To see the other types of publications on this topic, follow the link: Spectrophotometry.

Dissertations / Theses on the topic 'Spectrophotometry'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Spectrophotometry.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Morris, David Edward. "Quantitative spectrophotometry on scattering media." Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594829.

Full text
Abstract:
Performing spectrophotometry upon a scattering medium is not trivial as the relationship between the absorption of the medium and its attenuation of light is non-linear. Within this thesis the form of this relationship is investigated, with a view to enabling improvements over current spectrophotometric methods. First, an expression is derived that describes the relationship, both in terms of the absorption coefficient of the medium and the modulation frequency of light used to probe the sample. The expression takes the form of a power series in terms of the absorption coefficient and the modulation frequency, with the coefficients being scaled cumulants of the distribution of photon flight times, which is the temporal point spread function. Approximate expressions for the cumulants of the temporal point spread function are then calculated for various medium geometries based upon expresions for the tempora1 point spread function derived using photon diffusion theory. These expressions allow for trends in the relationship between the scattering coefficient of the medium and the cumulants to be assessed. A number of method .. for performing quantitative spectrophotometry are then described that are based upon the expressions derived. The effectiveness of the proposed methods is assessed by applying the methods to results from Monte Carlo simulations of a tissue phantom. The above methods assume that the absorbers present in a medium are evenly distributed. A method by which spectrophotometry can be performed when this is not the case is then described , assuming the properties of only a single region of this heterogeneous medium is of interest. Finally, a, review of previous spectrophotometric methods is given, relating the methods and assumptions which are made to the theory described in the thesis. A comparison between the methods described in the thesis and those reviewed show that the novel methods described can give an improvement in accuracy when used to determine the concentrations of known absorbers present with in a scattering medium.
APA, Harvard, Vancouver, ISO, and other styles
2

Lame, Nancy Joanne. "Imaging spectrophotometry of planetary nebulae /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487864485228655.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Ives, Charlotte. "Prediction of surgical site infections using spectrophotometry." Thesis, University of Newcastle Upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427284.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Halliwell, D. R. "Applications of acousto-optic filters in astronomical spectrophotometry." Thesis, Queen's University Belfast, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374195.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Wallace, Vincent Patrick. "Spectrophotometry for the assessment of pigmented skin lesions." Thesis, Institute of Cancer Research (University Of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266622.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Sooväli, Lilli. "Spectrophotometric measurements and their uncertainty in chemical analysis and dissociation constant measurements /." Online version, 2006. http://dspace.utlib.ee/dspace/bitstream/10062/627/5/soovalililli.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Yang, Xiaotian. "Interfacing spectrophotometry to process liquors applications to kraft pulping." Doctoral thesis, KTH, Chemistry, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3428.

Full text
Abstract:

This thesis summarizes the outcome of work performed withthe objective to contribute to the knowledge and development ofthe kraft cooking process using spectrophotometricinterfaces.

In kraft cooking, it is desirable to maximize the removal oflignin in the cook without loss of pulp strength. Theselectivity can be improved by exchanging some of the hydrogensulfide ion in the white liquor for polysulfides. Paper Ipresents a spectrophotometric method for in-line monitoring ofthe electrochemical production of polysulfide using anATR-probe for the UV-Vis range. A linear relation existsbetween the ATR-probe response and the concentration ofabsorbing species. Thus the process can be followed by simplemonitoring of a few wavelengths.

A spectrophotometric monitoring system using a durableNafion ionomer membrane interface for continuous on-linemeasurement of sulfide and dissolved lignin during kraftcooking has previously been developed by our group. In paperII, the permeation of low molecular weight anions from liquorshaving high ionic strengths through a membrane in Na+ form hasbeen studied. A general relation between penetration and ionsize approximated by molecular weight has been established. Thepenetration of different anions can be explained as a diffusionthrough the winding membrane channels. Further the differentanions transport independently without being interfered by thesample matrix.

In light of this validation, we applied the membraneinterface to the determination of anthraquinone-2-sulfonate(AQ-S) in alkaline pulping liquor. In paper III, a simple andrapid spectrophotometric method was developed and implementedon real samples. Interferences from other compounds penetratingthe membrane were minimized by reduction of the penetrated AQ-Sand measurement at 520 nm. This method is quick and can be usedon-line. Further, we extended the method to determination ofanthraquinone (AQ) in pulping liquor (paper IV). Although AQ isregarded as insoluble, it was found that the apparentsolubility of AQ in alkaline solutions increases considerablyin the presence of lignin, reaching 0.14 g/L at 90 oC. Thismakes the calibration of AQ possible. Time-resolvedmeasurements of dissolved AQ in 3 kraft-AQ pulping processeswere performed.

The results show that the membrane has great potential aspart of a selective interface in applications where theconcentrations of small anions are to be monitored in mediawith high ionic strength.

Keywords: Kraft cooking, On-line, Sulfide, Lignin,Polysulfide excess sulfur, Anthraquinone-2-Sulfonate (AQ-S),Anthraquinone (AQ), Nafion Membrane, UV-Vis, ATR-probe,Spectrophotometric.

APA, Harvard, Vancouver, ISO, and other styles
8

Gómez, Leal Illeana. "Spectrophotometry of the infrared emission of Earth-like Planets." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00962379.

Full text
Abstract:
Le signal thermique d'une exoplanète tellurique est une clé pour caractériser les propriétés physiques et chimiques de son atmosphère. La résolution spectrale, et donc la caractérisation spectrale que nous pouvons réaliser des planètes extrasolaires, est malheureusement très limité, en particulier pour les planètes similaires à la Terre. Dans cette thèse, j'ai étudié la possibilité de caractériser des exoplanètes telluriques par l'analyse de la variabilité de son émission infrarouge. L'émission thermique apparente est en effet modulée par les saisons, la rotation de la planète, le mouvement et la variabilité des nuages, la phase orbitale, et aussi par la présence des satellites naturels.Premièrement, nous avons étudié l' émission thermique de la Terre vue en tant que point-source distante, ainsi que la variabilité et la dépendance du signal de la géométrie d'observation. J'ai modélisé l'émission de la Terre à l'aide des données satellitaires et des données produites par des modèles de circulation général (GCMs) du Laboratoire de Météorologie Dynamique de Paris (LMD), en comparant les deux types de données afin de valider les simulations.Pendant la deuxième partie de mon travail, j'ai utilisé des donnés du GCM pour modéliser des planètes telluriques qui diffèrent de la Terre par seulement un ou deux paramètres tels que: la vitesse de rotation (y compris des planètes synchrones), une surface planétaire entièrement recouverte par la glace ou de l'eau, l'obliquité de l'axe de rotation ou l'excentricité de l'orbite. Pour toutes ces planètes virtuelles, j'ai étudié le climat, déduit les propriétés physiques de la planète, et produit et analysé les signaux intégrés associés à différentes géométries d'observation.La dernière partie de la thèse est un travail préliminaire qui consiste en ne plus considérer l'émission bolométrique mais le signal de bandes spectrales étroites, grâce à une nouvelle génération de GCM. Parce que chaque bande explore un niveau spécifique dans l'atmosphère, l'étude de la variation du spectre en comparant les variabilités photométriques entre les bandes, permet d'étudier la dynamique, la composition, la distribution et l'évolution de l'atmosphère de la planète, ce qui ouvre un champ encore inexploré pour la caractérisation des exoplanètes.
APA, Harvard, Vancouver, ISO, and other styles
9

Hammersley, Peter Laurence. "Near infrared spectrophotometry and the 2.2 micron galactic survey." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46330.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Geswindt, Theodore Earl. "The reactions of osmium (VIII) in hydroxide medium." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/960.

Full text
Abstract:
Spectrophotometric techniques were used to elucidate the discrepancies surrounding the reduction of osmium tetroxide by several primary alcohols in a hydroxide matrix. In contrast to the documented literature, this reaction was observed to occur in two consecutive reaction steps. Geometrical and computational analysis of kinetic data revealed that the reaction proceeds by the following reaction model: Os(VIII) + RCH2OH Os(VI) + RCHO Os(VIII) + Os(VI) Os2(VII) k1 k+2 k-2 The conditional rate constants and molar extinction coefficients were calculated using custom written software. A hydride transfer mechanism, coupled with the synchronous removal of the hydroxyl proton of the alcohol, was postulated. The complexation between osmium(VIII) and osmium(VI) was investigated. Mole ratio titrations and mole fraction plots show that at pH 14.3 a 1:1 complexation occurs between osmium(VIII) and osmium(VI). The equilibrium constants and molar extinction coefficients calculated by these methods were found to be consistent with the parameters obtained from the reduction of osmium tetroxide by primary alcohols at pH 14.3. The formation of a mixed oxidation state dimeric osmium complex (denoted Os2(VII)) has been proposed. Key words: Spectrophotometric techniques, osmium tetroxide, osmium(VIII), primary alcohols, osmium(VI).
APA, Harvard, Vancouver, ISO, and other styles
11

Silva, Junior Ranulfo Combuca da [UNESP]. "Desenvolvimento de um método de análise por injeção em fluxo (FIA) para determinação de dissulfeto de tetrametiltiuram (tiram) utilizando reagente imobilizado em reator de fase sólida (RFS)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/97765.

Full text
Abstract:
Made available in DSpace on 2014-06-11T19:29:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-24Bitstream added on 2014-06-13T19:38:00Z : No. of bitstreams: 1 silvajunior_rc_me_sjrp.pdf: 403500 bytes, checksum: 3cd17a24d35b6720b9e58848e90ec823 (MD5)
No presente trabalho, foi desenvolvido um método analítico destinado à quantificação do fungicida Tiram baseado na capacidade que este possui de complexar íons Cu2+. A quantificação foi efetuada por meio do acoplamento de espectrofotometria visível a um reator de fase sólida (RFS) utilizando de técnicas de análise em fluxo. O RFS utilizado foi constituído por um tubo de plástico (12 cm e 2 mm d.i.) preenchido por resina poliéster finamente triturada contendo fosfato de Cu2+ imobilizado. Durante o contato de 100 µL de Tiram com íons Cu2+ imobilizados na resina, forma-se o complexo Cu2+ / Tiram. Nesta etapa, o complexo é liberado para a solução carregadora (água) a uma vazão de 2,5 mL min-1. Sendo intensamente colorido esta espécie é a base do presente método de quantificação a 439 nm. Com o desenvolvimento da reação, a curva analítica obtida foi linear no intervalo de concentração de 3,0 x 10-5 a 3,4 x 10-4 mol L-1, com limite de detecção de 6,95 x 10-5 mol L-1 e freqüência de amostragem de 60 determinações por hora
In this dissertation an analytical method for the Thiram fungicide quantification, based on the capacity which it has a complex copper ions was developed. The quantification was performed by mean of visible spectrophotometry coupling a solid-phase reactor using flow techniques. The solid-phase reactor used is consisting of a plastic tube (12 cm and 2 mm diameter) filled with finely crushed polyester resin containing copper phosphate immobilized. During the contact of 100 µL Thiram with Cu2 + ions immobilized on the resin is formed the complex Cu2 + / Thiram. At this stage, the complex is released into the carrier solution (water) with flow rate of 2,5 mL min-1 being intensely colored and this species is the basis of this method of quantification at 439 nm. With the development of the reaction, analytical curve was linear on the concentration range of 3,0 x 10-5 to 3,0 x 10-4 mol L-1 with a detection limit of 6,95 x 10-5 mol L-1 and a sampling frequency of 60 determinations per hour
APA, Harvard, Vancouver, ISO, and other styles
12

Wolf, Katharine. "Flow injection analysis with photodiode array detection." Thesis, University of Hull, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278427.

