Journal articles: 'Sulfur dioxide Spectra'

1

Bai, Xiulin, Qinlin Xiao, Lei Zhou, Yu Tang, and Yong He. "Detection of Sulfite Dioxide Residue on the Surface of Fresh-Cut Potato Slices Using Near-Infrared Hyperspectral Imaging System and Portable Near-Infrared Spectrometer." Molecules 25, no. 7 (April 3, 2020): 1651. http://dx.doi.org/10.3390/molecules25071651.

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Sodium pyrosulfite is a browning inhibitor used for the storage of fresh-cut potato slices. Excessive use of sodium pyrosulfite can lead to sulfur dioxide residue, which is harmful for the human body. The sulfur dioxide residue on the surface of fresh-cut potato slices immersed in different concentrations of sodium pyrosulfite solution was classified by near-infrared hyperspectral imaging (NIR-HSI) system and portable near-infrared (NIR) spectrometer. Principal component analysis was used to analyze the object-wise spectra, and support vector machine (SVM) model was established. The classification accuracy of calibration set and prediction set were 98.75% and 95%, respectively. Savitzky–Golay algorithm was used to recognize the important wavelengths, and SVM model was established based on the recognized important wavelengths. The final classification accuracy was slightly less than that based on the full spectra. In addition, the pixel-wise spectra extracted from NIR-HSI system could realize the visualization of different samples, and intuitively reflect the differences among the samples. The results showed that it was feasible to classify the sulfur dioxide residue on the surface of fresh-cut potato slices immersed in different concentration of sodium pyrosulfite solution by NIR spectra. It provided an alternative method for the detection of sulfur dioxide residue on the surface of fresh-cut potato slices.

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Anderson, A. "Infrared and Raman spectra of crystalline sulfur dioxide." Journal of Chemical Physics 67, no. 9 (1999): 4300. http://dx.doi.org/10.1063/1.435371.

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Rongtong, Bumrungrat, Thongchai Suwonsichon, Pitiporn Ritthiruangdej, and Sumaporn Kasemsumran. "Determination of sulfur dioxide content in osmotically dehydrated papaya and its classification by near infrared spectroscopy." Journal of Near Infrared Spectroscopy 26, no. 6 (October 25, 2018): 359–68. http://dx.doi.org/10.1177/0967033518808054.

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Sulfur dioxide (SO2) is used as a preservative in osmotically dehydrated papaya to improve product quality and extend shelf-life. The potential of near infrared spectroscopy, as a rapid method, was investigated to determine sulfur dioxide in osmotically dehydrated papaya. Commercial and laboratory osmotically dehydrated papaya samples were selected to determine the sulfur dioxide content using the Monier–Williams method. From the total of 350 samples, subsets were selected randomly for the calibration set (n=250) and validation set (n = 100). Near infrared spectra in the region 800–2400 nm were measured on the samples of osmotically dehydrated papaya. Quantitative analyses of sulfur dioxide in the osmotically dehydrated papaya and their qualitative analyses were carried out using multivariate analysis. Before developing models, a second derivative spectral pretreatment was applied to the original spectral data. Subsequently, two wavelength interval selection methods, namely moving window partial least squares regression (MWPLSR) and searching combination moving window partial least squares (SCMWPLS), were applied to determine the suitable input wavelength variables. For quantitative analysis, three linear models (partial least squares regression, MWPLSR and SCMWPLS) and a non-linear artificial neural network model were applied to develop predictive models. The results showed that the artificial neural network model produced the best performance, with correlation coefficient (R) and root mean square error of prediction values of 0.937 and 114.53 mg SO2 kg−1, respectively. Qualitative models were developed using partial least squares-discriminant analysis and soft independent modeling of class analogy (SIMCA) for the optimized combination of informative regions of the near infrared spectra to classify osmotically dehydrated papaya into three groups based on sulfur dioxide. The SIMCA in combination with SCMWPLS model had the highest correct classification rate (96%). The study demonstrated that near infrared spectroscopy combined with SCMWPLS is a powerful procedure for both quantitative and qualitative analyses of osmotically dehydrated papaya. Therefore, it was demonstrated that near infrared spectroscopy could be effective tools for food quality and safety evaluation in food industry.

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Smirnova, O. V., A. G. Grebenyuk, and V. V. Lobanov. "A quantum chemical study on the effect of titanium dioxide modification with non-metals on its spectral characteristics." Himia, Fizika ta Tehnologia Poverhni 11, no. 4 (December 30, 2020): 539–46. http://dx.doi.org/10.15407/hftp11.04.539.

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The experimental results obtained in the study on the possibility of sensitizing titanium dioxide (polymorphic anatase phase) to the visible region of the spectrum by doping and co-doping with impurities of non-metals in order to create effective photocatalysts for the decomposition of organic compounds have been analyzed. The presence of impurity atoms appears to result in a change in the electronic structure of the titanium dioxide matrix, in the appearance of “impurity bands” and in the narrowing of the energy gap of titanium dioxide. Such a modification is accompanied by an extension of the spectral range of sensitivity of photoactive solids to the long-wavelength region of the spectrum and, therefore, can be used to improve the catalytic properties of these materials. Spectral manifestations of carbon impurities in titanium dioxide in the form of carbide and carbonate, as well as sulfur in the forms of sulfite, sulfide, and sulfate, have been studied by the density functional theory method. A Ti14H22O39 cluster model was chosen for the titanium dioxide matrix. The calculations were carried out in the framework of the cluster approximation, using functional B3LYP and basis set 6-31G (d, p). Comparison of the results of quantum chemical calculations with the available experimental data shows that the impurity sulfur and carbon atoms in titanium dioxide, which are in different coordination states and different oxidation states, appear in different spectral ranges. This circumstance makes it possible to elucidate the structure of the samples based on the experimental spectra. A change in the coordination and oxidation states of impurity atoms leads to spectral shifts and splitting of peaks, which can reach 1.5 eV (XPS). The presence of admixtures of non-metals leads to a change in color (deepening in the case of sulfide or carbide) of the samples, appearing in the corresponding UV spectra.

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Coates, J., and K. L. DeVries. "Effects of stress and sulfur dioxide on Spectra ®." Polymer 41, no. 12 (June 2000): 4661–69. http://dx.doi.org/10.1016/s0032-3861(99)00673-4.

