Academic literature on the topic 'Halogen light. eng'
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Journal articles on the topic "Halogen light. eng"
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Bobrowski, N., and G. Giuffrida. "Bromine monoxide/sulphur dioxide ratios in relation to volcanological observations at Mt. Etna 2006–2009." Solid Earth Discussions 4, no. 1 (March 16, 2012): 475–505. http://dx.doi.org/10.5194/sed-4-475-2012.
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Abstract. Over a three year period, from 2006 to 2009, frequent scattered sun light DOAS measurements were conducted at Mt. Etna in a distance of around six kilometres downwind from the summit craters. During the same period and in addition to these measurements, volcanic observations were made by regularly visiting various parts of Mt. Etna. Results from these measurements and observations are presented and their relation is discussed. The focus of the investigation is the bromine monoxide/sulphur dioxide (BrO/SO2) ratio, and its variability in relation to volcanic processes. That the halogen/sulphur ratio can serve as a precursor or indicator for the onset of eruptive activity was already proposed by earlier works (e.g. Noguchi and Kamiya, 1963; Menyailov, 1975; Pennisi and Cloarec, 1998; Aiuppa, 2002). However, there is still a limited understanding today because of the complexity with which halogens are released, depending on magma composition and degassing conditions. Our understanding of these processes is far from complete, for example of the rate and mechanism of bubble nucleation, growth and ascent in silicate melts (Carroll and Holloway, 1994), the halogen vapour-melt partitioning and the volatile diffusivity in the melt (Aiuppa et al., 2009). With this study we aim to add one more piece to the puzzle of what halogen/sulphur ratios might tell about volcanic activities. Our data set shows an increase of the BrO/SO2 ratio several weeks prior to an eruption, followed by a decline before and during the initial phase of eruptive activities. Towards the end of activity or short afterwards, the ratio increases to baseline values again and remains more or less constant during quiet phases. To explain the observed evolution of the BrO/SO2 ratio, a first empirical model is proposed. This model suggests that bromine, unlike chlorine and fluorine, is less soluble in the magmatic melt than sulphur. By using the DOAS method to determine SO2, we actually observe most of the emitted sulphur of Mt. Etna. Regarding bromine however, we are aware that by determining only the bromine monoxide (BrO) radical we might just observe a small or even a variable fraction of the total emitted bromine. Therefore we present first studies to justify the assumption that despite the disadvantage just mentioned, the BrO/SO2 ratio can nevertheless serve as a new parameter to indicate the state of a volcano, when measurements are conducted under certain, but rather convenient conditions.
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Beriat, Nilufer Celebi, Ahmet Atila Ertan, Senay Canay, Aylin Gurpinar, and Mehmet Ali Onur. "Effect of Different Polymerization Methods on the Cytotoxicity of Dental Composites." European Journal of Dentistry 04, no. 03 (July 2010): 287–92. http://dx.doi.org/10.1055/s-0039-1697841.
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Objectives: The aim of this study was to compare the cytotoxic effects of various dental composites polymerized with two different curing units.Methods: Disc-shaped test samples of composites Filtek Z250, Filtek A110, Filtek P60, Filtek Supreme, and SDI Rok were polymerized using one quartz tungsten halogen (QTH) and one light emitting diode (LED) light curing unit (LCU), namely Optilux 501 (QTH) and Elipar Freelight 2 (LED). L-929 mouse fibroblast cultures (3x104 cells/ml) were incubated with the samples in 96 well culture plates for evaluation after 8, 24, 48, 72 h. At the end of each period, the cells were counted and examined under a light microscope, and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay was performed. The degree of cytotoxicity for each sample was determined according to the reference value represented by the cells in a control group (a culture without sample).Results: A significant 3 factor interaction occurred among LCUs, composites, and time factors (P<.005). In general, the test materials cured with the LED LCU demonstrated higher cell survival rates when compared with those cured with halogen LCUs.Conclusions: This study shows that polymerization of dental composites with a light emitting diode LCU positively influences the L-929 mouse fibroblast cell viability. (Eur J Dent 2010;4:287-292)
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Hasegawa, Eietsu, Kazuma Mori, Shiori Tsuji, Kazuki Nemoto, Taku Ohta, and Hajime Iwamoto. "Visible Light-Promoted Metal-Free Reduction of Organohalides by 2-Naphthyl or 2-Hydroxynaphthyl-Substituted 1,3-Dimethylbenzimidazolines." Australian Journal of Chemistry 68, no. 11 (2015): 1648. http://dx.doi.org/10.1071/ch15396.
