scholarly journals Large volume sample system for measuring sulfur isotopic compositions of carbonyl sulfide

2018 ◽  
Author(s):  
Kazuki Kamezaki ◽  
Shohei Hattori ◽  
Enno Bahlmann ◽  
Naohiro Yoshida
Keyword(s):  
Collection Efficiency ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
Isotopic Analysis ◽  
Ambient Air ◽  
Sampling System ◽  
Abstract Knowledge ◽  
Global Signal ◽  
Significant Difference ◽  
Institute Of Technology

Abstract. Knowledge related to sulfur isotopic composition of carbonyl sulphide (OCS or COS), the most abundant atmospheric sulfur species, remains scarce. Earlier method developed for sulfur isotopic analysis for OCS using S+ fragmentation is inapplicable for ambient air samples because of the large samples required (approx. 500 L of 500 pmol mol−1 OCS). To overcome this difficulty, herein we present a new sampling system for collecting approx. 10 nmol of OCS from ambient air coupled with a purification system. Salient system features are (i) accommodation of samples up to 500 L (= approx. 10 nmol) of air at 5 L min−1, (ii) portability of 7 inch tubes (approx. 1 cm3) for preserving samples, and (iii) purification OCS from other compounds such as CO2. We tested the OCS collection efficiency of the systems and sulfur isotopic fractionation during sampling. Results show precision (1σ) of δ33S(OCS), δ34S(OCS), and Δ33S(OCS) values, respectively, as 0.4 ‰, 0.2 ‰, and 0.4 ‰. Additionally, this report presents diurnal variation of δ34S(OCS) values collected from ambient air at Suzukakedai campus of Tokyo Institute of Technology located in Yokohama, Japan. The observed OCS concentrations and δ34S(OCS) values were, respectively, 447–520 pmol mol−1 and from 10.4 ‰ to 10.7 ‰. No significant difference was found between values obtained during the day and night. The observed δ34S(OCS) values in ambient air differed greatly from previously reported values ((4.9 ± 0.3) ‰) for compressed air collected at Kawasaki, Japan, presumably because of sampling conditions and collection processes for that sample. Consequently, previous values of δ34S(OCS) = (4.9 ± 0.3) ‰ were not representative samples for a global signal. When considering (10.5 ± 0.4) ‰ is postulated as the global signal of δ34S(OCS), this revised δ34S(OCS) value is consistent with previous estimation based on terrestrial and oceanic sulfur sources. The δ34S(OCS) value explains the reported δ34S(OCS) values for background stratospheric sulfate. The system presented herein is useful for application of δ34S(OCS) for investigation of OCS sources and sinks in the troposphere to elucidate its cycle and its contribution to background stratospheric sulfate.

scholarly journals Large-volume air sample system for measuring <sup>34</sup>S∕<sup>32</sup>S isotope ratio of carbonyl sulfide

2019 ◽  
Vol 12 (2) ◽  
pp. 1141-1154 ◽  
Author(s):  
Kazuki Kamezaki ◽  
Shohei Hattori ◽  
Enno Bahlmann ◽  
Naohiro Yoshida
Keyword(s):  
Diurnal Variation ◽  
Isotope Ratio ◽  
Collection Efficiency ◽  
Anthropogenic Activities ◽  
Carbonyl Sulfide ◽  
Ambient Air ◽  
Spatial And Temporal Variation ◽  
Outer Diameter ◽  
Sampling System ◽  
Institute Of Technology