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Carlson, R. W., W. D. Smythe, D. L. Matson, R. Lopes-Gautier, J. Hui, M. Segura, A. C. Ocampo, et al. "Surface Composition of the Galilean Satellites from Galileo Near-Infrared Mapping Spectroscopy." Highlights of Astronomy 11, no. 2 (1998): 1078–81. http://dx.doi.org/10.1017/s1539299600019638.

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AbstractThe Galileo Near Infrared Mapping Spectrometer (NIMS) is currently obtaining spectral maps of Jupiter’s moons to determine the composition and spatial distribution of minerals on the satellite surfaces. Sulfur dioxide, as a frost or ice, covers much of Io’s surface, except in hot volcanic areas. A weak spectral feature at 3.15 μm suggests the presence of an OH containing surface compound (hydroxide, hydrate, or water) and a broad absorption above 1 μm is reasonably attributed to iron-containing minerals, such as feldspars and pyrite. Water is the dominant molecule covering Europa’s surface, occurring as ice but also as a hydrate. The trailing side shows high concentrations of these hydrous minerals, whose identifications are not yet established. Ganymede’s surface exhibits water absorption bands, largely due to ice but hydrates are also present. A dark component is present, but with a smaller proportion compared to Callisto. Some of the non-ice features seen on Ganymede are similar to those found in Callisto’s spectra (see below). Among the icy Galilean satellites, Callisto shows the least amount of water ice, covering about 10% of the surface in patchy concentrations. Most of the surface is covered with unidentified (as yet) dark minerals. The exposed ice is often associated with impact craters, implying that the darker material exists as a blanket over more pure ice. Non-ice spectral features at 3.88, 4.03, 4.25, and 4.57 μm are present in Callisto’s spectra (and some of these appear in Ganymede’s spectra), each with different spatial distributions. Laboratory spectra suggest that the 4.25-μm feature is due to carbon dioxide which is trapped in the surface grains. The band at 4.03 μm may be due to sulfur dioxide, which probably originated from Io. Molecules containing CN, SH, SiH, and perhaps deuterated constituents are candidates for the other features, some of which could be derived from shock-heated and modified material from impacts, perhaps of carbonaceous composition. There is evidence for the presence of hydrated minerals on Callisto, based on water band shifts and shapes.

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Lovas, F. J. "Microwave Spectra of Molecules of Astrophysical Interest. XXII. Sulfur Dioxide (SO2)." Journal of Physical and Chemical Reference Data 14, no. 2 (April 1985): 395–488. http://dx.doi.org/10.1063/1.555729.

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Hayashi, Soichi, Motohisa Oobatake, Tatsuo Ooi, and Katsunosuke Machida. "Molecular Dynamics Using Internal Coordinates. I. Infrared Spectra of Sulfur Dioxide." Bulletin of the Chemical Society of Japan 58, no. 4 (April 1985): 1105–8. http://dx.doi.org/10.1246/bcsj.58.1105.

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Othman, Fatin Fatini, Banjuraizah Johar, Shing Fhan Khor, Suffi Irni Alias, Nik Akmar Rejab, and Syed Nuzul Fadzli Adam. "Characterisation Of FGD Sludge From One of Glass Industrial in Malaysia and Their Potential as Ceramic Mould." Journal of Physics: Conference Series 2129, no. 1 (December 1, 2021): 012093. http://dx.doi.org/10.1088/1742-6596/2129/1/012093.

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Abstract Flue Gas Desulfurization (FGD) is a waste incineration process used to eliminate sulfur dioxide (SO2) from flue gas power plants. Limestone/gypsum was injected into the plant to trap sulfur dioxide and change their chemical composition from calcium carbonate to calcium sulfate dehydrate, known as FGD sludge wet scrubber. Nowadays, it is necessary to overcome the environmental pollution caused by the massive production of FGD sludge waste through recycling. In this research, FGD sludge was characterised to reveal its chemical composition, crystalline phase, and FTIR spectra characteristics. FGD sludge recorded a moderate alkaline with a pH of 8.24. Based on the XRD result, FGD sludge was mainly composed of gypsum (CaSO4•2H2O) and anhydrite (CaSO4). XRF analysis also shows that FGD sludge was mainly composed of calcium oxide, sulfur trioxide, silica, and potassium oxide.

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Ye, Yanpeng, Enlai Wan, Zhongmou Sun, Xinyang Zhang, Zhirong Zhang, and Yuzhu Liu. "Online detection and source tracing of crop straw burning." Journal of Laser Applications 34, no. 4 (November 2022): 042049. http://dx.doi.org/10.2351/7.0000866.

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The carbon dioxide, sulfur dioxide, and metal ions produced by straw burning can severely pollute the atmosphere; thus, online detection and traceability for straw burning is very important. However, to our best knowledge, there is no comprehensive system that can satisfy online detection, classification, and traceability due to the challenging online detection and traceability of straw burning. In this paper, a new system based on laser-induced breakdown spectroscopy (LIBS) and machine learning is developed, and this developed system is employed for the first time in online detection and traceability of straw combustion. Four different types of straw are selected and the straw burning smoke is monitored online using this developed system. The analysis of straw smoke spectra shows that there are Fe, Mn, and Ba heavy metal spectra in the smoke spectra. By comparing the smoke spectra of different types of straw, the characteristic spectral lines with large differences are selected and dimensionality reduction is performed by linear discriminant analysis algorithm. Then, combined with random forest to achieve classification, the final smoke recognition accuracy reaches 87.0%. Straw ash is then used as a reference analysis and the same operation is performed on it. Mn, Ba, and Li heavy metal spectral lines are found in the spectra of ash, and the final recognition accuracy is 92.6%. The innovative and developed system based on LIBS and machine learning is fast, online, and in situ and has far-reaching application prospects in the environment.

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Wong, Ming Wah, and Kenneth B. Wiberg. "Structures, bonding, and absorption spectra of amine-sulfur dioxide charge-transfer complexes." Journal of the American Chemical Society 114, no. 19 (September 1992): 7527–35. http://dx.doi.org/10.1021/ja00045a028.

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12

Gerding, H., and J. W. Ypenburg. "Some remarks on the vibrational spectra of liquid and solid sulfur dioxide." Recueil des Travaux Chimiques des Pays-Bas 86, no. 4 (September 2, 2010): 458–62. http://dx.doi.org/10.1002/recl.19670860416.

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Bellotti, Amadeo, and Paul G. Steffes. "The millimeter-wavelength sulfur dioxide absorption spectra measured under simulated Venus conditions." Icarus 254 (July 2015): 24–33. http://dx.doi.org/10.1016/j.icarus.2015.03.028.

