Artículos de revistas: "Atmospheric deposits"

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Skarżyńska, K., Ż. Polkowska y J. Namieśnik. "Sampling of Atmospheric Precipitation and Deposits for Analysis of Atmospheric Pollution". Journal of Automated Methods and Management in Chemistry 2006 (2006): 1–19. http://dx.doi.org/10.1155/jammc/2006/26908.

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This paper reviews techniques and equipment for collecting precipitation samples from the atmosphere (fog and cloud water) and from atmospheric deposits (dew, hoarfrost, and rime) that are suitable for the evaluation of atmospheric pollution. It discusses the storage and preparation of samples for analysis and also presents bibliographic information on the concentration ranges of inorganic and organic compounds in the precipitation and atmospheric deposit samples.

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2

Kim, Jiyoung, Chan Hee Lee, Ran Hee Kim y Eun Jeong Shin. "Characterization of White and Black Deposits on the Surface of Korean Stone Cultural Heritages". Microscopy and Microanalysis 19, S5 (agosto de 2013): 167–71. http://dx.doi.org/10.1017/s1431927613012580.

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AbstractWhite and black deposits have been frequently observed on the surface of Korean stone cultural heritages, and they are considered as damage factors in both conservation and esthetic points of view. In order to set up the appropriate conservation remedy, it is important to know their origins, characteristics, and compositions. In this study, optical and scanning electron microscopes (SEMs) equipped with an energy-dispersive spectrometer (EDS) and X-ray diffractometer were employed to determine the white and black deposits. It was found that both deposits consisted mainly of calcium carbonate (calcite) and calcium sulfate (gypsum). The calcite and gypsum were characterized by bladed, rhombohedral, tabular, and amorphous morphologies under a SEM. The black deposit was not only composed of calcite or gypsum, but also accompanied amorphous and irregular matrix. SEM-EDS analysis revealed an abundance of silicon, aluminum, iron, phosphorus, and carbon on the matrix, which were major elements of soil, atmospheric deposits, and organisms. The white deposit, on the other hand, barely contained those coloring substances. These salts and deposited substances were caused by chemical reaction and physical adhesion between rock-forming minerals, lime mortar, sulfur in polluted air environment, soil dust, and microorganisms.

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3

Tripathi, B. D., Anamika Tripathi y Kiran Misra. "Atmospheric dustfall deposits in Varanasi City". Atmospheric Environment. Part B. Urban Atmosphere 25, n.º 1 (enero de 1991): 109–12. http://dx.doi.org/10.1016/0957-1272(91)90044-f.

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4

Dong, Ke, Cheolwoon Woo y Naomichi Yamamoto. "Plant assemblages in atmospheric deposition". Atmospheric Chemistry and Physics 19, n.º 18 (25 de septiembre de 2019): 11969–83. http://dx.doi.org/10.5194/acp-19-11969-2019.

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Abstract. Plants disperse spores, pollen, and fragments into the atmosphere. The emitted plant particles return to the pedosphere by sedimentation (dry deposition) and/or by precipitation (wet deposition) and constitute part of the global cycle of substances. However, little is known regarding the taxonomic diversities and flux densities of plant particles deposited from the atmosphere. Here, plant assemblages were examined in atmospheric deposits collected in Seoul in South Korea. A custom-made automatic sampler was used to collect dry and wet deposition samples for which plant assemblages and quantities were determined using high-throughput sequencing and quantitative polymerase chain reaction (PCR) with universal plant-specific primers targeting the internal transcribed spacer 2 (ITS2) region. Dry deposition was dominant for atmospheric deposition of plant particles (87 %). The remaining 13 % was deposited by precipitation, i.e., wet deposition, via rainout (in-cloud scavenging) and/or washout (below-cloud scavenging). Plant assemblage structures did not differ significantly between dry and wet deposition, indicating a possibility that washout, which is possibly taxon-independent, predominated rainout, which is possibly taxon-dependent, for wet deposition of atmospheric plant particles. A small number of plant genera were detected only in wet deposition, indicating that they might be specifically involved in precipitation through acting as nucleation sites in the atmosphere. Future interannual monitoring will control for the seasonality of atmospheric plant assemblages observed at our sampling site. Future global monitoring is also proposed to investigate geographical differences and investigate whether endemic species are involved in plant-mediated bioprecipitation in regional ecological systems.

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5

Mohamed, Benahmed, Dellal Abdelkader y Hellal Benchaben. "Mobilite Du Plomb Et Du Zinc Issus De Retombees Atmospheriques Dans Le Sol : Cas De La Zone Industrielle De Tiaret, Algerie". European Scientific Journal, ESJ 12, n.º 18 (29 de junio de 2016): 131. http://dx.doi.org/10.19044/esj.2016.v12n18p131.

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Study of heavy metals mobility in soil is a necessary step for making an accurate appraisal and quantitative evaluation of the extent of contamination, indeed, wet and dry atmospheric deposits, plays an important role in the cycle of semi-volatile contaminants (Vinogradova, 2000). Metallurgical industries release heavy metals into the atmosphere, these last, clump together to form fines particles suspended in the air, these metals can be transported by wind via aerosol or aqueous pathway and deposited in the soil. The main aim of this work was to study the mobility and fate of lead and zinc from atmospheric deposits in a contaminated soil from the foundry (ALFET) in the industrial zone of Tiaret (Western Algeria) and to determine the effect of physicochemical parameters of the soil on their mobility in the topsoil. The physicochemical analysis of soil samples have shown that zinc and lead levels contents in the surface layer soil (0-30cm) vary depending on the pH, total limestone (CaCO3). The obtained results clearly show the major effect of soil texture, the fine fraction (clay and sand).

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6

Mason, R. H., C. Chou, C. S. McCluskey, E. J. T. Levin, C. L. Schiller, T. C. J. Hill, J. A. Huffman, P. J. DeMott y A. K. Bertram. "The micro-orifice uniform deposit impactor–droplet freezing technique (MOUDI-DFT) for measuring concentrations of ice nucleating particles as a function of size: improvements and initial validation". Atmospheric Measurement Techniques 8, n.º 6 (15 de junio de 2015): 2449–62. http://dx.doi.org/10.5194/amt-8-2449-2015.

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Abstract. The micro-orifice uniform deposit impactor–droplet freezing technique (MOUDI-DFT) combines particle collection by inertial impaction (via the MOUDI) and a microscope-based immersion freezing apparatus (the DFT) to measure atmospheric concentrations of ice nucleating particles (INPs) as a function of size and temperature. In the first part of this study we improved upon this recently introduced technique. Using optical microscopy, we investigated the non-uniformity of MOUDI aerosol deposits at spatial resolutions of 1, 0.25 mm, and for some stages when necessary 0.10 mm. The results from these measurements show that at a spatial resolution of 1 mm and less, the concentration of particles along the MOUDI aerosol deposits can vary by an order of magnitude or more. Since the total area of a MOUDI aerosol deposit ranges from 425 to 605 mm2 and the area analyzed by the DFT is approximately 1.2 mm2, this non-uniformity needs to be taken into account when using the MOUDI-DFT to determine atmospheric concentrations of INPs. Measurements of the non-uniformity of the MOUDI aerosol deposits were used to select positions on the deposits that had relatively small variations in particle concentration and to build substrate holders for the different MOUDI stages. These substrate holders improve reproducibility by holding the substrate in the same location for each measurement and ensure that DFT analysis is only performed on substrate regions with relatively small variations in particle concentration. In addition, the deposit non-uniformity was used to determine correction factors that take the non-uniformity into account when determining atmospheric concentrations of INPs. In the second part of this study, the MOUDI-DFT utilizing the new substrate holders was compared to the continuous flow diffusion chamber (CFDC) technique of Colorado State University. The intercomparison was done using INP concentrations found by the two instruments during ambient measurements of continental aerosols. Results from two sampling periods were compared, and the INP concentrations determined by the two techniques agreed within experimental uncertainty. The agreement observed here is commensurate with the level of agreement found in other studies where CFDC results were compared to INP concentrations measured with other methods.

