• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 37
  • 10
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 63
  • 63
  • 36
  • 33
  • 33
  • 31
  • 29
  • 16
  • 16
  • 12
  • 11
  • 11
  • 11
  • 11
  • 10
  • 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.
1

Sêmen da cauda do epidídimo de garanhões submetido à centrifugação com coloide / Epididymal stallion semen submitted to centrifugation with colloid

Santos, Fernanda Carlini Cunha dos January 2017 (has links)
A coleta de sêmen da cauda do epidídimo é a última oportunidade de obter espermatozoides de garanhões valiosos, sendo que durante a criopreservação, a etapa de centrifugação é considerada um ponto crítico. A principal hipótese é que a centrifugação com coloides pode melhorar a qualidade dos espermatozoides coletados da cauda do epidídimo de garanhões. Para avaliação da hipótese foram realizados dois experimentos. O experimento um teve por objetivo avaliar o efeito da centrifugação com cushion e com coloide em camada única (SLC) na motilidade de sêmen do epidídimo de garanhões após a etapa de centrifugação. O experimento dois teve o objetivo de determinar o efeito da SLC prévio ao congelamento e após o descongelamento. Experimento 1) Oito garanhões foram submetidos à orquiectomia bilateral e o sêmen foi coletado da cauda dos epidídimos (n=16). Após a coleta, as amostras foram submetidas a três protocolos de centrifugação: Convencional (20 minutos a 600xg), cushioned (20 minutos a 900xg) e SLC (20 minutos a 300xg). Os pellets foram ressuspendidos e as amostras foram submetidas à avaliação laboratorial de motilidade e morfologia espermática. Experimento 2) Dez garanhões foram submetidos a orquiectomia bilateral e o sêmen foi coletado da cauda dos epidídimos (n=20). Para criopreservação, as amostras foram submetidas a: centrifugação convencional (20 minutos a 600xg), SLC prévio a criopreservação (SLC-Pre) (20 minutos a 300xg) e SLC após a criopreservação (SLC+) (20 minutos a 600xg seguidos de uma segunda centrifugação descrita após descongelamento). Os pellets foram ressuspendidos em diluente de congelamento, submetidos ao processo de congelamento em nitrogênio líquido e descongelamento. Os grupos de 6 centrifugação convencional e SLC-Pre foram avaliados imediatamente após descongelamento. O grupo SLC+ foi descongelado e submetido à SLC (20 minutos a 300xg) e ressupendido em diluente de congelamento (SLC+F) ou resfriamento (SLC+C). A motilidade total e a motilidade progressiva das amostras foram avaliadas com análise computadorizada do movimento espermático. A morfologia foi avaliada com auxílio de microscópio com contraste de fase. Funcionalidade de mitocôndria, integridade de membrana e DNA foram avaliados com auxílio de microscópio de fluorescência. Os dados foram analisados por estatística descritiva, simple one-way ANOVA e Teste de Tukey. Experimento 1) a motilidade de espermatozoide submetidos à SLC (p<0,05) e cushion (p>0,05) foi superior do que os submetidos a centrifugação convencional. Experimento 2) SLC-Pre e SLC+F apresentaram maior motilidade total, enquanto SLC+F apresentou maior motilidade progressiva. O percentual de espermatozoides com