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Sulphur Content (sulphur + content)
Selected AbstractsGEOCHEMICAL AND GEOPHYSICAL ANOMALIES AT THE ZDANICE OIL- AND GASFIELD, SE CZECH REPUBLICJOURNAL OF PETROLEUM GEOLOGY, Issue 1 2008M. Matolin Oil at the Zdanice field in the SE Czech Republic is reservoired at a depth of 900 m in weathered Precambrian granitoids and Lower Miocene sandstones and conglomerates. Tertiary claystones, siltstones and sandstones form the top seal. Surface gamma-ray spectrometry carried out along two profiles across the field (6,880 m and 8,335 m in length, respectively) found perceptible decreases of K, U, and Th concentrations relative to background values. This can be explained in terms of enhanced leaching of these radionuclides by groundwater acids derived from hydrocarbons. Observed increases in radon and thoron in soil gas above the oil-producing zone at Zdanice may be caused by enhanced gas emanation from U- and Th-bearing minerals decomposed by groundwater acids. Laboratory analyses of 444 samples collected from 18 shallow boreholes (20 m deep) pointed to a trend of decreasing K, U and Th concentrations above the oil-producing zone at Zdanice. Decreases in rock porosity and organic carbon content were also noted together with an increase in mineralogical density, magnetic susceptibility and sulphur content. Petrophysical analyses of 330 samples from deep boreholes showed lower values of K and U in samples from oil-producing wells. These observations of minor petrophysical alterations in rocks overlying the Zdanice oilfield may be characteristic and may be applicable to hydrocarbon exploration operations elsewhere. [source] New model calculations for the production rates of cosmogenic nuclides in iron meteoritesMETEORITICS & PLANETARY SCIENCE, Issue 4 2009Katja AMMON The model usually describes the production rates for cosmogenic radionuclides within their uncertainties; exceptions are 53Mn and 60Fe, possibly due to normalization problems. When an average S content of about 1 ± 0.5% is assumed for Grant and Carbo samples, which is consistent with our earlier study, the model predictions for 3He, 21Ne, and 38Ar are in agreement. For 4He the model has to be adjusted by 24%, possibly a result of our rather crude approximation for the primary galactic , particles. For reasons not yet understood the modeled 36Ar/38Ar ratio is about 30,40% higher than the ratio typically measured in iron meteorites. Currently, the only reasonable explanation for this discrepancy is the lack of experimentally determined neutron induced cross sections and therefore the uncertainties of the model itself. However, the new model predictions, though not yet perfect, enable determining the radius of the meteoroid, the exposure age, the sulphur content of the studied sample as well as the terrestrial residence time. The determination of exposure ages is of special interest because of the still open question whether the GCR was constant over long time scales. Therefore we will discuss in detail the differences between exposure ages determined with different cosmogenic nuclides. With the new model we can calculate exposure ages that are based on the production rates (cm3STP/(gMa)) of noble gases only. These exposure ages, referred to as noble gas exposure ages or simply 3,4He, 21Ne, or 36,38Ar ages, are calculated assuming the current GCR flux. Besides calculating noble gas ages we were also able to improve the 41K- 40K-and the 36Cl- 36Ar dating methods with the new model. Note that we distinguish between 36Ar ages (calculated via 36Ar production rates only) and 36Cl- 36Ar ages. Exposure ages for Grant and Carbo, calculated with the revised 41K- 40K method, are 628 ± 30 Ma and 841 ± 19 Ma, respectively. For Grant this is equal to the ages obtained using 3He, 21Ne, and 38Ar but higher than the 36Ar- and 36Cl- 36Ar ages by ,30%. For Carbo the 41K- 40K age is ,40% lower than the ages obtained using 3He, 21Ne, and 38Ar but equal to the 36Ar age. These differences can either be explained by our still insufficient knowledge of the neutron-induced cross sections or by a long-term variation of the GCR. [source] US braces itself for gasoline and diesel shortagesOIL AND ENERGY TRENDS, Issue 3 2006Article first published online: 9 MAR 200 New fuel regulations that are progressively being introduced in the US from the beginning of this year are likely to lead to radical changes in the gasoline and diesel fuel markets. The main change for gasoline is the replacement of methyl tertiary butyl ether (MTBE) by ethanol, whilst for diesel the principal development is the reduction in the permitted sulphur content. A shortage of the new fuels could increase price volatility and drive up prices. This is not a pleasant prospect for the White House, already under criticism for another energy plan: to cut imports of crude oil from the Middle East. [source] Hair interior defect in AKR/J miceCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 4 2009K. A. Giehl Summary Background., All AKR/J mice have a subtle defect that involves malformation of the central portion of hair fibres that is best visualized under white and polarized light microscopy. Aims., This study sought to characterize the clinical and ultrastructural features of the hair interior defect (HID) phenotype and to determine the chromosomal localization of the hid mutant gene locus. Methods., White and polarized light microscopy combined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the HID phenotype. Complementation testing and gene-linkage studies were performed to map the locus. Results., Using SEM, the hair-fibre structure on the surface was found to be similar to hairs obtained from normal BALB/cByJ+/+and C57BL/6 J+/+mice. There were also no differences in sulphur content. TEM revealed degenerative changes in the medulla similar to that seen by light