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1
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.
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Marshall, J. E. A. "A simple cost-effective infra-red microscope for palynology." Journal of Micropalaeontology 14, no. 2 (October 1, 1995): 106. http://dx.doi.org/10.1144/jm.14.2.106.
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Abstract. It has long been known that objects which are opaque in transmitted white light can become translucent in infra-red (IR) light. Its application to palynology was shown by Leclercq (1933) who used an IR filter to cut out the visible light from the specimen coupled with an IR-sensitive film to capture the image. Although the significance of this development was recognized (Walton, 1935), it was never generally used since oxidative methods such as Schulze’s solution are normally successful in clearing exines. The exceptions are opaque palynomorphs from thermally over-mature rocks. Such assemblages have been studied with IR microscopy using either IR-sensitive film on partially cleared material (e.g. Tiwari & Schaarschmidt, 1975) or electronic IR imaging systems (Cramer & Diez, 1972).The technical sophistication and performance of IR imaging microscopes has recently improved significantly following their routine application for the internal imaging of silicon chips. However, such microscopes are designed for use in reflected light and also rather costly. In addition their design makes them difficult to routinely switch from brightfield transmitted light to IR light without risk of damaging their sensitive IR tube. This note describes a simplified IR microscope for transmitted light which shows how excellent images of opaque spores in the near-IR can be produced using the simplest palynological microscope.This IR microscope is based around an Olympus BHSM-IR system. This is fitted with a 100W quartz halogen bulb which is essential for providing the required level of IR illumination. However, the only specific IR corrected optics this. . .
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Lee, Suzanne E., Walter W. Wierwille, and Maryanne C. DeHart. "Evolution of an Enhanced Rear Signaling System." Transportation Research Record: Journal of the Transportation Research Board 1843, no. 1 (January 2003): 31–40. http://dx.doi.org/10.3141/1843-05.
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Rear-end crashes are the most frequently occurring type of crash, making up approximately 25% of all crashes. Crash analysis has revealed a need to detect stopped and slowing lead vehicles with peripheral vision, as well as to detect stopped and slowing lead vehicles with foveal vision more quickly. Two experiments were conducted in an effort to develop systems that have these properties, yet do not have too much discomfort glare. Both experiments used the same four dependent measures: attention-getting rating, discomfort-glare rating, horizontal peripheral detection angle, and diagonal peripheral detection angle. Experiment 1 examined 17 candidate systems, all using white light and clear lenses. The results showed that the TCL, a lamp with a motorized reflector that moves in an M-sweep pattern, was the top candidate for an imminent crash warning signal, while a pair of centrally located alternating halogen lamps would be optimal for a stopped or slowly moving vehicle signal. Experiment 2 examined the effect of colored lenses for the top four configurations identified from Experiment 1. The results showed that TCL is superior to the alternating pair configurations in attention getting and peripheral detection for an imminent crash warning signal, with glare reduced by the use of tinted lenses in either red or amber. The high-output halogen alternating pair with either amber or red dispersive lenses represents the best available configuration for the stopped or slowly moving vehicle signal.
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Schütze, Michael, and Simone Friedle. "Oxidation Behavior of Intermetallic Titanium Aluminide Alloys." MRS Proceedings 1516 (2012): 77–88. http://dx.doi.org/10.1557/opl.2012.1666.
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ABSTRACTAbove 750-800°C oxidation becomes a serious life time issue for the new group of intermetallic light-weight high temperature alloys based on titanium aluminides (TiAl). Fast growing titanium oxide competes with protective alumina as a surface scale in the oxidation reaction by which the formation of a slow-growing protective oxide scale is prevented. The key to the development of alloys with sufficient oxidation resistance is the understanding of the thermodynamic and kinetic situation during the oxidation process. The latter is influenced by the type of alloying elements, the Al- and Ti-activities in the alloy, the oxidation temperature and the environment (e.g. dry or humid air, etc.). This paper provides a comprehensive summary of the oxidation mechanisms and the parameters influencing oxide scale formation. Besides the role of metallic alloying elements, the halogen effect will also be discussed. The paper finishes with recent results concerning the prevention of oxidation-induced room temperature embrittlement of TiAl alloys.