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The visible light-promoted reduction reactions of some organohalides were investigated using 2-aryl-1,3-dimethylbenzimidazolines (Ar-DMBIH) possessing 2-naphthyl or 2-hydroxynaphthyl substituents. In these reduction reactions, single-electron transfer from photo-excited Ar-DMBIH, attained by Xe lamp irradiation through an appropriate glass-filter (λ > 390 nm), to the halide substrates leads to the carbon–halogen bond cleavage, followed by the rearrangements of the formed carbon radicals such as 5-exo hexenyl cyclization and the Dowd–Beckwith ring expansion. Addition of 1,8-diazabicyclo[5.4.0]undec-7-ene was found to enhance the reducing ability of hydroxynaphthyl-substituted DMBIH. A household white light-emitting diode was also used as a light source for these reactions.
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Gheorghian, Adina-Teodora, Valentin Apostol, Tudor Prisecaru, Camelia Stanciu, and Horaţiu Pop. "Irradiance characteristic of a small-scale solar simulator for testing thermal collectors." E3S Web of Conferences 112 (2019): 02012. http://dx.doi.org/10.1051/e3sconf/201911202012.
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This paper describes the development of a small-scale solar simulator for research and educational purposes. The main goal is to provide a uniform and stable distribution of irradiation from a set of four floodlight halogen lamps, over a targeted area of 40x40 cm2. The floodlights are placed perpendicularly to each other, on the top end of a light tube. Two types of halogen lamps were characterised and the total irradiation of the solar simulator was measured over a 5x5 grid. The results showed that the two arrangements of lamps are able to achieve a level of 1000 W/m2 on the 40x40 cm2 targeted area, but the non-uniformity is unsatisfactory. In order to reach a non-uniformity level of 10% using the proposed lamps arrangements, the targeted area should be reduced to 31x31 cm2.
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Donchev, Alexander, M. Galetz, and M. Schütze. "Effective Fluorine Treatment for Improved High Temperature Oxidation Behavior of Novel Cu, Mo and Si Containing TiAl-Alloys." Materials Science Forum 783-786 (May 2014): 1117–22. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.1117.
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Intermetallic light weight TiAl-alloys are expected to replace the heavy Ni-based super alloys in several high temperature applications. However until now they cannot be used at temperatures above 700°C for longer times due to their insufficient oxidation resistance. The high temperature oxidation behavior can be improved drastically for the use at temperatures up to at least 1050°C by small amounts of fluorine in the surface region of TiAl-components. A thin protective alumina layer is formed after an optimized fluorine treatment during exposure in oxidizing high temperature environments. Results of isothermal and thermocyclic high temperature oxidation tests of untreated and halogen treated TiAl-samples of new types of TiAl-alloys containing Mo, Cu and Si will be presented in this paper. These results will be compared and discussed considering the beneficial effect of fluorine for a later use as e.g. turbine blades in jet engines. Key words: Titanium aluminides, high temperature oxidation, halogen effect,
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Casselli, Denise Sá Maia, Claudia Cia Worschech, Luis Alexandre Maffei Sartini Paulillo, and Carlos Tadeu dos Santos Dias. "Diametral tensile strength of composite resins submitted to different activation techniques." Brazilian Oral Research 20, no. 3 (September 2006): 214–18. http://dx.doi.org/10.1590/s1806-83242006000300006.
