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31.
Water-soluble organics in atmospheric particles: A critical review of the literature and application of thermodynamics to identify candidate compounds 总被引:15,自引:0,他引:15
Although organic compounds typically constitute a substantial fraction of the fine particulate matter (PM) in the atmosphere, their molecular composition remains poorly characterized. This is largely because atmospheric particles contain a myriad of diverse organic compounds, not all of which extract in a single solvent or elute through a gas chromatograph; therefore, a substantial portion typically remains unanalyzed. Most often the chemical analysis is performed on a fraction that extracts in organic solvents such as benzene, ether or hexane; consequently, information on the molecular composition of the water-soluble fraction is particularly sparse and incomplete.This paper investigates theoretically the characteristics of the water-soluble fraction by splicing together various strands of information from the literature. We identify specific compounds that are likely to contribute to the water-soluble fraction by juxtaposing observations regarding the extraction characteristics and the molecular composition of atmospheric particulate organics with compound-specific solubility and condensibility for a wide variety of organics. The results show that water-soluble organics, which constitute a substantial fraction of the total organic mass, include C2 to C7 multifunctional compounds (e.g., diacids, polyols, amino acids). The importance of diacids is already recognized; our results provide an impetus for new experiments to establish the atmospheric concentrations and sources of polyols, amino acids and other oxygenated multifunctional compounds. 相似文献
32.
Anju Saxena Kamal Jeet Singh Christopher J. Cleal Shaila Chandra Shreerup Goswami Husain Shabbar 《Geological Journal》2019,54(4):2472-2494
Diverse macrofloral assemblages recovered from the Barakar, Raniganj, and Panchet formations of Tatapani–Ramkola Coalfield have been analysed. Plant fossils from nine localities represent typical Glossopteris floras of Permian age with Glossopteris as the dominant genus (33 species), whereas younger floral elements recorded from five locations are characterized by the presence of Triassic species, i.e., Glossopteris senii and G. gopadensis along with the genus Dicroidium. The complete flora includes 24 genera and 73 species. Three floristic assemblages identified on the basis of the macrofloras are the Barakar assemblage with 31 taxa, the Raniganj assemblage with 38 taxa, and the Panchet assemblage having 33 taxa. All the available data concerning megaplant remains, palynology, and petrology of this basin are reviewed and analysed to infer the diversity trends of Glossopteris flora through the sequence and its transformation at the Raniganj–Panchet boundary (?Permian/Triassic boundary) in this coalfield. The Barakar Formation has a moderate diversity of Glossopteris (18 species), which increases in Raniganj Formation (26 species) and declines in the Panchet Formation (16 species). There is a gradual upwards change in the taxonomic composition of the Raniganj assemblage, with a decline in diversity, although some typical Permian taxa (e.g., Paracalamites, Schizoneura, Dizeugotheca, Glossopteris, and Vertebraria) continued up to the Panchet Formation. In India, the continental Permian–Triassic boundary has been resolved mainly on the basis of palynomorph and macrofloral data and is conventionally taken to coincide with the boundary between the Raniganj and Panchet formations. The Raniganj–Panchet boundary has been tentatively proposed in one of the sections of this coalfield. At this boundary, the Glossopteris species typical of the Raniganj Formation (i.e., G. stenoneura and G. stricta) disappear. Some of the Glossopteridales taxa, continuing into the Panchet Formation, show relatively little discernable change from those found in the Raniganj Formation. The Panchet Formation exhibits a dominance of Dicroidium and also marks the appearance of ?Autunia, Heidiphyllum, Lepidopteris, Linguifolium, and Rissikia. Therefore, it is envisaged that plant life was only gradually transformed and evolved near this boundary, rather than being the subject of a comprehensive taxonomic turnover. The genus ?Autunia is reported for the first time from Indian Gondwana. 相似文献
33.
青川石英质玉是近年在四川省发现的新玉石矿。玉石矿体赋存于新元古界通木梁群太阳坪组云母石英片岩中。玉石的矿物成分主要为石英、铬云母、铬绢云母,具显微细粒粒状、片状变晶结构,片状、条带状构造。玉石种类分为绿色和白绿色,具油脂光泽;矿体规模大、块度好,玉石品质佳、可加工性强,可制作手镯、摆件、挂件、雕件等。根据野外地质工作判断,青川石英质玉属于区域变质成因,青川玉石矿的发现填补了四川石英质玉的空白,对丰富区域成矿系列和拓展区域玉石矿找矿方向具有重要意义。 相似文献
34.
