Editorial: special issue on hot subdwarf stars     

Zhanwen Han  Simon Jeffery  Philipp Podsiadlowski  Michael A. Dopita 《Astrophysics and Space Science》2010,328(1-2):1-2

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Integral modeling and financial impact of the geothermal situation and power plant at Soultz-sous-Forêts     

Philipp Heidinger 《Comptes Rendus Geoscience》2010,342(7-8):626-635

The science about deep Enhanced Geothermal Systems (EGS) is still an emerging process and for further spreading economics is the key of the technology. To understand the financial situation, a program for economic evaluation was developed. This software (Euronaut) is completely modularized and considers all cash flows. Projects like an EGS are wrapped into tree-like structures. Based on the results which were gained at Soultz-sous-Forêts, two configurations were designed. The first EGS configuration consists of a simplified two well (doublet) system where the dependencies of all components (mainly the reservoir, wells, pumps and the heat-to-power conversion unit) are physically and economically linked together. The realization of these dependencies and their complex interactions enable a sensitivity analysis of the borehole depth and reservoir depth, respectively. As a result, depth dependent effective costs and revenues of an EGS plant with the geohydrological characteristics of Soultz-sous-Forêts are determined. As a future development, the second configuration will adapt the actual situation at Soultz-sous-Forêts with the individual features of all four wells (GPK1 – GPK4). Then, this model can be used for all kinds of sensitivity analyses to clarify the impact of certain components or to optimize the operation scheme; e.g. the flow rates.  相似文献   

Tracing groundwater nitrate sources in the Dakar suburban area: an isotopic multi‐tracer approach     

M. Diédhiou  S. Cissé Faye  O. C. Diouf  S. Faye  A. Faye  V. Re  S. Wohnlich  F. Wisotzky  U. Schulte  P. Maloszewski 《水文研究》2012,26(5):760-770

The Dakar region is a mega city with multiple contaminant sources from urban expansion as well as industrial and agricultural activities. The major part of the region is underlain by unconfined sandy aquifer, which is vulnerable to contaminants derived from human land use. At present, the contaminated groundwater which extends over a large area in the suburban zone of Thiaroye poses a threat to the future of this valuable resource, and more specifically, a health threat. This study focuses on nitrate pollution occurrences and associated processes using nitrate isotope data (¹⁵N_NO3, ¹⁸O_NO3) combined with environmental isotopic tracers (¹⁸O, ²H, and ³H). Samples from 36 wells were collected to determine the level, distribution, and sources of contamination in relation to land use. Results indicate that shallow groundwater in the urbanized area of Thiaroye shows distinct evidence of surface contamination with nitrate as much as 300 mg/l NO₃^?. In rural area not serviced by water supply distribution network, much higher NO₃^? contents were found in few wells due to household and livestock feedlots. In most groundwater samples δ¹⁵N values ranged from + 10 to + 22‰, indicative of predominantly human and animal wastes. This was confirmed by environmental isotope data which suggest a mixture of polluted recharge waters. By using the dual δ¹⁵N vs δ¹⁸O as well as δ¹⁵N vs NO₃^? approach, denitrification may occur to some extent but it is blurred by mixing with new infiltrated nitrates and cycling derived from continuous leaky septic system. Results suggest that nitrate contamination of the aquifer is a consequence of unregulated urbanisation (homemade latrines), continuing contaminant transfer in shallow water depth where aerobic conditions prevail. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Korrosion und Korrosionsschutz im Wasserfach – Fortschrittsbericht 1971/72     

H.-J. Philipp  G. Müller 《洁净——土壤、空气、水》1976,4(3):195-226

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Broad distribution of crystal-field environments for Nd<Superscript>3+</Superscript> in calcite     

S. H.?Withers  R. E.?PealeEmail author  A. F.?Schulte  G.?Braunstein  K. M.?Beck  W. P.?Hess  R. J.?Reeder 《Physics and Chemistry of Minerals》2003,30(7):440-448

Calcite crystals were grown from solution with single-crystal dimensions up to 3 mm and doped up to 0.1 at% with Nd³⁺ ions. Phase purity was verified by powder X-ray diffraction. The concentration of Nd³⁺ was measured by energy-dispersive spectrometry and Rutherford backscattering spectrometry. Micro X-ray fluorescence mapping of the calcite grains indicates uniform Nd distribution in as-grown crystal grains. X-ray absorption fine structure suggests that Nd³⁺ is substituted for Ca²⁺ with local lattice distortion. Temperature-dependent near-infrared spectroscopy of Nd³⁺ impurities in calcite reveals large inhomogeneous linewidths and smooth line profiles that are characteristic of glassy hosts, though the samples are well crystallized.  相似文献   

Electron microprobe dating of monazite substantiates ages of major geological events in the southern Brazilian shield   总被引：1，自引：0，他引：1  

Hugo Tickyj  Lo A. Hartmann  Marcos A. Z. Vasconcellos  Ruy P. Philipp  Marcus V. D. Remus 《Journal of South American Earth Sciences》2004,16(8):84