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7

Mason, R. H., C. Chou, C. S. McCluskey, E. J. T. Levin, C. L. Schiller, T. C. J. Hill, J. A. Huffman, P. J. DeMott y A. K. Bertram. "The micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT) for measuring concentrations of ice nucleating particles as a function of size: improvements and initial validation". Atmospheric Measurement Techniques Discussions 8, n.º 2 (27 de febrero de 2015): 2223–61. http://dx.doi.org/10.5194/amtd-8-2223-2015.

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Abstract. The micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT) combines particle collection by inertial impaction (via the MOUDI) and a microscope-based immersion freezing apparatus (the DFT) to measure atmospheric concentrations of ice nucleating particles (INPs) as a function of size and temperature. In the first part of this study we improved upon this recently introduced technique. Using optical microscopy, we investigated the non-uniformity of MOUDI aerosol deposits at spatial resolutions of 1, 0.25 mm, and for some stages when necessary 0.10 mm. The results from these measurements show that at a spatial resolution of 1 mm and less, the concentration of particles along the MOUDI aerosol deposit can vary by an order of magnitude or more. Since the total area of a MOUDI aerosol deposit ranges from 425 to 605 mm2 and the area analyzed by the DFT is approximately 1.2 mm2, this non-uniformity needs to be taken into account when using the MOUDI-DFT to determine atmospheric concentrations of INPs. Measurements of the non-uniformity of the MOUDI aerosol deposits were used to select positions on the deposits that had relatively small variations in particle concentration and to build substrate holders for the different MOUDI stages. These substrate holders improve reproducibility by holding the substrate in the same location for each measurement and ensure that DFT analysis is only performed on substrate regions with relatively small variations in particle concentration. In addition, the deposit non-uniformity was used to determine correction factors that take the non-uniformity into account when determining atmospheric concentrations of INPs. In the second part of this study, the MOUDI-DFT utilizing the new substrate holders was compared to the continuous flow diffusion chamber (CFDC) technique of Colorado State University. The intercomparison was done using INP concentrations found by the two instruments during ambient measurements of continental aerosols. Results from two sampling periods were compared and the INP concentrations determined by the two techniques agreed within experimental uncertainty. The agreement observed here is commensurate with the level of agreement found in other studies where CFDC results were compared to INP concentrations measured with other methods.

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8

Barnouin-Jha, Olivier S. y Peter H. Schultz. "Lobateness of impact ejecta deposits from atmospheric interactions". Journal of Geophysical Research: Planets 103, E11 (1 de octubre de 1998): 25739–56. http://dx.doi.org/10.1029/98je02025.

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9

Bekker, A., M. E. Barley, M. L. Fiorentini, O. J. Rouxel, D. Rumble y S. W. Beresford. "Atmospheric Sulfur in Archean Komatiite-Hosted Nickel Deposits". Science 326, n.º 5956 (19 de noviembre de 2009): 1086–89. http://dx.doi.org/10.1126/science.1177742.

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10

Lamare, M. L., J. Lee-Taylor y M. D. King. "The impact of atmospheric mineral aerosol deposition on the albedo of snow and sea ice: are snow and sea ice optical properties more important than mineral aerosol optical properties?" Atmospheric Chemistry and Physics Discussions 15, n.º 16 (27 de agosto de 2015): 23131–72. http://dx.doi.org/10.5194/acpd-15-23131-2015.

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Abstract. Knowledge of the albedo of polar regions is crucial for understanding a range of climatic processes that have an impact on a global scale. Light absorbing impurities in atmospheric aerosols deposited on snow and sea ice by aeolian transport absorb solar radiation, reducing albedo. Here, the effects of five mineral aerosol deposits reducing the albedo of polar snow and sea ice are considered. Calculations employing a coupled atmospheric and snow/sea ice radiative-transfer model (TUV-snow) show that the effects of mineral aerosol deposits is strongly dependent on the snow or sea ice type rather than the differences between the aerosol optical characteristics. The change in albedo between five different mineral aerosol deposits with refractive indices varying by a factor of 2 reaches a maximum of 0.0788, whereas the difference between cold polar snow and melting sea ice is 0.8893 for the same mineral loading. Surprisingly, the thickness of a surface layer of snow or sea ice loaded with the same mass-ratio of mineral dust has little effect on albedo. On the contrary, multiple layers of mineral aerosols deposited during episodic events evenly distributed play a similar role in the surface albedo of snow as a loading distributed throughout, even when the layers are further apart. The impact of mineral aerosol deposits is much larger on melting sea ice than on other types of snow and sea ice. Therefore, the higher input of shortwave radiation during the summer melt cycle associated with melting sea ice accelerates the melt process.

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11

Xie, Zhi Yong, Rui Xuan Tan, Jian Qin Li y Qi Zhong Huang. "Isotropic Pyrolytic Carbon Fabricated by Developing Self-Heating Plates Chemical Vapor Deposition". Advanced Materials Research 284-286 (julio de 2011): 589–96. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.589.

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Isotropic pyrocarbon was deposited on self-heating plate at 1100°C and atmospheric pressure via a novel deposition reactor. Two graphite papers were mounted horizontally in chemical vapor deposition furnace, which were used as self- heating plates with alternating current flowing through them. And the upper surface of the lower self-heating plate also was used as substrate of pyrocarbon deposition. The microstructure of the deposit was investigated by polarized light microscopy, scanning electron microscope, transmission electron microscopy and laser Raman spectra, respectively. The results showed that there were some irregular clusters of globular structure and onion-like structure in the deposits. The thickness and density of deposit were13-15 mm and 1.88 g/cm3in 30h. A novel deposition model of electromagnetic effect on intermediate product has been developed in order to establish a better description of the deposition process.

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12

Lamare, M. L., J. Lee-Taylor y M. D. King. "The impact of atmospheric mineral aerosol deposition on the albedo of snow & sea ice: are snow and sea ice optical properties more important than mineral aerosol optical properties?" Atmospheric Chemistry and Physics 16, n.º 2 (25 de enero de 2016): 843–60. http://dx.doi.org/10.5194/acp-16-843-2016.

