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1
Roig, Benoît. "Couplage UV/UV : applications analytiques environnementales". Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11052.
Testo completoAbstract (sommario):
L'objectif de cette etude est de proposer des methodes de mesure simples et rapides de la qualite des eaux, pouvant se substituer aux methodes de reference. Pour cela, des techniques basees sur l'utilisation de rayonnement ultraviolet (reactions photochimiques et spectrophotometrie) ont ete utilisees au sein d'un nouveau concept appele couplage uv/uv. L'interet et l'efficacite de ce couplage ont ete prouves au travers de differentes applications environnementales comme la determination de parametres de pollution des eaux que sont les formes azotees et phosphorees. Les procedures developpees sont plus rapides, moins contraignantes et tout aussi performantes que certaines methodes de reference. L'application du couplage uv/uv a permis egalement de developper des procedures de mesure de composes non absorbants dans le domaine ultraviolet (sucres et poly-alcools), et dont la determination par les methodes classiques est difficile. Enfin, l'etude a partir de molecules aromatiques modeles fait apparaitre le couplage uv/uv comme prometteur pour le suivi de procedes d'epuration d'effluents industriels refractaires aux traitements classiques. Le couplage uv/uv apparait donc comme une technique tres interessante, pour la mesure de parametres specifiques et le controle de procedes de degradation et novatrice par son approche integree.
2
McGonigle, A. J. S. "Tunable UV lasers". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343230.
Testo completo
3
Rizzini, Luca [Verfasser], e Roman [Akademischer Betreuer] Ulm. "UVR8: a plant UV-B photoreceptor = UVR8: ein pflanzlicher UV-B Photorezeptor". Freiburg : Universität, 2011. http://d-nb.info/1123457891/34.
Testo completo
4
Headland, Lauren R. "UV-resistance locus 8 and UV-B specific signaling in Arabidopsis thaliana". Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/1757/.
Testo completoAbstract (sommario):
UV-B is a natural component of the sunlight spectrum. As a result of the potentially harmful effects of this radiation, plants have evolved a highly effective suit of protective and repair mechanisms. However, the signalling pathways that control such responses are not yet well known. For example while the photoreceptors responsible for red and blue light responses are well characterised, no such UV-B photoreceptor has yet been identified. Despite this particularly large gap in our knowledge, previous work identified the first UV- B specific signalling component which, unlike the more general stress-associated pathways often seen at high doses, specifically regulates expression of genes in response to even very low fluence rates of UV-B. This protein, UV-RESISTANCE LOCUS 8 (UVR8) regulates the induction of a number of photoprotective genes mostly via the transcription factors ELONGATED HYPOCOTYL 5 (HY5) and HY5 HOMOLOGUE (HYH). The end result of this pathway is the production of photoprotective compounds such as the flavonoids which enhance a plants ability to withstand UV-B stress. Thus UVR8 promotes plant fitness under these conditions. While we know that UVR8 binds to chromatin in the promoter region of HY5 and that it accumulates in the nucleus under UV-B, many other questions about this particular protein remain unanswered. For example, we do not yet know if UVR8-mediated UV-B signalling involves other factors which interact with UVR8 nor do we understand the mechanism by which UVR8 localisation is mediated. In addition, although we are aware of the importance of UVR8 in UV-B acclimation, it is unclear what roles might be played by other genes and proteins acting independently of this pathway. Therefore, the aims of this study were to investigate low fluence UV-B pathways that may act independently of UVR8 and to further examine the UVR8 protein itself both in terms of its interactions with other proteins and also in the role of the N-terminal region in regulation of its localisation. To achieve the first of these aims, RNA samples derived from plants treated with low fluence UV-B were submitted for microarray analysis. It was initially determined that the total number of genes induced was roughly equal in both low fluence treated samples and also to that found in the previous microarray performed by Brown et al. (2005) at a comparatively higher fluence. Thus, as only 72 genes have currently been linked to UVR8, there do appear to be many low-fluence UV-B induced pathways besides that regulated by UVR8. Several genes were analysed further using RT-PCR and qPCR methods in order to confirm their independence from the UVR8 signalling pathway components as well as assess their dependence on other hypothesised UV-B sensory mechanisms. It was found that while some genes did seem to be expressed independently of known photoreceptors, DNA damage signals as well as UVR8, HY5, HYH and COP1; one gene was expressed in a COP1-dependent but UVR8 independent manner. It therefore appears that at least four classes of genes are induced by UV-B; low fluence UVR8/HY5/HYH independent COP1 dependent, low fluence UVR8/HY5/HYH/COP1 dependent, low fluence UVR8/HY5/HYH/COP1 independent and finally high fluence non- specific signalling. The second portion of this thesis examined the structure and function of UVR8 in greater detail. To assist in this analysis, the BLAST sequence homology tool was used to probe both the Arabidopsis genome and available green plant sequences. It was found that 23 UVR8-like sequences exist in Arabidopsis but none of these appear to have similar N or C-terminal sequences to UVR8. As these two regions have previously been shown to be of vital importance in UVR8 function (Kaiserli and Jenkins, 2008; Kaiserli unpublished data) it is unlikely that any are acting in a redundant fashion to UVR8. A number of similar proteins to UVR8 can be found in other plant species. These potential homologues however fall into two categories based on their closer similarity with either UVR8 or its close homologue in humans REGULATOR OF CHROMATIN CONDENSATION 1 (RCC1). The wide variety of plant species that did show UVR8-like proteins suggests that this particular means of UV-B acclimation may have arisen relatively early with the colonisation of land plants. Interestingly, many of these likely homologues had a conserved N terminal. The N-terminal of UVR8 has previously been show to have a role in UV-B dependent nuclear accumulation (Kaiserli and Jenkins, 2008). This was examined further in Chapter 4 through the generation of a number of deletion and addition constructs in both a stable Arabidopsis uvr8-1 background as well as transiently in tobacco. From analysis of localisation of these constructs via confocal microscopy it was determined that the first 12 amino acids are sufficient but not necessary for nuclear accumulation, while the first 20 appear to be both necessary and sufficient. Indeed, it was shown that the initial 32 amino acids also confer constitutive localisation of a GFP tag in the nucleus regardless of light condition and despite the presence of a nuclear exclusion signal (NES). It therefore appears that this region, which shows strong conservation with UVR8-like proteins in other plant species, is of vital importance to the nuclear accumulation seen under UV-B. Finally, in Chapter 5, the possibility that UVR8 may be acting as part of a complex was explored. This involved use of size exclusion chromatography to provide approximate sizes of the UVR8 protein complex. It was found that native UVR8 appears to exist in a complex of about 70-90 kDa in size. This suggests that at least one other protein interacts stably with UVR8. Other fusion constructs were also analysed in this way, however the results were more difficult to interpret due the apparent artificial dimerisation of the GFP tag. In summary, the work presented here has shown that although UVR8 dependent pathways are predominant, a variety of low fluence UV-B induced genes and pathways may exist. Homology searches and mutational analyses suggest that the N-terminal region of UVR8 plays a critical role in its function and localisation. Finally, size exclusion chromatography suggests that UVR8 forms a complex in vivo with as yet uncharacterised partner proteins. In total these results provide further insight into the mechanisms UVR8 action and highlight new avenues for both UVR8 dependent and independent UV-B signalling.
5
Peng, Sheng. "Ultraviolet sources for advanced applications in the vacuum UV and near UV". W&M ScholarWorks, 2004. https://scholarworks.wm.edu/etd/1539623467.
Testo completoAbstract (sommario):
This dissertation documents a systematic study consisting of experimental investigations and theoretical analyses of intense ultraviolet sources in VUV and near-UV. Some engineering issues regarding two prototypes of electrodeless lamps using rf and microwave are discussed.;Various excimers that produce intense UV light are investigated, including: (1) A benchmark Xe2 excimer which has been proven to be very efficient in our novel rf capacitively coupled discharge lamp; (2) A rarely studied excimer, KrI, which suffers from predissociation and was reported to be very weak or invisible by most of other studies; (3) XeI excimer whose emission dominates around 253 nm and is promising as a mercury-free lamp for antibacterial applications. In the above studies, discharge temperatures are estimated from the emission band width. An elaborate kinetic model is developed for KrI to account for the KrI* and I2* intensities as a function of pressure. It was found that Kr2* plays the rule for energy transfer instead of Kr* in the pressure of interest. The electromagnetic wave interaction with charge particles is studied in our 2D and 3D EM-PIC simulations for both the rf and microwave lamps. Important plasma parameters, such as the electron density and temperature are obtained for various pressures. The electron energy distribution function that is important to account for excimer excitation is obtained.;We also performed a high-level ab initio calculation in Gaussian to produce the ground state potential curve for KrI, which agrees with previous scattering experiments and is necessary for predicting spectral emissions. as a systematic study to account for the KrI emission spectra at high pressure, we use a semiclassical model to account for emissions between a bound excited state and an unbound ground state. An explicit expression is obtained to represent the observed spectral intensity. Important molecular constants are obtained for KrI and compared with previous results.