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The aim of this study was to evaluate the diametral tensile strength (DTS) of composite resins submitted to different curing techniques. Four composite resins were tested in this study: Targis (Ivoclar), Solidex (Shofu), Charisma (Heraeus-Kulzer) and Filtek Z250 (3M Espe). Sixty-four cylindrical specimens were prepared and divided into eight groups according to each polymerization technique (n = 8). The indirect composite resins (Targis and Solidex) were polymerized with their respective curing systems (Targis Power and EDG-lux); Charisma and Filtek Z250 were light-cured with conventional polymerization (halogen light) and additionally, with post-curing systems. Specimens were stored in artificial saliva at 37°C for one week. DTS tests were performed in a Universal Testing Machine (0.5 mm/min). The data were statistically analyzed by ANOVA and Duncan tests. The results were (MPa): Z250/EDG-lux: 69.04ª; Z250/Targis Power: 68.57ª; Z250/conventional polymerization: 60.75b; Charisma/Targis Power: 52.34c; Charisma/conventional polymerization: 49.17c; Charisma/EDG-lux: 47.98c; Solidex: 36.62d; Targis: 32.86d. The results reveal that the post-cured Z250 composite resin showed the highest DTS means. Charisma composite presented no significant differences when activation techniques were compared. Direct composite resins presented higher DTS values than indirect resins.
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Kim, Y. R., G. Martin, L. Paseltiner, H. Ansley, L. Ornstein, and R. J. Kanter. "Subtyping lymphocytes in peripheral blood by immunoperoxidase labeling and light scatter/absorption flow cytometry." Clinical Chemistry 31, no. 9 (September 1, 1985): 1481–86. http://dx.doi.org/10.1093/clinchem/31.9.1481.
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Abstract Lymphocyte subpopulations in a whole-blood sample can be detected by adapting mouse monoclonal antibodies (MAbs) and peroxidase (EC 1.11.1.7) labeling to a flow cytometer equipped with a tungsten-halogen light source and scatter/absorption optics (Technicon H6000). In the optimized cytochemical conditions each cell population generates a distinct, well-separated cluster, for accurate "thresholding" of the surface-antigen negative and positive lymphocyte populations in the presence of other leukocytes. After reaction with MAb, the erythrocytes are lysed, and the lymphocytes and other leukocytes are fixed. Biotinylated anti-mouse IgG, used as a bridge, amplifies the response from the avidin-peroxidase label. Granulocytes and monocytes, which have high endogenous peroxidase activity, and the labeled lymphocytes are stained in a specific amount of hydrogen peroxide plus 4-chloro-1-naphthol in 4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid buffer. Accuracy and precision are equivalent to those of flow cytometers that measure immunofluorescence (e.g., Ortho Spectrum III), as demonstrated with OKT3, OKT4, OKT8, OKT11, and Leu 12 MAbs.
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Krzemien, Wojciech, Monika Rohlickova, Miloslav Machacek, Veronika Novakova, Jaroslaw Piskorz, and Petr Zimcik. "Tuning Photodynamic Properties of BODIPY Dyes, Porphyrins’ Little Sisters." Molecules 26, no. 14 (July 10, 2021): 4194. http://dx.doi.org/10.3390/molecules26144194.
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The photodynamic properties of a series of non-halogenated, dibrominated and diiodinated BODIPYs with a phthalimido or amino end modification on the phenoxypentyl and phenoxyoctyl linker in the meso position were investigated. Halogen substitution substantially increased the singlet oxygen production based on the heavy atom effect. This increase was accompanied by a higher photodynamic activity against skin melanoma cancer cells SK-MEL-28, with the best compound reaching an EC50 = 0.052 ± 0.01 µM upon light activation. The dark toxicity (toxicity without light activation) of all studied dyes was not detected up to the solubility limit in cell culture medium (10 µM). All studied BODIPY derivatives were predominantly found in adiposomes (lipid droplets) with further lower signals colocalized in either endolysosomal vesicles or the endoplasmic reticulum. A detailed investigation of cell death indicated that the compounds act primarily through the induction of apoptosis. In conclusion, halogenation in the 2,6 position of BODIPY dyes is crucial for the efficient photodynamic activity of these photosensitizers.
