Land reclamation is gradually posing negative impact on man due to unplanned urbanization. A study was carried out on impact of land reclamation through sand mining of coastal communities in Ikate and Ilubirin in Lago...Land reclamation is gradually posing negative impact on man due to unplanned urbanization. A study was carried out on impact of land reclamation through sand mining of coastal communities in Ikate and Ilubirin in Lagos, Nigeria. Ten waters (8 surface and 2 groundwater sources), 10 soil samples and air were collected and taken for analysis. Results of water revealed concentrations lower than WHO (2017) and SON (2007) standards. Soil/sediment with average crustal value revealed Pb and Cd above standard values, which is attributed to anthropogenic influence on soils. Quality of air in the study was mainly particulate matter arising from the sea and reclaimed land in the surroundings of the environment with the highest Total Suspended Particulate of 0.8 mg/m3 in sulfur dioxide. This explains corrosion found on the roofs of the communities. Therefore, in the development planning adequate precautions should be put in place to avert environmental degradation.展开更多
It has been reported([1]) that when a loosely packed column of saturated sand in a vertical cylindrical container is shock loaded axially by dropping to the floor, large horizontal cracks initiate, grow and eventually...It has been reported([1]) that when a loosely packed column of saturated sand in a vertical cylindrical container is shock loaded axially by dropping to the floor, large horizontal cracks initiate, grow and eventually fade away in the sand as it settles under gravity. This paper shows that a similar phenomenon can also be observed when shock loading is replaced by forcing water to percolate upward through the sand column. It is believed that our result sheds further light on the physics of formation of these cracks.展开更多
Applying the air impact molding method to mold the complicated pattern with wider opening surface and deeper concave, there always exist vaulted phenomenon and lower compactibility of sand mold over the entrance and t...Applying the air impact molding method to mold the complicated pattern with wider opening surface and deeper concave, there always exist vaulted phenomenon and lower compactibility of sand mold over the entrance and the concave regions. Using the air-stream and synchro-formed clamp plate impact molding, however, this problem will be preferably solved. In this paper, the compact mechanism of the new molding method and the effect of some configuration factors, such as the area flowed by compressed air and the highness of the protruding block displacement around the diffluent clamp plate, on the compactibility of sand mold were discussed.展开更多
文摘Land reclamation is gradually posing negative impact on man due to unplanned urbanization. A study was carried out on impact of land reclamation through sand mining of coastal communities in Ikate and Ilubirin in Lagos, Nigeria. Ten waters (8 surface and 2 groundwater sources), 10 soil samples and air were collected and taken for analysis. Results of water revealed concentrations lower than WHO (2017) and SON (2007) standards. Soil/sediment with average crustal value revealed Pb and Cd above standard values, which is attributed to anthropogenic influence on soils. Quality of air in the study was mainly particulate matter arising from the sea and reclaimed land in the surroundings of the environment with the highest Total Suspended Particulate of 0.8 mg/m3 in sulfur dioxide. This explains corrosion found on the roofs of the communities. Therefore, in the development planning adequate precautions should be put in place to avert environmental degradation.
基金The project supported by the National Natural Science Foundation of China(19832010)by the Chinese Academy of Sciences(KJ952-S1-202)
文摘It has been reported([1]) that when a loosely packed column of saturated sand in a vertical cylindrical container is shock loaded axially by dropping to the floor, large horizontal cracks initiate, grow and eventually fade away in the sand as it settles under gravity. This paper shows that a similar phenomenon can also be observed when shock loading is replaced by forcing water to percolate upward through the sand column. It is believed that our result sheds further light on the physics of formation of these cracks.
文摘Applying the air impact molding method to mold the complicated pattern with wider opening surface and deeper concave, there always exist vaulted phenomenon and lower compactibility of sand mold over the entrance and the concave regions. Using the air-stream and synchro-formed clamp plate impact molding, however, this problem will be preferably solved. In this paper, the compact mechanism of the new molding method and the effect of some configuration factors, such as the area flowed by compressed air and the highness of the protruding block displacement around the diffluent clamp plate, on the compactibility of sand mold were discussed.