Full text
APA, Harvard, Vancouver, ISO, and other styles
13

Rakbamrung, Nawasit. "Determination of some inorganic ions, with or without preconcentration, by flow injection analysis or ion chromatography." Thesis, Liverpool John Moores University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288214.

Full text
APA, Harvard, Vancouver, ISO, and other styles
14

Garazdiuk, M. S., V. T. Bachynskiy, O. Ya Vanchuliak, and I. Bezhenar. "Spectrophotometry in the ultraviolet range as a method of time since death estimation." Thesis, Матеріали 99 підсумкової науково-практичної конференції професорсько-викладацького персоналу ВДНЗ України «Буковинський державний медичний університет». – Чернівці, 2018. – С. 5, 2018. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/13659.

Full text
Abstract:
Time since death estimation is an impotant and not completely resolved issues of forensic practice. The analysis of cerebrospinal fluid as a stable and separated from the action of environmental medium factors can be used for solving of this problem.
APA, Harvard, Vancouver, ISO, and other styles
15

Moncrieff, Kathleen Elizabeth. "Development of a new calcium II H and K spectrophotometric temperature index /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2082.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
16

Wheatley, Robert Alan. "Aldehydic lipid peroxidation products : flow analysis using spectrophotometry and chemiluminescence." Thesis, University of Hull, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363331.

Full text
APA, Harvard, Vancouver, ISO, and other styles
17

Silva, Junior Ranulfo Combuca da. "Desenvolvimento de um método de análise por injeção em fluxo (FIA) para determinação de dissulfeto de tetrametiltiuram (tiram) utilizando reagente imobilizado em reator de fase sólida (RFS) /." São José do Rio Preto : [s.n.], 2011. http://hdl.handle.net/11449/97765.

Full text
Abstract:
Resumo: No presente trabalho, foi desenvolvido um método analítico destinado à quantificação do fungicida Tiram baseado na capacidade que este possui de complexar íons Cu2+. A quantificação foi efetuada por meio do acoplamento de espectrofotometria visível a um reator de fase sólida (RFS) utilizando de técnicas de análise em fluxo. O RFS utilizado foi constituído por um tubo de plástico (12 cm e 2 mm d.i.) preenchido por resina poliéster finamente triturada contendo fosfato de Cu2+ imobilizado. Durante o contato de 100 µL de Tiram com íons Cu2+ imobilizados na resina, forma-se o complexo Cu2+ / Tiram. Nesta etapa, o complexo é liberado para a solução carregadora (água) a uma vazão de 2,5 mL min-1. Sendo intensamente colorido esta espécie é a base do presente método de quantificação a 439 nm. Com o desenvolvimento da reação, a curva analítica obtida foi linear no intervalo de concentração de 3,0 x 10-5 a 3,4 x 10-4 mol L-1, com limite de detecção de 6,95 x 10-5 mol L-1 e freqüência de amostragem de 60 determinações por hora
Abstract: In this dissertation an analytical method for the Thiram fungicide quantification, based on the capacity which it has a complex copper ions was developed. The quantification was performed by mean of visible spectrophotometry coupling a solid-phase reactor using flow techniques. The solid-phase reactor used is consisting of a plastic tube (12 cm and 2 mm diameter) filled with finely crushed polyester resin containing copper phosphate immobilized. During the contact of 100 µL Thiram with Cu2 + ions immobilized on the resin is formed the complex Cu2 + / Thiram. At this stage, the complex is released into the carrier solution (water) with flow rate of 2,5 mL min-1 being intensely colored and this species is the basis of this method of quantification at 439 nm. With the development of the reaction, analytical curve was linear on the concentration range of 3,0 x 10-5 to 3,0 x 10-4 mol L-1 with a detection limit of 6,95 x 10-5 mol L-1 and a sampling frequency of 60 determinations per hour
Orientador: Marcos Fernando de Souza Teixeira
Coorientador: Homero Marques Gomes
Banca: Mario Sergio Galhiane
Banca: Ronaldo Spezia Nunes
Mestre
APA, Harvard, Vancouver, ISO, and other styles
18

Procter, Alison Mary. "Near infrared spectrophotometry for the in vitro study of cellular metabolic activity." Thesis, Keele University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245353.

Full text
APA, Harvard, Vancouver, ISO, and other styles
19

Kuzenko, Yevhen Viktorovych, Анатолій Миколайович Романюк, Анатолий Николаевич Романюк, Anatolii Mykolaiovych Romaniuk, H. Logvinova, H. Korobchanskaj, Євген Вікторович Кузенко, and Евгений Викторович Кузенко. "Periodontal DNA changes under the influence of CR6+, study by infrared spectrophotometry." Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/35930.

Full text
Abstract:
The infrared spectroscopy is widely used for gathering structural information on biological systems, but not used in periodontitis researchers. The study of DNA by infrared spectroscopy requires peeled DNA samples. The infrared spectrs of DNA show many characteristic: denaturation, alkylation, dehydration and conformational transition. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35930
APA, Harvard, Vancouver, ISO, and other styles
20

Lehan, John Philip. "Microstructural investigations of optical coatings by backscattering spectrometry, electron diffraction, and spectrophotometry." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/184997.

Full text
Abstract:
Backscattering spectrometry with MeV ⁴He ion beams is investigated as a tool for determining composition with applications to optical coatings. Equations for the compositional analysis of thin films are reviewed. The effect of nuclear charge screening on compositional analysis by MeV ⁴He beams is discussed and examples involving the lanthanide trifluorides illustrate the importance of this correction to avoid possibly erroneous conclusions about sample composition. High probe beam energy is also briefly discussed as a method of reducing the overlap of peaks in backscattering spectra which reduces the technique's accuracy. Complications such as non-Rutherford scattering cross sections for light elements are addressed and an example given. The application of backscattering spectrometry to the depth profiling of elemental constituents in thin films is discussed. It is found that the backscattering spectrum itself provides a reasonable depth profile; however, its depth resolution is limited by the energy resolution of the detection system and energy straggling of the probe beam in the solid. In addition, the depth profile suffers from considerable noise. A method is derived using the principle of maximum likelihood which allows hypothetical depth profiles to be tested and the effects of energy straggling and detection system resolution to be separated from the depth profile. Several examples involving two hypothetical depth profile models are presented. Finally, backscattering spectrometry is combined with scanning electron microscopy, transmission electron microscopy, electron diffraction, x-ray photoelectron spectroscopy, and spectrophotometry in a microstructural survey of hafnium dioxide optical coatings deposited by electron beam evaporation and ion-assisted deposition (IAD). It is found that hafnium dioxide films deposited at temperatures below 300°C are amorphous and exhibit a negative optical inhomogeneity. The refractive index as well as the inhomogeneity are strongly influenced by the oxygen present during film deposition. The inhomogeneity can be removed by IAD which also increases the refractive index of the film. In addition, low energy IAD is found to increase the refractive of the films without affecting the inhomogeneity. This is explained by the preferential sputtering of hydroxide from the growing film surface by the bombarding ions.
APA, Harvard, Vancouver, ISO, and other styles
21

Johnston, Andrew. "An investigation of free radical involvement in cell death in a cell culture model of ischaemia." Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343128.

Full text
APA, Harvard, Vancouver, ISO, and other styles
22

Rodrigues, Junior Alvino. "Metodo espectrofotometrico para determinação de vancomicina." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248826.

Full text
Abstract:
Orientador: Matthieu Tubino
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-13T14:10:39Z (GMT). No. of bitstreams: 1 RodriguesJunior_Alvino_M.pdf: 694987 bytes, checksum: 1b71ae2953ae2ae4410308e036a7f084 (MD5) Previous issue date: 2008
Resumo: Este trabalho teve por objetivo o desenvolvimento de um método analítico quantitativo de para análise de vancomicina (em sua forma denominada vancomicina base - VCM, e na forma de cloridrato de vancomicina - HVCM), com utilização de espectrofotometria na região do visível. O método tem como princípio a reação da vancomicina com íons cobre(II), resultando na formação de um complexo de coloração lilás, que apresenta absorção máxima em 555 nm. Realizaram-se estudos para a otimização da reação entre a vancomicina e o íon cobre(II). Dentre estes fatores, destacam-se: a escolha do sal de cobre(II) utilizado na reação com vancomicina; a utilização de etanol, no preparo das soluções e como componente do meio reacional; pH do meio reacional; proporção molar entre vancomicina e íon cobre(II). A otimização destes parâmetros resultou em um método com faixa de trabalho de 1,0 × 10 mol L a 1,0 × 10 mol L, com coeficiente de correlação de 0,9997 e limite de detecção (LOD) e limite de quantificação (LOQ) de 4,0 × 10 mol L e 1,0 × 10 mol L, respectivamente. O método proposto também foi estudado em relação à recuperação de vancomicina frente a excipientes comumente utilizados na indústria farmacêutica. Os resultados obtidos foram comparados com método de referência cromatográfico, onde foi observado que o método proposto apresentou maior repepetibilidade para as amostras de HVCM e maior recuperação para as amostras de VCM. O procedimento para a realização de análises pelo método proposto é de fácil execução e de baixo custo
Abstract: The aim of this work was to develop a quantitative spectrophotometric analytical method, in the visible region of the spectrum, for the determination of vancomycin (in the form known as base ¿ VCM, and in the form of chloridrate, HVCM). The developed method uses the reaction between vancomycin and ions copper(II) that forms a lilac complex which spectrum shown a maximum at 555 nm. Studies were done in order to optimize the method. Among them can be cited: selection of the copper(II) salt to be used in the reaction with vancomycin; use of ethanol as component of the reaction for the preparation of the solution and as component of the reaction medium; pH of the reaction medium; molar proportion between vancomycin and copper(II) ions. The parameters optimization resulted in a method with a linear range from 1,0 × 10 mol L to 1,0 × 10 mol L, with correlation coefficient value of 0,9997, limit of detection (LOD) and limit of quantification (LOQ) values of 4,0 × 10 mol L and 1,0 × 10 mol L, respectively. The proposed medium was also studied with respect to the vancomycin recovering when mixed with excipients commonly used in the pharmaceutical industry. The obtained results were compared with those of the reference chromatographic method (HPLC), where it was observed the proposed method showed a better reprodutibility for HVCM samples and higher recoveries for VCM samples. The analytical procedure that is proposed in this work is simple to be performed and the cost is very low
Mestrado
Quimica Analitica
Mestre em Química
APA, Harvard, Vancouver, ISO, and other styles
23

Avramidis, Stefanos. "Simulation and parameter estimation of spectrophotometric instruments ." Thesis, KTH, Numerical Analysis and Computer Science, NADA, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12292.

