Dissertations / Theses on the topic 'Ultraviolet'

Orientadores: Priscila Gava Mazzola, Patrícia Moriel
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Filtros solares são moléculas com capacidade de absorver e/ou refletir a radiação UVA e UVB, evitando assim que esta radiação alcance a epiderme ou até mesmo a derme, porém alguns filtros podem apresentar instabilidade quando absorvem a radiação, com consequente perda desta função. A fotoinstabilidade após a exposição à radiação UV é bem conhecida e descrita, porém não existem muitos dados relacionando a estabilidade destes filtros após a irradiação de luz fluorescente emitida pelas lâmpadas comerciais presentes em lares e escritórios. O presente estudo propõe avaliar a fotoestabilidade de produtos comerciais com FPS 30, após irradiação UV e também após a irradiação fluorescente, correlacionando o comportamento de cada produto frente aos diferentes tipos de radiação. A metodologia aplicada é in vitro, sendo que os produtos testados foram aplicados em duas diferentes placas de polimetilmetacrilato Polimetil metacrilato (PMMA) e irradiados por um simulador solar com filtros específicos para UVA/B e por uma fonte de luz fluorescente comercial. De acordo com os resultados obtidos, foi observado que a placa de PMMA utilizada pode influenciar nos resultados e todas as amostras testadas apresentaram um comportamento fotoestável quando expostos à radiação ultravioleta ou fluorescente, ou seja, não apresentaram redução na sua capacidade de absorção da radiação UVA/B mesmo após doses de radiação bem elevadas. Estes resultados demonstram que as amostras testadas apresentaram um comportamento bastante estável em diversas situações em que a população está exposta no dia a dia
Abstract: Sunscreens are molecules with ability to absorb and/or reflect the UVA and UVB radiation, thereby preventing radiation that reaches the epidermis or dermis even though some filters can be unstable when they absorb radiation, with consequent loss of its function. The photostability after exposure to UV radiation is well known and described, but there are not many data correlating the stability of these filters after fluorescent light irradiation, emitted by commercial lamps present in homes and offices. This study proposes to assess the photostability of commercial products SPF 30 after artificial UV irradiation and also after the fluorescent radiation, correlating the behavior of each product against different types of radiation. The methodology applied was in vitro, and the products tested were applied on two different plates of polymethyl methacrylate (PMMA) and irradiated by a solar simulator with specific filters for UVA/B and a fluorescent light source commercial. According to the results, the plate can play an important role in the photostability data and all samples tested presented a similar photostable behavior when exposed to UV or fluorescent light, or showed no reduction in its capacity for absorption of UVA/B even after higher doses of radiation. These results demonstrate that the samples tested presented a very stable behavior in various situations in which the population is exposed on a daily basis
Mestrado
Ciencias Biomedicas
Mestre em Ciências Médicas

Die vorliegende Arbeit befasst sich mit der Untersuchung von Metall-Halbleiter-Metall ultravioletten Photodioden basierend auf Dünnschichten der weitbandlückigen Halbleitern Magnesiumzinkoxid (Mg,Zn)O und Galliumindiumoxid (In,Ga)2O3. Die Arbeit behandelt zwei inhaltliche Schwerpunkte. Der erste Schwerpunkt liegt auf Herstellung, Entwicklung und Charakterisierung der wellenlängenselektiven (Mg,Zn)O-Photodioden bei Erhaltung der Wurtzitstruktur in UVA und UVB Spektralbereichen. Dabei wurde eine integrierte optische Filterschicht mit einem höheren Mg-Gehalt verwendet, die einen Teil der von der Rückseite einfallende Strahlung absorbieren kann. Um die Selektivität der Absorptionskante und die Bandbreite des Detektoren abzustimmen, wurden unterschiedliche Kombinationen der Mg-Gehalte in den Schichten untersucht. Weiterhin wurde der Ansatz eines kontinuierlichen Kompositionsgradienten mittels großflächig gepulster Laserabscheidung genutzt, um monolithisch mehrkanalig schmalbandige Photodioden zu realisieren. Dadurch konnten die kontinuierliche Verschiebung der Absorptionskante von beiden Activ- und Filterschichten sowie die Photodetektion mit minimierter und einheitlicher spektraler Auflösung innerhalb von einem 2 inch im Durchmesser Wafer ermöglicht werden. Der zweite Schwerpunkt konzentriert sich auf die Untersuchung der wellenlängenselektiven Photodioden basierend auf Si-dotierten (In,Ga)2O3 Dünnschichten mittels der kontinuierlichen Kompositionsgradienten durch unterschiedliche Variation des Indium-Gehaltes. Die Absorptionskante der (In,Ga)2O3 Dünnschichten konnte von UVA bis zum UVC Spektralbereich abgestimmt werden. Die chemische und strukturelle Eigenschaften der Dünnschichten wurden mittels Kathodolumineszenzmikroskop, energiedispersive Röntgenspektroskopie and Röntgenbeugung studiert. Die elektrischen Eigenschaften der Schottky-Kontakte wurden mit hochpräzisen Strom-Spannungs-Messung bestimmt. Die Untersuchung der Absorptionskante sowie der Effzienz der Photodioden geschieht mittels spektralaufgelöster Photostrommessungen.

Pour répondre à la demande croissante des utilisateurs du rayonnement ultraviolet, le BNM-INM a entrepris la réalisation d'une échelle d'éclairement énergétique spectrique dans le proche ultraviolet (200-400 nm) basée sur l'utilisation des radiomètres étalons. Un radiomètre est constitué par trois éléments essentiels, un détecteur optique de sensibilité connue, un filtre interéférentiel à bande étroite et un diaphragme d'une surface determinée. La caractérisation de nouvelles photodiodes à large cap et de filtre interéférentiels montre qu'il est possible de réaliser des radiomètres à filtre étalons à bande spetrale étroite de 10 à 20 nm de largeur régulièrement réparties entre 200 et 400 nm. L'utilisation de ces radiomètres permet d'étudier le spectre des sources de rayonnement émettant dans l'ultraviolet et d'améliorer leur étalonnage en éclairement. Ce travail présente d'abord les études accomplies pour sélectionner les meilleurs éléments pour la réalisation des radiomètres à filtre dans le proche ultraviolet, ensuite la réalisation des radiomètres complets et leur étalonnage par rapport au radiomètre cryogénique
To satisfy the requirements of ultraviolet radiation user, the BNM-INM has undertaken the realization of irradiance scale in the bear ultraviolet (200-400 nm) bases on the use of standard radiometers. A radiometer is composed by tree main components, an optical detector of known responsivity, a narrow band interference filter and an aperture of identified surface. The charactization of new wide-band gap photodiodes and of interference filters shows that it is possible to realize narrow spetral band filter radiometres of 10 to 20 nm of width regularly distributed between 200 and 400 nm. The use of these radiometers allows studying the spectrum of ultraviolet sources sources and also omprving their irradiance calibration. Firstly, this work presents acomplished studies carried out to select the best elements for realizing near ultraviolet filter radiometers ; then, it presents the realization and the characterization of completed filter radiometers and their calibration against cryogenic radiometer

Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, December 2005.
Thesis Advisor(s): Richard C. Olsen, Christopher Brophy. Includes bibliographical references (p.55-56). Also available online.

The recent development of extreme ultraviolet (EUV) sources has increased the need for diagnostic tools, and has opened up a previously limited portion of the spectrum. With ultrafast laser systems and spectroscopy moving into shorter timescales and wavelengths, the need for nanosecond scale imaging of EUV is increasing. EUV's high absorption has limited the number of imaging options due to the many atomic resonances in this spectrum. Currently EUV is imaged with photodiodes and X-ray CCDs. However photodiodes are limited in that they can only resolve intensity with respect to time and X-ray CCDs are limited to temporal resolution in the microsecond range. This work shows a novel approach to imaging EUV light over a nanosecond time scale, by using an EUV scintillator to convert EUV to visible light imaged by a conventional streak camera. A laser produced plasma, using a mass-limited tin based target, provided EUV light which was imaged by a grazing incidence flat field spectrometer onto a Ce:YAG scintillator. The EUV spectrum (5 nm-20 nm) provided by the spectrometer is filter by a zirconium filter and then converted by the scintillator to visible light (550 nm) which can then be imaged with conventional optics. Visible light was imaged by an electron image tube based streak camera. The streak camera converts the visible light image to an electron image using a photocathode, and sweeps the image across a recording medium. The streak camera also provides amplification and gating of the image by the means of a micro channel plate, within the image tube, to compensate for low EUV intensities. The system provides 42 ns streaked images of light with a temporal resolution of 440 ps at a repetition rate of 1 Hz. Upon calibration the EUV streak camera developed in this work will be used in future EUV development.
ID: 029049655; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.E.E.)--University of Central Florida, 2010.; Includes bibliographical references (p. 73-76).
M.S.E.E.
Masters
School of Electrical Engineering and Computer Science
Engineering and Computer Science

