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Optimization of Deep-UV Lithography ProcessGupta, Kamal Kumar Unknown Date (has links)
This master’s project report deals with the process development for patterning thesub-micron features using Deep-UV photolithography. Patterning of the sub-micronstructures in the resists UV26 and ZEP520A-7 has been demonstrated successfully. Using theKarl Süss-MJB4 DUV mask aligner, trenches of width down to 535 nm have been obtained.Good results have been obtained in these experiments considering the development time andthe exposure time, which are found to be shorter compared to previously published results.This provides a faster process and higher throughput. Experimental steps along with thefurther improvement areas are discussed.Equipment used include a Karl Süss-MJB4 DUV mask aligner, an optical microscope anda Scanning Electron Microscope (SEM).
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Comparison of Epiphany® and AH-Plus® Root Canal Sealer Penetration of Dentinal Tubules: A SEM StudyJordan, Kalisha 06 May 2011 (has links)
The purpose of this study was to evaluate the effect of a final rinse of ethanol on depth of sealer penetration in teeth obturated with Gutta Percha (GP)/AH-Plus® (Dentsply, De Trey GmbH, Konstanz, Germany) or Resilon/Epiphany® SE™ (Pentron Clinical Technologies, LLC, Wallingford, CT). Extracted human anterior teeth (n= 32) were shaped to size 30, 0.06 taper using nickel-titanium rotary files and subjected to an identical irrigation protocol. Specimens were randomly divided into eight groups according to final irrigating solution (saline, 70%, 95%, or 100% ethanol) and obturation material (GP/AH-Plus® or Resilon/EpiphanyÒ SE™). A 2mm thick slice was obtained by sectioning each obturated root at 3mm and 5mm from the anatomic apex. Specimens were cleared and assessed using scanning electron microscopy (SEM). Sealer penetration was observed at different magnifications when using GP/AH Plus® across all final rinse concentrations. Among Resilon/Epiphany® SE™ groups, no sealer penetration was evident under SEM. Conclusions: 1) GP/AH-Plus® showed evidence of sealer penetration, however, Resilon/Epiphany® SE™ did not show evidence of sealer penetration at both the dentin and sealer interface. 2) A final rinse with any concentration of ethanol prior to obturation does not improve sealer penetration with GP/AH-Plus® groups. 3). Resilon/Epiphany® SE™ bond can be dislodged at either the interface of sealer and Resilon or dentin and Resilon.
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Scanning Electron Microscopic Studies on the Spores of Polypodiaceae and Grammitidaceae from TaiwanChen, Chi-Chuan 16 February 2011 (has links)
Spore morphology of Polypodiaceae and Grammitidaceae from Taiwan were studied with light microscope and scanning electron microscope. Totally 18 genera and 62 species were observed. Polypodiaceae spores are ellipsoidal and monolete except Loxogramme grammitoides; with spore ornamentation tuberculate, verrucate, echinate, globule, rugate, undulate, foveolate and/or vermiculate. Grammitidaceae spores are global, trilete with spore ornamentation granulate, tuberculate and/or globules. The spore surface ornamentation can be used as taxonomic characters in Polypodiaceae and Grammitidaceae at familial, genera and species levels.
Based on spore characters, Polypodiaceae and Grammitidaceae can be differentiated, Loxogrammeae and Drynariaeae are not separable from the rest of Polypodiaceae, and the current classification system of Lepisorieae and Microsoreae are not .internal consistent.
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Mrazová sublimace v kryonástavci Gatan Alto 2500 skenovacího elektronového mikroskopu JSM-7401F / Freezy sublimation in cryoattachement Gatan Alto 2500 connected to scanning electron microscope JSM-7401FMAROUŠEK, Roman January 2007 (has links)
This thesis deals with freezy sublimation in cryoattachement Gatan Alto 2500 connected to scanning electron microscope (SEM) JEOL JSM-7401F. The thesis is devided into the theoretical and practical parts. In the theoretical part I focus mainly on physical qualities of water and on problematics of freezy-drying. I also describe qualities of subsidiary substances which are being used when working with cryotechnology. I briefly describe technology used: cryoattachement Alto 2500 and SEM JSM-7401F. In the practical part I deal with the description of the method that I have developed in order to measure weight decrease of frozen specimen owning to its sublimation in vacuum. I provide measurement results of the sublimation of these substances: demineralized water, Dextran, glycerol and phosphate buffer saline.