Full text
Abstract:

The paper and the graphics industries use two instruments with different optical geometry (d/0 and 45/0) to measure the quality of paper prints. The instruments have been reported to yield incompatible measurements and even rank samples differently in some cases, causing communication problems between these sectors of industry.A preliminary investigation concluded that the inter-instrument difference could be significantly influenced by external factors (background, calibration, heterogeneity of the medium). A simple methodology for eliminating these external factors and thereby minimizing the instrument differences has been derived. The measurements showed that, when the external factors are eliminated, and there is no fluorescence or gloss influence, the inter-instrument difference becomes small, depends on the instrument geometry, and varies systematically with the scattering, absorption, and transmittance properties of the sample.A detailed description of the impact of the geometry on the results has been presented regarding a large sample range. Simulations with the radiative transfer model DORT2002 showed that the instruments measurements follow the physical radiative transfer model except in cases of samples with extreme properties. The conclusion is that the physical explanation of the geometrical inter-instrument differences is based on the different degree of light permeation from the two geometries, which eventually results in a different degree of influence from near-surface bulk scattering. It was also shown that the d/0 instrument fulfils the assumptions of a diffuse field of reflected light from the medium only for samples that resemble the perfect diffuser but it yields an anisotropic field of reflected light when there is significant absorption or transmittance. In the latter case, the 45/0 proves to be less anisotropic than the d/0.In the process, the computational performance of the DORT2002 has been significantly improved. After the modification of the DORT2002 in order to include the 45/0 geometry, the Gauss-Newton optimization algorithm for the solution of the inverse problem was qualified as the most appropriate one, after testing different optimization methods for performance, stability and accuracy. Finally, a new homotopic initial-value algorithm for routine tasks (spectral calculations) was introduced, which resulted in a further three-fold speedup of the whole algorithm.The paper and the graphics industries use two instruments with different optical geometry (d/0 and 45/0) to measure the quality of paper prints. The instruments have been reported to yield incompatible measurements and even rank samples differently in some cases, causing communication problems between these sectors of industry.A preliminary investigation concluded that the inter-instrument difference could be significantly influenced by external factors (background, calibration, heterogeneity of the medium). A simple methodology for eliminating these external factors and thereby minimizing the instrument differences has been derived. The measurements showed that, when the external factors are eliminated, and there is no fluorescence or gloss influence, the inter-instrument difference becomes small, depends on the instrument geometry, and varies systematically with the scattering, absorption, and transmittance properties of the sample.A detailed description of the impact of the geometry on the results has been presented regarding a large sample range. Simulations with the radiative transfer model DORT2002 showed that the instruments measurements follow the physical radiative transfer model except in cases of samples with extreme properties. The conclusion is that the physical explanation of the geometrical inter-instrument differences is based on the different degree of light permeation from the two geometries, which eventually results in a different degree of influence from near-surface bulk scattering. It was also shown that the d/0 instrument fulfils the assumptions of a diffuse field of reflected light from the medium only for samples that resemble the perfect diffuser but it yields an anisotropic field of reflected light when there is significant absorption or transmittance. In the latter case, the 45/0 proves to be less anisotropic than the d/0.In the process, the computational performance of the DORT2002 has been significantly improved. After the modification of the DORT2002 in order to include the 45/0 geometry, the Gauss-Newton optimization algorithm for the solution of the inverse problem was qualified as the most appropriate one, after testing different optimization methods for performance, stability and accuracy. Finally, a new homotopic initial-value algorithm for routine tasks (spectral calculations) was introduced, which resulted in a further three-fold speedup of the whole algorithm.


QC 20100707
PaperOpt, Paper Optics and Colour
APA, Harvard, Vancouver, ISO, and other styles
24

Jarad, F. D. "Application of spectrophotometry and computerised digital imaging to colour perception in restorative dentistry." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368601.

Full text
APA, Harvard, Vancouver, ISO, and other styles
25

Phiri, Mohau Justice. "On-line monitoring of base metals solutions in flotation using diffuse reflectance spectrophotometry." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5173.

Full text
Abstract:
Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010.
Thesis submitted in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE IN ENGINEERING (MINERAL PROCESSING) in the Department of Processing Engineering at the University of Stellenbosch
ENGLISH ABSTRACT: This work evaluates the use of inverse least squares (ILS) and classical least squares (CLS) models for calibration of a diffuse reflectance spectrophotometer for on-line monitoring of the aqueous phase in a flotation cells. Both models use a Beer's law for the quantification of the metals. The formulated statistical models are compared to a proprietary Blue Cube model in terms of prediction ability to determine the potential applicability of the models. A diffuse reflectance spectrophotometry was used for simultaneous analysis of copper (Cu), cobalt (Co) and zinc (Zn) in the solutions. The laboratory set-up of Blue Cube instrument was used for the experimental analysis. The concentrations and matrix compositions of the samples are simulated according to Skorpion zinc mine plant conditions. The calibration samples were prepared using a simplex-centroid mixture design with the triplicates of the centroid run. The unknown or test samples were prepared randomly within the same concentration of the calibration samples. The effects of temperature and nickel concentration on absorption of the metals were evaluated in the following range, 20 - 80 °C and 125 - 400 ppm, respectively. The statistical models (ILS and CLS) were calibrated from visible and near infrared (VNIR) spectra data of the calibration samples. A modified Beer's method was used as a preprocessing technique to convert the raw data into absorbance values. The manual wavelength selection procedure was used to select the wavelengths to be used in both models. The quality of the models was evaluated based on Rª and % root mean squared error (RMSE) values with 0.90 and 10% used as the guideline for the respective statistical parameters. Both ILS and CLS models showed good results for all three metals (Cu, Co and Zn) during their calibration steps. It was further shown that both models give worse predictions for Zn as compared to other metals due to its low relative intensity in the mixture. The derivative orders of absorbance spectra that were used to enhance the prediction results of Zn had no positive effect but they rather lowered accuracy of predictions. An increase in temperature was found to increase the intensities of the absorption spectra of all the metals while an increase in nickel concentration decreases the prediction ability of model. The developed statistical models were compared to a Blue Cube model in terms of prediction ability using analysis of variance (ANOVA) test. The ANOVA results revealed that there is no statistical difference between the developed models and Blue Cube model since the F-values for all the metals were below the critical F-value. Furthermore, the partial least squares (PLS) model shows an increased accuracy results for prediction of zinc metal as compared to both the ILS and CLS models. Finally, good comparisons of the statistical models results with atomic absorption spectroscopy (AAS) analyses were establish for the unknown samples. The study demonstrates that chemometric models (ILS and CLS) developed here can be used for quantification of several metals in real hydrometallurgical solutions as samples were simulated according to a plant conditions. However, in order to have confidence in the results of the models, a factorial-mixture design must be used to study the effect of temperature and nickel concentration. Moreover the models must be further tested and validated on the real samples from a plant.
AFRIKAANSE OPSOMMING: Hierdie werkstuk evalueer die gebruik van inverse kleinste kwadraatmetodes (IKK) en klassieke kleinste kwadraatmetodes (KKK) vir die kalibrasie van 'n diffuse reflektansiespektrofotometer vir die aanlyn monitering van die waterige fase in flottasieselle. Beer se wet word vir die kwantifisering van metale vir albei modelle gebruik. Die omskrewe data-gebaseerde modelle is op grond van voorspellingsvermoë vergelyk met'n. Blue Cube model, sodat die moontlike toepaslikheid van hierdie modelle bepaal kan word. 'n Diffuse reflectantie spektrofotometrie is ingespan vir die gelyktydige analise van koper (Cu), kobalt (Co) en sink (Zn) in oplossing. Eksperimentele analises is met behulp van 'n laboratoriumopstelling met 'n Blue Cube instrument uitgevoer. Die konsentrasies en matriks-samestellings van monsters is gesimuleer om Skorpion sinkmyn aanlegkondisies na te boots. Kalibrasie monsters is voorberei volgens . simpleks-sentroïed mengselontwerp met drievoudige sentroïede lopies. Onbekende (toets) monsters is ewekansig voorberei binne dieselfde konsentrasie spesifikasies as die kalibrasie monsters. Die invloed van temperatuur en nikkelkonsenstrasie op die absorpsie van die metale is in die bestek van 20 - 80 °C en 125 - 400 dpm, onderskeidelik, bepaal. Die data-gebaseerde modelle (IKK en KKK) is met sigbare en naby infrarooi (SNIR) spektra data van die kalibrasie monsters gekalibreer. 'n Gewysigde Beer metode is vir data voorbereiding benut om rou data na absorbansie waardes om te skakel. Die handgolflengte-seleksieprosedure is vir beide modelle gebruik om die golflengtes te kies. Die kwaliteit van die modelle is op grond van Rª en % wortel gemiddelde kwadratiese fout (WGKF) geevalueer, met waardes van 0.90 en 10% (onderskeidelik) as riglyne vir hierdie statistiese parameters. Beide IKK en KKK modelle het vir hul kalibrasie stappe vir al drie metale (Cu, Co en Zn) goeie resultate getoon. Dit is verder getoon dat albei modelle die slegste voorspellings lewer vir Zn (vergeleke met die ander metale) as gevolg van Zn se lae relatiewe intensiteit in die mengsel. Afgeleide ordes van absorbansie spektra is gebruik om die Zn voorspellings te versterk, maar het geen positiewe effek gehad nie; inteendeel, voorspellingakkuraatheid is verlaag. ʼn Verhoging in temperatuur het die intensiteite van die absorpsie spektra van alle metale verhoog, terwyl ʼn verhoging in nikkelkonsentrasie die voorspellingakkuraatheid van die modelle verlaag het. Die ontwikkelde data-gebaseerde modelle is met ʼn Blue Cube model vergelyk in terme van voorspellingsvermoë met behulp van variansie-analise (ANOVA). Die ANOVA resultate toon dat daar geen statistiese verskil tussen die ontwikkelde modelle en die Blue Cube model is nie, aangesien die F-waardes vir al die metale onder die kritiese F-waarde is. Die gedeeltelike kleinste kwadraatmodel (GKK) toon verder verhoogde voorspellingakkuraat-heid vir sinkmetaal tenoor beide die IKK en KKK modelle. Ten slotte, goeie ooreenstemming van die data-gebaseerde modelresultate met atoomabsorpsie spektroskopie (AAS) analise is vir die onbekende monsters gevind. Hierdie werkstuk toon dat die chemometriese modelle (IKK en KKK) wat hier ontwikkel is, gebruik kan word vir die kwantifisering van verskeie metale in werklike hidrometallurgiese oplossings, aangesien monsters gesimuleer is volgens aanlegkondisies. Om egter verdere vertroue te hê in die modelresultate, sal ʼn faktoriaal-mengselontwerp toegepas moet word om die effek van temperatuur en nikkelkonsentrasie te ondersoek. Voorts moet die modelle verder getoets en gevalideer word op werklike monsters van ʼn aanleg.
APA, Harvard, Vancouver, ISO, and other styles
26

