Composites of montmorillonite clay and sawdust were prepared with the desired result being having new materials which burn longer than unmodified sawdust. The three forms of clay used for preparation of composites wer...Composites of montmorillonite clay and sawdust were prepared with the desired result being having new materials which burn longer than unmodified sawdust. The three forms of clay used for preparation of composites were unmodified montmorillonite, mono-ionic montmorillonite and organically modified montmorillonite. Montmorillonite clay was converted to mono-ionic clay by ion exchange with sodium using a sodium chloride solution. The mono-ionic clay was organically modified with an organic surfactant, methyl triphenyl phosphonium bromide. Nanocomposites were then prepared by combining the modified and raw forms of the clay with sawdust. The solution blending method was used to make the nanocomposites. The samples were analysed using thermogravimetric analysis and cone calorimetry. The studies showed that the nanocomposite which was made from sawdust and 1% organically modified clay had the most improved results in terms of burning time and thermal stability, as well as giving a calorific value closest to unmodified sawdust and the least amount of residue.展开更多
Unsaturated shallow soil deposits may be affected by either superficial soil erosion or shallow landslides in adjacent or overlapping source areas and in different seasons when a different soil suction exists.The trig...Unsaturated shallow soil deposits may be affected by either superficial soil erosion or shallow landslides in adjacent or overlapping source areas and in different seasons when a different soil suction exists.The triggering analysis of both these processes is a relevant issue for the hazard analysis while the literature mostly provides specific approaches for erosion or for landslides.The paper proposes a largearea analysis for a case study of Southern Italy,consisting of unsaturated shallow deposits of loose pyroclastic(air-fall) volcanic soils that have been repeatedly affected by erosion and landslides in special seasons.For a past catastrophic event, the simulated source areas of shallow landslides are smaller than those observed in the field while the simulated eroded areas with thickness greater than 5cm are comparable with the in-situ evidences, if the analysis takes into account high rainfall intensity and a spatially variable soil cover use.More in general, the results of the paper are consistent with the previous literature and also provide a methodological contribution about the application of distinct tools over large area.The added value is that the paper shows how the combination of distinct large-area analyses may help with understanding the dominant slope instability mechanisms.Only once this goal is fully achieved, can specific physically-based analyses be confidently performed at detailed scales and for smaller specific areas.展开更多
Major oxides,as well as trace elements (including rare earth elements) compositions have been analyzed for the mixosedimentites from Neoproterozoic Jiayuan Formation in northern Anhui,China. The results show that the ...Major oxides,as well as trace elements (including rare earth elements) compositions have been analyzed for the mixosedimentites from Neoproterozoic Jiayuan Formation in northern Anhui,China. The results show that the concentrations of elements are closely related to the relative proportions of carbonates and terrigenous detritus (varying from 2/3 to 1/9 based on petrographic study). The ratios between some immobile elements (e.g. La,Th,Zr and Sc) are constant and then can be used as tracers for the discrimination of provenance and tectonic setting of terrigenous detritus. The results indicate that the terrigenous detritus mainly came from the felsic volcanics related to continental arc,with minor contribution from the old basement. Combined with recent research progresses,these mixosedimentites imply that the Neoproterozoic sedimentation in northern Anhui was probably taken place in a back arc basin during the convergence of Rodinia super continent between 1.0 and 0.8 Ga.展开更多
The shape,texture,content and REE characteristics of zircons from the O2tnd-1,O3tnd-2,O3tnd-3pyroclastic rock of Tanjianshan Group on the north margin of Qaidam Basin indicate that the O2-3tndis the product of volcani...The shape,texture,content and REE characteristics of zircons from the O2tnd-1,O3tnd-2,O3tnd-3pyroclastic rock of Tanjianshan Group on the north margin of Qaidam Basin indicate that the O2-3tndis the product of volcanism during the transitional period from ocean-land interim crust to oceanic crust.The U-Pb surface ages obtained from O3tnd-2and O3tnd-3can be divided into 9 groups,every age group coincides with the period when significant tectonic-heat event took place at Oulongbuluke micro-continental base of northern Qaidam,suggesting that the base rocks have provided materials for the formation of sedimentary and volcanic rock in O2-3tnd.The volcanic rocks of O3tnd-3formed at 440 Ma,with time gap 46 Ma to those of O1tna-1and O3tnd-3may represent the minor period that Xitieshan back-arc extension have lasted,the scale of back-arc basin that formed in Xitieshan extension may approach to 1 400 km.Based on the test of ithochemistry data for major elements and analysis of Sr isotope geochemistry for the clastic sedimentary rock in O1tna-2and O3tnd-2,the authors get the conclusion that the O1tna-2and O3tnd-2of Tanjianshan Group may form in back-arc basin environment,while the lithology difference between these two formations may reflect the changes of geodynamic processes as the diagenesis tectonic environment transformed from continental margin depression to adjacent sea basin.展开更多