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Chakraborty, Arnab, Prasun Dutta, Abhirup Datta, and Nirupam Roy. "The study of the angular and spatial distribution of radio-selected AGNs and star-forming galaxies in the ELAIS N1 field." Monthly Notices of the Royal Astronomical Society 494, no. 3 (April 9, 2020): 3392–404. http://dx.doi.org/10.1093/mnras/staa945.
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ABSTRACT The cosmic evolution of bias of different source populations with underlying dark matter density field in post-reionization era can shed light on large-scale structures. Studying the angular and spatial distribution of different compact sources using deep radio catalogue at low frequency is essential to understand the matter distribution of the present Universe. Here, we investigate the relationship of luminous matter with their host dark matter haloes by measuring the angular and spatial clustering of sources (two-point statistics), using deep radio observation of ELAIS N1 (EN1) field with upgraded Giant Metrewave Radio Telescope (uGMRT) at 300–500 MHz. We also analyse the 612 MHz GMRT archival data of the same field to understand the cosmic evolution of clustering of different source populations. We classify the sources as star-forming galaxies (SFGs) and active galactic nuclei (AGNs) based on their radio luminosity. We find that the spatial clustering length and bias to the dark matter density field of SFGs are smaller than AGNs at both frequencies. This proves that AGNs are mainly hosted by massive haloes and hence strongly clustered. However, a small decrease in the bias for both kind of sources at higher frequency indicates that we are most likely tracing the faint objects residing in less-massive haloes at higher frequencies. Our results are in excellent agreement with previous findings at radio and multifrequency surveys. However, comparison with SKADS simulation suggests that the halo mass for different populations used in the simulation is systematically lower. This work quantifies the spatial distribution of extragalactic compact objects in EN1 field and bridges the gap between shallow and deep surveys.
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Lehr, Daniela, Markus R. Wagner, Johanna Flock, Julian S. Reparaz, Clivia M. Sotomayor Torres, Alexander Klaiber, Thomas Dekorsy, and Sebastian Polarz. "A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials." Beilstein Journal of Nanotechnology 6 (November 18, 2015): 2161–72. http://dx.doi.org/10.3762/bjnano.6.222.
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Numerous applications in optoelectronics require electrically conducting materials with high optical transparency over the entire visible light range. A solid solution of indium oxide and substantial amounts of tin oxide for electronic doping (ITO) is currently the most prominent example for the class of so-called TCOs (transparent conducting oxides). Due to the limited, natural occurrence of indium and its steadily increasing price, it is highly desired to identify materials alternatives containing highly abundant chemical elements. The doping of other metal oxides (e.g., zinc oxide, ZnO) is a promising approach, but two problems can be identified. Phase separation might occur at the required high concentration of the doping element, and for successful electronic modification it is mandatory that the introduced heteroelement occupies a defined position in the lattice of the host material. In the case of ZnO, most attention has been attributed so far to n-doping via substitution of Zn2+ by other metals (e.g., Al3+). Here, we present first steps towards n-doped ZnO-based TCO materials via substitution in the anion lattice (O2− versus halogenides). A special approach is presented, using novel single-source precursors containing a potential excerpt of the target lattice 'HalZn·Zn3O3' preorganized on the molecular scale (Hal = I, Br, Cl). We report about the synthesis of the precursors, their transformation into halogene-containing ZnO materials, and finally structural, optical and electronic properties are investigated using a combination of techniques including FT-Raman, low-T photoluminescence, impedance and THz spectroscopies.
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Behroozi, Peter, Charlie Conroy, Risa H. Wechsler, Andrew Hearin, Christina C. Williams, Benjamin P. Moster, L. Y. Aaron Yung, et al. "The Universe at z > 10: predictions for JWST from the universemachine DR1." Monthly Notices of the Royal Astronomical Society 499, no. 4 (October 14, 2020): 5702–18. http://dx.doi.org/10.1093/mnras/staa3164.
