Buildings and civil engineering works-Sealants-Determination of changes in cohesion and appearance of elastic weatherproofing sealants after exposure of statically cured specimens to artificial weathering and mechanical cycling

Foreword ISO(the International Organization for Standardization)is a worldwide federation of national standards bodies(ISO member bodies).The work of preparing International Standards is normally carried out through ISO technical committees.Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.

Geochemical characteristics and growth suitability assessment of Scutellaria baicalensis Georgi in the Earth's critical zone of North China

Geochemical differentiation of soils has a series of consequences on plant and places pressure on the ecological environment.The quantitative evaluation of element migration in the Earth’s critical zone is a challenging task.In this study,two demonstration study areas of Scutellaria baicalensis Georgi were selected,and multiple chemical weathering indexes,chemical loss fraction,mass migration coefficients and biological enrichment coefficient method were used to assess the ecological and geochemical suitability.The results show that for the element of Fe,Zn,Se,Cu,Co,Ni,Mo and Ge,the degree of weathering and soil maturation,were greater in the rhyolitic tuff area than in the Plagioclase gneiss area.In both research sites,the heavy metal level of samples in Scutellaria baicalensis Georgi did not exceed the standard limits.The plagioclase gneiss region’s surface soil environment was more alkaline,and the content of soil organic matter was lower,resulting in a higher bioenrichment intensity of Ge,Co,Cu,and Se elements in Scutellaria baicalensis Georgi than in the rhyolite-tuff area.The elements of Cd,Nb,Mo,Pb and As are considerably enriched in the soil of the plagioclase gneiss area but lost by leaching in the soil of the rhyolite tuff area,which is connected to the interplay of elemental abundance and human impact in the parent materials.This study provides a good example of how to assess growth suitability of Chinese medicinal materials in the Earth’s critical zone.

Effect of temperature on mudstone disintegration process revealed with image analysis

Quantifying rock weathering processes,especially in ways of nondisturbance and on-site investigation,is one of the most critical tasks in predicting rocks erosion rates and understanding the sediment transportation.We proposed a more reproducible approach to test how image analysis can quantify the changes in the size and shape of fragments during the weathering process.Four artificial models were designed to select suitable metrics among over 20 parameters.To validate the efficiency of image analysis,we analyzed rocks from badlands in Nanxiong Basin,Southeast China,under three different ranges of temperature differences(TD)during cyclic wetting and drying(WD).Our results show that TDs can accelerate the disintegration rate,and even if there is only a 20℃ difference in the range of TDs,an apparent difference in fragment size was observed.Moreover,the shape of fragments became more round as the increasing number of cyclic treatments,and for samples that went through the same number of treatments,the larger the temperature difference,the more round the shape became.All that serves as another evidence for landscape evolution response to climatic warming.