morfologia normal foi maior em SLC-Pre e SLC+F. A funcionalidade de mitocôndria foi maior em todos grupos com SLC, enquanto a integridade de membrana foi maior em SLC-Pre. A centrifugação com coloides melhorou a qualidade de espermatozoides coletados da cauda do epidídimo de garanhões, tanto no momento prévio ao congelamento como após o descongelamento. / Epididymis cauda sperm recovery and cryopreservation are last opportunity to obtain spermatozoa from a valuable animal, even though during cryopreservation centrifugation step is considered as a critical point. It is hypothesized that colloidal centrifugation could enhance epididymal stallion sperm parameters. To evaluate this hypothesis two experiments were performed. In experiment one, the objective was to evaluate the effect of cushioned and Single Layer Centrifugation (SLC) on epididymal stallion sperm motility postcentrifugation. In experiment two, the objective was to determine the effect of SLC on epididymal stallion sperm quality pre-freezing and post-thawing. Experiment 1) Eight stallions were submitted to bilateral orchiectomy and the resulting epididymal cauda (n = 16) were flushed with semen extender. After harvesting, samples were submitted to three centrifugation protocols: conventional (20 minutes at 600xg), cushioned (20 minutes at 900xg), and SLC (20 minutes at 300xg). Pellets were resuspended, motility and morphology were evaluated. Experiment 2) Ten stallions were submitted to bilateral orchiectomy and epididymal cauda (n=20) were harvested. For cryopreservation, epididymal sperm were submitted to: conventional centrifugation (20 minutes at 600xg), Single Layer Centrifugation prior cryopreservation (SLC-Pre) (20 minutes at 300xg) and Single Layer Centrifugation after cryopreservation (SLC+) (20 minutes at 600xg followed by a second centrifugation described after thawing). Pellets were resuspended in freezing extender, submitted to cryopreservation process in liquid nitrogen and thawed. Conventional and SLC-Pre were evaluated immediately after thawing. SLC+ samples were thawed, submitted to SLC (20 minutes at 300xg) and the pellets were resuspended with freezing (SLC+F) and cooling extender (SLC+C). Total motility (TM) and progressive 8 motility (PM) were evaluated with computer-assisted semen analyses. Sperm morphology was evaluated under a phase-contrast microscope. Mitochondrial functionality, membrane e DNA integrity were evaluated with an epifluorescence microscope. Data was evaluated by descriptive statistics, simple one-way ANOVA and comparison between means by Tukey test. Significance was assigned to all values p<0.05. Experiment 1) Motility of spermatozoa recovered by SLC (p<0.05) and cushioned centrifugation (p>0.05) were higher than those recovered by conventional centrifugation. Experiment 2) SLC-Pre and SLC+F yielded the highest TM, while SLC+F yielded the highest PM. Higher morphological normal sperm was observed in SLC-Pre and SLC+F. Mitochondrial functionality was significantly higher in all treatments with SLC, while membrane integrity was higher in SLC-Pre. Colloidal centrifugation improved epididymal sperm quality before freezing and after thawing.
2

