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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.
1

Design, construction and analysis of a solid state nearly-isotropic light source

Kovacs, Paul 09 December 2016 (has links)
Isotropic radiators are known to be a useful tool across a wide range of applications, from applications in light dosimetry in human/animal tissue to calibration of sensitive laboratory equipment. While the bene ts are known, constructing such a tool has proven to be di cult. Currently, there are no commercially available isotropic or nearly isotropic radiators. Previous attempts at constructing an isotropic radiator have been limited to a 10% isotropy level. This thesis covers the design, construction, and analysis of a nearly isotropic optical light source. The constructed source has extrema anisotropies, over a solid angle of approximately 3 steradians, of +\-3% (with 95% of that solid angle being within +\- 2.5% anisotropy). / Graduate
2

Osvětlovací technika moderních vozidel a měření dohlednosti na koncová světla / The Lighting Equipment Used in Modern Vehicles and the Measurement of the Range of Visibility of the Rear Lights

Belák, Michal Unknown Date (has links)
This work is about lighting equipment of modern vehicles, its historical development, present condition and possibilities of its further progress and measuring of the range of visibility of the rear lights. First part is aimed at lighting equipment used in modern vehicles as a whole. It describes sources of light, their principle, construction, advantages and disadvantages. Next it deals with searchlights and other lighting devices, their gradual development, construction and modern solutions which are used in them, and also their future development. Second part of the work is aimed at characterization of ways of measuring the range of visibility used in practice, their possible application to measuring of the range of visibility of the rear lights and on proposal of presentive methodics for this measurement. Realization and interpretation of practical measurement by this methodics is included.
3

Breaking the Surface

Vice President Research, Office of the January 2008 (has links)
Andrea Damascelli is looking to usher in a new era of quantum computing with a groundbreaking technique that defies all nanotechnology research to date.
4

Métodos para otimização de abertura dinâmica da nova fonte de luz síncrotron brasileira - Sirius / Methods for optmisation of the dynamic aperture of the new Brazilian synchrotron light source

Marcondes, Rafael José França, 1987- 03 August 2012 (has links)
Orientador: Eduardo Granado Monteiro da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-19T18:24:03Z (GMT). No. of bitstreams: 1 Marcondes_RafaelJoseFranca_M.pdf: 4781078 bytes, checksum: 963ca375d793021d73e27eaf311966c2 (MD5) Previous issue date: 2012 / Resumo: Um novo anel de armazenamento de elétrons está sendo projetado para a produção de luz síncrotron de alto brilho no Laboratório Nacional de Luz Síncrotron (LNLS), em Campinas. Para atingir um alto brilho, requer-se uma forte focalização do feixe, levando a fortes não-linearidades dos campos magnéticos, o que limita a região de estabilidade do movimento dos elétrons. Neste trabalho, estudamos a dinâmica destas partículas no anel e aplicamos métodos para a otimização da abertura dinâmica / Abstract: A new electron storage ring, Sirius, is being designed for the production of high brightness synchrotron light at the Brazilian Synchrotron Light Laboratory (LNLS), in Campinas. To achieve high brightness, strong focusing of the beam is required, leading to strong non-linearities in the magnetic elds, which limit the region of stable motion of the electrons. In this work we study the dynamics of these particles in the ring and apply methods for the optimisation of the dynamic aperture / Mestrado / Mestre em Física
5

Design řady LED svítidel / Design of LED lamp set

Slívová, Marta January 2011 (has links)
This master thesis is a design study of LED interior light units. Aim of the study is to design set of three luminaire types – office table light, standard lamp and a pendant luminaire. All three lights are following the same design. Curve is the main shape for this light set. LED, called light source of the future, is supposed to be the only light source at all three units. LEDs were chosen as the contemporary most efficient and modern light source. Use of LEDs has many positive economical and social aspects. Use of innovative design, most recent technologies and modern shapes brings new inspiration and variety into current interior light world. Development of light systems study is mapping light units history from the beginning into presence. It brings interesting look into interior light history.
6

