• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 80
  • 27
  • 15
  • 8
  • 8
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 196
  • 33
  • 22
  • 13
  • 11
  • 11
  • 10
  • 10
  • 9
  • 9
  • 8
  • 8
  • 8
  • 8
  • 7
  • 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.
91

Force and Energy Measurement of Bubble-Particle Detachment

Schimann, Hubert C. R. 15 June 2004 (has links)
Possibilities for increasing the upper limit of floatable particle sizs in the froth flotation process have been examined since the early beginnings of mineral flotation. The economic implications of such an incresae are far ranging; from decreased grinding costs and increased recoveries to simplified flow-sheet design and increased throughput, all leading to increased revenue. Bubble-particle detachment has been studied to better understand the factors influencing the strength of attachment and the energies involved. Direct measurements of bubble particle detachment were performed using a hanging balance apparatus (KSV Sigma 70 tensiometer) and using a submerged hydrophobic plate in water. Three experiments were used; direct force measurement of bubble-particle detachment, detachment force and energy of a bubble from a submerged hydrophobic plate, and detachment force and energy of a cetyltrimethylammonium bromide coated silica sphere from a flat bubble. Octadecyltrichlorosilane was used as a hydrophobic coating in the first two experimental methods. These experiments were recorded with a CCD camera to identify the detachment processes involved. Energies for both methods were calculated and divided into the two main steps of the detachment process: Three-Phase-Contact pinning and three phase contact line sliding. The first step represents the energy barrier which must be overcome before detachment can begin. It is directly related to contact angle hysteresis. Detachment occurs during the second step, where the solid-vapor interface is replaced by solid-liquid and liquid-vapor. This step corresponds to the work of adhesion. The effects of surface tension, contact angle and hysteresis were well demonstrated with the three experimental methods. Good correlation was found between theoretical work of adhesion and measured energies. / Master of Science
92

Piezometry and Strain Rate Estimates Along Mid-Crustal Shear Zones

Francsis, Matthew Keegan 21 May 2012 (has links)
Dynamically recrystallized quartz microstructure and grainsize evolution along mid-crustal shear zones allows for the estimation of tectonic driving stresses and strain rates acting in the mid-crust. Quartz-rich tectonites from three exhumed mid-crustal shear zones, the Main Central Thrust (MCT; Sutlej valley, NW India), South Tibetan Detachment System (STDS; Rongbuk valley, S Tibet), and Moine thrust (NW Scotland), were analyzed. Deformation temperatures estimated from quartz microstructural and petrofabric thermometers indicate steep apparent thermal gradients (80–420 °C/km) across 0.5–2.3 km thick sample transects across each shear zone. Quartz recrystallization microstructures evolve from transitional bulging/sub-grain rotation to dominant grain boundary migration at ~ 200 m structural distance as traced away from each shear zone. Optically measured quartz grainsizes increase from ~ 30 μm nearest the shear zones to 120+ μm at the largest structural distances. First-order Zener space analysis across the Moine nappe suggests strong phyllosilicate control on recrystallized quartz grainsize. Recrystallized quartz grainsize piezometry indicates that differential stress levels sharply decrease away from the shear zones from ~ 35 MPa to 10 MPa at ~ 200 m structural distance. Strain rates estimated with quartz dislocation creep flow laws are tectonically reasonable, between 10⁻¹² – 10⁻¹⁴ s⁻¹. Traced towards each shear zone strain rate estimates first decrease one order of magnitude before rapidly increasing one to two orders of magnitude at structural distances of ~ 200 m. This kinked strain rate profile is likely due to the steep apparent thermal gradients and relatively constant differential stress levels at large structural distances. / Master of Science
93

How is a Woman Like a Watermelon?: Advocating a Psychological and Comparative Examination of Brautigan's Novels

Plummer, Sarah E. 08 June 2010 (has links)
"How is a Woman Like a Watermelon" examines two of Richard Brautigan's novels, In Watermelon Sugar and An Unfortunate Woman, as they relate to each other in ways that offer a better understanding of each. This paper enriches an understanding of Brautigan's work by exploring the historical context of his writings, studying his style and presenting diverse interpretations in a mutually inclusive way that complements the multifaceted qualities of his writing. By studying Brautigan's novels in a comparative manner, the essential and distinctive principles that drive Brautigan's work—his manipulation of genre, use of memory and a complex first person narrator as an author persona—are better understood. Because of Brautigan's use of the first person, this study advocates an analytical psychological analysis aimed at discerning underlying emotion within apparent personal detachment, the use of projection as a defense mechanism, and the psychological associative value of words, images and memories. An inclusive and comparative study that foregrounds these psychological elements will ultimately allow for a more complete and subtle analysis of Brautigan's work. / Master of Arts
94