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14

Li, San, and Ying-Sing Li. "FT-IR spectra of matrix isolated complexes between some alkanethiols and sulfur dioxide." Journal of Molecular Structure 248, no. 1-2 (August 1991): 79–88. http://dx.doi.org/10.1016/0022-2860(91)85004-m.

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Keussen, Ch, N. Heineking, and H. Dreizler. "A Microwave Fourier Transform Spectrometer in the Frequency Band From 26 to 40 GHz." Zeitschrift für Naturforschung A 44, no. 3 (March 1, 1989): 215–21. http://dx.doi.org/10.1515/zna-1989-0308.

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We report the design and performance of a microwave Fourier transform spectrometer in the frequency region between 26 and 40 GHz for the investigation of rotational spectra. The performance is illustrated by rotational transitions of allene and allene-d4 molecules with a very small dipole moment in vibrational excited states. The sensivity and Doppler limited linewidth is demonstrated by measurements of transitions of isotopomers of carbonyl sulfide and sulfur dioxide.

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Li, S., H. Kurtz, P. Korambath, and Y. S. Li. "Infrared spectra, photochemistry, and ab initio calculations of matrix isolated methanethiol/sulfur dioxide complex." Journal of Molecular Structure 550-551 (September 2000): 235–44. http://dx.doi.org/10.1016/s0022-2860(00)00520-2.

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Song, Bin, Hirohide Nakamatsu, Akio Shigemi, Takeshi Mukoyama, and Kazuo Taniguchi. "Calculations of x-ray emission spectra for sulfur dioxide by the DV-Xα method." X-Ray Spectrometry 28, no. 2 (March 1999): 94–98. http://dx.doi.org/10.1002/(sici)1097-4539(199903/04)28:2<94::aid-xrs315>3.0.co;2-a.

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Arab, Hamed, Gian Luca Chiarello, Elena Selli, Giacomo Bomboi, Alberto Calloni, Gianlorenzo Bussetti, Guglielmo Albani, Massimiliano Bestetti, and Silvia Franz. "Ni-Doped Titanium Dioxide Films Obtained by Plasma Electrolytic Oxidation in Refrigerated Electrolytes." Surfaces 3, no. 2 (April 17, 2020): 168–81. http://dx.doi.org/10.3390/surfaces3020013.

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Porous crystalline Ni-doped TiO2 films were produced using DC plasma electrolytic oxidation in refrigerated H2SO4 aqueous solutions containing NiSO4. The crystalline phase structure consisted of a mixture of anatase and rutile, ranging from ~30 to ~80 wt % rutile. The oxide films obtained at low NiSO4 concentration showed the highest photocurrent values under monochromatic irradiation in the UV-vis range, outperforming pure TiO2. By increasing NiSO4 concentration above a threshold value, the photoelectrochemical activity of the films decreased below that of undoped TiO2. Similar results were obtained using cyclic voltammetry upon polychromatic UV-vis irradiation. Glow discharge optical emission spectrometry (GD-OES) analysis evidenced a sulfur signal peaking at the TiO2/Ti interface. XPS spectra revealed that oxidized Ni2+, S4+ and S6+ ions were included in the oxide films. In agreement with photocurrent measurements, photoluminescence (PL) spectra confirmed that less intense PL emission, i.e., a lower electron-hole recombination rate, was observed for Ni-doped samples, though overdoping was detrimental.

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Schriver-Mazzuoli, L., A. Schriver, and H. Chaabouni. "Photo-oxidation of SO2 and of SO2 trapped in amorphous water ice studied by IR spectroscopy. Implications for Jupiter's satellite Europa." Canadian Journal of Physics 81, no. 1-2 (January 1, 2003): 301–9. http://dx.doi.org/10.1139/p03-039.

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Fourier Transform Infrared Spectroscopy (FTIR), is used to characterize thin films of sulfur dioxide trapped in excess of amorphous water ice and to study the photo-oxidation of pure solid SO2 or of SO2 diluted in water ice. These laboratory experiments were undertaken in an attempt to find information on the formation of hydrated sulfuric acid detected on Europa's surface. Vibrational spectra at 30 K of mixed films containing SO2 with an excess of water depend on the deposition conditions. A metastable (SO2)m(H2O)n phase and a solid solution of SO2 in water ice have been evidenced. Irradiation at 266 nm of mixed films SO2/O3/H2O produces sulfur trioxide and hydrogen peroxide without traces of sulfuric acid. Irradiation of films of pure SO2, under 200 nm, leads to sulfur trioxide and to ozone. When SO2 is diluted in amorphous water ice, new weak bands that appear after irradiation suggest the formation of sulfuric acid. PACS No.: 82.50Hp

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Thornton, D. C., A. R. Bandy, and J. G. Hudson. "Fast sulfur dioxide measurements correlated with cloud concentration nuclei spectra in the marine boundary layer." Atmospheric Chemistry and Physics Discussions 11, no. 5 (May 17, 2011): 14903–32. http://dx.doi.org/10.5194/acpd-11-14903-2011.

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Abstract. During the Rain in (shallow) Cumulus over the Ocean (RICO) project simultaneous measurements of high rate sulfur dioxide (SO2) measurements and cloud condensation nuclei (CCN) spectra were made for the first time. During research flight 14 (14 January 2005) the convective boundary layer was impacted by precipitation and ship plumes in midday but not in the late afternoon. Accumulation mode aerosols (0.14 to 0.2 μm diameter) were a factor of two greater in the latter period while CCN were 30 % to 65 % greater for aerosols that activate at supersaturations >0.1 %. Linear correlations of SO2 and CCN were found for SO2 concentrations ranging from 20 to 600 parts-per-trillion (pptv). The greatest sensitivities were for SO2 and CCN that activate at supersaturations >0.1 % for both clean and polluted air. In a region affected by a cold pool event SO2 was only linearly correlated with CCN at >0.2 % S.

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Thornton, D. C., A. R. Bandy, and J. G. Hudson. "Fast sulfur dioxide measurements correlated with cloud condensation nuclei spectra in the marine boundary layer." Atmospheric Chemistry and Physics 11, no. 22 (November 21, 2011): 11511–19. http://dx.doi.org/10.5194/acp-11-11511-2011.