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ABSTRACT The James Webb Space Telescope (JWST) is expected to observe galaxies at z > 10 that are presently inaccessible. Here, we use a self-consistent empirical model, the universemachine, to generate mock galaxy catalogues and light-cones over the redshift range z = 0−15. These data include realistic galaxy properties (stellar masses, star formation rates, and UV luminosities), galaxy–halo relationships, and galaxy–galaxy clustering. Mock observables are also provided for different model parameters spanning observational uncertainties at z < 10. We predict that Cycle 1 JWST surveys will very likely detect galaxies with M* > 107 M⊙ and/or M1500 < −17 out to at least z ∼ 13.5. Number density uncertainties at z > 12 expand dramatically, so efforts to detect z > 12 galaxies will provide the most valuable constraints on galaxy formation models. The faint-end slopes of the stellar mass/luminosity functions at a given mass/luminosity threshold steepen as redshift increases. This is because observable galaxies are hosted by haloes in the exponentially falling regime of the halo mass function at high redshifts. Hence, these faint-end slopes are robustly predicted to become shallower below current observable limits (M* < 107 M⊙ or M1500 > −17). For reionization models, extrapolating luminosity functions with a constant faint-end slope from M1500 = −17 down to M1500 = −12 gives the most reasonable upper limit for the total UV luminosity and cosmic star formation rate up to z ∼ 12. We compare to three other empirical models and one semi-analytic model, showing that the range of predicted observables from our approach encompasses predictions from other techniques. Public catalogues and light-cones for common fields are available online.
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Das, Payel, Ortwin Gerhard, Flavio de Lorenzi, Emily McNeil, Eugene Churazov, and Lodovico Coccato. "The outer haloes of massive, elliptical galaxies." Proceedings of the International Astronomical Union 5, H15 (November 2009): 92. http://dx.doi.org/10.1017/s1743921310008446.
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The outer haloes of massive elliptical galaxies are dark-matter dominated regions where stellar orbits have longer dynamical timescales than the central regions and therefore better preserve their formation history. Dynamical models out to large radii suffer from a degeneracy between mass and orbital structure, as the outer kinematics are unable to resolve higher moments of the line-of-sight velocity distribution. We mitigate this degeneracy for a sample of quiescent, massive, nearby ellipticals by determining their mass distributions independently using a non-parametric method on X-ray observations of the surrounding hot interstellar medium. We then create dynamical models using photometric and kinematic constraints consisting of integral-eld, long-slit and planetary nebulae (PNe) data extending to ~50 kpc. The rst two galaxies of our sample, NGC 5846 and NGC 1399, were found to have very shallow pro jected light distributions with a power law index of ~1.5 and a dark matter content of 70–80% at 50 kpc. Spherical Jeans models of the data show that, in the outer haloes of both galaxies, the pro jected velocity dispersions are almost inde- pendent of the anisotropy and that the PNe prefer the lower end of the range of mass distributions consistent with the X-ray data. Using the N-body code NMAGIC, we cre- ated axisymmetric models of NGC 5846 using the individual PNe radial velocities in a likelihood method and found them to be more constraining than the binned velocity dispersions. Characterising the orbital structure in terms of spherically averaged proles of the velocity dispersions we nd σψ > σr > σθ.
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Amore, Valentina, Malva I. M. Hernández, Luis M. Carrascal, and Jorge M. Lobo. "Exoskeleton may influence the internal body temperatures of Neotropical dung beetles (Col. Scarabaeinae)." PeerJ 5 (May 18, 2017): e3349. http://dx.doi.org/10.7717/peerj.3349.
