Determination of the Concentration of Carbonic Species in Natural Waters: Results from a World‐Wide Proficiency Test          下载免费PDF全文

Mahendra P. Verma  Enrique Portugal  Sophie Gangloff  María Aurora Armienta  Dornadula Chandrasekharam  Mayela Sanchez  Roberto E. Renderos  Miguel Juanco  Robert van Geldern 《Geostandards and Geoanalytical Research》2015,39(2):233-255

The results of an international interlaboratory proficiency test for the determination of carbonic species are presented. Eight laboratories analysed twelve water samples (four synthetic waters, one lake water, four geothermal waters, one seawater and two petroleum waters) by two methods: (a) individual laboratory analytical procedure and (b) acid–base titration curves in tabular form following a standardised protocol. In case (b), the concentrations of carbonic species were calculated by the organiser using the (1) Hydrologists' method, (2) Geochemists' method and/or (3) initial pH and total alkalinity method. For synthetic waters, the averaged % trueness and precision of measurement of the two methods were (trueness = 7.6, precision = 9.4) and (9.0, 3.4) for total alkalinity, and (6.6, 31.0) and (7.8, 6.1) for carbonic alkalinity, respectively. This indicates that the total alkalinity calculation procedure is in general correct in the individual laboratory method, but the carbonic alkalinity calculation procedure has serious problems. The measurements of total alkalinity for lake and seawaters were in agreement in both the methods; however, the individual laboratory measurement method for geothermal and petroleum waters was conceptually incorrect. Thus, the analytical procedures for the determination of carbonic species were reviewed. To apply the Hydrologists' and/or Geochemists' methods, the location of NaHCO₃EP and H₂CO₃EP is necessary, even for samples with pH lower than that of NaHCO₃EP, and a backward titration curve after complete removal of CO₂ must be performed. The initial pH and total alkalinity method is appropriate where a complete analysis of species that contribute to the alkalinity is known.  相似文献   

中国有壳变形虫Argynnia(Vucetich,1974)属的修订及若干环境重建问题探讨     

秦养民  张文静  李鸿凯  Enrique Lara  张千帆  朱荣  顾延生 《第四纪研究》2011,31(6):1060-1066

有壳变形虫是一类具外壳的陆相淡水根足纲(Rhizopoda)原生动物,广泛栖息于湖泊、泥炭、沼泽、土壤等各种淡水潮湿环境,由于其壳体具有很好的抗腐蚀性而在沉积物中保存下来,近年来广泛应用于泥炭和湖泊湿地的古环境重建研究中.大部分有壳变形虫是世界广泛分布的,但是也有一些种类具有一定的地带性分布格局.形态学和分子生物学的研...  相似文献   

Trade-offs associated with different modeling approaches for assessment of fish and shellfish responses to climate change     

Anne Babcock Hollowed  Enrique N. Curchitser  Charles A. Stock  Chang Ik Zhang 《Climatic change》2013,119(1):111-129

Considerable progress has been made in integrating carbon, nutrient, phytoplankton and zooplankton dynamics into global-scale physical climate models. Scientists are exploring ways to extend the resolution of the biosphere within these Earth system models (ESMs) to include impacts on global distribution and abundance of commercially exploited fish and shellfish. This paper compares different methods for modeling fish and shellfish responses to climate change on global and regional scales. Several different modeling approaches are considered including: direct applications of ESM’s, use of ESM output for estimation of shifts in bioclimatic windows, using ESM outputs to force single- and multi-species stock projection models, and using ESM and physical climate model outputs to force regional bio-physical models of varying complexity and mechanistic resolution. We evaluate the utility of each of these modeling approaches in addressing nine key questions relevant to climate change impacts on living marine resources. No single modeling approach was capable of fully addressing each question. A blend of highly mechanistic and less computationally intensive methods is recommended to gain mechanistic insights and to identify model uncertainties.  相似文献   

The extragalactic submillimetre population: predictions for the SCUBA Half-Degree Extragalactic Survey (SHADES)     

Eelco van Kampen  Will J. Percival  Miller Crawford  James S. Dunlop  Susie E. Scott  Neil Bevis  Seb Oliver  Frazer Pearce  Scott T. Kay  Enrique Gaztañaga  David H. Hughes  Itziar Aretxaga 《Monthly notices of the Royal Astronomical Society》2005,359(2):469-480

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New light on dark cosmos     

Enrique Gaztañaga †  Marc Manera  Tuomas Multamäki 《Monthly notices of the Royal Astronomical Society》2006,365(1):171-177

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Tailored data compression using stream partitioning and prediction: application to Gaia     

Jordi Portell  Enrique García-Berro  Xavier Luri  Alberto G. Villafranca 《Experimental Astronomy》2006,21(3):125-149

Gaia is the most ambitious space astrometry mission currently envisaged and it will be a technological challenge in all its aspects. Here we describe a proposal for the data compression system of Gaia, specifically designed for this mission but based on concepts that can be applied to other missions and systems as well. Realistic simulations have been performed with our Telemetry CODEC software, which performs a stream partitioning and pre-compression to the science data. In this way, standard compressors such as bzip2 or szip boost their performance and decrease their processing requirements when applied to such pre-processed data. These simulations have shown that a lossless compression factor of 3 can be achieved, whereas standard compression systems were unable to reach a factor of 2.   相似文献   