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Abstract. During the Rain in (shallow) Cumulus over the Ocean (RICO) project simultaneous high rate sulfur dioxide (SO2) measurements and cloud condensation nuclei (CCN) spectra were made for the first time. For research flight 14 (14 January 2005) the convective boundary layer was impacted by precipitation and ship plumes for much of the midday period but not in the late afternoon. Number densities of accumulation mode aerosols (0.14 to 0.2 μm diameter) were a factor of two greater in the later period while CCN were 35% to 80% greater for aerosols that activate at supersaturations >0.1%. Linear correlations of SO2 and CCN were found for SO2 concentrations ranging from 20 to 600 parts-per-trillion (pptv). The greatest sensitivities were for SO2 and CCN that activate at supersaturations >0.1% for both clean and polluted air. In a region unaffected by pollution SO2 was linearly correlated only with CCN at >0.2% supersaturation. These correlations imply that the smallest CCN may be activated by SO2 through heterogeneous conversion. Evidence for entrainment of CCN from the cloud layer into the CBL was found.

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LI, S., and Y. S. LI. "ChemInform Abstract: FT-IR Spectra of Matrix Isolated Complexes Between Some Alkanethiols and Sulfur Dioxide." ChemInform 22, no. 43 (August 22, 2010): no. http://dx.doi.org/10.1002/chin.199143037.

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Bashir, Errum, Khawar Anwar, Muhammad Usman Anjum, and Wajid Rehman. "Effect of toxic gases on human erythrocytes: Spectrophotometric analysis." Professional Medical Journal 28, no. 10 (September 30, 2021): 1525–30. http://dx.doi.org/10.29309/tpmj/2021.28.10.6354.

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Objective: This study was carried out to analyze the influence of various toxic gases on human erythrocytes. Study Design: Experimental study. Setting: Department of Chemistry, Hazara University, Mansehra. Period: January 2017 to June 2017. Material & Methods: Erythrocytes were isolated and prepared by the standard method from blood samples. The standard absorption spectra were recorded in the range of 200-800nm using double‐beam UV‐visible spectrophotometer. Gases were prepared in laboratory as per given protocol. Erythrocyte samples were treated with prepared gases. Absorbance of the samples was recorded. The spectrum of these treated samples was compared with the standard spectra of erythrocytes to check for any changes that might have occurred. Results: It was observed that erythrocytes exhibiteded altered behavior with each gas which was confirmed by shift in peaks in UV/Visible spectra. Absorption maxima were shifted from higher to lower wavelengths and this shift was more pronounced in case of Chlorine, Carbon Monoxide and Carbon Dioxide as compared to that observed in case of Hydrogen Sulfide, Sulfur dioxide, and Nitrogen Dioxide. Conclusion: This study showed that erythrocytes exhibit different behavior with different gases as evident by the shift of peaks in UV/Visible spectra. The absorption maxima were shifted towards lower wavelengths suggesting that these gases do exert an effect on human erythrocytes. The lipid site of erythrocytes, being sensitive for absorbing various atmospheric gases, caused deformation of original erythrocyte structure and altered their activity. This type of interaction of red blood cells with such external species, particularly the donor-acceptor case, caused damage to erythrocytes and in turn, decreased their number.

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Docherty, Suzanne, Raminta Zmuidinaite, James Coulson, Martin Besser, and Ray Iles. "The Diagnosis of Sulfated Hemoglobin (SulfHb) Secondary to Sulfur Dioxide Poisoning Using Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry (MALDI-ToF MS)—A Novel Approach to an Unusual Clinical Problem." Diagnostics 10, no. 2 (February 10, 2020): 94. http://dx.doi.org/10.3390/diagnostics10020094.

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Sulfhemoglobinemia is a rare entity caused by irreversible sulfation of the heme moiety in haemoglobin to form sulfated haemoglobin (SulfHb) and has been caused by H2S arising from certain metabolites of drugs and bacterial infection. Clinical presentation is similar to that of methemoglobin (MetHb). Furthermore, it is often difficult to distinguish between the diagnosis of SulfHb from MetHb in arterial blood gas analysers due to the broad overlap in the optical density (OD) absorption spectra—that of SulfHb swamping the more distinct OD absorption shift seen with MetHb. The presence of SulfHb was suspected in a 73-year-old lady with low oxygen saturation (SaO2 ~75%), central cyanosis, and normal arterial oxygen partial pressure (pO2 ~12 kPa). Repeated arterial blood gas analysis on different systems returned error messages for MetHb quantification. There was an improvement in oxygen saturation and cyanosis after an exchange transfusion. A full OD spectrophotometry (500–700 nm) of the patient’s whole blood was suggestive of the presence of SulfHb, with a minor peak absorption at 620 nm. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF MS) was undertaken on whole blood samples from the patient pre- and post-transfusion, alongside normal controls. These demonstrated the presence of SulfHb in the patient’s blood, identifying sulfur, sulfur monoxide, and sulfur dioxide bound to the heme moiety. This gave vital identification as to the cause of Hb sulfation, which was distinct from that previously reported. Levels fell after the exchange transfusion and were completely eradicated after the correct source, an Epsom Salts constipation tonic, was identified. MALDI-ToF mass spectrometry is a new, rapid, specific, and sensitive diagnostic test for rare hematological syndromes such as SulfHb. In addition, it can identify the specific compounds bound to heme. Here, we provide useful diagnostic evidence as to the source of SulfHb, which was via SO2 rather than the previously described H2S.

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Margulès, Laurent, Roman A. Motiyenko, and Jean Demaison. "Millimeterwave and submillimeterwave spectra of sulfur dioxide 32S16O18O and 32S18O2, centrifugal distortion analysis and equilibrium structure." Journal of Quantitative Spectroscopy and Radiative Transfer 253 (September 2020): 107153. http://dx.doi.org/10.1016/j.jqsrt.2020.107153.

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Andrews, Lester, Robert Withnall, and Rodney D. Hunt. "Infrared spectra of the ozone...hydrogen fluoride and sulfur dioxide...hydrogen fluoride complexes in solid argon." Journal of Physical Chemistry 92, no. 1 (January 1988): 78–81. http://dx.doi.org/10.1021/j100312a019.

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Baskin, J. S., F. Al-Adel, and A. Hamdan. "Unexpectedly rich vibronic structure in supersonic jet spectra of sulfur dioxide between 360 and 308 nm." Chemical Physics 200, no. 1-2 (November 1995): 181–99. http://dx.doi.org/10.1016/0301-0104(95)00235-g.