The thesis concerns experimental studies of discharge excited lasers operating in the vacuum ultraviolet (VUV) region of the spectrum. The known molecular fluorine laser operating at 157nm, on a bound- to-bound transition of the F₂ molecule was selected for initial study. As a result of the work reported here the energy per pulse was increased by a factor of five (10mJ to 50mJ) from that of earlier F₂ lasers. Similary the working lifetime of the gas mixture was increased from a few shots to several thousand by the application of cryogenic gas purification techniques. These improvements have resulted in the development of a practical commercial F₂ laser. The performance characteristics of the fluorine laser and their relationship to the physical mechanisms are discussed. With the objective of achieving laser action in the 110 to 130nm region of the VUV a novel scheme is investigated. The scheme involves the production of a population inversion between the v'=1 level of the b¹π_u state of molecular nitrogen and high lying levels of the X¹Σ_g ground state. The excitation of the upper laser level involves production of N₂ molecules in the a¹π_g state by means of a pulsed discharge. Transfer of population from this intermediate 'a' state to the upper level is accomplished by absorption of radiation at 308nm from a discharge excited xenon chloride laser. The practicality of this scheme has been investigated to the extent that populations of the order of 10¹³ molecules per cm³ have been produced in the 'a' state and laser induced fluorescence on the 'b' to 'X' band has been observed. Under the conditions of "the present experiments the potential VUV gain is too small (10^-4cm^{-1>/sup>) to reach laser threshold. The problems of increasing the gain to reach threshold for a practical device are discussed.}

The aim of our study was to establish a >model imitating of UV-B (wavelength peak is 311 nm) therapy for rat’s skin and to find match macroscopical and following histological skin changes including melanocytes spreading and melanin distribution.

The LINEATE IMAGING NEAR ULTRAVIOLET SPECTROMETER (LINUS) instrument has been used to remotely detect and measure sulfur dioxide (SO2). The sensor was calibrated in the lab, with curves of growth created for the 0.29 0.31 æ - spectral range of the LINUS sensor. Field observations were made of a coal burning plant in St. Johnâ s, Arizona at a range of 537 m. The Salt River Coronado plant stacks were emitting on average about 100 ppm and 200 ppm from the left and right stacks respectively. Analysis of the LINUS data matched those values within a few percent. Possible uses for this technology include remote verification of industry emissions and detection of unreported SO2 sources.

Ultraviolet radiation (UVR) is a by-product of the welding process and is emitted by the arc formed between the electrode and the base metal. Exposure to UVR can produce acute and chronic effects on the eyes and skin, including photokeratitis and erythema (acute), and pterygium and skin cancer (chronic). The measurement of UVR can be used to determine the level of hazard posed by a particular source. The personal UVR exposure levels of a group of welders and nearby workers was estimated using a photosensitive polymer film, polysulphone. The polysulphone film was attached to eye protection, the workers clothing and also placed throughout the workarea. The estimated ocular exposures of all subjects were found to exceed the eight-hour maximum permissible exposure limit. As the main UVR protective measure for welders is a welding helmet, the degree of protection afforded by a range of helmets was investigated in a laboratory experiment. Radiation was found to be reflected off the filter and toward the eye after entering through: (1) an opening between the edge of the shield and the side of the face, and (2) an opening between the top lip of the shield and the top of the head. The results of this study suggest that welders require ocular protection in addition to welding helmets, and that all exposed skin surfaces of workers in a welding environment should also be protected.