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The insect exoskeleton is a multifunctional coat with a continuum of mechanical and structural properties constituting the barrier between electromagnetic waves and the internal body parts. This paper examines the ability of beetle exoskeleton to regulate internal body temperature considering its thermal permeability or isolation to simulated solar irradiance and infrared radiation. Seven Neotropical species of dung beetles (Coleoptera, Scarabaeinae) differing in colour, surface sculptures, size, sexual dimorphism, period of activity, guild category and altitudinal distribution were studied. Specimens were repeatedly subjected to heating trials under simulated solar irradiance and infrared radiation using a halogen neodymium bulb light with a balanced daylight spectrum and a ceramic infrared heat emitter. The volume of exoskeleton and its weight per volume unit were significantly more important for the heating rate at the beginning of the heating process than for the asymptotic maximum temperature reached at the end of the trials: larger beetles with relatively thicker exoskeletons heated more slowly. The source of radiation greatly influences the asymptotic temperature reached, but has a negligible effect in determining the rate of heat gain by beetles: they reached higher temperatures under artificial sunlight than under infrared radiation. Interspecific differences were negligible in the heating rate but had a large magnitude effect on the asymptotic temperature, only detectable under simulated sun irradiance. The fact that sun irradiance is differentially absorbed dorsally and transformed into heat among species opens the possibility that differences in dorsal exoskeleton would facilitate the heat gain under restrictive environmental temperatures below the preferred ones. The findings provided by this study support the important role played by the exoskeleton in the heating process of beetles, a cuticle able to act passively in the thermal control of body temperature without implying energetic costs and metabolic changes.
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Bauer, R., A. Rozanov, C. A. McLinden, L. L. Gordley, W. Lotz, J. M. Russell III, K. A. Walker, et al. "Validation of SCIAMACHY limb NO<sub>2</sub> profiles using solar occultation measurements." Atmospheric Measurement Techniques Discussions 4, no. 4 (July 28, 2011): 4753–800. http://dx.doi.org/10.5194/amtd-4-4753-2011.
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Abstract. The increasing amounts of reactive nitrogen in the stratosphere necessitates accurate global measurements of stratospheric nitrogen dioxide (NO2). Over the past decade, the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on ENVISAT (European Environmental Satellite) has been providing global coverage of stratospheric NO2 every 6 days, which is otherwise difficult to achieve with other systems (e.g. balloon measurements, solar occultation). In this study, the vertical distributions of NO2 retrieved from limb measurements of the scattered solar light from the SCIAMACHY instrument are validated using NO2 products from three different satellite instruments (SAGE II, HALOE and ACE-FTS). The retrieval approach, as well as the sensitivity of the SCIAMACHY NO2 limb data product are discussed, and the photochemical corrections needed to make this validation feasible, as well as the chosen collocation criteria are described. For each instrument, a time period of two years is analyzed with several hundreds of collocation pairs for each year and instrument. The agreement between SCIAMACHY and each instrument is found to be better than 10 % between 22–24 km and 40 km. Additionally, NO2 amounts in three different latitude regions are validated individually, with considerably better agreements in high and middle latitudes compared to tropics. Differences with SAGE II and ACE-FTS below 20 km are consistent with those expected from the diurnal effect.
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Coburn, S., I. Ortega, R. Thalman, B. Blomquist, C. W. Fairall, and R. Volkamer. "Measurements of diurnal variations and eddy covariance (EC) fluxes of glyoxal in the tropical marine boundary layer: description of the Fast LED-CE-DOAS instrument." Atmospheric Measurement Techniques 7, no. 10 (October 28, 2014): 3579–95. http://dx.doi.org/10.5194/amt-7-3579-2014.
