نتایج جستجو برای: weathering resistance

تعداد نتایج: 381072  

Journal: Geopersia 2018

In this study, the salt weathering effects on engineering properties and weight loss potential of three types of granitoid rocks were investigated. Sodium and magnesium sulfates tests were performed on core and aggregate samples. The cyclic salt weathering tests on core samples were done up to 90 cycles, while these tests on aggregate samples were done up to 40 cycles. The results showed that d...

2013
Guang-Hui Zhu Xiao-Jun Yu Liang-Xing Xie Hao Luo Dian Wang Jun-Yao Lv Xiao-Hu Xu

Determination of the postmortem interval (PMI) is crucial for investigating homicide. However, there are currently only limited methods available. Especially, once the PMI exceeds the duration of pre-adult development of the flies with the adult emergence, its determination is very approximate. Herein, we report the regular changes in hydrocarbon composition during the weathering process of the...

2008
Pak Kin Wong Fuqu Yu Arash Shahangian Genhong Cheng Ren Sun Ming Ho

Continental crust rises higher than oceanic crust because it is less dense: It is rich in Si and poor in Mg. However, basalt, which is derived from magma, is denser and has a higher ratio of Mg to Si than the rock that makes up mature continental crust. Cin-Ty Lee et al. argue that chemical weathering alters the composition of continental crust as it ages and helps give it its more buoyant char...

2015
Talitha C. Santini Martin V. Fey Robert J. Gilkes Suresh Bhargava

Bauxite residue is an alkaline, saline tailings material generated as a byproduct of the Bayer process used for alumina refining. Developing effective plans for the long term management of potential environmental impacts associated with storage of these tailings is dependent on understanding how the chemical and mineralogical properties of the tailings will change during weathering and transfor...

2015
Jingheng Guo Fushun Wang Rolf David Vogt Yuhang Zhang Cong-Qiang Liu

Chemical weathering is a fundamental geochemical process regulating the atmosphere-land-ocean fluxes and earth's climate. It is under natural conditions driven primarily by weak carbonic acid that originates from atmosphere CO2 or soil respiration. Chemical weathering is therefore assumed as positively coupled with its CO2 consumption in contemporary geochemistry. Strong acids (i.e. sulfuric- a...

2017
Nick F Pidgeon Elspeth Spence

This paper addresses the social acceptability of enhanced weathering, a technology that would involve spreading silicate particles over terrestrial surfaces in order to boost the biological processes that currently sequester CO2 as part of the earth's natural carbon cycle. We present the first exploration of British attitudes towards enhanced weathering, using an online survey (n = 935) of a re...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2012
Lyla L Taylor Steve A Banwart Paul J Valdes Jonathan R Leake David J Beerling

Global weathering of calcium and magnesium silicate rocks provides the long-term sink for atmospheric carbon dioxide (CO(2)) on a timescale of millions of years by causing precipitation of calcium carbonates on the seafloor. Catchment-scale field studies consistently indicate that vegetation increases silicate rock weathering, but incorporating the effects of trees and fungal symbionts into geo...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Cin-Ty Aeolus Lee Douglas M Morton Mark G Little Ronald Kistler Ulyana N Horodyskyj William P Leeman Arnaud Agranier

Continents ride high above the ocean floor because they are underlain by thick, low-density, Si-rich, and Mg-poor crust. However, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during their maturation into continents. Igneous differentiation followed by lower crustal delamination and chemical weathering followed by subduction recycling are pos...

2008
Wei Luo Alan D. Howard

6 [1] The role of groundwater in forming Martian valley networks is simulated in a 7 computer model as seepage erosion by contributing to surface runoff and as seepage 8 weathering by causing accelerated weathering of bedrock, which makes its subsequent 9 erosion and removal easier. Simulation results show that seepage erosion cannot mobilize 10 large grain size sediment and is marginally effec...

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