6
Mead, C. J. "Some UV curable systems". Thesis, University of Kent, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252581.
Testo completo
7
Patil, Raj. "Deep UV Raman Spectroscopy". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613378.
Testo completoAbstract (sommario):
This thesis examines the performance of a custom built deep UV laser (257.5nm) for Raman spectroscopy and the advantages of Raman spectroscopy with a laser in the deep UV over a laser in the visible range (532 nm). It describes the theory of resonance Raman scattering, the experimental setup for Raman spectroscopy and a few Raman spectroscopy measurements. The measurements were performed on biological samples oak tree leaf and lactobacillus acidophilus and bifidobacteria from probotioc medicinal capsules. Fluorescence free Raman spectra were acquired for the two samples with 257.5 nm laser. The Raman spectra for the two samples with a 532nm laser was masked with fluorescence. Raman measurements for an inorganic salt sodium nitrate showed a resonance Raman effect with 257.5 nm laser which led to enhancement in the Raman intensity as compared to that with 532 nm laser. Therefore we were able to demonstrate two advantages of deep UV Raman spectroscopy. First one is the possibility of acquiring fluorescence free spectra for biological samples. Second is the possibility of gaining enhancement in Raman intensity due to resonance Raman effect. It was observed that 257.5 nm laser requires optimization to reduce the bandwidth of the laser to get better resolution. The 257.5 nm laser also needs to be optimized to obtain higher power to get better signal to noise ratio. The experimental setup can also be further improved to obtain better resolution. If the improvements required in the setup are implemented, the deep UV Raman setup will become an important tool for spectroscopy.
8
Chittavanich, Pongsith P. "Pigmented UV-Curable Alkyd". University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1259614294.
Testo completo
9
Xu, Tong. "UV-Curable Hybrid Polyurethanes". University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1406471515.
Testo completo
10
Keltner, Lucas A. "UV Properties of Galileons". Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1436970587.
Testo completo
11
Xu, Rongcheng Xu. "Anticorrosion UV Curable Alkyds". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1510747493751126.
Testo completo
12
Pavelka, Radek. "Detekce nánosu UV lepidla". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377342.
Testo completoAbstract (sommario):
This diploma thesis focuses on a design of camera control system used for detecting defects, appearing during a UV luminescent glue application on the bottom of a paper bag. As a part of this thesis, an application was developed, using Baumer VCXG-53C industrial camera, implementing two dierent control methods - 2D cross correlation image pattern matching based on previously user defined pattern and glue area size measuring based on binary segmented image. The result of this work is a fully developed control system, prepared to be put into operation at the customer’s production line.
13
Třešňáková, Andrea. "Materiálový tisk UV dozimetrů". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-316153.
Testo completoAbstract (sommario):
The subject of this theses is a preparation of chemical UV dosimeters working on diverse principles and their printing. Three UV dosimeters were prepared. The first one is based on a photocalalytic reaction of titanium dioxide with redox dyes. Two other dosimeters are based on a reaction of a photolabile substance able to produce an intermediate reacting with a dye. Prepared dosimeter compositions were coated using a material roll-to-roll printing machine on a corona-treated PET foil. Prepared dosimeter compositions were calibrated for desired exposition to UV radiation doses. Validity of a reciprocity law was verified.
14
Huang, Ying. "Applications of UV/H2O2, UV/NO3–, and UV-vis/ferrite/sulfite Advanced Oxidation Processes to Remove Contaminants of Emerging Concern for Wastewater Treatment". University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535703890003601.
Testo completo
15
Ye, Zhengcai. "UV Disinfection between Concentric Cylinders". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14641.
Testo completoAbstract (sommario):
Outbreaks of food-born illness associated with the consumption of unpasteurized juice and apple cider have resulted in a rule published by the U.S. Food and Drug Administration (FDA) in order to improve the safety of juice products. The rule (21 CFR120) requires manufacturers of juice products to develop a Hazard Analysis and Critical Control Point (HACCP) plan and to achieve a 5-log reduction in the number of the most resistant pathogens. Ultraviolet (UV) disinfection is one of the promising methods to reach this 5-log reduction of pathogens. The absorption coefficients of juices typically vary from 10 to 40 1/cm and can be even higher depending on brand and processing conditions. Thin film reactors consisting of two concentric cylinders are suitable for inactivating pathogens in juices. When the two concentric cylinders are fixed, the flow pattern in the gap can be laminar Poiseuille flow or turbulent flow depending on flow rates. If the inner cylinder is rotating, and the rotating speed of the inner cylinder exceeds a certain value, the flow pattern can be either laminar or turbulent Taylor-Couette flow. UV disinfection between concentric cylinders in laminar Poiseuille flow, turbulent flow and both laminar and turbulent Taylor-Couette flow was investigated experimentally and numerically. This is the first systematic study done on UV disinfection between concentric cylinders in all three flow patterns. The present work provides new experimental data for pathogen inactivation in each of the three flow patterns. In addition, the present study constitutes the first systematic numerical CFD predictions of expected inactivation levels. Proper operating parameters and optimum gap widths for different flow patterns are suggested. It is concluded that laminar Poiseuille flow provides inferior (small) inactivation levels while laminar Taylor-Couette flow provides superior (large) inactivation levels. The relative inactivation levels are: laminar Poiseuille flow < turbulent flow < laminar Taylor-Couette flow.
16
Schreier, Wolfgang. "UV-Strahlung und DNA-Schäden". Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-87818.
Testo completo
17
Nilsson, Henric. "UV-tork - analys av drift :". Thesis, Karlstads universitet, Avdelningen för maskin- och materialteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-14259.
Testo completo
18
Grant, Robert Wallace. "A UV Zeeman-effect polarizer". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24674.
Testo completoAbstract (sommario):
It is shown that light emitted by mercury vapour at 253.7 nm can be polarized by passing the light through mercury absorption gas embedded in a magnetic field which is transverse to the direction of propagation of the light. The absorption lines of the mercury are split by the Zeeman effect, so that the absorber has an absorption coefficient which depends on both the polarization and wavelength of the transmitted light.
A complete theory for the Hg²⁰² isotope is presented and the results are compared to measurements made with a natural mercury emitter and absorber. The observations are in qualitative agreement with the theory once isotope and hyperfine structure of the isotopes in natural mercury are included in the theory. Quantitative analysis was not possible because the emission line profiles could not be measured with the available equipment.Science, Faculty of
Physics and Astronomy, Department of
Graduate
19
Pinho, George Paul. "UV laser ablation of metals". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0016/NQ38265.pdf.
Testo completo
20
Forster, Piers Maxwell de Ferranti. "Measuring and modelling UV radiation". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384875.
Testo completo
21
Kantola, J. (Joni). "UV-absorboivat selluloosananokiteet kalvojen lisäaineena". Bachelor's thesis, University of Oulu, 2016. http://urn.fi/URN:NBN:fi:oulu-201605171790.
Testo completoAbstract (sommario):
Tämän työn tavoitteena oli tutkia UV-absorboivien selluloosananokiteiden valmistusta ja käyttöä kalvojen lisäaineena estämään UV-säteiden läpäisyä sekä toimimaan lujitteena kalvomateriaalissa. Työn kirjallisuuskatsauksessa etsittiin tietoa selluloosasta, selluloosananokiteistä, selluloosananokidekomposiittien ominaisuuksista sekä metallinanopartikkeleiden käytöstä kalvorakenteissa.
Työ koostui pääasiassa kokeellisesta osiosta, jossa valmistettiin perjodaattihapetuksen avulla UV-absorboivia selluloosananokiteitä, joita käytettiin polyvinyylialkoholifilmien lisäaineena. Työssä valmistettiin viisi kalvoa, joihin lisättiin erisuuruiset määrät selluloosananokiteitä. Kuudes valmistettu kalvo toimi vertailukohteena, ja tähän ei lisätty selluloosananokiteitä. Valmistetuista kalvoista mitattiin kalvojen vetolujuudet ja läpinäkyvyydet eli transmittanssit.