The emission in the ultraviolet domain contains precious information about the supernova (SN) explosion: it is highly sensitive to the metallicity of the SN ejecta; it gives indications on the SN progenitor structure and on how it exploded; UV photons are produced during the interaction with the SN circumstellar material, revealing the environment structure and thus the precursor pre-explosion activity. For these reasons, the Thesis aims mainly to study the properties of SNe in the UV. In particular, it is focused on the analysis of new observations collected with Swift and GALEX satellites, which improve our current poor knowledge of the properties of the different SN Types in this wavelength range. Considering that the forthcoming high-redshift SN surveys will be conducted in the optical and IR ranges, which samples the UV rest-frame emission of the SN, the knowledge of the UV spectral evolution of the local SNe is essential to properly exploit the surveys outputs. Despite the wide interest, to date the sample of SN spectroscopically observed in the UV is still small. With this Thesis we remarkably increased the number of SNe observed in the UV. After a general overview on our current understanding of SNe and their UV emission, we will present for the first time the entire Swift archive of SN spectroscopic observations, obtained during the first two years of observations (2005--2006). The Swift sample includes 9 SNe, specifically 6 SNe Type Ia (SNe 2005am, 2005cf, 2005df, 2005ke, 2005hk and 2006X), 2 Type II (SNe 2005cs and 2006bp) and 1 Type Ib/c (SN 2006jc), collecting 31 UV-grism and 22 V-grism spectra. The limited S/N of the data has been improved by applying an optimized extraction technique and the offset in the zero point of the wavelength calibration removed through the comparison with quasi-simultaneous ground-based spectra. An important step toward the characterization of SNe in the Ultraviolet has been achieved with this work. Indeed, with SN 2005cf, we obtained the best UV spectral follow-up to date for a Type Ia SN, with 7 UV spectra collected during the pre-maximum phases, which improves the past exceptional performance of IUE. In general, the UV spectra of SNe Ia, though to originate predominantly from reverse fluorescence in iron group ions present in the ejecta outermost layers, are found to be characterized mainly by two broad absorptions at about 3050 A and 3250 A [due to Fe, Co, Cr and Ti lines, Kirshner92A, sauer08]. A comparison of the Swift SN Ia spectra with those in literature of SNe 1992A and 1990N shows that SNe Ia with similar optical properties may have different UV behaviour. SN 2006jc, the only Type Ib/c SN in our spectroscopic sample, shows two strong and broad UV emissions at ~2800-3000A, unusual at early epochs and that can be interpreted as a signature of the interaction between the SN ejecta and gas originally ejected by the stellar progenitor. The UV spectra of both Type IIP SNe 2005cs and 2006bp are found to be shaped by blends of singly ionized iron-peak elements lines (mostly FeII, NiII) and MgII, yielding a line blanketing effect, which increases with decreasing temperature. From the comparison of the first 2-years of \swift\ observations to the 15-year IUE activity on Sne, the large number of observations that Swift already collected stands out, as does its great flexibility and rapid reaction time that allow the prompt start of the observational campaigns after the SN discovery and its systematic follow-up. In the second part of the Thesis, the analysis will be focused on the very interesting SN 2005ay, a Type II SN in NGC 3938 of the Plateau subclass. SN 2005ay has been the first target observed within a wide observational program for the multiwavelength study of CC SNe. We will present and analyze the UV spectra of SN 2005ay taken with GALEX (at 4 spectroscopic epochs), as well as the huge amount of spectroscopic and photometric data (107 Optical + 19 NIR photometric epochs and 20 optical spectra) obtained in the Optical-NIR range with 11 different ground-based telescopes. Such extended wavelength sampling, together with the detailed time follow-up, makes SN 2005ay a SN with one of the best coverages ever (after only SN 1987A). For this reason SN 2005ay is going to become a "golden template", for Type II SNe, specifically for SN II-Plateau. With this Thesis, we give a great contribution to the enlargement SN Type II Plateau sample. In fact, despite SNe IIP represent the largest fraction of SN II, only two objects in literature had sufficient data to describe their evolution: SNe 1999em and 1987A. Considering the very peculiar behaviour of the latter, adding SNe 2005ay and 2005cs we actually triple the number of typical SNe IIP observed in the UV with good quality data. The comparative study of the SN IIP sample shows a remarkable similarity among these objects, which, if confirmed by additional SNe II-P, would indicate the cosmological use of II-P SNe as a promising prospect. Finally, as last contribution of this Thesis we will compare the spectral energy distributions (in the range 2000-10000 A) of the main SN Types, discussing the importance of the strong difference between the UV emissions of Type Ia and CC SNe for the possible future use of the photometry as a reliable instrument to classify SNe at very high redshifts.
Lo studio dell'emissione nella banda Ultravioletta di una Supernova permette di ottenere preziose informazioni circa l'evento stesso: essa e' molto sensibile alla metallicita' dell'ejecta della SN; fornisce indicazioni sulla struttura del progenitore e su come esso sia esploso; fotoni UV sono prodotti durante l'interazione con il materiale circumstellare presente attorno alla SN, rivelando la struttura dell'ambiente circostante e quindi le fasi evolutive del progenitore precedenti all'esplosione. Per queste ragioni, la Tesi e' principalmente indirizzata allo studio delle proprieta' UV delle SNe. In particolare, essa e' focalizzata sull'analisi delle nuove osservazioni ottenute con i satelliti Swift e GALEX, migliorando l'attuale scarsa conoscenza delle proprieta' dei diversi tipi di SNe in questo specifico intervallo di lunghezze d'onda. Considerando che le imminenti surveys di SNe ad alto redshift saranno condotte utilizzando le bande ottiche e infrarosse, che campionano in realta' l'emissione UV della SN nel suo sistema a riposo, la comprensione dell'evoluzione spettrale nell'UV delle SN locali e' essenziale per interpretare correttamente i risultati delle stesse surveys. Nonostante l'ampio interesse, tutt'oggi il campione di SNe osservate spettroscopicamente nell'UV e' ancora molto ristretto. Dopo una panoramica generale sulla comprensione attuale del fenomeno SN e delle loro emissioni nell'UV, presenteremo per la prima volta l'intero dataset di osservazioni spettroscopiche di SNe, ottenuto con Swift duranti i primi due anni di attivita' (2005-2006). Il campione di SNe conta 9 oggetti, di cui 6 SNe Tipo Ia (SNe 2005am, 2005cf, 2005df, 2005ke, 2005hk e 2006X), 2 Tipo II (SNe 2005cs e 2006bp) e 1 Tipo Ib/c (SN 2006jc), per un totale di 31 spettri ottenuti con il grism UV e 22 con quello V. Il basso rapporto segnale-rumore che caratterizza i dati e' stato migliorato grazie all'applicazione di una tecnica di estrazione ottimizzata e il problema dello spostamento del punto zero della calibrazione in lunghezza d'onda risolto con il confronto con gli spettri quasi-simultanei ottenuti da telescopi terrestri. Un importante passo verso la caratterizzazione delle SNe nell'UV e' stato compiuto con questo lavoro. Infatti, con SN 2005cf, presentiamo il miglior follow-up UV finora ottenuto per una SN Ia, con 7 spettri UV presi durante le fasi precedenti al massimo, migliorando la precedente gia' eccezionale performance di IUE. In generale, gli spettri UV delle SNe Ia, formati principalmente dal processo di reverse fluorescence negli ioni dei metalli presenti negli strati piu' esterni dell'ejecta, presentano principalmente due assorbimenti larghi a circa 3050 A e 3250 A [dovuti alle righe del Fe, Co, Cr e Ti, Kirshner92A, sauer08]. Un confronto fra gli spettri Swift di SNe Ia e quelli presenti in letteratura delle SNe 1992A e 1990N mostra che le SNe Ia con propriet\`a simili nell'ottico possono differire nell'UV. SN 2006jc, l'unica SN Ib/c del nostro campione spettroscopico, presenta due forti emissioni, rare nelle fasi iniziali, a ~2800-3000 A, che possono essere interpretate come il segno dell'interazione fra l'ejecta della SN e il gas originariamente espulso dalla stella progenitrice. Gli spettri UV di entrambe le SNe IIP, SN 2005cs e SN 2006bp, sono modellati dal "blend" delle righe dei metalli ionizzati (come FeII e NiII) e del MgII, producendo un effetto di "line blanketing" che aumenta con l'abbassarsi della temperatura. Dal confronto delle osservazioni di SNe ottenute con Swift durante i suoi primi due anni e quelle dei 15 anni di attivita' di IUE, l'elevato numero di spettri UV gia' ottenuto con Swift si evidenzia, come anche la sua grande flessibilita' e il suo rapido tempo di risposta che permettono l'avvio della campagna osservativa immediatamente dopo la scoperta ed un'elevata frequenza di osservazioni dello stesso target. Nella seconda parte della Tesi, l'analisi e' focalizzata sull'interessante SN 2005ay, una SN Tipo II esplosa in NGC 3938, appartenente alla sottoclasse delle II Plateau. SN 2005ay e' stato il primo target osservato all'interno di un vasto progetto di osservazione di CC SNe in un ampio intervallo spettrale. Presenteremo e analizzeremo gli spettri UV di SN 2005ay ottenuti con GALEX (a 4 epoche spettroscopiche), insieme all'enorme dataset spettroscopico e fotometrico (126 notti di fotometria e 20 spettri ottici) collezionato nell'ottico e vicino infrarosso presso 11 diversi telescopi. L'estensione in lunghezza d'onda del campionamento e il dettagliato follow-up temporale fa di SN 2005ay una delle SNe con la miglior copertura mai ottenuta (seconda solo a SN 1987A). Per questa ragione, SN 2005ay diventera' un "golden template" per le SNe di Tipo II, specialmente per le Tipo IIP.\\ Con questa Tesi, abbiamo contribuito all'aumento del campione di SNe IIP osservate nell'UV. Infatti, nonostante rappresentino la frazione maggiore di SN Tipo II, solemente due sono gli oggetti in letteratura osservati nell'UV: SN 1999em e SN 1987A. Considerando la peculiarita' di quest'ultima, in pratica aggiungendo SNe 2005ay e 2005cs al campione abbiamo triplicato il numero di SN IIP tipiche con dati UV di buona qualita'. Lo studio comparativo delle SNe IIP nell'UV ha rivelato una notevole somiglianza fra gli oggetti di questa classe, che, se confermata dall'osservazione futura di ulteriori SN IIP, potrebbe confermare l'attendibilita' di queste SNe come indicatori di distanza. In conclusione, come contributo finale di questa Tesi, abbiamo confrontato la distribuzione spettrale di energia (nell'intervallo 2000-10,000 A) dei principali tipi di SNe, discutendo l'importanza che la grande differenza di emissione nell'UV fra SNe Ia e CC puo' avere nel futuro possibile uso della sola fotometria come strumento attendibile per la classifizione delle SNe a redshift molto alti.

Ce travail concerne l'étude et la caractérisation d'une source de rayonnement Extrême Ultraviolet (EUV) pouvant répondre à diverses applications scientifiques et industrielles en particulier celles liées à la nouvelle génération de la lithographie EUV. Cette source pulsée nommée CAPELLA consiste en une décharge dans un capillaire en alumine où circule un gaz. Ce type de décharge produit un plasma chaud, dense et fortement ionisé émettant dans l'EUV. Les échanges thermiques entre le plasma et la paroi peuvent être suffisamment importants pour que la paroi se trouve ablatée. L'utilisation d'un modèle thermique qui détermine l'évolution temporelle de la température de la paroi permet de calculer le seuil d'ablation. Des mesures spectroscopiques du plasma dans plusieurs plages spectrales ont confirmé la présence de ce seuil pour une densité d'énergie injectée de 350 J. Cm-3. Les résultats des mesures spectroscopiques ont été comparés aux résultats issus du modèle.