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Abstract. Here we present first eddy covariance (EC) measurements of fluxes of glyoxal, the smallest α-dicarbonyl product of hydrocarbon oxidation, and a precursor for secondary organic aerosol (SOA). The unique physical and chemical properties of glyoxal – i.e., high solubility in water (effective Henry's law constant, KH = 4.2 × 105 M atm−1) and short atmospheric lifetime (~2 h at solar noon) – make it a unique indicator species for organic carbon oxidation in the marine atmosphere. Previous reports of elevated glyoxal over oceans remain unexplained by atmospheric models. Here we describe a Fast Light-Emitting Diode Cavity-Enhanced Differential Optical Absorption Spectroscopy (Fast LED-CE-DOAS) instrument to measure diurnal variations and EC fluxes of glyoxal and inform about its unknown sources. The fast in situ sensor is described, and first results are presented from a cruise deployment over the eastern tropical Pacific Ocean (20° N to 10° S; 133 to 85° W) as part of the Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOCs (TORERO) field experiment (January to March 2012). The Fast LED-CE-DOAS is a multispectral sensor that selectively and simultaneously measures glyoxal (CHOCHO), nitrogen dioxide (NO2), oxygen dimers (O4), and water vapor (H2O) with ~2 Hz time resolution (Nyquist frequency ~1 Hz) and a precision of ~40 pptv Hz−0.5 for glyoxal. The instrument is demonstrated to be a "white-noise" sensor suitable for EC flux measurements. Fluxes of glyoxal are calculated, along with fluxes of NO2, H2O, and O4, which are used to aid the interpretation of the glyoxal fluxes. Further, highly sensitive and inherently calibrated glyoxal measurements are obtained from temporal averaging of data (e.g., detection limit smaller than 2.5 pptv in an hour). The campaign average mixing ratio in the Southern Hemisphere (SH) is found to be 43 ± 9 pptv glyoxal, which is higher than the Northern Hemisphere (NH) average of 32 ± 6 pptv (error reflects variability over multiple days). The diurnal variation of glyoxal in the marine boundary layer (MBL) is measured for the first time, and mixing ratios vary by ~8 pptv (NH) and ~12 pptv (SH) over the course of 24 h. Consistently, maxima are observed at sunrise (NH: 35 ± 5 pptv; SH: 47 ± 7 pptv), and minima at dusk (NH: 27 ± 5 pptv; SH: 35 ± 8 pptv). In both hemispheres, the daytime flux was directed from the atmosphere into the ocean, indicating that the ocean is a net sink for glyoxal during the day. After sunset the ocean was a source for glyoxal to the atmosphere (positive flux) in the SH; this primary ocean source was operative throughout the night. In the NH, the nighttime flux was positive only shortly after sunset and negative during most of the night. Positive EC fluxes of soluble glyoxal over oceans indicate the presence of an ocean surface organic microlayer (SML) and locate a glyoxal source within the SML. The origin of most atmospheric glyoxal, and possibly other oxygenated hydrocarbons over tropical oceans, remains unexplained and warrants further investigation.
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Bora, R., B. B. Maini, and A. Chakma. "Flow Visualization Studies of Solution Gas Drive Process in Heavy Oil Reservoirs Using a Glass Micromodel." SPE Reservoir Evaluation & Engineering 3, no. 03 (June 1, 2000): 224–29. http://dx.doi.org/10.2118/64226-pa.
Full textAbstract:
Summary A series of flow visualization experiments was carried out to examine the pore scale behavior of the solution gas drive process in heavy oil reservoirs. The main objective was to testify several speculative theories that had been put forward to explain the anomalous production behavior of heavy oil reservoirs producing under the solution gas drive process. Contrary to previous postulations, the asphaltene constituents did not appear to play a significant role in the nucleation and stabilization of the gas bubbles that evolved during the solution gas drive process. Experimental evidence also suggests that the production of heavy oil is not accompanied by a large population of microbubbles. These observations suggest that the production enhancement in the solution gas process in heavy oil reservoirs may be related to other mechanisms such as viscous coupling effects, sand production, wormhole effects, etc. Introduction Primary production of heavy oil reservoirs operating under the solution gas drive mechanism exhibits an unexpectedly higher primary recovery with a slower pressure decline rate, lower than expected gas oil ratios, and higher oil production rates. These reservoirs which are prolific during the primary production phase have shown very poor response to secondary recovery techniques, such as thermal recovery. Ongoing observations in the fields 1–4 and preliminary observations in laboratories 5–7 strongly suggest that the cold production process of heavy oil reservoirs by the solution gas drive process involves a multitude of effects. A detailed analysis of such unusual production behavior was first provided by Smith.1 He suggested that the solution gas drive in heavy oil reservoirs involves simultaneous flow of oil and gas in