نتایج جستجو برای: salt weathering
تعداد نتایج: 85804 فیلتر نتایج به سال:
This study investigated weathering performance of an HDPE wood plastic composite reinforced with extracted or delignified wood flour (WF). The wood flour was pre-extracted with three different solvents, toluene/ethanol (TE), acetone/water (AW), and hot water (HW), or sodium chlorite/acetic acid. The spectral properties of the composites before and after artificial weathering under accelerated c...
Acid weathering of plagioclase–pyroxene mixtures has been investigated with an open system kinetic dissolution model. The modeling reveals that elevated plagioclase/pyroxene ratios observed in some low-albedo martian regions and atmospheric dust could be partially caused by preferential dissolution of pyroxenes at pHs below ∼3–4. Surface materials with smaller grain sizes, affected by lower pH ...
The influence of accelerated weathering, xenon-arc light and freeze-thaw cycling on wood plastic composites extruded from a recycled plastic was studied. The results showed that, in general, weathering had a stronger impact on samples made from plastic waste compared to a sample made from virgin material. After weathering, the mechanical properties, tensile and flexural, were reduced by 2-30%, ...
Constraints on continental crustal mass loss via chemical weathering using lithium and its isotopes.
Chemical weathering, as well as physical erosion, changes the composition and shapes the surface of the continental crust. However, the amount of continental material that has been lost over Earth's history due to chemical weathering is poorly constrained. Using a mass balance model for lithium inputs and outputs from the continental crust, we find that the mass of continental crust that has be...
Hafnium 176Hf/177Hf isotope ratio variations in marine records are thought to reflect changes in continental weathering through time, but the behavior of Hf in rivers, and during weathering, is not well understood. Here, we present 176Hf/177Hf data for rivers, bedrock, soils, and leaching experiments for the Moselle basin, Vosges, France. These data strongly suggest that the 176Hf/177Hf composi...
-Chloritic veins in serpentinite and their weathering products were analyzed by X-ray powder diffraction (XRD) and X-ray fluorescence spectrometry (XRF). Chlorite formed during the Hercynianage orogenesis had apparently been partly transformed to high-charge vermiculite during subsequent metamorphism of the rocks. The idealized structural formulae for these minerals are (mlL9Fea+0.zFe2+o.4Mg9.2...
Mitochondrial DNA analysis of skeletal material is invaluable in forensic identification, although results can vary widely among remains. Previous studies have included bones of different ages, burial conditions, and even species. In the research presented, a collection of human remains that lacked major confounders such as burial age, interment style, and gross environmental conditions, while ...
Over millions of years, the oxidation of organic carbon contained within sedimentary rocks is one of the main sources of carbon dioxide to the atmosphere, yet the controls on this emission remain poorly constrained. We use rhenium to track the oxidation of rock-bound organic carbon in the mountain watersheds of New Zealand, where high rates of physical erosion expose rocks to chemical weatherin...
In situ quantification of localizedweathering processes on basalt flows inNewMexico andHawaii demonstrates that small-area factors can be more important than other more readily observable factors. Further, it demonstrates that the factorial concept of the Pope Boundary-Layer weathering model is partially solvable, that organicweathering can accentuate glassweathering (with implications for clim...
It has been proposed that increased rates of chemical weathering and the related drawdown of atmospheric CO on the 2 Ž . continents may have at least partly contributed to the low CO concentrations during the last glacial maximum LGM . 2 Variations in continental erosion could thus be one of the driving forces for the glacialrinterglacial climate cycles during Quaternary times. To test such an ...
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