Valmistetuista kalvoista mitattiin vetolujuudet käyttäen kuitu- ja partikkelitekniikan laboratorion vetolujuuslaitteistoa. Läpinäkyvyys- eli transmittanssimittaukset mitattiin UV-Vis-spektrometrillä. Kalvomittausten lisäksi suoritettiin transmittanssi- ja absorptiomittauksia nanoselluloosaliuosnäytteistä, joiden avulla pystyttiin vahvistamaan kalvomittauksien tuloksia.
Mittaustuloksista havaittiin, että selluloosananokiteiden lisääminen kalvojen lisäaineeksi parantaa kalvojen mekaanisia ja optisia ominaisuuksia. Vetolujuusmittauksia tehdessä näytepalojen venymä kuitenkin vaihteli melko paljon jokaisen kalvon kohdalla, vaikka vetolujuuksien suuruuksissa ei tapahtunut merkittävää hajontaa. Tämä voi johtua mm. kalvojen valmistuksessa johtuneista virheistä. Näytepalojen rakenteeseen saattoi vaikuttaa heikentävästi se, että vakuumin avulla ei saatu aivan pienimpiä ilmakuplia poistettua tai koska alustalle valetut kalvot säilytettiin laboratoriokaapeissa, missä on mahdollista että kalvoihin pääsi pieniä määriä pölyä tms.
Tulokset olivat kuitenkin pääasiassa onnistuneet, kun niitä vertaillaan aikaisempiin tutkimuksiin. Selluloosananokiteiden käyttö esimerkiksi pakkausmateriaalien lisäaineena on tällä hetkellä suuren kiinnostuksen kohteena tutkijoiden keskuudessa, sillä niiden ympäristöystävällisemmät ja luonnolliset ominaisuudet ovat vahva haastaja raskaampien ja haitallisempien metallinanopartikkeleiden käytön korvaajaksi kalvomateriaalien lisäaineena. Tässä työssä käytettiin kuitenkin vain yhtä kalvomateriaalia, johon selluloosananokiteitä lisättiin, joten tuloksia ei voida yleistää niin, että selluloosananokiteiden lisääminen parantaisi kaikkien kalvomateriaalien ominaisuuksia.
22
Emmerson, Gregory Daniel. "Novel direct UV written devices". Thesis, University of Southampton, 2003. https://eprints.soton.ac.uk/42435/.
Testo completoAbstract (sommario):
This thesis reports a series of developments based on UV writing of novel waveguide structures. The first section is an investigation into the production of Direct UV-written channel waveguides on the perimeter of a cylindrical substrate. Cylindrical waveguides were produced using variants of the Modified Chemical Vapour Deposition (MCVD) and Flame Hydrolysis Deposition for the fabrication of thin films on either surface of the cylinder. Three layer, buried waveguide structures were produced using three techniques, and channel waveguides Directly UV-written into one of the samples. The second section concerns the simultaneous definition of channel waveguides and Bragg grating structures in planar substrates. This new process used two overlapped, tightly focused UV laser beams to generate a ~3μm writing spot with an interference pattern within the intensity profile. Translation of the writing spot with the power set to a continuous value averages out the effect of the interference pattern, defining channel waveguides. Modulation of the intensity of the writing spot in the fabrication process results in the definition of channel waveguides and Bragg gratings at the same time. The structure of the grating is defined by the precise motion and modulation of the writing spot, a function controlled by a computer and is not an absolute function of the interference pattern. Using this Direct Grating Writing technique, grating and channel structures were written into blank photosensitive 3-layer silica-on-silicon samples producing gratings with peak reflection intensities between OdB and >30dB. Bragg gratings with peak centre wavelength reflections spanning 488nm were written in a single fabrication run, all with equalised grating strengths. Direct Grating Writing was also used to produce a range of 2-dimensional planar structures including y-splitters and directional couplers. The gratings produced using this new technique were used to investigate sample photosensitivity and waveguide dispersion. Other results include; superimposed gratings, the superposition of a grating onto an etched structure and a Bragg grating based sensor
23
Adikan, Faisal Rafiq Mahamd. "Direct UV-written waveguide devices". Thesis, University of Southampton, 2007. https://eprints.soton.ac.uk/65507/.
Testo completoAbstract (sommario):
This thesis describes a series of experimental studies concerning waveguide structures based on the direct UV and direct grating writing fabrication techniques. The latter approach allows simultaneous definition of waveguide structures and Bragg gratings. The first result of this work describes the fabrication and characterisation of small angle X-couplers that exhibit low polarisation and wavelength dependence. Maximum and minimum coupling ratios of 95% (±0.8%) and 1.9% (±1%) respectively with typical excess loss of 1.0dB (±0.5dB) were recorded. Device modelling using Beam Propagation Method (BPM) and an analytical model showed good agreement with experimental results over a broad crossing angle and wavelength range. By introducing refractive index asymmetry in 2° X-couplers, it was possible to tune the response to give a 50:50 coupling ratio. Multiple UV exposure experiments investigated the 'proximity effect' and provided further proof of the ability of UV writing to produce raised waist index X-couplers. A first order Bragg grating electrically tunable via liquid crystal index modification with a maximum tunability of 141 GHz at 1562nm (TM polarised) and 114 GHZ at 1561.8nm (TE polarised) using electro-patterned ITO-coated glass electrodes is also presented. The 141GHz tuning range effectively covers up to five 25 GHz WDM channel spacing and was achieved with 170Vpp sinusoidal 1 kHz supply voltage. Hysteretic behaviour of the tuning curves was observed and is believed to be related to the dynamics of the disclination line formed along the waveguide axis with increase or decrease in supply voltage. Finally, a description of the successful demonstration of UV-written single channels, y-splitters, and Bragg gratings into a novel flat fibre substrate is provided. Utilising a series of Bragg gratings enabled assessment of the core layer uniformity and birefringence.
24
Ahmed, Masud Omar. "Teststation för industriella UV-celler". Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-165036.
Testo completoAbstract (sommario):
GE Healthcare Bio-Sciences AB in Umeå produce a variety of chromatography systems. One of the main components in chromatography is the UV module, which measure the light absorption of different wavelengths in the liquid being pumped through a cell. Currently at the Umeå site two types of UV-cells are produced; lab cells and industrial cells. The current test station for the industrial UV-cells is outdated, in disrepair and no longer supported. GE has developed a test station for the lab cells that evaluates UV and flow properties, the data is stored in GE’s own production database, Prodas. The aim of this work is to design a test station for industrial UV-cells to improve the quality of the cells. The primary goal is a test station that can measure pressure, flow and absorption. The secondary goal is to discover and if possible, implement solutions that will streamline and automate the test station. A prototype of a test station for industrial UV-cells based on that for lab cells has been developed. The solution consists of an adapter that links the light path from the monitor through the UV-cell to the detector. The test station can measure pressure, flow and absorption but can only perform absorption and leakage tests. Automation and efficiency have been accomplished in the form of scripts used to conduct absorption and leakage tests. The test station requires further development before it can be used in the production line.GE Healthcare Bio-Sciences AB i Umeå tillverkar ett flertal system, ett av systemen är vätskekromatografen. Vätskekromatografen är en kemisk separationsmetod som använder sig av en UV-monitor, UV-detektor och en UV-cell för att mäta absorptionen av en lösning och framta koncentrationen av det eftersökta ämnet. På anläggningen i Umeå tillverkas två typer av UV-celler; laborationceller och industriceller. För labbcellerna har GE utvecklat en teststation som testar och utvärderar UV och flödesegenskaper samt lagrar data i GE:s egen produktionsdatabas, Prodas. Den befintliga stationen för industriceller är äldre och omodern, en utveckling behövs för att upprätthålla högre kvalité. Syftet med detta projekt är att uppdatera teststationen för industriella UV-celler till samma nivå som stationen för laborationsceller. Det primära målet är att konstruera och designa en teststation för industriella UV-celler som kan mäta tryck, flöde och absorption. Det sekundära målet är att upptäcka och om möjligt verkställa lösningar som kommer effektivisera och automatisera mätningarna. En prototyp av en teststation för industriella UV-celler baserat på den för laborationceller har framtagits, och består av en adapterlösning som används för att sammanlänka ljusbanan från monitorn genom flödescellen till detektorn. Prototypen kan enbart utföra absorption och läckagemätningar. Automatisering och effektivisering har utförts i form av scripts som används för att genomföra absorptions och läckagemätning. Teststationen kräver fortsatt vidareutveckling innan den kan används i produktionslinjen.