Analyzing an Equivalent Single Layer Shim Model to be used for Brake Squeal Reduction

Özdemir, Hulya, Abbas, Azad January 2011 (has links)
The goal in this thesis was to reduce a multilayer shim model, which was modeled from steel and polymer (isotropic materials), into an equivalent single layer shim model. The procedure was to use mathematical formulations to convert a multilayer shim into an ESL (equivalent single layer) shim. Here, a transverse isotropic model is used to prepare for future orthotropic layers. The results show that the ESL model behaves isotropically. In the 2 layer model there was no squeal noise whereas in the ESL models there is.
3

Characterizing the Performance of a Single-layer Fabric System through a Heat and Mass Transfer Model

Ding, Dan Unknown Date
No description available.
4

Characterizing the Performance of a Single-layer Fabric System through a Heat and Mass Transfer Model

Ding, Dan 06 1900 (has links)
A mathematical model is developed to study the coupled heat and moisture transfer through a fabric system that consists of a single layer of fabric and an air gap. Properties of air and moisture are sensitive to temperature and hence are assumed to be functions of local temperature. Therefore the model is applicable to a broad range of boundary conditions. A numerical scheme is proposed to solve the distributions of temperature and moisture concentration throughout the layers, from which the thermal and evaporative resistances of the fabric system can be evaluated. Experiments are conducted for two particular fabrics using a sweating guarded hotplate, and the data show good agreement with the model predictions. Using this model, the effects of parameters in environmental conditions, air gap and material properties on the thermal and evaporative resistances are studied. This work provides fundamental basis for the optimization of garment fit and material properties to achieve good performance for the clothing system.
5

Sêmen da cauda do epidídimo de garanhões submetido à centrifugação com coloide / Epididymal stallion semen submitted to centrifugation with colloid