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Faguy, Peter W., William N. Richmond, Richard S. Jackson, Stephen C. Weibel, Gail Ball, and Joe H. Payer. "Real-Time Polarization Modulation in Situ Infrared Spectroscopy Applied to the Study of Atmospheric Corrosion." Applied Spectroscopy 52, no. 4 (April 1998): 557–64. http://dx.doi.org/10.1366/0003702981943879.

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A new methodology for the real-time in situ monitoring of atmospheric corrosion processes is presented. The mid-infrared spectra of surface films formed on polished copper substrates exposed to humid air containing sub-ppm levels of sulfur dioxide, nitric oxide, and hydrogen chloride were obtained by using a novel surface-sensitive infrared technique: real-time polarization modulation grazing angle reflection-absorption spectroscopy. The new methodology demonstrated improved signal-to-noise ratios, by a factor of 2.5, as compared to conventional Fourier transform infrared reflection absorption spectroscopy. Molecular spectroscopic data for water- and hydroxyl-containing species present at the metal surface were obtained with no interference from water vapor. Over the spectral region 4000–800 cm−1, bands were identified and assigned to nitro and nitrito adsorbates, to sulfite ions, and to bound water on the copper surface. Analysis of the time evolution and the profile composition of these bands is possible because of the sensitivity of this new optical sampling technique.

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Mellqvist, J., A. Rosén, and H. Axelsson. "Temperature dependence of the absorption spectra of nitrogen oxide, nitrogen dioxide and sulfur dioxide in the application of differential optical absorption spectroscopy." Analyst 117, no. 3 (1992): 417–18. http://dx.doi.org/10.1039/an9921700417.

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Emelyanova, V. S., K. A. Zhubanov, T. V. Shakieva, and G. A. Yuldasheva. "The kinetics and mechanism of the sulfur dioxide oxidation by the oxygen in the presence of the cobalt and nickel complexes, fixed on polymer matrix." Eurasian Chemico-Technological Journal 1, no. 1 (April 14, 2016): 65. http://dx.doi.org/10.18321/ectj348.

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Catalytic sulphur dioxide oxidation by oxygen on the cobalt and nickel complexes fixed on polyetheleneamine was investigated. On the base of kinetics study it was established that SO2 and oxygen interact in inner sphere mechanism. UV-spectra and quantum-chemical calculations are presented, and on the base of them the ways of oxygen activation are discussed.

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Gao, Qiang, Wubin Weng, Bo Li, Marcus Aldén, and Zhongshan Li. "Gas Temperature Measurement Using Differential Optical Absorption Spectroscopy (DOAS)." Applied Spectroscopy 72, no. 7 (June 18, 2018): 1014–20. http://dx.doi.org/10.1177/0003702818760864.

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A nonintrusive method for flow gas temperature measurement using differential optical absorption spectroscopy (DOAS) was demonstrated. A temperature-dependent spectra (TDS) originated from the DOAS spectra of sulfur dioxide (SO2) in the wavelength range of 276–310 nm was introduced, and the relationship between the TDS and the temperature was built through experimental calibration process. This relationship is found to be independent of SO2 concentration and can be used for temperature measurements. The experimental results indicated that the precision of the TDS method is < ± 0.3% for SO2 concentrations higher than 150 ppm with the optical path length of 170 mm. For lower concentrations, the precision is estimated to be ± 0.4% at 1 ppm. The relative deviation between the temperature measured by the TDS method and that measured by a thermocouple is within 3% in the temperature range of 298–750 K, and the TDS method has a quicker response to the fast-changing temperature than the thermocouple.

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Xie, Daiqian, Guobin Ma, and Hua Guo. "Quantum calculations of highly excited vibrational spectrum of sulfur dioxide. III. Emission spectra from the C̃ 1B2 state." Journal of Chemical Physics 111, no. 17 (November 1999): 7782–88. http://dx.doi.org/10.1063/1.480113.

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Baer, Marcel, Christopher J. Mundy, Tsun-Mei Chang, Fu-Ming Tao, and Liem X. Dang. "Interpreting Vibrational Sum-Frequency Spectra of Sulfur Dioxide at the Air/Water Interface: A Comprehensive Molecular Dynamics Study." Journal of Physical Chemistry B 114, no. 21 (June 3, 2010): 7245–49. http://dx.doi.org/10.1021/jp100310s.

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Khanna, R. K., Guizhi Zhao, M. J. Ospina, and J. C. Pearl. "Crystalline sulfur dioxide: Crystal field splittings, absolute band intensities, and complex refractive indices derived from infra-red spectra." Spectrochimica Acta Part A: Molecular Spectroscopy 44, no. 6 (January 1988): 581–86. http://dx.doi.org/10.1016/0584-8539(88)80111-9.

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Berges, Peer, and Günter Klar. "Elementorganische Verbindungen mit o-Phenylenresten, XV [1]. Hexamethoxy-tetrachalcogena-tetrahydropentacene / Organometallic Compounds with o-Phenylene Substituents, Part XV [1]. Hexamethoxy-tetrachaleogena-tetrahydropentacenes." Zeitschrift für Naturforschung B 43, no. 5 (May 1, 1988): 599–604. http://dx.doi.org/10.1515/znb-1988-0518.

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The title compounds 4 and 5 were prepared by reaction of 1,4-dimethoxy-2,5-bis(3,4-dimethoxyphenylthio) benzene (8) with sulfur dichloride and selenium dioxide, resp., and characterized by 1H NMR and MS spectra. An X-ray analysis of 4 shows the compound to have a chair form, i.e. each of its two thianthrene units are folded at their SS axes in such a way that the two peripheral rings are found at different sites of the central ring plane (angles of fold 130.5°). The methoxy groups of the peripheral rings are coplanar, those of the central ring perpendicular to the corresponding ring planes. Bond distances and angles of 4 are in the normal range (CS 177.5 pm, CSC 100.2°).

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Zhao, Fei, Chunyu Wang, Xianjing Liu, Qingyue Luo, and Ling Zhu. "Purification of fuel ethanol engine exhaust with platinum-loaded Ce0.5Zr0.5O2 catalyst." Nanomaterials and Nanotechnology 9 (January 1, 2019): 184798041988667. http://dx.doi.org/10.1177/1847980419886673.