the form of microbubbles. Following this, the flow behavior of such gas-oil dispersions has been the subject of several investigators and considerable speculation.2–9 However, the solution gas mechanism in heavy oil reservoirs remains controversial and poorly understood. Background In the solution gas drive process, the main source of energy driving the oil towards the wellbore is the evolution and expansion of the gas bubbles initially dissolved in the oil. The role of the gas bubbles in the oil displacement process has been studied for a long time.10--16 The first visual studies of the behavior of the solution gas process at the microscopic level was performed by Chatenever et al.14 using thin glass bead packings and thin sections of natural sandstone and limestone. With the advent of glass micromodels, flow visualization studies were conducted to examine the microscopic behavior of the solution gas drive process.17–22 All these studies provided a direct observation of pore level events. However, a comprehensive understanding of the pore scale physics in the solution gas drive process has not yet been attained. Moreover, recent observations in the field led to revised thinking of the mechanisms involved in the solution gas drive process in heavy oil reservoirs. The flow of heavy oil under the solution gas drive process appears to be more complex than what is expected from conventional solution gas drive theories. None of the previous studies focused on the behavior of the solution gas process in heavy oil reservoirs. To acquire an improved understanding of the solution gas drive mechanisms, it is necessary to consider the pore scale physics. Most of the questions concerning nucleation, growth, coalescence, and flow of the gas bubbles dispersed in oil can be answered only by direct examination of individual pore scale events. Although it is not possible to visually examine the processes occurring at the pore level in actual reservoir rocks, a very close approximation can perhaps be achieved in a micromodel. Micromodels provide a very convenient means of directly observing the formation, growth, flow, and trapping of gas bubbles. The main objective of this work was to carry out a series of flow visualization experiments, using a high pressure etched glass micromodel, to make a detailed investigation of the effects of asphaltene particles, pressure depletion rates, and sand wettability on the pore level flow mechanisms in the solution gas drive process. To the best of our knowledge, there has been no such systematic investigation of pore scale physics of the solution gas drive process in heavy oil reservoirs. The applications and technical contributions of such a study include the following:an improved understanding of the solution gas drive mechanism in heavy oil reservoirs,planning optimum development strategies for heavy oil reservoirs, andunderstanding of the condition of the reservoir at the end of the primary production phase which is helpful for developing an effective follow-up secondary recovery technique. Micromodel Apparatus The experimental setup is shown schematically in Fig. 1. The heart of the test rig is the high pressure etched glass micromodel. Conceptually, it is simple in design. Two glass plates were held together by overburden pressure inside a windowed pressure vessel. One of the glass plates had a detailed flow pattern chemically etched onto it, the other plate was unetched and had parallel sides. The flow pattern used in this work is displayed in Fig. 2. Here, the black dots represent sand grains while the white area represents the flow channels. The center to center distance between adjoining "sand grains" was 500 µm and the diameter of each dot was 334 µm. The average depth of etched flow channels was about 50 µm. The pore volume within the boundaries of the etched pattern was approximately 75 µL. The etched flow patterns were illuminated with high intensity halogen light bulbs underneath the bottom window of the pressure vessel. The overburden pressure in the pressure vessel was maintained at 600 psi (4.14 MPa) throughout the entire study.
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"Trace element removal from hot gasification flue gases using solid sorbents." Issue 2 8, no. 2 (April 29, 2013): 137–45. http://dx.doi.org/10.30955/gnj.000368.
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Coals contain elements which, although usually found in concentrations lower than 1% (trace
elements), can give rise to environmental or technological problems. After gasification most of
these elements may occur in gas phase in different proportions. In order to avoid the
problems that the presence of trace elements in gas phase can originate during coal
gasification processes, a suitable technology needs to be developed. The systems currently
being studied and developed for gas cleaning in coal gasification, focus on the removal of
sulphur, particulate matter, nitrogen, alkali metals and halogens but not on corrosive or toxic
trace elements. Nevertheless, the reduction of trace elements using solid sorbents in gas
phase at high temperatures appears to be a promising method for combustion systems.
