole Formations. The Brigham, Langston, Ute, Blacksmith, Bloomington, Nounan, and St. Charles Formations make up a complete Cambrian section. The Ordovician Garden City and Swan Peak Formations, the Ordovician-Silurian Laketown Formation, the Devonian Water Canyon and Hyrum Formations, and the Mississippian Lodgepole and Humbug Formations overlie the St. Charles in normal succession. The oldest unit the Precambrian Mutual Formation, crops out in the southern part of the area on the eastern side of James Peak. The rock units are progressively younger toward the northern part of the area. Mesozoic rocks are not present. The Salt Lake Formation of Tertiary age directly overlies the Paleozoic rocks. The main structural feature of the area is an asymmetrical north-south-trending anticline. The eastern flank dips more steeply than the western flank. The anticline plunges gently north and dies out southward. This anticline is one of a series of asymmetrical anticlines, all steeper on the east than on the west, that includes the Strawberry Valley anticline to the east and the anticline exposed in upper Wolf Creek Canyon to the west. The late Precambrian and early Paleozoic formations, which dip northeast on the eastern flank of James Peak, make up the northeastern flank of the anticline exposed in upper Wolf Creek Canyon. The early Paleozoic to Devonian formations that form Sharp Mountain and dip gently west make up the western flank of the Strawberry Valley anticline. Low-angle thrust faults have disrupted the Precambrian and Paleozoic formations on the eastern and southeastern flanks of James Peak. Displacement on the thrust fault north of upper Wellsville Creek is about 2,000 feet. Movement was generally from the west. Normal faults have disrupted the Paleozoic and Tertiary formations along the eastern margin of Cache Valley and the Paleozoic formations east of McKenzie Mountain. Displacement is indeterminate along the eastern margin of Cache Valley. Maximum displacement, east of McKenzie Mountain, is about 1,750 feet. The normal faults truncate the folds and thrust faults. The folds and thrust faults were formed during the Laramide orogeny. The normal faults were formed during Basin and Range normal faulting. Basin and Range normal faulting is active at the present time.
24

Sharp object fatalities in East London: A descriptive study.

Dixon, Kurt. January 2009 (has links)
<p>Data from the National Injury Mortality Surveillance System (NIMSS) show that homicide is the major cause of death with firearms and sharp objects as the main external causes of death in South Africa. The current study is a descriptive study, describing the epidemiology of sharp object fatalities in the city of East London (also known as Buffalo City) in South Africa. It is a secondary data analysis of mortuary data collected by morticians trained in data collection methods according to World Health Organisation standards. This descriptive study aimed to develop the profile of sharp object fatalities in East London. Most of the findings were consistent with other literature on sharp object violence/homicide and on homicide in general using rates per population denominator data. It also combined variables to arrive at more complex descriptions. The following risk factors were identified: male, between the ages 30-34, being from a disadvantaged population group, alcohol consumption, weekend, between the times 20h00 and 23h59 and if we discount the place of death, &lsquo / unknown&rsquo / then the greatest percentage of deaths occurred in a private house. The results were interpreted within an ecological and contextual theoretical framework to hypothesize possible etiological factors. The conclusion was that there were multiple variables which all interact and influence one another across all ecological levels and as other studies have recommended, this study too also recommends that more work is needed in order to identify the multiple pathways leading to fatalities, perhaps by way of multivariate studies as well as qualitative studies with perpetrators of sharp object fatalities.</p>
25

Sharp object fatalities in East London: A descriptive study.

Dixon, Kurt. January 2009 (has links)
<p>Data from the National Injury Mortality Surveillance System (NIMSS) show that homicide is the major cause of death with firearms and sharp objects as the main external causes of death in South Africa. The current study is a descriptive study, describing the epidemiology of sharp object fatalities in the city of East London (also known as Buffalo City) in South Africa. It is a secondary data analysis of mortuary data collected by morticians trained in data collection methods according to World Health Organisation standards. This descriptive study aimed to develop the profile of sharp object fatalities in East London. Most of the findings were consistent with other literature on sharp object violence/homicide and on homicide in general using rates per population denominator data. It also combined variables to arrive at more complex descriptions. The following risk factors were identified: male, between the ages 30-34, being from a disadvantaged population group, alcohol consumption, weekend, between the times 20h00 and 23h59 and if we discount the place of death, &lsquo / unknown&rsquo / then the greatest percentage of deaths occurred in a private house. The results were interpreted within an ecological and contextual theoretical framework to hypothesize possible etiological factors. The conclusion was that there were multiple variables which all interact and influence one another across all ecological levels and as other studies have recommended, this study too also recommends that more work is needed in order to identify the multiple pathways leading to fatalities, perhaps by way of multivariate studies as well as qualitative studies with perpetrators of sharp object fatalities.</p>
26

Entwicklung eines Einsatzabwicklungssystems für Feuerwehren EASy

Tröndle, Stefan Michael. January 2004 (has links)
Konstanz, FH, Diplomarb., 2003.
27

Influence of perforant path synaptic excitation on the initiation of hippocampal sharp-wave ripple activity in vitro