Santos, Fernanda Carlini Cunha dos January 2017 (has links)
A coleta de sêmen da cauda do epidídimo é a última oportunidade de obter espermatozoides de garanhões valiosos, sendo que durante a criopreservação, a etapa de centrifugação é considerada um ponto crítico. A principal hipótese é que a centrifugação com coloides pode melhorar a qualidade dos espermatozoides coletados da cauda do epidídimo de garanhões. Para avaliação da hipótese foram realizados dois experimentos. O experimento um teve por objetivo avaliar o efeito da centrifugação com cushion e com coloide em camada única (SLC) na motilidade de sêmen do epidídimo de garanhões após a etapa de centrifugação. O experimento dois teve o objetivo de determinar o efeito da SLC prévio ao congelamento e após o descongelamento. Experimento 1) Oito garanhões foram submetidos à orquiectomia bilateral e o sêmen foi coletado da cauda dos epidídimos (n=16). Após a coleta, as amostras foram submetidas a três protocolos de centrifugação: Convencional (20 minutos a 600xg), cushioned (20 minutos a 900xg) e SLC (20 minutos a 300xg). Os pellets foram ressuspendidos e as amostras foram submetidas à avaliação laboratorial de motilidade e morfologia espermática. Experimento 2) Dez garanhões foram submetidos a orquiectomia bilateral e o sêmen foi coletado da cauda dos epidídimos (n=20). Para criopreservação, as amostras foram submetidas a: centrifugação convencional (20 minutos a 600xg), SLC prévio a criopreservação (SLC-Pre) (20 minutos a 300xg) e SLC após a criopreservação (SLC+) (20 minutos a 600xg seguidos de uma segunda centrifugação descrita após descongelamento). Os pellets foram ressuspendidos em diluente de congelamento, submetidos ao processo de congelamento em nitrogênio líquido e descongelamento. Os grupos de 6 centrifugação convencional e SLC-Pre foram avaliados imediatamente após descongelamento. O grupo SLC+ foi descongelado e submetido à SLC (20 minutos a 300xg) e ressupendido em diluente de congelamento (SLC+F) ou resfriamento (SLC+C). A motilidade total e a motilidade progressiva das amostras foram avaliadas com análise computadorizada do movimento espermático. A morfologia foi avaliada com auxílio de microscópio com contraste de fase. Funcionalidade de mitocôndria, integridade de membrana e DNA foram avaliados com auxílio de microscópio de fluorescência. Os dados foram analisados por estatística descritiva, simple one-way ANOVA e Teste de Tukey. Experimento 1) a motilidade de espermatozoide submetidos à SLC (p<0,05) e cushion (p>0,05) foi superior do que os submetidos a centrifugação convencional. Experimento 2) SLC-Pre e SLC+F apresentaram maior motilidade total, enquanto SLC+F apresentou maior motilidade progressiva. O percentual de espermatozoides com morfologia normal foi maior em SLC-Pre e SLC+F. A funcionalidade de mitocôndria foi maior em todos grupos com SLC, enquanto a integridade de membrana foi maior em SLC-Pre. A centrifugação com coloides melhorou a qualidade de espermatozoides coletados da cauda do epidídimo de garanhões, tanto no momento prévio ao congelamento como após o descongelamento. / Epididymis cauda sperm recovery and cryopreservation are last opportunity to obtain spermatozoa from a valuable animal, even though during cryopreservation centrifugation step is considered as a critical point. It is hypothesized that colloidal centrifugation could enhance epididymal stallion sperm parameters. To evaluate this hypothesis two experiments were performed. In experiment one, the objective was to evaluate the effect of cushioned and Single Layer Centrifugation (SLC) on epididymal stallion sperm motility postcentrifugation. In experiment two, the objective was to determine the effect of SLC on epididymal stallion sperm quality pre-freezing and post-thawing. Experiment 1) Eight stallions were submitted to bilateral orchiectomy and the resulting epididymal cauda (n = 16) were flushed with semen extender. After harvesting, samples were submitted to three centrifugation protocols: conventional (20 minutes at 600xg), cushioned (20 minutes at 900xg), and SLC (20 minutes at 300xg). Pellets were resuspended, motility and morphology were evaluated. Experiment 2) Ten stallions were submitted to bilateral orchiectomy and epididymal cauda (n=20) were harvested. For cryopreservation, epididymal sperm were submitted to: conventional centrifugation (20 minutes at 600xg), Single Layer Centrifugation prior cryopreservation (SLC-Pre) (20 minutes at 300xg) and Single Layer Centrifugation after cryopreservation (SLC+) (20 minutes at 600xg followed by a second centrifugation described after thawing). Pellets were resuspended in freezing extender, submitted to cryopreservation process in liquid nitrogen and thawed. Conventional and SLC-Pre were evaluated immediately after thawing. SLC+ samples were thawed, submitted to SLC (20 minutes at 300xg) and the pellets were resuspended with freezing (SLC+F) and cooling extender (SLC+C). Total motility (TM) and progressive 8 motility (PM) were evaluated with computer-assisted semen analyses. Sperm morphology was evaluated under a phase-contrast microscope. Mitochondrial functionality, membrane e DNA integrity were evaluated with an epifluorescence microscope. Data was evaluated by descriptive statistics, simple one-way ANOVA and comparison between means by Tukey test. Significance was assigned to all values p<0.05. Experiment 1) Motility of spermatozoa recovered by SLC (p<0.05) and cushioned centrifugation (p>0.05) were higher than those recovered by conventional centrifugation. Experiment 2) SLC-Pre and SLC+F yielded the highest TM, while SLC+F yielded the highest PM. Higher morphological normal sperm was observed in SLC-Pre and SLC+F. Mitochondrial functionality was significantly higher in all treatments with SLC, while membrane integrity was higher in SLC-Pre. Colloidal centrifugation improved epididymal sperm quality before freezing and after thawing.
6