The main objectives of this work were to determine the capacity of different solid sorbents for
retaining arsenic, selenium, cadmium and zinc species in gases from coal gasification
systems at 550 and 750 ºC and to find out how the sorbent characteristics and operational
variables (temperature and gas composition) influence retention. To attain these objectives
the sorption capacity (mg of element per g of sorbent) and the efficiency (percentage of
element retention) were determined. The study was carried out in a laboratory scale reactor,
in which the sorbent was employed as a fixed bed, using synthetic gas mixtures. At the end of
each experiment, the sorbent bed (mixture of sorbent + sand) was finely ground and
dissolved in a microwave oven with HF, HNO3 and H3BO3, and the element in solution was
determined by ICP-MS.
The results are discussed in the light of the data for combustion conditions reported in the
literature, and possible retention mechanisms are proposed. Different amounts of arsenic,
selenium, cadmium, and zinc can be retained in solid sorbents at high temperatures. It was
observed that, in a coal gasification atmosphere, limestone, fly ashes and metallic oxide
mixtures containing spinels, were the best sorbents, though in each case the retention
capacity depended on temperature and atmosphere. Retention capacities between 16-24
mg g-1 were obtained using limestone and fly ashes for arsenic retention. For selenium, the
maximum retention capacities ranging between 50-56 mg g-1 were attained using limestone.
Alumina in a gasification atmosphere containing HCl was the best sorbent for zinc removal
(52 mg g-1). The lowest retention capacities were obtained for cadmium, these being <1 mg g-1
for the different sorbents tested. Retention probably proceeds through different mechanisms,
but in most cases a chemical reaction is involved.
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Jorge, Caroline de Freitas, Sandro Basso Bitencourt, Letícia Cerri Mazza, Marcio Campaner, Juliana Lujan Brunetto, Letícia de Paula Gimenez Billoba, Daniela Micheline Dos Santos, and Aldiéris Alves Pesqueira. "O desafio do restabelecimento de um sorriso antiestético por meio de prótese fixa metal-free." ARCHIVES OF HEALTH INVESTIGATION 8, no. 1 (April 22, 2019). http://dx.doi.org/10.21270/archi.v8i1.3236.
Full textAbstract:
Para alcançar a estética em dentes anteriores deve-se ter conhecimento de diversas técnicas e principalmente fazer a escolha correta dos materiais. As cerâmicas odontológicas estão cada vez mais presentes nas restaurações, visto que possuem ótimas propriedades ópticas e mecânicas. Assim, o objetivo deste estudo foi proporcionar a estética em dentes anteriores com diferentes subtratos através de uma prótese fixa metal-free. Paciente do gênero masculino, 38 anos, procurou atendimento queixando-se da estética do seu sorriso. No exame clínico foi observada uma coroa total metalocerâmica no elemento 21 e facetas de resina composta nos elementos 11,12 e 22, todas com estética insatisfatória. O dente 21 apresentava um núcleo metálico fundido adequado e os dentes 12 e 22 com tratamentos endodônticos. Foi proposta a instalação de pinos de fibra de vidro nos dentes 12 e 22. Além, da confecção de coroas totais metais-free em dissilicato de lítio nos quatro incisivos superiores com o sistema e-max ceram. O resultado final estético e funcional foi aprovado pelo paciente e pelos profissionais envolvidos.Descritores: Estética Dentária; Cerâmica; Reabilitação Bucal.ReferênciasOkida RC, De Moura AP, Franco LM, Salomão FM, Rahal S, Machado LS, Okida DSS. A utilização do DSD (Digital Smile Design) para a otimização da estética dental. Rev Odontol Araçatuba 2017;38(3):9-14.Sabatini C. Color stability behavior of methacrylate-based resin composites polymerized with light-emitting diodes and quartz-tungsten-halogen. Oper Dent. 2015;40(3):71-81.Wang X, Huyang G, Palagummi SV, Liu X, Skrtic D, Beauchamp C et al. High performance dental resin composites withhydrolytically stable monomers. Dent Mater. 