Porovnání výsledků experimentálních měření dohlednosti s dostupným software / Comparison of Results of Experimental Visibility Measurements with Available Software

Ondris, Róbert January 2012 (has links)
Master's thesis evaluates determined values of visibility from the motor vehicle on the pedestrian by reduced visibility distance when using halogen headlights, which are the results of experimental measurements a compare them with theoretical values determined by assistance of available software.
7

Změny spektra zářivého toku světelných zdrojů v závislosti na napětí / Spectram power distribution of radiant flux depending on supply voltage

Novotný, Tomáš January 2008 (has links)
The master’s thesis consists of two parts. The first part describes base quantities of lighting engineering, basics of the electrical energy transformation to the light energy, laws of the thermal radiation and characteristics of incandescence and discharge light sources used for general illumination. This part concludes with a theoretical analysis of influence of power supply on the parameters of light source’s luminous flux. The second part of the thesis deals with the draft and configuration of a workplace for measuring spectral radiation of light sources depending on power supply. The last part of the thesis is created by the evaluation of spectral radiation and other light parameters changes according to the light source’s power supply changes.
8

X-ray studies of zeolites and MOFs

Morris, Samuel Alexander January 2016 (has links)
This thesis is largely a study of the ADOR process (assembly-disassembly-organisation-reassembly) when applied to zeolite UTL. The final chapter of this thesis deals with the adsorption of the medical gases NO and CO onto the metal organic framework NiNaSIP. Chapter 4 is devoted to the disassembly and organisation steps of the ADOR process. Calcined UTL was hydrolysed using 0.1 – 12 M HCl solutions from 75 – 95 °C run over 10 mins to 72 hrs. A three step mechanism is proposed, which is comprised of an initial rapid hydrolysis that removes the majority of the interlayer constituents of UTL, causing the silica-rich layers to largely collapse. This is followed by a slow, temperature and molarity dependent, deintercalation process that sees the remainder of the interlayer material removed resulting in the full collapse of the layers to form IPC-1P. The third step is a temperature and molarity dependent rebuilding process, whereby the interlayer region is slowly rebuilt, eventually forming a precursor which upon calcination becomes IPC-2 (OKO). Chapter 5 uses the pair distribution function (PDF) technique to structurally confirm the intermediate of the ADORable zeolite UTL. The intermediate, IPC-1P, is a disordered layered compound formed by the hydrolysis of UTL in 0.1 M HCl. Its structure is unsolvable by traditional X-ray diffraction techniques. The PDF technique was first benchmarked against high-quality synchrotron Rietveld refinements of IPC-2 (OKO) and IPC-4 (PCR) – two end products of IPC-1P condensation that share very similar structural features. An IPC-1P starting model derived from density functional theory was used for the PDF refinement, which yielded a final fit of Rw = 18% and a geometrically reasonable structure. This confirms that the layers do stay intact throughout the ADOR process, and shows that PDF is a viable technique for layered zeolite structure determination. Chapter 6 examines the reassembly stage by following the in-situ calcination of a variety of hydrolysed intermediates into their three-dimensional counterparts. Beamline I11 at Diamond Light Source provided high-quality PXRD patterns as a function of temperature, which were refined against using sequential Pawley refinements to track the unit cell changes. 0.1, 1.75, 2.5 and 12 M hydrolysed lamellar precursor phases were calcined. The largest unit cell changes were observed for 0.1 M, and the smallest for 12 M. This shows that increasing the molarity must prebuild most of the interlayer connections, such that upon calcination, only minimal condensation occurs to fully connect the layers. Chapter 7 probes the uptake of the medical gases CO and NO into the metal organic framework NiNaSIP. An in-situ single-crystal XRD study was undertaken using an environmental gas cell at beamline 11.3.1 at the Advanced Light Source. NiNaSIP was first dehydrated to reveal an open nickel site, which acted as the main site of adsorption for the inputted gases. NO was observed in a bent geometry at an occupancy of 40 % and a Ni – N bond length of 2.166(16) Å. The oxygen was modelled to be disordered over two sites. CO was not fully observed, as only the carbon was able to be modelled with an occupancy of 31.2 % and a Ni – C bond length of 2.27(3) Å.
9