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Abstract. Knowledge of the albedo of polar regions is crucial for understanding a range of climatic processes that have an impact on a global scale. Light-absorbing impurities in atmospheric aerosols deposited on snow and sea ice by aeolian transport absorb solar radiation, reducing albedo. Here, the effects of five mineral aerosol deposits reducing the albedo of polar snow and sea ice are considered. Calculations employing a coupled atmospheric and snow/sea ice radiative-transfer model (TUV-snow) show that the effects of mineral aerosol deposits are strongly dependent on the snow or sea ice type rather than the differences between the aerosol optical characteristics. The change in albedo between five different mineral aerosol deposits with refractive indices varying by a factor of 2 reaches a maximum of 0.0788, whereas the difference between cold polar snow and melting sea ice is 0.8893 for the same mineral loading. Surprisingly, the thickness of a surface layer of snow or sea ice loaded with the same mass ratio of mineral dust has little effect on albedo. On the contrary, the surface albedo of two snowpacks of equal depth, containing the same mineral aerosol mass ratio, is similar, whether the loading is uniformly distributed or concentrated in multiple layers, regardless of their position or spacing. The impact of mineral aerosol deposits is much larger on melting sea ice than on other types of snow and sea ice. Therefore, the higher input of shortwave radiation during the summer melt cycle associated with melting sea ice accelerates the melt process.

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13

Fermo, Paola, Sara Goidanich, Valeria Comite, Lucia Toniolo y Davide Gulotta. "Study and Characterization of Environmental Deposition on Marble and Surrogate Substrates at a Monumental Heritage Site". Geosciences 8, n.º 9 (14 de septiembre de 2018): 349. http://dx.doi.org/10.3390/geosciences8090349.

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In this study, the results of the field exposure activity conducted between 2014 and 2017 on the façade of the Milano cathedral (Italy) are reported. The main research aim was to characterize environmental deposition in real exposure conditions and for this purpose, both stone substrates (Candoglia marble) and surrogate substrates (quartz fibre filters) were exposed on the cathedral façade in two sites at different heights. A complete chemical characterization has been performed on quartz filters and marble substrates, i.e., quantification of the deposited aerosol particulate matter (PM) and of the main ions. On quartz filters, the carbonaceous component of deposits was also investigated, as well as the color change induced by soiling, by means of colorimetric measurements. The combined approach exploiting marble and surrogate substrates seems to be a suitable monitoring strategy, although some aspects should be taken into account. In particular, differences in the deposits composition have been highlighted mainly depending on the type of substrate. The environmental data related to atmospheric pollution in Milan for the same period have also been considered but no direct correlations were found between some atmospheric precursors and their related ions in solid deposits.

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14

Cao, J. J., Y. K. Li, T. Jiang y G. Hu. "Sulfur-containing particles emitted by concealed sulfide ore deposits: an unknown source of sulfur-containing particles in the atmosphere". Atmospheric Chemistry and Physics 15, n.º 12 (26 de junio de 2015): 6959–69. http://dx.doi.org/10.5194/acp-15-6959-2015.

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Abstract. Sources of sulfur dioxide, sulfates, and organic sulfur compounds, such as fossil fuels, volcanic eruptions, and animal feeding operations, have attracted considerable attention. In this study, we collected particles carried by geogas flows ascending through soil, geogas flows above the soil that had passed through the soil, and geogas flows ascending through deep faults of concealed sulfide ore deposits, and analysed them using transmission electron microscopy. Numerous crystalline and amorphous sulfur-containing particles or particle aggregations were found in the ascending geogas flows. In addition to S, the particles contained O, Ca, K, Mg, Fe, Na, Pb, Hg, Cu, Zn, As, Ti, Sr, Ba, Si, etc. Such particles are usually a few to several hundred nanometres in diameter with either regular or irregular morphology. The sulfur-containing particles originated from deep-seated weathering or faulting products of concealed sulfide ore deposits. The particles suspended in the ascending geogas flow migrated through faults from deep-seated sources to the atmosphere. This is a previously unknown source of the atmospheric particles. This paper reports, for the first time, the emission of sulfur-containing particles into the atmosphere from concealed sulfide ore deposits. The climatic and ecological influences of these sulfur-containing particles and particle aggregations should be assessed.

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Cranston, Ray E. "Marine sediments as a source of atmospheric methane". Bulletin of the Geological Society of Denmark 41 (30 de marzo de 1994): 101–9. http://dx.doi.org/10.37570/bgsd-1995-41-11.

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Methane sources and sinks have been evaluated at 10 sites off the east coasts of Canada and Russia. More than 99% of the diffusive methane flux from marine sediments appears to be consumed by microbial oxidation when dissolved sulfate is present. At 3 sites, methane bubble vents were found. Two of the vents, located in the Okhotsk Sea, appear to result from gas being released along faults. The third plume site was located in a shallow harbour where a large amount of organic carbon is deposited in shallow water. The global diffusive and advective (bubbles) release of methane to the atmosphere from marine sediments is estimated to fall into the range of 1 - 10 TgC a-1 (1 Tg = 1012 g). Researchers have speculated that marine gas hydrate deposits hold vast quantitites of methane that may melt and be released as a result of global warming. A warmer atmosphere could directly heat the ocean and/or change ocean current systems, which could bring warmer water to some areas. Hydrate samples were recovered from two sites in the Okhotsk Sea. These deposits, in 700 to 800 m of water, would require water temperatures to increase by 8°C in order to melt the hydrate. Quantitative estimates of hydrate reservoirs near the minimum pressure stability zone are needed to remove the uncertainty whether this will be a significant positive feedback loop for global warming.

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Gleeson, S. A., C. R. M. Butt y M. Elias. "Nickel Laterites: A Review". SEG Discovery, n.º 54 (1 de julio de 2003): 1–18. http://dx.doi.org/10.5382/segnews.2003-54.fea.

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ABSTRACT Nickel laterite deposits are formed by the prolonged and pervasive weathering of Ni silicate-bearing ultramafıc rocks, generally in tropical to subtropical climates. The deposits can be further classifıed as hydrous silicate deposits (e.g., SLN Operations, New Caledonia), clay silicate deposits (e.g., Murrin Murrin, Australia), and oxide deposits (e.g., Moa Bay, Cuba; Cawse, Australia) on the basis of the ore mineralogy. The physical and chemical nature of a nickel laterite deposit is a function of many factors, including the composition of the parent rock, the tectonic setting, climate, topography (specifıcally, laterite morphology), and drainage. Nickel laterite ore is extracted using both selective and bulk mining methods in open cast mining operations. The mined ore has traditionally been processed either by hydrometallurgical leaching technology (pressure acid leach or Caron processes) to produce oxides of nickel and cobalt or mixed Ni-Co sulfıdes for market, or by pyrometallurgical smelting to produce ferronickel granules or nickel matte. However, recent advances in high-pressure acid leaching and continued testing of atmospheric leach technology should lead to a reduction in overall operating costs and increased exploitation of Ni laterite resources in the future.

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17

Schweighofer, B. "The geology of ore deposits". Meteorology and Atmospheric Physics 35, n.º 4 (1986): 253. http://dx.doi.org/10.1007/bf01041818.

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18

Tesfamichael, Tekie. "Late Oligocene atmospheric carbon dioxide concentrations reconstructed from fossil leaves using stomatal index". Journal of Palaeosciences 72, n.º 2 (22 de diciembre de 2023): 119–26. http://dx.doi.org/10.54991/jop.2023.1860.