25
Neto, Miguel Angelo da Costa. "Emissões UV em diamantes naturais". Master's thesis, Universidade de Aveiro, 1997. http://hdl.handle.net/10773/17469.
Testo completoAbstract (sommario):
Mestrado em FísicaNesta tese são estudados centros ópticos que aparecem na região UV do espectro electromagnético de um diamante natural tipo Ia. Longe de pretender ser um estudo pormenorizado e exaustivo desses centros ópticos, esta tese visa fundamentalmente o aprofundamento e respectiva aplicação de conhecimentos adquiridos ao longo da licenciatura e inestrado. No primeiro capítulo desta tese é apresentada uma descrição das principais propriedades fisicas dos diamantes, assim como a sua classificação. No segundo capítulo é feita a caracterização e distinção de defeitos e centros ópticos em diamantes. É ainda apresentada uma descrição da absorção e emissão da luz em centros ópticos, assim como uma breve enumeração dos principais centros ópticos observados em diamante. O tema principal do terceiro capítulo refere-se à interacção electrão-fonão. Neste capítulo são apresentadas algumas considerações teóricas e feitas aproximações que permitem explicar a forma como a luz se comporta em centros ópticos de um material cristalino. As técnicas experimentais de espectroscopia óptica utilizadas nesta tese são apresentadas no quarto capítulo. Aqui descrevemos o equipamento e os esquemas das montagens experimentais utilizadas em absorção e luminescência. No final do capítulo é feita uma descrição do efeito Raman, assim como do equipamento utilizado na obtenção dos respectivos espectros. No quinto e último capítulo são apresentados os dados e feita a análise dos resultados experimentais obtidos a partir das técnicas experimentais descritas no quarto capítulo. Começamos pelo estudo Raman do cristal, pois este permitiu confirmar que o diamante utilizado nos estudos é pouco homogéneo. Seguidamente, é feito o estudo da luminescência com o comprimento de onda de excitação e com a temperatura. Os resultados desses espectros Emissões UV em diamantes naturais vi Sumário levou-nos a obter a reconstrução das bandas vibrónicas dos centros ópticos em estudo. Além destes espectros, são ainda apresentados espectros de absorção e resolvidos no tempo, tendo estes últimos provado que os centros em causa têm um tempo de vida muito curto. Por último, são apresentadas as principais conclusões dos estudos efectuados e sugerem-se trabalhos futuros para melhor conhecimento dos centros ópticos estudados durante esta tese.
26
McGivney, Eric. "Comparison of UV-C and Vacuum- UV induced AOT on the acute mortality of microalgae". Thesis, KTH, Mark- och vattenteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171839.
Testo completoAbstract (sommario):
Advanced oxidation technology (AOT) has been used to destroy microorganisms in ballast water by breaking down the cell membranes. The primary objective of this study was to determine the effects of a ballast water treatment system that uses a combination of UV-C (λ=254 nm), Vacuum-UV (VUV; λ=185 nm) and photocatalytic titanium dioxide (TiO2) on a freshwater algae, Pseudokirchneriella subcapitata, and a marine algae, Tetraselmis suecica. The coupling of a semiconductor, such as TiO2, with a UV source is known as an advanced oxidative technology (AOT). To test the effects of TiO2 and wave length on algae, dose-response experiments were conducted to determine the species median lethal dose (LC50) for each of the following treatments: UV-light emitted at 254 nm (UVλ=254 nm), UV-light emitted at 254 nm in the presence of TiO2 (AOTλ=254 nm), and UV-light emitted at λ=254 nm (90 %) and 185 nm (90 %) in the presence of TiO2 (AOTλ=185 + 254 nm). In both species, TiO2 significantly increased mortality, most likely due to the biologically harmful radicals generated at the TiO2 surface. The addition of the 185 nm wavelength significantly increased cell mortality in P. subcapitata, but not in T. suecica. Across all three treatments, P. subcapitata was more sensitive than T. suecica. The secondary purpose of this study was to assess the applicability of ImageJ, an image analysis software, for highthroughput data to analyze the effectiveness of ballast water treatment. ImageJ has been used to rapidly and accurately perform cell Live/Dead analysis; however, several hurdles were identified.
27
Lani, Mohd Nizam. "Inactivation of Lysteria monocytogenes by pulsed UV illumination and photorepair recovery of UV-damaged cells". Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443144.
Testo completo
28
Devant, Ludovic. "Etude des mécanismes de vieillissement d'un caoutchouc EPDM (Ethylène Propylène Diene Monomer)". Thesis, Orléans, 2011. http://www.theses.fr/2011ORLE2067.
Testo completoAbstract (sommario):
Ce travail de thèse est consacré à l’étude du vieillissement UV d’un caoutchouc EPDM (éthylène propylène diène monomère) avec une attention spéciale sur les additifs du système de vulcanisation. Pour cela nous avons utilisé des techniques particulièrement adaptées à l’analyse de surface telles que le ToF-SIMS, l’XPS, l’ATR-FTIR, le MEB-EDX et l’AFM. Dans un premier temps nous avons pu déterminer la composition chimique de la surface du caoutchouc EPDM vulcanisé à l’état initial. Nous avons pu identifier les sous-produits de vulcanisation et déterminer de manière qualitative leur répartition en surface. Les profils en profondeur ToF-SIMS ont permis de mettre en évidence une couche d’enrichissement en additifs à le surface du caoutchouc dont l’origine pourrait provenir de leur migration par cristallisation ou « effet bloom » par vulcanisation. Dans la seconde partie, nous avons étudié l’effet du vieillissement artificiel SEPAP sur le caoutchouc et sur les additifs. Nos résultats montrent que la surface du caoutchouc ainsi que les deux accélérateurs de vulcanisation, le MBTS (2,2’-Dithiobis(benzothiazole)) et le ZBPT (Zinc O, O-Dibutylphosphorodithioate) subissent des changements chimiques et morphologiques profonds caractérisés par une oxydation chimique et une dégradation structurale. Les études cinétiques ont montré que les changements chimiques les plus importants étaient observés pendant les 100 premières heures. Nous avons examiné un caoutchouc industriel, actuellement utilisé dans l’étanchéité de carrosserie, afin de mieux comprendre le comportement des agents de mise en oeuvre à l’état initial et au cours du vieillissement. Ces agents de mise en oeuvre jouent un rôle clé dans la composition chimique du caoutchouc à l’état initial malgré la faible quantité incorporée. Nous avons montré que ces composés recouvrent la surface et forment une couche épaisse d’environ 500 nm, très résistante au vieillissementThis thesis is devoted to the study of UV aging of an EPDM rubber with particular emphasis on additives involved invulcanization. For this purpose, we use techniques suitable for surface analysis such as ToF-SIMS, XPS, ATR-FTIR, SEMEDXand AFM. We first determine the initial chemical composition of the surface of the EPDM rubber. We identify the by-products of vulcanization and qualitatively determine their distribution on the surface. The ToF-SIMS depth profiles exhibit a layer enriched in additives on the surface of the rubber due to migration by crystallization or by the “bloom effect” after vulcanization. In addition, images from 3D profiles show that some of these additives are adsorbed on the no-black fillers. In the second part, we study the effect of artificial aging on the rubber and the additives. Our results indicate that both the surface of the rubber and the two rubber accelerators, MBT and ZBPT, undergoes significant chemical and morphological changes characterized by chemical oxidation and structural degradation. Our Kinetic studies show that the most important chemical changes take place during the first 100h. The final chapter is devoted to the study of industrial rubber, currently used in vehicle body seals, and discusses on understanding of the behavior of the processing agents in the initial state and during aging. These agents play a key role in the chemical composition of the rubber in the initial state, despite the small amounts incorporated. We show that these compounds cover the surface and form a layer about 500 nm thick, very resistant to aging
29
Olsson, Sara. "Enhancing UV-protection of clear coated wood by utilizing reactive UV-absorber and epoxyfunctionalized soybean oil". Licentiate thesis, KTH, Ytbehandlingsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92220.
