نتایج جستجو برای: geochemical evaluation

تعداد نتایج: 836003  

Journal: :Journal of contaminant hydrology 2001
N Sun M Elimelech N Z Sun J N Ryan

A two-dimensional model for colloid transport in geochemically and physically heterogeneous porous media is presented. The model considers patchwise geochemical heterogeneity, which is suitable to describe the chemical variability of many surficial aquifers with ferric oxyhydroxide-coated porous matrix, as well as spatial variability of hydraulic conductivity, which results in heterogeneous flo...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Steffen Leth Jorgensen Bjarte Hannisdal Anders Lanzén Tamara Baumberger Kristin Flesland Rita Fonseca Lise Ovreås Ida H Steen Ingunn H Thorseth Rolf B Pedersen Christa Schleper

Microbial communities and their associated metabolic activity in marine sediments have a profound impact on global biogeochemical cycles. Their composition and structure are attributed to geochemical and physical factors, but finding direct correlations has remained a challenge. Here we show a significant statistical relationship between variation in geochemical composition and prokaryotic comm...

Journal: :journal of mining and environment 2015
h. shahi r. ghavami riabi a. kamkar ruhani h. asadi haroni

in this research work, the frequency domain (fd) of surface geochemical data was analyzed to decompose the complex geochemical patterns related to different depths of the mineral deposit. in order to predict the variation in mineralization in the depth and identify the deep geochemical anomalies and blind mineralization using the surface geochemical data for the dalli cu-au porphyry deposit, a ...

Abstract Most conventional statistical methods aiming at defining geochemical concentration thresholds for separating anomalies from background have limited effectiveness in areas with complex geological settings and variable lithology. In this paper, median+2MAD as a method of exploratory data analysis (EDA) and concentration-area (C-A) fractal model as two effective approaches in separation g...

2002
A. S. Barabash

A comparison is made of the probability of the process of two neutrino double beta decay for Se in direct (counter) and geochemical experiments. It is shown that the probability is systematically lower in geochemical experiments, which characterize the probability of ββ(2ν) decay a few billions years ago. The experimental data for Te are also analyzed. It is shown that geochemical measurements ...

Journal: :Communications, Faculty of Science, University of Ankara Series C Biology, Geological Engineering and Geophysical Engineering 1987

2005
Katrin Grünfeld

Geochemical mapping programs carried out by the Geological Survey of Sweden (SGU) have generated large databases containing information on the concentrations of chemical elements in rocks, surface sediments and biogeochemical materials. Regional geochemical data being imprecise, multivariate, spatially auto-correlated and non-normally distributed pose specific problems to the choice of data ana...

Journal: :Environmental pollution 2006
G B Pasternack K J Brown

The geochemical history of an upper deltaic plain pending tidal wetland restoration was reconstructed to assess remobilization of redox-sensitive constituents in sediment, identify depositional processes promoting geochemical retention, and determine the extent of contamination with Hg, As, Pb, Cu, and Zn. Three 12-14-m sediment cores were analyzed for bulk sediment geochemistry using ICP-AES. ...

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