The Preparation and Preliminary Characterisation of Eight Geological MPI-DING Reference Glasses for In-Situ Microanalysis   总被引：13，自引：4，他引：9  

Klaus Peter Jochum  Donald B. Dingwell  Alexander Rocholl  Brigitte Stoll  Albrecht W. Hofmann  S. Becker  A. Besmehn  D. Bessette  H.-J. Dietze  P. Dulski  J. Erzinger  E. Hellebrand  P. Hoppe  I. Horn  K. Janssens  G.A. Jenner  M. Klein  W.F. McDonough  M. Maetz  K. Mezger  C. Müker  I.K. Nikogosian  C. Pickhardt  I. Raczek  D. Rhede  H.M. Seufert  S.G. Simakin  A.V. Sobolev  B. Spettel  S. Straub  L. Vincze  A. Wallianos  G. Weckwerth  S. Weyer  D. Wolf  M. Zimmer 《Geostandards and Geoanalytical Research》2000,24(1):87-133

Eight silicate glasses were prepared by directly fusing and stirring 50-100 g each of basalt, andesite, komatiite, peridotite, rhyolite, and quartz-diorite. These are referred to as MPI-DING glasses and were made for the purpose of providing reference materials for geochemical, in-situ microanalytical work. Results from various analytical techniques indicate that individual glass fragments are well homogenised with respect to major and trace elements at the μm to mm scale. Heterogeneities due to quench crystallisation of olivine have been observed in small and limited areas of the two komatiitic glasses. In order to obtain concentration values for as many elements as possible, the glasses were analysed by a variety of bulk and microanalytical methods in a number of laboratories. The analytical uncertainties of most elements are estimated to be between 1% and 10%. From the analytical data, preliminary reference values for more than sixty elements were calculated. The analytical uncertainties of most elements are estimated to be between 1% and 10%.  相似文献   

The Effectiveness of Arsenic Remediation from Groundwater in a Private Home     

Elizabeth Pratson  Avner Vengosh  Gary Dwyer  Lincoln Pratson  Emily Klein 《Ground Water Monitoring & Remediation》2010,30(1):87-93

Private wells are the source of drinking water for approximately 15% of households in the United States, but these wells are not regulated or monitored by government agencies. The well waters can contain arsenic, a known carcinogen that occurs in groundwater throughout the nation at concentrations that can exceed the Maximum Contaminant Level defined by the U.S. Environmental Protection Agency (10 ppb). In order to reduce arsenic exposure, homeowners can either rely on bottled water for drinking or install in-house water treatment systems for arsenic removal. Here, we document the arsenic levels associated with these options. We examined 24 different major bottled water brands and found that all have arsenic levels <1.5 parts per billion (ppb), and more than half have levels below our measurement detection limit of 0.005 ppb. For in-house treatment systems, we examined the performance of arsenic removal by point-of-use reverse osmosis filtration, and by whole-house and point-of-use filters containing granulated ferric oxide. Our results show that long-term (2 years) filtration with granulated ferric oxide reduced arsenic in well water from an initial concentration of 4 to 9 ppb down to <0.005 ppb, validating this technology as an effective form of arsenic remediation for private homes.  相似文献   

First detection of correlated electron beams and plasma jets in radio and soft X-ray data     

H. Aurass  K. -L. Klein  P. C. H. Martens 《Solar physics》1994,155(1):203-206

From a common analysis of solar radio spectral and imaging data of a fast drift burst of type U(N) together with Yohkoh soft X-ray images it is shown that the radio emission is compatible with electron beams injected and reflected in extended loops. The electron beam production coincides with the injection of hot matter, visible as a jetlike soft X-ray feature in the underlying loop system.  相似文献   

Stable nickel isotopes and cosmogenic beryllium-10 and aluminum-26 in metallic spheroids from Meteor Crater,Arizona     

S. Xue  G. F. Herzog  G. S. Hall  J. Klein  R. Middleton  D. Juenemann 《Meteoritics & planetary science》1995,30(3):303-310