Testo completoAbstract (sommario):
This work presents the development of a new pretreatment for clear coated wood, that aims to increase the photoprotection of exterior wood products, and at the same time make the system more environmentally friendly. The pretreatment comprises the reactive UV absorber 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP), which has a primary epoxy group that can be covalently attached to the hydroxyl groups of the wood substrate. This reactant is accompanied by renewable epoxy functionalized soybean oil (ESBO), which contains a secondary epoxy group that also has the ability to react with the substrate and that promotes the compatibility between the two reactants. The ESBO further seems to have the advantage of increasing the flexibility of the pretreated veneers as well as decreasing the amount of water in the cell wall of the wood. The study was performed in two parts where the first part focused solely on the development and performance of the pretreatment, whereas the second part used the knowledge gained from part one to evaluate the pretreatment in combination with an acrylic clear coating. Grafting reactions were performed on thin wood veneers heated in solvent. In the first part the reaction parameters, temperature and reaction time, were varied to study their effects on the final properties of the pretreatments. The veneers where then analyzed using FTIR to determine if grafting was achieved. Results show that grafting was successful for reactions performed at temperatures above 90 °C. For part two, grafting was successful for both the boil- and dip process, indicating that a considerably shorter reaction time can be used. Samples from both part one and two where then exposed to accelerated ageing and the color change was measured to estimate the UV-resistance. The first part showed improved UV-resistance for some of the pretreatments, whereas the second part was more difficult to evaluate due to the top coat, but a slight improvement can be seen for samples using the pretreatment. A positive result for part two is also that the pretreatment do not appear to affect the adhesion between the substrate and the top coat. It is hence concluded that the proposed pretreatment is a possible way of increasing the photostability of exterior wood.Detta arbete beskriver utvecklandet av en ny förbehandling för klarlackat trä som syftar till att öka UV-beständigheten av träprodukter för utomhusbruk. Arbetet syftar även till att utveckla systemet till att bli miljövänligare än nuvarande liknande produkter på marknaden. Förbehandlingen utnyttjar primära epoxidgrupper hos den reaktiva UV-absorbenten 2-hydroxy-4(2,3-epoxypropoxy)-bensofenon (HEPBP) för att skapa kovalenta bindningar till hydroxylgrupper hos träet. Den andra komponenten i systemet är förnyelsebar epoxiderad sojaolja (ESBO) innehållande sekundära epoxidgrupper som även dessa kan binda kovalent till träytan, samt gynna kompatibiliteten mellan de två reaktanterna. Oljan verkar dessutom öka flexibiliteten av förbehandlingen, samtidigt som den minskar mängden vatten som tränger in i cellväggen. Studien utfördes i två delar där den första delen fokuserade enbart på att utveckla förbehandlingen, medan den andra delen utnyttjade information från den första delen för att utvärdera funktionen av förbehandlingen i kombination med en akrylatbaserad klarlack. Ympningsreaktionerna utfördes på tunna träfaner i uppvärmd lösning. I första delen studerades hur temperatur- och reaktionstidsförändringar påverkar den slutgiltiga prestationen av förbehandlingen, och FTIR användes då för att verifiera ympningen. Resultaten visar att ympningen var lyckad för reaktioner utförda vid reaktionstemperaturer över 90 °C. För del två ansågs ympningen lyckad för både dopp- och kokreaktionen, vilket tyder på att betydligt kortare reaktionstider skulle kunna användas. Prover från både del ett och två utsattes sedan för accelererad åldring där färgförändringen av proverna mättes för att uppskatta UV-resistensen av behandlingarna. Första delen visade på ökad UV-beständighet för vissa av behandlingarna. Del två var dock svårare att utvärdera till följd av klarlacken, men en liten förbättring kan noteras för prover som är förbehandlade. En positiv notering från del två är även att adhesionen mellan klarlacken och träytan inte verkar ha påverkats av förbehandlingen. Med detta som grund dras slutsatsen att den föreslagna förbehandlingen kan förbättra UV-resistensen av klarlackat trä för utomhusbruk.
QC 20120330
30
Bagheri, Mehdi. "Computer-aided study of Vacuum-UV/UV process for removal of organic pollutants from water supplies". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/57463.
Testo completoAbstract (sommario):
Water authorities are increasingly worried about the occurrence of organic micropollutants (e.g., algal toxins, endocrine disrupting compounds, pesticides, industrial chemicals, taste and odor compounds) in water supplies. Removal of organic micropollutants (OMPs) from water is cost-prohibitive, particularly for small and remote communities. Vacuum-UV/UV process, an incipient catalyst/chemical-free advanced oxidation process (AOP), is potentially a cost-effective solution for removal of harmful micropollutants from water.
The main objective of this thesis was to investigate the feasibility of VUV/UV process for the removal of OMPs using a comprehensive computational fluid dynamics (CFD) analyzes. The developed model involved simultaneous resolution of the local transfer equations of momentum, mass, and radiative energy (for UV and VUV radiations), along with a complex kinetic scheme with more than 50 reactions. Given the importance of 185 nm and 254 nm emissions for the accurate modeling of the VUV/UV process, a new experimental method for measuring VUV and UV emissions of the mercury lamps was proposed. To assess the CFD model, VUV-induced degradation of model pollutants (atrazine, p-CBA) in ultrapure water samples was investigated under laminar flow conditions utilizing an axisymmetric laboratory-scale reactor. Afterwards, using an asymmetrical pilot-scale VUV/UV reactor, experimental validation of the CFD model was conducted for simulating the degradation of model pollutants (atrazine, 1,4-dioxane) in synthetic and natural contaminated waters under turbulent flow regime. Comparison of the modeling and experimental data indicated that the developed CFD model was able to predict successfully the degradation rate of target pollutants in the analyzed reactors. In addition, the proposed model showed to predict well the impact of the flow rates, and water matrix (NOM and alkalinity) on target pollutants degradation with less than 3 % average absolute relative deviation (AARD%). Relying on the insights gained by CFD analysis (e.g., knowing the critical role of pollutant mass transfer on the AOP performance of VUV systems), an improved VUV/UV process was developed through retrofitting baffles within the reactor. When compared the pollutant degradation and energy consumption of VUV/UV and H₂O₂/UV processes, superior performance of the improved VUV/UV process was observed.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
31
Chintalapati, Pranav Sankar. "Degradation of cyanobacterial toxin microcystin-LR using UV/vacuum-UV advanced oxidation for drinking water treatment". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63028.
Testo completoAbstract (sommario):
Cyanobacterial blooms have been increasing in magnitude and frequency around the world and studies have concluded that climate change, population growth, and industrial development will accelerate this phenomenon. The presence of cyanobacterial blooms in drinking water sources is a concern due to the production of cyanobacterial toxins, which are known to damage internal organs and disrupt nervous system functions. Shallow surface water sources for small water systems are at a greater risk of eutrophication and small, remote communities often lack the resources and infrastructure for adequate treatment. In conventional water systems, instances of cyanobacterial blooms are typically addressed by chemical addition. However, many remote communities are difficult to access and are unable to maintain a consistent supply of chemical oxidants.
This study investigated the capability of ultraviolet radiation at 254 nm and 185 nm wavelengths (UV/Vacuum-UV) to degrade microcystin-LR (MC-LR), one of the most commonly occurring and toxic cyanobacterial toxins. Results showed that substantial toxin removal could be achieved solely by direct photolysis with 254 nm. The addition of 185 nm increased MC-LR degradation through advanced oxidation by hydroxyl radicals (•OH). The presence of alkalinity and organic matter (DOC) reduced MC-LR degradation by scavenging •OH. DOC also absorbed 254 nm and 185 nm, requiring additional irradiation time to achieve a target UV dose. Chloride scavenged •OH, but in a reversible reaction, resulting in minimal impact on MC-LR degradation. The order of impact on MC-LR degradation by these common water constituents was DOC>Alkalinity>Chloride. In natural water with a complex matrix, MC-LR could be degraded from a typical concentration (15 µg/L) to below detection (<0.5 µg/L) with a UV254 fluence of 200 mJ/cm2. The presence of cyanobacterial cells impeded MC-LR degradation by adding turbidity to samples, absorbing 254 nm photons and scavenging •OH. However, substantial MC-LR degradation could still be achieved in the presence of cyanobacterial cells. UV/Vacuum-UV appears to be a promising chemical-free technology that is capable of MC-LR degradation in a variety of water conditions, and may be a suitable treatment option for small, remote communities.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
32
Sarrut, Morgan. "Optimisation de méthodes bidimensionnelles en ligne LCxLC-UV/MS et LCxSFC-UV pour l’analyse d’échantillons complexes". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1189/document.