Sêmen da cauda do epidídimo de garanhões submetido à centrifugação com coloide / Epididymal stallion semen submitted to centrifugation with colloid

Santos, Fernanda Carlini Cunha dos January 2017 (has links)
A coleta de sêmen da cauda do epidídimo é a última oportunidade de obter espermatozoides de garanhões valiosos, sendo que durante a criopreservação, a etapa de centrifugação é considerada um ponto crítico. A principal hipótese é que a centrifugação com coloides pode melhorar a qualidade dos espermatozoides coletados da cauda do epidídimo de garanhões. Para avaliação da hipótese foram realizados dois experimentos. O experimento um teve por objetivo avaliar o efeito da centrifugação com cushion e com coloide em camada única (SLC) na motilidade de sêmen do epidídimo de garanhões após a etapa de centrifugação. O experimento dois teve o objetivo de determinar o efeito da SLC prévio ao congelamento e após o descongelamento. Experimento 1) Oito garanhões foram submetidos à orquiectomia bilateral e o sêmen foi coletado da cauda dos epidídimos (n=16). Após a coleta, as amostras foram submetidas a três protocolos de centrifugação: Convencional (20 minutos a 600xg), cushioned (20 minutos a 900xg) e SLC (20 minutos a 300xg). Os pellets foram ressuspendidos e as amostras foram submetidas à avaliação laboratorial de motilidade e morfologia espermática. Experimento 2) Dez garanhões foram submetidos a orquiectomia bilateral e o sêmen foi coletado da cauda dos epidídimos (n=20). Para criopreservação, as amostras foram submetidas a: centrifugação convencional (20 minutos a 600xg), SLC prévio a criopreservação (SLC-Pre) (20 minutos a 300xg) e SLC após a criopreservação (SLC+) (20 minutos a 600xg seguidos de uma segunda centrifugação descrita após descongelamento). Os pellets foram ressuspendidos em diluente de congelamento, submetidos ao processo de congelamento em nitrogênio líquido e descongelamento. Os grupos de 6 centrifugação convencional e SLC-Pre foram avaliados imediatamente após descongelamento. O grupo SLC+ foi descongelado e submetido à SLC (20 minutos a 300xg) e ressupendido em diluente de congelamento (SLC+F) ou resfriamento (SLC+C). A motilidade total e a motilidade progressiva das amostras foram avaliadas com análise computadorizada do movimento espermático. A morfologia foi avaliada com auxílio de microscópio com contraste de fase. Funcionalidade de mitocôndria, integridade de membrana e DNA foram avaliados com auxílio de microscópio de fluorescência. Os dados foram analisados por estatística descritiva, simple one-way ANOVA e Teste de Tukey. Experimento 1) a motilidade de espermatozoide submetidos à SLC (p<0,05) e cushion (p>0,05) foi superior do que os submetidos a centrifugação convencional. Experimento 2) SLC-Pre e SLC+F apresentaram maior motilidade total, enquanto SLC+F apresentou maior motilidade progressiva. O percentual de espermatozoides com morfologia normal foi maior em SLC-Pre e SLC+F. A funcionalidade de mitocôndria foi maior em todos grupos com SLC, enquanto a integridade de membrana foi maior em SLC-Pre. A centrifugação com coloides melhorou a qualidade de espermatozoides coletados da cauda do epidídimo de garanhões, tanto no momento prévio ao congelamento como após o descongelamento. / Epididymis cauda sperm recovery and cryopreservation are last opportunity to obtain spermatozoa from a valuable animal, even though during cryopreservation centrifugation step is considered as a critical point. It is hypothesized that colloidal centrifugation could enhance epididymal stallion sperm parameters. To evaluate this hypothesis two experiments were performed. In experiment one, the objective was to evaluate the effect of cushioned and Single Layer Centrifugation (SLC) on epididymal stallion sperm motility postcentrifugation. In experiment two, the objective was to determine the effect of SLC on epididymal stallion sperm quality pre-freezing and post-thawing. Experiment 1) Eight stallions were submitted to bilateral orchiectomy and the resulting epididymal cauda (n = 16) were flushed with semen extender. After harvesting, samples were submitted to three centrifugation protocols: conventional (20 minutes at 600xg), cushioned (20 minutes at 900xg), and SLC (20 minutes at 300xg). Pellets were resuspended, motility and morphology were evaluated. Experiment 2) Ten stallions were submitted to bilateral orchiectomy and epididymal cauda (n=20) were harvested. For cryopreservation, epididymal sperm were submitted to: conventional centrifugation (20 minutes at 600xg), Single Layer Centrifugation prior cryopreservation (SLC-Pre) (20 minutes at 300xg) and Single Layer Centrifugation after cryopreservation (SLC+) (20 minutes at 600xg followed by a second centrifugation described after thawing). Pellets were resuspended in freezing extender, submitted to cryopreservation process in liquid nitrogen and thawed. Conventional and SLC-Pre were evaluated immediately after thawing. SLC+ samples were thawed, submitted to SLC (20 minutes at 300xg) and the pellets were resuspended with freezing (SLC+F) and cooling extender (SLC+C). Total motility (TM) and progressive 8 motility (PM) were evaluated with computer-assisted semen analyses. Sperm morphology was evaluated under a phase-contrast microscope. Mitochondrial functionality, membrane e DNA integrity were evaluated with an epifluorescence microscope. Data was evaluated by descriptive statistics, simple one-way ANOVA and comparison between means by Tukey test. Significance was assigned to all values p<0.05. Experiment 1) Motility of spermatozoa recovered by SLC (p<0.05) and cushioned centrifugation (p>0.05) were higher than those recovered by conventional centrifugation. Experiment 2) SLC-Pre and SLC+F yielded the highest TM, while SLC+F yielded the highest PM. Higher morphological normal sperm was observed in SLC-Pre and SLC+F. Mitochondrial functionality was significantly higher in all treatments with SLC, while membrane integrity was higher in SLC-Pre. Colloidal centrifugation improved epididymal sperm quality before freezing and after thawing.
7

Behaviour of the boundary potentials and boundary integral solution of the time fractional diffusion equation