L’un des défis majeurs pour la conception des capsules de rentrée concerne la modélisation des transferts convectifs et radiatifs à la surface du véhicule. A certains points des trajectoires de rentrée super-orbitale, jusqu’à 40% du flux radiatif total émane du domaine spectral VUV (vacuum ultraviolet), or c’est dans ce domaine que les incertitudes sont les plus fortes. Ce haut niveau d’incertitudes est dû en particulier à un manque de données expérimentales fiables. Le rayonnement VUV est en effet difficile à mesurer en raison de la forte absorption de l’air et des optiques utilisées pour sa mesure. Des difficultés d’analyse supplémentaires sont causées par le fort degré d’auto-absorption et par l’élargissement spectral des raies dans le VUV. L’objectif central de cette étude était d’obtenir des spectres d’émission expérimentaux calibrés dans le VUV afin d’étudier les processus physico-chimiques dans la couche de choc qui contrôlent le flux radiatif. Plus précisément, les objectifs étaient de comparer les spectres observés parallèlement et perpendiculairement à la couche de choc, d’étudier les effets sur l’intensité des raies spectrales émises dans le VUV de l’auto-absorption et de l’élargissement spectral en fonction de la profondeur de champ radiatif (épaisseur optique). Les mesures effectuées perpendiculairement et parallèlement à la surface d’une maquette placée dans l’écoulement représentent un premier jeu de données expérimentales calibrées dans le VUV qui seront utiles pour valider les codes de calcul destinés à prédire le flux radiatif incident. Les mesures obtenues pour différentes profondeurs de champ radiatif représentent quant à elles un ensemble de données expérimentales uniques pour la validation des modèles de transport radiatif et des coefficients d’élargissement des raies. Cette étude s’appuie également sur des simulations numériques afin d’évaluer les prédictions d’un solveur d’écoulement couplé à deux schémas cinétiques à travers la comparaison des spectres mesurés avec les spectres simulés par le code radiatif Specair. Pour atteindre ces objectifs, un banc optique a été conçu et mis en place pour mesurer l’intensité du rayonnement VUV produit autour d’une maquette bidimensionnelle émoussée, avec une résolution spatiale suffisante pour résoudre le profil d’émission dans la couche de choc. La résolution spatiale a été choisie de façon à pouvoir effectuer des mesures du rayonnement dans les zones d’équilibre et hors équilibre de la couche de choc. Un deuxième système a été conçu pour obtenir des mesures du rayonnement VUV incident sur la surface de la maquette. Ce système est constitué d’un hublot placé sur la surface de la maquette et d’un miroir logé à l’intérieur de la maquette pour transmettre le rayonnement vers le système de détection. La profondeur du champ radiatif peut être variée en modifiant la longueur de la maquette, ce qui change l’épaisseur de la couche de choc observée. Le tunnel à détente X2 a été utilisé pour créer les écoulements à haute enthalpie nécessaires pour produire les couches de choc émissives. Deux conditions d’écoulement ont été générées pour cette étude de façon à reproduire des vitesses équivalentes de vol de 10 et 12.2 km/s. Le système spectroscopique utilisé pour ces études comprend un spectromètre McPherson NOVA 225 sous vide couplé à une caméra ICCD Andor iStar de réponse renforcée dans le VUV. Un tube optique scellé par une fenêtre en fluorine a été installé pour prolonger le trajet optique sous vide jusqu’à la maquette de façon à éliminer l’absorption par l’oxygène moléculaire. Le système spectroscopique a été calibré in situ avec une lampe à deutérium placée à l’endroit de la couche de choc rayonnante. L’intensité spectrale incidente sur la surface de la maquette, intégrée entre 115 et 180 nm, est de 0,744 W/cm²sr pour une vitesse d’écoulement de 10 km/s et 12,3 W/cm²sr à 12.2 km/s. [...]
A major design challenge for re-entry capsules lies in the modelling of convective and radiative heat transfer to the surface of the vehicle. At certain points on superorbital re-entry trajectories, up to 40% of the total radiative heat flux is contributed by the vacuum ultra-violet (VUV) spectral range and it is in this spectral range that the largest uncertainties lie. The high level of uncertainty in the VUV is a result of a lack of published experimental data due to difficulties encountered in measuring radiation in the VUV, such as strong absorption by most optical materials and air. Additional complexities of the VUV spectral range include its strongly self-absorbing nature and spectral line broadening. The primary goal of this study was to obtain calibrated spectral measurements in the VUV that enable the investigation of physical processes occurring in the shock layer that influence the incident radiative heat flux. In particular, the issues to be investigated were the variation in spectral radiance observed across a shock layer compared to the spectral radiance measured through the surface, the effects of self-absorption on spectral line intensity and the broadening of spectral lines in the VUV as a function of depth of radiating flow field. The measurements made across and through the surface of a model provide the first set of calibrated experimental results for the validation of computational codes used to predict incident radiative heat flux. Measurements made with a varying depth of radiating flow field provide a unique set of experimental data for the validation of radiation transport models and broadening coefficients. This study also used computational simulations to investigate the accuracy of a flow field solver coupled with two reaction rate schemes and compared the spectra produced using Specair with experimentally measured values. To achieve these goals, an optical system was designed to measure the VUV radiative emission produced around a blunt two-dimensional model in a spatially resolved manner across the shock layer. Spatial resolution allowed for spectral measurements to be made in both the equilibrium and non-equilibrium parts of the shock layer. A second optical system was designed to obtain measurements of VUV radiation incident on the surface of the model. This system incorporated a window in the surface with a mirror housed within the model to deflect the radiation out of the test section and into the detection system. To effectively vary the depth of the radiating flow field, the length of a two-dimensional model was varied, changing the depth of the shock layer being observed. The X2 expansion tube was used to create the high enthalpy flows required to produce radiating shock layers. Two flow conditions were created for this study that represented flight equivalent velocities of 10.0 km/s and 12.2 km/s. The spectroscopy system utilized for this study consisted of an evacuated McPherson NOVA 225 spectrometer coupled to an Andor iStar VUV enhanced intensified charge coupled device. An evacuated light tube sealed with a magnesium fluoride window was required to extend the evacuated light path to the model and avoid any absorption by molecular oxygen. An in-situ calibration of the VUV spectroscopy system was conducted using a deuterium lamp located in the position of the radiating shock layer. The integrated incident spectral radiance measured through the surface of the model between 115 nm and 180 nm was 0.744 W/cm2 sr for the 10.0 km/s condition and 12.3 W/cm2sr for the faster 12.2km/s condition. [...]

A grande maioria das infecções causadas em ambientes médicos-odontológicas é proveniente de contaminações cruzadas, quando se tem contato entre diferentes instrumentos e /ou aparelhos contaminados após procedimentos médicos. Atualmente o padrão aceito e amplamente utilizado para esterilização de instrumental são os equipamentos chamados de autoclaves, em que é reconhecido e aceito pelos órgãos legisladores. Porém alguns tipos de instrumental e material não podem ser esterilizados utilizando este método tendo uma outra vertente que é aplicação de agentes químicos. Esses criam problemas socioambientais relacionados a sua utilização e descarte. Dessa forma, o objetivo deste trabalho foi desenvolver uma autoclave multifuncional com a utilização de gás ozônio, ultravioleta e calor úmido, em que se testou e analisou microbiológica os protocolos de esterilização, obtendo entendimento e otimização do mesmo. Os resultados mostraram-nos que a configuração desenvolvida atingiu aspectos de esterilidade nos protocolos de esterilização avaliados. Entretanto tem a necessidade de aprofundar estudos aplicando o baixo vácuo para o entendimento quanto a utilização quanto os protocolos do funcionamento e uma futura otimização para produção em larga escala.
Most of infection in the medical-dental office is prevenient of cross-contamination, when have the contact with different instrumental and materials without basic control after the process and contact on patient. This point have the standard protocol was accept and described in literature, its utilizing for instrumental sterilizing is the autoclave, it is recognized by organs legislators. However, some instrumental and materials not be accept in this method, on this is necessary one method second in this case is chemical on the instrumentation, but created environmental problem in relation its application. Therefore, this research made the proof of conception in the multifunctional autoclave with the option ozone, ultraviolet and moist heat, what it is analyzing the microbiological protocols of the sterilizing, understanding and optimization the sterilizing process. This results show us which this constructive configuration in this work reached aspects of the sterilizing in the protocols, describe in this text. In the future research in this subject could be study the strongly aspects about the vacuum process before the sterilizing process with ozone gas and development and optimization the prototype for make the scaling up.

A cloração é largamente utilizada para a desinfecção de águas de abastecimento e residuárias, porém o potencial de toxicidade da cloração por seus subprodutos torna o processo menos atrativo. O dióxido de cloro surge como alternativa de desinfecção, porém a sua geração envolve reações bastante dependentes das concentrações de reagentes, das condições físico-químicas, podendo gerar também subprodutos prejudiciais à saúde humana. Outras tecnologias alternativas, como o ozônio e a radiação ultravioleta apareceram como processos tecnicamente viáveis. Neste trabalho buscou-se realizar revisão crítica da literatura existente sobre a desinfecção realizada com radiação ultravioleta e ozônio, bem como investigar e interpretar os aspectos relevantes do desempenho da desinfecção de efluentes de esgoto sanitário com ozônio e com radiação ultravioleta na inativação de coliformes totais e coliformes fecais. Na parte experimental avaliou-se as doses de 80, 95 e 120 mg/L e tempos de contato de 20, 30 e 35 minutos para a desinfecção com ozônio. Na desinfecção com radiação ultravioleta, utilizou-se de tempos de exposição de 10, 30, e 60 segundos, mantendo-se a mesma intensidade média de radiação e variando-se a espessura de lâmina líquida. Nos aspectos observados no decorrer desta pesquisa, verificou-se que para as condições analisadas, a desinfecção com radiação ultravioleta mostrou-se como técnica mais simples e eficaz para a inativação de coliformes fecais e coliformes totais quando comparada à ozonização, apresentando assim vários aspectos favoráveis no que concerne ao modo de operação, a influência da qualidade do efluente bruto, ao controle do processo, entre outros.
The Chlorinate is widely used for the disinfection of waste and drinking water, however the toxicity potential by the by-products of chlorinate renders the process less attractive. The chlorine dioxide comes up as a disinfection alternative, but its production involves highly reagent concentration and physical-chemical condition dependant reactions, also being able to create human health hazardous by-products. Other alternative technologies, like ozone and ultraviolet radiation have risen as technically viable processes. It this work, is has been attempted to review critically the existing literature about the effluent disinfection of sanitary waste, using a comparative approach between the disinfection in which ozone and ultraviolet radiation were used, as well as to investigate and interpret the relevant aspects of sanitary waste effluents disinfection with ozone and ultraviolet radiation on the inactivation of otal and fecal coliforms. In the experimental part doses of 80, 95 and 120 mg/L and contact times of 20, 30 and 35 minutes have been evaluated for the ozone disinfection process. For the ultraviolet method, exposure times of 10, 30 and 60 seconds have been used, keeping the same mean intensity of radiation and varying water layer thickness. With regard to the observed of thios research, is has been verified that, for the analyzed conditions, the ultraviolet disinfection has showed the simplest and most effective method of the inactiviation of fecal andtotal coliforms when compared the ozone method, thus showing several favorable aspects concerning the operation mode, the wal effuent quality influence, the process control, among others.