Hajizadeh-Saffar, Mohsen. "The non-invasive quantification of cutaneous haemoglobin and its oxygenation by reflectance spectrophotometry." Thesis, University of Leeds, 1988. http://etheses.whiterose.ac.uk/242/.

Full text
Abstract:
The work detailed in this study describes the design of a rapid scanning multiwavelength reflectance spectrophotometer and its application to the measurement of cutaneous pigments. In this instrument the radiation from a 6V, 20 W quartz halogen lamp is transmitted to the reflectance probe by fibre optics and illuminates the skin surface perpendicularly. The diffuse reflected light is then collected and transmitted to a rotating circular variable filter, CVF. The CVF is driven by a BBC Microcomputer and the spectrum from 356 to 721 nm is measured at 200 equally spaced wavelengths in 2.8 s. Based upon the spectral differences between the absorbances of oxy and reduced haemoglobin, two indices were defined for quantifying the amount of haemoglobin, the "haemoglobin index", and oxygen saturation, the "oxygenation index", in a blood containing sample. The haemoglobin index is derived from the spectrum of haemoglobin as the difference between two gradients calculated between three isobestic points (527.5,544, and 573 nm). To measure the oxygenation index, two isobestic points (544 and 573 nm) and a point at 558.5 nm, where the specific absorption coefficient of oxy and reduced haemoglobin differ, are used. Linear calibration curves of the haemoglobin index against haemoglobin content in-vitro using collimated and diffused light were obtained. The oxygenation index was converted to percentage oxygen saturation by comparing the oxygenation index of a sample with that of reduced and fully oxygenated blood. The validity of the method was examined by measuring the oxygen dissociation curve of human blood at pCO2 of 40 mmHg, pH of 7.33, and 37 °C and comparing the results with between measured and published curves confirms that the oxygen saturation of blood can be accurately measured by the present method. The scattering properties of the epidermis were studied by measuring the angular distribution of light scattered by a sheet of epidermis. It was found that most of the radiation transmitted through the epidermis is forwardly orientated; 67% of the incident radiation at 630 nm remains within 22.5 degrees of the incident beam. To facilitate the study of the absorption properties of epidermis a new index called the "melanin index" was introduced and quantified using a synthetic melanin compound for calibration purposes. The melanin index is based on the slope of the LIR spectrum of skin surface between 650 -700 nm, and was used to investigate the melanin pigmentation levels of different ethnic groups. Reflectance spectrometry was used to study the amount of haemoglobin and oxygen saturation of the superficial blood in skin. Variations in the haemoglobin index of an arm and a finger tip were studied under different conditions of temperature and height of the limb relative to the heart. The effects of applying a topical vasodilating chemical and of the thermal regulatory function of blood at three different sites on a hand 'were also studied. In all these measurements the results were in good agreement with the biological prediction and confirmed the satisfactory operation of the instrument, the validity of the indices and their usefulness in quantifying "skin colour" changes. To find the correlation between in-vivo haemoglobin index and the true amount of haemoglobin in blood in g/dl, skin reflectance measurements and blood samples were taken from patients who attended a blood clinic. The correlation coefficient between haemoglobin content (g/dl) and the haemoglobin index of the patients were 0.4 and 0.2 respectively. The weak correlation coefficient is attributable to the difficulty of defining the volume of blood observed when measuring the haemoglobin index. The instrument was used to measure changes in the blood content of the skin of animal and human subjects following treatment by photochemotherapy.
APA, Harvard, Vancouver, ISO, and other styles
27

Villarroel, Cortés Milko Javier [UNESP]. "Avaliação espectrofotométrica de diferentes sistemas cerâmicos." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/101384.

Full text
Abstract:
Made available in DSpace on 2014-06-11T19:31:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-24Bitstream added on 2014-06-13T20:22:09Z : No. of bitstreams: 1 villarroelcortes_mj_dr_arafo.pdf: 442355 bytes, checksum: 72b2cbdf6d7482f035c59c5db829812e (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste trabalho foi avaliar espectrofotometricamente a transmitancia direta e refletância de diferentes sistemas cerâmicos. Foram selecionados 12 sistemas cerâmicos: Grupo I Cercon B (Dentsply); Grupo II Cercon A (Dentsply); Grupo III In-Ceram Alumina (Vita); Grupo IV In-Ceram Spinell (Vita); Grupo V Procera Zirconia 2 (Nobel Biocare); Grupo VI Procera Zirconia 3 (Nobel Biocare); Grupo VII Procera Zirconia 4 (Nobel Biocare); Grupo VIII Procera Zirconia 5 (Nobel Biocare); Grupo IX IPS e.max Press MO (Ivoclar- Vivadent); Grupo X IPS e.max Press HO (Ivoclar-Vivadent); Grupo XI Zirconforce (Cubo) e Grupo XII IPS d.sing (Ivoclar-Vivadent). Utilizou-se um espectrofotômetro para corpos sólidos calibrado para registrar a transmitância da luz com comprimento de onda de 400 a 700nm. Foram confeccionados 5 corpos de prova de infra-estrutura cerâmica (15mm de diâmetro e 0,5mm de espessura) para cada grupo de acordo com a especificações do fabricante. Os valores de transmitância direta foram analisados mediante o teste ANOVA (p<0,05). Pode-se observar que existem diferenças significativas entre os grupos G3, G9 e G12 que apresentaram um comportamento significantemente distinto entre si e entre todos os outros grupos. Não houve diferenças entre os grupos G4, G5, G6, G7, G8, G10 e G11 e entre G1 e G2 para os valores máximos de transmitância. Posteriormente, em uma segunda etapa, os corpos de prova de infra-estrutura foram completados com cerâmicas de cobertura indicada pelo fabricante de cada grupo, obtendo as seguintes dimensões: 15mm de diâmetro e 2mm de espessura. As amostras foram submetidas ao teste de transmitância direta e os resultados foram submetidos ao teste ANOVA (p<0,05). A análise estatística demonstrou diferenças estatísticas entre os grupos em estudo em que G9 e G12 tiveram um comportamento significativamente distinto entre si e com todos os outros grupos...
The aim of this study was to evaluate spectrophotometrically the direct transmittance and reflectance of different ceramic systems. Twelve ceramic systems were selected: Cercon B – Dentsply (Group I), Cercon A – Dentsply (Group II), In-Ceram Alumina – Vita (Group III), In-Ceram Spinell – Vita (Group IV), Zirconia 2 Procera - Nobel Biocare (Group V), Procera Zirconia 3 - Nobel Biocare (Group VI), Zirconia 4 Procera - Nobel Biocare (Group VII), Procera Zirconia 5 - Nobel Biocare (Group VIII), IPS e.max Press MO - Ivoclar-Vivadent (Group IX) and IPS e.max Press HO - Ivoclar-Vivadent (Group X ), Zirconforce – Cubo (Group XI) and IPS d.sing - Ivoclar-Vivadent (Group XII). Spectrophotometer for solids was used calibrated to register in the range of 400 to 700nm. Five ceramic copyings for testing were made (15mm in diameter and 0.5 mm in thickness) for each group according to manufacturer directions. Direct transmittance values were analyzed by ANOVA test (p <0.05). It was observed significant differences between groups G3, G9 and G12 were significantly different behavior between them and all other groups. There were no differences between groups G4, G5, G6, G7, G8, G10, G11 and between G1 and G2 for maximum values of transmittance. In a second stage test bodies were filled with covering ceramic getting the following dimensions: 15mm diameter and 2mm thick. The test bodies were subjected to direct transmittance test and the results were submitted to ANOVA test (p <0.05). Statistical analysis revealed that there were statistical differences between the study groups. G9 and G12 behavior were significantly different between them and all other groups. Same behavior was attributed to groups G5, G6, G7, G8, G10, G11 and between G1 and G2 and between G3 and G4. Finally, complete test bodies were subjected to the reflectance test using the reflectance spectrophotometer CM 2600d (Konica Minolta)... (Complete abstract click electronic access below)
APA, Harvard, Vancouver, ISO, and other styles
28

Azeka, Leandro Augusto Lopes. "Analisador de bilirrubina no soro de neonatos utilizando espectrofotometria direta." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18152/tde-06042009-152204/.

