The South Yellow Sea(SYS) is strongly influenced by the substantial sediment loads of the Huanghe(Yellow)(including the modern Huanghe and abandoned old Huanghe subaqueous delta) and Changjiang(Yangtze) Rivers. Howeve...The South Yellow Sea(SYS) is strongly influenced by the substantial sediment loads of the Huanghe(Yellow)(including the modern Huanghe and abandoned old Huanghe subaqueous delta) and Changjiang(Yangtze) Rivers. However,the dispersal patterns of these sediments,especially in the western SYS,have not been clearly illustrated. In this study,we have analyzed clay minerals,detrital minerals,and grain sizes for 245 surface sediment samples(0–5 cm) collected from the western SYS. The clay minerals,on average,consist of 67% illite,14% smectite,11% chlorite,and 8% kaolinite. Clay minerals,detrital minerals,and grain size analyses of surface sediments,combined with water mass hydrology analysis,reveal that sediments in the western SYS are mainly derived from the modern Huanghe River,the abandoned subaqueous delta of the old Huanghe River,some material from the Changjiang,and coastal erosion. The clay minerals(especially illite and smectite) and quartz/feldspar ratio distribution patterns,reveal that the influence of modern Huanghe sediments can reach 35°N in the northwestern part of the study area,an influence that can be enhanced especially in winter owing to northerly winds. Conversely,sediments along the Jiangsu coast are mixed,in summer,with material from the Changjiang arriving via northward flow of Changjiang Diluted Water. The Subei Coastal Current carries the refreshed sediments northward into the western SYS. Sediment distribution and transport in the western SYS are mainly controlled by the oceanic circulation system that is primarily related to the monsoon.展开更多
The clay minerals of more than 200 soil samples collected from various sites of Fujian Province were studied by the X-ray diffraction method and transmission electron microscopy to study their distribution and evoluti...The clay minerals of more than 200 soil samples collected from various sites of Fujian Province were studied by the X-ray diffraction method and transmission electron microscopy to study their distribution and evolution. Montmorillonite was found in coastal solonchak, paddy soils derived from marine deposit, lacustrine deposit and river deposit, and some latentic red soil, red soil and yellow soil with a low weathering degree. Chlorite existed mainly in coastal solonchak and paddy soil developed from marine deposit. 1.4 nm intergradient mineral appeared frequently in yellow soil, red soil and latentic red soil. The content of l.4 nm intergradient mineral increased with the decrease of weathering degree from latentic red soil to red soil to yellow soil. Hydrous micas were more in coastal solonchak, paddy soils derived from marine deposit, lacustrine deposit and river deposit, and purple soil from purple shale than in other soils. Kaolinite was the most important clay mineral in the soils in this province. The higher the soil weathering degree, the more the kaolinite existed. From yellow soil to red soil to latentic red soil, kaolinite increased gradually. Kaolinite was the predominant clay mineral accompanied by few other minerals in typical latentic red soil. Tubular halloysite was a widespread clay mineral in soils of Fujian Province with varying quantities. The soil derived from the parent rocks rich in feldspar contained more tubular halloysite. Spheroidal halloysite was found in a red soil and a paddy soil developed from olivine basalt. Gibbsite in the soils in this district was largely 'primary gibbsite' which formed in the early weathering stage. Gibbsite decreased with the increase of weathering degree from yellow soil to red soil to latentic red soil. Goethite also decreased in the same sequence while hematite increased.展开更多
In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental co...In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental conditions. It is also important that the time required for transportation should be minimum. In this paper a method has been proposed for the minimization of transportation costs. Supply and transportation costs per unit of the quantities are also determined. The present study was carried out to evaluate the quality of gravel to know its suitability for aggregate (raw material for concrete and road). The samples of gravel were analyzed for petrographic, physical, mechanical and chemical properties. Samples were categorized as quartzite group and carbonate group according to ASTM standard 295. Among these, samples of quartzite group were found dominant. The petrography examination of gravels which was carried out constituted of opal, tridymite, chalcedony, crystobalite and alkali carbonates rocks. Those minerals react with alkalis in cement leading to expansion and cracking of concrete. Other components such as sulfides, sulfates, halites, iron oxides, clay minerals and anhydrites are examined, which might be present as coating and impurities. The present study indicated that all samples are suitable for concrete making and obtain the optimum solution for transporting these materials from quarries to cities with minimum cost according to Egyptian Code.展开更多