The composition of single-grain detrital zircons is an effective provenance indicator of loess,and sheds new light on dust formation and transportation.Here we review the features of detrital zircons and their use as ...The composition of single-grain detrital zircons is an effective provenance indicator of loess,and sheds new light on dust formation and transportation.Here we review the features of detrital zircons and their use as a provenance indicator,including internal structure,trace element,U-Pb age spectrum and Hf isotopic compositions,and present a case study from the Horqin sandy land and its surrounding loess.The loess samples have detrital zircon age peaks in range of 2600-2300,2100-1600,and 600-100 Ma,of which the 2600-2300 Ma zircon grains mainly have positive Hf(t) values(3.4-8.7),the 2100-1600 Ma zircon grains mainly have negative Hf(t) values(10.1-6.8),and the 600-100 Ma zircon grains have a variable Hf(t) values ranging from 21 to 15.9.The detrital zircon signatures of the loess are similar to the Horqin sandy land,but clearly different from the Chinese Loess Plateau and central-western deserts,implying that the loess is transported mainly from the Horqin sandy land in the Last Glacial period.Comparing these with neighboring tectonic units,we found that zircon populations at 2600-2300,2100-1600,and 600-100 Ma with negative Hf(t) values may come from the northeast North China Craton(NCC),and those at 600-100 Ma with positive Hf(t) values may come from the east Central Asian Orogenic Belt(CAOB).It is estimated that the two sources contribute equally to the Horqin sandy land and the surrounding loess.展开更多
Weathered clastic crust can be subdivided into weathered clay and leached zone in terms of variable weathering of different minerals and mobility of weathered products.On the basis of clastic outcrops and well cores i...Weathered clastic crust can be subdivided into weathered clay and leached zone in terms of variable weathering of different minerals and mobility of weathered products.On the basis of clastic outcrops and well cores in the Junggar Basin,the dark red Fe-rich weathered clay is formed in an arid environment,whereas the light blue Al-rich weathered clay under humid conditions.According to the geochemical analysis,a new weathering index for weathered clastic crust is built mainly on Fe and Al contents,accurately indicating the weathered clay,sandy leached zone,and muddy leached zone in the Junggar Basin.The breaking pressure of weathered clay is rather large,the same as that of normal muddy cap,effectively to seal oil or gas.The porosity of underlying leached zone is greatly enhanced by weathering and leaching,but its permeability is a function of clay mineral content,i.e.,the higher the clay content,the worse the permeability.Weathered crust provides effective sealing conditions for both top and bottom layers of a petroleum reservoir,and is important in the clastic hydrocarbon exploration.展开更多
文摘Composites of montmorillonite clay and sawdust were prepared with the desired result being having new materials which burn longer than unmodified sawdust. The three forms of clay used for preparation of composites were unmodified montmorillonite, mono-ionic montmorillonite and organically modified montmorillonite. Montmorillonite clay was converted to mono-ionic clay by ion exchange with sodium using a sodium chloride solution. The mono-ionic clay was organically modified with an organic surfactant, methyl triphenyl phosphonium bromide. Nanocomposites were then prepared by combining the modified and raw forms of the clay with sawdust. The solution blending method was used to make the nanocomposites. The samples were analysed using thermogravimetric analysis and cone calorimetry. The studies showed that the nanocomposite which was made from sawdust and 1% organically modified clay had the most improved results in terms of burning time and thermal stability, as well as giving a calorific value closest to unmodified sawdust and the least amount of residue.
文摘Unsaturated shallow soil deposits may be affected by either superficial soil erosion or shallow landslides in adjacent or overlapping source areas and in different seasons when a different soil suction exists.The triggering analysis of both these processes is a relevant issue for the hazard analysis while the literature mostly provides specific approaches for erosion or for landslides.The paper proposes a largearea analysis for a case study of Southern Italy,consisting of unsaturated shallow deposits of loose pyroclastic(air-fall) volcanic soils that have been repeatedly affected by erosion and landslides in special seasons.For a past catastrophic event, the simulated source areas of shallow landslides are smaller than those observed in the field while the simulated eroded areas with thickness greater than 5cm are comparable with the in-situ evidences, if the analysis takes into account high rainfall intensity and a spatially variable soil cover use.More in general, the results of the paper are consistent with the previous literature and also provide a methodological contribution about the application of distinct tools over large area.The added value is that the paper shows how the combination of distinct large-area analyses may help with understanding the dominant slope instability mechanisms.Only once this goal is fully achieved, can specific physically-based analyses be confidently performed at detailed scales and for smaller specific areas.
