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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.
111

Studium vlivu magnetických polí na biologické tkáně / Study of the influence of magnetic fields on biological tissue

Vlachová Hutová, Eliška January 2012 (has links)
The aim of this research is to explore the influence of magnetic field on early somatic embryos (ESEs) of spruce and pine. The magnetic field is gradual. This is important for the experiment, each cluster of ESE was exposed to magnetic field of different intensity. The resulting report of this experiment consists of the comparison between various methods of image analysis and the difference in growth of ESEs due to different exposure to magnetic field and surrounding temperature. Enclosed is a proposal of ESE size computing algorithm from a given image.
112

Analýza fotovoltaických článků pomocí fotoluminiscence / Analyse of photovoltaic solar cells by the photoluminescence method

Richter, Vladimír January 2014 (has links)
This diploma thesis deals with the issues of photovoltaic cells. The main aim of this thesis is to introduce the principles of operation of solar cells and methods of detection of defects affecting their quality. The first part is about the functional properties of silicon cells and it also examines the possibilities of detecting the defects of these structures. It also describes the most commonly used modern diagnostic methods. In the next part, practical tests of photovoltaic cells using the methods electroluminescence and photoluminescence are performed. These methods are based on the excitation of luminescence radiation of the silicon material by the external light source.
113

Kalibrace snímačů pro multispektrální datovou fúzi v mobilní robotice / Sensor Calibration for Multispectral Data Fusion in Mobile Robotics

Kalvodová, Petra January 2015 (has links)
Thesis deals with data fusion and calibration of sensory system of Orpheus-X3 robot and EnvMap mapping robot. These robots are parts of Cassandra robotic system that is used for exploration of hazardous or inaccessible areas. Corrections of measured distances are determined for used laser scanners Velodyne HDL-64, Velodyne HDL-32 and range camera SwissRanger SR4000. Software MultiSensCalib has been created and is described. This software is used for determination of intrinsic parameters of heterogeneous cameras of the sensory head and for determination of mutual position and orientation of these sensors. Algorithm for data fusion of CCD camera stereo pair, thermal imager stereo pair and range camera is proposed. Achieved calibration and data-fusion parameters are evaluated by several experiments.
114

The Effects of Parkinson's on Fixational Stability

Mallahan, Erin L. 01 January 2005 (has links)
Parkinson's disease (PD) is a progressive, neurological movement disorder. The stability of eye movements in PD is not well understood but many patients report difficulty doing tasks that require stabilized fixation and gaze. The ability to stabilize an image on the retina is critical is acquiring visual information. The purpose of this study was to compare the stability of fixational eye movements of PD patients to those of age-matched controls. Eye movements during simple fixation tasks were recorded from 66 subjects (ages 52 to 84), and 36 age-matched controls (ages 58-85). The absolute velocity of the fixational eye movements were recorded and correlated to a clinical measure of disease progression as measured by the Unified Parkinson's Disease Rating Scale (UPDRS). Unstable, non-rhythmic eye movements were seen in the PD patients. There were significant differences in the absolute velocity and standard deviation between the control group and the PD group in both the horizontal and vertical directions. The correlation of the absolute velocity to the UPDRS was not significant. Parkinson's disease does appear to affect the stability of eye movements. The instabilities in the eye movements appear to precede body tremor. This could lead to an early method for diagnosis and analysis of the disease.
115

Développement et étude d'un viscosimètre absolu à chute de bille

Brizard, Matthieu 20 May 2005 (has links) (PDF)
L'augmentation de l'incertitude tout au long de l'échelle de viscosité étant le principal inconvénient de la viscosimétrie capillaire, un viscosimètre absolu à chute de bille a été développé, qui permet de couvrir une large gamme de viscosité tout en gardant une faible incertitude. La mesure de viscosité repose alors sur la mesure de la vitesse limite de chute de la bille. Un banc expérimental a été développé afin d'atteindre une incertitude relative de l'ordre de 10-3. Il permet d'observer la trajectoire de la bille à l'intérieur d'un tube cylindrique rempli du liquide étudié et d'obtenir l'évolution de la vitesse. La caractérisation métrologique de ce banc expérimental est présentée en utilisant tout d'abord la loi de propagation des incertitudes et ensuite la simulation numérique de Monte-Carlo. Enfin, les mesures de viscosité et les incertitudes obtenues avec le viscosimètre à chute de bille sont confrontées à celles obtenues avec un viscosimètre capillaire.
116

Development of a gamma-ray beam profile monitor for the high-intensity gamma-ray source

Regier, Thomas Zachary 29 October 2003
Beam profile monitors provide position and ux distribution information to facilitate the configuration of an experimental apparatus and are an important component of any accelerator facilities beam diagnostic system. Nuclear physics experiments typically involve the incidence of high energy particles or gamma-rays on some target material and the detection of the products of the ensuing interactions. Therefore, knowing the profile of the incident radiation beam is desirable. To address the need for a profile monitor for the High-Intensity Gamma-Ray Source, development of a CCD-based gamma-ray beam profiler was undertaken. The profiler consisted of plastic scintillator, a lens system and a Starlight Express MX5 CCD camera, all contained within a light tight box. The scintillation pattern, created by the interaction between the incident gamma-rays and the scintillator, could be focused onto the CCD. Simulations were used to determine the amount of power that would be absorbed for different beam energies and scintillator thicknesses. The use of a converter material, placed directly against the scintillator to improve power deposition, was also investigated. The system was tested in order to and the camera noise characteristics, the optical resolution and magnification and the systems responsivity to power absorption in the scintillator. Using a 137Cs source, preliminary beam proles were obtained. By combining the results of the testing and simulation, predictions of the required length of exposure were made. It was determined that a beam with a flux of 10^6/s and a diameter of 2.5 cm could be profiled, using 6.0 mm of plastic scintillator and 0.6 mm of iron converter, to within 5% error per 0.64 mm x 0.91 mm resolving unit, in less than 1 minute.
117