Up till now all the clay mineral studies on the soils of the River Nile flood plain in Egypt could not trace the very rapid mineral change observed in these soils. So, the clay mineralogy of the River Nile flood plain...Up till now all the clay mineral studies on the soils of the River Nile flood plain in Egypt could not trace the very rapid mineral change observed in these soils. So, the clay mineralogy of the River Nile flood plain soils in Sohag region, Egypt, has been studied using the method of numerical analysis of X-ray diffraction recordings （curve decomposition） as a new, powerful tool for precise mineral identification. The X-ray patterns of the studied soil clay fraction show that 2：1 clay minerals are much more abundant than kaolinite and that this clay fraction contains fair amounts of K-feldspar and quartz. XRD pattems obtained on the 〈 2 μm fraction of the River Nile sediments indicate the presence of smectite, mixed-layer illite-expanding minerals, kaolinite, mica-illite and chlorite. The decomposed XRD patterns reveal significant changes in the mineralogy of the clays. The major clay phases present in the 4-11 20 range are well crystallized illite （10 A）, poorly crystallized illite （10.2-10.4 A）, two mixed-layer I-S （illite/smectite） minerals, one with a peak near 13.5 A （rich-smectite） and the other near 11 A （rich-illite）.展开更多
Shoot density, standing crop （above- and below-ground biomass） and habitat of salt marsh grass Porteresia coarctata were investigated along the coast of Bakkhali estuary, Cox＇s Bazar, Bangladesh from January to Dec...Shoot density, standing crop （above- and below-ground biomass） and habitat of salt marsh grass Porteresia coarctata were investigated along the coast of Bakkhali estuary, Cox＇s Bazar, Bangladesh from January to December 2006. Shoot density of P. coarctata was influenced by season and was found to be higher （〉2 500 shoots/m2） in post-monsoon and minimal in monsoon season; plants were particularly active in vegetative propagation during pre-monsoon. Above-ground biomass was greater along the protected coast compared with the exposed one in this estuary. Below-ground biomass was higher （7.75-269.53 g DW/m2） than that above ground （2.20-114.75 g DW/m2）. Standing crops ofP. coarctata showed a negative relationship （R=-0.77; P〈0.05） with sedimentation rate, while seasonal activity influenced sedimentation. The recorded sedimentation rate was lower （6.09 mg/（cm2·d）） in pre-monsoon and highest （14.55 mg/（cm2·d）） in monsoon season. The mean value of pore water salinity was higher （34.25±65.05） during post-monsoon and lowest （18.0±3.71） in monsoon season. The soil was sandy clay in this P. coarctata bed; it consisted of 86% sand, 13% clay and 1% silt. Soil organic matter dropped during the monsoon season （0.78%-0.67%） and was highest （（2.17±1.42）%-（2.3±1.47）%） during post-monsoon, probably owing to accumulation of decomposed peat on the marsh surface. The mean pore water NH4-N concentration ranged from 2.444-1.65 to 3.33±1.82 μg/L, with a minimum air temperature of 22.09℃ in post-monsoon and a maximum of 31.16℃ in pre-monsoon. Variations of physico-chemical parameters in the soil, water, and climate governed biological parameters of P. coarctata in the Bakkhali estuary, and were comparable with estuarine environments elsewhere.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41076032,41430965)
文摘The South Yellow Sea(SYS) is strongly influenced by the substantial sediment loads of the Huanghe(Yellow)(including the modern Huanghe and abandoned old Huanghe subaqueous delta) and Changjiang(Yangtze) Rivers. However,the dispersal patterns of these sediments,especially in the western SYS,have not been clearly illustrated. In this study,we have analyzed clay minerals,detrital minerals,and grain sizes for 245 surface sediment samples(0–5 cm) collected from the western SYS. The clay minerals,on average,consist of 67% illite,14% smectite,11% chlorite,and 8% kaolinite. Clay minerals,detrital minerals,and grain size analyses of surface sediments,combined with water mass hydrology analysis,reveal that sediments in the western SYS are mainly derived from the modern Huanghe River,the abandoned subaqueous delta of the old Huanghe River,some material from the Changjiang,and coastal erosion. The clay minerals(especially illite and smectite) and quartz/feldspar ratio distribution patterns,reveal that the influence of modern Huanghe sediments can reach 35°N in the northwestern part of the study area,an influence that can be enhanced especially in winter owing to northerly winds. Conversely,sediments along the Jiangsu coast are mixed,in summer,with material from the Changjiang arriving via northward flow of Changjiang Diluted Water. The Subei Coastal Current carries the refreshed sediments northward into the western SYS. Sediment distribution and transport in the western SYS are mainly controlled by the oceanic circulation system that is primarily related to the monsoon.
