نتایج جستجو برای: weathering pattern
تعداد نتایج: 354090 فیلتر نتایج به سال:
In order to analyze and study the composition of ancient glass products, this paper preprocessed data carried out statistical analysis charts qualitatively relationship between weathering color, type pattern cultural relics, established a Logistic regression model for quantitative analysis. There are four types relics according whether they weathered. Through evaluation principal component anal...
Despite evidence that weathering plays a role in forming intertidal, estuarine, and fluvial rock platforms, many publications uncritically refer to “wave-cut” or “stream-cut” rock platforms. The alternative explanations of chemical weathering and physical water erosion of rock platforms have been debated since 1839. Our new approach to this long-standing problem introduces data from fluvial as ...
Papers published in Hydrology and Earth System Sciences Discussions are under open-access review for the journal Hydrology and Earth System Sciences Abstract Major environmental stressors of boreal and sub-arctic rivers are hydrological changes and global warming and both factors will significantly influence the future evolution of the river chemistry in high latitudes. We tested the hypothesis...
Heavy metals are of wide concern due to their high toxicity, bioaccumulation and non-degradability. In this study, eight heavy (Cr, Mn, Ni, Cu, Zn, As, Cd, Pb) in the surface sediments Ningyuan River were studied investigate distribution pattern, pollution status potential sources, it was concluded that concentration is highly consistent with population pattern space there a certain degree risk...
The halogen concentrations of a number of Martian meteorites vary significantly, with larger variations observed in I/Cl compared to Br/Cl. One striking feature is the high I/Cl ratios associated with those meteorites found in Antarctica. Removal of low temperature, superficial contamination does not significantly reduce the I/Cl ratio [1], indicating that processing in Antarctica is responsibl...
Common naturally occurring orthosilicates can be grouped into those in which the major non-tetrahedral cations are (1) FeII and/or Mg, plus or minus Al (olivine, pyralspite garnets, staurolite); (2) Al (Al2SiO5 polymorphs), or (3) Zr. Feand Mg-bearing orthosilicates have the weakest bonds between non-tetrahedral cations and structural oxygen (M-O bonds), and zircon the strongest, with Al-O bond...
Chemical weathering rates and erosion rates of granitic till in northern Sweden have been estimated. The present-day chemical weathering rate is compared with the long-term average weathering rate since the last deglaciation approximately 8,700 years ago. Also, the present-day release rates of major and trace elements due to chemical weathering are compared with the mobility of these elements i...
Space weathering causes the change in optical properties, such as darkening, reddening, and decrease of absorption depths of the planetary surfaces. Two competing processes have been proposed so far as the main mechanism of such space weathering; hydrogen irradiation by solar wind and bombardment of micrometeorites. We use the new data set obtained by Spectral Profiler (SP) onboard SELENE/Kaguy...
Bauxite deposit of Permo-Triassic age in northeast of Bukan was developed stratiformly along the boundary between Ruteh and Elika formations, and includes four distinct rock units. This deposit was affected by tectonic and morphological processes. Mineralogical and geochemical investigations showed that during weathering processes, two mechanisms of ferrugenization and deferrugenization played ...
STATEMENT OF PROBLEM Maxillofacial prostheses are serviceable for approximately 6 months, after which they need to be refabricated because of the deterioration of color and physical properties. PURPOSE This third article in a 3-part series evaluated the color stability of commonly used colorant-elastomer combinations as a result of exposure to weathering. METHODS AND MATERIAL Fifteen specim...
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