Full text
Abstract:
A icterícia é uma manifestação caracterizada pelo amarelamento da pele e mucosas devido ao excesso de bilirrubina no sangue do paciente. Cerca de 60% dos recém nascidos (RN) manifestam a icterícia nas primeiras semanas de vida, sendo este índice muito maior em neonatos prematuros. Se não corretamente diagnosticada, a alta concentração de bilirrubina pode intoxicar a massa encefálica, provocando uma encefalopatia conhecida como kernicterus. Existem vários métodos para medir a concentração de bilirrubina, e entre eles pode-se citar: métodos bioquímicos laboratoriais que utilizam amostras de sangue coletadas e reagentes específicos, medidores de bilirrubina transcutâneos e espectrofotometria em amostras de soro. O princípio básico desses métodos é a análise colorimétrica, que se baseia na alta absorbância da molécula de bilirrubina no comprimento de onda de 455 nm. O presente trabalho descreve um bilirrubinômetro, que foi desenvolvido para medir a concentração da bilirrubina utilizando a espectrofotometria direta no soro de amostras sanguíneas de neonatos. No projeto do bilirrubinômetro levou-se em consideração o baixo custo de produção, uma boa precisão comparada com outros equipamentos, e a utilização de componentes de alta tecnologia tais como LED com alta intensidade luminosa e fotorreceptores especiais para medir concentrações nas faixas de luz específica. Para a validação do equipamento foram obtidas amostras de sangue de recém nascidos, junto ao Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, e os resultados das medidas realizadas com o bilirrubinômetro construído foram comparados com os obtidos com um bilirrubinômetro comercial e com métodos bioquímicos clássicos. Os resultados da comparação mostraram que o bilirrubinômetro construído apresenta um erro relativo de ± 1,05 mg/dl, que se encontra dentro da média dos bilirrubinômetros diretos e custo de produção relativamente baixo.
Jaundice is a manifestation described as the yellowish staining of the skin and mucous membranes caused by the excessive levels of bilirubin in the patient blood. About 60% of the newborns present this feature in the first weeks of life, and this percentage is much higher in premature neonates. If not correctly detected and treated, the bilirubin can intoxicate the encephalic mass, causing an encephalopathy knowed as kernicterus. There are many methods to measure the bilirubin concentration such as: blood laboratory methods using specific reagents, transcutaneous bilirubin and serum spectrophotometric equipments. The basic principle of these devices is the colorimetric analysis based on the high absorption of the bilirubin molecule in the 455 nm wavelength. This work describes a bilirubin meter that was developed for measure the bilirubin concentration using direct spectrophotometry in the serum of neonates\' blood samples. In the bilirubin meter project it was considered the low production cost, a good precision compared with others similar equipments, and the use of high technology components as high intensity LED and special photoreceptors to measure specific wavelengths. For validation of the equipment it was used newborns blood samples from the Clinics Hospital at the Faculty of Medicine of Ribeirão Preto, and the results obtained with the equipment were compared with the values of a commercial bilirubin meter and with biochemical tests. The results showed that the developed bilirubin meter has a relative error around 1,05 mg/dl, similar to commercial bilirubin meters and a low relative cost.
APA, Harvard, Vancouver, ISO, and other styles
29

Catelani, Tiago Augusto [UNESP]. "Desenvolvimento de sistemas de screening automatizados para determinação de sulfonamidas em mel e procedimento limpo para a quantificação de sulfaquinoxalina em medicamentos veterinários." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/97842.

Full text
Abstract:
Made available in DSpace on 2014-06-11T19:29:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-01-15Bitstream added on 2014-06-13T20:18:56Z : No. of bitstreams: 1 catelani_ta_me_araiq_parcial.pdf: 56034 bytes, checksum: e0fec83762961fb2a290c883707606eb (MD5) Bitstreams deleted on 2014-11-14T12:16:58Z: catelani_ta_me_araiq_parcial.pdf,Bitstream added on 2014-11-14T12:17:45Z : No. of bitstreams: 1 000712502.pdf: 601891 bytes, checksum: 8df643c4b32a26b896742e14086cbcb1 (MD5)
A determinação de antibióticos tem sido assunto cada vez mais presente nos estudos de química, seja sua determinação para o controle de qualidade dos medicamentos ou determinação de resíduos em alimentos. O trabalho foi desenvolvido em duas etapas. A primeira parte do trabalho permitiu o desenvolvimento de uma metodologia simples, rápida e de baixo custo, onde se faz uso do procedimento de Análise por Injeção em Fluxo (FIA) com detecção espectrofotométrica para averiguar a presença de sulfaquinoxalina sódica em amostras de três tipos diferentes de medicamentos veterinários. A metodologia foi otimizada por planejamento de experimentos. O reagente cromogênico utilizado foi o pdimetilaminocinamaldeído (p-DAC) que na presença de ácido clorídrico (HCl) e o surfactante Dodecilsulfato de sódio (SDS), forma um produto colorido (l = 560 nm) com a compostos da classe das sulfonamidas (Base de Schiff). A segunda parte do permitiu o desenvolvimento de uma metodologia simples (método de screening), rápida, de baixo custo e acima de tudo limpa para determinação de sulfonamidas em amostras de mel, considerando preceitos da Química Verde e com isso reduzir ao máximo a geração de resíduos químicos e o uso de solventes orgânicos. O procedimento de análise que serviu como base para obtenção dos resultados foi a Análise por Injeção em Fluxo (FIA) com o uso de uma cela de longo caminho óptico (b = 100 cm) para detecção espectrofotométrica, permitindo assim um aumento significativo na sensibilidade do método de screening proposto. O sistema de detecção utilizado foi o espectrofotométrico na região do visível através das medidas de absorbâncias, em um comprimento de onda de l = 560 nm, do produto formado entre o analito (sulfaquinoxalina sódica – SQX, sulfadimetoxina – SDX e sulfatiazol - STZ) e...
The analytical determination of antibiotics has been subject increasingly present in chemistry studies, whether its determination to verify the presence medications (with the purpose of comparison with the label) or determination of residues in foods. The first part of this work presents the development of a simple, fast and low cost method, which makes use of the FIA procedure with UV detection to determine the presence of sodium sulphaquinoxaline in samples of three different types of veterinary medicines. The methodology was developed through statistical analysis, optimizing the chemical parameters (concentration) and physical values that provided the best absorbance at l = 560 nm. The chromogenic reagent used was p-DAC in the presence of HCl and SDS form a colored product with the compounds of the class of sulfonamides (Schiff base). The second part of the study aims to develop a simple methodology (screening method), rapid, inexpensive and above all clean for the determination of sulfonamides in honey samples, considering principles of green chemistry and thereby reduce the maximum generation chemical waste and the use of organic solvents. The analysis procedure that will serve as the basis for obtaining the results is the Flow Injection Analysis (FIA) using a cell along the optical path (b = 100 cm) for spectrophotometric detection, thereby allowing a significant increase in sensitivity of the screening method proposed. The detection system will be in the visible region spectrophotometer by measuring absorbance at a wavelength l = 560 nm, the product formed between the analyte (sodium sulphaquinoxaline - SQX, sulfadimethoxine - SDX and sulfathiazole - STZ) and chromogenic reagent (p-dimethylaminocinnamaldehyde - p-DAC), known as Schiff base. The interest in using this method... (Complete abstract click electronic access below)
APA, Harvard, Vancouver, ISO, and other styles
30

Cutri, R. M., F. J. Low, S. G. Kleinmann, E. W. Olszewski, S. P. Willner, B. Campbell, and F. C. Gillett. "SSC 08546+1732: A Faint, Dust-Enshrouded Carbon Star at High Galactic Latitude|A Faint, Dust-Enshrouded Carbon Star at High Galactic Latitude." Steward Observatory, The University of Arizona (Tucson, Arizona), 1988. http://hdl.handle.net/10150/623922.

Full text
Abstract:
During the initial phase of a program to search for sub -stellar candidates at high galactic latitudes in the IRAS Serendipitous Survey Catalog, one source, SSC 08546 +1732, was found to have no optical counterpart on the Palomar Observatory Sky Survey plates. Ground based positional, photometric and spectroscopic observations have identified this source as a heavily dust - enshrouded carbon star, similar to those found in the Galactic plane. The high latitude and relative faintness of this source imply that it lies at a distance of 20 - 50 kpc, and is 10 to 30 kpc out of the plane of the Galaxy. SSC 08546 +1732, along with one other distant obscured carbon star found in the IRAS Point Source Catalog (Low 1987; Beichman e1: al. 1988), represent the first examples of such objects found in the Galactic halo. These stars may either have evolved from population I precursors ejected from the disk, or they may be the first obscured Population II halo carbon stars to be observed. A survey for other distant enshrouded carbon stars in the IRAS Faint Source Catalog should help to elucidate the nature of this new population.
APA, Harvard, Vancouver, ISO, and other styles
31

Catelani, Tiago Augusto. "Desenvolvimento de sistemas de screening automatizados para determinação de sulfonamidas em mel e procedimento limpo para a quantificação de sulfaquinoxalina em medicamentos veterinários /." Araraquara, 2013. http://hdl.handle.net/11449/97842.