Desenvolvimento de uma fonte luminosa baseada em lâmpadas halógenas para aplicações na fotobiologia e fotomedicina / Development of a light source based in halogen lamps for applications in the photobiology and photomedicine.

Fonzi, Wagner 15 August 2008 (has links)
Este projeto teve como finalidade construir uma fonte de luz baseada em lâmpadas halógenas que apresentasse características técnicas adequadas para aplicações em fotobiologia e fotomedicina, versátil e comercialmente viável. Foram analisadas as características de diferentes lâmpadas halógenas e realizados os experimentos com duas lâmpadas escolhidas, das quais utilizamos a lâmpada de menor divergência luminosa. Foi analisado também o material do corpo da fonte, com relação a características de aquecimento e peso, sendo escolhido um corpo de alumínio produzido industrialmente. Foram avaliadas as características ópticas das lentes, sendo escolhidas as lentes de vidro utilizadas em retroprojetores. Foram analisados os materiais e a construção de filtros térmicos para diminuir o aquecimento do objeto sob irradiação, sendo que escolhemos construir um filtro térmico próprio, que utiliza a água como absorvedor de calor. Medimos e avaliamos as características: espectrais, térmicas, a potência radiante (irradiância) e sua distribuição espacial de três protótipos, onde cada um recebeu modificações de modo a torná-los mais adequados para aplicações na fotoquimeoterapia. Foram também realizados testes preliminares de fotocitotoxicidade do protótipo final com o composto fotossensibilizador de nome comercial Photogem® aplicado em células tumorais de adenocarcinoma de colo retal humano (HT29), cujo resultado foi a ativação do composto fotossensibilizador e indução da morte celular. / The aim of this work was to produce a light source based in halogen lamps. This source should have appropriated technical characteristic for application in photobiology and photomedicine, it has easy operation and be commercially viable. The characteristics of different halogen lamps were evaluated and the lamp of smaller luminous divergence was chosen. We also have evaluated the material of the source holder, especially heating characteristics and weight; finally we chose an aluminum holder. Then, the lenses optical characteristics were studied, and we decided that the glass lenses used in projectors were the best. The materials and the construction of thermal filters were evaluated in order to reduce the heating of the object under irradiation, and we preferred to construct a thermal filter, that uses water as an heat absorber. The spectral and thermal characteristics, the radiant power (irradiance) and its space distribution of three prototypes were measured and evaluated, each one received modifications to become more appropriated to applications in photochemotherapy. We also made preliminaries tests of photocytotoxicity and the final prototype was used with the photosensitizer (Photogem®) in human colon carcinoma cell lines HT-29, resulting in the photosensitizer activation, that induced cellular death.
10

Avaliação \"in vitro\" da alteração de temperatura intra-câmara  pulpar durante clareamento em consultório empregando fontes de luz / Pulp Chamber temperature rise during light-activated bleaching: an in vitro study