Development of a gamma-ray beam profile monitor for the high-intensity gamma-ray source

Regier, Thomas Zachary 29 October 2003 (has links)
Beam profile monitors provide position and ux distribution information to facilitate the configuration of an experimental apparatus and are an important component of any accelerator facilities beam diagnostic system. Nuclear physics experiments typically involve the incidence of high energy particles or gamma-rays on some target material and the detection of the products of the ensuing interactions. Therefore, knowing the profile of the incident radiation beam is desirable. To address the need for a profile monitor for the High-Intensity Gamma-Ray Source, development of a CCD-based gamma-ray beam profiler was undertaken. The profiler consisted of plastic scintillator, a lens system and a Starlight Express MX5 CCD camera, all contained within a light tight box. The scintillation pattern, created by the interaction between the incident gamma-rays and the scintillator, could be focused onto the CCD. Simulations were used to determine the amount of power that would be absorbed for different beam energies and scintillator thicknesses. The use of a converter material, placed directly against the scintillator to improve power deposition, was also investigated. The system was tested in order to and the camera noise characteristics, the optical resolution and magnification and the systems responsivity to power absorption in the scintillator. Using a 137Cs source, preliminary beam proles were obtained. By combining the results of the testing and simulation, predictions of the required length of exposure were made. It was determined that a beam with a flux of 10^6/s and a diameter of 2.5 cm could be profiled, using 6.0 mm of plastic scintillator and 0.6 mm of iron converter, to within 5% error per 0.64 mm x 0.91 mm resolving unit, in less than 1 minute.
118

Development of a Handheld Night Vision System

Karp, Jonas, Ek, Robert January 2009 (has links)
The task for this master thesis was to create a specification for a second prototype of Scandilumen´s handheld gated night vision system. Current prototype is analogue and is to be upgraded with a digital interface. The specification was to contain information about manufacturers and performance on critical components such as image intensifier tube, image sensor and display. Scandilumen have previous experience with CCD cameras and wanted to know if the CMOS technology were sensitive enough to work properly in gated systems where high sensitivity is critical. Different image processing techniques was analyzed to find out the possibility to enhance image quality with an FPGA built-in into the system. When the specification is implemented, Scandilumen will have a prototype up-to-date with a digital interface and real time image enhancement. / Uppdraget i denna magisteruppsats var att ta fram en specifikation för en andra prototyp av Scandilumens grindade mörkerkamera. Nuvarande prototyp är analog och skall uppgraderas till en digital variant med display och anslutningsmöjlighet till dator. Specifikationen skall innehålla uppgifter om vilka ingående komponenter som skall användas samt vilken prestanda de skall ha. Exempel på dessa komponenter är bildförstärkarrör, bildsensor och displayer. Stor vikt har lagts vid att avgöra vilken typ av bildsensor som skall ingå i systemet. Scandilumen har tidigare erfarenhet av CCD-kameror men ville undersöka om CMOS-tekniken var känslig nog för denna typ av applikation. En jämförelse gjordes mellan de olika teknikerna med fokus på de höga krav som ställs på känslighet. Dessutom analyserades olika typer av bildbehandling som är lämpliga för systemet och som också går att implementera i en FPGA på lämpligt sätt. Om specifikationen följs kommer Scandilumen ha en prototyp uppdaterad med ett digitalt format och den senaste tekniken.
119

Optical Design of Beam Shaping Optics for Camera Probe and LED Light Illumination Used for Minimally Invasive Abdominal Surgery

He, Weiyi 02 November 2010 (has links)
The optical design of a LED illuminator and camera imaging system were studied for potential use in a small medical "robotic type" probe to be used for minimally invasive abdominal surgery. Beam shaping optical reflectors were studied to increase the intensity distribution of the LED beam directed toward a close-by target surface. A CMOS/CCD camera and lens was used to image the targeted area. In addition, extensive optical ray tracing simulations were made to predict the intensity patterns. The experimental measurements and ray tracing simulations were in good agreement, and indicated that 20 degree cone reflectors for the LED sources and appropriate micro-lens/CCD chip imaging optics should provide a useful image at a working distance of about 5 cm.
120

Cenozoic history of North Atlantic deep sea carbonate preservation

Länje, Marcus January 2015 (has links)
Carbonate preservation in the oceans occurs at a depth called the carbonate compensation depth (CCD). The CCD is where the input rate of carbonate from the surface of the ocean is balanced by the dissolution rate. Factors controlling the CCD are the CO2 in the atmosphere, weathering, and productivity in the surface water, the depth of the lysocline and deep water currents (and their ocean circulation). Two previous studies have investigated the variation of the CCD through geologic time, one in the equatorial Pacific (Pälike et al., 2012) and the other compiled results from the Pacific, Atlantic and Indian Oceans (Van Andel, 1975). The project consisted of compiling a database of sediment lithologies for many more sites in the Atlantic since the compilation by Van Andel, 1975, and together with a subsidence model of the ocean crust the systematic variations of CCD could be investigated. The results show that the CCD varies both spatially and temporally in accordance with previous studies. The reconstruction of the CCD needs further analysis, and possibly data from the oldest drilling program, the Deep Sea Drilling Project (DSDP). One result that is very important is that this study includes a total of 91 sites in the Atlantic Ocean, far more than in any of the other two studies. Future work can build upon the already started database of sediment lithologies.

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