THERMAP: a mid-infrared spectro-imager for space missions to small bodies in the inner solar system     

O. Groussin  J. Licandro  J. Helbert  J. L. Reynaud  P. Levacher  M. Reyes García-Talavera  V. Alí-Lagoa  P. E. Blanc  E. Brageot  B. Davidsson  M. Delbó  M. Deleuze  A. Delsanti  J. J. Diaz Garcia  K. Dohlen  D. Ferrand  S. F. Green  L. Jorda  E. Joven Álvarez  J. Knollenberg  E. Kührt  P. Lamy  E. Lellouch  J. Le Merrer  B. Marty  G. Mas  C. Rossin  B. Rozitis  J. Sunshine  P. Vernazza  S. Vives 《Experimental Astronomy》2016,41(1-2):95-115

We present THERMAP, a mid-infrared spectro-imager for space missions to small bodies in the inner solar system, developed in the framework of the MarcoPolo-R asteroid sample return mission. THERMAP is very well suited to characterize the surface thermal environment of a NEO and to map its surface composition. The instrument has two channels, one for imaging and one for spectroscopy: it is both a thermal camera with full 2D imaging capabilities and a slit spectrometer. THERMAP takes advantage of the recent technological developments of uncooled microbolometer arrays, sensitive in the mid-infrared spectral range. THERMAP can acquire thermal images (8–18 μm) of the surface and perform absolute temperature measurements with a precision better than 3.5 K above 200 K. THERMAP can acquire mid-infrared spectra (8–16 μm) of the surface with a spectral resolution Δλ of 0.3 μm. For surface temperatures above 350 K, spectra have a signal-to-noise ratio >60 in the spectral range 9–13 μm where most emission features occur.  相似文献   

From saturated to unsaturated conditions and vice versa     

Martí Lloret-Cabot  Simon J. Wheeler  Jubert A. Pineda  Enrique Romero  Daichao Sheng 《Acta Geotechnica》2018,13(1):15-37

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Rock-magnetic properties of topsoils and urban dust from Morelia (>800,000 inhabitants), Mexico: Implications for anthropogenic pollution monitoring in Mexico’s medium size cities     

Bertha Aguilar Reyes  Francisco Bautista  Avto Goguitchaichvili  Juan Julio Morales Contreras  Julie Battu  Patricia Quintana Owen  Claire Carvallo 《Geofísica Internacional》2013,52(2):121-133

In this work, we investigate the correlation between some magnetic parameters and the level of contamination by heavy metals in urban soils from Morelia city, western Mexico. The magnetic study was carried out on 98 urban soils samples belonging to distinct land uses. Most of analyzed samples contain ferrimagnetic minerals as the responsible for magnetization, most probably corresponding to the titanomagnetites/ titanomaghemites solid solutions. This is inferred from the susceptibility vs. temperature measurements and the isothermal remanent magnetization (IRM) experiments. These measurements also indicate that most of samples are almost completely saturated before 300 mT. Additionally, the S_-200 values (S_-200 = IRM_-200/ SIRM, where IRM_-200= Back-field of 200 mT after magnetic saturation) are between 0.7 and 1.0, characteristic of low coercivity magnetic minerals. The averaged saturation isothermal remanent magnetization (SIRM) curves can be used as an indicator of pollution level, as these curves show different saturation values according to the level of contamination by heavy metals: Cu, Ni, Cr and Sr. These associations of (titano)magnetite with heavy metals were observed by Scanning Electron Microscope revealing some complex aggregates rather than commonly detected spherules.  相似文献   

Archeointensity investigation on pottery vestiges from Puertas de Rolón, Capacha culture: In search for affinity with other Mesoamerican pre-Hispanic cultures     

Juan Morales  Avto Goguitchaichvili  María de los Ángeles Olay Barrientos  Claire Carvallo  Bertha Aguilar Reyes 《Studia Geophysica et Geodaetica》2013,57(4):605-626

We report the results of a rock magnetic and archeointensity study on pottery fragments recovered at the archaeological site of Puertas de Rolón, Capacha culture (Colima), that is considered one of the most important pre-Classic cultural developments of western Mesoamerica, Mexico. Standard rock magnetic experiments were carried out in order to investigate the reliability of the ancient field strength recovered from studied materials. Six out of the seven analyzed fragments gave reliable intensity determinations. The mean archeointensity value obtained in this study is 35.3 ± 3.4 μT. It is in good agreement with another contemporaneous Mesoamerican mean archeointensity of 34.3 ± 1.1 μT obtained for El Opeño. Statistically similar rock-magnetic parameters between ceramics from El Opeño and Puertas de Rolón potsherds appear to be related to clay-sources with similar geological settings and weathering processes. Alternatively, ancient trade or interexchange between western (Capacha Culture) and eastern Mesoamerica locations, as it has been proposed earlier, seem to be supported by results obtained in this study.  相似文献