Loss on ignition as a method for estimating organic and carbonate content in sediments: reproducibility and comparability of results   总被引：59，自引：0，他引：59  

Oliver Heiri  André F. Lotter  Gerry Lemcke 《Journal of Paleolimnology》2001,25(1):101-110

Five test runs were performed to assess possible bias when performing the loss on ignition (LOI) method to estimate organic matter and carbonate content of lake sediments. An accurate and stable weight loss was achieved after 2 h of burning pure CaCO₃ at 950 °C, whereas LOI of pure graphite at 530 °C showed a direct relation to sample size and exposure time, with only 40-70% of the possible weight loss reached after 2 h of exposure and smaller samples losing weight faster than larger ones. Experiments with a standardised lake sediment revealed a strong initial weight loss at 550 °C, but samples continued to lose weight at a slow rate at exposure of up to 64 h, which was likely the effect of loss of volatile salts, structural water of clay minerals or metal oxides, or of inorganic carbon after the initial burning of organic matter. A further test-run revealed that at 550 °C samples in the centre of the furnace lost more weight than marginal samples. At 950 °C this pattern was still apparent but the differences became negligible. Again, LOI was dependent on sample size.An analytical LOI quality control experiment including ten different laboratories was carried out using each laboratory's own LOI procedure as well as a standardised LOI procedure to analyse three different sediments. The range of LOI values between laboratories measured at 550 °C was generally larger when each laboratory used its own method than when using the standard method. This was similar for 950 °C, although the range of values tended to be smaller. The within-laboratory range of LOI measurements for a given sediment was generally small. Comparisons of the results of the individual and the standardised method suggest that there is a laboratory-specific pattern in the results, probably due to differences in laboratory equipment and/or handling that could not be eliminated by standardising the LOI procedure.Factors such as sample size, exposure time, position of samples in the furnace and the laboratory measuring affected LOI results, with LOI at 550 °C being more susceptible to these factors than LOI at 950 °C. We, therefore, recommend analysts to be consistent in the LOI method used in relation to the ignition temperatures, exposure times, and the sample size and to include information on these three parameters when referring to the method.  相似文献   

Markov chain Monte Carlo methods for conditioning a permeability field to pressure data   总被引：3，自引：0，他引：3  

Dean S. Oliver  Luciane B. Cunha  Albert C. Reynolds 《Mathematical Geology》1997,29(1):61-91

Generating one realization of a random permeability field that is consistent with observed pressure data and a known variogram model is not a difficult problem. If, however, one wants to investigate the uncertainty of reservior behavior, one must generate a large number of realizations and ensure that the distribution of realizations properly reflects the uncertainty in reservoir properties. The most widely used method for conditioning permeability fields to production data has been the method of simulated annealing, in which practitioners attempt to minimize the difference between the ’ ’true and simulated production data, and “true” and simulated variograms. Unfortunately, the meaning of the resulting realization is not clear and the method can be extremely slow. In this paper, we present an alternative approach to generating realizations that are conditional to pressure data, focusing on the distribution of realizations and on the efficiency of the method. Under certain conditions that can be verified easily, the Markov chain Monte Carlo method is known to produce states whose frequencies of appearance correspond to a given probability distribution, so we use this method to generate the realizations. To make the method more efficient, we perturb the states in such a way that the variogram is satisfied automatically and the pressure data are approximately matched at every step. These perturbations make use of sensitivity coefficients calculated from the reservoir simulator.  相似文献   

Calculations of the seasonal loadings of North Sea sediments with persistent aromatic organochlorines     

Dipl. Ing. Dr. Rainer Knickmeyer  Staatl. gepr. Lebensmittelchem. Oliver Landgraff  Prof. Dr. Hans Steinhart 《Ocean Dynamics》1990,43(6):289-309

The content and distribution of ΣPCB (as the sum of 24 individual components), HCB and p,p′-DDE was determined in sediments taken from the North Sea during two seasons. The mass-balance of aromatic organochlorine compounds in the upper 2 cm of sediments is calculated and dicussed in relation to pollutant dispersal.  相似文献   

Analysis of the Behavior of Sedimentary Rocks Under Impact Loading     

Oliver Millon  Maria Luisa Ruiz-Ripoll  Tobias Hoerth 《Rock Mechanics and Rock Engineering》2016,49(11):4257-4272

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Promoting green industrial development through local content requirements: India's National Solar Mission     

