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1. chinaXiv:201903.00239 [pdf]

An experimental study on the influences of water erosion on wind erosion in arid and semi-arid regions

YANG Huimin
Subjects: Geosciences >> Geography

Complex erosion by wind and water causes serious harm in arid and semi-arid regions. The interaction mechanisms between water erosion and wind erosion is the key to further our understanding of the complex erosion. Therefore, in-depth understandings of the influences of water erosion on wind erosion is needed. This research used a wind tunnel and two rainfall simulators to investigate the influences of water erosion on succeeding wind erosion. The wind erosion measurements before and after water erosion were run on semi-fixed aeolian sandy soil configured with three slopes (5°, 10° and 15°), six wind speeds (0, 9, 11, 13, 15 and 20 m/s), and five rainfall intensities (0, 30, 45, 60 and 75 mm/h). Results showed that water erosion generally restrained the succeeding wind erosion. At a same slope, the restraining effects decreased as rainfall intensity increased, which decreased from 70.63% to 50.20% with rainfall intensity increased from 30 to 75 mm/h. Rills shaped by water erosion could weaken the restraining effects at wind speed exceeding 15 m/s mainly by cutting through the fine grain layer, exposing the sand layer prone to wind erosion to airflow. In addition, the restraining effects varied greatly among different soil types. The restraining effects of rainfall on the succeeding wind erosion depend on the formation of a coarsening layer with a crust and a compact fine grain layer after rainfall. The findings can deepen the understanding of the complex erosion and provide scientific basis for regional soil and water conservation in arid and semi-arid regions.

submitted time 2019-03-28 From cooperative journals:《Journal of Arid Land》 Hits13037Downloads1990 Comment 0

2. chinaXiv:201712.00400 [pdf]

A field investigation of wind erosion in the farming–pastoral ecotone of northern China using a portable wind tunnel: a case study in Yanchi County

NAN, Ling; DONG, Zhibao; XIAO, Weiqiang; LI, Chao; XIAO, Nan; SONG, Shaopeng; XIAO, Fengjun; DU, Lingtong
Subjects: Geosciences >> Other Disciplines of Geosciences

The farming–pastoral ecotone in northern China is an extremely fragile ecological zone where wind erosion of cropland and rangeland is easy to occur. In this study, using a portable wind tunnel as a wind simulator, we conducted field simulated wind erosion experiments combined with laboratory analysis to investigate wind erosion of soils in trampled rangeland, non-tilled cropland and tilled cropland in Yanchi County, China. The results showed that compared with rangeland, the cropland had a higher soil water holding capacity and lower soil bulk density. The wind erosion rate of trampled rangeland was much higher than those of non-tilled cropland and tilled cropland. For cropland, the wind erosion rate of the soil after tilling was surprisingly less than that of the soil before tilling. With increasing of wind speed, the volume mean diameter of the eroded sediment collected by the trough in the wind tunnel generally increased while the clay and silt content decreased for all soils. The temporal variation in wind erosion of the trampled rangeland indicated that particle entrainment and dust emission decreased exponentially with erosion time through the successive wind erosion events due to the exhaustion of erodible particles.

submitted time 2017-12-08 From cooperative journals:《Journal of Arid Land》 Hits1951Downloads599 Comment 0

3. chinaXiv:201705.00571 [pdf]

Dispersion characterisation of CaCO3 particles in PP/CaCO3 composites

Zhu, YD [Zhu, Y. D.][ 1,2 ]; Allen, GC [Allen, G. C.][ 2 ]; Jones, PG [Jones, P. G.][ 3 ]; Adams, JM [Adams, J. M.][ 4 ]; Gittins, DI [Gittins, D. I.][ 3 ]; Heard, PJ [Heard, P. J.][ 2 ]; Skuse, DR [Skuse, D. R.][ 3 ]
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Polypropylene and calcium carbonate were prepared by melt extrusion in a twin screw extruder or cast- ing in a kneader extruder. The dispersion of CaCO3 particles in PP was analysed through the observation of impact-fracture surface, polished surface, cross-section surface and film using scanning electron microscopy (SEM), focused ion beam (FIB) and optical transmission microscopy (OTM). Only basic infor- mation on particle dispersion was obtained from the investigation of fracture surfaces by SEM and the FIB cross-sections by virtue of the ambiguous phase contrast and the limited area observed. However, the SEM images from polished-surfaces and the film images observed in OTM show the different particle dispersion in different samples. The derived Particle Size Distribution (PSD) curves from OTM images explain the difference of impact strength, demonstrating the relationship between particle dispersion and mechanical properties.

submitted time 2017-05-02 Hits1940Downloads294 Comment 0

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