Testo completoAbstract (sommario):
La chromatographie en phase liquide bidimensionnelle « comprehensive » en ligne (LCxLC) est une technique à très haut pouvoir de séparation. Après avoir établi son intérêt mais aussi les enjeux liés au développement de méthodes et les conditions expérimentales utilisées, une attention particulière est portée à l'optimisation des méthodes en LCxLC. Une procédure d'optimisation basée une méthode « Pareto-optimal » est décrite. Les conditions optimales prédites sont ensuite appliquées à la séparation RPLCxRPLC d'un mélange complexe de peptides et comparée avec la 1D-RPLC en termes de capacité de pics, temps d'analyse et facteur de dilution démontrant l'avantage fournit par la RPLCxRPLC. L'optimisation d'une méthode HICxRPLC-UV/MS en ligne permettant la caractérisation exhaustive d'un anticorps conjugué est réalisée soulignant, entre autres, la grande complémentarité entre les différents modes de détection employés en 1D et 2D.Enfin, la possibilité de développer un couplage RPLCxSFC est explorée dans le but d'augmenter l'espace de séparation pour des composés neutres. La méthode RPLCxSFC optimisée est comparée avec une séparation RPLCxRPLC optimisée pour l'analyse d'une bio-huile montrant qu'elle peut-être considérée comme une alternative crédible pour la séparation de tels échantillonsComprehensive two-dimensional liquid chromatography is a powerful but complex separative technique. After detailing the interest of such a technique, the method development issues and the experimental conditions employed throughout this work, a particular attention is paid to the optimization of LCxLC methods. Accordingly an optimization procedure based on Pareto-optimal method is described. The predicted optimal conditions are then applied to experimental RPLCxRPLC separations of complex samples of peptides and compared with 1D-RPLC in terms of peak capacity, analysis time and sensitivity clearly showing the advantage of RPLCxRPLC approach.The optimization of a HICxRPLC-UV/MS method for the exhaustive characterization of an antibody-drug conjugate is achieved highlighting the high complementarity of the different detection modes used both in 1D and 2D. Finally, a proof of concept concerning the implementation of RPLCxSFC coupling is achieved with the aim of increasing the separation space coverage for neutral compounds. The optimized RPLCxSFC separation is then compared with an optimized RPLCxRPLC approach for the analysis of a bio-oil sample showing that RPLCxSFC is a credible alternative for the separation of such a sample
33
Klein, Fátima Rosane Schuquel. "Alterações bioquímicas em espécies do gênero Alternanthera quando expostas à radiação UV-B e UV-C". Universidade Federal de Pelotas, 2014. http://repositorio.ufpel.edu.br/handle/ri/2008.
Testo completoAbstract (sommario):
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Previous issue date: 2014-02-21The knowledge about ultraviolet (UV) effects in medicinal plants is still limited when compared with what is already known about other environmental factors. To investigate this issue we carried out two experiments: the first aimed to study the production of betalains, total flavonoid, and antioxidant activity in plants of Alternanthera sessilis, Alternanthera brasiliana, Alternanthera tenella, and Alternanthera philoxeroides, which were exposed to UV-B radiation (280-315 nm) for different periods; the second performed the same analyses, adding the investigation of the antioxidant enzymes in A. sessilis, A. brasiliana, and A. philoxeroides, submitted to UV-C (100-280 nm) for different periods of exposure. In the first experiment, the plants grown for 50 days in greenhouse were exposed to different UV-B irradiation periods (0, 2, 4, 6, and 8 hours). The collections were conducted in two periods, immediately after each exposure time (0h) and after 24 hours, to view a possible recovery. During the period inside the greenhouse, the plants remained under natural light. The experimental design was completely randomized, in 4 x 5 x 2 factorial scheme with five replicates by treatment, each one represented by a plant. Among the species studied, A. sessilis showed higher levels of total betacyanins, betaxanthin, flavonoids, and greater antioxidant capacity compared to other species throughout the period of exposure to radiation. We observed that in the species A. sessilis and A. brasiliana the recovery time favored an increase in the production of these compounds. The species A. tenella and A. philoxeroides showed no increase in the production of their metabolites, after UV-B radiation exposure. A randomized experiment in factorial design 3 x 5 was conducted to analyze the effects of UV-C radiation with three species A. sessilis, A. brasiliana, and A. philoxeroides for times intervals of 0, 5, 10, 15, and 20 min, with five replicates for treatment. A. sessilis showed a higher increase in metabolites under UV-C radiation between 10 and 12 minutes of exposure; in A. brasiliana it was observed after 16 minutes of exposure. The species A. philoxeroides showed no increase in its content after irradiation, remaining equal to control. For the activity of the enzyme superoxide dismutase (SOD), the species showed no significantly differences, but for catalase (CAT) and ascorbate peroxidase (APX) showed greater activity. An increase in malondialdehyde (MDA) content under UV-C radiation was viewed in A. philoxeroides and A. sessilis. In this experiment it was observed that both radiations caused changes in the content of total betacyanins, betaxanthin, and flavonoids in the species A. sessilis and A. brasiliana, and UV-C radiation changed enzymatic activity only in the species A. philoxeroides. These changes depend on the time exposure to radiation and the defense mechanisms triggered.
Ainda é limitado o conhecimento dos efeitos da radiação ultravioleta (UV) em plantas medicinais quando comparados com o que já se conhece sobre outros fatores ambientais. Para investigar essas foram realizados dois experimentos: o primeiro com o objetivo de estudar a produção de betalaínas, flavonoides totais e atividade antioxidante em plantas de Alternanthera sessilis, Alternanthera brasiliana, Alternanthera tenella e Alternanthera philoxeroides expostas por diferentes períodos à radiação UV-B (280-315 nm) e, no segundo foram realizadas as mesmas análises, sendo, nesse caso investigada também a resposta de enzimas antioxidantes em A. sessilis, A. brasiliana e A. philoxeroides submetidas a diferentes tempos de exposição à UV-C (100-280 nm). No primeiro experimento, plantas cultivadas há 50 dias em casa de vegetação foram expostas a diferentes tempos de radiação UV-B (0, 2, 4, 6 e 8 horas). As coletas foram realizadas em dois períodos, imediatamente após cada tempo de exposição (0h) e após 24h dos mesmos, para visualizar uma possível recuperação. Até a realização da segunda coleta as plantas permaneceram sob iluminação natural, em casa de vegetação. O delineamento experimental foi inteiramente ao acaso em esquema fatorial 4 x 5 x 2 com 5 repetições por tratamento, sendo cada uma representada por uma planta. Dentre as espécies em estudo, A. sessilis foi a que apresentou maior teor de betacianinas totais, betaxantina, flavonoides e maior poder antioxidante quando comparada com as demais espécies em todos os tempos de exposição à radiação. Nas espécies A. sessilis e A. brasiliana foi observado que o tempo de recuperação favoreceu o aumento da produção desses compostos. As espécies A. tenella e A. philoxeroides não apresentaram incremento nos seus metabólitos após exposição à radiação UV-B. Para analisar os efeitos da radiação UV-C foi delineado um experimento inteiramente ao acaso em esquema fatorial 3 x 5, com três espécies (A. sessilis, A. brasiliana e A. philoxeroides) em cinco tempos de radiação (0, 5, 10, 15 e 20 min), com cinco repetições por tratamento. Os resultados dos metabólitos estudados diante da radiação UV-C demonstraram que houve maior incremento destes compostos em A. sessilis, entre 10 e 12 minutos de exposição e em A. brasiliana após 16 minutos de exposição. A espécie A. philoxeroides não apresentou incremento do seu conteúdo depois de irradiadas mantendo-se iguais ao controle. Para a atividade da enzima SOD (Superóxido dismutase), as espécies não apresentaram diferenças significativas enquanto para CAT (Catalase) e APX (Ascorbato peroxidase), A. philoxeroides mostrou maior atividade. Aumento do conteúdo de MDA (malondialdeído) foi verificado em A. philoxeroides e A. sessilis diante da radiação UV-C. Nas condições deste experimento observou-se que ambas as radiações promovem mudanças no conteúdo de betacianinas totais, betaxantinas, e flavonoides nas espécies A. sessilis e A. brasiliana e que a radiação UV-C altera a atividade enzimática somente na espécie A. philoxeroides.Estas mudanças dependem do tempo de exposição e dos mecanismos de defesa acionados diante das radiações.
34
Narayan, Vicrant S. "HPLC analysis of nucleotides". Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/104440/1/Vicrant_Narayan_Thesis.pdf.