Development of a Flotation Rate Equation from First Principles under Turbulent Flow Conditions

Sherrell, Ian M. 13 December 2004 (has links)
A flotation model has been proposed that is applicable in a turbulent environment. It is the first turbulent model that takes into account hydrodynamics of the flotation cell as well as all relevant surface forces (van der Waals, electrostatic, and hydrophobic) by use of the Extended DLVO theory. The model includes probabilities for attachment, detachment, and froth recovery as well as a collision frequency. A review of the effects fluids have on the flotation process has also been given. This includes collision frequencies, attachment and detachment energies, and how the energies of the turbulent system relate to them. Flotation experiments have been conducted to verify this model. Model predictions were comparable to experimental results with similar trends. Simulations were also run that show trends and values seen in industrial flotation systems. These simulations show the many uses of the model and how it can benefit the industries that use flotation. / Ph. D.
95

Magmatic response to the evolving New Zealand Margin of Gondwana during the Mid-Late Cretaceous

Tappenden, Vanessa Elizabeth January 2003 (has links)
The Mount Somers Volcanic Group (MSVG) and Mandamus Igneous Complex (MIC) are the magmatic manifestations of the transition from convergence to extension at the Gondwana margin, which culminated in the separation of New Zealand from Australia and Antarctica. The MIC has been correlated both geochemically and temporally with the Central Marlborough Igneous Province (CMIP). The MSVG and CMIP are located in the Eastern Province of New Zealand. The MSVG is restricted to the Rakaia terrane, whereas the CMIP is restricted to the Pahau terrane. The Rakaia and Pahau terranes are thick accretionary complexes, which were strongly deformed as a result of prolonged subduction at the Gondwana margin. The Pahau terrane is the younger of the two and continued to be deposited and deformed until the abrupt cessation of subduction, which in the Marlborough sedimentary record occurred in the Motuan (100 - 105 Ma). Following the cessation of subduction, after an interval of 2-7 Ma of relative quiescence and subsidence of the Pahau terrane, the MSVG and MIC were erupted/emplaced. The production of MSVG and MIC magmas occurred simultaneously and the activity was of short-lived duration. SHRIMP geochronology yielded crystallisation ages of 97.0 ± 1.5 Ma to 98.0 ± 1.2 Ma from zircons separated from MSVG rhyolites. The SHRIMP ages are within error of the previously published Rb-Sr age for the MIC. The SHRIMP geochronology also confirmed the presence of inherited zircons which yielded ages consistent with their derivation from the Rakaia terrane. Ar-Ar geochronology confirmed the coeval nature of the MSVG and MIC magmatism, but yielded consistently younger ages (94.5 ± 3 Ma for the MSVG and 94.2 ± 1.7 Ma for the MIC). The systematic differences in ages obtained by SHRIMP and Ar-Ar are believed to be method-dependent. The MSVG comprises a calc-alkaline volcanic assemblage, which ranges in composition from basaltic-andesite lavas (SiO₂ = 54.5%) to high-silica rhyolites and ignimbrites (SiO₂ ≤ 78.1%). The MSVG had an original extent of at least 18 000 km². The magmas from the MSVG had high LILE/HFSE, high LILE/REE and moderately high LREE/HFSE which are characteristic of subduction derived magmas. Geochemical modelling suggests that the MSVG magmas were formed from partial melting of a subduction-modified mantle wedge, with high degrees of crustal assimilation. The assimilant had an isotopic composition similar to that of the Rakaia terrane, which is consistent with the geological setting of the MSVG. The MSVG has ⁸⁷Sr/⁸⁶Sri from 0.7055 to 0.7100 and ¹⁴³Nd/¹⁴⁴Ndi from 0.51254 to 0.51230 (ɛNd +0.5 to -4.2), which reflects varying degrees of contamination by Rakaia terrane. Radiogenic isotope modelling suggests that the MSVG end-members were derived from the same parent magma, which evolved through AFC processes from basaltic-andesite to rhyolite. The modelling strongly suggests that assimilation played a lesser role in the petrogenesis of the Malvern Hills magmas than in the petrogenesis of the other units. AFC modelling requires the degree of assimilation to increase as the magmas evolved. Oxygen isotope data are consistent with high degrees of crustal assimilation, and may indicate that the assimilant had higher ¹⁸O characteristics than the Rakaia terrane samples analysed. The MIC is an alkaline suite which ranges in composition from basalt and gabbro to syenite, trachyte and phono-tephrite. The MIC is interpreted to have formed from enriched asthenospheric mantle, with a composition similar to HIMU (²⁰⁶Pb/²⁰⁴Pbi ranges from 19.2 to 20.3). The samples range in isotopic composition from ⁸⁷Sr/⁸⁶Sri = 0.7030 to 0.7036, ¹⁴³Nd/¹⁴⁴Ndi = 0.51275 to 0.51268 (ɛNd +4.6 to +3.3). The range in isotopic composition is due to varying degrees of contamination by Pahau terrane, which reaches a maximum of 25% but in most samples is < 10%. The MIC is contaminated to a much lesser extent than the MSVG which is interpreted to be related to the thinner nature of the Pahau crust in the mid-Cretaceous. The latest phases of activity in the MIC were subjected to lower degrees of contamination which is interpreted to reflect the passage of magmas through pre-existing pathways. The onset of MSVG and CMIP magmatism coincided with the initiation of major rift-related depositional basins, and the eruption of the MSVG is demonstrably associated with normal faulting. The tectonic trigger responsible for the sudden onset of magmatism and rifting in the Eastern Province terranes was the detachment of the previously subducting slab following the cessation of subduction due to the arrival of the Hikurangi Plateau at the margin and the subsequent stalling of the Pacific spreading centre. The capture of the Gondwana margin led to the propogation of extension into the margin by the divergent Pacific plate. The ensuing extension aided the detachment of the subducting slab beneath the Eastern Province terranes. The slab-detachment promoted decompression melting of the sub-lithospheric mantle wedge to produce the MSVG magmas and triggered the ascent of asthenospheric mantle through the slab window, which melted through decompression to produce the CMIP magmatism. The asthenospheric mantle tapped by the slab detachment episode was highly enriched relative to N-MORB and is akin to the similar age HIMU-OIB affinity melts documented from Antarctica and Australia. The short-lived duration of activity is typical of slab-detachment related magmatism which occurs as a passive response to plate reconfiguration. The similarity in geochemistry of the MIC with OIB-affinity igneous centres in Australia and Antarctica implies an enriched mantle domain of large geographical extent. The distribution of relatively small volumes of OIB magmatism is suggestive of a fossil plume component, which was tapped in response to lithospheric extension producing relatively short-lived HIMU magmatism. The same fossil plume component has previously been implicated in the formation of the Cenozoic West Antarctic Rift System and may be responsible for the late Cretaceous magmatism in the Chatham Islands and Tertiary volcanics of the South Island of New Zealand.
96

