Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that fe...Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that feldspathic sandstone mixed with sand improved the sand stabilization in the governance of Mu Us Sandy Land in the fallow period. The sandy land remedied with feldspathic sandstone had big snow coverage, 25%-75% higher than normal sand; soil moisture losses slowed down, and moisture content rose by over 3 times; soil structure had been improved, and water stable aggregate content increased by 6.52%-18.04%; survival rate of protection forest increased to 85%; and ground flatness is less than 1%. The above conditions weakened sand rising conditions of Mu Us Sandy Land in the fallow period and formed two protective layers of snow cover and soil frozen layer under cold weather so as to prevent against wind erosion.展开更多
This research was conducted at the sand dunes stabilization research s tation in Baiji district, Iraq. Three techniques for sand dunes stabilization ar e selected: the first method is stabilization by clayey block ba...This research was conducted at the sand dunes stabilization research s tation in Baiji district, Iraq. Three techniques for sand dunes stabilization ar e selected: the first method is stabilization by clayey block barriers; the seco nd method is stabilization by dry planting of tamarix (tamarix articulata) cutti ngs and the third is stabilization by using cane branch barriers. Randomized sam ples were taken from the surface and subsurface layers of the stabilized and shi fting sand dunes to evaluate the effect of the three techniques on wind erosion parameters. The results indicate high significant differences between the wind e rosion parameters in the surface and subsurface layers in the stabilized sand du nes, while there are insignificant differences between the subsurface layer of t he stabilized dunes and the surface and subsurface layers in the active sand dun es. The results clarify the fact that there is an increase in the percentage of clay, silt, organic matter, mean weight diameter and the percentage of the dry a ggregates (>0.84 mm). A decrease is found in the rate of disaggregation for the dry aggregates in the samples of the surface layer of stabilized dunes when comp ared with the subsurface layer of stabilized dunes and the surface layer of the shifting sand dunes. There is a positive high significant correlation among the aggregate stability parameters and the percentage of clay and silt, and the cont ent of organic matter in the studied layers.展开更多
Shu 3 area has experienced many times of overall and local infill adjustments, and has always adopted a set of strata series of large sections of combined injection and production. There are great differences in the d...Shu 3 area has experienced many times of overall and local infill adjustments, and has always adopted a set of strata series of large sections of combined injection and production. There are great differences in the development status, water flooding degree and pressure maintenance level in the planar areas, especially in the central Du 18 well area where water flooding is serious, the deployment of new wells in the secondary development and the adjustment of injection and production well pattern are basically completed, and it is difficult to improve the development effect by relying solely on water flooding, and it is urgent to change the development mode. In this paper, the development effect of chemical flooding in sand-producing reservoirs is improved by means of fine reservoir research, optimization of formulation system, improvement of process technology and other means, starting from the production of well control sand to stabilize sand, polymer injection in injection wells to maintain viscosity, and improvement of reservoir production.展开更多
A new technique was introduced for sand stabilization and re-vegetation by use of lignin sand stabilizing material(LSSM). LSSM is a reconstructed organic compound with lignin as the most dominant component from the ex...A new technique was introduced for sand stabilization and re-vegetation by use of lignin sand stabilizing material(LSSM). LSSM is a reconstructed organic compound with lignin as the most dominant component from the extracts of black-liquor issued by straw pulp paper mills. Unlike the polyvinyl acetate or foamed asphalt commonly used for dune stabilization, the new material is plant-friendly and can be used with virescence actions simultaneously. The field experimental study was conducted since 2001 in China's Northwest Ningxia Hui Autonomous Region and has been proved that LSSM is effective in stabilizing the fugitive dunes, making the arenaceous plants survive and the bare dune vegetative. The advisable solution concentration is 2% and the optimal field spraying quantity is 2 5 L/m^2 The soil nutrients of the stabilized and greened dune, such as organic matter, available phosphorous and total nitrogen are all increased compared with the control treatment, which is certainly helpful to the growth of arenaceous plants. The technique is worthwhile to be popularized because it is provided not only a new method for desertification control but also an outlet for cleaning contaminants issued from the straw paper mills.展开更多
Six representative parent rocks of sand, including limestone, quartzite, gneisses, granite, Basalt and Marble were selected to conduct a systematical research on the effects of various lithologies of manufactured sand...Six representative parent rocks of sand, including limestone, quartzite, gneisses, granite, Basalt and Marble were selected to conduct a systematical research on the effects of various lithologies of manufactured sand on the workability, mechanism properties, volume stability and durability of manufacturedsand concrete. The experimental results show that the strength of manufactured-sand concrete is slightly higher than that of natural-sand concrete. Furthermore, substituting 15% cement of the concrete mixture with equal quantity of the six different lithology stone powder respectively, the data indicated that they can improve the concrete’s workability, postpone the plastic cracking time, enhance the anti-cracking grade, and have no obvious effect on the properties of antifreeze and sulfate attack resistance but reduce the capability to resist chloride ion penetration. Moreover, the differences in concrete’s workability, mechanism properties, volume stability and durability caused by various lithologies of manufactured sand and stone powder were not significant and the influence of lithology variety on the macro properties of concrete could be neglected eventually.展开更多
