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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.
31

Optimalizace tvaru čerpání diferenciálně čerpané komory pro novou koncepci elektronového mikroskopu / Optimizing the shape of the pumping chambers differentially pumped chamber for a new concept of the electron microscope.

Polách, Ondřej January 2015 (has links)
The present work deals with electron microscopy, electron microscopy primarily environmental. The main task of the work will draft the optimal shape of the differentially pumped chamber, dividing the pressure difference between tube and chamber with sample for a new concept of an electron microscope. By ANSYS Fluent will be analyzed pumping gas. Subsequently, according to the results obtained will be a modified form of the differential Chamber and to achieve the lowest gas pressure on the track of the electron beam.
32

Elektronische Semesterapparate (ESEM): Neuer Service der SLUB für die Lehre

Küchler, Julia 23 August 2006 (has links)
Seit Sommersemester 2006 bietet die SLUB mit den Elektronischen Semesterapparaten ESEM einen neuen Service für Studenten der TU Dresden im Internet an. ...
33

Románové světy Ričardase Gavelise a Milana Kundery: Komparativní analýza / Novelistic Worlds of Ričardas Gavelis and Milan Kundera: A Comparative Analysis

Montvilaite, Geda January 2019 (has links)
Key Words: Comparatistics, Intertextuality, Essayism, Esem, Milan Kundera, Ričardas Gavelis, Laughter, Kitsch, Vulgarity, Carnevalism, Thanatos, Sexuality This comparativist thesis discusses the intelectual novel of the end of the 20th century. The study objects chosen for this paper were the works of Ričardas Gavelis and Milan Kundera. Due to the differences in the poetics of the works, it was chosen to analyze four works of each writer's large prose. In the case of Gavelis they are as follows: Vilnius Poker (Vilniaus pokeris, novel, 1989), Vilnius Jazz (Vilniaus džiazas, novel, 1993), The Last Generation of People on Earth (Paskutinioji Žemės žmonių karta, novel, 1995) and Six Ways of Suicide (Septyni savižudybės būdai, novel, 1999). From Kundera's works we picked out The Farewell Party (Valčík na rozloučenou, novel,1972), The Book of Laughter and Forgetting (Knihou smíchu a zapomnění, novel, 1978), The Unbearable Lightness of Being (Nesnesitelnou lehkostí bytí, novel, 1984) a Immortality (Nesmrtelnost in french, 1990, in czech 1993). One of the main aims of this study is to introduce the Czech reader to Ričardas Gavelis: one of the most important and influential writers of Lithuanian literature of the late 20th century. The works of this writer are not yet properly evaluated even in his native...
34

Hydrological and Paleoclimate Analysis of a Pinyon-Juniper and Fen-Dominated Watershed on the Windy Ridge Mega-Landslide