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MAUGHAN, CURTIS, EDGAR CHAMBERS IV, SANDRIA GODWIN, and DELORES CHAMBERS. "Changes in Lighting Source Can Produce Inaccurate Assessment of Visual Poultry Doneness and Induce Consumers To Eat Undercooked Ground Turkey Patties." Journal of Food Protection 82, no. 3 (February 27, 2019): 528–34. http://dx.doi.org/10.4315/0362-028x.jfp-18-392.
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ABSTRACT Undercooked poultry is a potential source of foodborne pathogens, such as Salmonella and Campylobacter. The best way to avoid eating undercooked poultry is to use a food thermometer during cooking. However, consumers who cook poultry often use visual appearance for determining doneness, which relies on extrinsic factors, including lighting conditions. Because the United States recently mandated changes in lighting to promote energy conservation, this study evaluated the effect of lighting sources on consumer perceptions of doneness and willingness to eat cooked poultry patties. Consumers (n = 104) evaluated validated photographs of turkey patties cooked to different end point temperatures (57 to 79°C) and rated the level of perceived doneness and willingness to eat each sample. Evaluations were conducted under different lighting sources: incandescent (60 W, soft white), halogen (43 W, soft white), compact fluorescent lamp (13 W, soft white), light-emitting diode (LED; 10.5 W, soft white), and daylight LED (14 W). Lighting changed perception of doneness and willingness to eat the patties, with some of the energy-efficient options, such as LED and halogen making samples appear more done than they actually were, increasing the willingness to eat undercooked samples. This poses a risk of consuming meat that could contain bacteria not killed by heat treatment. Recent changes in lighting regulations can affect lighting in homes that affects perceptions of poultry doneness, requiring that educators place extra emphasis on the message that properly using a meat thermometer is the only way to ensure meat is cooked to a safe end point temperature.
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Wu, Chih Wei, Yung Kang Shen, Yi Lung Lee, Chung Sheng Wei, and Chun Ching Hsiao. "The Study of Fabrication of the Liquid Core Waveguide Nutrient Sensor." Key Engineering Materials 364-366 (December 2007): 425–30. http://dx.doi.org/10.4028/www.scientific.net/kem.364-366.425.
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A novel nutrient sensor using liquid core waveguide technique is reported, implementing Teflon AF 1601S coated microchannels. Straight PDMS microchannels replicated from a master were coated with Teflon AF 1601S and sealed with a Teflon AF 1601S coated Pyrex 7740 wafer. It formed a liquid core waveguide with a low index of refraction channel in which a high index aqueous solution was flowed. Light generated by a fiber-coupled tungsten halogen lamp propagated by total internal reflection to the end of the channel where the light was detected using a CCD array spectrometer. There is a dramatic difference between channels with and without a Teflon coating. The absorbance response of this sensor varies linearly with concentration. This innovative technique provides a potentially low-cost and high efficient approach to fill the inspection technology gap between in-situ and laboratory analyses. It is believed that the novel process is expected to give an impact to the aqueous inspection and to create a highly value-added technology in optical test, measurement industry.
Dissertations / Theses on the topic "Halogen light. eng"
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Queiroz, Renato Souza. "Influência da fonte de luz fotoativadora nas propriedades ópticas de resína composta, em função da cor, espessura e tempo de armazenamento /." Araraquara: [s.n.], 2010. http://hdl.handle.net/11449/100992.