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This work aimed at exploring a new kind of purification catalysts for fuel ethanol engine exhaust. Platinum loaded on Ce0.5Zr0.5O2 was prepared by impregnation method and characterized by X-ray diffraction, Brunner–Emmet–Teller measurements (BET), temperature-programmed reduction of hydrogen, scanning electron microscope, and X-ray photoelectron spectra. The three-way catalyst platinum/ceria–zirconia/fw is prepared with the paste ball mill coating technique. And the catalytic performance is evaluated under simulated fuel ethanol engine exhaust gas condition. The catalysts not only show excellent low-temperature performances and several-way catalytic activities for carbon monoxide, hydrocarbons, nitrogen oxides, and acetaldehyde but also have better high-temperature resistance. The addition of sulfur dioxide to feedstream degrades the performances of the catalysts.

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Dai, Z., L. K. Tseng, and G. M. Faeth. "Structure of Round, Fully Developed, Buoyant Turbulent Plumes." Journal of Heat Transfer 116, no. 2 (May 1, 1994): 409–17. http://dx.doi.org/10.1115/1.2911413.

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An experimental study of the structure of round buoyant turbulent plumes was carried out, emphasizing conditions in the fully developed (self-preserving) portion of the flow. Plume conditions were simulated using dense gas sources (carbon) dioxide and sulfur hexafluoride) in a still air environment. Mean and fluctuating mixture fraction properties were measured using single-and two-point laser-induced iodine fluorescence. The present measurements extended farther from the source (up to 151 source diameters) than most earlier measurements (up to 62 source diameters) and indicated that self-preserving turbulent plumes are narrower, with larger mean and fluctuating mixture fractions (when appropriately scaled) near the axis, than previously thought. Other mixture fraction measurements reported include probability density functions, temporal power spectra, radial spatial correlations and temporal and spatial integral scales.

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Rickly, Pamela S., Lu Xu, John D. Crounse, Paul O. Wennberg, and Andrew W. Rollins. "Improvements to a laser-induced fluorescence instrument for measuring SO2 – impact on accuracy and precision." Atmospheric Measurement Techniques 14, no. 3 (March 26, 2021): 2429–39. http://dx.doi.org/10.5194/amt-14-2429-2021.

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Abstract. This work describes key improvements made to the in situ laser-induced fluorescence instrument for measuring sulfur dioxide (SO2) that was originally described by Rollins et al. (2016). Here, we report measurements of the SO2 fluorescence emission spectrum. These measurements allow for the determination of the most appropriate bandpass filters to optimize the fluorescence signal, while reducing the instrumental background. Because many aromatic species fluoresce in the same spectral region as SO2, fluorescence spectra were also measured for naphthalene and anisole to determine if ambient SO2 measurements could be biased in the presence of such species. Improvement in the laser system resulted in better tunability, and a significant reduction in the 216.9 nm laser linewidth. This increases the online/offline signal ratio which, in turn, improves the precision and specificity of the measurement. The effects of these improvements on the instrumental sensitivity were determined by analyzing the signal and background of the instrument, using varying optical bandpass filter ranges and cell pressures and calculating the resulting limit of detection. As a result, we report an improvement to the instrumental sensitivity by as much as 50 %.

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Krupa, Justyna, Maria Wierzejewska, and Jan Lundell. "Structure and IR Spectroscopic Properties of HNCO Complexes with SO2 Isolated in Solid Argon." Molecules 26, no. 21 (October 25, 2021): 6441. http://dx.doi.org/10.3390/molecules26216441.

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FTIR spectroscopy was combined with the matrix isolation technique and quantum chemical calculations with the aim of studying complexes of isocyanic acid with sulfur dioxide. The structures of the HNCO⋯SO2 complexes of 1:1, 1:2 and 2:1 stoichiometry were optimized at the MP2, B3LYPD3, B2PLYPD3 levels of theory with the 6-311++G(3df,3pd) basis set. Five stable 1:1 HNCO⋯SO2 complexes were found. Three of them contain a weak N-H⋯O hydrogen bond, whereas two other structures are stabilized by van der Waals interactions. The analysis of the HNCO/SO2/Ar spectra after deposition indicates that mostly the 1:1 hydrogen-bonded complexes are present in argon matrices, with a small amount of the van der Waals structures. Upon annealing, complexes of the 1:2 stoichiometry were detected, as well.

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Stejskalová, Květoslava, Zdeněk Bastl, and Karel Mocek. "Kinetics of the Reaction Between Solid Active Sodium Carbonate of the Second Generation and the Gaseous Sulfur Dioxide." Collection of Czechoslovak Chemical Communications 61, no. 8 (1996): 1141–57. http://dx.doi.org/10.1135/cccc19961141.

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The results are presented of a detailed experimental kinetic study of the heterogeneous reaction between gaseous sulfur dioxide and the solid active sodium carbonate of the second generation which has been prepared by a controlled thermal dehydration of higher hydrates of the sodium carbonate. The measurements have been carried out in an all-glass kinetic apparatus with an integral fixed-bed reactor. The reaction course was studied in dependence on genesis and nature of the active sodium carbonate, on temperature and on composition of the gas phase. The reaction rate is significantly affected by presence of the water vapour which acts as a gaseous catalyst. Experimental data have been treated by using the model proposed by Erdos (Collect. Czech. Chem. Commun. 32, 1653 (1967), and the values of the effective reaction rate constants have been computed. The kinetic study of active sodium carbonate of the second generation has been completed by the determination of microstructure (SEM) of solid samples before and after reaction, and by determining the solid surface composition before and after reaction by means of electronic spectra (ESCA).

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Sellitto, P., and B. Legras. "Sensitivity of thermal infrared nadir instruments to the chemical and microphysical properties of UTLS secondary sulfate aerosols." Atmospheric Measurement Techniques 9, no. 1 (January 18, 2016): 115–32. http://dx.doi.org/10.5194/amt-9-115-2016.