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Ancient atmospheric CO2 can be reconstructed using various climate proxies; stomata from fossil leaves are one of the climate proxies that provide critical information about past climatic conditions of the Earth. Exceptionally well–preserved fossil leaves found in overbank deposits in Chilga of Northwest Ethiopia were used to estimate late Oligocene atmospheric CO2 values using stomatal index. The age of the fossils, 206Pb/238U: 27.23 ± 0.03 Ma, was determined from zircons in an ash deposit comprising the matrix deposited contemporaneously with the fossil leaves. Stomatal indices were calculated from both the fossil leaves and nearest living relatives of the fossils. Corresponding atmospheric CO2 values for the nearest living relatives of the fossils were assigned from historical records from the Mauna Loa Observatory. This produces a calibrating curve that shows variation of atmospheric CO2 over time, and late Oligocene atmospheric CO2 values were quantified from the calibrating curve. The quantified late Oligocene atmospheric CO2 values are about 343 ± 11 ppm which show a 12 % decrease when they are quantified using a leaf gas exchange method. This is consistent with the idea that stomatal–index method underestimates CO2 values compared to the leaf gas exchange method. The late Oligocene was colder than both its preceding Eocene and its following Miocene epochs, and the results are incongruent with the cold Oligocene period. These results for this particular geologic time provide opportunity to examine how plants responded to climate changes in the past and have important implications for the study of current and future climate changes.

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Kikawada, Yoshikazu, Kohei Oda, Masao Nomura, Teruyuki Honda, Takao Oi, Katsumi Hirose y Yasuhito Igarashi. "Origin of enriched uranium contained in Japanese atmospheric deposits". Natural Science 04, n.º 11 (2012): 936–42. http://dx.doi.org/10.4236/ns.2012.431122.

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KIKAWADA, Yoshikazu, Kohei ODA, Rieko YAMAUCHI, Masao NOMURA, Teruyuki HONDA, Takao OI, Katsumi HIROSE y Yasuhito IGARASHI. "Anomalous Uranium Isotope Ratio in Atmospheric Deposits in Japan". Journal of Nuclear Science and Technology 46, n.º 12 (diciembre de 2009): 1094–98. http://dx.doi.org/10.1080/18811248.2009.9711621.

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Rubio Montero, M. P. y A. Martı́n Sánchez. "Activity of 239+240Pu and 238Pu in atmospheric deposits". Applied Radiation and Isotopes 55, n.º 1 (julio de 2001): 97–102. http://dx.doi.org/10.1016/s0969-8043(00)00365-1.

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22

Rong, X., D. Waite, G. H. Huang, L. Tong y B. Kybett. "Materials selection for a dry atmospheric mercury deposits sampler". Chemosphere 45, n.º 6-7 (noviembre de 2001): 1045–51. http://dx.doi.org/10.1016/s0045-6535(01)00057-1.

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MÖLLER, REBECCA, MARCO MÖLLER, PETER A. KUKLA y CHRISTOPH SCHNEIDER. "Impact of supraglacial deposits of tephra from Grímsvötn volcano, Iceland, on glacier ablation". Journal of Glaciology 62, n.º 235 (18 de julio de 2016): 933–43. http://dx.doi.org/10.1017/jog.2016.82.

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ABSTRACTSupraglacial deposits are known for their influence on glacier ablation. The magnitude of this influence depends on the thickness and the type of the deposited material. The effects of thin layers of atmospheric black carbon and of thick moraine debris have been intensively studied. Studies related to regional-scale deposits of volcanic tephra with thicknesses varying between millimetres and metres and thus over several orders of magnitude are scarce. We present results of a field experiment in which we investigated the influence of supraglacial deposits of tephra from Grímsvötn volcano on bare-ice ablation at Svínafelsjökull, Iceland. We observed that the effective thickness at which ablation is maximized ranges from 1.0 to 2.0 mm. At ~10 mm a critical thickness is reached where sub-tephra ablation equals bare-ice ablation. We calibrated two empirical ablation models and a semi-physics-based ablation model that all account for varying tephra-layer thicknesses. A comparison of the three models indicates that for tephra deposits in the lower-millimetre scale the temperature/radiation-index model performs best, but that a semi-physics-based approach could be expected to yield superior results for tephra deposits of the order of decimetres.

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Kawamura, Kimitaka, Bhagawati Kunwar, Dhananjay Kumar Deshmukh, Petr Vodička y Md Mozammel Haque. "Deposition of Potassium on Chimney Wall from Wood Stove Smoke: Implication for the Influence of Domestic Biomass Burning on Atmospheric Aerosols". Atmosphere 14, n.º 3 (28 de febrero de 2023): 484. http://dx.doi.org/10.3390/atmos14030484.

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Based on the field studies of biomass burning plumes in Alaska, we hypothesized that potassium (K) may be significantly scavenged, during wood stove burning, as deposits on the inner wall of the chimney where the temperature decreases with the height. To test this hypothesis, we analyzed chimney deposit samples collected from the inner wall of a chimney (6 m long) for the measurement of major ions and anhydrosugars including levoglucosan (Lev). Concentrations of K were found to be highest in the lower part of the chimney with a decreasing trend with height, whereas Lev showed an opposite trend with the lowest concentrations near the bottom of the chimney and an increase with height. We detected an anti-correlation between the two components in the chimney deposits, confirming that K is largely scavenged as a deposit within the chimney while Lev is significantly emitted to the ambient air. We propose that, using K/Lev mass ratios, the relative contributions of open fires and domestic wood burning to ambient aerosols can be evaluated.

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Kovalev, A. A., V. A. Karpov, V. А. Makarov y N. L. Padalko. "Using isotope-geochemical criteria for Olympiadinskoye gold deposit gas system genesis diagnosis". Earth sciences and subsoil use 47, n.º 1 (28 de abril de 2024): 17–34. http://dx.doi.org/10.21285/2686-9993-2024-47-1-17-34.

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The authors studied modern gas manifestations spatially associated with the ore deposits in the Kaitbinskaya lithological-facies zone of the Yenisei Ridge. The purpose of the research is to obtain scientifically based data on the genesis of gaseous and vaporous fluids in various sampling environments of the Vostochny open-pit mine of the Olympiadinskoye gold deposit: rocks, natural waters, free-flowing gases from blastholes and air of the surface atmosphere. It has been conducted a complex of field and analytical works including degassing, gas chromatography, pyrolysis of the organic substance of lithified and metamorphosed deposits, analysis of carbon isotopic composition in carbon dioxide and methane in fluidal systems. In order to study normal gas-geochemical field (natural background) of the work area an atmospheric geochemical survey was carried out at the reference site – an “environmentally friendly” site with the minimal influence of technogenic factors. It has been determined that the surface atmosphere of the site had been formed due to the landscape and geomorphological conditions of the Kaitbinskaya lithological-facies zone as well as fluidal systems of deep horizons. The latter, due to the presence of an extensive network of disruptive disturbances and diffusion-filtration processes of mass transfer reached the zone of exploratory geochemical sounding. The conducted pyrolytic studies of rocks have proved that within the open section of the Vostochny open-pit mine the organic substance of the Kordinskaya series of the lower Riphean deposits has implemented its oil and gas generation potential and cannot serve the formation source of abnormal gas fields of the Olympiadinskoye gold deposit. The studied gas systems are polygenic in nature and, being allochthonous to the host sediments, are formed without the participation of gases from the upper generating (bio) zone. According to isotope-geochemical criteria, these are mainly endogenous and naphthidogenic fluids identical to the gas condensate accumulations of the Yurubcheno-Tokhomskaya oil and gas accumulation zone.