Turbulent fluctuations of wind and temperature were measured using a three-component sonic anemometer at 8 m on a 30 m micro-meteorological tower erected at the Indian Institute of Technology (IIT) Kharagpur (22.3° N, 87.2° E), India, as part of the Monsoon Trough Boundary Layer Experiment (MONTBLEX). Diurnal and nocturnal variations of fluxes of sensible heat and momentum were estimated by the eddy correlation technique from 42 observations, each of 10 min duration during 6–8 July in the monsoon season of 1989. The estimated heat flux shows a diurnal trend while the momentum flux shows variability but no particular trend. The nocturnal heat flux changes sign intermittently.Fluctuations of vertical wind velocity
wand temperature when normalised with the respective scaling parameters u
*and * are found to scale with Z/L in accordance with the Monin-Obukhov similarity hypothesis: % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqOXdy2aaS% baaSqaaiaadEhaaeqaaOGaamiEaiaacIcacaWGAbGaai4laiaadYea% caGGPaWaaWbaaSqabeaacaaIXaGaai4laiaaiodaaaaaaa!3FE8!\[\phi _w x(Z/L)^{1/3} \], % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqOXdy2aaS% baaSqaaiabeI7aXbqabaGccaWG4bGaaiikaiaadQfacaGGVaGaamit% aiaacMcadaahaaWcbeqaaiaaigdacaGGVaGaaG4maaaaaaa!40A2!\[\phi _\theta x(Z/L)^{1/3} \] during unstable conditions and % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqOXdy2aaS% baaSqaaiaadEhaaeqaaOGaamiEaiaacIcacaWGAbGaai4laiaadYea% caGGPaaaaa!3D90!\[\phi _w x(Z/L)\], % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqOXdy2aaS% baaSqaaiabeI7aXbqabaGccaWG4bGaaiikaiaadQfacaGGVaGaamit% aiaacMcadaahaaWcbeqaaiabgkHiTiaaigdaaaaaaa!401F!\[\phi _\theta x(Z/L)^{ - 1} \] during stable conditions. Correlation coefficients for heat and momentum flux % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4SdC2aaS% baaSqaaiaadEhacqaH4oqCaeqaaaaa!3A71!\[\gamma _{w\theta } \] and
uwshow stability dependence. For unstable conditions, % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4SdC2aaS% baaSqaaiaadEhacqaH4oqCaeqaaaaa!3A71!\[\gamma _{w\theta } \] increases with increasing ¦Z/L¦ whereas
uwdecreases. During stable conditions, % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4SdC2aaS% baaSqaaiaadEhacqaH4oqCaeqaaaaa!3A71!\[\gamma _{w\theta } \] decreases with increasing Z/L while
uwdecreases very slowly from a value -0.36 to -0.37. 相似文献
35.
Geochemical studies on fifteen geothermal manifestations (38–70°C) from the Konkan coast geothermal province of India have been used to evaluate the reservoir temperatures. Activity studies of the minerals and the waters present in the reservoirs suggest that the thermal waters are in equilibrium with montmorillonite, kaolinite and quartz at about 100°C. Reservoir temperatures of these geothermal systems as estimated by geochemical thermometers, are 88 to 128°C, and thus too low for economic electricity production. 相似文献
36.
Laser-heated diamond anvil cell experiments at high pressure: Melting curve of nickel up to 700 kbar
Laser-heated experiments in a diamond anvil cell have been performed on high pressure melting of nickel up to 700 kbar. The laser heating system consists of diamond anvil cell, Nd:YAG and argon lasers, spectrograph with diode array, computer with software, CCD camera with monitor and optics. Experiments on melting of tungsten, nickel and platinum at 1 bar outside the diamond anvil cell and melting of nickel below 80 kbar in the cell were carried out to check the system for pressure and temperature measurements. The results show that for solid pressure medium the uncertainties in measurements of pressure at the experimental spot vary between ±5 kbar at 100 kbar and ±25 kbar at 660 kbar. Spectroradiometrically determined temperature is reliable within ±70 K. Melting was detected in situ by visual observation. The melting point of nickel at 660 kbar has been found to be 2557 ±66 K. 相似文献
37.