從超脫之理論與實踐看艾克哈特之密契主義 / The Theory and Practice of Detachment in Meister

黃恩鄰, Huang,En-Lin Unknown Date (has links)
不同於過去將密契經驗侷限於一特殊意識狀態的經驗,本文試圖從艾克哈特關於超脫 的觀點來說明密契主義和其經驗的形式如何受到其社會與時代背景所影響。 過去學者的研究說明艾克哈特關於超脫的概念,是其形而上學和密契主義的核心。但 超脫此一概念不僅是密契主義中用以顯示辯證法和否性神學的形而上概念,從艾克哈特的德 文著作中我們還可以發現該辭彙的產生與其所面對的聽眾和當下的信仰情境息息相關。 艾克哈特將信徒在信仰操作上所遇到的困境和壓力視為一種苦難的來源,因而以童貞 婦人的形象要求信徒應當轉而重視信仰的態度,以超脫的態度在入世或既有的宗教生活中實 踐其信仰,最後達到沒有原因的生活與意志的貧乏。艾克哈特關於超脫所建構出來的密契經 驗有著與其時代相關社會的、實踐的或倫理學上的生成因。 此外,透過對 Gezücken 等辭彙的探討,我們發現超脫一概念包含著形而上學、倫理 學和密契的不同層次。這些層次說明了艾克哈特對密契經驗的概念並指導他的聽眾如何正確 的對待自己的宗教經驗。超脫因而是艾克哈特密契經驗的主題,實踐和內容。 我們因而可以說,在艾克哈特的範例中,密契主義及其經驗具有不同層面,並且如同 史蒂芬卡茲所說,是一種處在宗教、文化等生活實境中所建構的經驗形式。 / By studying the concept of "Detachment" of Meister Eckhart, this article presents that the forms of mysticism and mystical experience are influenced and restricted by its own social and religious contexts. According to previous studies of scholars, the idea of "Detachment" is a central and metaphysical idea of Meister Eckhart's Mysticism. However, the idea of "Detachment" is not only a concept that contents neoplatonical idea of dialectic and negative theology but also a concept that responds to its contemporary religious trends which we can find in Eckhart's German works. Eckhart considered the heavy pressure of religious practices as sufferings and persuaded his audiences to concentrate on their own detached attitudes instead. He suggested that the life of detachment was a model of "virgin wife" that presented purest religious life in the normal daily life, and the purpose was to live without a why and to reach spiritual poverty. The mysticism of Meister Eckhart, which has "detachment" as its central idea, therefore has its social, practical, and ethical causes. Meanwhile, by studying the concept of Gezücken, we found that the idea of "Detachment" is a concept combined with metaphysical, ethical, and mystical layers. These layers presents in Eckhart's discourse about mystical experience and direct his audiences to treat their religious experiences with correct attitudes. "Detachment" therefore is both the main theme, the criteria, and the content of Eckhart's idea of mystical experiences. We can finally conclude that, like Steven Katz's theory, in the situation of Meister Eckhart the mystical experience is a experience formulated by its own religious and cultural situations, a experience that "Sitz im Leben".
97