Kanak, Daniel James 01 December 2013 (has links)
Sharp-wave ripples (SWR) generated in the CA3 subregion of the hippocampus (HC) during rest and sleep appear to coordinate memory consolidation to the neocortex (NC) by (1) reactivating small subsets of neurons (i.e. cell-assemblies) that encode recent waking experience and (2) propagating this information through the hippocampal formation. Although CA3 self-organizes SWRs in the absence of extrinsic inputs, cortical input to the HC conveyed by perforant path (PP) may influence SWR initiation nevertheless. Still, direct evidence that PP synaptic excitation can elicit SWRs is lacking, and it is unclear how this influence might compete or interact with self-organizing mechanisms. This dissertation tested the hypothesis that CA3's SWR pattern generator would self-organize its activity in the absence of PP input, but readily entrain to such input when present. Spontaneous SWRs (sSWR) occurred in slices prepared from the ventral portion of the mouse HC. Low-intensity electrical stimulation of PP afferents evoked short-latency field EPSPs in CA3 that were often followed by precisely timed evoked SWRs (eSWR). The network and single-cell characteristics of sSWRs and eSWRs were indistinguishable, indicative of a common patter generator. PP stimuli that followed sSWRs too closely usually failed to elicit eSWRs. Using a custom MATLAB/Simulink application to control PP stimulus timing during the ~250 ms sSWR refractory period revealed a statistically significant effect of stimulus delay (25, 50, 100, and 200 ms) on eSWR incidence, reaching a value of 0.72 (95% CI = [0.61, 0.81]) 200 ms after sSWR onset. In contrast, sSWR incidence at this time was much lower (95% CI = [0.015, 0.049]). Lesions targeting the direct PP input to CA3 substantially reduced eSWR incidence. In intact slices, eSWRs were readily evoked by stimulating the medial entorhinal cortex (MEC). In summary, PP input to CA3 from the MEC can initiate SWRs at times when self-organizing mechanisms generally cannot. Assuming sSWRs convey information to the NC, the ensuing refractory period might provide an opportunity for cortical feedback to reinforce the recently engaged cell-assembly. In the absence of such feedback, CA3 could revert to its default mode of self-organized replay.
28

Implementación del Protocolo Modbus Sobre una Tarjeta de Desarrollo para su Uso Sobre una Red GSM con Enfoque en Telemetría

Oyarce Miño, Andrés Reynaldo January 2009 (has links)
El objetivo principal del presente trabajo de título es el diseño, desarrollo e implementación de un prototipo formado por módulos llamado iNodos, que serán la base de un sistema de telemetría. Esto es, obtener los datos a distancia por medio de varios iNodos, para luego enviarlos a un centro donde se almacene la información. Debido a la creciente demanda de este tipo de soluciones, se hace necesaria la creación de un sistema capaz de realizar estas mediciones de manera remota. Es así como la amplia cobertura de las redes GSM, en conjunto con soluciones inalámbricas de última milla han resuelto el problema de acceso. La principal problemática radica en el costoso cableado requerido por los aparatos electrónicos, así como la dificultad para acceder a ciertos terrenos, muchas veces inaccesibles. Además considerando que los puntos de medición se encuentran en un radio menor de 100 mt, se propone una estructura que considera el uso de una red de módulos XBee interconectados mediante el protocolo de comunicaciones Modbus a un módulo Maestro que a su vez se comunica utilizando la red GSM como un nodo centralizado para enviar los datos.. Este permite una completa y documentada forma de transmitir datos, utilizando protocolos confiables. Para administrar la red de telemetría, se creó un programa en C#, el cual permite obtener los datos provenientes de sensores y guardarlos en una Base de Datos para su posterior proceso. Este programa, se comunica entre las distintas redes de telemetría existentes, con sólo un ID, nombre y clave. El prototipo no sólo permite eliminar el cableado en este tipo de redes, sino que además logra obtener datos de manera remota y confiable, sin la necesidad de estar físicamente en el lugar en donde se toman los datos. Además está hecho de tal forma, que es totalmente escalable, ya que se realizó en base a módulos que cumplen una determinada función. Por lo tanto cada uno de ellos se puede cambiar perfectamente sin ningún inconveniente. Se logró crear un prototipo confiable en cuanto a la transferencia de datos, que permite la medición a distancia con sólo ingresar un simple comando. Para trabajo futuro se recomienda mejorar la interfaz de usuario del programa; permitir agregar sub-nodos y sub-redes para agrandar más el alcance y el número de sensores; y permitir crear una base de datos con los datos, para que la medición se realice de manera programada.
29

Desarrollo de una Aplicación Móvil para la Administración de Avances sobre Planos Arquitectónicos

Dujovne Weinberger, Nicolás Eduardo January 2007 (has links)
No description available.
30

Nonviolence as impure praxis : reconstructing the concept with Aldo Capitini

Baldoli, Roberto January 2015 (has links)
This thesis aims to ‘reconstruct’ the concept of nonviolence, offering a new unifying and pluralistic definition, which rejects recent worrying uses of the term, and is able to deal with the crisis of democracy and the construction of a post-secular society. Currently nonviolence is split in two between principled and pragmatic nonviolence. This division has been successful, but it is now a problem: it divides means and ends, politics and morality, religion and politics. In order to find a way out we will turn to the Italian philosopher Aldo Capitini. He interpreted nonviolence as a tension, a praxis of liberation from the chains of reality and openness to the existent. This approach includes a pragmatic dimension, which is a logic reinterpreting current practices and inventing new ones to build up via facti a new society (omnicracy); and a principled dimension, which is a craft of integrating reality with values, reaching its peak in the connection with everybody in an action of value (compresence). This approach offers actions of protest-to-project to overcome the division between means and ends; a political approach between ‘realism and serenity’ to overcome the division between politics and morality; an open religion which can work at the centre of society and politics. Finally, we will extend Capitini’s reflection claiming that nonviolence as praxis is a non-systematic revolutionary approach aiming at freedom and plurality. We will add that this praxis is impure, because made of less than perfect actions performed in a very imperfect environment by imperfect human beings. Reconceiving nonviolence as impure praxis will allow us to reunite principled and pragmatic nonviolence, reinterpreting the former as actualisation of a public principle and the latter as a phronesis. This interpretation will offer an interesting form of transformative realism, which enriches via facti any democratic order with life, and show the way to overcome the secular divisions towards a post-secular society centred on the Assisi presumption.

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