O presente trabalho desenvolveu um estudo sobre a blenda polimérica Polipropileno/Poli(3-hidroxibutirato) (PP/PHB). Os principais objetivos desta pesquisa foram estudar a compatibilização da blenda PP/PHB, a influência da prévia fotodegradação sobre a biodegradação da blenda e o comportamento individual do PHB frente a fotodegradação. As blendas PP/PHB foram obtidas nas composições 90/10, 80/20, 70/30 e 60/40 (em peso) numa extrusora dupla-rosca. O estudo da compatibilização foi feito para a blenda PP/PHB 80/20 contendo ou não 10% dos seguintes compatibilizantes: polipropileno grafitizado com anidrido maleico (PP-g-MAn), poli(etileno-co-acrilato de metila) (P(E-co-MA)), poli(etileno-co-metacrilato de glicidila) (P(E-co-GMA)) e poli(etileno-co-acrilato de metila-co-metacrilato de glicidila) (P(E-co-MA-co-GMA)). A caracterização dos materiais foi realizada através de análises morfológicas, químicas e ensaios mecânicos (tração e impacto). Os resultados obtidos permitiram classificar a eficácia dos compatibilizantes na seguinte ordem: P(E-co-MA-co-GMA) >> P(E-co-MA) > P(E-co-GMA) PP-g-MAn. A fotodegradação do PHB foi investigada expondo-se este material numa câmara de envelhecimento artificial por 3, 6, 9 e 12 semanas. O efeito da radiação UV no PHB foi monitorado através de mudanças na sua massa molar, estruturas química e cristalina, bem como nas suas propriedades térmicas, morfológicas, óticas, mecânicas e de biodegradação. A radiação UV causou uma série de mudanças em todas as propriedades analisadas. Estes efeitos, entretanto, não se mostraram muito severos e um dos motivos apontados para isso foi a baixa transmitância da radiação UV apresentada pela amostra de PHB estudada, o que gerou um perfil de degradação muito pronunciado neste material. As blendas PP/PHB em todas as suas composições foram submetidas à radiação UV por 2 e 4 semanas e tiveram a sua biodegradabilidade avaliada por ensaios de perda de massa e de respirometria de Bartha (medida da produção de CO2). Os materiais antes e após as diferentes degradações foram caracterizados através de análises químicas, térmicas, morfológicas e de massa molar. Primeiramente, observou-se que, antes de qualquer degradação, a biodegradação da fase PHB foi suprimida dentro das blendas, o que foi atribuído ao PHB constituir a fase dispersa das misturas. A prévia fotodegradação retardou a biodegradação do PHB e acelerou a biodegradação do PP e de todas as blendas PP/PHB. A maior capacidade biodegradativa do PP e das blendas foi relacionada à cisão de cadeia e formação de grupos funcionais oxidados durante a exposição à radiação ultravioleta.
In this work Polypropylene/Poly(3-hydroxybutyrate) (PP/PHB) blend was studied. In particular the compatibilization and the influence of a previous photodegradation on the biodegradation of the blend were investigated. In order to understand the photodegradation of the blends it was also necessary to study the photodegradation of PHB. The compositions of the PP/PHB blends studied ranged from 90/10 to 60/40 (by weight). These blends were obtained using a twin screw extruder. The compatibilization was evaluated using a PP/PHB blend 80/20 containing or not 10% of the following compatibilizers: maleic anhydride grafted polypropylene (PP-g-MAH), poly(ethylene-co-methyl acrylate) (P(E-co-MA)), poly(ethylene-co-glycidyl methacrylate) (P(E-co-GMA)) and poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (P(E-co-MA-co-GMA)). The blends obtained were characterized through their morphological, chemical and mechanical properties (tensile and impact tests). The results obtained enabled the classification of the compatibilizers efficiency in the following order: P(E-co-MA-co-GMA) >> P(E-co-MA) > P(E-co-GMA) PP-g-MAH. PHB photodegradability was investigated through its exposure to artificial UV radiation in a weathering chamber for 3, 6, 9 and 12 weeks. The photodegradation effect was followed by changes of molecular weight, of chemical and crystalline structures, of thermal, morphological, optical and mechanical properties, as well as of biodegradability. UV radiation caused several changes in all the properties evaluated, however, these effects were not very severe. These results could be explained in light of the low UV radiation transmittance of the PHB sample studied, which caused a strong degradation profile for this material. PP/PHB blends in all compositions were exposed to UV radiation for 2 and 4 weeks and had their biodegradability evaluated using the weight loss and the Bartha respirometer tests (CO2 production measurement). The materials before and after the different degradations were characterized by chemical, thermal, morphological and molar mass analysis. First, it was observed that, before any degradation, the biodegradation of the PHB phase was suppressed in the blends, most likely due to the fact that PHB was the dispersed phase within the mixtures studied. Previous photodegradation delayed PHB biodegradation and sped up the biodegradation of PP and all PP/PHB blends. The greater biodegradability of PP and blends was attributed to the chain scission and formation of oxidized functional groups taking place during ultraviolet radiation exposure.

Aquest treball va estudiar la irradiació ultraviolada-visible (UV-Vis) com una alternativa per a la pasteurització de sucs. Els resultats van mostrar que la irradiació ultraviolada no produeix hidroximetilfurfural i es capaç de degradar-lo. Es va proposar un mecanisme de foto-degradació i es van usar diferents models cinètics per descriure la reacció. La foto-degradació de la vitamina C va ser insignificant usant una làmpada d’emissió múltiple. A més, el processament d’UV-Vis va ser efectiu inactivant els enzims polifenoloxidasa i peroxidasa; a major temperatura major inactivació. Mentrestant, la majoria dels paràmetres fisicoquímics van ser pràcticament inalterats i la quantitat inicial de pigments es va reduir. Per tant, el processament d’UV-Vis combinat amb lleu escalfament és una alternativa viable per a la pasteurització de sucs.
Este trabajo estudió la irradiación ultravioleta-visible (UV-Vis) como una alternativa para la pasteurización de zumos. Los resultados demostraron que la irradiación ultravioleta no produce hidroximetilfurfural y es capaz de degradarlo. Se propuso un mecanismo de foto-degradación y se usaron diferentes modelos cinéticos para describir la reacción. Por el contrario, la foto-degradación de la vitamina C fue insignificante usando una lámpara de emisión múltiple. Además, el procesamiento UV-Vis fue efectivo inactivando las enzimas polifenoloxidasa y peroxidasa en zumos; a mayor temperatura, mayor inactivación. Mientras tanto, la mayoría de los parámetros fisicoquímicos fueron prácticamente inalterados y la cantidad inicial de pigmentos fue reducida. Por lo tanto, el procesamiento UV-Vis combinado con un calentamiento suave representa una alternativa viable para la pasteurización de zumos.
This work studied the ultraviolet-visible (UV-Vis) irradiation as an alternative for fruit juice pasteurisation. The results showed that ultraviolet irradiation does not produce hydroxymethylfurfural and is capable of degrade it. A mechanism of photo-degradation was proposed and different kinetic models were used to describe the reaction. On the contrary, the photo-degradation of vitamin C was insignificant using a multi-wavelength emitting lamp. Moreover, the UV-Vis processing was effective inactivating the enzymes polyphenoloxidase and peroxidase in fruit juices. The higher the temperature the higher the inactivation. Meanwhile, most physicochemical parameters were practically unaltered and the initial quantity of pigments was reduced. Therefore, the UV-Vis processing combined with a mild-heating represents a viable alternative for fruit juice pasteurisation.