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Surface structure, wax and methanol-extractable compounds in Scots pine and Norway spruce needles enhanced UV-BKinnunen, H. (Heli) 30 May 1999 (has links)
Abstract
Increased amounts of epicuticular waxes and UV-absorbing compounds, such as flavonoids, and smaller leaf/needle surface area are plant defence mechanisms against UV-B radiation. The response of the needle epicuticular waxes of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies Karst.) seedlings to increased UV-B were investigated in short-term and long-term greenhouse experiments. In a more realistic long-term field experiment with mature Scots pines, the methanol-extractable UV-absorbing compounds were also analysed.
Some significant changes were observed in the wax tube distribution (WTD, %) and the amount of waxes in Norway spruce seedlings in the short-term Belgian greenhouse experiment (UV-BBE 0, 11.3 and 22.6 kJ m-2 d-1), but no changes were detected in Scots pine seedlings. No changes in waxes were observed in the long-term Finnish greenhouse experiment (UV-BBE 0, 2.2–6.6 and 5.6–16.8 kJ m-2 d-1), where both the Norway spruce and the Scots pine seedlings seemed to respond by having smaller needle surface areas. A field experiment (UV-BBE 0.5–2.4 kJ m-2 d-1 and 0.7–5.1 kJ m-2 d-1) with mature Scots pines revealed no significant changes in WTD during the three growing seasons or the amount of waxes during the third growing season.
In the long-term field experiment the amount of UV-absorbing compounds varied significantly between seasons and/or needle age classes. Elevated amounts of these compounds were already observed in the three-day-old needles and also in the oldest (c + 2) needles when the waxes were still undeveloped or already somewhateroded. No significant differences in the amount of UV-absorbing compounds were observed between the treatments during the first and second growing seasons. During the third growing season, needles of all ages contained significantly or slightly less UV-absorbing compounds in supplemental UV-B than in the ambient treatment, possibly due to cumulative effects of UV-B in already inhibited pigment synthesis. This suggests that these defence mechanisms are not efficient enough to prevent the UV-B-induced damage in the long term.
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The influence of clay diagenesis on the petrophysical properties of sandstone reservoirs in the Pletmos Basin Offshore South AfricaMguni, Nothando January 2020 (has links)
>Magister Scientiae - MSc / Pletmos Basin is a Mesozoic half graben located in the southern part of South Africa and has undergone numerous tectonic changes which involve alteration of structure and reworking of sediments. Clay diagenesis has become a more prominent factor affecting the quality of the tight shaly sandstone reservoirs in the southern Pletmos Basin. The present study focused on Block 11a as a primary area of interest .The tight sandstone reservoirs encountered in the four wells, viz. Ga-Q1, Ga- Q2, Ga-Z1 and Ga- E2 were studied using four different methods to incorporate and infer the overall diagenetic effect on the reservoirs, caused by materials of argillaceous origin. The methods adopted in the present research are formation evaluation using wireline logs and calibration of core data using Interactive Petrophysics software, thin section petrography, X-Ray Diffraction (XRD) and, Scanning Electron Microscope (SEM) along with Energy Dispersive X-Ray Spectroscopy (EDS). The availability of core samples were limited to wells Ga- Q1 and well Ga- Z1. Four reservoirs within the Cretaceous age were identified in each well and the best reservoirs were associated with facies B and D. / 2022-04-30
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SEM Assessment of the Enamel Surface After Debonding of Ceramic BracketsKothari, Anuja 11 September 2015 (has links)
Objective: This study was conducted to compare the shear bond strengths, patterns of bond failure and enamel surfaces after debonding two ceramic brackets (ClearVu and Radiance Plus) and one standard metal bracket (Mini Uni-Twin). Background: Ceramic brackets are an esthetic alternative to metal brackets. The mean shear bond strength of ceramic brackets is significantly greater than for metal brackets. Excessive bond strength can result in pain upon debonding, damage to the bracket or permanent damage to the enamel including flaking, cracks or tooth fracture. Numerous studies have evaluated techniques to reduce the risk of enamel damage when debonding ceramic brackets, including the use of debonding pliers. Debonding pliers produce a concentrated stress within the adhesive, resulting in cohesive failures within the resin or adhesive failures outside the resin. Methods: A total of 75 caries-free