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Orientador: Sizenando de Toledo Porto NetoBanca: Alberto Magno Gonçalvez
Banca: Sicknan Soares da Rocha
Banca: José Roberto Cury Saad
Banca: Marcelo Ferrarezi de Andrade
Resumo: Esse estudo se propõe a avaliar as propriedades ópticas (Fluorescência e Absorbância) da resina composta fotoativada (4 SEASONS®) utilizando aparelho fotopolimerizador convencional (luz Halógena Ulttralux - DabiAtlant), e aparelho emissor de Diodo (Radii - SDI e Ultralume Led 5- Ultradent), em função da fonte de luz foto-ativadora, cor, espessura e tempo de armazenamento em saliva artificial. Foram confeccionadas 5 amostras (10,0x1,0 mm) para cada grupo experimental. Para a realização do teste de Absorbância foi utilizado aparelho espectrofotômetro de luz visível (Diode Array Spectrophotometer, HP - Serial Number: 8452-A). Para a obtenção dos valores de fluorescência emitida pelas amostras, foi utilizado espectrofotômetro (SPEX TRIAX FLUOROLOG 3, Jobin Yvon - Serial Number: 0135B-3-99). Os resultados foram julgados estatisticamente conforme a interação entre os fatores de avaliação nos distintos trabalhos. Pode-se concluir que a fonte de luz fotoativadora influenciou apenas a emissão fluorescente da resina de cor TC, não tendo efeito negativo na absorbância; o aumento na espessura da amostra acarretou uma diminuição na emissão fluorescente e na absorbância de todas as cores da resina, independente da fonte de luz; e as diferentes cores da resina exibiram diferentes emissões fluorescentes e absorbância...
Abstract: The arm of this study is to evaluate optical properties (fluorescence and Absorbance) of a composite resin (4 SEASONS®) using light curing units (LCUs)-(QTH - Ulttralux - DabiAtlant and LEDs Radii - SDI and Ultralume Led 5- Ultradent) in function of LCUs, shade, thickness and storage times. 5 samples were prepared for each experimental group. To perform the Absorbance test, was used of UV-Vis spectrophotometer (Diode Array Spectrophotometer, HP - Serial Number: 8452-A). To obtain the fluorescence emission by samples, we used a spectrophotometer (SPEX TRIAX FLUOROLOG 3, Jobin Yvon - Serial Number: 0135B-3-99). The results were deemed statistically as the interaction between the evaluation factors in the different works. It can be concluded that the LCUs only influenced the fluorescent emission of resin color TC, having no negative effect on the absorbance; the increase in thickness of the sample decrease the fluorescent emission and absorbance for colors of the resin, independent of the LCUs; different colors of resin exhibited different fluorescent emission and absorbance.
Doutor
Book chapters on the topic "Halogen light. eng"
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Hendry, Robin Findlay. "Natural Kinds in Chemistry." In Essays in the Philosophy of Chemistry. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780190494599.003.0019.
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Chemical substances such as gold and water provide paradigm examples of natural kinds: They are so central to philosophical discussions on the topic that they often provide the grounds for quite general philosophical claims—in particular that natural kinds must be hierarchical, discrete, and independent of interests. In this chapter I will argue that chemistry in fact undermines such claims. In what follows I will (i) introduce the main kinds of chemical kinds, namely chemical substances and microstructural species; (ii) critically examine some general criteria for being a natural kind in the light of how they apply to chemical kinds; and finally (iii) present two broad theories of how chemical substances are individuated. The primary purpose of this article is to bring scientific detail and sophistication to a topic—natural kinds—which has a long but not always honorable history in philosophy, but chemists can also learn something from these discussions. Chemistry is in the business of making general claims about substances, a fact which is embodied in the periodic table, as well as in the systems of nomenclature and classification published by the International Union of Pure and Applied Chemistry (IUPAC). At several points in the history of their subject, chemists appear to have faced choices about which general categories should appear in these systems. Understanding why these choices were made, and the alternatives rejected, gives us an insight into whether chemistry might have developed differently. This is central to understanding why chemistry looks the way it does today. So, what are the chemical kinds? Chemists study the structure and behavior of substances such as gold, water and benzene, and also of microscopic species such as gold atoms, and water and benzene molecules. They group together higher kinds of substances: groups of elements such as the halogens and alkali metals, broader groups of elements such as the metals, and classes of compounds that share either an elemental component (e.g., chlorides), a microstructural feature (e.g., carboxylic acids), or merely a pattern of chemical reactivity (e.g., acids).