The Influence of Surface Stress Fluctuation on Saltation Sand Transport Around Threshold

2020 ◽  
Vol 125 (5) ◽  
Author(s):  
Xiaojing Zheng ◽  
Ting Jin ◽  
Ping Wang
1980 ◽  
Vol 1 (17) ◽  
pp. 93 ◽  
Author(s):  
John R. Hails ◽  
John Bennett

Little is known about how air-sediment interaction processes control the differential rates and direction of dune migration along the coast of South Australia. Information is needed on sand transport and dune formation in order to establish better guidelines for conservation and agricultural management programmes in areas that are undergoing erosion. The writers, with financial support from the Coast Protection Board, Department for the Environment, South Australia, have commenced a pilot research project to examine dunes in the lower Coorong and adjacent areas in the southeast of the State (Figure 1). The aims of the project are - To determine: (a) instantaneous surface stress values on the windward slopes of active transgressive dunes; (b) sand movement over the crestline as a function of surface stress on the windward slope in order to establish the life expectancy of stability of individual dunes; (c) the extent to which the local topography affects the wind regime in the dunal areas. To obtain: (a) air trajectories over and around transgressive dunes; (b) information on dune geometry (slope inclinations, crest heights, base lengths, etc.).


2020 ◽  
Vol 22 (4) ◽  
pp. 939-958
Author(s):  
Indrajit Roy ◽  
D. P. Acharya ◽  
Sourav Acharya

AbstractThe present paper investigates the propagation of quasi longitudinal (qLD) and quasi transverse (qTD) waves in a magneto elastic fibre-reinforced rotating semi-infinite medium. Reflections of waves from the flat boundary with surface stress have been studied in details. The governing equations have been used to obtain the polynomial characteristic equation from which qLD and qTD wave velocities are found. It is observed that both the wave velocities depend upon the incident angle. After imposing the appropriate boundary conditions including surface stress the resultant amplitude ratios for the total displacements have been obtained. Numerically simulated results have been depicted graphically by displaying two and three dimensional graphs to highlight the influence of magnetic field, rotation, surface stress and fibre-reinforcing nature of the material medium on the propagation and reflection of plane waves.


Author(s):  
Theresa Han ◽  
Eunin Cho ◽  
Jinwoo Heo ◽  
Seoung Jae Lee

Abstract In the manufacture of Printed Wiring Boards (PWB), unwelcome structures, such as nodules and whiskers can be formed during copper electroplating with copper sulfate. Copper (Cu) whiskers with lengths of up to a few hundred micrometers can lead to electrical shorts between layers or patterns. In this paper, we document factors that can affect the growth of Cu whiskers; decomposition of additives in the Cu electroplating solution, surface stress, acidic cleaner, and the ingredients of a dry film. Contaminants from outside of the electroplating bath and the ingredients of the dry film were shown as key components in the formation of Cu whiskers.


2020 ◽  
Vol 13 (11) ◽  
pp. 115004
Author(s):  
Yehejong Saqier ◽  
Guohong Yun ◽  
Bai Narsu

Author(s):  
Ryo Sakamoto ◽  
Ryo Sakamoto ◽  
Satoquo Seino ◽  
Satoquo Seino ◽  
Hirokazu Suzaki ◽  
...  

A construction of breakwaters and other shoreline structures on part of a coast influences drift sand transport in the bay, and causes comprehensive topographic changes on the beach. This study investigated shoreline and coastal changes, taking as an example of Shiraragahama Beach in Miiraku on the northwestern end of Fukue Island, Nagasaki Prefecture (Kyushu, Japan). Miiraku, adjacent to Saikai National Park, appears in the revered 8th century poetry collection “Manyoshu” and served as a port for a ship taken by the Japanese envoy to China during the Tang Dynasty (618-709). Because of the recent development of breakwaters for a fishing harbor, the shore environments of this beach have changed significantly. In this study, the status of silt deposits and topographic changes on this beach arising from the construction of a harbor breakwater were evaluated by comparing aerial photographs taken in different years. Next, the changes in the shoreline visible from aerial photographs from 1947 to 2014 were analyzed. Lastly, the altitude of the beaches was measured using accurate survey methods. The following results were obtained: 1) coastal erosion made rock cliffs to fall off along the shore and deposited sand on this beach; 2) the more serious advances or retreats of the shoreline took place around shoreline structures; 3) sandbars and beach cliffs were formed.


Author(s):  
Toshinori ISHIKAWA ◽  
Takaaki UDA ◽  
Masumi SERIZAWA ◽  
Shiho MIYAHARA ◽  
Ryo MOROHASHI ◽  
...  
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