Anatomical and Functional Results of Endotamponade with Heavy Silicone Oil – Densiron® 68 – in Complicated Retinal Detachment

Herbrig, Erdmuth, Sandner, Dirk, Engelmann, Katrin 13 February 2014 (has links) (PDF)
Background: High-density silicone oils are newly developed long-term tamponade agents for the treatment of complicated retinal detachment in the inferior retina. Previous studies describe satisfying anatomical and functional results. In this study we examined the largest cohort so far for a 9-month follow-up and performed a comparison to conventional silicone oil. Methods: Our study documents results and adverse effects after vitreoretinal surgery and endotamponade with Densiron® 68 in 99 cases of complicated retinal detachment. A 9-month follow-up was performed. Data of 21 patients with intraocular conventional silicone oil tamponade in complicated retinal detachment were retrospectively analyzed and served as control. Results: Anatomical success was achieved in 78 of 89 eyes (87.6%) with completed follow-up; visual acuity did not change significantly (from mean preoperative logMAR 1.88 to postoperative logMAR 1.96 (p = 0.9). Compared to control a higher anatomical success but a similar number of adverse effects were observed with heavy silicone oil in vitreous. Nevertheless, patients who received Densiron 68 twice due to redetachment showed a significantly higher rate of intraocular inflammation with the tamponade agent in situ. Conclusion: Our results support the hypothesis of Densiron 68 as potent tamponade agent for complicated retinal detachment in the inferior retinal segments especially in eyes where a previous operation failed. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
98

Nelpění a oproštěnost v Tao-Te-Ťingu a u Mistra Eckarta / Detachment and Emptiness of the Tao-Te-Ching and Master Eckart

Michutová, Alena January 2013 (has links)
Title: Letting go and detachment in the Tao Te Ching and in the works of Meister Eckhart Type: Diploma thesis Author: Alena Michutová Supervisor: doc. Pavel Hošek, ThD. Site: Neratov Year of solving: 2013 Pages: 120 This diploma thesis is divided into five chapters. The first one deals with goals and methods of the work and the fifth chapter is the conclusion. The theme itself is divided into three chapters: (2) theme of detachment in the Tao Te Ching, (3) theme of detachment by Meister Eckhart, (4) comparison of the detachment in the Tao Te Ching and in the works of Meister Eckhart. The first part is concerned with the character of Laozi, the book of Tao Te Ching and its position in the Taoist canon. Then the basic terms of the Tao Te Ching, Tao, wu-wei and sameness, are examined. Consequently, the necessary analyses, which is interspersed with numerous citations from the Tao Te Ching and also from the secondary literature, follows to approach the topic "detachment in the Tao Te Ching". In the end, I briefly outline, how the idea of detachment has been devepoled in Taoist praxis from the very beginning up to the present time. The similar method for the topic of detachment by Meister Eckhart has been chosen - at first I deal with the character of Meister Eckhart, then with his Latin and German...
99

Studying divertor relevant plasmas in linear devices : experiments and transport code modelling / Etude du plasma de divertor dans les machines de plasma linéaires : expériences et modélisation avec un code de transport de bord