Abstract. Knowledge related to sulfur isotope ratios of carbonyl sulfide (OCS or COS), the most abundant atmospheric sulfur species, remains scarce. An earlier method developed for sulfur isotopic analysis for OCS using S+ fragmentation by an isotope ratio mass spectrometer is inapplicable for ambient air samples because of the large samples required (approx. 500 L of 500 pmol mol−1 OCS). To overcome this difficulty, herein we present a new sampling system for collecting approximately 10 nmol of OCS from ambient air coupled with a purification system. Salient system features are (i) accommodation of samples up to 500 L (approx. 10 nmol) of air at 5 L min−1; (ii) portability of adsorption tubes (1∕4 in. (0.64 cm) outer diameter, 17.5 cm length, approximately 1.4 cm3 volume) for preserving the OCS amount and δ34S(OCS) values at −80 ∘C for up to 90 days and 14 days; and (iii) purification OCS from other compounds such as CO2. We tested the OCS collection efficiency of the systems and sulfur isotopic fractionation during sampling. Results show precision (1σ) of δ34S(OCS) values as 0.4 ‰ for overall procedures during measurements for atmospheric samples. Additionally, this report presents diurnal variation of δ34S(OCS) values collected from ambient air at the Suzukakedai campus of the Tokyo Institute of Technology located in Yokohama, Japan. The observed OCS concentrations and δ34S(OCS) values were, respectively, 447–520 pmol mol−1 and from 10.4 ‰ to 10.7 ‰ with a lack of diurnal variation. The observed δ34S(OCS) values in ambient air differed greatly from previously reported values of δ34S(OCS) = (4.9±0.3) ‰ for compressed air collected at Kawasaki, Japan, presumably because of degradation of OCS in cylinders and collection processes for that sample. The difference of atmospheric δ34S(OCS) values between 10.5 ‰ in Japan (this study) and ∼13 ‰ recently reported in Israel or the Canary Islands indicates that spatial and temporal variation of δ34S(OCS) values is expected due to a link between anthropogenic activities and OCS cycles. The system presented herein is useful for application of δ34S(OCS) for investigation of OCS sources and sinks in the troposphere to elucidate its cycle.

scholarly journals Ultraviolet absorption cross sections of carbonyl sulfide isotopologues OC<sup>32</sup>S, OC<sup>33</sup>S, OC<sup>34</sup>S and O<sup>13</sup>CS: isotopic fractionation in photolysis and atmospheric implications

2011 ◽  
Vol 11 (19) ◽  
pp. 10293-10303 ◽  
Author(s):  
S. Hattori ◽  
S. O. Danielache ◽  
M. S. Johnson ◽  
J. A. Schmidt ◽  
H. G. Kjaergaard ◽  
...  
Keyword(s):  
Cross Sections ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
High Energy ◽  
Ultraviolet Absorption ◽  
Absorption Cross ◽  
Rare Isotopes ◽  
Mass Dependent ◽  
Franck Condon ◽  
Energy Side

Abstract. We report measurements of the ultraviolet absorption cross sections of OC32S, OC33S, OC34S and O13CS from 195 to 260 nm. The OCS isotopologues were synthesized from isotopically-enriched elemental sulfur by reaction with carbon monoxide. The measured cross section of OC32S is consistent with literature spectra recorded using natural abundance samples. Relative to the spectrum of the most abundant isotopologue, substitution of heavier rare isotopes has two effects. First, as predicted by the reflection principle, the Gaussian-based absorption envelope becomes slightly narrower and blue-shifted. Second, as predicted by Franck-Condon considerations, the weak vibrational structure is red-shifted. Sulfur isotopic fractionation constants (33ε, 34ε) as a function of wavelength are not highly structured, and tend to be close to zero on average on the high energy side and negative on the low energy side. The integrated photolysis rate of each isotopologue at 20 km, the approximate altitude at which most OCS photolysis occurs, was calculated. Sulfur isotopic fractionation constants at 20 km altitude are (−3.7 ± 4.5)‰ and (1.1 ± 4.2)‰ for 33ε and 34ε, respectively, which is inconsistent with the previously estimated large fractionation of over 73‰ in 34ε. This demonstrates that OCS photolysis does not produce sulfur isotopic fractionation of more than ca. 5‰, suggesting OCS may indeed be a significant source of background stratospheric sulfate aerosols. Finally, the predicted isotopic fractionation constant for 33S excess (33E) in OCS photolysis is (−4.2 ± 6.6)‰, and thus photolysis of OCS is not expected to be the source of the non-mass-dependent signature observed in modern and Archaean samples.

Isotopic constraints on the tropospheric carbonyl sulfide budget

2021 ◽  
Author(s):  
Kazuki Kamezaki ◽  
Shohei Hattori ◽  
Naohiro Yoshida
Keyword(s):  
Transport Model ◽  
Gross Primary Production ◽  
Carbonyl Sulfide ◽  
Anthropogenic Sources ◽  
Ambient Atmosphere ◽  
Chemical Transport Model ◽  
Sampling System ◽  
Keeling Plot ◽  
The Western Pacific ◽  
Sulfur Containing

&lt;p&gt;Carbonyl sulfide (OCS), the most abundant sulfur-containing gas in the ambient atmosphere, possesses great potential for tracer of the carbon cycle. Sulfur isotopic composition (&lt;sup&gt;34&lt;/sup&gt;S/&lt;sup&gt;32&lt;/sup&gt;S ratio, &amp;#948;&lt;sup&gt;34&lt;/sup&gt;S) on OCS is a feasible tool to evaluate the OCS budget. We applied the sulfur isotope measurement for the tropospheric OCS cycle and distinguished OCS sources from oceanic and anthropogenic emissions.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Here, we present a developed measurement system of &amp;#948;&lt;sup&gt;34&lt;/sup&gt;S of OCS and the result of latitudinal (north-south) observations of OCS within Japan using the method. The OCS sampling system was carried to three sampling sites in Japan: Miyakojima (24&amp;#176;8&amp;#8217;N, 125&amp;#176;3&amp;#8217;E), Yokohama (35&amp;#176;5&amp;#8217;N, 139&amp;#176;5&amp;#8217;E), and Otaru (43&amp;#176;1&amp;#8217;N, 141&amp;#176;2&amp;#8217;E). The observed &amp;#948;&lt;sup&gt;34&lt;/sup&gt;Sof OCS ranging from 9.7 to 14.5&amp;#8240; reflects the tropospheric OCS cycle. Particularly in winter, latitudinal decreases in &amp;#948;&lt;sup&gt;34&lt;/sup&gt;Svalues were found to be correlated with increases in OCS concentrations, resulting in an intercept of (4.7 &amp;#177; 0.8)&amp;#8240; in the Keeling plot approach. This trend suggests the transport of anthropogenic OCS emissions from the Asian continent to the western Pacific by the Asian monsoon outflow.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The estimated background &amp;#948;&lt;sup&gt;34&lt;/sup&gt;S of OCS in eastern Asia is consistent with the &amp;#948;&lt;sup&gt;34&lt;/sup&gt;S of OCS previously reported in Israel and the Canary Islands, suggesting that the background &amp;#948;&lt;sup&gt;34&lt;/sup&gt;S of OCS in the Northern Hemisphere ranges from 12.0 to 13.5&amp;#8240;. Our constructed sulfur isotopic mass balance of OCS revealed that anthropogenic sources, not merely oceanic sources, account for much of the missing source of atmospheric OCS. This sulfur isotopic constraint on atmospheric OCS is an important step together with isotopic characterizations and analysis using a chemical transport model, will enable detailed quantitative OCS budget and estimation of gross primary production.&lt;/p&gt;

Experimental Evaluation of Pool Fire Suppression Performance of Sodium Leak Collection Tray in Open Air

2006 ◽  
Author(s):  
F. C. Parida ◽  
P. M. Rao ◽  
S. S. Ramesh ◽  
B. Malarvizhi ◽  
V. Gopalakrishnan ◽  
...  
Keyword(s):  
Fire Protection ◽  
Collection Efficiency ◽  
Fire Suppression ◽  
Ambient Air ◽  
Thermal Fluctuations ◽  
Liquid Sodium ◽  
Drain Pipe ◽  
External Power Source ◽  
Oxygen Starvation ◽  
Breeder Reactors

In the event of sodium leakage from heat transfer circuits of fast breeder reactors (FBR), liquid sodium catches fire in ambient air leading to production of flame, smoke and heat. One of the passive fire protection methods involves immediate collection of the leaking sodium to a sodium hold-up vessel (SHV) covered with a sloping cover tray (SCT) having a few drain pipes and one vent pipe (as in Fig. 1). As soon as the liquid sodium falls on the sloping cover tray, gravity guides the sodium through drain pipes into the bottom tray in which self-extinction occurs due to oxygen starvation. This sodium fire protection equipment called leak collection tray (LCT) works without the intervention of an operator and external power source. A large number of LCTs are strategically arranged under the sodium circulating pipe lines in the FBR plants to serve as passive suppression devices. In order to test the efficacy of the LCT, four tests were conducted. Two tests were with LCT having three drain pipes and rest with one. In each experiment, nearly 40 kg of hot liquid sodium at 550 °C was discharged on the LCT in the open air. Continuous on-line monitoring of temperature at strategic locations (∼ 28 points) were carried out. Colour videography was employed for taking motion pictures of various time-dependent events like sodium dumping, appearance of flame and release of smoke through vent pipes. After self-extinction of sodium fire, the LCT was allowed to cool overnight in an argon atmosphere. Solid samples of sodium debris in the SCT and SHV were collected by manual core drilling machine. The samples were subjected to chemical analysis for determination of unburnt and burnt sodium. The results of the four tests revealed an interesting feature: LCT with three drain pipes showed far lower sodium collection efficiency and much higher sodium combustion than that with just one drain pipe. Thermal fluctuations in temperature sensor located near the tip of the drain pipe have indicated that transient freezing and remelting processes are responsible for this phenomenon. Moreover comparison of test results between present and earlier experiments has revealed that the LCT with funnel shaped SCT is superior to that with boat shaped SCT.

scholarly journals Carbon dioxide versus air insufflation enteroscopy: a systematic review and meta-analysis based on randomized controlled trials

2018 ◽  
Vol 06 (06) ◽  
pp. E637-E645 ◽  
Author(s):  
Julio Aquino ◽  
Wanderley Bernardo ◽  
Diogo de Moura ◽  
Flávio Morita ◽  
Rodrigo Rocha ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Randomized Clinical Trials ◽  
Data Extraction ◽  
Meta Analysis ◽  
Ambient Air ◽  
Quality Analysis ◽  
Cochrane Library ◽  
Eligibility Criteria ◽  
Co2 Insufflation ◽  
Significant Difference

Abstract Objectives To compare the insufflation of CO2 and ambient air in enteroscopy. Search sources The investigators researched the electronic databases MedLine, Cochrane Library, Central, LILACS, BVS, Scopus and Cinahl. The grey search was conducted in the base of theses of the University of São Paulo, books of digestive endoscopy and references of selected articles and in previous systematic revisions. Study eligibility criteria The evaluation of eligibility was performed independently, in a non-blind manner, by two reviewers, firstly by title and abstract, followed by complete text. Disagreements between the reviewers were resolved by consensus. Data collection and analysis method Through the spreadsheet of data extraction, where one author extracted the data and a second author checked the extraction. Disagreements were resolved by debate between the two reviewers. The quality analysis of the studies was performed using the Jadad score. The software RevMan 5 version 5.3 was used for the meta-analysis. Results Four randomized clinical trials were identified, totaling 473 patients submitted to enteroscopy and comparing insufflation of CO2 and ambient air. There was no statistical difference in the intubation depth between the two groups. When CO2 insufflation was reduced, there was a significant difference in pain levels 1 hour after the procedure (95 % IC, –2.49 [–4.72, –0.26], P: 0.03, I2: 20%) and 3 hours after the procedure (95% IC, –3.05 [–5.92, –0.18], P: 0.04, I2: 0 %). There was a usage of lower propofol dosage in the CO2 insufflation group, with significant difference (95 % IC, –67.68 [–115.53, –19.84], P: 0.006, I2: 0 %). There was no significant difference between the groups in relation to the use of pethidine and to the oxygen saturation. Limitations Restricted number of randomized clinical trials and nonuniformity of data were limitations to the analysis of the outcomes. Conclusion The use of CO2 as insufflation gas in enteroscopy reduces the pain levels 1 hour and 3 hours after the procedure, in addition to the reduction of the sedation (propofol) dosage used.

scholarly journals Quantitative sampling and analysis of trace elements in atmospheric aerosols: impactor characterization and Synchrotron-XRF mass calibration

2010 ◽  
Vol 3 (5) ◽  
pp. 1473-1485 ◽  
Author(s):  
A. Richard ◽  
N. Bukowiecki ◽  
P. Lienemann ◽  
M. Furger ◽  
M. Fierz ◽  
...  
Keyword(s):  
Trace Elements ◽  
Atmospheric Aerosols ◽  
Collection Efficiency ◽  
Ambient Air ◽  
Pollution Source ◽  
Data Sets ◽  
Size Segregation ◽  
Ambient Aerosols ◽  
Experimental Conditions ◽  
Time Resolved

Abstract. Identification of trace elements in ambient air can add substantial information to pollution source apportionment studies, although they do not contribute significantly to emissions in terms of mass. A method for quantitative size and time-resolved trace element evaluation in ambient aerosols with a rotating drum impactor and synchrotron radiation based X-ray fluorescence is presented. The impactor collection efficiency curves and size segregation characteristics were investigated in an experiment with oil and salt particles. Cutoff diameters were determined through the ratio of size distributions measured with two particle sizers. Furthermore, an external calibration technique to empirically link fluorescence intensities to ambient concentrations was developed. Solutions of elemental standards were applied with an ink-jet printer on thin films and area concentrations were subsequently evaluated with external wet chemical methods. These customized and reusable reference standards enable quantification of different data sets analyzed under varying experimental conditions.