Full text
Abstract:
Orientador: Helena Redigolo Pezza
Coorientador: Leonardo Pezza
Banca: Aristeu Gomes Tininis
Banca: Geoffroy Roger Pointer Malpass
Resumo: A determinação de antibióticos tem sido assunto cada vez mais presente nos estudos de química, seja sua determinação para o controle de qualidade dos medicamentos ou determinação de resíduos em alimentos. O trabalho foi desenvolvido em duas etapas. A primeira parte do trabalho permitiu o desenvolvimento de uma metodologia simples, rápida e de baixo custo, onde se faz uso do procedimento de Análise por Injeção em Fluxo (FIA) com detecção espectrofotométrica para averiguar a presença de sulfaquinoxalina sódica em amostras de três tipos diferentes de medicamentos veterinários. A metodologia foi otimizada por planejamento de experimentos. O reagente cromogênico utilizado foi o pdimetilaminocinamaldeído (p-DAC) que na presença de ácido clorídrico (HCl) e o surfactante Dodecilsulfato de sódio (SDS), forma um produto colorido (l = 560 nm) com a compostos da classe das sulfonamidas (Base de Schiff). A segunda parte do permitiu o desenvolvimento de uma metodologia simples (método de screening), rápida, de baixo custo e acima de tudo limpa para determinação de sulfonamidas em amostras de mel, considerando preceitos da Química Verde e com isso reduzir ao máximo a geração de resíduos químicos e o uso de solventes orgânicos. O procedimento de análise que serviu como base para obtenção dos resultados foi a Análise por Injeção em Fluxo (FIA) com o uso de uma cela de longo caminho óptico (b = 100 cm) para detecção espectrofotométrica, permitindo assim um aumento significativo na sensibilidade do método de screening proposto. O sistema de detecção utilizado foi o espectrofotométrico na região do visível através das medidas de absorbâncias, em um comprimento de onda de l = 560 nm, do produto formado entre o analito (sulfaquinoxalina sódica - SQX, sulfadimetoxina - SDX e sulfatiazol - STZ) e... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The analytical determination of antibiotics has been subject increasingly present in chemistry studies, whether its determination to verify the presence medications (with the purpose of comparison with the label) or determination of residues in foods. The first part of this work presents the development of a simple, fast and low cost method, which makes use of the FIA procedure with UV detection to determine the presence of sodium sulphaquinoxaline in samples of three different types of veterinary medicines. The methodology was developed through statistical analysis, optimizing the chemical parameters (concentration) and physical values that provided the best absorbance at l = 560 nm. The chromogenic reagent used was p-DAC in the presence of HCl and SDS form a colored product with the compounds of the class of sulfonamides (Schiff base). The second part of the study aims to develop a simple methodology (screening method), rapid, inexpensive and above all clean for the determination of sulfonamides in honey samples, considering principles of green chemistry and thereby reduce the maximum generation chemical waste and the use of organic solvents. The analysis procedure that will serve as the basis for obtaining the results is the Flow Injection Analysis (FIA) using a cell along the optical path (b = 100 cm) for spectrophotometric detection, thereby allowing a significant increase in sensitivity of the screening method proposed. The detection system will be in the visible region spectrophotometer by measuring absorbance at a wavelength l = 560 nm, the product formed between the analyte (sodium sulphaquinoxaline - SQX, sulfadimethoxine - SDX and sulfathiazole - STZ) and chromogenic reagent (p-dimethylaminocinnamaldehyde - p-DAC), known as Schiff base. The interest in using this method... (Complete abstract click electronic access below)
Mestre
APA, Harvard, Vancouver, ISO, and other styles
32

TAKIGUCHI, Hiromi, Azusa TSUBATA, Makoto MIYATA, Tamao ODAKE, Hiroki HOTTA, Tomonari UMEMURA, and Kin-ichi TSUNODA. "Liquid Core Waveguide Spectrophotometry for the Sensitive Determination of Nitrite in River Water Samples." 日本分析化学会, 2006. http://hdl.handle.net/2237/8755.

Full text
APA, Harvard, Vancouver, ISO, and other styles
33

Dowds, Eileen. "Automated Data Acquisition for Analysis of Fly Ash by Graphite Furnace Atomic Absorption Spectrophotometry." W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539625520.

Full text
APA, Harvard, Vancouver, ISO, and other styles
34

Singh, Daya Bihari. "Assessment of Tissue Oxygenation in the Colon and Prediction of Surgical Site Infections Uisng Spectrophotometry." Thesis, University of Newcastle Upon Tyne, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499338.

Full text
APA, Harvard, Vancouver, ISO, and other styles
35

Azevedo, Luiz Otavio Roffee. "Infra-Red Spectrophotometry and X-Ray Diffractometry as Tools in the Study of Nickel Laterites." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/231213.

Full text
Abstract:
Nickel silicate laterite deposits developed on ultra-mafic rocks are similar in many general respects but they vary considerably in detail. The mineralogy of these surficial deposits is very complex and difficult to determine because of the fine grained nature and solid solution characteristics of the hydrous secondary minerals and because many of the phases are actually mineraloids that are poorly ordered or amorphous. To try some new approaches toward clarification of these phases, 24 samples from New Caledonia and Puerto Rico ranging from the ophiolite-ultramafic olivine-pyroxene-chromite-serpentine substrate rocks upward through intermediate phases of weathering to the final oxide -hydroxide iron cap phase were analyzed with the infrared spectrophotometer (IR -10) and with the automated X –ray diffractometer. Four limonite samples were also mineralogically analyzed. Goethite, secondary quartz, cryptomelane, hematite, chromite, talc, thuringite, and garnierite have been identified in various samples as weathering profile products.
APA, Harvard, Vancouver, ISO, and other styles
36

Ruy, Mayara Regina dos Santos [UNESP]. "Desenvolvimento de sistemas de screening utilizando procedimentos em fluxo para monitoramento de sulfonamidas em urina e produtos de origem animal." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/97811.

Full text
Abstract:
Made available in DSpace on 2014-06-11T19:29:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-21Bitstream added on 2014-06-13T18:38:49Z : No. of bitstreams: 1 ruy_mrs_me_araiq.pdf: 774298 bytes, checksum: f4cf28b55c14f53039b0a2672cb4fbf9 (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Este trabalho propõe um método analítico simples, rápido e de baixo custo para screening (qualitativo/semi-quantitativo) de sulfonamidas em amostras complexas, tais como leite bovino e urina. Para o screening de sulfonamidas em urina e leite bovino foi empregado um procedimento de análise por injeção em fluxo em meio micelar com detecção espectrofotométrica (λ = 555 nm), o qual está baseado na reação entre sulfonamidas e p-dimetilaminocinamaldeído em meio ácido. O uso de meio micelar conferiu ao método grande sensibilidade analítica possibilitando sua aplicação no screening dos analitos alvos de acordo com o valor de limite máximo de resíduo permitido (LMRsulfonamidas = 100 ppb). As condições experimentais para o desenvolvimento do método proposto foram otimizadas com auxílio de planejamento de experimentos. Para validação do método desenvolvido foram avaliados os seguintes parâmetros: exatidão, precisão, limite de detecção (LOD = 3 SDBranco / inclinação da curva analítica), limite de quantificação (LOQ = 10 SDBranco / inclinação da curva analítica) e robustez. O método desenvolvido foi aplicado na análise de sulfonamidas em leite bovino, empregando-se no pré-tratamento das amostras a metodologia QuEChERS. Uma outra aplicação realizada foi a determinação de sulfonamidas em amostras de urina sintética após prévia hidrólise da uréia (interferente) na qual uma leguminosa foi usada como fonte da enzima urease. Em ambas as aplicações, os resultados obtidos foram satisfatórios. O método desenvolvido representa uma alternativa vantajosa em relação a outros métodos disponíveis, pois apresenta baixo custo relativo, além de ser simples, rápido, ambientalmente mais amigável (envolve o baixo consumo de reagentes e amostras) e não requerer procedimentos específicos ou complicados para o preparo das amostras
This work proposes a simple, fast and low cost analytical method for the screening (qualitative / quantitative) of sulfonamides in complex samples, such as urine and bovine milk. The screening of sulfonamides in those samples was proceeded by flow injection analysis in, micellar medium, with spectrophotometric detection (λ = 555 nm). The method is based on the reaction between sulfonamide and p- dimethylaminocinnamaldehyde in acidic medium. The use of micellar media increased the sensitivity of the analytical method allowing its application in the screening of target analytes according to the permitted value of maximum residue level (LMRsulfonamides = 100 ppb). Experimental design methodologies were used to optimize the proposed method. The following parameters were assessed in order to validate the method: accuracy, precision, limit of detection (LOD = 3 SD Blank / inclination of the analytical curve), limit of quantification (LOQ = 10 SD Blank / inclination of the analytical curve) and robustness. The method was applied to the analysis of sulfonamides in bovine milk. Pre-treatment of samples was proceeded by QuEChERS methodology. The method was also applied to the determination of sulfonamides in samples of synthetic urine after previous hydrolysis of urea (interferent); a legume was used as the source of the enzyme urease. In both applications, the results were satisfactory. The method represents an advantageous alternative over other available methods, since it has relatively low cost, besides being simple, rapid, environmentally friendly (it involves a low consumption of reagents and samples) and does not require specific or complicated procedures to prepare the samples
APA, Harvard, Vancouver, ISO, and other styles
37

Crowe, John A. "Optical methods for monitoring physiological and biochemical variables." Thesis, University of Oxford, 1986. http://ora.ox.ac.uk/objects/uuid:c364decd-6a47-45d3-aa5b-2a5a013067ff.

Full text
Abstract:
The use of optical methods for performing non-invasive physiological and biochemical monitoring has been investigated, with particular emphasis on the application of near-infrared spectrophotocetry for following changes in the redox state of cytochrome oxidase. Initial studies of the gross optical properties of in vivo tissue were made using an image intensifier. These demonstrated that some light is transmitted through biological tissues and that such material is very highly scattering. In order to investigate the feasibiity of non-invasively monitoring changes in the redox state of cytochrome oxidase in vivo. spectrophotometric and oxygen measurements were made on solutions containing the pure enzyme and yeast cell suspensions. These demonstrated the high affinity that the enzyme has for oxygen in such preparations, in contrast to the much lower apparent affinities in vivo that have been reported. These results were then modelled mathematically, and a possible-explanation for this anomaly suggested. Potential problems with applying this method are also presented. The interest in cytochrome oxidase is due to its importance in oxidative metabolism. However in performing this role it also assists in the prevention of oxidative damage, whose contribution to various disease states in paediatrics is briefly considered. Two instruments were also constructed, and used, firstly to measure the spectral characteristics of transmitted and reflected light in vivo. ana secondly to study the cardiac synchronous pulsatile component of this light (commonly referred to as the photoplethysmogram).
APA, Harvard, Vancouver, ISO, and other styles
38

Patsavas, Mark. "Improving Spectrophotometric Carbon System Measurements." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5095.

Full text
Abstract:
This work provides improved procedures for spectrophotometric carbon system measurements. Indicator dyes used for routine spectrophotometric pH measurements in seawater suffer from impurity issues, which introduce vendor-specific systematic errors in pH determinations. The magnitude of these errors for several vendors was investigated for meta Cresol Purple (mCP) and Cresol Red (CR). Flash chromatography procedures were developed to obtain purified mCP and CR on a bulk scale in order to supply the oceanographic research community with the indicators. Easy access to the purified indicators ensures global intercomparability of spectrophotometric pH determinations. Internal consistency of marine inorganic carbon system measurements was studied using datasets obtained on two large coastal ocean acidification research cruises. In both cases, purified mCP was used to obtain the pH measurements, thereby improving accuracy relative to previous studies in which measurements were obtained with unrefined mCP. Based on this internal consistency study, recommendations are made for selecting the parameter pairs used for saturation state calculations. Direct spectrophotometric methods for measuring carbonate ion concentrations in seawater were improved by (a) using a higher concentration of lead as the carbonate indicator and (b) altering the carbonate computational algorithm based on high quality field data. Measurements of DIC and pH (using purified mCP) were used to calculate carbonate ion concentrations for comparison with spectrophotometrically measured carbonate ion concentrations (i.e., via spectrophotometric measurements of Pb(II) spectra in the ultraviolet). Minor changes in the computational algorithm substantially improved agreement between measured and calculated carbonate ion concentrations.
APA, Harvard, Vancouver, ISO, and other styles
39

Newkirk, Scott Hunter. "Detection levels of drinking water contaminants using field portable ultraviolet and visible light (uv/vis) spectrophotometry /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/NEWKIRK2005.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
40

Wei, Wenjun. "Wide bore tube electrophoresis using Pluronic polymer gels in conjunction with spectrophotometry, HPLC, and MALDI/MS." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1375056442.