Barker, Joel Frederick 01 November 2019 (has links)
Water BudgetThis chapter documents the hydrologic analysis of a watershed within the Windy Ridge mega-landslide of Central Utah to (1) create a water budget and (2) place a quantitative limit on the magnitude of climatic changes documented by Shurtliff et al. (2017) and Hudson et al. (2019). (1) A water budget was calculated over the last four years using instrumentation and weather stations both within and surrounding the watershed, In terms of precipitation input, 85% is released by the evapotranspiration of the Pinyon-Juniper forest, 4% discharges as surface water from the base of the watershed, and 11 % infiltrates the groundwater system. This infiltration rate is slightly lower than the 15% suggested by Maxey-Eakin method (Maxey and Eakin, 1949), likely due to the less permeable, clay-rich sediment. (2) Previous studies performed on Garden Basin Cattail (GBC) Fen at the base of its watershed suggest swings from pond-like to wetland environments (Shurtliff et al, 2017; Hudson et al, 2019). This study estimated precipitation values necessary to create standing water (pond) environments. Changes in annual precipitation, as well as input from North American monsoon (NAM), may cause these environmental changes. Each of these cases were examined. Trends in piezometer measurements compared to mean annual precipitation indicated that ‰¥ 644 mm of annual precipitation are required to sustain a wet (perennial standing water) environment. The change from wetland to pond conditions may depend on seasonal trends in precipitation. This study suggests an increase of 150-300 mm of precipitation in late summer (NAM) may be connected to perennially wet conditions. The higher annual precipitation values, largely accomplished by NAM fluctuations, caused a transition from wetland to pond (Hudson et al., 2019; Shurtliff et al., 2017). Chapter 2: Core AnalysisChapter 2 further documents the watershed's historical environmental and climate record by analyzing sediment and topography surrounding GBC fen, adding to the works of Shurtliff et al. (2019) and Hudson et al. (2019). A core was extracted from GBC fen at the base of the watershed and the sediment analyzed in terms of color, texture, environmental scanning electron microscope (ESEM) imaging, RockEval pyrolysis, and 14C ages. These results were then compared to pre-existing pollen and diatom proxies completed on a previous core by Shurtliff et al. (2019). This study suggests climatic variation, along with basin fill processes, was the driver of environmental change in GBC fen (Garden Basin watershed). Climate proxies show the basic trend from a particularly wet period (12-9 ka BP) of more stagnant or deeper water, to a much dryer period of much shallower water levels (9-3 ka BP), followed by a rebound in moisture levels, especially in the past few hundred years. Although climate was the driver of transitions within GBC2 core, a pollen record of sustained shallow water plants and MASW (Park et al., 1999) survey may suggest beaver activity.
35

Scanning Methods as Monitoring, Verification, and Accounting tools for CO₂ Sequestration in Unconventional Gas Reservoirs

Amante, Joseph David 16 September 2015 (has links)
Unconventional gas reservoirs in carbon dioxide sequestration activities is a relatively new and unexplored concept currently undergoing pilot scale testing. Sequestration has the potential for enhancing gas recovery while mitigating carbon dioxide to long term storage structures. Due to the extremely complex systems associated with these unconventional reservoirs, modeling becomes difficult to predict accurately. This thesis presents methods to increase the confidence of inferred parameter testing for unconventional reservoir sequestration in both seam coal bed methane wells and a shale wells. Various tests include the use of computed tomography coupled with Avizo modeling software, inductively coupled mass spectrometer fluid transport analysis, pressure transient build tests, liquid level detection, and desorption analysis coupled with cleat image analysis. Analyses of coals performed by both environmental scanning electron microscope (ESEM) and micro CT demonstrate that distributions of cleat porosity in coals are anisotropic and not correlated to the seam depth or location. ESEM is used with micro CT scanning to verify the results before and after the impregnation of the carbonic acid. The micro CT data in Avizo Fire© was used calculate an increase in cleat permeability by 25%. The increase of major flow pathways is caused by the dissolution of carbonates. Changes in the structures were observed qualitatively through ESEM and micro CT and quantitatively through Avizo and inductively coupled mass spectrometry. The results of comparative study between the cleat structures and the desorption of various seams indicate a trend in the cleat porosity and the desorption rate of the coals as well as the cleat porosity and the total gas in various seams. / Master of Science
36

Applying scanning electron microscopy for the ultrastructural and clinical analysis of periprosthetic capsules in implant-based breast reconstruction