Biological soil crusts are essential components of arid ecosystems. We examined the variations in microfungal communities inhabiting different biological crust types in the vicinity of the Shapotou Research Station in...Biological soil crusts are essential components of arid ecosystems. We examined the variations in microfungal communities inhabiting different biological crust types in the vicinity of the Shapotou Research Station in the Tengger Desert, China. A total of 134 species from 66 genera were isolated using the soil dilution plate method. The mycobiota of the crusts from the Tengger Desert, similar to that of the Negev Desert in Israel, was dominated by melanin-containing species with large multicellular spores. Abundance of these xeric species increased spatially with increasing xeric conditions from moss-dominated to cyanobacterial crusts. Density of microfungal isolates displayed the opposite trend and was positively correlated with chlorophyll content, indicating the possible significant influence of organic matter content and wetness duration on fungal biomass. Within a chronosequence of the localities of different periods after sand stabilization with revegetation, little variations were revealed in species composition and isolate density of the crust microfungal communities, while a tendency towards a decrease in the community diversity level with the crust age was noted Microfungal communities from stabilized localities differed from those of the natural localities in abundance of the dominant and some frequent species, and in the fluctuations of diversity characteristics between the cyanobacterial and moss-dominated crusts. The variations in mycobiotie parameters in the soil crusts of the Tengger Desert were apparently associated with the topographically induced variations in abiotic conditions, while the differences in microfungal community of soil crusts between the Tengger and Negev deserts, such as the significantly higher abundance of thermotolerant species in the crusts of the Tengger Deserts, were caused by the principal differences in their precipitation regimes, associated with different rainy seasons, winter and summer in the Negev and Tengger deserts, respectively.展开更多
Longitudinal dunes are the most widespread dune types in the world sand seas but comprehensive study on the sand surface stability is scarce.The southern part of Gurbantnggt Desert is mainly covered by longitudinal du...Longitudinal dunes are the most widespread dune types in the world sand seas but comprehensive study on the sand surface stability is scarce.The southern part of Gurbantnggt Desert is mainly covered by longitudinal dune in which fixed and semi-fixed dunes occupy over 80%of the total area.Systematic analysis on the climatic conditions,the soil moisture and vegetation distributions,and the sand surface activities showed that the fixed and semi-fixed dunes are in a comprehensive low-energy wind environment.Snow cover and frozen soil provide a good protection to the ground surface in winter.The temporal distribution of precipitation and corresponding variation of temperature create a favorable condition for the desert plants growth,especially for the ephemeral plants.The occurrence of effective winds for sand moving in April to June coincides with the stage of relatively wet sand surface and good vegetation cover,which effectively keep the sand surface stable at the interdune and the plinth of the dunes.Activity sand surface appears only at the crest and the upper part of the sand dunes.展开更多
A series of tests were carried out on sulfate rich, high-plasticity clay and poorly-graded natural sand to study the effectiveness of a methylene diphenyl diisocyanate based liquid polymer soil stabilizer in improving...A series of tests were carried out on sulfate rich, high-plasticity clay and poorly-graded natural sand to study the effectiveness of a methylene diphenyl diisocyanate based liquid polymer soil stabilizer in improving the unconfined compressive strength （UCS） of freshly stabilized soils and aged sand specimens. The aged specimens were prepared by exposing the specimens to ultraviolet radiation, freeze-thaw, and wet-dry weathering. The polymer soil stabilizer also mitigated the swelling of the expansive clay. For clay, the observations indicated that the sequence of adding water and liquid polymer had great influence on the gained UGS of stabilized specimens. However, this was shown to be of little importance for sand. Furthermore, sand samples showed incremental gains in UCS when they were submerged in water. This increase was significant for up to 4 days of soaking in water after 4 days of ambient air curing. Conversely, the clay samples lost a large fraction of their UCS when soaked in water; however, their remaining strength was still considerable. The stabilized specimens showed acceptable endurance under weathering action, although sample yellowing due to ultraviolet radiation was evident on the surface of the specimens. Except for moisture susceptibility of the clay specimens, the results of this study suggested the liquid stabilizer could be successfully utilized to provide acceptable strength, durability and mitigated swelling.展开更多
基金The public welfare scientific research of Ministry of Land and Resources,No.201411008
文摘Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that feldspathic sandstone mixed with sand improved the sand stabilization in the governance of Mu Us Sandy Land in the fallow period. The sandy land remedied with feldspathic sandstone had big snow coverage, 25%-75% higher than normal sand; soil moisture losses slowed down, and moisture content rose by over 3 times; soil structure had been improved, and water stable aggregate content increased by 6.52%-18.04%; survival rate of protection forest increased to 85%; and ground flatness is less than 1%. The above conditions weakened sand rising conditions of Mu Us Sandy Land in the fallow period and formed two protective layers of snow cover and soil frozen layer under cold weather so as to prevent against wind erosion.
