Organic solids produced by electrical discharge in reducing atmospheres: Tholin molecular analysis     

B.N. Khare  Carl Sagan  John E. Zumberge  Deborah S. Sklarew  Bartholomew Nagy 《Icarus》1981,48(2):290-297

The complex dark brown solid of a class called tholins, produced on passage of an electrical discharge through a roughly equimolar mixture of methane and ammonia with 2.6% water vapor, is analyzed by vacuum pyrolysis followed by gas chromatography and mass spectrometry. Pyrolyzates include a wide range of aliphatic and aromatic nitriles, alkanes, aromatic hydrocarbons, pyrrole, and pyridine. This tholin is remarkably stable to 950°C. It and its degradation products are candidate constituents of planetary aerosols in the outer solar system and of the grains in the interstellar medium.  相似文献   

Genesis of some tertiary Indian coals from the chemical composition of ash – a statistical approach: Part 1     

Arpita Sharma  Ananya Saikia  Puja Khare  B P Baruah 《Journal of Earth System Science》2014,123(7):1705-1715

In the present investigation, 37 numbers of high sulphur tertiary coal samples from Meghalaya, India have been studied on the basis of proximate and ash analysis. Various statistical tools like Bivariant Analysis, Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA), and also the geochemical indicators were applied to determine the dominant detrital or authigenic affinity of the ash forming elements in these coals. The genetic interpretation of coal as well as the coal ash has been carried out based on chemical compositions of high temperature ash (HTA) by using Detrital/Authigenic Index. X-Ray Diffraction (XRD) analysis was also carried out to study the mineralogy of the studied coal ashes. Both statistical tools and geochemical indicators have confirmed the detrital nature of these coals as well as the ash forming elements.  相似文献   

Evaluating the performance of climate models in reproducing the hydrological characteristics of rainfall events     

Jung-Hun Song  Satbyeol Shin  Jaepil Cho  Rajendra Paudel  Yogesh P. Khare 《水文科学杂志》2020,65(9):1490-1511

ABSTRACT

Rainfall events largely control hydrological processes occurring on and in the ground, but the performance of climate models in reproducing rainfall events has not been investigated enough to guide selection among the models when making hydrological projections. We proposed to compare the durations, intensities, and pause periods, as well as depths of rainfall events when assessing the accuracy of general circulation models (GCMs) in reproducing the hydrological characteristics of observed rainfall. We also compared the sizes of design storm events and the frequency and severity of drought to demonstrate the consequences of GCM selection. The results show that rainfall and extreme hydrological event projections could significantly vary depending on climate model selection and weather stations, suggesting the need for a careful and comprehensive evaluation of GCM in the hydrological analysis of climate change. The proposed methods are expected to help to improve the accuracy of future hydrological projections for water resources planning.  相似文献   

Latitudinal trends in morphological characteristics of <Emphasis Type="Italic">Neogloboquadrina pachyderma</Emphasis> (Ehrenberg) along a north–south transect in the south-western Indian Ocean     

Neloy Khare  Pawan Govil  Abhijit Mazumder 《Geo-Marine Letters》2009,29(1):61-69

A total of 25 surficial sediment samples (Peterson grab, gravity and piston cores), collected during the Pilot Expedition to Southern Ocean (PESO) 2004 cruises 199C and 200 onboard the ORV Sagar Kanya along a N–S transect between 9.69°N and 55.01°S, and 80 and 40°E in the Indian Ocean sector of the Southern Ocean (SW Indian Ocean), have been investigated for various morphological features—test size, mean proloculus size and coiling direction (dextral/sinistral forms)—of the planktic indicator species Neogloboquadrina pachyderma (Ehrenberg). The results show that the coiling directions co-vary with temperature and salinity, the abundances of sinistrally coiled forms increasing towards higher latitudes (south of 40°S), whereas dextrally coiled forms show a reverse trend. Similarly, overall test and proloculus sizes depend largely on the physicochemical properties (salinity, temperature, nutrients, calcium saturation) of the ambient water masses. These observations suggest that, particularly at the boundaries between different water masses, variations in morphological features of N. pachyderma can meaningfully be used to reconstruct paleoceanographic conditions from Indian Ocean sediments.  相似文献