2018;34(2):228-37.Yazici AR, Celik C, Dayangaç B, Ozgünaltay G. The effect of curing units and staining solutions on the color stability of resin composites. Oper Dent. 2007; 32(6):616-22.Aguiar EMG, Rodrigues RB, Lopes CCA, Silveira Júnior CD, Soares CJ, Novais VR. Diferentes sistemas cerâmicos na reabilitação oral: relato de caso clínico. Rev Odontol Bras Central. 2016;25(72):31-6.Mazaro JVQ, Zavanelli AC, Pellizzer EP, Verri FR, Falcón-Antennucci RM. Considerações clínicas para a restauração da região anterior com facetas laminadas. Rev Odontol Araçatuba. 2009;30(1):51-4.Vichi A, Louca C, Corciolani G, Ferrari M. Color related to ceramic and zirconia restorations: a review. Dent Mater. 2011;27(1):97-108.Rossato DM, Saade EG, Saad JRC, Porto-Neto ST. Coroas estéticas anteriores em cerâmica metal-free: relato de caso clínico. Rev Sul-Bras Odontol. 2010;7(4):494-98.Lanza MDS, Andreeta MRB, Pegoraro TA, Pegoraro LF, Carvalho RM. Influence of curing protocol and ceramic composition on the degree of conversion of resin cement. J Appl Oral Sci. 2017;25(6):700-7.Soares PFB, Siqueira JM, Carvalho VF, Bicalho AA, Soares CJ. Contenção interdentária empregando fibra de vidro e resina composta: Relato de caso e acompanhamento de 14 anos. Rev Odontol Bras Central. 2016;25(73):80-3.Martinez-Insua A, da Silva L, Rilo B, Santana U. Comparison of the fracture resistances of pulpless teeth restored with a cast post and core or carbon-fiber post with a composite core. J Prosthet Dent. 1998;80(5):527-32.Rocha IJPB, Silva LDR, de Santa Maria SL, Oliveira DP, Porfírio Z. Análise de dois métodos de desinfecção de condutos radiculares após preparo para pinos: proposta de protocolo protético: estudo in vitro. Rev Odontol UNESP. 2017;46(4):189-95.Dede DÖ, Ceylan G, Yilmaz B. Effect of brand and shade of resin cements on the final color of lithium disilicate ceramic. J Prosthet Dent. 2017;117(4):539-44.Lopes Cde C, Rodrigues RB, Silva AL, Simamoto Júnior PC, Soares CJ, Novais VR. Degree of conversion and mechanical properties of resin cements cured through different all-ceramic systems. Braz Dent J. 2015;26(5):484-89.Martins FV, Vasques WF, Fonseca EM. How the variations of the thickness in ceramic restorations of lithium disilicate and the use of different photopolymerizers influence the degree of conversion of the resin cements: a systematic review and meta‐analysis. J Prosthodont. 2019;28(1):e395-403.Turp V, Turkoglu P, Sen D. Influence of monolithic lithium disilicate and zirconia thickness on polymerization efficiency of dual‐cure resin cements. J Esthet Restor Dent. 2018;30(4):360-68.Tavarez RR, Gonçalves LM, Dias AP, Dias AC, Malheiros AS, Silva AC. An harmonic smile resulted from the use of ceramic prosthesis with zirconia structure: a case report. J Int Oral Health. 2014;6(3):90-2.Vaz EC, Vaz MM, de Torres ÉM, de Souza JB, Barata TDJE, Lopes LG. Resin cement: correspondence with try in paste and influence on the immediate final color of veneers. J Prosthodont. 2019;28(1):e74-81.Ladha K, Verma M. Conventional and contemporary luting cements: an overview. J Indian Prosthodont Soc. 2010;10(2):79-88.