نتایج جستجو برای: minerals composition
تعداد نتایج: 278641 فیلتر نتایج به سال:
In several articles on trace elements in mushrooms erroneous data were published on minerals sequestered in fruiting bodies. The biased analytical data published gave a false picture on the composition and nutritional value of mushrooms with respect to minerals. Wild mushrooms are relatively rich in trace elements and some species can hyperaccumulate certain metals. Selenium as reported in the ...
The prebiotic significance of laboratory experiments that study the interactions between oligomeric RNA and mineral species is difficult to know. Natural exemplars of specific minerals can differ widely depending on their provenance. While laboratory-generated samples of synthetic minerals can have controlled compositions, they are often viewed as "unnatural". Here, we show how trends in the in...
More than half of the >5000 approved mineral species are known from five or fewer localities and thus are rare. Mineralogical rarity arises from different circumstances, but all rare mineral species conform to one or more of four criteria: (1) P-T-X range: minerals that form only under highly restricted conditions in pressure-temperature-composition space; (2) Planetary constraints: minerals th...
i FOREWORD iii ACKNOWLEDGMENTS v SYMBOLS ix 1 THERMODYNAMIC RELATIONS IN CRYSTALLINE SOLUTIONS 1 2 THERMODYNAMIC STABILITY OF A SOLUTION 11 3 COMPOSITION OF COEXISTING PHASES 15 4 MEASUREMENT OF COMPONENT ACTIVITIES BY ANALYSIS OF PHASE DIAGRAMS 25 5 MEASUREMENT OF COMPONENT ACTIVITY USING COMPOSITION OF COEXISTING MINERALS 35 6 ORDER-DISORDER IN Fe-Mg SILICATES 39
Mantle-derived xenoliths brought to the Earth’s Surface by basalts are important windows to understand composition, evolution and processes of the lithospheric mantle. The lithosphere of the southeastern China is dominated by peridotite or lherzolite [1, 2]. The spinel peridotite xenoliths studied are from Fangshan basalt, eastern China, which are composed of olivine, clinopyroxene, orthopyroxe...
Plants provide an important source of minerals for human and animal consumption. There is a general worldwide deficiency of human intake of several essential minerals, including iron, zinc, copper, calcium, magnesium, selenium, and iodine (White & Broadley, 2009). This deficiency exists not only in developing countries, but also in the developed world. On the other hand, excessive amounts of he...
Two experiments were conducted to determine the digestible energy (DE) and metabolizable energy (ME) content of 19 rice bran samples and to develop prediction equations for DE and ME based on their chemical composition. The 19 rice bran samples came from different rice varieties, processing methods and regions. The basal diet was formulated using corn and soybean meal (74.43% corn and 22.91% so...
A b s t r a c t The variation of silicate dissolution and crystallization rates with chemical affinity and solution composition can be quantified by the identification of the rate controlling precursor complex. The nature of this complex depends on the individual mineral structure. Specifically, the destruction of quartz and anorthite frameworks requires the breaking of only one type of structu...
The Mars Science Laboratory landed in Gale crater on Mars in August 2012, and the Curiosity rover then began field studies on its drive toward Mount Sharp, a central peak made of ancient sediments. CheMin is one of ten instruments on or inside the rover, all designed to provide detailed information on the rocks, soils and atmosphere in this region. CheMin is a miniaturized X-ray diffraction/X-r...
We present a comprehensive analysis of spatially resolved moderate spectral resolution near-infrared spectra obtained with the adaptive optics system at the Keck Observatory. We identify three compositionally distinct end member regions: the trailing hemisphere bullseye, the leading hemisphere upper latitudes, and a third component associated with leading hemisphere chaos units. We interpret th...
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