microscopy. This autosomal recessive mutation is called HID (locus symbol: hid). We mapped the hid locus to the distal end of mouse chromosome 1. No genes reported to cause skin or hair abnormalities are known to be within this interval except for the lamin B receptor (Lbr), which had been excluded previously as the cause of the hid phenotype in AKR/J mice. Conclusion., A potentially novel gene or known gene with a novel phenotype resides within this interval, which may shed light on human diseases with defects in the inner structure of the hair fibre. [source] Sulphur, thiols, and disulphides in the fish epidermis, with remarks on keratinizationJOURNAL OF FISH BIOLOGY, Issue 4 2007W. Meyer Energy dispersive x-ray (EDX) analysis and qualitative and quantitative histochemistry were applied to study the distribution and contents of sulphur, thiols and disulphides in the epidermis of the river lamprey Lampetra fluviatilis, the lesser spotted dogfish Scyliorhinus canicula and the brown trout Salmo trutta fario. Thiols generally reacted weakly throughout the entire epidermis, whereas disulphide reactions were more distinct and differentiated. In the river lamprey, the concentrations of -S-S- groups clearly increased in the developing mucous cells from the stratum basale to the stratum superficiale; skein cells and granular cells reacted negatively to weakly. In the lesser spotted dogfish, amounts of disulphides appeared at moderate concentrations, and only goblet cells displayed a strong reaction. In the brown trout, filament cells showed low concentrations or weak reactions of disulphides, goblet cells and the most outer superficial cells stained strongly. Sulphur distribution and contents generally supported the histochemical observations in normal epidermis cells (absolute sulphur contents: 41,59 mM), only the brown trout showed high amounts of sulphur in the stratum basale (81 mM). The findings corroborate the view that there is an inverse correlation between keratinization and mucous secretion in normal fish epidermis. The sometimes distinct contents of disulphides in the outer mucous layer indicate that this system could endure higher mechanical stress than predictable from its large amounts of neutral glycoproteins. [source] VARIATIONS IN COMPOSITION, PETROLEUM POTENTIAL AND KINETICS OF ORDOVICIAN , MIOCENE TYPE I AND TYPE I-II SOURCE ROCKS (OIL SHALES): IMPLICATIONS FOR HYDROCARBON GENERATION CHARACTERISTICSJOURNAL OF PETROLEUM GEOLOGY, Issue 1 2010H. I. Petersen Lacustrine and marine oil shales with Type I and Type I-II kerogen constitute significant petroleum source rocks around the world. Contrary to common belief, such rocks show considerable compositional variability which influences their hydrocarbon generation characteristics. A global set of 23 Ordovician , Miocene freshwater and brackish water lacustrine and marine oil shales has been studied with regard to their organic composition, petroleum potential and generation kinetics. In addition their petroleum generation characteristics have been modelled. The oil shales can be classified as lacosite, torbanite, tasmanite and kukersite. They are thermally immature. Most of the shales contain >10 wt% TOC and the highest sulphur contents are recorded in the brackish water and marine oil shales. The kerogen is sapropelic and is principally composed of a complex of algal-derived organic matter in the form of: (i) telalginite (Botryococcus-, Prasinophyte- (Tasmanites?) or Gloeocapsomorpha-type); (ii) lamalginite (laminated, filamentous or network structure derived from Pediastrum- or Tetraedron-type algae, from dinoflagellate/acritarch cysts or from thin-walled Prasinophyte-type algae); (iii) fluorescing amorphous organic matter (AOM) and (iv) liptodetrinite. High atomic H/C ratios reflect the hydrogen-rich Type I and Type I-II kerogen, and Hydrogen Index values generally >300 mg HC/g TOC and reaching nearly 800 mg HC/g TOC emphasise the oil-prone nature of the oil shales. The kerogen type and source rock quality appear not to be related to age, depositional environment or oil shale type. Therefore, a unique, global activation energy (Ea) distribution and frequency factor (A) for these source rocks cannot be expected. The differences in kerogen composition result in considerable variations in Ea -distributions and A-factors. Generation modelling using custom kinetics and the known subsidence history of the Malay-Cho Thu Basin (Gulf of Thailand/South China Sea), combined with established and hypothetical temperature histories, show that the oil shales decompose at different rates during maturation. At a maximum temperature of ,120°C reached during burial, only limited kerogen conversion has taken place. However, oil shales characterised by broader Ea -distributions with low Ea -values (and a single approximated A-factor) show increased decomposition rates. Where more deeply buried (maximum temperature ,150°C), some of the brackish water and marine oil shales have realised the major part of their generation potential, whereas the freshwater oil shales and other brackish water oil shales are only ,30,40% converted. At still higher temperatures between ,165°C and 180°C all oil shales reach 90% conversion. Most hydrocarbons from these source rocks will be generated within narrow oil windows (,20,80% kerogen conversion). Although the brackish water and marine oil shales appear to decompose faster than the freshwater oil shales, this suggests that with increasing heatflow the influence of kerogen heterogeneity on modelling of hydrocarbon generation declines. It may thus be critical to understand the organic facies of Type I and Type I-II source rocks, particularly in basins with moderate heatflows and restricted burial depths. Measurement of custom kinetics is recommended, if possible, to increase the accuracy of any computed hydrocarbon generation models. [source] | ||||||||||