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Abstract. Monitoring upper-tropospheric–lower-stratospheric (UTLS) secondary sulfate aerosols and their chemical and microphysical properties from satellite nadir observations is crucial to better understand their formation and evolution processes and then to estimate their impact on UTLS chemistry, and on regional and global radiative balance. Here we present a study aimed at the evaluation of the sensitivity of thermal infrared (TIR) satellite nadir observations to the chemical composition and the size distribution of idealised UTLS sulfate aerosol layers. The extinction properties of sulfuric acid/water droplets, for different sulfuric acid mixing ratios and temperatures, are systematically analysed. The extinction coefficients are derived by means of a Mie code, using refractive indices taken from the GEISA (Gestion et Étude des Informations Spectroscopiques Atmosphériques: Management and Study of Spectroscopic Information) spectroscopic database and log-normal size distributions with different effective radii and number concentrations. IASI (Infrared Atmospheric Sounding Interferometer) pseudo-observations are generated using forward radiative transfer calculations performed with the 4A (Automatized Atmospheric Absorption Atlas) radiative transfer model, to estimate the impact of the extinction of idealised aerosol layers, at typical UTLS conditions, on the brightness temperature spectra observed by this satellite instrument. We found a marked and typical spectral signature of these aerosol layers between 700 and 1200 cm−1, due to the absorption bands of the sulfate and bisulfate ions and the undissociated sulfuric acid, with the main absorption peaks at 1170 and 905 cm−1. The dependence of the aerosol spectral signature to the sulfuric acid mixing ratio, and effective number concentration and radius, as well as the role of interfering parameters like the ozone, sulfur dioxide, carbon dioxide and ash absorption, and temperature and water vapour profile uncertainties, are analysed and critically discussed. The information content (degrees of freedom and retrieval uncertainties) of synthetic satellite observations is estimated for different instrumental configurations. High spectral resolution (IASI-like pseudo-observations) and broadband spectral features (Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI)-like pseudo-observations) approaches are proposed and discussed.

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Fleyfel, Fouad, Hugh H. Richardson, and J. Paul Devlin. "Comparative sulfur dioxide infrared spectra: type I and II clathrate hydrate films, large gas-phase clusters, and anhydrous crystalline films." Journal of Physical Chemistry 94, no. 18 (September 1990): 7032–37. http://dx.doi.org/10.1021/j100381a021.

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Dai, Z., L. K. Tseng, and G. M. Faeth. "Velocity Statistics of Round, Fully Developed, Buoyant Turbulent Plumes." Journal of Heat Transfer 117, no. 1 (February 1, 1995): 138–45. http://dx.doi.org/10.1115/1.2822294.

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An experimental study of the structure of round buoyant turbulent plumes was carried out, limited to conditions within the fully developed (self-preserving) portion of the flow. Plume conditions were simulated using dense gas sources (carbon dioxide and sulfur hexafluoride) in a still air environment. Velocity statistics were measured using laser velocimetry in order to supplement earlier measurements of mixture fraction statistics using laser-induced iodine fluorescence. Similar to the earlier observations of mixture fraction statistics, self-preserving behavior was observed for velocity statistics over the present test range (87–151 source diameters and 12–43 Morton length scales from the source), which was farther from the source than most earlier measurements. Additionally, the new measurements indicated that self-preserving plumes are narrower, with larger mean streamwise velocities near the axis (when appropriately scaled) and with smaller entrainment rates, than previously thought. Velocity statistics reported include mean and fluctuating velocities, temporal power spectra, temporal and spatial integral scales, and Reynolds stresses.

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44

Bauduin, S., L. Clarisse, J. Hadji-Lazaro, N. Theys, C. Clerbaux, and P. F. Coheur. "Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations." Atmospheric Measurement Techniques Discussions 8, no. 10 (October 26, 2015): 11029–75. http://dx.doi.org/10.5194/amtd-8-11029-2015.

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Abstract. SO2 from volcanic eruptions is now operationally monitored from space in both ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO2 has almost solely been measured from UV sounders. Indeed, TIR instruments are well-known to have a poor sensitivity to the boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO2 locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO2 near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO2 ν3 band in IASI spectra. The first step allows retrieving the peak altitude of SO2 and selecting near-surface SO2. In the second step, 0–4 km columns of SO2 are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO2 from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO2 columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to near-surface SO2. As IASI provides twice daily global measurements, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0–4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI).

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45

Iraqi, Muhammad, Norman Goldberg, and Helmut Schwarz. "Collisional cooling effects on the charge reversal and neutralization—reionization mass spectra of the negative cluster ion of sulfur dioxide (SO2) .−2." International Journal of Mass Spectrometry and Ion Processes 130, no. 1-2 (January 1994): 127–31. http://dx.doi.org/10.1016/0168-1176(93)03908-5.

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46

Bauduin, Sophie, Lieven Clarisse, Juliette Hadji-Lazaro, Nicolas Theys, Cathy Clerbaux, and Pierre-François Coheur. "Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations." Atmospheric Measurement Techniques 9, no. 2 (February 29, 2016): 721–40. http://dx.doi.org/10.5194/amt-9-721-2016.

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Abstract. SO2 from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO2 has almost solely been measured from UV sounders. Indeed, TIR instruments are well known to have a poor sensitivity to the planetary boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO2 locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO2 near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO2 ν3 band in IASI spectra. The first step allows the peak altitude of SO2 to be retrieved and near-surface SO2 to be selected. In the second step, 0–4 km columns of SO2 are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO2 from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO2 columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to near-surface SO2 in the ν3 band. As IASI provides global measurements twice daily, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0–4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI).

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47

Jafari, Abbas, Mehrban Sadeghi, Farhang Tirgir, and Mehdi Barghaei. "Photocatalytic removal of naphthalene (C10H8 ) from aqueous environments using sulfur and nitrogen doped titanium dioxide (TiO2 -N-S) coated on glass microbullets in presence of sunlight." Journal of Shahrekord University of Medical Sciences 23, no. 1 (March 30, 2021): 34–43. http://dx.doi.org/10.34172/jsums.2021.06.

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Background and aims: Due to their toxicity and carcinogenic effects, polycyclic aromatic hydrocarbons (PAHs) such as naphthalene (C10H8 ) are regarded as hazardous compounds for both humans and the environment, and it is essential to remove these contaminants from the environment. The present study aimed to remove naphthalene from a synthetic aqueous environment using sulfur and nitrogen doped titanium dioxide (TiO2 -N-S) nanoparticles (NPs) immobilized on glass microbullets under sunlight. Methods: In this experimental study, TiO2 -N-S NPs were synthesized using sol-gel process. The structure of NPs was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX), and differential reflectance spectroscopy (DRS). In addition, using statistical analyses, the effects of parameters such as the initial concentration of naphthalene, pH, contact time, and the optimal conditions on naphthalene removal were investigated. Results: XRD patterns and SEM images of the samples confirmed the size of synthesized particles in nanometer. The EDX and DRS spectra analysis showed the presence of two elements (sulfur and nitrogen) and the optical photocatalytic activity in the visible region, respectively. The maximum level of naphthalene removal in the presence of sunlight was obtained to be about 93.55% using a concentration of 0.25 g of thiourea immobilized on glass microbullets at pH=5 and contact time of 90 minutes. Conclusion: The rate of naphthalene removal using the immobilized TiO2 -N-S on glass microbullets was 93.55% in optimal conditions. Therefore, this method has an effective potential for naphthalene removal, and can be used to remove naphthalene from industrial wastewater.