Abstract— The isotopic abundances of Ni in 17 metallic spheroids from Meteor Crater, Arizona, were determined by inductively coupled plasma mass spectrometry (ICP-MS). Sixteen spheroids have normal isotopic abundances. A 17th shows a marginally detectable mass fractionation of 0.40 ± 0.14 %/AMU in favor of the heavier isotopes. The general absence of mass fractionation indicates that open system evaporation caused little loss of Ni. Variable activities of the cosmogenic radionuclides ¹⁰Be and ²⁶Al were measured by accelerator mass spectrometry in separate suites of spheroids. Activities of ²⁶Al in most samples and of ¹⁰Be in metal cores separated from spheroids indicate that they either (1) come from greater depths in the parent meteoroid than do hand specimens, or (2) lost Al and Be during the process of spheroid formation. One individual spheroid has ¹⁰Be and ²⁶Al activities comparable to those of bulk specimens. This result suggests that spheroid formation may occasionally include material from the outermost meter or so of the impactor. Relatively high activities of ¹⁰Be, ～3 dpm/kg, in the siliceous shells of Canyon Diablo spheroids very likely have a meteoric origin.  相似文献   

Exposure history of glass and breccia phases of lunar meteorite EET87521     

O. Eugster  Ch. Thalmann  A. Albrecht  G. F. Herzog  J. S. Delaney  J. Klein  R. Middleton 《Meteoritics & planetary science》1996,31(2):299-304

Abstract— Glass-rich separates were prepared from a sample of the basaltic lunar meteorite EET87521 rich in dark glass. Noble gas isotopic abundances and ²⁶Al and ¹⁰Be activities were measured to find out whether shock effects associated with lunar launch helped to assemble these phases. Similar ¹⁰Be and ²⁶Al activities indicate that all materials in EET87521 had a common exposure history in the last few million years before launch. However, the glass contains much higher concentrations of trapped gases and records a much longer cosmic-ray exposure, 100 Ma–150 Ma, in the lunar regolith than does the bulk sample. The different histories show that the glass existed long before the ejection of EET87521. The trapped ⁴⁰Ar/³⁶Ar ratio of 1.6 ± 0.1 implies that the lunar exposure that produced most of the stable cosmogenic noble gases began 500 Ma ago. Cosmogenic and trapped noble gas components correlate strongly in various temperature-release fractions and phases of EET87521, which is probably because the glass contains most of the gas. The trapped solar ratios, ²⁰Ne/²²Ne = 12.68 ± 0.20 and ³⁶Ar/³⁸Ar = 5.24 ± 0.05 can be understood as resulting from a mixture consisting of ～60% solar wind and 40% solar energetic particles (SEP). All EET87521 phases show a ⁴⁰K-⁴⁰Ar gas retention age of ～3300 Ma, which is in the range of typical lunar mare basalts.  相似文献   

Acceleration of cosmic-ray electrons by large-scale galactic spiral shocks — An observational report     

M. Urbanik  R. Beck  U. Klein  R. Gräve 《Astrophysics and Space Science》1989,156(1-2):195-198

The hypothesis that large-scale shocks accompanying spiral density waves are the main sources of cosmic-ray electrons for whole galactic disks has been tested utilizing results of 10.7 GHz observations of spiral galaxies. It is suggested that the 10.7 GHz emission of galactic disks is largely controlled by star-forming processes, and that large-scale shocks apparently play a minor role.  相似文献   

Stress transfer in earthquakes, hazard estimation and ensemble forecasting: Inferences from numerical simulations     

John B. Rundle  Paul B. Rundle  Andrea Donnellan  P. Li  W. Klein  Gleb Morein  D.L. Turcotte  Lisa Grant   《Tectonophysics》2006,413(1-2):109