Paek, Laurence S. 02 1900 (has links)
La reconstruction en deux étapes par expanseur et implant est la technique la plus répandue pour la reconstruction mammmaire post mastectomie. La formation d’une capsule périprothétique est une réponse physiologique universelle à tout corps étranger présent dans le corps humain; par contre, la formation d’une capsule pathologique mène souvent à des complications et par conséquent à des résultats esthétiques sous-optimaux. Le microscope électronique à balayage (MEB) est un outil puissant qui permet d’effectuer une évaluation sans pareille de la topographie ultrastructurelle de spécimens. Le premier objectif de cette thèse est de comparer le MEB conventionnel (Hi-Vac) à une technologie plus récente, soit le MEB environnemental (ESEM), afin de déterminer si cette dernière mène à une évaluation supérieure des tissus capsulaires du sein. Le deuxième objectif est d‘appliquer la modalité de MEB supérieure et d’étudier les modifications ultrastructurelles des capsules périprothétiques chez les femmes subissant différents protocoles d’expansion de tissus dans le contexte de reconstruction mammaire prothétique. Deux études prospectives ont été réalisées afin de répondre à nos objectifs de recherche. Dix patientes ont été incluses dans la première, et 48 dans la seconde. La modalité Hi-Vac s’est avérée supérieure pour l’analyse compréhensive de tissus capsulaires mammaires. En employant le mode Hi-Vac dans notre protocole de recherche établi, un relief 3-D plus prononcé à été observé autour des expanseurs BIOCELL® dans le groupe d’approche d’intervention retardée (6 semaines). Des changements significatifs n’ont pas été observés au niveau des capsules SILTEX® dans les groupes d’approche d’intervention précoce (2 semaines) ni retardée. / Two-stage implant-based (expander to implant) breast reconstruction is the most frequently applied technique following total mastectomy. While the periprosthetic capsule is a normal physiologic response to any foreign body, pathological capsule formation often leads complications and suboptimal aesthetic results. The scanning electron microscope (SEM) is a powerful tool that offers unparalleled assessment of capsule ultrastructural topography. The first research aim was to compare conventional high-vacuum (Hi-Vac) SEM with newer environmental scanning electron microscopy (ESEM) technology to determine whether the latter offers superior assessment of breast capsular tissue. The second aim was to apply the most optimal SEM mode to study periprosthetic capsule ultrastructural modifications in women undergoing differing expansion protocols during the first stage of implant-based reconstruction. Ten patients were prospectively included in the first study and 48 prospectively included into the second. Conventional Hi-Vac mode was deemed superior for the comprehensive analysis of breast capsular tissue. Using Hi-Vac mode within the established study protocol, a more pronounced capsular 3-D relief was observed around BIOCELL® expanders when the first postoperative saline inflation took place at 6 weeks following expander insertion (delayed approach). No significant changes were observed with SILTEX® expander capsules in both early (2 weeks) and delayed approach groups.
37

Scintilační detektor sekundárních elektronů pro ESEM / Scintillation Detector of Secondary Electrons for ESEM

Čudek, Pavel January 2008 (has links)
The thesis deals with modifying and biulding of scintilation detector of secondary electrons for environmental scanning electron microscopy. It describes dilemma of environmental scanning electron microscopy, types of detectors and secondary electrons detection. The experimental part of this thesis focuses on the design and construction of new scintillation detector on the basis of simulations secondary electrons trajectories. Identifying the parameters, pressure dependencies and optimizations of electrode system of the detector realized.
38

In Situ High Temperature Environmental Scanning Electron Microscopic Investigations of Sintering Behavior in Barium Titanate

Subramaniam, Srinivas 02 October 2006 (has links)
No description available.
39

Víceelektrodový systém ionizačního detektoru pro environmentální rastrovací elektronový mikroskop / Multi-electrode system of ionization detector for environmental scanning electrone microscope

Uhlář, Vít Unknown Date (has links)
Thesis deals with environmental scanning electron microscopy and with detection of signal electrons by using ionization detector. First part talks about the principle of environmental scanning electron microscope. Second part describes signals generated by interaction of primary electron beam with sample. Third section explains the principle of impact ionization and ionization detector. Experimental part deals with usage of segmental ionization detector and with measuring of signal amplification from copper and platinum. Thesis also examines arrangement of electrodes of ionisation detector on material contrast and examines also on influence of voltage contrast on base - emitter junction of an NPN bipolar transistor. All experiments were carried out in dependency on saturated water vapour pressure in sample chamber.
40

Vyhodnocení vlivu tlaku v komoře vzorku a velikosti clonek na výsledný tlak u scintilátoru detektoru pomocí systému Cosmos FloWorks / Using Cosmos FloWorks for analyse the detector.

Bordovský, Petr January 2010 (has links)
This work deal with the analysis of influence of pressure‘s sizes in vacuum chamber of specimen Evironmental Scanning Electron Microscope and the influence of sizes of aperture diaphragm by scintillation detector. The analysis proceeds in detector of secondary electrons. The detector is modelled by system 3D CAD SolidWorks with the help of system CAE Cosmos FloWorks.

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