Jesko, Karol 10 January 2019 (has links)
Les prédictions concernant le fonctionnement des divertors de tokamak reposent généralement sur des codes de transport de bord, consistant en un code de plasma fluide associé à un code de Monte Carlo pour les espèces neutres. Les machines linéaires Magnum-PSI et Pilot-PSI chez DIFFER, produisant des plasmas comparables à ceux d'ITER ($T_e \sim 1$ eV, $n_e\sim10^{20}$ m$^{- 3}$). Dans cette thèse, les décharges de plasma ont été étudiées expérimentalement et par modélisation utilisant le code Soledge2D-Eirene afin de: a) rechercher quels phénomènes doivent être inclus dans la modélisation pour reproduire les tendances expérimentales et b) pour mieux interpréter les expériences . Expérimentalement, l’effet de la pression neutre $P_n$ a été étudié par diffusion Thomson, par une sonde de Langmuir, par spectroscopie visible et par calorimétrie. Nous avons montré qu'un faisceau de plasma peut être efficacement terminé par une couche de gaz neutre. Ensuite, à partir de comparaisons d’expériences et de simulations, nous avons montré qu’il était essentiel d’inclure les collisions élastiques entre le plasma et les molécules pour pouvoir reproduire les expériences. De plus, la $T_e$ proche de la cible est systématiquement surestimé, ce qui sous-estime le taux de recombinaison. Enfin, nous avons montré expérimentalement l’importance de l’inclusion de la recombinaison de surface dans le flux d’énergie de surface dans les plasmas à basse température. Les travaux présentés dans cette thèse contribuent à la compréhension des interactions plasma-neutre, en particulier dans les concepts de divertors plus fermés de nouvelle génération (MAST-upgrade, DIII-D). / Predictions for the operation of tokamak divertors typically rely on edge transport codes, consisting of a fluid plasma code in combination with a Monte Carlo code for neutral species. The linear devices Magnum-PSI and Pilot-PSI at DIFFER, operating with a cascaded arc plasma source that produces plasmas comparable to those expected in the ITER divertor ($T_e \sim 1 $ eV, $n_e \sim 10^{20}$m$^{-3}$). In this thesis, plasma discharges have been studied both experimentally and by modelling using the Soledge2D-Eirene code in order to a) investigate which phenomena need to be included in the modeling to reproduce experimental trends and b) provide new insights to the interpretation of experiments. Experimentally, the effect of neutral pressure $P_n$ was investigated using Thomson scattering, a Langmuir probe, visible spectroscopy and calorimetry. We have shown that a plasma beam can be effectively terminated by a blanket of neutral gas. Next, from comparisons of experiments and simulations, we have found that it is critical to include elastic collisions between the plasma and molecules if experiments are to be reproduced. Furthermore, the near-target $T_e$ is systematically overestimated by the code, underestimating the recombination rate thereby. Lastly, we have experimentally shown the importance of the inclusion of surface recombination to the surface energy flux in low temperature plasmas, an effect that is generally known but difficult to measure in fusion devices. The work presented in this thesis contributes to the understanding of plasma-neutral interactions especially in new generation, closed divertor concepts (i.e. MAST-upgrade, DIII-D).
100

A pré-história e reencontro com o tempo em Sem tecto, entre ruínas de Augusto Abelaira / Pre-history and reunion with time in Sem tecto, entre ruínas from Augusto Abelaira

Lais Martins da Costa Ribeiro 28 May 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho consiste em um estudo crítico do romance Sem tecto, entre ruínas, de Augusto Abelaira. Inicialmente é feita a análise sobre as possíveis consequências de uma apreensão descontínua e material do tempo, seus efeitos nas relações entre o protagonista e seu mundo, que se apresentam sob a forma de tédio e paralisia. Para a crítica proposta foram retomados conceitos descontinuidade e homogeneidade apresentados pelo filósofo Henri Bergson, além da noção de desligamento e desejo demonstrados pela sociologia de Zigmunt Bauman. O próximo alvo contemplado na pesquisa é a presença da memória e da lembrança indicados sob o ponto de vista contínuo do tempo, também analisados à luz da filosofia de Bergson, além do pensamento de Gilles Deleuze. A partir desse caminho investigativo é possível pensar a condição do protagonista como um confronto de si, uma experiência do tempo que traz uma revelação mediante a condição de ser tarde demais / This work provides a critical analysis on the novel Sem tecto, entre ruínas by Augusto Abelaira. In the first instance this study begans with the analysis of the possible consequences aroused by a material apprehension of time as well as its impact on relations between the protagonist and the world in which he lives, wich are presented by the feelings of boredom and paralysis. For the proposed work were taken up concepts of discontinuance and homogeneity created by the philosopher Henri Bergson, as well as the notion of detachment and desire demonstrated by the sociology of Zigmunt Bauman. The next target contemplated in the research is the presence of memory and recollection indicated under the point of view of continuous time, also examined by the philosophy of Bergson, in addition to the thought of Gilles Deleuze. Based on this investigative path is possible to consider the condition of the protagonist as a confront with itself, an experience of time that brings up a revelation upon the condition of being too late

Page generated in 0.0492 seconds