Full text
APA, Harvard, Vancouver, ISO, and other styles
41

Wong, Ming-hong Daniel. "A study of passive sampling and modelling techniques for urban air pollution determination /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2093385X.

Full text
APA, Harvard, Vancouver, ISO, and other styles
42

Villarroel, Cortés Milko Javier. "Avaliação espectrofotométrica de diferentes sistemas cerâmicos /." Araraquara : [s.n.], 2010. http://hdl.handle.net/11449/101384.

Full text
Abstract:
Orientador: Osmir Batista de Oliveira Junior
Banca: José Roberto Cury Saad
Banca: Edson Alves Campos
Banca: Leonardo Busso
Banca: Roberto Elias Campos
Resumo: O objetivo deste trabalho foi avaliar espectrofotometricamente a transmitancia direta e refletância de diferentes sistemas cerâmicos. Foram selecionados 12 sistemas cerâmicos: Grupo I Cercon B (Dentsply); Grupo II Cercon A (Dentsply); Grupo III In-Ceram Alumina (Vita); Grupo IV In-Ceram Spinell (Vita); Grupo V Procera Zirconia 2 (Nobel Biocare); Grupo VI Procera Zirconia 3 (Nobel Biocare); Grupo VII Procera Zirconia 4 (Nobel Biocare); Grupo VIII Procera Zirconia 5 (Nobel Biocare); Grupo IX IPS e.max Press MO (Ivoclar- Vivadent); Grupo X IPS e.max Press HO (Ivoclar-Vivadent); Grupo XI Zirconforce (Cubo) e Grupo XII IPS d.sing (Ivoclar-Vivadent). Utilizou-se um espectrofotômetro para corpos sólidos calibrado para registrar a transmitância da luz com comprimento de onda de 400 a 700nm. Foram confeccionados 5 corpos de prova de infra-estrutura cerâmica (15mm de diâmetro e 0,5mm de espessura) para cada grupo de acordo com a especificações do fabricante. Os valores de transmitância direta foram analisados mediante o teste ANOVA (p<0,05). Pode-se observar que existem diferenças significativas entre os grupos G3, G9 e G12 que apresentaram um comportamento significantemente distinto entre si e entre todos os outros grupos. Não houve diferenças entre os grupos G4, G5, G6, G7, G8, G10 e G11 e entre G1 e G2 para os valores máximos de transmitância. Posteriormente, em uma segunda etapa, os corpos de prova de infra-estrutura foram completados com cerâmicas de cobertura indicada pelo fabricante de cada grupo, obtendo as seguintes dimensões: 15mm de diâmetro e 2mm de espessura. As amostras foram submetidas ao teste de transmitância direta e os resultados foram submetidos ao teste ANOVA (p<0,05). A análise estatística demonstrou diferenças estatísticas entre os grupos em estudo em que G9 e G12 tiveram um comportamento significativamente distinto entre si e com todos os outros grupos... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The aim of this study was to evaluate spectrophotometrically the direct transmittance and reflectance of different ceramic systems. Twelve ceramic systems were selected: Cercon B - Dentsply (Group I), Cercon A - Dentsply (Group II), In-Ceram Alumina - Vita (Group III), In-Ceram Spinell - Vita (Group IV), Zirconia 2 Procera - Nobel Biocare (Group V), Procera Zirconia 3 - Nobel Biocare (Group VI), Zirconia 4 Procera - Nobel Biocare (Group VII), Procera Zirconia 5 - Nobel Biocare (Group VIII), IPS e.max Press MO - Ivoclar-Vivadent (Group IX) and IPS e.max Press HO - Ivoclar-Vivadent (Group X ), Zirconforce - Cubo (Group XI) and IPS d.sing - Ivoclar-Vivadent (Group XII). Spectrophotometer for solids was used calibrated to register in the range of 400 to 700nm. Five ceramic copyings for testing were made (15mm in diameter and 0.5 mm in thickness) for each group according to manufacturer directions. Direct transmittance values were analyzed by ANOVA test (p <0.05). It was observed significant differences between groups G3, G9 and G12 were significantly different behavior between them and all other groups. There were no differences between groups G4, G5, G6, G7, G8, G10, G11 and between G1 and G2 for maximum values of transmittance. In a second stage test bodies were filled with covering ceramic getting the following dimensions: 15mm diameter and 2mm thick. The test bodies were subjected to direct transmittance test and the results were submitted to ANOVA test (p <0.05). Statistical analysis revealed that there were statistical differences between the study groups. G9 and G12 behavior were significantly different between them and all other groups. Same behavior was attributed to groups G5, G6, G7, G8, G10, G11 and between G1 and G2 and between G3 and G4. Finally, complete test bodies were subjected to the reflectance test using the reflectance spectrophotometer CM 2600d (Konica Minolta)... (Complete abstract click electronic access below)
Doutor
APA, Harvard, Vancouver, ISO, and other styles
43

CHEPCANOFF, VERA. "Desenvolvimento de uma metodologia para a separação de samário e európio a partir de mistura de óxidos de terras raras por redução eletroquímica/precipitação." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11443.

Full text
Abstract:
Made available in DSpace on 2014-10-09T12:51:58Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:07:37Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
APA, Harvard, Vancouver, ISO, and other styles
44

Aghamoosa, Mostapha. "The Influence of Solvents on a Gold(I)-Assisted Thiolate_Disulfied Exchange Reaction as Monitored by UV-VIS Spectrophotometry." Fogler Library, University of Maine, 2011. http://www.library.umaine.edu/theses/pdf/AghamoosaM2011.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
45

Cooper, Jeffery W. "Spectrophotometry of rare earth chloride and fluoride complexes in molten salt solutions using a remote high temperature sensor /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3137687.

Full text
APA, Harvard, Vancouver, ISO, and other styles
46

Benez, Rogerio Camargo [UNESP]. "Análise da influência dos movimentos verticais e horizontais das barras de um pulverizador na aplicação da calda." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/90584.

Full text
Abstract:
Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-31Bitstream added on 2014-06-13T18:21:00Z : No. of bitstreams: 1 benez_rc_me_botfca.pdf: 673253 bytes, checksum: e6db77902529da145a32af433aefa3ff (MD5)
Universidade Estadual Paulista (UNESP)
O objetivo deste trabalho foi avaliar os movimentos horizontais e verticais da barra de um pulverizador, operando com e sem o sistema controlador de altura e determinar a influência desses movimentos na deposição da calda. O ensaio foi instalado com oito tratamentos que consistiram nas combinações de duas condições de operação do pulverizador (com e sem o sistema controlador de altura barras - CE e SE, respectivamente) e quatro diferentes condições de superfície para deslocamento do pulverizador (subindo terraço, descendo terraço, superfície plana com e sem obstáculo). Posteriormente, a movimentação da barra foi avaliada através da videografia digital, sendo as imagens analisadas em softwares específicos para o cálculo da amplitude dos deslocamentos horizontais e verticais. Para a determinação da deposição da calda foi utilizado o método da espectrofotometria. O corante Azul Brilhante FDC-1, diluído a 0,3%, foi utilizado como marcador em todos os tratamentos. Foi utilizado um pulverizador Jacto, modelo Columbia AD-18, com barra de 18 metros de comprimento, acoplado a um trator Ford, modelo 6610. A velocidade média de deslocamento do pulverizador foi de 8 Km h-1 em todos os tratamentos. A barra de pulverização foi equipada com 37 bicos, com pontas de jato plano, modelo AVI 11002. O espaçamento entre bicos foi de 0,50 metros e a barra de pulverização trabalhou a uma altura de 0,50 metros em relação...
The aim of this study was to evaluate the horizontal and vertical movements of a sprayer boom, operating with and without the height controller system and determine the influence these movements in the liquid distribution. The test was conducted with eight treatments, consisting in combinations of two operating conditions of the sprayer (with and without the height controller system - CE and SE, respectively) and four different surface conditions for the moving sprayer (rising terrace, down terrace, flat surface and flat surface with obstacle). Subsequently, the sprayer boom movements were measured by digital video recording (videografy). The images were analyzed on specific software for calculating the amplitude of the horizontal and vertical displacements of boom. To determine the liquid deposition it was used the spectrophotometry method. The dye Brilliant Blue FDC-1, diluted to 0,3%, was used as marker in all treatments. It was used a Jacto sprayer boom, model AD-18 Columbia, equipped with a 18 meters sprayer boom, attached to a Ford tractor, model 6610. The driving speed average of the sprayer was 8 km h-1 in all treatments. The sprayer boom was equipped with 37 nozzles with flat spray tips, AVI 11002 type. The nozzle spacing was 0,50 meters and the sprayer boom was positioned at 0,50 meters above the ground. The average flow of the tips was 120 L ha-1, and the pressure of the pump was of 50 psi. The results showed that the height controller system interfered in sprayer boom movements and influenced the liquid deposition. The amplitudes of the vertical and horizontal sprayer boom movements were obtained in proposed treatments and correlated with the amount of deposits on targets surface. These amplitudes showed that the influence of horizontal boom movements were more significant than vertical... (Complete abstract click electronic access below)
APA, Harvard, Vancouver, ISO, and other styles
47

Fernandes, Flávio Cesar Bedatty [UNESP]. "Desenvolvimento de métodos limpos para screening e determinação de sulfonamidas em matrizes diversas." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/97847.