To obtain the chemical Th^*–Pb isochron ages and surface maps of monazite crystals in igneous and metamorphic rocks from the southern Brazilian Shield, we employ Th–U-total Pb dating by an electron probe microanalyzer. The ages of two Trans-Amazonian metamorphic events are given by a felsic, garnet-bearing granulite from the Santa Maria Chico granulitic complex. The age of the first event, at approximately 2.35 Ga, was obtained by surface mapping in a grain included in garnet. The dating of the second event, 1899±43 Ma, is in agreement with previous data obtained in zircon crystals with sensitive high-resolution ion microprobe. Other determinations belong to the Brasiliano cycle. In the São Gabriel block, an age of 643±129 Ma was obtained on monazite from a staurolite-garnet schist of the Cambaizinho Formation, whereas a staurolite-bearing schist from the Passo Feio complex yielded a 510±68 Ma age. Several units in the Dom Feliciano belt were dated, including the biotite-sillimanite gneisses of the Várzea do Capivarita complex (552±90 Ma), the sillimanite-garnet gneisses of Camboriú complex (565±77 Ma), the Três Figueiras granite (558±57 Ma), and the Plaza Itapema granite (545±55 Ma). The ages presented in this study, obtained through monazite chemical dating, are confirmed through comparison with previous data regarding zircon crystals from the same geological units.  相似文献   

Thiols in hydrothermal solution: standard partial molal properties and their role in the organic geochemistry of hydrothermal environments     

Mitchell D. Schulte  Karyn L. Rogers 《Geochimica et cosmochimica acta》2004,68(5):1087-1097

In order to assess the potential role of organic sulfur compounds in hydrothermal systems, we use recent advances in theoretical geochemistry to estimate the standard partial molal thermodynamic properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for aqueous straight-chain alkyl thiols. Thermodynamic properties are used to determine the potential for thiol formation in both modern and Archean hydrothermal systems. We conclude that organic sulfur compounds may hold the key to the organic chemistry that led to the origin of life in hydrothermal settings. These results may also explain the presence of sulfur in a number of biomolecules present in ancient thermophilic microorganisms.  相似文献   

Earthquakes in Switzerland and surrounding regions during 2005     

Nicolas Deichmann  Manfred Baer  Jochen Braunmiller  Stephan Husen  Donat F?h  Domenico Giardini  Philipp K?stli  Urs Kradolfer  Stefan Wiemer 《Eclogae Geologicae Helvetiae》2006,99(3):443-452

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Atmospheric circulation variability in the North-Atlantic-European area since the mid-seventeenth century     

J. Jacobeit  H. Wanner  J. Luterbacher  C. Beck  A. Philipp  K. Sturm 《Climate Dynamics》2003,20(4):431-352

Based on monthly mean sea level pressure grids objectively reconstructed by Luterbacher et al. variations of dynamical modes of the atmospheric circulation for January and July are described by novel indices for running 31-year periods between 1659 and 1999. These indices reflect the continuous evolution of the atmospheric circulation not only with regard to frequency changes of major dynamical modes but also in terms of internal changes within each mode concerning both dynamic (vorticity, intensity) and climatic properties (Central European temperature and precipitation during occurrence of each mode, respectively). Results indicate the great importance of within-mode variations: the zonal circulation mode in January, varying in frequency with long-term cycles, primarily changed its dynamic and climatic properties (towards higher indices) during the transition from the Little Ice Age to modern conditions between 1800 and 1930. Within the Russian High mode of January a change in preference from easterly to westerly patterns above Central Europe occurred around 1850. For July, a striking frequency maximum of the westerly mode at the end of the eighteenth century coincided with a period of marked summer warmth in Central Europe due to negative/positive deviations in vorticity/temperature during occurrence of this mode. The long-term evolution in July indicates a general increase of anticyclonic conditions strengthening during the last 50 years towards a unique phenomenon within the last centuries. The strong increase in the winter-time westerly circulation during the last decades, however, does not appear extraordinary in view of the low-frequency variations of this mode.  相似文献   

Possible Effects of Altered Growth Behaviour of Norway Spruce (Picea abies) on Carbon Accounting     

Rainer Joosten  Andreas Schulte 《Climatic change》2002,55(1-2):115-129

Implementing the Kyoto Protocol necessitates precise and practical inventory methods for estimating the carbon reservoir in forests. An analysis of the German state North Rhine-Westphalia forest inventory data showed enormous deviations from the yield tables of Wiedemann (1936, 1942). Specifically the ratio of height/diameter at breast height was up to 30% lower than in the yield tables, which indicated wider annual rings and a lower basic density. Such differences most likely pose consequences for the calculation of the amount of carbon in these forests. In this study the aboveground green weight, moisture and the carbon content of fifteen 46-year old Norway spruces (Picea abies) were measured, and two approaches for calculating the aboveground carbon content of trees were discussed: the common methodology of applying expansion and conversion factors as well as using optimized regression equations. The average expansion factor deviated approximately 1.2% from the yield tables of Grundner and Schwappach (1906). The wood density was 368 kg/m³ and within the European scope of 320–420 kg/m³ (Bosshard, 1984; Hakkila, 1989; Knigge and Schulz, 1966; Trendelenburg and Mayer-Wegelin, 1955). The woody carbon content was found to be 50.42%, which corresponded well with reference values of 50.3% (Bosshard, 1984) and 51.4% (Knigge and Schulz, 1966). However, the average percentage of crown material carbon content was 0.75% higher than in the tree boles. This study demonstrated that the most reliable methodology for calculating aboveground tree carbon was a power regression function, which calculated the growing stock volume, converting it directly into tree carbon content. The results deviated by less than 1.3% (R² = 0.99) from the measured tree carbon. Using volume expansion factors and factors of basic density and carbon percentage, as in Burschel et al. (1993), the calculated results diverged –3.7% from the measured outcome. The adapted form according to Fang et al. (2001) deviated –1.2% (R² = 0.63) and the form following Brown and Schroeder (1999) about –2.5% (R² = 0.61) from the measured carbon of the sample trees. However, coefficients of variation from 12% and 13% for the presented algorithm illustrated that in reality the calculated carbon of single trees could diverge considerably from the model results.  相似文献