We demonstrate hyperspectral imaging using two time-delayed, coherent extreme ultraviolet (XUV) sources. The approach combines broadband XUV high-harmonic generation, holographic imaging, and Fourier transform spectroscopy. The two harmonics sources are spatially separated at generation,and overlap in the far field resulting in a double slit diffraction pattern. We record the two-dimensional intensity modulation as a function of relative time delay; the Fourier transform determines the spatially dependent spectrum. To reduce the delay jitter and improve the spectral resolution, we demonstrate a novel experimental setup that records the relative delay of the two pulses through optical interference. Moreover, we have demonstrated that this broadband approach can be extended to Fourier transform holographic imaging, which avoids extensive phase retrieval computations. Applications include imaging of biological materials near the carbon K-edge.

Thesis (Ph. D.)--Indiana University, Dept. of Chemistry, 2007.
Title from dissertation home page (viewed May 29, 2008). Source: Dissertation Abstracts International, Volume: 68-12, Section: B, page: 7987. Adviser: James P. Reilly.

The UK ROSAT Wide Field Camera was used to carry out the first all-sky survey at extreme- ultraviolet wavelengths (EUV). In this thesis, an optimised method for the extraction of survey light curves is developed and applied to an all-sky sample of eighty-one cataclysmic variables. Twenty-two sources were detected with high confidence. The sample of detected systems is dominated by AM Hers, which are found to be exceptionally strong EUV sources. Six of these are new systems, identified through optical follow up of survey sources, and these EUV-selected systems are found to have the most extreme EUV/optical flux ratios. Orbital periods are detected in most AM Hers, and the implications of the new orbital-period distribution of AM Hers are discussed. Phase-folded light curves of a flux limited sample are presented and spectral constraints are applied. Three AM Hers show evidence of spectral modulation with phase. Three intermediate polars are detected, though a distinct EUV emission component is required only in the case of RE 07514+14. Upper limits to other systems show that RE 0751 is unusually bright within the bandpass of the WFC. Limits are placed on temperatures and absorption columns of similar components in other systems, but the WFC does not provide useful limits on the luminosities of such components. The energy balance of intermediate polars remains an open question. Six non-magnetic cataclysmic variables were detected, four of which are dwarf novae caught in their outburst state. These include VW Hyi and SS Cyg, which are discussed in the context of extensive multi-wavelength coverage; incorporating optical, ultraviolet and X-ray observations. SS Cyg was detected as a strong EUV source during decline, which was found to be faster than the optical decline. VW Hyi was observed throughout an optical outburst, with but no enhancement of EUV flux. This suggests the EUV flux detected by EXOSAT must lie softwards of ~ 70 eV. WFC limits show that the boundary layer of VW Hyi during outburst must be less luminous than the disk. In VW Hyi and SS Cyg the hard X-ray flux is suppressed during outburst, and remains low until the very end of optical decline. This is taken as evidence that the hard X-ray flux is regulated by the boundary layer.

Aerosol particulate matter adversely affects the climate, environment and human health. Mechanistic studies have indicated that ultrafine aerosol nanoparticles, those under 100 nm in diameter, may have significant health impacts due to their relatively high number concentration, surface area and potential for deep penetration into the human lung. However, epidemiological evidence remains limited due to the lack of measurement networks that monitor local concentrations of ultrafine particles. Direct ultraviolet (UV) photoionisation electrically charges aerosol nanoparticles for subsequent detection by a mechanism distinct from the ion-particle collisions of conventional methods. The aim of this work is to evaluate photoionisation theory in order to understand and interpret measurements from a low-cost aerosol particle sensor. To accomplish this, theoretical equations are analysed, modelled and compared with experimental results for validation. The photoelectric yield of aerosol particles is explored in terms of particle size, concentration, material, and morphology giving insight into the interaction of light and particles. This thesis introduces the first analysis of photoionisation, recombination, convection/diffusion and transport of particles in an electric field using analytical, numerical, and computational fluid dynamics (CFD) techniques. Characteristic times and dimensionless parameters are defined to determine regimes under which the measurement system is dominated by each of the charging or transport mechanisms. The level of modelling detail required for accurate prediction of aerosol charging and capture methods is demonstrated over a range of conditions. In a continuous flow of aerosol particles, an electric field is applied to capture charge as it is photoemitted from particles and before the emitted charge and particles can recombine. This method yields a novel current measurement directly representative of photoemission. The CFD model agrees well with electrical current measurements demonstrating that the physics of the problem is suitably represented. It is demonstrated that photoemission is linearly proportional to total (mobility) surface area for a large range of sizes and concentrations of particles of self-similar material and morphology, with agglomerated silver particles having 5$\times$ yield of agglomerated carbon from a propane flame. It is shown for the first time that agglomerated particles have a significantly higher photoelectric yield (2.6$\times$) than sintered, close-packed spheres of the same mobility diameter and material, directly contradicting two of the three previous relevant studies. Close-packed spheres have less material exposed to both the photon flux and the particle's surroundings than an agglomerate of the same particle mobility diameter, thereby reducing photoelectric activity. The photoelectrically active area is defined explicitly in this work to reflect the effect of a particle's morphology; the revised definition produces good agreement with experimental results.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.
Includes bibliographical references (p. 55-56).
We demonstrate the use of a focused ultraviolet laser as a track calibration source in drift chambers, and specifically in a small time projection chamber (TPC). Drift chambers such as TPCs reconstruct the trajectories of charged particles by amplifying and collecting electrons produced by ionization of gas atoms with which the target particle collides. The ultraviolet laser induces a two-photon ionization of gaseous organic compounds along the beam, providing an artificially produced track which may then be used as a calibration source, particularly because it behaves as a particle of infinite momentum whose trajectory is straight in a magnetic field. To this end, we present measurements of the ionization profile of the laser for various gasses and model this ionization in terms of photon flux.
by Grant Elliott.
S.B.

In photolithography, increasing pattern density is a key issue for development of semiconductor devices. Extreme ultraviolet (EUV) radiation is the next generation light source for overcoming the resolution limit of conventional photolithography in order to obtain nanostructures of higher density. In this thesis, we focus on investigating resolution limits of interference patterns produced by EUV radiation. Optical properties of interference fringes obtained using different types of compact EUV sources are studied with regard to increasing pattern density. Rigorous simulations of optical wave propagation of EUV radiation are performed to investigate the resolution limits of interference fringes for the fractional Talbot effect, the achromatic Talbot effect, and an image of Talbot carpet that has an optical property of ever-decreasing size of interference fringes. In experiments, interference lithography has been performed with three different types of compact EUV sources including a gas discharge produced plasma, a plasma based EUV laser, and a high-harmonic generation source. We analyze optical characteristics of particular EUV sources resulting in different capabilities of patterning. Also different optical system designs capable of overcoming the limitations of optical properties of EUV radiation are investigated. We expect that the study of EUV interference lithography can be helpful for understanding the upcoming photolithography resolution and also can be useful as a technology for fabricating very fine structures.

L'observation des quasars dans l'ultraviolet donne acces a la distribution spectrale d'energie dans l'ultraviolet (uv) lointain et extreme ainsi qu'a l'opacite du milieu intergalactique. Nous avons developpe un modele d'opacite du milieu intergalactique en utilisant les donnees les plus recentes sur les differents types d'absorbants obtenues avec le telescope spatial hubble. A partir des resultats de l'experience ballon d'imagerie foca, nous avons constitue deux echantillons de quasars selectionnes par leur emission uv a = 2000 a (m#2#0#0#0 < 19). L'analyse de ces echantillons a ete realisee a partir de methodes statistiques de survival analysis et d'un modele d'accumulation des quasars dans l'espace prenant en compte notre modele d'opacite. L'etude de la distribution des couleurs uv-b des quasars a permis de montrer que la valeur moyenne de l'indice spectral est de l'ordre de 1 (avec un flux de la forme f# #-#) dans le domaine 800 3600 a dans le referentiel du quasar, mais presente une forte dispersion. Une etude comparative realisee en regroupant toutes les informations connues a ce jour sur l'indice spectral optique et ultraviolet montre que l'indice spectral est relie a la longueur d'onde par une loi de puissance d'exposant proche de 1,5 pour z < 1,5. Une evolution moderee avec z est possible. La densite surfacique observee des quasars a la magnitude uv de 19 est de 19 par degre carre, en bon accord avec les predictions du modele d'accumulation. Conforte par cet etalonnage, ce modele a ete utilise pour preparer galex, un sondage complet du ciel en uv recemment selectionne par la nasa, en termes de distribution de couleurs, comptages en magnitude et decalage spectral. On attend avec galex l'observation de plus de 700 000 quasars a la magnitude uv = 19,5 ce qui promet d'importants progres dans la connaissance des quasars dans l'uv lointain et extreme