extracted human premolar teeth were randomly divided into 3 groups: ClearVu ceramic bracket (TP Orthodontics, LaPorte, IN), Radiance Plus ceramic bracket (American Orthodontics, Sheboygan, WI) and Mini Uni-Twin metal bracket (3M Unitek, Monrovia, CA). The Instron Universal Testing Machine Model 8841 with a customized jig with a bracket removing plier was used to debond the brackets. The teeth were microscopically evaluated to determine the location of bond failure. Selected teeth were evaluated with the scanning electron microscope to evaluate for enamel cracks and tear-outs. Results: A one-way ANOVA was created and no significant differences in shear bond strength were discovered between the three groups. Using a chi-square test of independence it was determined that the brackets all possessed a different ARI score. After examining the standardized residuals, we found that Radiance Plus Ceramic bracket and ClearVu Ceramic bracket were both likely to have favorable bond failure patterns, compared to the Mini Uni-Twin Metal bracket. Radiance Plus was most likely to debond at the bracket-adhesive surface, with a majority or all of the adhesive on the tooth after debond. Teeth with unfavorable bond failure patterns (ARI score of 0 or 1) were evaluated with the scanning electron microscope. 11% of the total teeth in the study had enamel damage, including cracks and tear-outs. 62.5% of these teeth were from the ClearVu ceramic bracket group. Conclusions: Our results show that both Radiance Plus ceramic bracket and ClearVu ceramic brackets are comparable to the gold standard metal bracket used in this study, the Mini Uni-Twin, in terms of shear bond strength. Radiance Plus ceramic bracket had the most favorable bond failure pattern, but shattered more during debonding. ClearVu ceramic bracket had the most enamel damage when evaluated with the scanning electron microscope. American Orthodontics’ Radiance Plus Ceramic bracket is the recommended bracket of those studied.
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Duricrusts ferruginosos da Serra do Espinhaço Meridional (MG) e suas relações com a evolução da paisagem / Iron-rich duricrust of Serra da Espinhaço Meridional, Minas Gerais State, Brazil and their relations with landscape evolutionCamêlo, Danilo de Lima 22 February 2017 (has links)
Algumas indicações morfológicas sugerem que as superfícies de paisagem tropicais onde encontram-se os duricrusts ferruginosos, podem apresentar idades que variam desde o Quaternário até o Cretáceo, e que a laterização sobre estas superfícies pode ter sido iniciada simultaneamente ou não, estabelecendo-se uma sequência cronológica de formação escalonada de acordo com a elevação, em função da evolução geomorfológica das superfícies. Sabendo-se que no Planalto de Diamantina na Serra do Espinhaço Meridional (SdEM) são reconhecidos três níveis geomorfológicos correlatos aos ciclos de aplainamento da plataforma Sul-americana, o objetivo deste trabalho foi estudar as variações mineralógicas, geoquímicas e morfológicas de duricrusts ferruginosos da Serra do Espinhaço Meridional buscando entender os processos genéticos envolvidos e as implicações disto sobre a distribuição e evolução da paisagem regional e suas relações com os ciclos de aplainamento do continente Sul-americano. Para atingir estes objetivos, foram realizadas análises de difratometria de raios X, suscetibilidade magnética, microscopia eletrônica de varredura com sistema de energia dispersiva acoplado e análise elementar a partir da dissolução total dos minerais constituintes. Os resultados mostraram que no Planalto de Diamantina na SdEM coexistem níveis de ferricretes e lateritas na superfície correspondente ao ciclo erosivo Pós-Gondwanico. As superfícies lateríticas são provavelmente as formações supérgenas mais antigas da paisagem regional, originadas durante os processos denudacionais que ocorreram ao longo do ciclo erosivo Pós-Gondwanico. A erosão parcial de seu perfil laterítico constituíram o material fonte de Fe e Al para a gênese dos ferricretes distribuídos em superfícies elevadas (> 1200 m), especialmente aqueles em superfícies em torno de 1400 m de altitude. As variações paleoclimáticas do ciclo Pós-Gondwanico também proporcionaram ciclos erosivos alternados que resultaram no subescalonamento desta superfície, criando condições geomorfológicas favoráveis à gênese de ferricretes mais recentes (1200 - 1400 m). Além disso, os duricrusts ferruginosos do Planalto Diamantina (SdEM) sob influência do maciço quartzítico do Supergrupo Espinhaço e situados superfícies erosivas elevadas (> 1200 m), além de policíclicos, também podem apresentar características poligenéticas. / Some morphological indications suggest that the tropical landscape surfaces where the iron-rich duricrust are present may have ages varying