Full text
Abstract:
Made available in DSpace on 2014-06-11T19:29:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-06-20Bitstream added on 2014-06-13T20:59:14Z : No. of bitstreams: 1 fernandes_fcb_me_araiq.pdf: 1102858 bytes, checksum: 4c88e34a40933cd981ce043c3b791166 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Neste trabalho foram desenvolvidos dois métodos ambientalmente mais amigáveis para screening e determinação de sulfonamidas em matrizes diversas. O primeiro método desenvolvido foi o de análise por injeção em fluxo (FIA) com detecção espectrofotométrica, o qual se baseia na reação entre sulfonamidas e o reagente cromogênico p-dimetilaminobenzaldeído (p-DAB - 1,34 x 10-2 mol L-1 ou 0,2 % m/v) em meio ácido (HCl - 2,05 x 10-1 mol L-1) com adição de dodecil sulfato de sódio (SDS - 3,0 x 10-2 mol L-1), o que aumentou significativamente a sensibilidade da reação a qual produz um produto amarelo com λmáx = 465 nm. A configuração escolhida para o sistema FIA foi a de zonas coalescentes empregando um injetor comutador de três peças. Neste caso, são adicionados a reação, volumes fixos da solução contendo o analito e da solução contendo o reagente, sendo estes de 502 e 150 μL, respectivamente, transportados por uma solução carregadora de HCl 5,0 x 10-2 mol L-1 até a confluência. A faixa linear estudada variou entre 0,2 mg L-1 a 5,0 mg L-1 (0,2 - 5,0ppm). Os limites de detecção (LOD) e de quantificação (LOQ) calculados foram entre 0,040 - 0,050 mg L-1 e 0,130 - 0,160 mg L-1, respectivamente. A freqüência analítica obtida foi de 60 análises por hora. O segundo método desenvolvido foi o de espectroscopia de reflectância difusa utilizando spot test. O método é baseado na reação entre sulfonamidas e o reagente cromogênico p-dimetilaminocinamaldeído (2,4 x 10-3 mol L-1 ou 0,042 % m/v) em meio ácido (HCl - 2,0 x 10-2 mol L-1) e SDS (3,5 x 10-2 mol L-1), sobre a superfície de um papel de filtro, produzindo um complexo colorido (λmáx = 560 nm) estável. Para a reação apenas 20 μL de cada solução foi utilizada, sendo um procedimento limpo, pois gera pouco resíduo ao meio ambiente. A faixa linear de...
In this work were developed two environmentally friendly analytical methods for screening and determination of sulfonamides in several matrices. The first method developed was flow injection analysis (FIA) using spectrophotometric determination, which is based on the reaction between sulfonamide and coupling reagent p-dimethylaminobenzaldehyde (1.34 x 10-2 mol L-1 or 0.2 % m/v) in acid medium (HCl - 2.05 x 10-1 mol L-1) with the addition of sodium dodecyl sulfate (SDS - 3.0 x 10-2 mol L-1) what significantly increased the sensitivity of the reaction which yield a yellow product with λmáx = 465 nm. Merging zone configuration employing a three-piece manual injector-commutator was chosen for system FIA. In this case, are added to the reaction, fixed volumes of solution containing the analyte and the solution containing the reagent, the latter being of 502 and 150 μL, respectively, loaded via the porter (5.0 x 10-2 mol L-1) until confluent point. The linear range was 0.2 mg L-1 a 5.0 mg L-1 (0.2 - 5.0 ppm). The limits of detection LOD) and quantification (LOQ) estimated were 0.040 - 0.050 mg L-1 and 0.130 - 0.160 mg L-1, respectively. The average sample rate of 60 determinations per hour. The second method developed was diffuse reflectance spectroscopy using spot test analysis. The method is based on the reaction between sulfonamides and coupling reagent p-dimethylaminocinnamaldeyde (2.4 x 10-3 mol L-1 or 0.042% m/v) in acid medium (HCl - 2.0 x 10-2 mol L-1) and SDS (3.5 x 10-2 mol L-1), on the surface of filter paper, yielding a stable colored product (λ = 560 nm). For the reaction only 20 μL of reagent was applied, it’s a clear procedure, yielding a little quantity of residues. The linear range was 1.0-10.0 mg L-1 (1 - 10 ppm). The limits of detection (LOD) and quantification (LOQ) estimated were 0.140 a 0.200 mg L-1 and... (Complete abstract click electronic access below)
APA, Harvard, Vancouver, ISO, and other styles
48

Gabrielson, Jenny. "Assessing the toxic impact of chemicals using bacteria /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-143-1/.

Full text
APA, Harvard, Vancouver, ISO, and other styles
49

Touhami, Yamina. "Circumstellar Disks Around Rapidly Rotating Be-Type Stars." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/phy_astr_diss/53.

Full text
Abstract:
Be stars are rapidly rotating B-type stars that eject large amounts of material into a circumstellar disk. Evidence of the presence of a disk is found through hydrogen emission lines in their spectra, IR excess flux, and linear intrinsic polarization. In this dissertation, we report the first simultaneous interferometric and spectroscopic observations of circumstellar disks around 24 bright Be stars made using the techniques of long baseline interferometry and moderate resolution spectroscopy in the near infrared. The goal of the project is to characterize the fundamental geometrical and physical properties of the emitting regions that are responsible for the IR flux excesses detected in the K-band in our sample stars. This observational work has been conducted with both the Center for High Angular Resolution Astronomy (CHARA) Array at Mount Wilson Observatory, and the Mimir spectrograph at Lowell Observatory. The visibility measurements were interpreted with different geometrical and physical disk models in order to determine the spatial extension of the disk, the inclination angle, the position angle, and the density profile of the disk. We find that the spatial extension of the circumstellar disk in the K-band is only about a few stellar radii, and that the density structure of the disk is consistent with a radially decreasing function with a density exponent that ranges between 2.5 and 3.5. The resulting disk densities are in a good agreement with those derived from the Infrared Astronomical Satellite (IRAS) measurements, and the resulting disk geometries are consistent with previous polarimetric measurements. We find that the K-band sizes of the emitting regions in the disk are smaller by a factor of two than the Hα sizes, and we show that this is due to the lower opacity of the continuum in the disk. By combining recent measurements of the projected rotational velocities with the disk inclination angles derived from interferometry, we were able to estimate the actual equatorial linear rotational velocities of the Be stars in our sample. The obtained linear rotational velocities indicate that Be stars are rapid rotators with an equatorial velocity that is about 0.7 - 0.9 of their critical velocities.
APA, Harvard, Vancouver, ISO, and other styles
50

Lima, Débora Alves Nunes Leite 1978. "Avaliação de diferentes catalisadoores no clareamento dental : estudo in vitro." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289455.

Full text
Abstract:
Orientador: Jose Roberto Lovadino
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-11T12:44:55Z (GMT). No. of bitstreams: 1 Lima_DeboraAlvesNunesLeite_D.pdf: 595978 bytes, checksum: 9c2784969f094e3cb150fb69f46744b1 (MD5) Previous issue date: 2008
Resumo: O objetivo deste estudo ¿in vitro¿ foi avaliar a eficácia do clareamento dental através da utilização de um gel contendo peróxido de hidrogênio em alta concentração associado a diferentes agentes catalisadores físicos e químicos. Para isso, o estudo foi dividido em 2 experimentos. Experimento 1- avaliou a eficácia do clareamento após tratamento com peróxido de hidrogênio 35 % (Whiteness HP Maxx) ativado por diferentes fontes de luz: Lâmpada halógena (no modo convencional e clareamento) (Optilux 501C, Demetron/Kerr), LED 1° geração (Ultrablue IV, DMC), LED/ laser de diodo (Ultrablue IV, DMC), LED 2° geração (no modo alta potência) (Bluephase 16i, Ivoclar Vivadent) e nenhuma fonte de luz (grupo controle); Experimento 2- avaliou a eficácia do clareamento em consultório ativado com catalisadores químicos e/ou físico: G1- peróxido de hidrogênio 35 % (Whiteness HP Maxx) + 20 % hidróxido de sódio; G2- peróxido de hidrogênio 35 % + 7 % bicarbonato de sódio; G3- peróxido de hidrogênio 38 % (Opalescence Xtra Boost); G4: peróxido de hidrogênio 35 % + lâmpada halógena; G5: peróxido de hidrogênio 35 % + 20 % hidróxido de sódio + lâmpada halógena; G6: peróxido de hidrogênio 35 % + 7 % bicarbonato de sódio + lâmpada halógena; G7: peróxido de hidrogênio 38 % + lâmpada halógena e G8: peróxido de hidrogênio 35 %. Para tanto, fragmentos dentais foram obtidos de terceiros molares humanos e aleatoriamente distribuídos em grupos (n=5) de acordo com o tratamento estipulado. A eficácia do clareamento foi avaliada através de um espectrofotômetro. Para tratar os fragmentos, foram realizadas três sessões de clareamento (sessões 1 a 3). Os resultados foram submetidos à Análise de Variância, seguido do Teste de Tukey (p<0,05). Verificou-se que, para ambas as fases, os grupos ativados e não ativados pelos diferentes sistemas catalisadores não diferiram significativamente entre si. Dessa forma, os sistemas catalisadores não melhoraram a efetividade do tratamento clareador de alta concentração
Abstract: The aim of this in vitro study was to evaluate the bleaching efficacy of high concentration bleaching agents activated by chemical or physical catalysts. For this, this study was divided in two parts: Experiment 1- evaluated the efficacy of tooth whitening after treatment with 35 % hydrogen peroxide (Whiteness HP Maxx) activated by different light-curing units: Halogen lamp (Conventional and Bleach mode) (Optilux 501C, Demetron/Kerr), LED 1st generation (Ultrablue IV, DMC), LED/ diode laser (Ultrablue IV, DMC), LED 2nd generation (Bluephase 16i, Ivoclar Vivadent) , and no light source (control group); Experiment 2- analysis of chemical and physical catalysts: G1- 35 % hydrogen peroxide (Whiteness HP Maxx) + 20 % sodium hydroxide; G2- 35 % hydrogen peroxide + 7 % sodium bicarbonate; G3- 38 % hydrogen peroxide (Opalescence Xtra Boost); G4: 35 % hydrogen peroxide + Halogen lamp; G5: 35 % hydrogen peroxide + 20 % sodium hydroxide + halogen lamp; G6: 35 % hydrogen peroxide + 7 % sodium bicarbonate + halogen lamp; G7: 38 % hydrogen peroxide + halogen lamp and G8: 35 % hydrogen peroxide. Blocks obtained from human molars were randomly divided into groups (n=5) in accordance with bleaching treatments. The efficacy of bleaching was measured using a spectrophotometer. Three bleaching sessions were performed (sessions 1 to 3). The results were submitted to ANOVA followed by the Tukey test (p<0.05). For both experiments, activated vs. non-activated bleaching did not differ significantly for all the times tested. In conclusion, the activating systems did not improve the whitening effectiveness
Doutorado
Dentística
Doutor em Clínica Odontológica
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography