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1
Beriula, Rhafaela Rico Bertolino, Andressa Fabrina Klauck, and Tânia Pitombo de Oliveira. "Espaço enunciativo urbano." RUA 27, no. I (April 15, 2021): 149–68. http://dx.doi.org/10.20396/rua.v27ii.8665221.
Анотація:
Este trabalho tece considerações sobre o acontecimento enunciativo ‘Projeto Pesquisa Escola Verde’ (PPEV), desenvolvido no espaço urbano da cidade de Sinop, região norte do Estado de Mato Grosso, na perspectiva teórica e metodológica da Semântica do Acontecimento. Objetiva apresentar a nomeação, a referência e a designação da formulação do nome do projeto, bem como o funcionamento enunciativo de Educação Ambiental e desenvolvimento sustentável no objeto pesquisado, através de entrevistas realizadas com os idealizadores do PPEV. O resultado deste trabalho apresenta que houve a reescrituração do projeto que possibilitou novas designações e, o funcionamento de determinadas palavras escritas no projeto, aparecem como termos de substituibilidade para a palavra ‘verde’, o que leva a considerar os espaços de enunciação e o memorável.
2
Bjork, Robert E. "Language and the Healing Arts: Some Recent Texts on Medical Writing." Journal of Technical Writing and Communication 15, no. 1 (January 1985): 49–53. http://dx.doi.org/10.2190/acbm-ppev-tmej-ml7p.
3
Salvio, Riccardo, Saverio Santi, Antonio Toffoletti та Mauro Bassetti. "Electrochemical, in silico and time-resolved EPR behaviour of semiconductive π-conjugated poly(p-phenyleneethynylenevinylene)s (PPEV)". Synthetic Metals 284 (березень 2022): 116993. http://dx.doi.org/10.1016/j.synthmet.2021.116993.
4
Frey, Matthias, Mahesh K. Sha, Frank Hase, Matthäus Kiel, Thomas Blumenstock, Roland Harig, Gregor Surawicz, et al. "Building the COllaborative Carbon Column Observing Network (COCCON): long-term stability and ensemble performance of the EM27/SUN Fourier transform spectrometer." Atmospheric Measurement Techniques 12, no. 3 (March 11, 2019): 1513–30. http://dx.doi.org/10.5194/amt-12-1513-2019.
Анотація:
Abstract. In a 3.5-year long study, the long-term performance of a mobile, solar absorption Bruker EM27/SUN spectrometer, used for greenhouse gas observations, is checked with respect to a co-located reference Bruker IFS 125HR spectrometer, which is part of the Total Carbon Column Observing Network (TCCON). We find that the EM27/SUN is stable on timescales of several years; the drift per year between the EM27/SUN and the official TCCON product is 0.02 ppmv for XCO2 and 0.9 ppbv for XCH4, which is within the 1σ precision of the comparison, 0.6 ppmv for XCO2 and 4.3 ppbv for XCH4. The bias between the two data sets is 3.9 ppmv for XCO2 and 13.0 ppbv for XCH4. In order to avoid sensitivity-dependent artifacts, the EM27/SUN is also compared to a truncated IFS 125HR data set derived from full-resolution TCCON interferograms. The drift is 0.02 ppmv for XCO2 and 0.2 ppbv for XCH4 per year, with 1σ precisions of 0.4 ppmv for XCO2 and 1.4 ppbv for XCH4, respectively. The bias between the two data sets is 0.6 ppmv for XCO2 and 0.5 ppbv for XCH4. With the presented long-term stability, the EM27/SUN qualifies as an useful supplement to the existing TCCON network in remote areas. To achieve consistent performance, such an extension requires careful testing of any spectrometers involved by application of common quality assurance measures. One major aim of the COllaborative Carbon Column Observing Network (COCCON) infrastructure is to provide these services to all EM27/SUN operators. In the framework of COCCON development, the performance of an ensemble of 30 EM27/SUN spectrometers was tested and found to be very uniform, enhanced by the centralized inspection performed at the Karlsruhe Institute of Technology prior to deployment. Taking into account measured instrumental line shape parameters for each spectrometer, the resulting average bias across the ensemble with respect to the reference EM27/SUN used in the long-term study in XCO2 is 0.20 ppmv, while it is 0.8 ppbv for XCH4. The average standard deviation of the ensemble is 0.13 ppmv for XCO2 and 0.6 ppbv for XCH4. In addition to the robust metric based on absolute differences, we calculate the standard deviation among the empirical calibration factors. The resulting 2σ uncertainty is 0.6 ppmv for XCO2 and 2.2 ppbv for XCH4. As indicated by the executed long-term study on one device presented here, the remaining empirical calibration factor deduced for each individual instrument can be assumed constant over time. Therefore the application of these empirical factors is expected to further improve the EM27/SUN network conformity beyond the scatter among the empirical calibration factors reported above.
5
Rango, Jessamy J. "A Survey of Ant Species in Three Habitats at Mount St. Helens National Volcanic Monument." Psyche: A Journal of Entomology 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/415183.
Анотація:
Ants were surveyed in three habitats at Mount St. Helens in 2008. The area most impacted by the 1980 eruption is the Pumice Plain. Less impacted is the Blowdown Zone where trees were toppled due to the blast. Two habitats were surveyed in the Pumice Plain varying in vegetation density (Pumice Plain Low-Vegetation (PPLV) and Pumice Plain High-Vegetation (PPHV)), and one habitat was surveyed in the Blowdown Zone (BDZ). Ten ant species were collected with the most species collected from the BDZ habitat and the least from the PPLV habitat. Ant abundance was higher at the BDZ and PPHV habitats than at the PPLV habitat. Ant biodiversity was highest at the BDZ habitat than at the PPHV and PPLV habitats. Significant correlations between ant community parameters and plant community parameters were also found. Few plants in the PPLV habitat may contribute to the lack of ants. High ant species richness at the BDZ habitat may be due to complex plant architecture. Results from this study suggest that ants are important focal species in tracking biotic recovery following disturbances.
6
Berezina, E. V., A. V. Vasileva, K. B. Moiseenko, N. V. Pankratova, A. I. Skorokhod, I. B. Belikov, V. A. Belousov та A. Y. Artamonov. "Near-Surface Air Content of CH<sub>4</sub>, СО<sub>2</sub>, СО and δ<sup>13</sup>C–СH<sub>4</sub> in Moscow According to <i>In Situ</i> Observations". Известия Российской академии наук. Физика атмосферы и океана 59, № 5 (1 вересня 2023): 569–84. http://dx.doi.org/10.31857/s0002351523050036.
Анотація:
Near-surface observations of air mixing ratios of CH4, CO2, CO, benzene, and δ13C–СH4 at the IAP-RAS site in Moscow for years 2018–2020 are analyzed to describe typical interannual, seasonal, and diurnal variations. The highest mixing ratios of CH4, CO2, and CO (above 2.2, 430, and 0.2 ppmv, respectively) are mostly observed in winter as a result of the seasonal maxima in the emissions of these gases from motor transport and energy sectors and the slow removal of the emissions from the near-surface air due to suppressed turbulent vertical mixing in the cold season. The highest impact of local and distant microbial emissions on the CН4 mixing ratios is observed in summer, as follows from the low δ13C–СH4 values from –50 to –60‰. The highest increase in the mixing ratios of all the measured species is associated with air transport from the industrial area located at the east – southeast from the site. The estimated emission ratios CH4/benzene = = 0.52–0.54 ppmv/ppbv, СH4/СО = 0.56–0.75 ppmv/ppmv, СО2/benzene = 77–93 ppmv/ppbv, СО2/СО = = 81–131 ppmv/ppmv, СО/benzene = 0.65–1.11 ppmv/ppbv show the prevailing contribution of emissions from motor transport and energy sectors to the content of trace gases in the near-surface air in Moscow and are consistent with other similar estimates published on the basis of observations in large cities.
7
Dhanya, G., T. S. Pranesha, K. Nagaraja, D. M. Chate, and G. Beig. "Variation of Ozone, Carbon Monoxide, and Oxides of Nitrogen at Bengaluru, India." Journal of Scientific Research 14, no. 2 (May 6, 2022): 459–70. http://dx.doi.org/10.3329/jsr.v14i2.55626.
Анотація:
The present study analyses the continuous in-situ observations of surface ozone (O3), carbon monoxide (CO), and nitrogen oxides (NOX) conducted in an urban location, Bengaluru, India, during the year 2019 (January to December). The seasonal concentration of O3 fluctuated with the highest concentrations in the summer (39.6 ppbv) and winter (40.4 ppbv) and the lowest concentrations during the monsoon (16.8 ppbv). The seasonal mixing ratio of CO showed the highest value in post-monsoon (1.71 ppmv) and lowest during monsoon (0.79 ppmv). The seasonal trend of NOX showed highest in winter (56.8 ppbv) and lowest in monsoon (22.5 ppbv). The monthly mixing ratios of O3, CO, and NOX showed distinct variability, which may be attributed to changing anthropogenic activities, planetary boundary layer processes, and local meteorology. O3 was significantly related to temperature but inversely associated with relative humidity and wind speed. The association between CO, NOX with relative humidity, temperature, wind speed showed discrete results. The (dO3/dt) in the morning and evening duration were about 5.0 ppbv/h and -4.1 ppbv/h respectively.
8
Tang, Wenfu, Avelino F. Arellano, Joshua P. DiGangi, Yonghoon Choi, Glenn S. Diskin, Anna Agustí-Panareda, Mark Parrington, et al. "Evaluating high-resolution forecasts of atmospheric CO and CO<sub>2</sub> from a global prediction system during KORUS-AQ field campaign." Atmospheric Chemistry and Physics 18, no. 15 (August 7, 2018): 11007–30. http://dx.doi.org/10.5194/acp-18-11007-2018.
Анотація:
Abstract. Accurate and consistent monitoring of anthropogenic combustion is imperative because of its significant health and environmental impacts, especially at city-to-regional scale. Here, we assess the performance of the Copernicus Atmosphere Monitoring Service (CAMS) global prediction system using measurements from aircraft, ground sites, and ships during the Korea-United States Air Quality (KORUS-AQ) field study in May to June 2016. Our evaluation focuses on CAMS CO and CO2 analyses as well as two higher-resolution forecasts (16 and 9 km horizontal resolution) to assess their capability in predicting combustion signatures over east Asia. Our results show a slight overestimation of CAMS CO2 with a mean bias against airborne CO2 measurements of 2.2, 0.7, and 0.3 ppmv for 16 and 9 km CO2 forecasts, and analyses, respectively. The positive CO2 mean bias in the 16 km forecast appears to be consistent across the vertical profile of the measurements. In contrast, we find a moderate underestimation of CAMS CO with an overall bias against airborne CO measurements of −19.2 (16 km), −16.7 (9 km), and −20.7 ppbv (analysis). This negative CO mean bias is mostly seen below 750 hPa for all three forecast/analysis configurations. Despite these biases, CAMS shows a remarkable agreement with observed enhancement ratios of CO with CO2 over the Seoul metropolitan area and over the West (Yellow) Sea, where east Asian outflows were sampled during the study period. More efficient combustion is observed over Seoul (dCO/dCO2=9 ppbv ppmv−1) compared to the West Sea (dCO/dCO2=28 ppbv ppmv−1). This “combustion signature contrast” is consistent with previous studies in these two regions. CAMS captured this difference in enhancement ratios (Seoul: 8–12 ppbv ppmv−1, the West Sea: ∼30 ppbv ppmv−1) regardless of forecast/analysis configurations. The correlation of CAMS CO bias with CO2 bias is relatively high over these two regions (Seoul: 0.64–0.90, the West Sea: ∼0.80) suggesting that the contrast captured by CAMS may be dominated by anthropogenic emission ratios used in CAMS. However, CAMS shows poorer performance in terms of capturing local-to-urban CO and CO2 variability. Along with measurements at ground sites over the Korean Peninsula, CAMS produces too high CO and CO2 concentrations at the surface with steeper vertical gradients (∼0.4 ppmv hPa−1 for CO2 and 3.5 ppbv hPa−1 for CO) in the morning samples than observed (∼0.25 ppmv hPa−1 for CO2 and 1.7 ppbv hPa−1 for CO), suggesting weaker boundary layer mixing in the model. Lastly, we find that the combination of CO analyses (i.e., improved initial condition) and use of finer resolution (9 km vs. 16 km) generally produces better forecasts.
9
Martirosyan, Hosam El din Aboul Anean, Dina M. D. Bader, M. Al-Dossari, N. S. Abd EL-Gawaad, Heba A. Shaat, and L. O. Mallasy. "Nano edible coatings and films combined with zinc oxide and pomegranate peel active phenol compounds to prolong shelf life of minimally processed pomegranates." Dietary Supplements and Nutraceuticals 2, no. 3 (March 3, 2023): 1. http://dx.doi.org/10.31989/dsn.v2i3.1087.
Анотація:
ABSTRACTEdible coating and film from chitosan and incorporating it with the action of ZnONPs on active phenol compounds from extracts of pomegranate peel (PPE). The physical and chemical properties of edible films made with zinc oxide ZnONPs and active phenol compounds extracted from pomegranate peel (PPE) were studied. Adding ZnONPs with active phenol compounds from extracted pomegranate peel (PPE) to chitosan films can provide safe edible films, decrease microbial growth, consequently, prolong the shelf life of pomegranates, and improve the physiochemical stability of the pomegranate. The substances used in this experiment were film with a (A) extract of pomegranate peels (PPE), 5% (0.1%), (B)ZnONPs 1% (0.02%), (C) ZnONPs 2% (0.04%), (D) ZnONPs 3% (0.06%), (E) ZnONPs 1%/PPE1% (0.02%), (F) ZnONPs 2%/PPE2% (0.04%), (G) ZnONPs 3%/PPE3% (0.06%) wt% of chitosan on quality attributes and prolonging the shelf life of pomegranates were stored in edible film containers at 2 °C and 90–95% relative humidity for 20 days. The treatments of (G) ZnONPs 3%/PPE3% (0.06%) loaded on chitosan as well as chitosan and (D) ZnONPs 3% (0.06%) reduced the weight loss, had excellent microbial counts until 20 days of storage, and recorded the lowest microbial count and mold & yeast colonies. Other chemical properties studied included total soluble solids content, acidity, anthocyanin content, firmness, and ascorbic acid. Results indicated that ZnONPs 3%/PPE3% (0.06%) loaded on chitosan or ZnONPs 3% (0.06%) were the best treatments for preserving pomegranate arils. It was found that the best measurements were that the film-forming nano emulsion solutions decreased by E = 110 nm and B = 134 nm. Nano-edibles followed treatment, at F% 188.7 nm, compared to nano-edible films, which were A0% 1312 nm. Background:The substances used in this experiment were film with a (A) extract of pomegranate peels (PPE), 5% (0.1%), (B) ZnONPs 1% (0.02%), (C) ZnONPs 2% (0.04%), (D) ZnONPs 3% (0.06%), (E) ZnONPs 1%/PPE1% (0.02%), (F) ZnONPs 2%/PPE2% (0.04%), (G) ZnONPs 3%/PPE3% (0.06%) wt% of chitosan on quality attributes and prolonging the shelf life of pomegranates were stored in plastic containers at 2 °C and 90–95% relative humidity for 20 days.Objectives: to produce nano-edible films from zinc oxide and active phenol compounds of PPE nanoparticles loaded on chitosan films. The physical and mechanical properties, including viscosity, vapor, zeta particle size emulsion, color, light transmittance, and SEM, were studied to select the best edible coating for improving pomegranate fruit storability under cold storage, as well as minimizing decay and microbial growth during the storage period.Methods:The physical and chemical properties of edible films made with zinc oxide ZnONPs and active phenol compounds extracted from pomegranate peel (PPE) were studied.(A) = PPE extracts, 5% (0.1%) wt% chitosan (B) = ZnONPs, 1% (0.02%) wt% chitosan (C) = ZnONPs, 2% (0.04%) chitosan (D) weight percent = ZnONPs, 3% (0.06%) wt% chitosan weight (E) = ZnONPs 1%/PPE1% (0.02%) 2% ZnONPs/2% PPE (0.04%) Chitosan weight (F) Chitosan weight (G) = ZnONPs 3%/PPE3% (0.06%) Chitosan weight n.s. stands for "not significantly."Results: The treatments of (G) ZnONPs 3%/PPE3% (0.06%) loaded on chitosan as well as chitosan and (D) ZnONPs 3% (0.06%) reduced the weight loss, had excellent microbial counts until 20 days of storage, and recorded the lowest microbial count and mould & yeast colonies. Other chemical properties studied included total soluble solids content, acidity, anthocyanin content, firmness, and ascorbic acid. Results indicated that ZnONPs 3%/PPE3% (0.06%) loaded on chitosan or ZnONPs 3% (0.06%) were the best treatments for preserving pomegranate arils. It was found that the best measurements were that the film-forming nano emulsion solutions decreased by E = 110 nm and B = 134 nm. Nano-edibles followed treatment, at F% 188.7 nm, compared to nano-edible films, which were A0% 1312 nm.Conclusion:Physical and chemical properties were studied, e.g., rheological properties and parathyroid size distribution, zeta potential, and scanning electron microscopy films. Adding nanomaterials to edible coatings prolongs product shelf life, reduces the risk of pathogen growth, and improves the quality of fruit and vegetable surfaces by using low-cost substrates for nano-polymer production to produce edible coatings and film solutions. As this substance inhibits microbial growth and oxidation and improves the quality of the film to preserve the film from oxidation and microbial contamination, maintain the stability of the film, and extend the shelf life of food; acceptable sensory characteristics; appropriate barrier properties (CO2, O2, and water); microbial biochemical and physico-chemical stability; safety and health; and an effective carrier for antioxidants.Keywords: chitosan; ZnONP; pomegranate; mechanical; viscosity; vapor; zeta particle size; color; light transmittance; scanning electron microscopy and Nano-edible Coatings and Films.
10
O'Shea, S. J., S. J. B. Bauguitte, M. W. Gallagher, D. Lowry, and C. J. Percival. "Development of a cavity enhanced absorption spectrometer for airborne measurements of CH<sub>4</sub> and CO<sub>2</sub>." Atmospheric Measurement Techniques Discussions 6, no. 1 (January 2, 2013): 1–41. http://dx.doi.org/10.5194/amtd-6-1-2013.
Анотація:
Abstract. High-resolution CH4 and CO2 measurements were made onboard the FAAM BAe 146 UK atmospheric research aircraft during a number of field campaigns. The system was based on an infrared spectrometer using the cavity enhanced absorption spectroscopy technique. Correction functions to convert the mole fractions retrieved from the spectroscopy to dry air mole fractions were derived using laboratory experiments and over a 3 month period showed good stability. Long-term performance of the system was monitored using WMO traceable calibration gases. During the first year of operation (29 flights) analysis of the system's in-flight calibrations suggest that its measurements are accurate to −0.07 ppbv (1 σ precision at 1 Hz = 2.48 ppbv) for CH4 and −0.06 ppmv (1 σ precision at 1 Hz = 0.66 ppmv) for CO2. The system was found to be very robust, no major motion or altitude dependency could be detected in the measurements. An inter-comparison between whole air samples that were analysed post-flight for CH4 and CO2 by cavity ring down spectroscopy showed a mean difference between the two techniques of −2.4 ppbv (1 σ = 2.3 ppbv) for CH4 and −0.22 ppmv (1 σ = 0.45 ppmv) for CO2. In September 2012, the system was used to sample biomass burning plumes in Brazil as part of the SAMBBA project (South American biomass burning analysis). From these and simultaneous CO measurements, emission factors for savannah fires were calculated. These were found to be 2.2 ± 0.2 g (kg dry matter)−1 for CH4 and 1710 ± 171 g (kg dry matter)−1 for CO2, which are in excellent agreement with previous estimates in the literature.
11
Anean, Hosam Aboul, L. O. Mallasiy, Dina M. D. Bader, and Heba A. Shaat. "Nano Edible Coatings and Films Combined with Zinc Oxide and Pomegranate Peel Active Phenol Compounds Has Been to Extend the Shelf Life of Minimally Processed Pomegranates." Materials 16, no. 4 (February 13, 2023): 1569. http://dx.doi.org/10.3390/ma16041569.
Анотація:
Edible coating and film from chitosan and incorporating it with the action of ZnONPs on active phenol compounds from extracts of pomegranate peel (PPE) The physical and chemical properties of edible films composed of zinc oxide ZnONPs and active phenol compounds extracted from pomegranate peel (PPE) were investigated. Adding ZnONPs with active phenol compounds from extracted pomegranate peel(PPE) to chitosan films can provide safe edible films, decrease microbial growth and consequently prolong the shelf life of pomegranates, as well as improve the physiochemical stability of the pomegranate. The substances used in this experiment were film with a (A) extract of pomegranate peels (PPE), 5% (0.1%), (B)ZnONPs 1% (0.02%), (C) ZnONPs 2% (0.04%), (D) ZnONPs 3% (0.06%), (E) ZnONPs 1%/PPE1% (0.02%), (F) ZnONPs 2%/PPE2% (0.04%), (G) ZnONPs 3%/PPE3% (0.06%) wt% of chitosan on quality attributes and prolonging the shelf life of pomegranates were stored in plastic containers at 2 °C and 90–95% relative humidity for 20 days. The treatments of (G) ZnONPs 3%/PPE3% (0.06%) loaded on chitosan as well as chitosan and (D) ZnONPs 3% (0.06%) reduced the weight loss, had excellent microbial count until 20 days of storage, and recorded the lowest microbial count and mould & yeast colonies. Other chemical properties, such as total soluble solids content, acidity, anthocyanin content, firmness, and ascorbic acid, were investigated. Results indicated that ZnONPs 3%/PPE3% (0.06%) loaded on chitosan or ZnONPs 3% (0.06%) are the best treatments for preserving pomegranate arils. It was found that the best measurements were that the film-forming nan emulsion solutions decreased by E% 110 nm and B% 134 nm. Nano followed treatment, F% 188.7 nm, compared to nano edible films, which were A 0% 1312 nm.
12
Nakazawa, Takakiyo, Toshinobu Machida, Kenji Esumi, Masayuki Tanaka, Yoshiyuki Fujii, Shuhji Aoki, and Okitsugu Watanabe. "Measurements of CO2 and CH4 concentrations in air in a polar ice core." Journal of Glaciology 39, no. 132 (1993): 209–15. http://dx.doi.org/10.1017/s0022143000015860.
Анотація:
AbstractDry and wet air-extraction systems and precise analysis systems of the CO2and CH4concentrations for a polar ice core were developed to reconstruct their ancient levels. A dry-extraction system was capable of crushing an ice sample of 1000 g into fine powder within 2 min, and its air-extraction efficiency was found to be 98%. The CO2and CH4concentrations of extracted air were determined using gas chromatography with a flame-ionized detector. The overall precision of our measurements, including air extraction, was estimated to be better than ± 1 ppmv for CO2and + 10 ppbv for CH4. Preliminary analysis of the ice core drilled at Mizuho Station, Antarctica, showed that the CO2and CH4concentrations at 3340–3700 year BP were about 280 ppmv and 700ppbv, respectively. The Yamato core drilled at the terminus of the glacial flow near the Yamato Mountains, Antarctica, yielded concentrations of 230–240 ppmv for CO2and 520–550 ppbv for CH4, suggesting that the core had formed during the glacial period.
13
Nakazawa, Takakiyo, Toshinobu Machida, Kenji Esumi, Masayuki Tanaka, Yoshiyuki Fujii, Shuhji Aoki, and Okitsugu Watanabe. "Measurements of CO2 and CH4 concentrations in air in a polar ice core." Journal of Glaciology 39, no. 132 (1993): 209–15. http://dx.doi.org/10.3189/s0022143000015860.
Анотація:
AbstractDry and wet air-extraction systems and precise analysis systems of the CO2 and CH4 concentrations for a polar ice core were developed to reconstruct their ancient levels. A dry-extraction system was capable of crushing an ice sample of 1000 g into fine powder within 2 min, and its air-extraction efficiency was found to be 98%. The CO2 and CH4 concentrations of extracted air were determined using gas chromatography with a flame-ionized detector. The overall precision of our measurements, including air extraction, was estimated to be better than ± 1 ppmv for CO2 and + 10 ppbv for CH4. Preliminary analysis of the ice core drilled at Mizuho Station, Antarctica, showed that the CO2 and CH4 concentrations at 3340–3700 year BP were about 280 ppmv and 700ppbv, respectively. The Yamato core drilled at the terminus of the glacial flow near the Yamato Mountains, Antarctica, yielded concentrations of 230–240 ppmv for CO2 and 520–550 ppbv for CH4, suggesting that the core had formed during the glacial period.
14
Larsson, Richard, Yasuko Kasai, Takeshi Kuroda, Shigeru Sato, Takayoshi Yamada, Hiroyuki Maezawa, Yutaka Hasegawa, Toshiyuki Nishibori, Shinichi Nakasuka, and Paul Hartogh. "Mars submillimeter sensor on microsatellite: sensor feasibility study." Geoscientific Instrumentation, Methods and Data Systems 7, no. 4 (December 14, 2018): 331–41. http://dx.doi.org/10.5194/gi-7-331-2018.
Анотація:
Abstract. We present a feasibility study for a submillimeter instrument on a small Mars platform now under construction. The sensor will measure the emission from atmospheric molecular oxygen, water, ozone, and hydrogen peroxide in order to retrieve their volume mixing ratios and the changes therein over time. In addition to these, the instrument will be able to limit the crustal magnetic field, and retrieve temperature and wind speed with various degrees of precision and resolution. The expected measurement precision before spatial and temporal averaging is 15 to 25 ppmv for the molecular oxygen mixing ratio, 0.2 ppmv for the gaseous water mixing ratio, 2 ppbv for the hydrogen peroxide mixing ratio, 2 ppbv for the ozone mixing ratio, 1.5 to 2.5 µT for the magnetic field strength, 1.5 to 2.5 K for the temperature profile, and 20 to 25 m s−1 for the horizontal wind speed.
15
Verma, R. L., L. K. Sahu, Y. Kondo, N. Takegawa, S. Han, J. S. Jung, Y. J. Kim, et al. "Temporal variation of elemental carbon in Guangzhou, China, in summer 2006." Atmospheric Chemistry and Physics Discussions 9, no. 6 (November 18, 2009): 24629–67. http://dx.doi.org/10.5194/acpd-9-24629-2009.
Анотація:
Abstract. In situ measurements of the mass concentration of elemental carbon (EC) and mixing ratios of carbon monoxide (CO) and carbon dioxide (CO2) were made at Guangzhou, an urban measurement site in the Pearl River Delta (PRD), China, in July 2006. The average±standard deviation (SD) concentrations of EC, CO, and CO2 were 4.7±2.3 μg C m−3, 798±459 ppbv and 400±13 ppmv, respectively. The trends of these species were mainly controlled by synoptic-scale changes in meteorology during the campaign. Based on back trajectories, data are analyzed separately for two different air mass types representing northerly and southerly flows. Northerly air masses, constituting about 25% of the campaign, were mainly impacted by stagnant conditions, resulting in elevated levels of pollutants. On the other hand, southerly air masses measured during most of the campaign were mostly influenced by clean marine air. The diurnal patterns of EC, CO, and CO2 exhibited peak concentrations during the morning and evening hours coinciding with rush-hour traffic. The diurnal variations of EC and ΔEC/ΔCO closely followed the traffic pattern of heavy-duty vehicles (HDV) in Guangzhou, similar to that observed in Beijing. The level of EC in this campaign was similar to values reported during previous studies at other sites surrounding Guangzhou. The average slopes of ΔEC/ΔCO, ΔEC/ΔCO2, and ΔCO/ΔCO2 were 0.0054 μg C m−3/ppbv, 0.15 μg C m−3/ppmv, and 46.4 ppbv/ppmv, respectively, agreeing reasonably well with their respective emission ratios derived from regional emission inventories.
16
Mao, Jie, Qian Liu, Shujing Wang, Xin Lv, Yi Huang, Yanfeng Ma, Yongsheng Chen, and Shougen Yin. "The Influence of Poly(phenyleneethynylene) Side Chain Structure on Single-Walled Carbon Nanotubes Hybrid Photovoltaic Cells." Journal of Nanoscience and Nanotechnology 8, no. 7 (July 1, 2008): 3343–50. http://dx.doi.org/10.1166/jnn.2008.131.
Анотація:
A novel poly(phenyleneethynylene)/single walled carbon nanotubes (SWNTs) donor-acceptor nanohybrid system was constructed based on the bulk heterojunction concept, and their photovoltaic (PV) properties were studied. Comparing with that of the pristine polymer poly(phenyleneethynylene) (PPE) device, the PV performance of the SWNTs/PPE hybrid is dramatically improved. The origin of open-circuit voltage (Voc) of the pristine polymer PPE device and SWNTs/PPE device was explained by metal-insulator-metal (MIM) diode model and pinning mechanism, respectively. Furthermore, incorporation of sensitizing groups to the side chain of PPE has great effect on the photovoltaic cell performance based on these hybrid materials and both the short-circuit current density (Isc) and power conversion efficiency are significantly enhanced. It is proposed that the main reason for the increase of short circuit current is due to efficient transfer of holes by sensitizer to PPE backbone and the transfer of electrons to the SWNTs. The power conversion efficiency is enhanced by ∼1 order magnitude to 0.031% for the device based on the PPE3 with anthracene sensitizer group on the side chain compared with that (4.2 × 10−3% for SWNTs/PPE1 and 6.2 × 10−3% for SWNTs/PPE2) of the device without anthracene sensitizer on the side chain.
17
Kohl, Lukas, Markku Koskinen, Kaisa Rissanen, Iikka Haikarainen, Tatu Polvinen, Heidi Hellén, and Mari Pihlatie. "Technical note: Interferences of volatile organic compounds (VOCs) on methane concentration measurements." Biogeosciences 16, no. 17 (September 4, 2019): 3319–32. http://dx.doi.org/10.5194/bg-16-3319-2019.
Анотація:
Abstract. Studies that quantify plant methane (CH4) emission rely on the accurate measurement of small changes in the mixing ratio of CH4 that coincide with much larger changes in the mixing ratio of volatile organic compounds (VOCs). Here, we assessed whether 11 commonly occurring VOCs (e.g. methanol, α- and β-pinene, Δ3-carene) interfered with the quantitation of CH4 by five laser-absorption spectroscopy and Fourier-transformed infrared spectroscopy (FTIR) based CH4 analysers, and quantified the interference of seven compounds on three instruments. Our results showed minimal interference with laser-based analysers and underlined the importance of identifying and compensating for interferences with FTIR instruments. When VOCs were not included in the spectral library, they exerted a strong bias on FTIR-based instruments (64–1800 ppbv apparent CH4 ppmv−1 VOC). Minor (0.7–126 ppbv ppmv−1) interference with FTIR-based measurements were also detected when the spectrum of the interfering VOC was included in the library. In contrast, we detected only minor (<20 ppbv ppmv−1) and transient (< 1 min) VOC interferences on laser-absorption spectroscopy-based analysers. Overall, our results demonstrate that VOC interferences have only minor effects on CH4 flux measurements in soil chambers, but may severely impact stem and shoot flux measurements. Laser-absorption-based instruments are better suited for quantifying CH4 fluxes from plant leaves and stems than FTIR-based instruments; however, significant interferences in shoot chamber measurements could not be excluded for any of the tested instruments. Our results furthermore showed that FTIR can precisely quantify VOC mixing ratios and could therefore provide a method complementary to proton-transfer-reaction mass spectrometry (PTR-MS).
18
Verma, R. L., L. K. Sahu, Y. Kondo, N. Takegawa, S. Han, J. S. Jung, Y. J. Kim, et al. "Temporal variations of black carbon in Guangzhou, China, in summer 2006." Atmospheric Chemistry and Physics 10, no. 14 (July 16, 2010): 6471–85. http://dx.doi.org/10.5194/acp-10-6471-2010.
Анотація:
Abstract. In situ measurements of the mass concentration of black carbon (BC) and mixing ratios of carbon monoxide (CO) and carbon dioxide (CO2) were made at Guangzhou, an urban measurement site in the Pearl River Delta (PRD), China, in July 2006. The average ± standard deviation (SD) concentrations of BC, CO, and CO2 were 4.7± 2.3 μgC m−3, 798± 459 ppbv, and 400± 13 ppmv, respectively. The trends of these species were mainly controlled by synoptic-scale changes in meteorology during the campaign. Based on back trajectories, data are analyzed separately for two different air mass types representing northerly and southerly flows. The northerly air masses, which constituted ~25% of the campaign, originated mostly in the PRD and hence represent observations on regional scales. On the other hand, during southerly flow (~75%), the measurements were influenced by dilution due to cleaner marine air. The diurnal patterns of BC, CO, and CO2 exhibited peak concentrations during the morning and evening hours coinciding with rush-hour traffic. The ratios of OC/BC were lower during the morning hour peaks in the concentrations of primary pollutants due to their fresh emissions mainly from vehicular traffic in Guangzhou. The diurnal variations of BC observed in southerly air masses tended to follow the traffic patterns of heavy-duty vehicles (HDV) in Guangzhou, while the roles of other sources need to be investigated. The slopes of ΔBC/ΔCO, ΔBC/ΔCO2, and ΔCO/ΔCO2 observed during northerly flows were 0.0045 μgC m−3/ppbv, 0.13 μgC m−3/ppmv, and 49.4 ppbv/ppmv, respectively, agreeing reasonably with their respective emission ratios derived from regional emission inventories.
19
Kuttippurath, J., S. Godin-Beekmann, F. Lefèvre, G. Nikulin, M. L. Santee, and L. Froidevaux. "Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997." Atmospheric Chemistry and Physics Discussions 12, no. 3 (March 6, 2012): 6877–908. http://dx.doi.org/10.5194/acpd-12-6877-2012.
Анотація:
Abstract. We present a detailed discussion of the chemical and dynamical processes in the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical transport model (CTM) simulations and space-based observations. In the Arctic winter 2010/2011, the lower stratospheric minimum temperatures were below 195 K for a record period, from December to mid-April, and a strong and stable vortex was present during that period. Analyses with the Mimosa-Chim CTM simulations show that the chemical ozone loss started by early January and progressed slowly to 1 ppmv (parts per million by volume) by late February. The loss intensified by early March and reached a record maximum of ~2.4 ppmv in the late March–early April period over a broad altitude range of 450–550 K. This coincides with elevated ozone loss rates of 2–4 ppbv sh−1 (parts per billion by volume/sunlit hour) and a contribution of about 40% from the ClO–ClO cycle and about 35–40% from the ClO-BrO cycle in late February and March, and about 30–50% from the HOx cycle in April. We also estimate a loss of around 0.7–1.2 ppmv contributed (75%) by the NOx cycle at 550–700 K. The ozone loss estimated in the partial column range of 350–550 K also exhibits a record value of ~148 DU (Dobson Unit). This is the largest ozone loss ever estimated in the Arctic and is consistent with the remarkable chlorine activation and strong denitrification (40–50%) during the winter, as the modeled ClO shows ~1.8 ppbv in early January and ~1 ppbv in March at 450–550 K. These model results are in excellent agreement with those found from the Aura Microwave Limb Sounder observations. Our analyses also show that the ozone loss in 2010/2011 is close to that found in some Antarctic winters, for the first time in the observed history. Though the winter 1996/1997 was also very cold in March–April, the temperatures were higher in December–February, and, therefore, chlorine activation was moderate and ozone loss was average with about 1.2 ppmv at 475–550 K or 42 DU at 350–550 K, as diagnosed from the model simulations and measurements.
20
Dittmer, J. J., K. Petritsch, E. A. Marseglia, R. H. Friend, H. Rost, and A. B. Holmes. "Photovoltaic properties of MEH-PPV/PPEI blend devices." Synthetic Metals 102, no. 1-3 (June 1999): 879–80. http://dx.doi.org/10.1016/s0379-6779(98)00852-2.
21
Chauhan, S., M. Höpfner, G. P. Stiller, T. von Clarmann, B. Funke, N. Glatthor, U. Grabowski, et al. "MIPAS reduced spectral resolution UTLS-1 mode measurements of temperature, O<sub>3</sub>, HNO<sub>3</sub>, N<sub>2</sub>O, H<sub>2</sub>O and relative humidity over ice: retrievals and comparison to MLS." Atmospheric Measurement Techniques Discussions 2, no. 1 (February 25, 2009): 439–87. http://dx.doi.org/10.5194/amtd-2-439-2009.
Анотація:
Abstract. During several periods since 2005 the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat has performed observations dedicated to the region of the upper troposphere/lower stratosphere (UTLS). For the duration of November/December 2005 global distributions of temperature and several trace gases from MIPAS UTLS-1 mode measurements have been retrieved using the IMK/IAA (Institut für Meteorologie und Klimaforschung/Instituto de Astrofísica de Andalucía) scientific processor. In the UTLS region a vertical resolution of 2.5 to 3 km has been achieved. The retrieved temperature, H2O, O3, HNO3, N2O, and relative humidity over ice are intercompared with the Microwave Limb Sounder (MLS/Aura) v2.2 data. In general, MIPAS and MLS temperatures agree within ±4 K over the whole pressure range of 316–0.68 hPa. Systematic, latitude-independent differences of −2 to −4 K (MIPAS-MLS) at 121 hPa are explained by previously observed biases in the MLS v2.2 temperature retrievals. Temperature differences of −4 K up to 12 K above 10.0 hPa are present similarly in MIPAS and MLS with respect to ECMWF (European Centre for Medium-Range Weather Forecasts) and are likely due to deficiencies of the ECMWF analysis data. MIPAS and MLS stratospheric volume mixing ratios (vmr) of H2O agree within ±1 ppmv, with indication of oscillations between 146 and 26 hPa in the MLS dataset. Tropical upper tropospheric values of relative humidity over ice measured by the two instruments differ by ±20% in the pressure range ~146 to 68 hPa. These differences are mainly caused by the MLS temperature biases. Ozone mixing ratios agree within 0.5 ppmv (10 to 20%) between 68 and 14 hPa. At pressures smaller than 10 hPa, MIPAS O3 vmr are higher than MLS by an average of 0.5 ppmv (10%). General agreement between MIPAS and MLS HNO3 is within the range of −1.0 (−10%) to 1.0 ppbv (20%). MIPAS HNO3 is 1.0 ppbv (10%) higher compared to MLS in the height range of 46 to 10 hPa over the Northern Hemisphere. Over the tropics at 31.6 hPa MLS shows a low bias of more than 1 ppbv (>50%). In general, MIPAS and MLS N2O vmr agree within 20 to 40 ppbv (20 to 40%). Differences in the height range between 100 to 21 hPa are attributed to a known 20% positive bias in MIPAS N2O data.
22
Kuttippurath, J., S. Godin-Beekmann, F. Lefèvre, M. L. Santee, L. Froidevaux, and A. Hauchecorne. "Variability of Antarctic ozone loss in the last decade (2004–2013): high resolution simulations compared to Aura MLS observations." Atmospheric Chemistry and Physics Discussions 14, no. 20 (November 13, 2014): 28203–30. http://dx.doi.org/10.5194/acpd-14-28203-2014.
Анотація:
Abstract. A detailed analysis of the polar ozone loss processes during ten recent Antarctic winters is presented with high resolution Mimosa-Chim model simulations and high frequency polar vortex observations from the Aura Microwave Limb Sounder (MLS) instrument. Our model results for the Antarctic winters 2004–2013 show that chemical ozone loss starts in the edge region of the vortex at equivalent latitudes (EqLs) of 65–69° S in mid-June/July. The loss progresses with time at higher EqLs and intensifies during August–September over the range 400–600 K. The loss peaks in late September/early October, where all EqLs (65–83°) show similar loss and the maximum loss (>2 ppmv [parts per million by volume]) is found over a broad vertical range of 475–550 K. In the lower stratosphere, most winters show similar ozone loss and production rates. In general, at 500 K, the loss rates are about 2–3 ppbv sh−1 (parts per billion by volume/sunlit hour) in July and 4–5 ppbv sh−1 in August/mid-September, while they drop rapidly to zero by late September. In the middle stratosphere, the loss rates are about 3–5 ppbv sh−1 in July–August and October at 675 K. It is found that the Antarctic ozone hole (June–September) is controlled by the halogen cycles at about 90–95% (ClO–ClO, BrO–ClO, and ClO–O) and the loss above 700 K is dominated by the NOx cycle at about 70–75%. On average, the Mimosa-Chim simulations show that the very cold winters of 2005 and 2006 exhibit a maximum loss of ~3.5 ppmv around 550 K or about 149–173 DU over 350–850 K and the warmer winters of 2004, 2010, and 2012 show a loss of ~2.6 ppmv around 475–500 K or 131–154 DU over 350–850 K. The winters of 2007, 2008, and 2011 were moderately cold and thus both ozone loss and peak loss altitudes are between these two ranges (3 ppmv around 500 K or 150 ± 10 DU). The modeled ozone loss values are in reasonably good agreement with those estimated from Aura MLS measurements, but the model underestimates the observed ClO, largely due to the slower vertical descent in the model during spring.
23
Kuttippurath, J., S. Godin-Beekmann, F. Lefèvre, M. L. Santee, L. Froidevaux, and A. Hauchecorne. "Variability in Antarctic ozone loss in the last decade (2004–2013): high-resolution simulations compared to Aura MLS observations." Atmospheric Chemistry and Physics 15, no. 18 (September 22, 2015): 10385–97. http://dx.doi.org/10.5194/acp-15-10385-2015.
Анотація:
Abstract. A detailed analysis of the polar ozone loss processes during 10 recent Antarctic winters is presented with high-resolution MIMOSA–CHIM (Modèle Isentrope du transport Méso-échelle de l'Ozone Stratosphérique par Advection avec CHIMie) model simulations and high-frequency polar vortex observations from the Aura microwave limb sounder (MLS) instrument. The high-frequency measurements and simulations help to characterize the winters and assist the interpretation of interannual variability better than either data or simulations alone. Our model results for the Antarctic winters of 2004–2013 show that chemical ozone loss starts in the edge region of the vortex at equivalent latitudes (EqLs) of 65–67° S in mid-June–July. The loss progresses with time at higher EqLs and intensifies during August–September over the range 400–600 K. The loss peaks in late September–early October, when all EqLs (65–83° S) show a similar loss and the maximum loss (> 2 ppmv – parts per million by volume) is found over a broad vertical range of 475–550 K. In the lower stratosphere, most winters show similar ozone loss and production rates. In general, at 500 K, the loss rates are about 2–3 ppbv sh−1 (parts per billion by volume per sunlit hour) in July and 4–5 ppbv sh−1 in August–mid-September, while they drop rapidly to 0 by mid-October. In the middle stratosphere, the loss rates are about 3–5 ppbv sh−1 in July–August and October at 675 K. On average, the MIMOSA–CHIM simulations show that the very cold winters of 2005 and 2006 exhibit a maximum loss of ~ 3.5 ppmv around 550 K or about 149–173 DU over 350–850 K, and the warmer winters of 2004, 2010, and 2012 show a loss of ~ 2.6 ppmv around 475–500 K or 131–154 DU over 350–850 K. The winters of 2007, 2008, and 2011 were moderately cold, and thus both ozone loss and peak loss altitudes are between these two ranges (3 ppmv around 500 K or 150 ± 10 DU). The modeled ozone loss values are in reasonably good agreement with those estimated from Aura MLS measurements, but the model underestimates the observed ClO, largely due to the slower vertical descent in the model during spring.
24
Kuttippurath, J., S. Godin-Beekmann, F. Lefèvre, G. Nikulin, M. L. Santee, and L. Froidevaux. "Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997." Atmospheric Chemistry and Physics 12, no. 15 (August 6, 2012): 7073–85. http://dx.doi.org/10.5194/acp-12-7073-2012.
Анотація:
Abstract. We present a detailed discussion of the chemical and dynamical processes in the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical transport model (CTM) simulations and space-based observations. In the Arctic winter 2010/2011, the lower stratospheric minimum temperatures were below 195 K for a record period of time, from December to mid-April, and a strong and stable vortex was present during that period. Simulations with the Mimosa-Chim CTM show that the chemical ozone loss started in early January and progressed slowly to 1 ppmv (parts per million by volume) by late February. The loss intensified by early March and reached a record maximum of ~2.4 ppmv in the late March–early April period over a broad altitude range of 450–550 K. This coincides with elevated ozone loss rates of 2–4 ppbv sh−1 (parts per billion by volume/sunlit hour) and a contribution of about 30–55% and 30–35% from the ClO-ClO and ClO-BrO cycles, respectively, in late February and March. In addition, a contribution of 30–50% from the HOx cycle is also estimated in April. We also estimate a loss of about 0.7–1.2 ppmv contributed (75%) by the NOx cycle at 550–700 K. The ozone loss estimated in the partial column range of 350–550 K exhibits a record value of ~148 DU (Dobson Unit). This is the largest ozone loss ever estimated in the Arctic and is consistent with the remarkable chlorine activation and strong denitrification (40–50%) during the winter, as the modeled ClO shows ~1.8 ppbv in early January and ~1 ppbv in March at 450–550 K. These model results are in excellent agreement with those found from the Aura Microwave Limb Sounder observations. Our analyses also show that the ozone loss in 2010/2011 is close to that found in some Antarctic winters, for the first time in the observed history. Though the winter 1996/1997 was also very cold in March–April, the temperatures were higher in December–February, and, therefore, chlorine activation was moderate and ozone loss was average with about 1.2 ppmv at 475–550 K or 42 DU at 350–550 K, as diagnosed from the model simulations and measurements.
25
Chauhan, S., M. Höpfner, G. P. Stiller, T. von Clarmann, B. Funke, N. Glatthor, U. Grabowski, et al. "MIPAS reduced spectral resolution UTLS-1 mode measurements of temperature, O<sub>3</sub>, HNO<sub>3</sub>, N<sub>2</sub>O, H<sub>2</sub>O and relative humidity over ice: retrievals and comparison to MLS." Atmospheric Measurement Techniques 2, no. 2 (July 21, 2009): 337–53. http://dx.doi.org/10.5194/amt-2-337-2009.
Анотація:
Abstract. During several periods since 2005 the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat has performed observations dedicated to the region of the upper troposphere/lower stratosphere (UTLS). For the duration of November/December 2005 global distributions of temperature and several trace gases from MIPAS UTLS-1 mode measurements have been retrieved using the IMK/IAA (Institut für Meteorologie und Klimaforschung/Instituto de Astrofísica de Andalucía) scientific processor. In the UTLS region a vertical resolution of 3 km for temperaure, 3 to 4 km for H2O, 2.5 to 3 km for O3, 3.5 km for HNO3 and 3.5 to 2.5 km for N2O has been achieved. The retrieved temperature, H2O, O3, HNO3, N2O, and relative humidity over ice are intercompared with the Microwave Limb Sounder (MLS/Aura) v2.2 data in the pressure range 316 to 0.68 hPa, 316 to 0.68 hPa, 215 to 0.68 hPa, 215 to 3.16 hPa, 100 to 1 hPa and 316 to 10 hPa, respectively. In general, MIPAS and MLS temperatures are biased within ±4 K over the whole pressure and latitude range. Systematic, latitude-independent differences of −2 to −4 K (MIPAS-MLS) at 121 hPa are explained by previously observed biases in the MLS v2.2 temperature retrievals. Temperature differences of −4 K up to 12 K above 10.0 hPa are present both in MIPAS and MLS with respect to ECMWF (European Centre for Medium-Range Weather Forecasts) and are likely due to deficiencies of the ECMWF analysis data. MIPAS and MLS stratospheric volume mixing ratios (vmr) of H2O are biased within ±1 ppmv, with indication of oscillations between 146 and 26 hPa in the MLS dataset. Tropical upper tropospheric values of relative humidity over ice measured by the two instruments differ by ±20% in the pressure range ~146 to 68 hPa. These differences are mainly caused by the MLS temperature biases. Ozone mixing ratios agree within 0.5 ppmv (10 to 20%) between 68 and 14 hPa. At pressures smaller than 10 hPa, MIPAS O3 vmr are higher than MLS by an average of 0.5 ppmv (10%). General agreement between MIPAS and MLS HNO3 is within the range of −1.0 (−10%) to 1.0 ppbv (20%). MIPAS HNO3 is 1.0 ppbv (10%) higher compared to MLS between 46 hPa and 10 hPa over the Northern Hemisphere. Over the tropics at 31.6 hPa MLS shows a low bias of more than 1 ppbv (>50%). In general, MIPAS and MLS N2O vmr agree within 20 to 40 ppbv (20 to 40%). Differences in the range between 100 to 21 hPa are attributed to a known 20% positive bias in MIPAS N2O data.
26
Bocos-Bintintan, Victor, and Ileana Andreea Ratiu. "Fast Sensing of Hydrogen Cyanide (HCN) Vapors Using a Hand-Held Ion Mobility Spectrometer with Nonradioactive Ionization Source." Sensors 21, no. 15 (July 26, 2021): 5045. http://dx.doi.org/10.3390/s21155045.
Анотація:
Sensitive real-time detection of vapors produced by toxic industrial chemicals (TICs) always represents a stringent priority. Hydrogen cyanide (HCN) is definitely a TIC, being widely used in various industries and as an insecticide; it is a reactive, very flammable, and highly toxic compound that affects the central nervous system, cardiovascular system, eyes, nose, throat, and also has systemic effects. Moreover, HCN is considered a blood chemical warfare agent. This study was focused toward quick detection and quantification of HCN in air using time-of-flight ion mobility spectrometry (ToF IMS). Results obtained clearly indicate that IMS can rapidly detect HCN at sub-ppmv levels in air. Ion mobility spectrometric response was obtained in the negative ion mode and presented one single distinct product ion, at reduced ion mobility K0 of 2.38 cm2 V−1 s−1. Our study demonstrated that by using a miniaturized commercial IMS system with nonradioactive ionization source model LCD-3.2E (Smiths Detection Ltd., London, UK), one can easily measure HCN at concentrations of 0.1 ppmv (0.11 mg m−3) in negative ion mode, which is far below the OSHA PEL-TWA value of 10 ppmv. Measurement range was from 0.1 to 10 ppmv and the estimated limit of detection LoD was ca. 20 ppbv (0.02 mg m−3).
27
Fiorucci, I., G. Muscari, L. Froidevaux, and M. L. Santee. "Ground-based stratospheric O<sub>3</sub> and HNO<sub>3</sub> measurements at Thule, Greenland: an intercomparison with Aura MLS observations." Atmospheric Measurement Techniques 6, no. 9 (September 23, 2013): 2441–53. http://dx.doi.org/10.5194/amt-6-2441-2013.
Анотація:
Abstract. In response to the need for improving our understanding of the evolution and the interannual variability of the winter Arctic stratosphere, in January 2009 a Ground-Based Millimeter-wave Spectrometer (GBMS) was installed at the Network for the Detection of Atmospheric Composition Change (NDACC) site in Thule (76.5° N, 68.8° W), Greenland. In this work, stratospheric GBMS O3 and HNO3 vertical profiles obtained from Thule during the winters 2010 (HNO3 only), 2011 and 2012 are characterized and intercompared with co-located measurements of the Aura Microwave Limb Sounder (MLS) experiment. Using a recently developed algorithm based on Optimal Estimation, we find that the GBMS O3 retrievals show good sensitivity (> 80%) to atmospheric variations between ~ 17 and ~ 50 km, where their 1σ uncertainty is estimated to be the larger of ~ 11% or 0.2 ppmv. Similarly, HNO3 profiles can be considered for scientific use between ~ 17 and ~ 45 km altitude, with a 1σ uncertainty that amounts to the larger of 15% or 0.2 ppbv. Comparisons with Aura MLS version 3.3 observations show that, on average, GBMS O3 mixing ratios are biased negatively with respect to MLS throughout the stratosphere, with differences ranging between ~ 0.3 ppmv (8%) and 0.9 ppmv (18%) in the 17–50 km vertical range. GBMS HNO3 values display instead a positive bias with respect to MLS up to 26 km, reaching a maximum of ~ 1 ppbv (10%) near the mixing ratio profile peak. O3 and HNO3 values from the two datasets prove to be well correlated at all altitudes, although their correlations worsen at the lower end of the altitude ranges considered. Column contents of GBMS and MLS O3 (from 20 km upwards) and HNO3 (from 17 km upwards) correlate very well and indicate that GBMS measurements can provide valuable estimates of column interannual and seasonal variations for these compounds.
28
Fiorucci, I., G. Muscari, L. Froidevaux, and M. L. Santee. "Ground-based stratospheric O<sub>3</sub> and HNO<sub>3</sub> measurements at Thule, Greenland: an intercomparison with Aura MLS observations." Atmospheric Measurement Techniques Discussions 6, no. 2 (March 25, 2013): 2979–3011. http://dx.doi.org/10.5194/amtd-6-2979-2013.
Анотація:
Abstract. In response to the need for improving our understanding of the evolution and the interannual variability of the winter Arctic stratosphere, in January 2009 a ground-based millimeter-wave spectrometer (GBMS) was installed at the Network for the Detection of Atmospheric Composition Change (NDACC) site in Thule (76.5° N, 68.8° W), Greenland. In this work, stratospheric GBMS O3 and HNO3 vertical profiles obtained from Thule during winters 2010 (HNO3 only), 2011 and 2012 are characterized and intercompared with co-located Aura MLS measurements. Using a recently developed algorithm based on Optimal Estimation, we find that the GBMS O3 retrievals show good sensitivity (> 80%) to atmospheric variations between ~ 17 and ~ 50 km, where their 1σ uncertainty is estimated to be the larger of ~ 11% or 0.2 ppmv. Similarly, HNO3 profiles can be considered for scientific use between ~ 17 and ~ 45 km altitude, with a 1σ uncertainty that amounts to the larger of 15% or 0.2 ppbv. Comparisons with Aura MLS version 3.3 observations show that, on average, GBMS O3 mixing ratios are biased low with respect to MLS throughout the stratosphere, with differences ranging between ~ 0.3 ppmv (8%) and 0.9 ppmv (18%) in the 17–50 km vertical range. GBMS HNO3 values display instead a high bias with respect to MLS up to 26 km, reaching a maximum of ~ 1 ppbv (10%) near the mixing ratio profile peak. O3 and HNO3 values from the two data sets prove to be well correlated at all altitudes, although their correlations worsen at the lower end of the altitude ranges considered. Column contents of GBMS and MLS O3 (from 20 km upwards) and HNO3 (from 17 km upwards) correlate very well and indicate that GBMS measurements can provide valuable estimates of column interannual and seasonal variations for these compounds.
29
Raffalski, U., G. Hochschild, G. Kopp, and J. Urban. "Evolution of stratospheric ozone during winter 2002/2003 as observed by a ground-based millimetre wave radiometer at Kiruna, Sweden." Atmospheric Chemistry and Physics Discussions 5, no. 1 (January 11, 2005): 131–54. http://dx.doi.org/10.5194/acpd-5-131-2005.
Анотація:
Abstract. We present ozone measurements of the millimetre wave radiometer installed at the Swedish Institute of Space Physics (Institutet för rymdfysik, IRF) in Kiruna (67.8° N, 20.4° E, 420 m a.s.l.). Nearly continuous operation in the winter of 2002/2003 allow us to give an overview of ozone evolution in the stratosphere between 15 and 55 km. In this study we present a detailed analysis of the Arctic winter 2002/2003. By means of a methodology using equivalent latitudes we investigate the meteorological processes in the stratosphere during the entire winter/spring period. During the course of the winter strong mixing into the vortex took place in the middle and upper stratosphere as a result of three minor and one major warming event, but no evidence was found for significant mixing in the lower stratosphere. Ozone depletion in the lower stratosphere during this winter was estimated by measurements on those days when Kiruna was well inside the Arctic polar vortex. The days were carefully chosen using a definition of the vortex edge based on equivalent latitudes. At the 475 K isentropic level a cumulative ozone loss of about 0.5 ppmv was found starting in January and lasting until mid-March. The early ozone loss is probably a result of the very cold temperatures in the lower stratosphere in December and the geographical extension of the vortex to lower latitudes where solar irradiation started photochemical ozone loss in the pre-processed air. In order to correct for dynamical effects of the ozone variation due to diabatic subsidence of air masses inside the vortex, we used N2O measurements from the Odin satellite for the same time period. The derived ozone loss in the lower stratosphere between mid-December and mid-March varies between 1.1±0.1 ppmv on the 150 ppbv N2O isopleth and 1.7±0.1 ppmv on the 50 ppbv N2O isopleth.
30
Raffalski, U., G. Hochschild, G. Kopp, and J. Urban. "Evolution of stratospheric ozone during winter 2002/2003 as observed by a ground-based millimetre wave radiometer at Kiruna, Sweden." Atmospheric Chemistry and Physics 5, no. 5 (June 10, 2005): 1399–407. http://dx.doi.org/10.5194/acp-5-1399-2005.
Анотація:
Abstract. We present ozone measurements from the millimetre wave radiometer installed at the Swedish Institute of Space Physics (Institutet för rymdfysik, IRF) in Kiruna (67.8° N, 20.4° E, 420 m asl). Nearly continuous operation in the winter of 2002/2003 allows us to give an overview of ozone evolution in the stratosphere between 15 and 55 km. In this study we present a detailed analysis of the Arctic winter 2002/2003. By means of a methodology using equivalent latitudes we investigate the meteorological processes in the stratosphere during the entire winter/spring period. During the course of the winter strong mixing into the vortex took place in the middle and upper stratosphere as a result of three minor and one major warming event, but no evidence was found for significant mixing in the lower stratosphere. Ozone depletion in the lower stratosphere during this winter was estimated by measurements on those days when Kiruna was well inside the Arctic polar vortex. The days were carefully chosen using a definition of the vortex edge based on equivalent latitudes. At the 475 K isentropic level a cumulative ozone loss of about 0.5 ppmv was found starting in January and lasting until mid-March. The early ozone loss is probably a result of the very cold temperatures in the lower stratosphere in December and the geographical extension of the vortex to lower latitudes where solar irradiation started photochemical ozone loss in the pre-processed air. In order to correct for dynamic effects of the ozone variation due to diabatic subsidence of air masses inside the vortex, we used N2O measurements from the Odin satellite for the same time period. The derived ozone loss in the lower stratosphere between mid-December and mid-March varies between 1.1±0.1 ppmv on the 150 ppbv N2O isopleth and 1.7±0.1 ppmv on the 50 ppbv N2O isopleth.
31
Ma, J. Z., W. Wang, Y. Chen, H. J. Liu, P. Yan, G. A. Ding, M. L. Wang, J. Sun, and J. Lelieveld. "The IPAC-NC field campaign: a pollution and oxidization pool in the lower atmosphere over Huabei, China." Atmospheric Chemistry and Physics 12, no. 9 (May 3, 2012): 3883–908. http://dx.doi.org/10.5194/acp-12-3883-2012.
Анотація:
Abstract. In the past decades, regional air pollution characterized by photochemical smog and grey haze-fog has become a severe environmental problem in China. To investigate this, a field measurement campaign was performed in the Huabei region, located between 32–42° N latitude in eastern China, during the period 2 April–16 May 2006 as part of the project "Influence of Pollution on Aerosols and Cloud Microphysics in North China" (IPAC-NC). It appeared that strong pollution emissions from urban and industrial centers tend to accumulate in the lower atmosphere over the central area of Huabei. We observed widespread, very high SO2 mixing ratios, about 20–40 ppbv at 0.5–1.5 km altitude and 10–30 ppbv at 1.5–3.0 km altitude. Average CO mixing ratios were 0.65–0.7 ppmv at 0.5–1.5 km altitude, and very high CO around 1 ppmv was observed during some flights, and even higher levels at the surface. We find the high pollution concentrations to be associated with enhanced levels of OH and HO2 radicals, calculated with a chemical box model constrained by the measurements. In the upper part of the boundary layer and in the lower free troposphere, high CO and SO2 compete with relatively less NO2 in reacting with OH, being efficiently recycled through HO2, preventing a net loss of HOx radicals. In addition to reactive hydrocarbons and CO, the oxidation of SO2 causes significant ozone production over Huabei (up to ~13% or 2.0 ppbv h−1 at 0.8 km altitude). Our results indicate that the lower atmosphere over Huabei is not only strongly polluted but also acts as an oxidation pool, with pollutants undergoing very active photochemistry over this part of China.
32
Egbe, Daniel Ayuk Mbi, Carsten Peter Roll, Eckhard Birckner, Ulrich-Walter Grummt, Regina Stockmann, and Elisabeth Klemm. "Side Chain Effects in Hybrid PPV/PPE Polymers." Macromolecules 35, no. 10 (May 2002): 3825–37. http://dx.doi.org/10.1021/ma012195g.
33
Ricaud, P., B. Barret, J. L. Attié, E. Motte, E. Le Flochmoën, H. Teyssèdre, V. H. Peuch, N. Livesey, A. Lambert, and J. P. Pommereau. "Impact of land convection on troposphere-stratosphere exchange in the tropics." Atmospheric Chemistry and Physics 7, no. 21 (November 15, 2007): 5639–57. http://dx.doi.org/10.5194/acp-7-5639-2007.
Анотація:
Abstract. The mechanism of troposphere-stratosphere exchange in the tropics was investigated from space-borne observations of the horizontal distributions of tropospheric-origin long-lived species, nitrous oxide (N2O), methane (CH4) and carbon monoxide (CO), from 150 to 70 hPa in March-April-May by the ODIN/Sub-Millimeter Radiometer (SMR), the Upper Atmosphere Research Satellite (UARS)/Halogen Occultation Experiment (HALOE) and the TERRA/Measurements Of Pollution In The Troposphere (MOPITT) instruments in 2002–2004, completed by recent observations of the AURA/Microwave Limb Sounder (MLS) instrument during the same season in 2005. The vertical resolution of the satellite measurements ranges from 2 to 4 km. The analysis has been performed on isentropic surfaces: 400 K (lower stratosphere) for all the species and 360 K (upper troposphere) only for CO. At 400 K (and 360 K for CO), all gases show significant longitudinal variations with peak-to-trough values of ~5–11 ppbv for N2O, 0.07–0.13 ppmv for CH4, and ~10 ppbv for CO (~40 ppbv at 360 K). The maximum amounts are primarily located over Africa and, depending on the species, secondary more or less pronounced maxima are reported above northern South America and South-East Asia. The lower stratosphere over the Western Pacific deep convective region where the outgoing longwave radiation is the lowest, the tropopause the highest and the coldest, appears as a region of minimum concentration of tropospheric trace species. The possible impact on trace gas concentration at the tropopause of the inhomogeneous distribution and intensity of the sources, mostly continental, of the horizontal and vertical transports in the troposphere, and of cross-tropopause transport was explored with the MOCAGE Chemistry Transport Model. In the simulations, significant longitudinal variations were found on the medium-lived CO (2-month lifetime) with peak-to-trough value of ~20 ppbv at 360 K and ~10 ppbv at 400 K, slightly weaker than observations. However, the CH4 (8–10 year lifetime) and N2O (130-year lifetime) longitudinal variations are significantly weaker than observed: peak-to-trough values of ~0.02 ppmv for CH4 and 1–2 ppbv for N2O at 400 K. The large longitudinal contrast of N2O and CH4 concentrations reported by the space-borne instruments at the tropopause and in the lower stratosphere not captured by the model thus requires another explanation. The suggestion is of strong overshooting over land convective regions, particularly Africa, very consistent with the space-borne Tropical Rainfall Measuring Mission (TRMM) radar maximum overshooting features over the same region during the same season. Compared to observations, the MOCAGE model forced by ECMWF analyses is found to ignore these fast local uplifts, but to overestimate the average uniform vertical transport in the UTLS at all longitudes in the tropics.
34
Fedyanin, V. V., and I. S. Osad'ko. "Photon statistics in blinking fluorescence of single PPV-PPyV molecule." Journal of Chemical Physics 135, no. 12 (September 28, 2011): 125103. http://dx.doi.org/10.1063/1.3640891.
35
Ma, J. Z., W. Wang, Y. Chen, H. J. Liu, P. Yan, G. A. Ding, M. L. Wang, and J. Lelieveld. "The IPAC-NC field campaign: a pollution and oxidization pool in the lower atmosphere over Huabei, China." Atmospheric Chemistry and Physics Discussions 11, no. 10 (October 12, 2011): 27701–62. http://dx.doi.org/10.5194/acpd-11-27701-2011.
Анотація:
Abstract. In the past decades, regional air pollution characterized by photochemical smog and grey haze-fog has become a severe environmental problem in China. To investigate this, a field measurement campaign was performed in the Huabei region, located between 32°–42° N latitude in Eastern China, during the period 2 April–16 May 2006 as part of the project "Influence of Pollution on Aerosols and Cloud Microphysics in North China" (IPAC-NC). It was found that strong pollution emissions from urban and industrial centers accumulate in the lower atmosphere over the core area of Huabei. We observed widespread, very high SO2 mixing ratios, about 20–40 ppbv at 0.5–1.5 km altitude and 10–30 ppbv at 1.5–3.0 km altitude. Average CO mixing ratios were 0.65–0.7 ppmv at 0.5–1.5 km altitude, and very high CO around 1 ppmv was observed during some flights, and even higher levels at the surface. The high pollution concentrations were associated with enhanced levels of OH and HO2 radicals, calculated with a chemical box model constrained by the measurements. The maximum OH concentration was 6.9 × 106 molecules cm−3 (~0.29 pptv) at an altitude of ~1 km, remarkably higher than 5.4 × 106 molecules cm−3 (~0.22 pptv) at the surface. In the upper part of the boundary layer and in the lower free troposphere, high CO and SO2 competed with relatively less NO2 in reacting with OH, being efficiently recycled through HO2, preventing a net loss of HOx radicals. In addition to reactive hydrocarbons and CO, the oxidation of SO2 caused significant ozone production over Huabei (up to ~13% or 2.0 ppbv h−1 at ~0.8 km). The enhanced OH increased the formation of condensable species by the oxidation of volatile precursor gases, adding to the high loadings of mineral dust particles. Our results indicate that the lower atmosphere over Huabei is not only strongly polluted but also acts as an oxidation pool over Eastern China.
36
Remsberg, Ellis, V. Lynn Harvey, Arlin Krueger, Larry Gordley, John C. Gille, and James M. Russell III. "Technical note: LIMS observations of lower stratospheric ozone in the southern polar springtime of 1978." Atmospheric Chemistry and Physics 20, no. 6 (March 26, 2020): 3663–68. http://dx.doi.org/10.5194/acp-20-3663-2020.
Анотація:
Abstract. The Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) instrument operated from 25 October 1978 through 28 May 1979. This note focuses on its Version 6 (V6) data and indications of ozone loss in the lower stratosphere of the Southern Hemisphere subpolar region during the last week of October 1978. We provide profiles and maps that show V6 ozone values of only 2 to 3 ppmv at 46 hPa within the edge of the polar vortex near 60∘ S from late October through mid-November 1978. There are also low values of V6 nitric acid (∼3 to 6 ppbv) and nitrogen dioxide (< 1 ppbv) at the same locations, indicating that conditions were suitable for a chemical loss of Antarctic ozone some weeks earlier. These “first light” LIMS observations provide the earliest space-based view of conditions within the lower stratospheric ozone layer of the southern polar region in springtime.
37
Buchwitz, M., R. de Beek, J. P. Burrows, H. Bovensmann, T. Warneke, J. Notholt, J. F. Meirink, et al. "Atmospheric methane and carbon dioxide from SCIAMACHY satellite data: initial comparison with chemistry and transport models." Atmospheric Chemistry and Physics 5, no. 4 (March 21, 2005): 941–62. http://dx.doi.org/10.5194/acp-5-941-2005.
Анотація:
Abstract. The remote sensing of the atmospheric greenhouse gases methane (CH4) and carbon dioxide (CO2) in the troposphere from instrumentation aboard satellites is a new area of research. In this manuscript, results obtained from observations of the up-welling radiation in the near-infrared by SCIAMACHY on board ENVISAT are presented. Vertical columns of CH4, CO2 and oxygen (O2) have been retrieved and the (air or) O2-normalised CH4 and CO2 column amounts, the dry air column averaged mixing ratios XCH4 and XCO2 derived. In this manuscript the first results, obtained by using the version 0.4 of the Weighting Function Modified (WFM) DOAS retrieval algorithm applied to SCIAMACHY data, are described and compared with global models. For the set of individual cloud free measurements over land the standard deviation of the difference with respect to the models is in the range ~100–200 ppbv (5–10%) for XCH4 and ~14–32 ppmv (4–9%) for XCO2. The inter-hemispheric difference of the methane mixing ratio, as determined from single day data, is in the range 30–110 ppbv and in reasonable agreement with the corresponding model data (48–71 ppbv). The weak inter-hemispheric difference of the CO2 mixing ratio can also be detected with single day data. The spatiotemporal pattern of the measured and the modelled XCO2 are in reasonable agreement. However, the amplitude of the difference between the maximum and the minimum for SCIAMACHY XCO2 is about ±20 ppmv which is about a factor of four larger than the variability of the model data which is about ±5 ppmv. More studies are needed to explain the observed differences. The XCO2 model field shows low CO2 concentrations beginning of January 2003 over a spatially extended CO2 sink region located in southern tropical/sub-tropical Africa. The SCIAMACHY data also show low CO2 mixing ratios over this area. According to the model the sink region becomes a source region about six months later and exhibits higher mixing ratios. The SCIAMACHY and the model data over this region show a similar time dependence over the period from January to October 2003. These results indicate that for the first time a regional CO2 surface source/sink region has been detected by measurements from space. The interpretation of the SCIAMACHY CO2 and CH4 measurements is difficult, e.g., because the error analysis of the currently implemented retrieval algorithm indicates that the retrieval errors are on the same order as the small greenhouse gas mixing ratio changes that are to be detected.
38
Hoppe, H., N. S. Sariciftci, D. A. M. Egbe, D. Mühlbacher, and M. Koppe. "Plastic Solar Cells Based on Novel PPE-PPV-Copolymers." Molecular Crystals and Liquid Crystals 426, no. 1 (March 2005): 255–63. http://dx.doi.org/10.1080/15421400590891227.
39
Wang, Yiqing, James N. Wilson, Mark D. Smith, and Uwe H. F. Bunz. "TEMPO-Substituted PPEs: Polystyrene-PPE Graft Copolymers and Double Graft Copolymers." Macromolecules 37, no. 26 (December 2004): 9701–8. http://dx.doi.org/10.1021/ma048308o.
40
Zarzana, Kyle J., Vanessa Selimovic, Abigail R. Koss, Kanako Sekimoto, Matthew M. Coggon, Bin Yuan, William P. Dubé, et al. "Primary emissions of glyoxal and methylglyoxal from laboratory measurements of open biomass burning." Atmospheric Chemistry and Physics 18, no. 20 (October 26, 2018): 15451–70. http://dx.doi.org/10.5194/acp-18-15451-2018.
Анотація:
Abstract. We report the emissions of glyoxal and methylglyoxal from the open burning of biomass during the NOAA-led 2016 FIREX intensive at the Fire Sciences Laboratory in Missoula, MT. Both compounds were measured using cavity-enhanced spectroscopy, which is both more sensitive and more selective than methods previously used to determine emissions of these two compounds. A total of 75 burns were conducted, using 33 different fuels in 8 different categories, providing a far more comprehensive dataset for emissions than was previously available. Measurements of methylglyoxal using our instrument suffer from spectral interferences from several other species, and the values reported here are likely underestimates, possibly by as much as 70 %. Methylglyoxal emissions were 2–3 times higher than glyoxal emissions on a molar basis, in contrast to previous studies that report methylglyoxal emissions lower than glyoxal emissions. Methylglyoxal emission ratios for all fuels averaged 3.6±2.4 ppbv methylglyoxal (ppmv CO)−1, while emission factors averaged 0.66±0.50 g methylglyoxal (kg fuel burned)−1. Primary emissions of glyoxal from biomass burning were much lower than previous laboratory measurements but consistent with recent measurements from aircraft. Glyoxal emission ratios for all fuels averaged 1.4±0.7 ppbv glyoxal (ppmv CO)−1, while emission factors averaged 0.20±0.12 g glyoxal (kg fuel burned)−1, values that are at least a factor of 4 lower than assumed in previous estimates of the global glyoxal budget. While there was significant variability in the glyoxal emission ratios and factors between the different fuel groups, glyoxal and formaldehyde were highly correlated during the course of any given fire, and the ratio of glyoxal to formaldehyde, RGF, was consistent across many different fuel types, with an average value of 0.068±0.018. While RGF values for fresh emissions were consistent across many fuel types, further work is required to determine how this value changes as the emissions age.
41
Konkin, A. L., S. Sensfuss, H. K. Roth, G. Nazmutdinova, M. Schroedner, M. Al-Ibrahim, and D. A. M. Egbe. "LESR study on PPV–PPE/PCBM composites for organic photovoltaics." Synthetic Metals 148, no. 2 (January 2005): 199–204. http://dx.doi.org/10.1016/j.synthmet.2004.09.023.
42
Nara, Hideki, Hiroshi Tanimoto, Yukihiro Nojiri, Hitoshi Mukai, Jiye Zeng, Yasunori Tohjima, and Toshinobu Machida. "CO emissions from biomass burning in South-east Asia in the 2006 El Niño year: shipboard and AIRS satellite observations." Environmental Chemistry 8, no. 2 (2011): 213. http://dx.doi.org/10.1071/en10113.
Анотація:
Environmental contextAtmospheric carbon monoxide greatly affects the abundance of environmentally important gases, including methane, hydrochlorofluorocarbons and tropospheric ozone. We present evidence for episodes of CO pollution over the tropical Pacific Ocean resulting from intensive biomass burning in South-east Asia and Northern Australia during the 2006 El Niño year. We discuss the locations of the CO emissions and their long-range transport. AbstractBiomass burning is often associated with climate oscillations. For example, biomass burning in South-east Asia is strongly linked to El Niño–southern oscillation activity. During October and November of the 2006 El Niño year, a substantial increase in CO mixing ratios was detected over the Western tropical Pacific Ocean by shipboard observations routinely operated between Japan and Australia and New Zealand. Combining in-situ measurements, satellite observations, and an air trajectory model simulation, two high CO episodes were identified originating from biomass burning in Borneo, Sumatra, New Guinea, and Northern Australia. Between 15°N and the Equator, marked CO enhancements were encountered associated with a significant correlation between CO and CO2 and between CO and O3. The ΔCO/ΔCO2 ratio observed in the fire plume was considerably high (171 ppbv ppmv–1), suggesting substantial contributions from peat soil burning in Indonesia. In contrast, the ΔO3/ΔCO ratio was only 0.05 ppbv ppbv–1, indicating that net photochemical production of O3 in the plume was negligible during long-range transport in the lower troposphere over the Western tropical North Pacific.