Observations indicate that earthquake faults occur in topologically complex, multi-scale networks driven by plate tectonic forces. We present realistic numerical simulations, involving data-mining, pattern recognition, theoretical analyses and ensemble forecasting techniques, to understand how the observable space–time earthquake patterns are related to the fundamentally inaccessible and unobservable dynamics. Numerical simulations can also help us to understand how the different scales involved in earthquake physics interact and influence the resulting dynamics. Our simulations indicate that elastic interactions (stress transfer) combined with the nonlinearity in the frictional failure threshold law lead to the self-organization of the statistical dynamics, producing 1) statistical distributions for magnitudes and frequencies of earthquakes that have characteristics similar to those possessed by the Gutenberg–Richter magnitude–frequency distributions observed in nature; and 2) clear examples of stress transfer among fault activity described by stress shadows, in which an earthquake on one group of faults reduces the Coulomb failure stress on other faults, thereby delaying activity on those faults. In this paper, we describe the current state of modeling and simulation efforts for Virtual California, a model for all the major active strike slip faults in California. Noting that the Working Group on California Earthquake Probabilities (WGCEP) uses statistical distributions to produce earthquake forecast probabilities, we demonstrate that Virtual California provides a powerful tool for testing the applicability and reliability of the WGCEP statistical methods. Furthermore, we show how the simulations can be used to develop statistical earthquake forecasting techniques that are complementary to the methods used by the WGCEP, but improve upon those methods in a number of important ways. In doing so, we distinguish between the “official” forecasts of the WGCEP, and the “research-quality” forecasts that we discuss here. Finally, we provide a brief discussion of future problems and issues related to the development of ensemble earthquake hazard estimation and forecasting techniques.  相似文献   

Dissolved material transport—the flushing effect in surface and subsurface flow     

M. Klein 《地球表面变化过程与地形》1981,6(2):173-178

The study deals with the relationship between specific conductance and water flow in a small catchment. Three flow types were studied: (a) channel flow; (b) overland flow; (c) subsurface flow. The study of the three flow types demonstrates the important role of the flushing effect in small basins. The flushing effect is seen as an increase in water conductivity in the early stage of an event. Flushing is probably a function of accumulation in the basin. Accumulation is best defined as a function of time elapsing since the last heavy rain. The study has been carried out in the School of Geography at Leeds University, Leeds LS2 9JT, England.  相似文献   

On the call for issue advocates,or what it takes to make adaptation research useful     

Anna Bohman  Erik Glaas  Johannes Klein  Mia Landauer  Tina-Simone Neset  Björn-Ola Linnér  Sirkku Juhola 《Climatic change》2018,149(2):121-129

This essay discusses the concept of usefulness of research for climate change adaptation. Based on prior research and stakeholder interactions with policymakers and practitioners in the Nordic countries, we contend that critical issues related to the usefulness of adaptation research seem less associated with content (i.e. research outputs), but rather centre around the efforts made to design and communicate research, that is, to put research at the service of society and make the case for adaptation on the political agenda. This, we argue, to some extent mirrors the situation and political context in the Nordic countries, where adaptation in many locations still is an issue in its infancy, not firmly established on the political agendas, and where working procedures are not yet institutionally settled. In this context, science is considered and sometimes used as a discursive tool to make the case for adaptation. Based on the calls for research that inspires, raises hope and helps to raise the issue of adaptation on the political agendas, we elaborate the role of honest issue advocates for researchers in the field of adaptation science.  相似文献   

On the relationship between vegetation and climate in tropical and northern Africa     

Martin Schmidt  Doris Klein  Christopher Conrad  Stefan Dech  Heiko Paeth 《Theoretical and Applied Climatology》2014,115(1-2):341-353

Vegetation cover is a crucial component of the Earth’s climate system but, still, our understanding of the mechanisms governing the reciprocal influence between atmosphere and vegetation is limited. In this study, we investigate the unilateral atmospheric impact on vegetation cover in tropical and northern Africa, differentiated into regions with different circulation regimes and into detailed land-cover classes. In contrast to former studies, climate predictors from a regional climate model are used as input for a multiple regression model. Climate models provide consistent data without gaps at high spatial resolution, a considerably larger set of available climate variables and the perspective to transfer the statistical relationships to future projections, e.g., in the context of anthropogenic climate change. Indeed, robust climate predictors which drive up to 70 % of observed interannual vegetation variability could be extracted from the climate model. Besides precipitation and temperature, global radiation, and relative humidity play an important role. The statistical transfer functions are plausible in terms of the affected regions and land-cover classes and draw a rather complex picture of the atmosphere–vegetation relation in Africa.  相似文献