This thesis details the use of extreme ultraviolet (EUV) sources in probing laser ablation and material opacity. The radiation hydrodynamic codes POLLUX and h2d are used to study the Rayleigh-Taylor instability in a regime relevant to inertial fusion energy and, in support of experimental effort, to test the feasibility of methods for measurement of iron opacity. Simulations of EUV radiography using the POLLUX code show how the presence of warm, dense material leads to strong absorption of the probe beam. Methods using both broad and narrowband EUV wavelength probes for benchmarking theoretical models of opacity are presented. An iron opacity experiment conducted at the Bhabha Atomic Research Centre is modelled, where K_alpha emission from an aluminium layer is used to probe an iron layer beneath. H2d simulations of laser heated iron, conducted to determine the suitability of experimental results obtained at the Rutherford Appleton Laboratory for iron opacity, show the difficulty in preventing large temperature and density gradients from forming. Interferometry has been used to measure both transmission and phase information for a 21.2 nm zinc EUV laser beam probing longitudinally through laser ablated CH plastic at the Prague Asterix Laser System. By conducting interferometric probing with EUV laser light, the region of warm dense matter between the critical surface and ablation surface in a laser ablated plasma is diagnosed. Analysis of phase shifts reveals refractive indices below solid and plasma values arising in CH plastic, due to bound-free absorption in C+, a model for which is presented. The transmission of the EUV probe beam provides a measure of the rate of ablation, matching previous experimental scaling laws.

L’irradiance spectrale solaire (SSI) dans la bande ultraviolette est un paramètre-clé pour la spécification de la moyenne et la haute atmosphère terrestre. Elle est requise dans de nombreuses applications en météorologie de l’espace, et aussi pour l’étude du climat. Or les observations souffrent de plusieurs défauts : manque de couverture spectrale et temporelle permanente, dégradation des capteurs, désaccords entre les instruments, etc. Plusieurs modèles de reconstruction de la SSI ont été développés pour pallier à ces difficultés. Chacun souffre de défauts, et la reconstruction du spectre en-dessous de 120nm est un réel défi. C’est dans ce contexte que nous avons développé un modèle empirique, qui recourt au champ magnétique photosphérique pour reconstruire les variations du spectre solaire. Ce modèle décompose les magnétogrammes solaires en différentes structures qui sont classées à partir de leur aire (et non sur la base de leur intensité, comme dans la plupart des autres modèles). La signature spectrale de ces structures est déduite des observations, et non pas imposée par des modèles de l’atmosphère solaire. La qualité de la reconstruction s’avère être comparable à celle d’autres modèles. Parmi les principaux résultats, relevons que deux classes seulement de structures solaires suffisent à reproduire correctement la variabilité spectrale solaire. En outre, seule une faible résolution radiale suffit pour reproduire les variations de centre-bord. Enfin, nous montrons que l’amélioration apportée par la décomposition du modèle en deux constantes de temps peut être attribuée à l’effet des raies optiquement minces
The spectrally-resolved radiative output of the Sun (SSI) in the UV band, i.e. at wavelengths below 300 nm, is a key quantity for specifying the state of the middle and upper terrestrial atmosphere. This quantity is required in numerous space weather applications, and also for climate studies. Unfortunately, SSI observations suffer from several problems : they have numerous spectral and temporal gaps, instruments are prone to degradation and often disagree, etc. This has stimulated the development of various types of SSI models. Proxy-based models suffer from lack of the physical interpretation and are as good as the proxies are. Semi-empirical models do not perform well below 300 nm, where the local thermodynamic equilibrium approximation does not hold anymore. We have developed an empirical model, which assumes that variations in the SSI are driven by solar surface magnetic flux. This model proceeds by segmenting solar magnetograms into different structures. In contrast to existing models, these features are classified by their area (and not their intensity), and their spectral signatures are derived from the observations (and not from models). The quality of the reconstruction is comparable to that of other models. More importantly, we find that two classes only of solar features are required to properly reproduce the spectral variability. Furthermore, we find that a coarse radial resolution suffices to account for geometrical line-of-sight effects. Finally, we show how the performance of the model on different time-scales is related to the optical thickness of the emission lines

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A radiação ultravioleta (RUV) é considerada o principal agente etiológico no desenvolvimento do câncer de pele. Estudos epidemiológicos apontam para um crescimento mundial de casos novos de câncer cutâneo, superando até mesmo o câncer de pulmão, próstata e mama. Atribui-se esse aumento à degradação do Ozônio estratosférico (O3) e a intensidade da RUV que atinge a superfície terrestre. Diante do exposto, este trabalho pautou-se no estudo da variabilidade temporal do O3, coletado através do sensor TOMS (Total Ozone Mapping Spectrometer) da NASA, para se determinar o grau de influência na intensidade da RUV na região Oeste do Estado de São Paulo. Para análise da variabilidade da RUV, utilizou-se o Índice UV (IUV), que determina a intensidade da RUV na superfície terrestre. Também foi elaborado um Banco de Dados de câncer de pele diagnosticados dentro da área de estudo, para se determinar o perfil epidemiológico dessa enfermidade. Os dados de câncer de pele foram obtidos em três laboratórios que realizam exames anatomopatológicos. Através do método investigativo, por meio de aplicação de questionários, procurou-se também, identificar o comportamento da população em relação aos hábitos de exposição ao sol para se determinar possíveis grupos de risco. Os resultados obtidos mostraram que o O3 apresentou comportamento cíclico em decorrência das estações do ano, com maiores valores na primavera e menores no outono, com média anual em torno de 264 UD.
The longstanding and frequent exposures to the ultraviolet radiation (UVR) are considered the main etiological agent in developing skin cancer. Epidemiological studies point at a global growing in the numbers of new skin cancer cases, even surpassing lung, breast and prostate cancers. It is supposed that the increase in the flux of the photobiologically active radiation is due to the stratospheric ozone (O3) depletion. This work was based upon studying time-spatial variation of the stratospheric O3, using data from TOMS (Total Ozone Mapping Spectrometer) sensor from NASA, in order to determinate the degree of influence of UVR over the western region of São Paulo State, Brazil. To perform an analysis of the UVR variability it was used the UV Index (UVI), a dimensionless parameter, which define the UVR intensity over de earth surface. As contribution to the public polices programs for health, looking for skin cancer prevention, a data bank of new cases of skin cancer was created, with the cases registered in the study area, in order to define the epidemiological profile of this disease. Skin cancer data were extracted from anatomy-pathological biopsies reports collected in three laboratories in Presidente Prudente, SP, Brazil. By means of the investigative method applying questionnaires, it looked for identify the population behavior related to the sun exposure habits in order to determine potential risks groups. Results had shown that stratospheric ozone over the study area presents a cyclic behavior because of the seasons of the year, with higher values in Spring and lower in Fall, with annual average about 264 UD.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A borreliose aviária é uma doença septicêmica aguda, causada pela espiroqueta Borrelia anserina, atualmente apresenta baixa incidência, porém devido ao crescimento das criações orgânicas e rústicas, maior preocupação com o bem estar animal e a diminuição do uso de antibióticos em rações, existe a preocupação com o surgimento de surtos da doença, que poderão causar prejuízos econômicos. Desta maneira, torna-se de fundamental importância a busca por terapias alternativas, entre elas, a terapia fotodinâmica, como a associação da luz ultravioleta (UV) e riboflavina, com o objetivo de controlar a enfermidade. Este estudo objetivou verificar a eficácia do tratamento com luz UV e riboflavina para inativar ou eliminar a B. anserina no soro de galinhas poedeiras, por meio de exames diagnósticos e laboratoriais, e verificar a resposta imunológica do hospedeiro. O experimento foi conduzido em duas etapas, a etapa in vivo foi formada por 42 galinhas, divididas em sete grupos, composto por seis aves: Grupo 1 (saúde); Grupo 2 (doença) inoculadas com soro parasitado por B. anserina; Grupo 3 (imunossupressor) que receberam metilprednisolona; Grupo 4 ( luz UV) que receberam soro parasitado tratado com luz UV; Grupo 5 (riboflavina) que receberam soro parasitado tratado com riboflavina; Grupo 6 (grupo veículo) que receberam soro parasitado tratado com cloreto de sódio 0,9%; Grupo 7 (tratado) que receberam soro positivo para B. anserina tratado com luz ultravioleta associada à riboflavina. A etapa in vitro, foi realizada com placas de cultivo celular, divididas igualmente à etapa in vivo. Foi possível observar que o tratamento não apresentou resultado esperado na inativação ou completa eliminação do agente. No entanto, uma ave do grupo tratado sobreviveu e apresentou recuperação clínica e laboratorial, apresentando espiroquetemia no Momento 11 e qPCR positivo no momento...
Avian borreliosis is an acute septicemic disease caused by the spirochete Borrelia anserina, has a low incidence, however due to the growth of organic and rustic creations, greater concern for animal welfare and reducing the use of antibiotics in feed, there is concern about the emergence of disease outbreaks, which may cause economic losses. Thus, it becomes fundamental to search for alternative therapies, including, photodynamic therapy, such as the combination of ultraviolet (UV) light and riboflavin with the aim of controlling the disease. This study aimed to investigate the efficacy of treatment with riboflavin and UV light to inactivate or eliminate B. anserina from serum laying hens by diagnostic and laboratory tests and to check to the host immune response. The experiment was conducted in two stages. The first one was the in vivo step composed of 42 chickens, divided into seven groups of six birds: Group 1 (health); Group 2 (disease) inoculated with the serum parasitized by Borrelia anserina; Group 3 (immunosuppressant) receiving methylprednisolone; Group 4 (UV light) which received parasitized saline treated with UV light; Group 5 (riboflavin) which received parasitized serum treated with riboflavin; Group 6 (solvent group) parasitized receiving saline treated with 0.9% sodium chloride; Group 7 (treated) which received positive serum for B. anserina treated with ultraviolet light associated with riboflavin. The secund one was the in vitro stage performed with cell culture plates, equally divided in vivo step. It was observed that the treatment did not show expected results in the inactivation or complete elimination of the agent. However, one bird from the treated group survived and showed clinical and laboratory recovery, presenting spirochetemia at the time 11 and qPCR positive at the time...
FAPESP: 2014/03353-4