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26

Lin, Yongchong, Guijin Mu y Lishuai Xu. "Grain Size and Sedimentary Sorting Characteristics of Atmospheric Dust in the Cele Oasis, Southern Margin of Taklimakan Desert". Sustainability 14, n.º 13 (1 de julio de 2022): 8093. http://dx.doi.org/10.3390/su14138093.

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Grain size is a proxy indicator of airflow intensity and also provides a scientific basis for the prevention of dust hazards. However, the variations in grain size characteristics that occur during transport and deposition processes are seldom discussed. Here, atmospheric dust samples were collected before and after deposition in a sand–dust storm for grain size analysis. The results showed that the grain size distributions of the atmospheric dust were unimodal during transportation but always became bimodal after deposition. This indicates that the bimodal grain size distribution of the aeolian deposits was caused by sedimentary sorting. The coarse-grained component, which was between 20 and 200 μm, was mainly deposited during the sand–dust storm. Grain size may indicate the strength of the airflow field. The fine-grained component, which ranged in size from 0.4 to 20 μm, was mainly deposited after the sand–dust storm. This component can remain suspended in the atmosphere for a long period of time. Oasis shelterbelts can be used to reduce the fine-grained component of the dust aerosol through the interception of particles by foliage. The grain size variation found in this study from before to after sand–dust storm deposition deepens our understanding of the sediment sorting process.

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27

Prezerakos, N. G., A. G. Paliatsos y K. V. Koukouletsos. "Diagnosis of the Relationship between Dust Storms over the Sahara Desert and Dust Deposit or Coloured Rain in the South Balkans". Advances in Meteorology 2010 (2010): 1–14. http://dx.doi.org/10.1155/2010/760546.

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The main objects of study in this paper are the synoptic scale atmospheric circulation systems associated with the rather frequent phenomenon of coloured rain and the very rare phenomenon of dust or sand deposits from a Saharan sandstorm triggered by a developing strong depression. Analysis of two such cases revealed that two days before the occurrence of the coloured rain or the dust deposits over Greece a sand storm appeared over the north-western Sahara desert. The flow in the entire troposphere is southerly/south-westerly with an upward vertical motion regime. If the atmospheric conditions over Greece favour rain then this rain contains a part of the dust cloud while the rest is drawn away downstream adopting a light yellow colour. In cases where the atmospheric circulation on the route of the dust cloud trajectories is not intensively anticyclonic dust deposits can occur on the surface long far from the region of the dust origin. Such was the case on 4th April, 1988, when significant synoptic-scale subsidence occurred over Italy and towards Greece. The upper air data, in the form of synoptic maps, illustrate in detail the synoptic-scale atmospheric circulations associated with the emission-transport-deposition and confirm the transportation of dust particles.

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28

Lahermo, Pertti W. "Atmospheric, Geological, Marine and Anthropogenic Effects on Groundwater Quality in Finland". Water Science and Technology 20, n.º 3 (1 de marzo de 1988): 33–39. http://dx.doi.org/10.2166/wst.1988.0078.

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The atmospheric, geological, marine and anthropogenic factors affecting the chemical quality of groundwater are evaluated. Sulphates and nitrates derive mainly from the atmosphere as wet or dry deposition in weakly mineralized shallow groundwater in natural uncontaminated surficial aquifers. The texture, structure and lithologic composition of aquifer material have an impact on water chemistry although marine influence and anthropogenic pollution generally outweigh the geological influence. Relict seawater trapped in deeper parts of confined aquifers and in bedrock covered by clay deposits has a marked effect on the quality of groundwater drawn from wells drilled into bedrock in the broad coastal belt. Brackish or saline groundwater is encountered all over the country in holes drilled in crystalline bedrock to a depth of more than 500 to 1000 metres. The lithologic environment affects the quality of deep bedrock groundwater which tends to change from Na-Cl type towards Ca-Na-Cl type with increasing salinity and depth of occurrence. Anthropogenic pollution is reflected in elevated amounts of all major dissolved components, although the most sensitive indicators of contamination are nitrates, chlorides and potassium. Nation-wide hydrogeochemical mapping of rural water sources revealed that shallow wells dug into glacial till deposits had the highest median NO3 contents, and that spring water discharging from glaciofluvial sand deposits had the lowest. The quality of groundwater distributed by public waterworks is generally good.

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29

Walz, Josefine, Christian Knoblauch, Ronja Tigges, Thomas Opel, Lutz Schirrmeister y Eva-Maria Pfeiffer. "Greenhouse gas production in degrading ice-rich permafrost deposits in northeastern Siberia". Biogeosciences 15, n.º 17 (13 de septiembre de 2018): 5423–36. http://dx.doi.org/10.5194/bg-15-5423-2018.

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Abstract. Permafrost deposits have been a sink for atmospheric carbon for millennia. Thaw-erosional processes, however, can lead to rapid degradation of ice-rich permafrost and the release of substantial amounts of organic carbon (OC). The amount of the OC stored in these deposits and their potential to be microbially decomposed to the greenhouse gases carbon dioxide (CO2) and methane (CH4) depends on climatic and environmental conditions during deposition and the decomposition history before incorporation into the permafrost. Here, we examine potential greenhouse gas production as a result of degrading ice-rich permafrost deposits from three locations in the northeastern Siberian Laptev Sea region. The deposits span a period of about 55 kyr from the last glacial period and Holocene interglacial. Samples from all three locations were incubated under aerobic and anaerobic conditions for 134 days at 4 ∘C. Greenhouse gas production was generally higher in deposits from glacial periods, where 0.2 %–6.1 % of the initially available OC was decomposed to CO2. In contrast, only 0.1 %–4.0 % of initial OC was decomposed in permafrost deposits from the Holocene and the late glacial transition. Within the deposits from the Kargin interstadial period (Marine Isotope Stage 3), local depositional environments, especially soil moisture, also affected the preservation of OC. Sediments deposited under wet conditions contained more labile OC and thus produced more greenhouse gases than sediments deposited under drier conditions. To assess the greenhouse gas production potentials over longer periods, deposits from two locations were incubated for a total of 785 days. However, more than 50 % of total CO2 production over 785 days occurred within the first 134 days under aerobic conditions, while 80 % were produced over the same period under anaerobic conditions, which emphasizes the nonlinearity of the OC decomposition processes. Methanogenesis was generally observed in active layer samples but only sporadically in permafrost samples and was several orders of magnitude smaller than CO2 production.

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30

King, Gary M. "Contributions of Atmospheric CO and Hydrogen Uptake to Microbial Dynamics on Recent Hawaiian Volcanic Deposits". Applied and Environmental Microbiology 69, n.º 7 (julio de 2003): 4067–75. http://dx.doi.org/10.1128/aem.69.7.4067-4075.2003.