Sulfur Isotopic Fractionation of Carbonyl Sulfide during Degradation by Soil Bacteria

2016 ◽  
Vol 50 (7) ◽  
pp. 3537-3544 ◽  
Author(s):  
Kazuki Kamezaki ◽  
Shohei Hattori ◽  
Takahiro Ogawa ◽  
Sakae Toyoda ◽  
Hiromi Kato ◽  
...  
Keyword(s):  
Soil Bacteria ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation

scholarly journals Particle Size-Selective Assessment of Protection of European Standard FFP Respirators and Surgical Masks against Particles-Tested with Human Subjects

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Shu-An Lee ◽  
Dong-Chir Hwang ◽  
He-Yi Li ◽  
Chieh-Fu Tsai ◽  
Chun-Wan Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Human Subjects ◽  
Strong Association ◽  
European Standard ◽  
Sampling System ◽  
Protection Level ◽  
British Standard ◽  
Surgical Masks ◽  
Significant Difference ◽  
Personal Sampling

This study was conducted to investigate the protection of disposable filtering half-facepiece respirators of different grades against particles between 0.093 and 1.61 μm. A personal sampling system was used to particle size-selectively assess the protection of respirators. The results show that about 10.9% of FFP2 respirators and 28.2% of FFP3 respirators demonstrate assigned protection factors (APFs) below 10 and 20, which are the levels assigned for these respirators by the British Standard. On average, the protection factors of FFP respirators were 11.5 to 15.9 times greater than those of surgical masks. The minimum protection factors (PFs) were observed for particles between 0.263 and 0.384 μm. No significant difference in PF results was found among FFP respirator categories and particle size. A strong association between fit factors and protection factors was found. The study indicates that FFP respirators may not achieve the expected protection level and the APFs may need to be revised for these classes of respirators.

How does acid treatment to remove carbonates affect the isotopic and elemental composition of soils and sediments?

2008 ◽  
Vol 5 (1) ◽  
pp. 33 ◽  
Author(s):  
Milena Fernandes ◽  
Evelyn Krull
Keyword(s):  
Organic Carbon ◽  
Isotopic Analysis ◽  
Isotopic Signature ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Isotopic Shifts ◽  
Soils And Sediments ◽  
Significant Difference ◽  
Acid Treatments

Environmental context. The ability to accurately determine the elemental and isotopic composition of soils and sediments has important implications to our quantitative understanding of global biogeochemical cycles. However, the analysis of organic carbon in solid matrices is a time-consuming task that requires the selective removal of carbonates, a treatment that has the potential to significantly alter the composition of the original sample. In the present work, we compare three of the most common acid treatments used for carbonate removal, and critically evaluate their effect on the content and isotopic signature of organic carbon and nitrogen in both soils and sediments. Abstract. In the present work, we compared the efficacy of three acid treatments in removing carbonates from soils and sediments for elemental and isotopic analysis. The methods tested were (1) refluxing with H2SO3; (2) in situ treatment with H2SO3 in silver capsules; and (3) treatment with HCl followed by rinsing with water. Refluxing with H2SO3 led to substantial losses of organic carbon and nitrogen, but comparatively small nitrogen isotopic shifts. The in situ treatment was inadequate for carbonate-rich samples (contents ≥30%) as a consequence of the formation of a mineral precipitate. Treatment with HCl led to substantial losses of nitrogen from carbonate-rich samples, and deviations in nitrogen isotopic signatures (δ15N) of up to 3.7‰. δ15N values showed no significant difference between acid-treated and untreated samples or between treatments, although variability was high and influenced by sample composition. Carbonate-poor samples showed no statistical difference in δ13C values between treatments, whereas carbonate-rich samples tended to be more 13C-depleted when treated with HCl, potentially suggesting the preferential preservation of 13C-depleted compounds (e.g. lipids or lignin).

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