Pangrazio, Eugenio Gabriel Kegler 06 March 2009 (has links)
O clareamento dental é um procedimento que está diretamente relacionado à estética dental e cabe ao profissional de odontologia conhecer e dominar os diferentes materiais, métodos de ativação e técnicas de clareamento. Este estudo ¨In Vitro¨ avaliou comparativamente o aumento de temperatura intra-câmara pulpar durante o clareamento em consultório ativado com diferentes fontes de luz com e sem gel clareador. Foi selecionado 1 incisivo central superior humano, seccionado na porção radicular 3 mm abaixo da junção cemento-esmalte. O canal radicular foi alargado para permitir a introdução do sensor do termômetro dentro da câmara pulpar. A câmara pulpar foi preenchida com uma pasta térmica (C.N.P.J. 52.891. 405/0001-60, Implastec Electroquímica, Votorantim, SP), a fim de permitir a transferência de calor das paredes dentárias para o sensor de um termômetro digital com termopar tipo K (MT- 401A) durante o clareamento. A porção radicular do dente foi submersa em água a 37º C elevando a câmara pulpar a mesma temperatura. Um agente clareador fotossensível à base de peróxido de hidrogênio a 35% (Lase Peroxide DMC Equipamentos) foi utilizado. Para a ativação do gel foram empregados quatro aparelhos com diferentes fontes de luz: luz halógena (Spectrum Dentsply); luz híbrida à base de LED e Laser Diodo (Ultra Blue IV DMC Equipamentos); LED (Smart Lite PS Dentsply) e LED verde (D Light Green - Kondortech). As ativações foram feitas de acordo com as especificações do fabricante. com seis aplicações para cada grupo. Os resultados foram submetidos a ANOVA a dois critérios e teste de Tukey (p 0,05). Os grupos estudados e as medias do aumento da temperatura foram: D - Light Green sem gel (37ºC) A, D - Light Green com gel (37,17ºC) A, Smart Lite sem gel (39,17ºC) C, Smart Lite com gel (40ºC) D, Ultra Blue IV sem laser sem gel (38ºC) B, Ultra Blue IV sem laser com gel (39,17ºC) C, Ultra Blue IV com laser sem gel (38, 17ºC) B, Ultra Blue IV com laser com gel (39,33ºC) C, Spectrum sem gel (39,17ºC) C e Spectrum com gel (40,83ºC) E. Todas as lâmpadas apresentaram aumento da temperatura intracâmara pulpar, com exceção do D - Green Light, sem atingir a temperatura crítica de 5,5ºC. A fonte de luz halógena com gel apresentou o maior aumento de temperatura. / The purpose of this In Vitro study was to measure the intrapulpal temperature rise induced by various light sources and a bleaching gel. The root portion of an intact human maxillary central incisor was sectioned with a diamond disk 3 mm below the cement enamel junction. The apical foramen of the root was enlarged and remaining pulp tissue was removed. The empty pulp chamber was filled with a heat sink compound and a thin K-type thermocouple was introduced into the pulp chamber. The root surface of the tooth was partially submerged in a water bath during the testing procedure at 37°C elevating the pulp chamber at the same temperature. A 35% hydrogen peroxide bleaching gel (Lase Peroxide - DMC Equipamentos) containing heat enhanced colorants was applied to the vestibular tooth surface. Light units used were a conventional tungsten quartz halogen (Spectrum Dentsply), a LED/Laser device (Ultra Blue IV DMC Equipamentos), a high intensity LED (Smart Lite PS Dentsply) and a green LED light (D Light Green - Kondortech). A pilot study and a statistical analysis were made to determine the number of application needed. Six applications were made for each system and gel combination. Differences between the starting temperature and final temperature reading were taken and the calculated temperature changes were averaged to determine the mean value in temperature rise. Temperature rise values were compared using two-way analysis of variance (ANOVA) at a preset alfa of 0.05. Temperature rise varied significantly depending on the type of light used and in presence or absent of bleaching gel. The conventional tungsten quartz halogen lamp with bleaching gel induced significantly higher temperature increases than any other curing unit (3,83°C). The green light-emitting diode unit without gel produced no temperature changes. Almost as a rule, the presence of bleaching gel resulted in a significant intrapulpal temperature increase (approximately 1ºC) over that reached using no gel. However, light bleaching systems thus increase intrapulpal temperature, all the procedures used in this study were below the critical level of 5,5ºC.

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