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Maciołek, Urszula, Ewaryst Mendyk, Małgorzata Kosińska-Pezda, Daniel M. Kamiński, and Anna E. Kozioł. "Potassium Complexes of Quercetin-5′-Sulfonic Acid and Neutral O-Donor Ligands: Synthesis, Crystal Structure, Thermal Analysis, Spectroscopic Characterization and Physicochemical Properties." Materials 14, no. 22 (November 11, 2021): 6798. http://dx.doi.org/10.3390/ma14226798.

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The coordination ability of QSA− ligand towards potassium cations was investigated. Potassium complex of quercetin-5’-sulfonate of the general formula [KQSA(H2O)2]n was obtained. The [KQSA(H2O)2] (1) was a starting compound for solvothermal syntheses of acetone (2) and dimethylsulfoxide (3) complexes. For the crystalline complexes 1–3, crystals morphology was analyzed, IR and Raman spectra were registered, as well as thermal analysis for 1 was performed. Moreover, for 1 and 3, molecular structures were established. The potassium cations are coordinated by eight oxygen atoms (KO8) of a different chemical nature; coordinating groups are sulfonic, hydroxyl, and carbonyl of the QSA− anion, and neutral molecules—water (1) or DMSO (3). The detailed thermal studies of 1 confirmed that water molecules were strongly bonded in the complex structure. Moreover, it was stated that decomposition processes depended on the atmosphere used above 260 °C. The TG–FTIR–MS technique allowed the identification of gaseous products evolving during oxidative decomposition and pyrolysis of the analyzed compound: water vapor, carbon dioxide, sulfur dioxide, carbonyl sulfide, and carbon monoxide. The solubility studies showed that 1 is less soluble in ethanol than quercetin dihydrate in ethanol, acetone, and DMSO. The exception was aqueous solution, in which the complex exhibited significantly enhanced solubility compared to quercetin. Moreover, the great solubility of 1 in DMSO explained the ease of ligand exchange (water for DMSO) in [KQSA(H2O)2].

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Huang, Li, Qiu, Chen, Cheng, Sun, Bai, Song, Zhang, and He. "Effect of Organic Assistant on the Performance of Ceria-Based Catalysts for the Selective Catalytic Reduction of NO with Ammonia." Catalysts 9, no. 4 (April 12, 2019): 357. http://dx.doi.org/10.3390/catal9040357.

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In the present study, a series of CeO2/TiO2 catalysts were fabricated by dry ball milling method in the absence and presence of organic assistants, and their catalytic performances for the selective catalytic reduction (SCR) of NO by NH3 were investigated. It was found that the addition of organic assistants in the ball milling process and the calcining ambience exerted a significant influence on the catalytic performances of CeO2/TiO2 catalysts. The nitrogen sorption isotherm measurement (BET), powder X-ray diffraction (XRD), Raman spectra, high-resolution transmission electron microscopy (HR-TEM), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), sulfur dioxide temperature-programmed desorption (SO2-TPD), thermogravimetric analysis (TG), Fourier transform infrared (FT-IR) and X-ray photoelectron spectra (XPS) characterizations showed that the introduction of citric acid in the ball milling process could significantly change the decomposition process of the precursor mixture, which can lead to improved dispersion and reducibility of cerium species, surface acidity as well as the surface microstructure, all which were responsible for the high low temperature activity of CeTi-C-N in an NH3-SCR reaction. In contrast, the addition of sucrose in the milling process showed an inhibitory effect on the catalytic performance of CeO2/TiO2 catalyst in an NH3-SCR reaction, possibly due to the decrease of the crystallinity of the TiO2 support and the carbon residue covering the active sites.

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Fedkin, Nikita M., Can Li, Nickolay A. Krotkov, Pascal Hedelt, Diego G. Loyola, Russell R. Dickerson, and Robert Spurr. "Volcanic SO2 effective layer height retrieval for the Ozone Monitoring Instrument (OMI) using a machine-learning approach." Atmospheric Measurement Techniques 14, no. 5 (May 20, 2021): 3673–91. http://dx.doi.org/10.5194/amt-14-3673-2021.

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Abstract. Information about the height and loading of sulfur dioxide (SO2) plumes from volcanic eruptions is crucial for aviation safety and for assessing the effect of sulfate aerosols on climate. While SO2 layer height has been successfully retrieved from backscattered Earthshine ultraviolet (UV) radiances measured by the Ozone Monitoring Instrument (OMI), previously demonstrated techniques are computationally intensive and not suitable for near-real-time applications. In this study, we introduce a new OMI algorithm for fast retrievals of effective volcanic SO2 layer height. We apply the Full-Physics Inverse Learning Machine (FP_ILM) algorithm to OMI radiances in the spectral range of 310–330 nm. This approach consists of a training phase that utilizes extensive radiative transfer calculations to generate a large dataset of synthetic radiance spectra for geophysical parameters representing the OMI measurement conditions. The principal components of the spectra from this dataset in addition to a few geophysical parameters are used to train a neural network to solve the inverse problem and predict the SO2 layer height. This is followed by applying the trained inverse model to real OMI measurements to retrieve the effective SO2 plume heights. The algorithm has been tested on several major eruptions during the OMI data record. The results for the 2008 Kasatochi, 2014 Kelud, 2015 Calbuco, and 2019 Raikoke eruption cases are presented here and compared with volcanic plume heights estimated with other satellite sensors. For the most part, OMI-retrieved effective SO2 heights agree well with the lidar measurements of aerosol layer height from Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and thermal infrared retrievals of SO2 heights from the infrared atmospheric sounding interferometer (IASI). The errors in OMI-retrieved SO2 heights are estimated to be 1–1.5 km for plumes with relatively large SO2 signals (>40 DU). The algorithm is very fast and retrieves plume height in less than 10 min for an entire OMI orbit.

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Journal articles on the topic 'Sulfur dioxide Spectra'

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