Testo completoAbstract (sommario):
This project developed a novel hydrophilic interaction chromatography method for the detection and identification of nucleotides. The method was validated by testing biological specimens; adult and neonatal saliva, and red and white blood cell extracts. The project discovered an interesting difference between the adult and neonatal saliva specimens. The neonatal saliva contained 5 additional nucleotides and the nucleotides were present in greater concentrations, when compared to the concentrations in adult saliva. With further optimisation this method may be applied to testing in Pathology services and would facilitate the diagnosis of metabolic diseases that affect nucleotides.
35
Tjörnhammar, Staffan. "Pulsed Yb:KYW laser and UV generation". Thesis, KTH, Laserfysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-51595.
Testo completoAbstract (sommario):
In this master thesis project, a pulsed UV laser was designed and constructed. Also, the effects of absorption in a volume Bragg grating were investigated. The laser was diode pumped and constructed with Yb:KYW as gain medium. The lasing was at a wavelength of 1029.2 nm with a spectral bandwidth of 0.23 nm, locked by a volume Bragg grating that was used as input coupler for spectral control. Passive Q‑switching was used to generate pulses by placing a Cr:YAG saturable absorber inside the cavity. The laser generated radiation with a maximum peak power of 3.8 kW at an average power of 0.35 W, a repetition rate of 4 kHz and a pulse width of 16 ns. The maximum average power was 1.3 W with a peak power of 2 kW at a repetition rate of 20 kHz and with a pulse width of 20 ns. Through extra‑cavity second harmonic generation using an LBO crystal, green light at a wavelength of 514.7 nm was generated. The maximum average power was 130 mW with an optical conversion efficiency from the fundamental of around 10 %. Then, the second harmonic and the fundamental wave were mixed to generate UV light, at a wavelength of about 343 nm, by using a second LBO crystal. The maximum average power of UV was about 23 mW with an optical efficiency, with respect to the green, of approximately 20 %. One limitation of the laser was that the Cr:YAG was bleached not only by the circulating laser field, but also by remaining pump light. This resulted in decreasing peak power with increasing pump power, thus limiting the nonlinear conversion efficiencies. Thermal fracture of the Cr:YAG was a limiting factor for the intra-cavity average power, while burning of the coating on the Yb:KYW crystal limited the maximum peak power. The effects on a laser when using too high power for the level of absorption in a volume Bragg grating were also investigated. The effects of both resonant and non-resonant beams were investigated. Since the intensity of a resonant beam decreases approximately exponentially in a volume Bragg grating, due to absorption, an uneven temperature distribution along the propagation axis is formed. This results in different thermal expansion and hence, results in a longitudinal chirp of the grating. The chirp caused a decrease in both reflectivity and spectral selectivity. The reflectivity of the particular grating used in these experiments decreased from 99.4 % to 93 %. In addition, it was experimentally shown that if a volume Bragg grating absorbs a non-negligible amount of a non-resonant beam, the thermal load will deform the volume Bragg grating. Therefore, it is not suitable to use such a grating the as input coupler of a laser cavity.I detta examensarbete utformades och konstruerades en pulsad UV-laser. Dessutom undersöktes effekterna av absorption i ett volymbraggitter. Som laserkristall användes Yb:KYW vilken pumpades med en diodlaser. Lasring skedde vid 1029,2 nm med en bandbredd av 0,23 nm genom att ett volymbraggitter användes som inkopplingsspegel för att kontrollera spectrumet. Pulser generades genom passiv Q-switching med en Cr:YAG som mättnadsbar absorbator inne i kaviteten. Den maximala toppeffekten var 3,8 kW vid 0.35 W medeleffekt, 4 kHz repetitionsfrekvens och en pulsbredd på 16 ns. Den maximala medeleffekten var 1.3 W med en toppeffekt på 3,8 kW, 20 kHz repetitionsfrekvens och en pulsbredd på 20 ns. Genom frekvensdubbling i en LBO kristall genererades grönt ljus vid våglängden 514,7 nm. Den maximala medeleffekten var 130 mW med en optisk verkningsgrad från den fundamentala våglängden på 10 %. Sedan blandades det infraröda och det gröna ljuset i en andra LBO kristall för att generera UV-ljus, vid en våglängd om 343 nm. Den högsta medeleffekten av UV var cirka 23 mW med en optisk verkningsgrad, med avseende på det gröna ljuset, på ungefär 20%. En begränsning av laser var att Cr:YAG kristallen blektes inte enbart av lasern utan även av pumpen. Detta resulterade i fallande toppeffekt med ökande pumpeffekt, vilket begränsade effektiviteten i den ickelinjära konverteringen. Termisk fraktur på Cr:YAG kristallen var en begränsande faktor för cirkulerande medeleffekten i kaviteten, medan brännskador på Yb-kristallens antireflexbehandling begränsade toppeffekten. Effekterna i en laser vid användning av en alltför hög effekt i förhållande till nivån av absorption i ett volymbraggitter studerades också. Effekterna av både resonanta och ickeresonanta strålar undersöktes. Eftersom intensiteten av en resonant ståle minskar ungefär exponentiellt i ett volymbraggitter kommer temperaturen, på grund av absorption, fördelas ojämnt i propageringsriktningen. Detta resulterar i olika termiska expansion med en längsgående varierad gitterperiod som följd. Detta orsakar en minskning utav både reflektiviteten och den spektrala selektiviteten. Reflektiviteten i gittret som användes i dessa experiment minskade från 99,4 % till 93 %. Dessutom visades det experimentellt att om ett volymbraggitter absorberar en icke försumbar del av en ickeresonant stråle kommer värmebelastning att deformera volymenbraggittret. Därför är det inte lämpligt att använda ett sådant gitter som inkopplingsspegel i en laser.
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Borgström, Roger, e Daniel Enesten. "Uv-ljus som vattenrening i kylanläggning". Thesis, Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-19096.
Testo completoAbstract (sommario):
I det här projektet har uppgiften varit att rena vattnet i Aqua Interiör i Laholms egen tillverkade vattenmöbel med hjälp av uv-ljus. Dessa möbler hyr de ut till kunder för att kunna få ett lagom kallt vatten med eller utan kolsyra. Vattenmöblerna är direkt kopplade till det befintliga vattensystemet. Ett problem som de tidigare haft är att de inte kunnat ha sina möbler på sjukhus eftersom möblens beskaffenhet medför en ökad bakteriehalt i vattnet.Denna bakteriehalt kommer dock inte upp till den gräns som livsmedelverkets satt som icke tjänligt. På sjukhus finns ett högre krav på vattnets kvalité där inga anmärkningar får finnas på vattnet. Vid uv-bestrålning hoppas man att detta problem kommer att lösas.Det har tagits fram en reaktor där vattnet uv-bestrålas i en spiral gjord av kvartsglas. Ett styrkort har tagits fram för att styra bestrålningen av vattnet och att ha kontroll på att inga problem med bestrålningen uppkommer.En display med touchfunktion har använts för att på ett snyggt sett presentera viktig information om lampans status och temperatur inne i reaktorn. Detta för att serviceman på vattenmöbeln ska få information på om lampan behöver bytas eller inte. En inloggning i systemet skapades för att förvissa sig om att inga obehöriga skulle ha möjlighet att radera den loggdata som skapas. Med touchdisplayen har man fått en gedigen känsla av kvalite och ny teknik.Användningen av detta uv-filter har resulterat i att vattnet har renats med ett positivt resultat. Förhoppningen är att en vidare utveckling på det här projektet kommer leda till en färdig produkt som kommer säljas/uthyras av Aqua Interiör i Laholm.The objective with this project has been to purify water in the Aqua Interiör in Laholm proprietary water furniture using uv-light. These furnitures are rent out to customers to get moderately cold water, with or without sparkling. The water furnitures is directly connected to the water system. A problem with the water furniture is that it is not suitable for hospitals because there is an increased bacterial content in the water, however, below the prescribed limits. In hospitals there is a higher requirement for water quality. The objective with the uv-radiation is to solve this problem. A reactor has been developed in which the water is uv-radiated in a spiral made of quartz glass. A control system controls the radiation of the water and that no problem occurs during the radiation.A display with touch-function has been used to get an attractive way to present important information about lamp status and temperature inside the reactor. This is how the service personnel receive information on the lamp if it needs replacing or not. A log of the system was created to ensure that no unauthorized person would be able to delete the log data that is created. The touch-display made it a solid feeling of quality and new technology.The use of the uv filter has resulted in a positive result, with purified water. An ambition is that further development of this project will lead to a finished product that will be sold / out rented by Aqua Interiör i Laholm .
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Bykov, Vladimir J. "UV-induced DNA damage in humans /". Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3345-6/.