Oliver Johnson 《Climate Policy》2016,16(2):178-195

In order to make renewable energy technology deployment strategies politically acceptable, many countries are linking them to other socio-economic goals. A controversial industrial policy tool that is increasingly popular is the use of local content requirements (LCRs). These regulate the extent to which certain projects must use local products and are often justified on the basis of supporting local employment and private sector development. The LCR debate has centred on the rights and wrongs of protecting infant industry, with little progress being made in finding common ground. This article aims to move beyond this stalemate to understand conditions under which LCRs might be an effective tool for promoting local manufacturing. To do so, an effectiveness framework is applied to LCRs for solar photovoltaics in India's National Solar Mission. The article finds that for LCRs to be effective, they must be (1) limited in duration and incorporate planned evaluation phases, (2) focused on technologies and components for which technical expertise is available and global market entry barriers are manageable, and (3) linked to training and promotion of business linkages and linked to support for other stages of the value chain and wider services integral to success of renewable energy industries.

Policy relevance

It is widely appreciated that governments need to support renewable energy technology deployment in order to mitigate climate change. However, policy makers face increasing pressure to link such support with other socio-economic goals, such as job creation, economic development, and poverty reduction. One such policy support mechanism is the use of local content requirements (LCRs) linked to feed-in tariffs. Policy makers are faced with a difficult choice as manufacturing interest groups lobby for the establishment of protection measures such as LCRs whilst the international trade community led by the World Trade Organization (WTO) seeks to limit their use. This difficulty is amplified by the limited information on the impact of LCRs on job creation and economic development. In this context, this article documents the use of LCRs in India's National Solar Mission and seeks to understand the conditions under which LCRs are an effective policy tool for building a competitive local manufacturing industry.  相似文献   

Stratigraphy and palaeoecology of the Upper Marine Molasse (OMM) of the central Swiss Plateau     

Jürg Jost  Oliver Kempf  Daniel Kälin 《Swiss Journal of Geoscience》2016,109(2):149-169

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A study on the dependency of GNSS pseudorange biases on correlator spacing   总被引：2，自引：0，他引：2  

André Hauschild  Oliver Montenbruck 《GPS Solutions》2016,20(2):159-171

We provide a comprehensive overview of pseudorange biases and their dependency on receiver front-end bandwidth and correlator design. Differences in the chip shape distortions among GNSS satellites are the cause of individual pseudorange biases. The different biases must be corrected for in a number of applications, such as positioning with mixed signals or PPP with ambiguity resolution. Current state-of-the-art is to split the pseudorange bias into a receiver- and a satellite-dependent part. As soon as different receivers with different front-end bandwidths or correlator designs are involved, the satellite biases differ between the receivers and this separation is no longer practicable. A test with a special receiver firmware, which allows tracking a satellite with a range of different correlator spacings, has been conducted with live signals as well as a signal simulator. In addition, the variability of satellite biases is assessed through zero-baseline tests with different GNSS receivers using live satellite signals. The receivers are operated with different settings for multipath mitigation, and the changes in the satellite-dependent biases depending on the receivers’ configuration are observed.  相似文献   

Fault‐controlled fluid flow inferred from hydrothermal vents imaged in 3D seismic reflection data,offshore NW Australia          下载免费PDF全文

Craig Magee  Oliver B. Duffy  Kirsty Purnell  Rebecca E. Bell  Christopher A.‐L. Jackson  Matthew T. Reeve 《Basin Research》2016,28(3):299-318

Fluid migration pathways in the subsurface are heavily influenced by pre‐existing faults. Although studies of active fluid‐escape structures can provide insights into the relationships between faults and fluid flow, they cannot fully constrain the geometry of and controls on the contemporaneous subsurface fluid flow pathways. We use 3D seismic reflection data from offshore NW Australia to map 121 ancient hydrothermal vents, likely related to magmatic activity, and a normal fault array considered to form fluid pathways. The buried vents consist of craters up to 264 m deep, which host a mound of disaggregated sedimentary material up to 518 m thick. There is a correlation between vent alignment and underlying fault traces. Seismic‐stratigraphic observations and fault kinematic analyses reveal that the vents were emplaced on an intra‐Tithonian seabed in response to the explosive release of fluids hosted within the fault array. We speculate that during the Late Jurassic the convex‐upwards morphology of the upper tip‐lines of individual faults acted to channelize ascending fluids and control where fluid expulsion and vent formation occurred. This contribution highlights the usefulness of 3D seismic reflection data to constraining normal fault‐controlled subsurface fluid flow.  相似文献   

The Price of Journals in Geography     

Oliver T. Coomes  Tim R. Moore  Sébastien Breau 《The Professional geographer》2017,69(2):251-262

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An Air Mass Evaluation Of The Concept Of Continentality     

John E. Oliver 《The Professional geographer》1970,22(2):83-87

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