from the Quaternary to the Cretaceous, and that the laterization on these surfaces may have been initiated simultaneously or not, establishing a sequence chronological formation according to the elevation, according to the geomorphological evolution of the surfaces. Three geomorphological levels correlated to the South American platform planing cycles are known on the Diamantina Plateau, for this the objective of this work was to study the mineralogical, geochemical and morphological variations of the iron-rich duricrust of the SdEM, trying to understand the genetic processes involved and the implications of this on the distribution and evolution of the regional landscape and its relations with the planning cycles of the South American continent. In order to reach these objectives, X-ray diffraction, magnetic susceptibility, scanning electron microscopy with dispersive energy system coupled and elemental analysis carried out from the total dissolution of the constituent minerals. The results showed that in the Diamantina Plateau at the SdEM, coexist levels of ferricretes and laterites on the surface corresponding to the Post-Gondwanic erosive cycle. The laterite surfaces are probably the oldest surviving formations of the regional landscape, originated during the denudation processes that occurred along the Post-Gondwanic erosive cycle. Partial erosion of its lateritic profile was source material of Fe and Al for the genesis of ferricretes distributed on high surfaces (> 1200 m), especially those on surfaces at 1400 m of altitude. The paleoclimatic variations of the Post-Gondwanic cycle also provided alternating erosive cycles that resulted in sub-scaling of this surface, creating geomorphological conditions favorable for genesis of earlier ferricretes (1200 - 1400 m). In addition, the ferricretes of the Diamantina Plateau (SdEM) under influence of the Quartzite massif of the Espinhaço Supergroup and located in elevated erosive surfaces (> 1200 m), besides polycyclics, may also present polygenetic characteristics.
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Duricrusts ferruginosos da Serra do Espinhaço Meridional (MG) e suas relações com a evolução da paisagem / Iron-rich duricrust of Serra da Espinhaço Meridional, Minas Gerais State, Brazil and their relations with landscape evolutionDanilo de Lima Camêlo 22 February 2017 (has links)
Algumas indicações morfológicas sugerem que as superfícies de paisagem tropicais onde encontram-se os duricrusts ferruginosos, podem apresentar idades que variam desde o Quaternário até o Cretáceo, e que a laterização sobre estas superfícies pode ter sido iniciada simultaneamente ou não, estabelecendo-se uma sequência cronológica de formação escalonada de acordo com a elevação, em função da evolução geomorfológica das superfícies. Sabendo-se que no Planalto de Diamantina na Serra do Espinhaço Meridional (SdEM) são reconhecidos três níveis geomorfológicos correlatos aos ciclos de aplainamento da plataforma Sul-americana, o objetivo deste trabalho foi estudar as variações mineralógicas, geoquímicas e morfológicas de duricrusts ferruginosos da Serra do Espinhaço Meridional buscando entender os processos genéticos envolvidos e as implicações disto sobre a distribuição e evolução da paisagem regional e suas relações com os ciclos de aplainamento do continente Sul-americano. Para atingir estes objetivos, foram realizadas análises de difratometria de raios X, suscetibilidade magnética, microscopia eletrônica de varredura com sistema de energia dispersiva acoplado e análise elementar a partir da dissolução total dos minerais constituintes. Os resultados mostraram que no Planalto de Diamantina na SdEM coexistem níveis de ferricretes e lateritas na superfície correspondente ao ciclo erosivo Pós-Gondwanico. As superfícies lateríticas são provavelmente as formações supérgenas mais antigas da paisagem regional, originadas durante os processos denudacionais que ocorreram ao longo do ciclo erosivo Pós-Gondwanico. A erosão parcial de seu perfil laterítico constituíram o material fonte de Fe e Al para a gênese dos ferricretes distribuídos em superfícies elevadas (> 1200 m), especialmente aqueles em superfícies em torno de 1400 m de altitude. As variações paleoclimáticas do ciclo Pós-Gondwanico também proporcionaram ciclos erosivos alternados que resultaram no subescalonamento desta superfície, criando condições geomorfológicas favoráveis à gênese de ferricretes mais recentes (1200 - 1400 m). Além disso, os duricrusts ferruginosos do Planalto Diamantina (SdEM) sob influência do maciço quartzítico do Supergrupo Espinhaço e situados superfícies erosivas elevadas (> 1200 m), além de policíclicos, também podem apresentar características poligenéticas. / Some morphological indications suggest that the tropical landscape surfaces where the iron-rich