Orientador: Carlos Kenichi Suzuki
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: O tratamento por plasma térmico de resíduos hospitalares gera como subproduto um material vitrocerâmico com alto poder de bloquear radiação ultravioleta e infravermelho próximo. A composição deste material apresenta como elementos majoritários cálcio, silício, ferro, alumínio e oxigênio. O objetivo deste trabalho é compreender a cinética de devitrificação das múltiplas fases do vitrocerâmico pelo controle do tratamento térmico e o seu efeito na absorção de radiação ultravioleta. Determinou-se por análise térmica diferencial as temperaturas de fusão e recristalização. Amostras vítreas obtidas por fusão a 1300 °C seguido por resfriamento rápido foram tratadas termicamente para induzir a devitrificação. Através da técnica de difração de raios-X identificou-se três estruturas cristalinas, Mg(Al,Fe)2O4, Ca(Ti,Mg,Al)(Si,Al)2O6 e NaAlSiO4, e determinou-se o tamanho médio e quantidade dos cristalitos presentes nessas fases com as diferentes temperaturas de tratamento térmico. As fases cristalinas formadas exercem influência na absorção óptica na faixa de ultravioleta, possibilitando a aplicação deste vitrocerâmico como agente ativo em bloqueadores ultravioleta comerciais. Medidas de transmitância óptica mostraram que o crescimento das fases Ca(Ti,Mg,Al)(Si,Al)2O6 e NaAlSiO4 induziram um fator de redução de 55% para 6% nos valores de transmitâncias ópticas no espectro ultravioleta (290 a 400 nm). A relevância deste trabalho revela-se no controle da formação das fases cristalinas do material que contribuem efetivamente na absorção da radiação ultravioleta
Abstract: A glass-ceramic material generated by plasma treatment of hospital waste has a remarkable property to block ultraviolet and near infrared radiation. The main composition elements of such a glass-ceramic are: calcium, silicon, iron, aluminum and oxygen. The objective of the present research is to understand the kinetics of devitrification of multiple phases by the control of thermal treatment conditions, and their effect on the ultraviolet absorption. The melting and crystallization temperatures of the glass-ceramic material were determined by differential thermal analysis. Vitreous samples were obtained by melting the as-received material at 1300 °C, followed by quenching. Afterwards, samples were thermally treated, inducing controlled crystallization. By X-ray diffraction technique, three crystalline phases were identified: Mg(Al,Fe)2O4, Ca(Ti,Mg,Al)(Si,Al)2O6 and NaAlSiO4. Average size and concentration of the crystallites were also determined. The formed crystalline phases have strong influence in the optical absorbance at ultraviolet band, which allows this glass-ceramic to be used as an active agent in commercial ultraviolet blockers. Optical transmittance measurements showed that the growth of nano-order crystalline phases Ca(Ti,Mg,Al)(Si,Al)2O6, and NaAlSiO4 reduced the optical transmittance from a factor of 55% to 6% at the ultraviolet band (290 to 400 nm). The relevance of this work is shown on the effect of size and concentration of crystalline phases, that contributes to the optical absorption of ultraviolet radiation
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica

Thesis (M.S. in Systems Engineering (Electronic Warfare)) Naval Postgraduate School, September 1993.
Thesis advisor(s): David D. Cleary. "September 1993." Bibliography: p. 58. Also available online.

This thesis describes the development and characterizationof a liquidxenon- jet laser-plasma source forextreme-ultraviolet (EUV) radiation. It is shown how thissource may be suitable for production-scale EUV lithography(EUVL).

EUVL is one of the main candidates to succeeddeep-ultraviolet (DUV) lithography for large-scalemanufacturing of integrated circuits (IC). However, a majorobstacle towards the realization of EUVL is the currentunavailability of a source meeting the tough requirements onespecially power and cleanliness for operation in an EUVLstepper. The liquid-xenon-jet laser-plasma concept has keyadvantages that may make it suitable for EUVL since, e.g., itsplasma consists only of the inert noble gas xenon and since theliquidjet target technology enables plasma operation at largedistances from the source-hardware thereby reducing sputteringand to allowing for high-power operation.

At the beginning of the work described in this thesis, aspatial instability of the liquid-xenon-jet made stableoperation of a plasma at practical distances from the nozzleorifice dicult. However, an invention of a stabilization methodbased on applying localized heating to the tip of thejet-forming nozzle, resulted in stable jet operation. Thelongitudinal droplet stability of a liquid-droplet laser-plasmasource has also been investigated and improved.

Continuous improvements of especially the laser-power toEUV-radiation conversion eciency (CE) and the stability oflaser-plasma operation at large distances (several centimeter)from the nozzle are reported for the liquidxenon- jet laserplasma source. Furthermore, this source is characterizedregarding many parameters relevant for EUVL operationincluding, ion emission from the plasma and related sputteringof nearby components, source size and shape, therepetition-rate limit of the source and non-EUV emission fromthe plasma.

Although the main focus of the thesis has been thedevelopment and characterization of a liquid-xenon-jetlaser-plasma source for production-scale EUVL, the source mayalso be suitable for small field applications that benefit fromthe high potential brightness of the source. A method to scanthe plasma and thus minimize the photon losses whilemaintaining the object plane uniformity was developed.Furthermore, the first operation of a liquidtin- jet laserplasma is reported. Quantitative EUV flux measurements yieldrecord CE, but quantitative contamination measurements alsoindicate that a liquid-tin-jet laser plasma is not likely to beapplicable as a source for EUVL.

Aluminum Gallium Nitride (AlGaN) / Gallium Nitride (GaN) based deep ultraviolet (DUV) light emitting didoes (LEDs) with emission wavelengths between 200-280 nm enable key emerging technologies such as water/air purification and sterilization, covert communications and portable bio-agent detection/identification systems for homeland security, and surface and medical device sterilization. These devices produce a large amount of undesired heat due to low quantum efficiencies in converting electrical input to optical output. These low efficiencies are attributed to difficulties in the growth&doping of AlₓGa₁₋ₓN materials and UV absorbing substrates leading to excessive joule heating, which leads to device degradation and a spectral shift in the emission wavelength. With this regard, effective thermal management in these devices depends on the removal of this heat and reduction of the junction temperature. This is achieved by decreasing the package thermal resistance from junction-to-air with cost-effective solutions. The use of heat sinks, thermal interface materials, and high conductivity heat spreaders is instrumental in the reduction of the overall junction-to-air thermal resistance. This thesis work focuses on thermal modeling of flip-chip packaged deep UV LEDs to gain a better understanding of the heat propagation through these devices as well as the package parameters that have the biggest contributions to reducing the overall thermal resistance. A parametric study focusing on components of a lead frame package is presented to ascertain the thermal impacts of various package layers including contact metallizations, thermal spreading sub-mounts, and thermal interface materials. In addition the use of alternative thermal interface materials such as phase change materials and liquid metals is investigated experimentally.