文摘The clay minerals of more than 200 soil samples collected from various sites of Fujian Province were studied by the X-ray diffraction method and transmission electron microscopy to study their distribution and evolution. Montmorillonite was found in coastal solonchak, paddy soils derived from marine deposit, lacustrine deposit and river deposit, and some latentic red soil, red soil and yellow soil with a low weathering degree. Chlorite existed mainly in coastal solonchak and paddy soil developed from marine deposit. 1.4 nm intergradient mineral appeared frequently in yellow soil, red soil and latentic red soil. The content of l.4 nm intergradient mineral increased with the decrease of weathering degree from latentic red soil to red soil to yellow soil. Hydrous micas were more in coastal solonchak, paddy soils derived from marine deposit, lacustrine deposit and river deposit, and purple soil from purple shale than in other soils. Kaolinite was the most important clay mineral in the soils in this province. The higher the soil weathering degree, the more the kaolinite existed. From yellow soil to red soil to latentic red soil, kaolinite increased gradually. Kaolinite was the predominant clay mineral accompanied by few other minerals in typical latentic red soil. Tubular halloysite was a widespread clay mineral in soils of Fujian Province with varying quantities. The soil derived from the parent rocks rich in feldspar contained more tubular halloysite. Spheroidal halloysite was found in a red soil and a paddy soil developed from olivine basalt. Gibbsite in the soils in this district was largely 'primary gibbsite' which formed in the early weathering stage. Gibbsite decreased with the increase of weathering degree from yellow soil to red soil to latentic red soil. Goethite also decreased in the same sequence while hematite increased.
文摘In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental conditions. It is also important that the time required for transportation should be minimum. In this paper a method has been proposed for the minimization of transportation costs. Supply and transportation costs per unit of the quantities are also determined. The present study was carried out to evaluate the quality of gravel to know its suitability for aggregate (raw material for concrete and road). The samples of gravel were analyzed for petrographic, physical, mechanical and chemical properties. Samples were categorized as quartzite group and carbonate group according to ASTM standard 295. Among these, samples of quartzite group were found dominant. The petrography examination of gravels which was carried out constituted of opal, tridymite, chalcedony, crystobalite and alkali carbonates rocks. Those minerals react with alkalis in cement leading to expansion and cracking of concrete. Other components such as sulfides, sulfates, halites, iron oxides, clay minerals and anhydrites are examined, which might be present as coating and impurities. The present study indicated that all samples are suitable for concrete making and obtain the optimum solution for transporting these materials from quarries to cities with minimum cost according to Egyptian Code.
文摘Up till now all the clay mineral studies on the soils of the River Nile flood plain in Egypt could not trace the very rapid mineral change observed in these soils. So, the clay mineralogy of the River Nile flood plain soils in Sohag region, Egypt, has been studied using the method of numerical analysis of X-ray diffraction recordings （curve decomposition） as a new, powerful tool for precise mineral identification. The X-ray patterns of the studied soil clay fraction show that 2：1 clay minerals are much more abundant than kaolinite and that this clay fraction contains fair amounts of K-feldspar and quartz. XRD pattems obtained on the 〈 2 μm fraction of the River Nile sediments indicate the presence of smectite, mixed-layer illite-expanding minerals, kaolinite, mica-illite and chlorite. The decomposed XRD patterns reveal significant changes in the mineralogy of the clays. The major clay phases present in the 4-11 20 range are well crystallized illite （10 A）, poorly crystallized illite （10.2-10.4 A）, two mixed-layer I-S （illite/smectite） minerals, one with a peak near 13.5 A （rich-smectite） and the other near 11 A （rich-illite）.
基金the AWARE Foundation of Australiathe Ministry of Science and Information & Communication Technology of Bangladeshthe Bangladesh Nature Foundation (BNF)
文摘Shoot density, standing crop （above- and below-ground biomass） and habitat of salt marsh grass Porteresia coarctata were investigated along the coast of Bakkhali estuary, Cox＇s Bazar, Bangladesh from January to December 2006. Shoot density of P. coarctata was influenced by season and was found to be higher （〉2 500 shoots/m2） in post-monsoon and minimal in monsoon season; plants were particularly active in vegetative propagation during pre-monsoon. Above-ground biomass was greater along the protected coast compared with the exposed one in this estuary. Below-ground biomass was higher （7.75-269.53 g DW/m2） than that above ground （2.20-114.75 g DW/m2）. Standing crops ofP. coarctata showed a negative relationship （R=-0.77; P〈0.05） with sedimentation rate, while seasonal activity influenced sedimentation. The recorded sedimentation rate was lower （6.09 mg/（cm2·d）） in pre-monsoon and highest （14.55 mg/（cm2·d）） in monsoon season. The mean value of pore water salinity was higher （34.25±65.05） during post-monsoon and lowest （18.0±3.71） in monsoon season. The soil was sandy clay in this P. coarctata bed; it consisted of 86% sand, 13% clay and 1% silt. Soil organic matter dropped during the monsoon season （0.78%-0.67%） and was highest （（2.17±1.42）%-（2.3±1.47）%） during post-monsoon, probably owing to accumulation of decomposed peat on the marsh surface. The mean pore water NH4-N concentration ranged from 2.444-1.65 to 3.33±1.82 μg/L, with a minimum air temperature of 22.09℃ in post-monsoon and a maximum of 31.16℃ in pre-monsoon. Variations of physico-chemical parameters in the soil, water, and climate governed biological parameters of P. coarctata in the Bakkhali estuary, and were comparable with estuarine environments elsewhere.
