نتایج جستجو برای: clay minerals

تعداد نتایج: 41990  

2014
Sohan Jheeta Prakash C. Joshi

This review summarizes our recent findings on the role of mineral salts in prebiotic RNA synthesis, which is catalyzed by montmorillonite clay minerals. The clay minerals not only catalyze the synthesis of RNA but also facilitate homochiral selection. Preliminary data of these findings have been presented at the "Horizontal Gene Transfer and the Last Universal Common Ancestor (LUCA)" conference...

2014
Francis Moyo Roman Tandlich Brendan S. Wilhelmi Stefan Balaz

Renewed focus on the sorption of hydrophobic organic chemicals (HOCs) onto mineral surfaces and soil components is required due to the increased and wider range of organic pollutants being released into the environment. This mini-review examines the possibility of the contribution and mechanism of HOC sorption onto clay mineral sorbents such as kaolinite, and soil organic matter and the possibl...

2012
Navjeet Kaur Dharma Kishore

Reactions of organic molecules on Montmorillonite clay mineral have been investigated from various aspects. These include catalytic reactions for organic synthesis, chemical evolution, the mechanism of humus-formation, and environmental problems. Catalysis by clay minerals has attracted much interest recently, and many reports including the catalysis by synthetic or modified clays have been pub...

2000
Yoko Furukawa

High resolution (<10 nm) transmission electron microscopy (TEM), energy-®ltering TEM (EFTEM), and electron energy loss spectroscopy (EELS) have been used for the direct microstructural imaging and analysis of clay-organic matter aggregates in ®ne-grained aquatic sediments from Jourdan River Estuary, MS, USA. EFTEM and EELS allow rapid, high-resolution spatial mapping and analysis of light eleme...

Journal: :Applied microbiology 1972
G Bitton Y Henis N Lahav

The effect of various clay minerals and humic acid on the survival of Klebsiella aerogenes exposed to ultraviolet (UV) irradiation was investigated. A protective effect was observed and found to depend on the specific light absorption and light scattering properties of the clay minerals and the humic acid used. The higher the specific absorption, the better was the survival of K. aerogenes afte...

2002
ZHANG Weiguo

Magnetic, granulometric and geochemical analyses were conducted on an intertidal sediment core from the Yangtze Estuary to evaluate the possibility of normalizing samples for particle size effects in a heavy metal pollution study by means of magnetic proxies. It has been found that the magnetic parameter χARM, indicating fine grained ferrimagnetic minerals, correlates well with the clay content...

2007
Tony Christie Bruce Thompson

Clay, as a rock term, describes a soft, loose, earthy material containing particles with an average grain size of less than than 0.004 mm (4 mm) in the Wentworth grain size scale and less than 0.002 mm (2 mm) in most soil investigations. Clay is composed mostly of clay minerals, but may also contain quartz, feldspar, carbonates, ferruginous material, and other non-clay materials. All clays, apa...

2015
Andrea K. Weber James M. Russell Timothy A. Goudge Mark R. Salvatore John F. Mustard Satria Bijaksana

We tested the use of visible to near-infrared (VNIR) reflectance spectroscopy to characterize the relative abundances of clay minerals in sediments from Lake Towuti, a large tectonic lake in Sulawesi, Indonesia. We measured VNIR spectra of lake and river sediments from Lake Towuti and its catchment to identify clay minerals, fit major VNIR absorption features with a modified Gaussian model to e...

2006
A. TSUNASHIMA F. KANAMARU S. UEDA

-An attempt has been made to synthesize nitrogenous clay minerals hydrothermally from silicaalumina gels in the presence of amino acids, namely glycine and lysine, The products have been characterized by X-ray powder diffraction, by analyses for C and N contents, and by their infrared spectra. Amino acid-montmorillonites have been prepared under hydrothermal conditions of 200-250~ and 1000 atm....

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