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ABSTRACT A series of sites were established on Hawaiian volcanic deposits ranging from about 18 to 300 years old. Three sites occurred in areas that supported tropical rain forests; the remaining sites were in areas that supported little or no plant growth. Sites >26 years old consumed atmospheric CO and hydrogen at rates ranging from about 0.2 to 5 mg of CO m−2 day−1 and 0.1 to 4 mg of H2 m−2 day−1, respectively. Respiration, measured as CO2 production, for a subset of the sites ranged from about 40 to >1,400 mg of CO2 m−2 day−1. CO and H2 accounted for about 13 to 25% of reducing equivalent flow for all but a forested site, where neither substrate appeared significant. Based on responses to chloroform fumigation, hydrogen utilization appeared largely due to microbial uptake. In contrast to results for CO and hydrogen, methane uptake occurred consistently only at the forest site. Increasing deposit age was generally accompanied by increasing concentrations of organic matter and microbial biomass, measured as phospholipid phosphate. Exoenzymatic activities (acid and alkaline phosphatases and α- and β-glucosidases) were positively correlated with deposit age in spite of considerable variability within sites. The diversity of substrates utilized in Biolog Ecoplate assays also increased with deposit age, possibly reflecting changes in microbial community complexity.

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31

Baránková, Hana y Ladislav Bárdos. "Atmospheric pressure plasma conversion of CO 2 to solid deposits". Results in Physics 5 (2015): 257–58. http://dx.doi.org/10.1016/j.rinp.2015.08.011.

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32

Li, Bo, Tao Yu, Wenbing Ji, Xu Liu, Kun Lin, Cheng Li, Xudong Ma y Zhongfang Yang. "Geochemical Response of Surface Environment to Mining of Sn-Pb-Zn Sulfide Deposits: A Case Study of Dachang Tin Polymetallic Deposit in Guangxi". Water 15, n.º 8 (14 de abril de 2023): 1550. http://dx.doi.org/10.3390/w15081550.

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The rational development of mineral resources provides necessary materials for economic development, but environmental pollution caused by mining activities is an inevitable consequence. Here, we present a case study of Chehe Town in Guangxi, an area with integrated metals mining and smelting. The geochemical distribution, migration, and transformation behaviors of Cd and other heavy metals were studied in detail by systematically collecting surface media such as atmospheric dust, surface water and stream sediments, ores, tailings, mine drainage, soil, and crops in and around the mining area. We used these data to explore the geochemical response of the surface environment to mining and smelting of metal sulfide deposits. The annual flux of Cd and other heavy metals near the mining and smelting sites was high. Due to the topography, heavy metals in the atmosphere are mainly transported via vertical deposition, influencing areas downwind for 25 km. The mine drainage exceeded As and Zn standards but had little impact on the surface water. The surface water quality was good, without acidification. Risks due to ore were much higher than that for tailings. Heavy metals buffered by surrounding carbonate rocks and secondary minerals mainly migrated as solid particles, resulting in the contamination of stream sediment by heavy metals. In mountainous areas, rivers are mainly affected by topography, flowing fast and dominated by downcutting, which caused heavy metal pollution in the sediment have a limited effect on the soil near the river. Heavy metal concentrations in the cultivated soil were greatly influenced by external input such as substantial atmospheric dust. However, only Cd accumulated in the crops, with very high concentrations in rice, but safe and edible levels in corn. Thus, in the mining area, the most sensitive to heavy metals was the atmospheric environment. High concentrations of heavy metals beyond the ore district are mainly concentrated in the sediment, with distant impacts. Therefore, it is necessary to monitor and control risks associated with sediment transport, conduct treatment, and adjust crop planting. The soil, river, and agriculture respond differently to mining activities, but the risk is low and can be managed as needed.

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33

Cao, J., Y. Li, T. Jiang y G. Hu. "Sulfur-containing particles emitted by concealed sulfide ore deposits: an unknown source of sulfur-containing particles in the atmosphere". Atmospheric Chemistry and Physics Discussions 14, n.º 21 (17 de noviembre de 2014): 28299–331. http://dx.doi.org/10.5194/acpd-14-28299-2014.

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Abstract. Sources of sulfur dioxide, sulfates, and organic sulfur compounds, such as fossil fuels, volcanic eruptions, and animal feeding operations, have attracted considerable attention. In this study, we collected particles carried by geogas flows ascending through soil, geogas flows above the soil that had passed through the soil, and geogas flows ascending through deep faults of concealed sulfide ore deposits and analyzed them using transmission electron microscopy. Numerous crystalline and amorphous sulfur-containing particles or particle aggregations were found in the ascending geogas flows. In addition to S, the particles contained O, Ca, K, Mg, Fe, Na, Pb, Hg, Cu, Zn, As, Ti, Sr, Ba, Si, etc. Such particles are usually a few to several hundred nanometers in diameter with either regular or irregular morphology. The sulfur-containing particles originated from deep-seated weathering or faulting products of concealed sulfide ore deposits. The particles suspended in the ascending geogas flow migrated through faults from deep-seated sources to the atmosphere. This is a previously unknown source of the atmospheric particles. This paper reports, for the first time, the emission of sulfur-containing particles into the atmosphere from concealed sulfide ore deposits. The climatic and ecological influences of these sulfur-containing particles and particle aggregations should to be assessed.

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34

Mahmood, S., C. Gallagher y D. L. Engelberg. "Atmospheric Corrosion of Aluminum Alloy 6063 Beneath Ferric Chloride Corrosion Product Droplets". Corrosion 76, n.º 10 (29 de julio de 2020): 985–94. http://dx.doi.org/10.5006/3558.

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The atmospheric corrosion behavior of aluminum alloy 6063-T5 with exposure to FeCl3-containing droplet deposits has been investigated using x-ray computed tomography analysis. A voluminous corrosion product cap is formed, with iron oxyhydroxide/oxide deposits forming a coherent layer at the aluminum interface. Exposure to a single droplet is compared with exposure to multiple droplets, and the effect of corrosion product development and FeCl3 concentration on the corrosion rate has been determined. Multiple wet periods with small droplet volumes resulted in higher corrosion rates than comparable single droplet exposures.

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35

Lekobou, William P., Karl R. Englund, Marie-Pierre Laborie y Patrick D. Pedrow. "Influence of atmospheric pressure plasma treatments on the surface properties of ligno-cellulosic substrates". Holzforschung 70, n.º 1 (1 de enero de 2016): 55–61. http://dx.doi.org/10.1515/hf-2014-0211.

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AbstractThe paper aims at the investigation of atmospheric pressure weakly ionized plasmas with argon and acetylene to deposit plasma-polymerized coatings on wood veneers (birch, maple), cellulose paper, and pine wood flour to modify their surface properties, in particular their topography and wettability. The treatment was performed in a reactor containing an array of high-voltage needles and a grounded metallic mesh as electrodes. The deposition occurred in the discharge downstream of the plasma region. The plasma-polymerized acetylene deposits form spherical nodules on the surface of the substrates and change their wettability from hydrophilic to hydrophobic. The water contact angles of the veneer were determined with a goniometer. The capillary rise was combined with the Washburn equation to assess the change in hydrophilicity of the plasma-treated wood flour.

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36

Vasilevsky, Michail, Aleksandr Razva, Dmitri Zaharov y Danil Shabirov. "The modeling of the dust deposits on the surfaces of cyclone scrubber". MATEC Web of Conferences 194 (2018): 01047. http://dx.doi.org/10.1051/matecconf/201819401047.