Kemppainen, J. (Jukka) 31 March 2010 (has links)
Abstract The dissertation considers the time fractional diffusion equation (TFDE) with the Dirichlet boundary condition in the sub-diffusion case, i.e. the order of the time derivative is α ∈ (0,1). In the thesis we have studied the solvability of TFDE by the method of layer potentials. We have shown that both the single layer potential and the double layer potential approaches lead to integral equations which are uniquely solvable. The dissertation consists of four articles and a summary section. The first article presents the solution for the time fractional diffusion equation in terms of the single layer potential. In the second and third article we have studied the boundary behaviour of the layer potentials for TFDE. The fourth paper considers the spline collocation method to solve the boundary integral equation related to TFDE. In the summary part we have proved that TFDE has a unique solution and the solution is given by the double layer potential when the lateral boundary of a bounded domain admits C1 regularity. Also, we have proved that the solution depends continuously on the datum in the sense that a nontangential maximal function of the solution is norm bounded from above by the datum in L2(ΣT). If the datum belongs to the space H1,α/2(ΣT), we have proved that the nontangential function of the gradient of the solution is norm bounded from above by the datum in H1,α/2(ΣT).
8

On Spectral Properties of Single Layer Potentials

Zoalroshd, Seyed 28 June 2016 (has links)
We show that the singular numbers of single layer potentials on smooth curves asymptotically behave like O(1/n). For the curves with singularities, as long as they contain a smooth sub-arc, the resulting single layer potentials are never trace-class. We provide upper bounds for the operator and the Hilbert-Schmidt norms of single layer potentials on smooth and chord-arc curves. Regarding the injectivity of single layer potentials on planar curves, we prove that among single layer potentials on dilations of a given curve, only one yields a non-injective single layer potential. A criterion for injectivity of single layer potentials on ellipses is given. We establish an isoperimetric inequality for Schatten p−norms of logarithmic potentials over quadrilaterals and its analogue for Newtonian potentials on parallelepipeds.
9

Administrativní budova v Brně / The administrative object in Brno

Muňko, Matej January 2019 (has links)
The subject of this work is a new administrative building in Brno, district Brno – Stred. The aim of this work is to create documentation for realization. Building has twelve floors, while every floor is rotated by 5° relative to the previous floor counterclokwise. Final rotation between the first and the last floor is 60°. On the first floor there is a restaurant, on the next eleven floors there are administrative spaces. Building is without basement and has a single-layer flat roof. The foundations are made from a system of piles, which co-work with the waterproof foundation slab. Whole construction system is made from cast-in-place reinforced conrete.
10

Thin linear-to-circular polarizers with enhanced bandwidth

Van den Berg, Monique January 2018 (has links)
Circular polarization is valuable for many electromagnetic radiation applications such as wireless and satellite communication, radars, RFID, global positioning systems, etc. Many efforts have been made to manipulate and control polarization by using linear-to-linear or linear-to-circular transmission or reflection polarization converters. Most of the existing linear-to-circular single-layer polarizers have been found to be narrowband. Some attempts have been made to improve the bandwidth of these polarizers including using multiple layered structures at the expense of a bulkier device. There was, however, still a requirement for thin single-layer linear-to-circular polarizers with enhanced bandwidth. The purpose of this research was to design two thin single-layer linear-to-circular polarizers, one for transmission and the other for reflection, with enhanced bandwidth. A thin single-layer linear-to-circular transmission polarizer with a 3 dB axial ratio bandwidth of 34% is presented. The bandwidth of this polarizer is significantly better than that of previously published polarizers of the same type. The unit cell of the polarizer consists of an I-shaped strip and a perpendicular linear strip printed on the one side of a thin dielectric substrate and two additional capacitive coupling strips printed on the other side of the substrate. Experimental results were found to agree well with the simulated results. A thin single-layer reflective linear-to-circular polarizer with a 3 dB axial ratio bandwidth of 57% is also presented. The unit cell of the polarizer consists of an I-shaped strip and a perpendicular linear strip printed on the one side of a substrate and a ground plane on the other side of the substrate. Experimental results for this polarizer were also found to agree well with the simulated results. / Dissertation (MEng)--University of Pretoria, 2018. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted

Page generated in 0.0663 seconds