文摘This research was conducted at the sand dunes stabilization research s tation in Baiji district, Iraq. Three techniques for sand dunes stabilization ar e selected: the first method is stabilization by clayey block barriers; the seco nd method is stabilization by dry planting of tamarix (tamarix articulata) cutti ngs and the third is stabilization by using cane branch barriers. Randomized sam ples were taken from the surface and subsurface layers of the stabilized and shi fting sand dunes to evaluate the effect of the three techniques on wind erosion parameters. The results indicate high significant differences between the wind e rosion parameters in the surface and subsurface layers in the stabilized sand du nes, while there are insignificant differences between the subsurface layer of t he stabilized dunes and the surface and subsurface layers in the active sand dun es. The results clarify the fact that there is an increase in the percentage of clay, silt, organic matter, mean weight diameter and the percentage of the dry a ggregates (>0.84 mm). A decrease is found in the rate of disaggregation for the dry aggregates in the samples of the surface layer of stabilized dunes when comp ared with the subsurface layer of stabilized dunes and the surface layer of the shifting sand dunes. There is a positive high significant correlation among the aggregate stability parameters and the percentage of clay and silt, and the cont ent of organic matter in the studied layers.
文摘Shu 3 area has experienced many times of overall and local infill adjustments, and has always adopted a set of strata series of large sections of combined injection and production. There are great differences in the development status, water flooding degree and pressure maintenance level in the planar areas, especially in the central Du 18 well area where water flooding is serious, the deployment of new wells in the secondary development and the adjustment of injection and production well pattern are basically completed, and it is difficult to improve the development effect by relying solely on water flooding, and it is urgent to change the development mode. In this paper, the development effect of chemical flooding in sand-producing reservoirs is improved by means of fine reservoir research, optimization of formulation system, improvement of process technology and other means, starting from the production of well control sand to stabilize sand, polymer injection in injection wells to maintain viscosity, and improvement of reservoir production.
文摘A new technique was introduced for sand stabilization and re-vegetation by use of lignin sand stabilizing material(LSSM). LSSM is a reconstructed organic compound with lignin as the most dominant component from the extracts of black-liquor issued by straw pulp paper mills. Unlike the polyvinyl acetate or foamed asphalt commonly used for dune stabilization, the new material is plant-friendly and can be used with virescence actions simultaneously. The field experimental study was conducted since 2001 in China's Northwest Ningxia Hui Autonomous Region and has been proved that LSSM is effective in stabilizing the fugitive dunes, making the arenaceous plants survive and the bare dune vegetative. The advisable solution concentration is 2% and the optimal field spraying quantity is 2 5 L/m^2 The soil nutrients of the stabilized and greened dune, such as organic matter, available phosphorous and total nitrogen are all increased compared with the control treatment, which is certainly helpful to the growth of arenaceous plants. The technique is worthwhile to be popularized because it is provided not only a new method for desertification control but also an outlet for cleaning contaminants issued from the straw paper mills.