43
Susarova, Diana K., Ekaterina A. Khakina, Pavel A. Troshin, Andrey E. Goryachev, N. Serdar Sariciftci, Vladimir F. Razumov, and Daniel A. M. Egbe. "Photovoltaic performance of PPE-PPV copolymers: effect of the fullerene component." J. Mater. Chem. 21, no. 7 (2011): 2356–61. http://dx.doi.org/10.1039/c0jm02681f.
44
Egbe, Daniel A. M., Hartwig Tillmann, Eckhard Birckner, and Elisabeth Klemm. "Synthesis and Properties of Novel Well-Defined Alternating PPE/PPV Copolymers." Macromolecular Chemistry and Physics 202, no. 13 (September 1, 2001): 2712–26. http://dx.doi.org/10.1002/1521-3935(20010901)202:13<2712::aid-macp2712>3.0.co;2-g.
45
Bocos-Bintintan, Victor, and Ileana Andreea Ratiu. "Hunting for Toxic Industrial Chemicals: Real-Time Detection of Carbon Disulfide Traces by Means of Ion Mobility Spectrometry." Toxics 8, no. 4 (December 14, 2020): 121. http://dx.doi.org/10.3390/toxics8040121.
Анотація:
Sensitive real-time detection of vapors produced by toxic industrial chemicals (TICs) represents a stringent priority nowadays. Carbon disulfide (CS2) is such a chemical, being widely used in manufacturing synthetic textile fibers and as a solvent. CS2 is simultaneously a very reactive, highly flammable, irritant, corrosive, and highly toxic compound, affecting the central nervous system, cardiovascular system, eyes, kidneys, liver, skin, and reproductive system. This study was directed towards quick detection and quantification of CS2 in air, using time-of-flight ion mobility spectrometry (IMS); photoionization detection (PID) was also used as confirmatory technique. Results obtained indicated that IMS can detect CS2 at trace levels in air. The ion mobility spectrometric response was in the negative ion mode and presented one product ion, at a reduced ion mobility (K0) of 2.25 cm2 V−1 s−1. Our study demonstrated that by using a portable, commercial IMS system (model Mini IMS, I.U.T. GmbH Berlin Germany) one can easily measure CS2 at concentrations of 0.1 ppmv (0.3 mg m−3) in the negative ion mode, which is below the lowest threshold value of 1 ppmv given for industrial hygiene. A limit of detection (LOD) of ca. 30 ppbv (0.1 mg m−3) was also estimated.
46
Vaschetto, Mariana E., Andrew P. Monkman, and Michael Springborg. "First-principles studies of some conducting polymers: PPP, PPy, PPV, PPyV, and PANI." Journal of Molecular Structure: THEOCHEM 468, no. 3 (August 1999): 181–91. http://dx.doi.org/10.1016/s0166-1280(98)00565-x.
47
Talbot, R., H. Mao, E. Scheuer, J. Dibb, M. Avery, E. Browell, G. Sachse, et al. "Factors influencing the large-scale distribution of Hg° in the Mexico City area and over the North Pacific." Atmospheric Chemistry and Physics Discussions 7, no. 6 (November 2, 2007): 15533–63. http://dx.doi.org/10.5194/acpd-7-15533-2007.
Анотація:
Abstract. Gas-phase elemental mercury (Hg°) was measured aboard the NASA DC-8 aircraft during the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in spring 2006. Flights were conducted around Mexico City and on two subsequent deployments over the North Pacific based out of Honolulu, Hawaii and Anchorage, Alaska. Data obtained from 0.15–12 km altitude showed that Hg° exhibited a relatively constant vertical profile centered around 100 ppqv. Highly concentrated pollution plumes emanating from the Mexico City urban agglomeration revealed that mixing ratios of Hg° as large as 500 ppqv were related to combustion tracers such as CO, but not SO2 which is presumably released locally from coal burning, refineries, and volcanoes. Our analysis of Mexico City plumes indicated that widespread multi-source urban/industrial emissions may have a more important influence on Hg° than specific point sources. Over the Pacific, correlations with CO, CO2, CH4, and C2Cl4 were diffuse overall, but recognizable on flights out of Anchorage and Honolulu. In distinct plumes originating from the Asian continent the Hg°- CO relationship yielded an average value of ~0.56 ppqv/ppbv, in good agreement with previous findings. A prominent feature of the INTEX-B dataset was frequent total depletion of Hg° in the upper troposphere when stratospherically influenced air was encountered. Ozone data obtained with the differential absorption lidar (DIAL) showed that the stratospheric impact on the tropospheric column was a common and pervasive feature on all flights out of Honolulu and Anchorage. We propose that this is likely a major factor driving large-scale seasonality in Hg° mixing ratios, especially at mid-latitudes, and an important process that should be incorporated into global chemical transport models.
48
Talbot, R., H. Mao, E. Scheuer, J. Dibb, M. Avery, E. Browell, G. Sachse, et al. "Factors influencing the large-scale distribution of Hg° in the Mexico City area and over the North Pacific." Atmospheric Chemistry and Physics 8, no. 7 (April 11, 2008): 2103–14. http://dx.doi.org/10.5194/acp-8-2103-2008.
Анотація:
Abstract. Gas-phase elemental mercury (Hg°) was measured aboard the NASA DC-8 aircraft during the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in spring 2006. Flights were conducted around Mexico City and on two subsequent deployments over the North Pacific based out of Honolulu, Hawaii and Anchorage, Alaska. Data obtained from 0.15–12 km altitude showed that Hg° exhibited a relatively constant vertical profile centered around 100 ppqv. Highly concentrated pollution plumes emanating from the Mexico City urban agglomeration revealed that mixing ratios of Hg° as large as 500 ppqv were related to combustion tracers such as CO, but not SO2 which is presumably released locally from coal burning, refineries, and volcanoes. Our analysis of Mexico City plumes indicated that widespread multi-source urban/industrial emissions may have a more important influence on Hg° than specific point sources. Over the Pacific, correlations with CO, CO2, CH4, and C2Cl4 were diffuse overall, but recognizable on flights out of Anchorage and Honolulu. In distinct plumes originating from the Asian continent the Hg°- CO relationship yielded an average value of ~0.56 ppqv/ppbv, in good agreement with previous findings. A prominent feature of the INTEX-B dataset was frequent total depletion of Hg° in the upper troposphere when stratospherically influenced air was encountered. Ozone data obtained with the differential absorption lidar (DIAL) showed that the stratospheric impact on the tropospheric column was a common and pervasive feature on all flights out of Honolulu and Anchorage. We propose that this is likely a major factor driving large-scale seasonality in Hg° mixing ratios, especially at mid-latitudes, and an important process that should be incorporated into global chemical transport models.
49
Roy, Raina, Pankaj Kumar, Jayanarayanan Kuttippurath, and Franck Lefevre. "Chemical ozone loss and chlorine activation in the Antarctic winters of 2013–2020." Atmospheric Chemistry and Physics 24, no. 4 (February 23, 2024): 2377–86. http://dx.doi.org/10.5194/acp-24-2377-2024.
Анотація:
Abstract. The annual formation of an ozone hole in the austral spring has regional and global climate implications. The Antarctic ozone hole has already changed the precipitation, temperature and atmospheric circulation patterns, and thus the surface climate of many regions in the Southern Hemisphere (SH). Therefore, the study of ozone loss variability is important to assess its consequential effects on the climate and public health. Our study uses satellite observations from the Microwave Limb Sounder on Aura and the passive-tracer method to quantify the ozone loss for the past 8 years (2013–2020) in the Antarctic. We observe the highest ozone loss (about 3.5 ppmv) in 2020, owing to the high chlorine activation (about 2.2 ppbv), steady polar vortex, and huge expanses of polar stratospheric clouds (PSCs) (12.6×106 km2) in the winter. The spring of 2019 also showed a high ozone loss, although the year had a rare minor warming in mid-September. The chlorine activation in 2015 (1.9 ppbv) was the weakest, and the wave forcing from the lower latitudes was very high in 2017 (up to −60 km s−1). The analysis shows significant interannual variability in the Antarctic ozone as compared to the immediate previous decade (2000–2010). The study helps to understand the role of dynamics and chemistry in the interannual variability of ozone depletion over the years.
50
Buchwitz, M., R. de Beek, J. P. Burrows, H. Bovensmann, T. Warneke, J. Notholt, J. F. Meirink, et al. "Atmospheric methane and carbon dioxide from SCIAMACHY satellite data: initial comparison with chemistry and transport models." Atmospheric Chemistry and Physics Discussions 4, no. 6 (November 5, 2004): 7217–79. http://dx.doi.org/10.5194/acpd-4-7217-2004.
Анотація:
Abstract. The remote sensing of the atmospheric greenhouse gases methane (CH4) and carbon dioxide (CO2) in the troposphere from instrumentation aboard satellites is a new area of research. In this manuscript, results obtained from observations of the up-welling radiation in the near-infrared by SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY), which flies on board ENVISAT, are presented. Vertical columns of CH4, CO2 and oxygen (O2) have been retrieved and the (air or) O2-normalized CH4 and CO2 column amounts, the dry air column averaged mixing ratios XCH4 and XCO2 derived. In this manuscript the first results, obtained by using the version 0.4 of the Weighting Function Modified (WFM) DOAS retrieval algorithm applied to SCIAMACHY data, are described and compared with global models. This is an important step in assessing the quality and information content of the data products derived from SCIAMACHY observations. This study investigates the behaviour of CO2 and CH4 in the period from January to October 2003. The SCIAMACHY greenhouse gas column amounts and their mixing ratios for cloud free scenes over land are shown to be in reasonable agreement with models. Over the ocean, as a result of the lower surface spectral reflectance and resultant low signal to noise with the exception of sun glint conditions, the accuracy of the individual data products is poorer. The measured methane column amounts agree with the model columns within a few percent. The inter-hemispheric difference of the methane mixing ratios, determined from single day cloud free measurements over land, is in the range 30–110 ppbv and in reasonable agreement with the corresponding model data (48–71 ppbv). For the set of individual measurements the standard deviations of the difference with respect to the models are in the range ~100–200 ppbv (5–10%) and ±14.4 ppmv (3.9%) for XCH