S. K. Saxena 《Contributions to Mineralogy and Petrology》1979,70(3):229-235
A garnet-clinopyroxene geothermometer based on the available experimental data on compositions of coexisting phases in the system MgO-FeO-MnO-Al2O3-Na2O-SiO2 is as follows: $$T({\text{}}K) = \frac{{8288 + 0.0276 P {\text{(bar)}} + Q1 - Q2}}{{1.987 \ln K_{\text{D}} + 2.4083}}$$ where P is pressure, and Q1, Q2, and K D are given by the following equations $$Q1 = 2,710{\text{(}}X_{{\text{Fe}}} - X_{{\text{Mg}}} {\text{)}} + 3,150{\text{ }}X_{{\text{Ca}}} + 2,600{\text{ }}X_{{\text{Mn}}} $$ (mole fractions in garnet) $$\begin{gathered}Q2 = - 6,594[X_{{\text{Fe}}} {\text{(}}X_{{\text{Fe}}} - 2X_{{\text{Mg}}} {\text{)]}} \hfill \\{\text{ }} - 12762{\text{ [}}X_{{\text{Fe}}} - X_{{\text{Mg}}} (1 - X_{{\text{Fe}}} {\text{)]}} \hfill \\{\text{ }} - 11,281[X_{{\text{Ca}}} (1 - X_{{\text{Al}}} ) - 2X_{{\text{Mg}}} 2X_{{\text{Ca}}} ] \hfill \\{\text{ + 6137[}}X_{{\text{Ca}}} (2X_{{\text{Mg}}} + X_{{\text{Al}}} )] \hfill \\{\text{ + 35,791[}}X_{{\text{Al}}} (1 - 2X_{{\text{Mg}}} )] \hfill \\{\text{ + 25,409[(}}X_{{\text{Ca}}} )^2 ] - 55,137[X_{{\text{Ca}}} (X_{{\text{Mg}}} - X_{{\text{Fe}}} )] \hfill \\{\text{ }} - 11,338[X_{{\text{Al}}} (X_{{\text{Fe}}} - X_{{\text{Mg}}} )] \hfill \\\end{gathered} $$ [mole fractions in clinopyroxene Mg = MgSiO3, Fe = FeSiO3, Ca = CaSiO3, Al = (Al2O3-Na2O)] K D = (Fe/Mg) in garnet/(Fe/Mg) in clinopyroxene. Mn and Cr in clinopyroxene, when present in small concentrations are added to Fe and Al respectively. Fe is total Fe2++Fe3+. 相似文献
38.
Narendra K. Saxena 《Marine Geophysical Researches》1984,7(1-2):277-282
The Subtropical Atlantic Climate Study (STACS) is a subprogram in the NOAA climate program designed to access the feasibility
of monitoring horizontal fluxes in the Gulf Stream system off Florida. Transport in the Florida Current fluctuates on time
scales which are reflected in sea level records monitored at tide gauges. Geodetic leveling, connecting tide gauges along
the east coast of the United States, allows intercomparison of sea level records alongstream, but the cross-stream and alongstream
records in the Bahamas and Cuba are not connected. In this study, various methods to determine absolute sea level differences
across the Straits of Florida between Miami, Florida and Cat Cay, Bahamas, a part of the STACS area, were investigated; the
desired accuracy of the sea level difference is ± 1 cm. This study indicates that a combination of dense gravity data with
satellite altimeter (TOPEX and GEOSAT) data in the STACS area could provide a ± 1 cm absolute sea level difference accuracy
across the Straits of Florida. This paper also provides discussion of other conventional methods. 相似文献
39.
P. P. Saxena 《Earth, Moon, and Planets》2010,106(2-4):113-118
In view of the possible production of formaldehyde and acetaldehyde in Titan’s atmosphere, the production of α-amino nitriles, the precursors of Glycine and Alanine amino acids, is explored in the upper atmosphere of Titan. The presence of Glycine and Alanine amino acids or their precursor amino nitriles can be used as a diagnostic, respectively for the presence or absence of water locally on the surface of Titan. 相似文献
40.
The problem of surveying watersheds for strategic planning in the Himalayan terrain has attracted the attention of the land surveyors recently. A small watershed in Surgad Catchment has been surveyed to select various parameters that determine soil loss, which can be studied using aerial photo-interpretation technique with a view to watershed management. Soil, slope, landuse and micro climatic factors have been used to delineate different morphogenetic categories. The result shows that on steeper slopes, well developed soils are found which indicates a high tolerance limits of these soils. In Himalayan terrain soils and vegetation are therefore, better indices of sediment losses than slopes. Small scale aerial photographs can be successfully used to judge the tolerance limits of soils in Himalayan terrain. 相似文献