基金Funded by the National West Communication Construction Technology Project(No.2013 318 354 190)
文摘Six representative parent rocks of sand, including limestone, quartzite, gneisses, granite, Basalt and Marble were selected to conduct a systematical research on the effects of various lithologies of manufactured sand on the workability, mechanism properties, volume stability and durability of manufacturedsand concrete. The experimental results show that the strength of manufactured-sand concrete is slightly higher than that of natural-sand concrete. Furthermore, substituting 15% cement of the concrete mixture with equal quantity of the six different lithology stone powder respectively, the data indicated that they can improve the concrete’s workability, postpone the plastic cracking time, enhance the anti-cracking grade, and have no obvious effect on the properties of antifreeze and sulfate attack resistance but reduce the capability to resist chloride ion penetration. Moreover, the differences in concrete’s workability, mechanism properties, volume stability and durability caused by various lithologies of manufactured sand and stone powder were not significant and the influence of lithology variety on the macro properties of concrete could be neglected eventually.
基金the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists (No. 2011T1Z16)Israeli Ministry of Absorption for financial support of this research
文摘Biological soil crusts are essential components of arid ecosystems. We examined the variations in microfungal communities inhabiting different biological crust types in the vicinity of the Shapotou Research Station in the Tengger Desert, China. A total of 134 species from 66 genera were isolated using the soil dilution plate method. The mycobiota of the crusts from the Tengger Desert, similar to that of the Negev Desert in Israel, was dominated by melanin-containing species with large multicellular spores. Abundance of these xeric species increased spatially with increasing xeric conditions from moss-dominated to cyanobacterial crusts. Density of microfungal isolates displayed the opposite trend and was positively correlated with chlorophyll content, indicating the possible significant influence of organic matter content and wetness duration on fungal biomass. Within a chronosequence of the localities of different periods after sand stabilization with revegetation, little variations were revealed in species composition and isolate density of the crust microfungal communities, while a tendency towards a decrease in the community diversity level with the crust age was noted Microfungal communities from stabilized localities differed from those of the natural localities in abundance of the dominant and some frequent species, and in the fluctuations of diversity characteristics between the cyanobacterial and moss-dominated crusts. The variations in mycobiotie parameters in the soil crusts of the Tengger Desert were apparently associated with the topographically induced variations in abiotic conditions, while the differences in microfungal community of soil crusts between the Tengger and Negev deserts, such as the significantly higher abundance of thermotolerant species in the crusts of the Tengger Deserts, were caused by the principal differences in their precipitation regimes, associated with different rainy seasons, winter and summer in the Negev and Tengger deserts, respectively.
基金the National Key Basic Research Project(Grant No.G1999043504)the Knowledge Innovation Project ofCAS(Grant No.KZCX3-SW-326)the“Light of West China”Project of CAS for the talent training plan.
文摘Longitudinal dunes are the most widespread dune types in the world sand seas but comprehensive study on the sand surface stability is scarce.The southern part of Gurbantnggt Desert is mainly covered by longitudinal dune in which fixed and semi-fixed dunes occupy over 80%of the total area.Systematic analysis on the climatic conditions,the soil moisture and vegetation distributions,and the sand surface activities showed that the fixed and semi-fixed dunes are in a comprehensive low-energy wind environment.Snow cover and frozen soil provide a good protection to the ground surface in winter.The temporal distribution of precipitation and corresponding variation of temperature create a favorable condition for the desert plants growth,especially for the ephemeral plants.The occurrence of effective winds for sand moving in April to June coincides with the stage of relatively wet sand surface and good vegetation cover,which effectively keep the sand surface stable at the interdune and the plinth of the dunes.Activity sand surface appears only at the crest and the upper part of the sand dunes.
基金Alchemy Polymers Company,LLC for their financial support
文摘A series of tests were carried out on sulfate rich, high-plasticity clay and poorly-graded natural sand to study the effectiveness of a methylene diphenyl diisocyanate based liquid polymer soil stabilizer in improving the unconfined compressive strength （UCS） of freshly stabilized soils and aged sand specimens. The aged specimens were prepared by exposing the specimens to ultraviolet radiation, freeze-thaw, and wet-dry weathering. The polymer soil stabilizer also mitigated the swelling of the expansive clay. For clay, the observations indicated that the sequence of adding water and liquid polymer had great influence on the gained UGS of stabilized specimens. However, this was shown to be of little importance for sand. Furthermore, sand samples showed incremental gains in UCS when they were submerged in water. This increase was significant for up to 4 days of soaking in water after 4 days of ambient air curing. Conversely, the clay samples lost a large fraction of their UCS when soaked in water; however, their remaining strength was still considerable. The stabilized specimens showed acceptable endurance under weathering action, although sample yellowing due to ultraviolet radiation was evident on the surface of the specimens. Except for moisture susceptibility of the clay specimens, the results of this study suggested the liquid stabilizer could be successfully utilized to provide acceptable strength, durability and mitigated swelling.