基金supported by the National Nature Sciences Foundation of China( 40873015)the Science Research Fundation ( Ph.D) of Suzhou University ( 2009jb04)the Out-standing Young Talent Foundation of Colleges and Universities in Anhui ( 2010SQRL190)
文摘Major oxides,as well as trace elements (including rare earth elements) compositions have been analyzed for the mixosedimentites from Neoproterozoic Jiayuan Formation in northern Anhui,China. The results show that the concentrations of elements are closely related to the relative proportions of carbonates and terrigenous detritus (varying from 2/3 to 1/9 based on petrographic study). The ratios between some immobile elements (e.g. La,Th,Zr and Sc) are constant and then can be used as tracers for the discrimination of provenance and tectonic setting of terrigenous detritus. The results indicate that the terrigenous detritus mainly came from the felsic volcanics related to continental arc,with minor contribution from the old basement. Combined with recent research progresses,these mixosedimentites imply that the Neoproterozoic sedimentation in northern Anhui was probably taken place in a back arc basin during the convergence of Rodinia super continent between 1.0 and 0.8 Ga.
基金Supported by the National Natural Science Foundation of China(No.41172087)the Fundamental Research Funds for the Central Universities(No.CUG090102)
文摘The shape,texture,content and REE characteristics of zircons from the O2tnd-1,O3tnd-2,O3tnd-3pyroclastic rock of Tanjianshan Group on the north margin of Qaidam Basin indicate that the O2-3tndis the product of volcanism during the transitional period from ocean-land interim crust to oceanic crust.The U-Pb surface ages obtained from O3tnd-2and O3tnd-3can be divided into 9 groups,every age group coincides with the period when significant tectonic-heat event took place at Oulongbuluke micro-continental base of northern Qaidam,suggesting that the base rocks have provided materials for the formation of sedimentary and volcanic rock in O2-3tnd.The volcanic rocks of O3tnd-3formed at 440 Ma,with time gap 46 Ma to those of O1tna-1and O3tnd-3may represent the minor period that Xitieshan back-arc extension have lasted,the scale of back-arc basin that formed in Xitieshan extension may approach to 1 400 km.Based on the test of ithochemistry data for major elements and analysis of Sr isotope geochemistry for the clastic sedimentary rock in O1tna-2and O3tnd-2,the authors get the conclusion that the O1tna-2and O3tnd-2of Tanjianshan Group may form in back-arc basin environment,while the lithology difference between these two formations may reflect the changes of geodynamic processes as the diagenesis tectonic environment transformed from continental margin depression to adjacent sea basin.
基金supported by Young Scholars of the National Natural Science Foundation of China (Grant No.40802037)National Basic Research Program of China (Grant No.2010CB950204)Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. 80972970)
文摘The composition of single-grain detrital zircons is an effective provenance indicator of loess,and sheds new light on dust formation and transportation.Here we review the features of detrital zircons and their use as a provenance indicator,including internal structure,trace element,U-Pb age spectrum and Hf isotopic compositions,and present a case study from the Horqin sandy land and its surrounding loess.The loess samples have detrital zircon age peaks in range of 2600-2300,2100-1600,and 600-100 Ma,of which the 2600-2300 Ma zircon grains mainly have positive Hf(t) values(3.4-8.7),the 2100-1600 Ma zircon grains mainly have negative Hf(t) values(10.1-6.8),and the 600-100 Ma zircon grains have a variable Hf(t) values ranging from 21 to 15.9.The detrital zircon signatures of the loess are similar to the Horqin sandy land,but clearly different from the Chinese Loess Plateau and central-western deserts,implying that the loess is transported mainly from the Horqin sandy land in the Last Glacial period.Comparing these with neighboring tectonic units,we found that zircon populations at 2600-2300,2100-1600,and 600-100 Ma with negative Hf(t) values may come from the northeast North China Craton(NCC),and those at 600-100 Ma with positive Hf(t) values may come from the east Central Asian Orogenic Belt(CAOB).It is estimated that the two sources contribute equally to the Horqin sandy land and the surrounding loess.
基金supported by National Science and Technology Major Projects(Grant No.2011ZX05001-003)
文摘Weathered clastic crust can be subdivided into weathered clay and leached zone in terms of variable weathering of different minerals and mobility of weathered products.On the basis of clastic outcrops and well cores in the Junggar Basin,the dark red Fe-rich weathered clay is formed in an arid environment,whereas the light blue Al-rich weathered clay under humid conditions.According to the geochemical analysis,a new weathering index for weathered clastic crust is built mainly on Fe and Al contents,accurately indicating the weathered clay,sandy leached zone,and muddy leached zone in the Junggar Basin.The breaking pressure of weathered clay is rather large,the same as that of normal muddy cap,effectively to seal oil or gas.The porosity of underlying leached zone is greatly enhanced by weathering and leaching,but its permeability is a function of clay mineral content,i.e.,the higher the clay content,the worse the permeability.Weathered crust provides effective sealing conditions for both top and bottom layers of a petroleum reservoir,and is important in the clastic hydrocarbon exploration.
