نتایج جستجو برای: mechanical weathering

تعداد نتایج: 242214  

2011
Xiaolong Li Duoxi Yao Jinxiang Yang

Lithological characteristics, mineral composition, physical properties of water and physical and mechanical properties, weathering zone distribution and other factors of bedrock weathering zone in coal-seam roof determine the strength of its watertight performance, while its performance has a direct impact on impermeable overlying loose surface water aquifers as well as the possible collapse in...

Journal: :Journal of Constructional Steel Research 2020

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی 1391

in this study, the effects of oleothermal modification on physical and mechanical peroperties of fir wood (abeis sp.) blocks were examined. at first, some blocks of fir wood with 5 × 20 × 120 cm dimensions were prepared. the blocks were treated in soybean oil. the effects of 3 factors such as treatments temperature (180and 200 °c), holding time (12 and 15 h) and initial moisture content of wood...

2000
Jie Chen Hans-Peter Blume Lothar Beyer

The evidence presented by numerous investigations of the interface between lichens and their rock substrates strongly suggests that the weathering of minerals can be accelerated by the growth of at least some lichen species. The effects of lichens on their mineral substrates can be attributed to both physical and chemical processes. The physical effects are reflected by the mechanical disruptio...

Journal: :Journal of Mining and Metallurgy, Section B: Metallurgy 2015

A. Jamshidi A. Zalooli H. Yeganehfar M. Khamehchiyan M.R. Nikudel

     Salt crystallization is one of the most powerful weathering agents that may cause a rapid change in the mechanical properties of stones, and thus limit their durability. Consequently, determining the mechanical properties of stones due to salt crystallization is important for natural building stones used in marine environmental and mild climatic conditions, which expose excessive salt crys...

Journal: :Journal of Geophysical Research: Earth Surface 2016

2006
Jason R. Price Michael A. Velbel

Chemical weathering indices are commonly used for characterizing weathering profiles by incorporating bulk major element oxide chemishy inlo a single metric for each sample. Generally, on homogeneous parent rocks, weathering indices change systematically with depth. However, the weathering of heterogeneous metamorphic rocks confounds the relationship between weathering index and depth. In this ...

2017
Nicolas Kalogerakis Katerina Karkanorachaki G. Calypso Kalogerakis Elisavet I. Triantafyllidi Alexandros D. Gotsis Panagiotis Partsinevelos Fabio Fava

The fragmentation of high-density polyethylene (HDPE) films from single-use supermarket plastic bags to microplastics under laboratory-simulated onshore and nearshore conditions was investigated for a period of 6 months. The weathering process of the plastic strips either on beach sand or in seawater under direct natural sunlight was monitored by tensile strength, molecular weight measurements,...

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