duricrust are present may have ages varying from the Quaternary to the Cretaceous, and that the laterization on these surfaces may have been initiated simultaneously or not, establishing a sequence chronological formation according to the elevation, according to the geomorphological evolution of the surfaces. Three geomorphological levels correlated to the South American platform planing cycles are known on the Diamantina Plateau, for this the objective of this work was to study the mineralogical, geochemical and morphological variations of the iron-rich duricrust of the SdEM, trying to understand the genetic processes involved and the implications of this on the distribution and evolution of the regional landscape and its relations with the planning cycles of the South American continent. In order to reach these objectives, X-ray diffraction, magnetic susceptibility, scanning electron microscopy with dispersive energy system coupled and elemental analysis carried out from the total dissolution of the constituent minerals. The results showed that in the Diamantina Plateau at the SdEM, coexist levels of ferricretes and laterites on the surface corresponding to the Post-Gondwanic erosive cycle. The laterite surfaces are probably the oldest surviving formations of the regional landscape, originated during the denudation processes that occurred along the Post-Gondwanic erosive cycle. Partial erosion of its lateritic profile was source material of Fe and Al for the genesis of ferricretes distributed on high surfaces (> 1200 m), especially those on surfaces at 1400 m of altitude. The paleoclimatic variations of the Post-Gondwanic cycle also provided alternating erosive cycles that resulted in sub-scaling of this surface, creating geomorphological conditions favorable for genesis of earlier ferricretes (1200 - 1400 m). In addition, the ferricretes of the Diamantina Plateau (SdEM) under influence of the Quartzite massif of the Espinhaço Supergroup and located in elevated erosive surfaces (> 1200 m), besides polycyclics, may also present polygenetic characteristics.
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Fracture scaling and diagenesisHooker, John Noel 25 February 2013 (has links)
Sets of natural opening-mode fractures in sedimentary rocks may show a variety of types of aperture-size distributions. A frequently documented size distribution type, in the literature and in data presented here, is the power law. The emergence of power-law distributions of fracture aperture and length sizes has been simulated using various quasi-mechanical fracture-growth routines but models based on linear-elastic fracture mechanics rarely produce such patterns. I collected a fracture-size dataset of unprecedented size and resolution using core and field methods and scanning electron microscope-based cathodoluminescence (SEM-CL) images. This dataset confirms the prevalence of power laws with a narrow range of power-law exponents among fractures that contain synkinematic cement. Organized microfractures are ubiquitous in sandstones. A fracture-growth simulation I devised reproduces observed size-scaling patterns by distributing fracture-opening increments among actively growing fractures. The simulated opening increments have a uniform size, which can be specified; uniform opening size is consistent with observations of narrow ranges of micron-scale widths of opening increments within crack-seal texture in natural fractures. Thus power-law size scaling of natural fractures can be explained using non-power-law (uniform-sized) opening increments, arranged using rules designed to simulate the effects of cement precipitation during fracture opening. A fundamental shortcoming of previous models of fracture-set evolution is the absence of a test because only natural fracture end states, not growth histories, could be measured. Using a technique to constrain fracture timing based on fluid inclusion microthermometry and thermal history modeling, I tested growth models by reconstructing the opening history of a set of natural fractures in the Triassic El Alamar Formation in northeast Mexico. The natural-fracture data show that, consistent with simulations, new microscopic fractures are continually introduced during natural fracture pattern evolution. As well, larger fractures represent sites of concentrated reactivation, although smaller fractures may be reactivated after long periods of quiescence. The pattern likely arises through feedback between fracture growth and the mechanically adhesive effects of contemporaneous fracture cement deposition. The narrow range in power-law exponents documented among fractures can help improve estimates of meter-scale large-fracture spacing where limited fracture samples are available. / text
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