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Wissen, Matthias. "Thermisches Nanoimprint in UV vernetzende Fotolacke". Tönning Lübeck Marburg Der Andere Verl, 2007. http://d-nb.info/988176343/04.
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Taylor, Tammye L. "UV photochemistry of synthetic model peptides". Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/26966.
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Greuters, Jako. "UV laser micromachining of photonics materials". Thesis, University of Hull, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431044.
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Houghton, Steven. "Hyperbranched polyesters in UV-curable coatings". Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274354.
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Erdemli, Ӧmer Can. "UV stabilisation of poly(ethylene terephthalate)". Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27455.
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Waldron, Daniel E. "Instrument design in UV polarised spectroscopy". Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/51549/.
Testo completoAbstract (sommario):
Biological macromolecules are becoming increasingly important as a target for pharmaceutical research. Structural examination of this class of compounds is vital, both in terms of understanding the three-dimensional structures these molecules form as well as for quality control of bio-pharmaceutical products. UV polarised spectroscopy, such as circular dichroism (CD) is a powerful tool for this form of analysis, rapidly providing the user with structural information on the sample. The ease of data analysis combined with its non-destructive nature make UV polarised spectroscopy an ideal tool for this purpose. However, limitations in the current instrumentation, especially in terms of sample handling have placed significant barriers in the way of fully realising the potential of these techniques. To address the weaknesses of the currently available UV polarised spectroscopy accessories, new devices have been designed and tested to increase the utility of such techniques. A low volume capillary sample holder has been developed which significantly reduces the sample requirements for circular dichroism without loss of signal quality. This advance has been coupled with an HPLC auto-sampler to create a device that can process 96-well and in some cases 384- well plates. This device opens up a host of new applications for polarised UV spectroscopy, including refolding screening as well as freeing up user time. Additionally, a high precision demountable micro scale cuvette has been developed that reproducibly assembles to the same path length every time. The percentage error of path-length for this new cuvette is of the same order as currently commercially available 1 mm cuvettes. This new accessory should prove highly advantageous for the bio-pharmaceutical industry, as it allows accurate path-length CD analysis for high concentration samples. Additionally, the first confirmed linear dichroism (LD) spectrum of a bacterium and flagella are reported, opening up the potential for real time UV spectroscopic analysis of living bacteria. By using the work contained within this thesis, it should be possible to construct a new form of high path-length accuracy, low volume, multiple-sample UV polarised spectroscopy accessory that could be used for both CD and LD analysis.
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Weldegebriel, Amos. "A UV detector for microfluidic devices". Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/17626.
Testo completoAbstract (sommario):
Master of ScienceDepartment of Chemistry
Christopher T. Culbertson
Chemical separation involves selective movement of a component out of a region shared by multiple components into a region where it is the major occupant. The history of the field of chemical separations as a concept can be dated back to ancient times when people started improving the quality of life by separation of good materials from bad ones. Since then the field of chemical separation has become one of the most continually evolving branches of chemical science and encompasses numerous different techniques and principles. An analytical chemist’s quest for a better way of selective identification and quantification of a component by separating it from its mixture is the cause for these ever evolving techniques. As a result, today there are numerous varieties of analytical techniques for the separation of complex mixtures. High Performance Liquid Chromatography (HPLC), Gas Chromatography (GC), Capillary Electrophoresis (CE) and Gel Electrophoresis are a few out of a long list. Each these techniques manipulates the different physical and chemical properties of an analyte to achieve a useful separation and thus certain techniques will be suited for certain molecules. This work primarily focuses on the use of Capillary Electrophoresis as a separation technique. The mechanism of separation in Capillary Zone Electrophoresis and principles of UV detection will discussed in chapter one. Chapter two contains a discussion about the application of Capillary Electrophoresis (CE) on microfluidc devices. This will include sections on: microfabrication techniques of PDMS and photosensitized PDMS (photoPDMS), a UV detector for microfluidic devices and its application for the detection of wheat proteins. In Chapter three we report the experimental part of this project which includes; investigations on the effect of UV exposure time and thermal curing time on feature dimensions of photoPDMS microfluidic device, investigations on the injection and separation performances of the device, characterization of a UV detector set up and its application for the separation and detection of wheat gliadin proteins. The results of these investigations are presented in chapter four.
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Marlow, Gregory. "Week 08, Video 04: UV Unwrapping". Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/digital-animation-videos-oer/58.
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Marlow, Gregory. "Week 08, Video 05: UV Unfold". Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/digital-animation-videos-oer/59.
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Marlow, Gregory. "Week 08, Video 06: UV Export". Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/digital-animation-videos-oer/60.
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Touré, Mamadou Lamine. "Exposition UV spectrale : instrumentation et modélisation". Université Joseph Fourier (Grenoble), 2003. http://www.theses.fr/2003GRE10034.
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Houët, Mickaël Brogniez Colette. "Spectroradiométrie du rayonnement UV au sol". [S.l.] : [s.n.], 2003. http://www.univ-lille1.fr/bustl-grisemine/pdf/extheses/50376-2003-149-150.pdf.
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Cui, Yong. "UV pumped holosteric optical parametric oscillator". Thesis, University of St Andrews, 1993. http://hdl.handle.net/10023/14889.
Testo completoAbstract (sommario):
The all-solid-state (or "holosteric") optical parametric oscillator has resulted from the recent development of diode-laser-pumped solid-state lasers and from recent advancements in new optically nonlinear materials. As a result, all-solid-state sources of widely tunable (ultraviolet - visible - near infrared) coherent radiation are now possible by using the radiation from diode-laser-pumped solid-state lasers, either directly or after frequency conversion, to pump optical parametric oscillators. Such devices can be made compact, efficient and reliable. The work described in this thesis explores the feasibility of obtaining widely tunable radiation from such devices, with particular reference to low threshold, high efficiency operation, so requiring only modest energies (1 mJ in ultraviolet) from the pump source. In particular, a frequency tripled or frequency quadruped Nd:YAG laser pumped by pulsed, GaAlAs diode laser bars has been used as the pump source, and lithium triborate has been used as the nonlinear medium in the optical parametric oscillator. Two geometries of lithium triborate crystals have been investigated as the nonlinear medium. One was cut for a type II non-critical phase matching geometry, while the other was cut for a type I critical phase matching geometry. The oscillator cavities were designed for optimum focusing and mode matching aiming for operation with a low pump energy through the use of tightly focused pump radiation. The ultraviolet pump source was based on a Q-switched diode-laser-pumped Nd:YAG laser which generated pulses at 1.064 mum with energy 10 mJ and duration around 10 ns. These were then frequency up-converted to the UV at 355 nm or 266 nm, so as to be suitable for pumping the parametric oscillators. Generally, an overall conversion efficiency from 1.064 mum to 355 nm of >30% was obtained using the nonlinear materials potassium titanyl phosphate and lithium triborate for second harmonic generation and sum-frequency mixing respectively. For conversion to 266 nm, an overall efficiency of > 18 % was obtained using the nonlinear materials KTP and BBO for two step second harmonic generation. In the experimental investigations of the all-solid-state lithium triborate optical parametric oscillator pumped at 355 nm a low oscillation threshold was obtained in the type II non-critical phase matching geometry (around 0.2 mJ) and pump depletions of 50 % were obtained at around six times threshold. This device could be temperature tuned (20 - 200 °C) from 457 to 481 nm (signal wave) and 1.6 to 1.35 mum (idler wave). Optimised focusing conditions corresponding to the theory of Guha et al were approached in the type I phase matching geometry, and despite the existence of a 1° walkoff angle, the minimum oscillation threshold was measured to be around 0.3 mJ. Generally, pump depletions of about 35 % were obtained, at around four times threshold. These devices could be angle tuned (through crystal internal angle 14°) from 457 to 666 nm (signal wave) and 1.6 mum to 768 nm (idler wave). (The whole of the range 420 nm to 2.3 mum could be covered with such a device given additional mirror sets). The all-solid-state type II geometry lithium triborate optical parametric oscillator was also pumped at 266 nm, when it was temperature tunable (20 - 200 °C) from 306 to 314 nm (signal wave) and 2.03 to 1.75 mum (idler wave). Pump depletions of 25 % were demonstrated with this device at pump energies of four times threshold. In addition to the above experimental investigations, the thesis addresses the issues of (i) choice of nonlinear material for optical parametric oscillators in terms of appropriate figures of merit, and (ii) optimisation of pump and resonated wave focusing parameters. Reviews of the appropriate theoretical background to phase matching geometries and optical parametric interaction are included.