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The phenomena at interaction of agglomerate of disperse material with the surface of the inertial device are considered. It is revealed that tension in the interactions between the agglomerate surface can reach values comparable to atmospheric pressure, which is the reason for the formation of solid deposits, what is the reason of formation of strong deposits which, in turn, are defined by the autohesion communications of particles forming agglomerate.

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37

Rincón-Tomás, Blanca, Bahar Khonsari, Dominik Mühlen, Christian Wickbold, Nadine Schäfer, Dorothea Hause-Reitner, Michael Hoppert y Joachim Reitner. "Manganese carbonates as possible biogenic relics in Archean settings". International Journal of Astrobiology 15, n.º 3 (julio de 2016): 219–29. http://dx.doi.org/10.1017/s1473550416000264.

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AbstractCarbonate minerals such as dolomite, kutnahorite or rhodochrosite are frequently, but not exclusively generated by microbial processes. In recent anoxic sediments, Mn(II)carbonate minerals (e.g. rhodochrosite, kutnahorite) derive mainly from the reduction of Mn(IV) compounds by anaerobic respiration. The formation of huge manganese-rich (carbonate) deposits requires effective manganese redox cycling in an oxygenated atmosphere. However, putative anaerobic pathways such as microbial nitrate-dependent manganese oxidation, anoxygenic photosynthesis and oxidation in ultraviolet light may facilitate manganese cycling even in an early Archean environment, without the availability of oxygen. In addition, manganese carbonates precipitate by microbially induced processes without change of the oxidation state, e.g. by pH shift. Hence, there are several ways how these minerals could have been formed biogenically and deposited in Precambrian sediments. We will summarize microbially induced manganese carbonate deposition in the presence and absence of atmospheric oxygen and we will make some considerations about the biogenic deposition of manganese carbonates in early Archean settings.

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38

Yakovlev, Evgeny, Alexander Orlov, Alina Kudryavtseva y Sergey Zykov. "Estimation of Physicochemical Parameters and Vertical Migration of Atmospheric Radionuclides in a Raised Peat Bog in the Arctic Zone of Russia". Applied Sciences 12, n.º 21 (26 de octubre de 2022): 10870. http://dx.doi.org/10.3390/app122110870.

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The article presents the results of a study of activity levels and features of the vertical distribution of 210Pb, 137Cs, 234U, 238U and their relationship with the physicochemical parameters of peat deposits. Analysis of the data showed that the vertical distribution of 137Cs and 210Pb was related to the content of water-soluble salts, the water saturation of the deposit, and the values of Eh (oxidation–reduction potential) and rH (relative humidity), which indicates a complex geochemical barrier at a depth of 20 cm in the peat core. The 210Pb dating of the peat core, carried out according to the CF model using the Monte Carlo method (to improve the dating accuracy), showed that the above horizon corresponded to 1963, which is consistent with the data of the 137Cs reference horizon and in terms of several physicochemical parameters (in particular, ash content) also corresponds to the age of 1963, which confirms the correctness and adequacy of the chosen peat core dating model. The peak of anthropogenic radionuclides in peat deposits correlates with a particular major event in the history of radioactive fallout, the Partial Nuclear Test Ban Treaty of 1963, providing a benchmark for geochronological research. The obtained results of the linear accumulation rate, the mass accumulation rate of the peat deposit, and the value of the atmospheric flux of 210Pb are congruent with the data on the peatlands of Northern Europe and the data obtained by earlier analysts of the Subarctic region of European Russia.

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39

Sergacheva, Evgeniya y Tamara Filippova. "DISTRIBUTION OF ATMOSPHERIC AIR POLLUTANTS HAZARD CLASSES AT GAS CONDENSATE DEPOSITS". Modern Technologies and Scientific and Technological Progress 1, n.º 1 (17 de mayo de 2021): 272–73. http://dx.doi.org/10.36629/2686-9896-2021-1-1-272-273.

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40

Rousseau, Denis-Didier, Catherine Chauvel, Adriana Sima, Christine Hatté, France Lagroix, Pierre Antoine, Yves Balkanski et al. "European glacial dust deposits: Geochemical constraints on atmospheric dust cycle modeling". Geophysical Research Letters 41, n.º 21 (12 de noviembre de 2014): 7666–74. http://dx.doi.org/10.1002/2014gl061382.

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41

Bronić, Ines Krajcar, Nada Horvatinčić, Dušan Srdoč y Bogomil Obelić. "Experimental Determination of the 14C Initial Activity of Calcareous Deposits". Radiocarbon 34, n.º 3 (1992): 593–601. http://dx.doi.org/10.1017/s0033822200063876.

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We have reconstructed the initial activity of calcareous sediments by 1) measuring the 14C activity of recent pre-bomb-test calcareous deposits, 2) calculating the ratio of the 14C activity of the calcareous sediment to that of the adjacent coeval wood, and 3) extrapolating 14C activity of the deep lacustrine sediment layers to the surface, assuming a constant sedimentation rate. We show here that the uppermost sediment is affected by the global increase of atmospheric 14C activity due to thermonuclear bomb tests in the early 1960s. 14C activity of submerged aquatic plants showed values similar to 14C activity of DIC. Thus, organic residue of the sediment cannot be used for reliable 14C dating because of the unknown fraction of aquatic plant detritus. The initial activity, A0, obtained in a case study of the geochronology of carbonates in the Plitvice Lakes area, ranged from 70.5 to 72.2 pMC for Lake Prošće sediment, and from 75.9 to 76.7 pMC for Lake Kozjak sediment. These values also agree with calculated values based on the downstream increase of 14C activity of DIC in freshwater open to the atmosphere.

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42

DePoy, Amber N., Gary M. King y Hiroyuki Ohta. "Anaerobic Carbon Monoxide Uptake by Microbial Communities in Volcanic Deposits at Different Stages of Successional Development on O-yama Volcano, Miyake-jima, Japan". Microorganisms 9, n.º 1 (22 de diciembre de 2020): 12. http://dx.doi.org/10.3390/microorganisms9010012.

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Research on Kilauea and O-yama Volcanoes has shown that microbial communities and their activities undergo major shifts in response to plant colonization and that molybdenum-dependent CO oxidizers (Mo-COX) and their activities vary with vegetation and deposit age. Results reported here reveal that anaerobic CO oxidation attributed to nickel-dependent CO oxidizers (Ni-COX) also occurs in volcanic deposits that encompass different developmental stages. Ni-COX at three distinct sites responded rapidly to anoxia and oxidized CO from initial concentrations of about 10 ppm to sub-atmospheric levels. CO was also actively consumed at initial 25% concentrations and 25 °C, and during incubations at 60 °C; however, uptake under the latter conditions was largely confined to an 800-year-old forested site. Analyses of microbial communities based on 16S rRNA gene sequences in treatments with and without 25% CO incubated at 25 °C or 60 °C revealed distinct responses to temperature and CO among the sites and evidence for enrichment of known and potentially novel Ni-COX. The results collectively show that CO uptake by volcanic deposits occurs under a wide range of conditions; that CO oxidizers in volcanic deposits may be more diverse than previously imagined; and that Ni-dependent CO oxidizers might play previously unsuspected roles in microbial succession.

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43

Gini, Irene, Alessandra Balzarini, Guido Pirovano, Anna Maria Toppetti, Lucio Fialdini, Paolo Omodeo, Giovanni Pirovano et al. "On the Chemical Composition and Hygroscopicity of Aerosols Deposited on the Insulators of Italian Power Lines". Applied Sciences 13, n.º 23 (29 de noviembre de 2023): 12788. http://dx.doi.org/10.3390/app132312788.

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The reliability of the national power grid is a key issue in modern society. Atmospheric aerosols are the main cause of the reduction in the performance of insulators and the increase in the possibility of flashovers, resulting in power line failures. Under high ambient humidity, the water-soluble compounds of atmospheric aerosols collected on the insulators’ surface can dissociate in ions and form a conductive layer, which may lead to flashover events. With a view to investigating the processes that drive these phenomena, the chemical composition of aerosol deposits on insulators in Italy was determined by ion chromatography analysis and thermos-optical and X-ray techniques. In addition, a synthetic aerosol with the same analyzed chemical composition was generated in a laboratory and deposited on PTFE filters and glass specimens allowing us to determine the deliquescence and crystallization relative humidity and the conductive effect in an aerosol exposure chamber. The results evidenced the presence of a hazardous inorganic ion layer, which generates a sharp phase transition of the aerosol deposit as a function of the ambient relative humidity; this layer poses a dangerous threat to the reliability of the power grid, increasing the probability of flashover events where the conductive layer facilitates the flow of electrical current across the insulator surface, potentially causing power outages or damage to the power lines.

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44

MILYAEV, SERGEI. "Ore deposit prospecting using the chlorine and bromine secondary dispersion halos". Domestic geology, n.º 5 (22 de noviembre de 2023): 26–34. http://dx.doi.org/10.47765/0869-7175-2023-10022.

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The Cland Brions, that form complex compounds with metals, produce secondary dispersion halos in the hypergenesis zone at Au, Ag, Cu, Pb, and Zn ore deposits which ore bodies are controlled by fracturing and fault structures. The appearance of anomalies of the highly mobile water-soluble ions, manifested on the surface and in the wall rocks, is explained by their transfer from the deep sources to the surface by a gas flow. The migration of the ions to the earth's surface and further into the atmosphere is influenced by many factors (atmospheric pressure, temperature, humidity, rock porosity, etc.) that complicate the observation results.

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45

Zhu, B. Q. "Atmospheric significance of aeolian salts in the sandy deserts of northwestern China". Solid Earth 7, n.º 1 (4 de febrero de 2016): 191–203. http://dx.doi.org/10.5194/se-7-191-2016.

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Abstract. Large sandy deserts in the middle latitudes of northwestern China were investigated for soluble salt variations in modern and ancient aeolian sediments, aiming to explore the environmental significance of “aeolian salts”. Results revealed that aeolian salt variations have a clear relationship with the changing meridional and zonal gradients of the desert locations and the aeolian differentiation effect, but are weakly linked to local geological conditions. Atmospheric depositions of water-soluble chemical species are an important process/source contributing to aeolian salt. Sequential variations of soluble salts in sedimentary profiles interbedded with aeolian and non-aeolian deposits and their palaeoenvironmental implications in the hinterland areas of these deserts were further evaluated, based on the constraints of OSL dating and radiocarbon dating data. The results indicate that inorganic salts may be a latent geoproxy in revealing regional palaeoclimatic changes in desert areas for sediments deposited under a single depositional environment, but the interpretation should be more cautious for sediments deposited under diverse depositional conditions. This study presents evidence of the atmospheric origin of aeolian salt in sandy deserts, with limited climatic significance in palaeoenvironmental reconstruction.

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46

Mattsson, Jan O. "Brightness contrasts in drop deposits due to specular reflection". Weather 61, n.º 2 (1 de febrero de 2006): 51–52. http://dx.doi.org/10.1256/wea.16.05.

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47

Weninger, Bernhard. "Stratified 14C Dates and Ceramic Chronologies: Case Studies for the Early Bronze Age at Troy (Turkey) and Ezero (Bulgaria)". Radiocarbon 37, n.º 2 (1995): 443–56. http://dx.doi.org/10.1017/s0033822200030927.

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Prehistoric tell stratigraphies, like deep-sea sediments or peat deposits, store information about past atmospheric 14C variations. By matching the 14C ages on charcoal samples from settlement deposits with the tree-ring calibration curve, estimates for the time span covered by successive stratigraphic phases can be derived. This method is applied to 14C data from the tell mounds at Troy, Turkey and Ezero, Bulgaria. I compare the derived chronologies with the results of pottery shape seriation using correspondence analysis.

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48

Ball, E. R., W. J. M. Seviour y D. M. Mitchell. "The Importance of Isentropic Mixing in the Formation of the Martian Polar Layered Deposits". Planetary Science Journal 4, n.º 11 (1 de noviembre de 2023): 213. http://dx.doi.org/10.3847/psj/ad045d.

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Abstract Layers of ice and dust at the poles of Mars reflect variations in orbital parameters and atmospheric processes throughout the planet's history and may provide a key to understanding Mars's climate record. Previous research has investigated transport changes into the polar regions and found a nonlinear response to obliquity that suggests that Mars may currently be experiencing a maximum in transport across the winter poles. The thickness and composition of layers within the polar layered deposits (PLDs) are likely influenced by changes in horizontal atmospheric mixing at the poles, which is an important component of the transport of aerosols and chemical tracers. No study has yet investigated horizontal mixing alone, which may be influenced by polar vortex morphology. We show that mixing in an idealized Martian global climate model varies significantly with obliquity and dust abundance by using a diagnostic called effective diffusivity, which has been used to study the stratospheric polar vortices on Earth and to understand their role as a mixing barrier but has not been applied to Mars's polar vortices. We find that mixing in the winter southern hemisphere doubles with either an octupling of dust loading or an increase in obliquity from 10° to 50°. We find a weaker response to changing dust loading or obliquity in the northern hemisphere. We demonstrate that horizontal mixing is an important component of transport into Mars’s polar regions, may contribute to the formation of the PLDs, and presents effective diffusivity as a useful method to understand mixing in the Martian atmosphere.

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49

Cizdziel, James V. "Atmospheric Mercury Monitoring, Analysis, and Chemistry: New Insights and Progress toward Minamata Convention Goals". Atmosphere 12, n.º 2 (28 de enero de 2021): 166. http://dx.doi.org/10.3390/atmos12020166.

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50

Hammer, C. U. "The Influence On Atmospheric Composition of Volcanic Eruptions as Derived From Ice-Core Analysis". Annals of Glaciology 7 (1985): 125–29. http://dx.doi.org/10.3189/s0260305500006029.

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Polar ice cores offer datable past snow deposits in the form of annual ice layers, which reflect the past atmospheric composition. Trace substances in the cores are related to the past mid-tropospheric impurity load, this being due to the vast extent of the polar ice sheets (or ice caps), their surface elevations and remoteness from most aerosol sources. Volcanic eruptions add to the rather low background impurity load via their eruptive products. This paper concentrates on the widespread influence on atmospheric impurity loads caused by the acid gas products from volcanic eruptions. In particular the following subjects are discussed: acid volcanic signals in ice cores, latitude of eruptions as derived by ice-core analysis, inter-hemispheric dating of the two polar ice sheets by equatorial eruptions, volcanic deposits in ice cores during the last glacial period and climatic implications.

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