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Minimum Bedrock Exposure Ages and Their Implications:Larsemann Hills and Neighboring Bolingen Islands,East Antarctica

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Acta Geologica Sinica(English Edition) 2010年第3期84卷 543-548页

作者： HUANG Feixin LI Guangwei LIU Xiaohan KONG Ping JU Yitai David FINK FANG Aimin YU Liangjun Institute of Mineral Resources Research China Metallurgical Geology Bureau Beijing 100025 China Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Australian Nuclear Science and Technology Organization Menai NSW 2234 Australia Graduate University of the Chinese Academy of Sciences Beijing 100049 China

Considerable controversy exists over whether or not extensive glaciation occurred during the global Last Glacial Maximum（LGM） in the Larsemann *** this study we use the in situ produced cosmogenic nuclide ^（10）Be（half life 1.51 Ma） to provide minimum exposure ages for six bedrock samples and one erratic boulder in order to determine the last period of deglaciation in the Larsemann Hills and on the neighboring Bolingen *** bedrock samples taken from Friendship Mountain（the highest peak on the Mirror Peninsula,Larsemann Hills;～2 km from the ice sheet） have minimum exposure ages ranging from 40.0 to 44.7 *** erratic boulder from Peak 106（just at the edge of the ice sheet） has a younger minimum exposure age of only 8.8 *** minimum exposure ages for two bedrock samples from Blundell Peak（the highest peak on Stornes Peninsula,Larsemann Hills;～2 km from the ice sheet） are about 17 and 18 *** the Bolingen Islands（southwest to the Larsemann Hills;～10 km from the ice sheet）,the minimum exposure age for one bedrock sample is similar to that at Friendship Mountain（i.e.,44 ka）.Our results indicate that the bedrock exposure in the Larsemann Hills and on the neighboring Bolingen Islands commenced obviously before the global LGM（i.e.,20-22 ka）,and the bedrock erosion rates at the Antarctic coast areas may be obviously higher than in the interior land.

关键词： east Antarctica Larsemann Hills Bolingen Islands 1~Be exposure age erosion rate

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Optimization of operating conditions in the steam turbine blade cascade using the black-box method

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Propulsion and Power Research 2023年第4期12卷 467-485页

作者： Vahid Sadrian Esmail Lakzian Davood Hoseinzade Behrad Haghighi M.M.Rashidi Heuy Dong Kim Center of Computational Energy Department of Mechanical EngineeringHakim Sabzevari UniversitySabzevarIran Department of Mechanical Engineering Andong National UniversityAndongSouth Korea Department of Mechanical Engineering Vali-e-Asr University of RafsanjanRafsanjanIran Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China Faculty of Science University of JohannesburgPO Box 524Auckland Park 2006South Africa

Water droplets cause corrosion and erosion,condensation loss,and thermal efficiency reduction in low-pressure steam *** this study,multi-objective optimization was carried out using the black-box method through the automatic linking of a genetic algorithm(GA)and a computational fluid dynamics(CFD)code to find the optimal values of two design variables(inlet stagnation temperature and cascade pressure ratio)to reduce wetness in the last stages of *** wet steam flow numerical model was used to calculate the optimization parameters,including wetness fraction rate,mean droplet radius,erosion rate,condensation loss rate,kinetic energy rate,and mass flow *** the validation results showed a good agreement between the experimental data and the numerical *** to the optimization results,the inlet stagnation temperature and the cascade pressure ratio were proposed to be 388.67(K)and 0.55(-),*** particular,the suggested optimaltemperature and pressure ratio improved the liquid mass fraction and mean droplet radius by about 32%and 29%,***,in the identified optimal operating state,the ratios of erosion,condensation loss,and kinetic energy fell by 76%,32.7%,and 15.85%,respectively,while the mass flow rate ratio rose by 0.68%.

关键词： Black-box optimization Wet steam flow Steam turbine cascade erosion rate Condensation loss

National assessment of soil erosion and its spatial patterns in China

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Ecosystem Health and Sustainability 2015年第4期1卷 29-39页

作者： Enming Rao Yi Xiao Zhiyun Ouyang Xinxiao Yu State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085 China University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Soil and Water Conservation and Desertification Combating of the Ministry of Education School of Soil and Water ConservationBeijing Forestry UniversityBeijing 100083 China

The spatial patterns of soil erosion(SE)are an important part of ecological security patterns and critical to erosion *** assessed the SE and its spatial distribution in China based on geographic information system(GIS)and spatial data sets using the Universal Soil Loss Equation(USLE).The soil erosion area(SEA)and soil erosion amount(SEM)totaled 173.06 million ha and 8.87 billion Mg,respectively,with an average soil erosion rate(SER)of 9.39 Mg·ha^(-1)·yr^(-1).Slight erosion dominated from the aspect of SEA,whereas extreme erosion contributed the most in terms of *** heterogeneity in soil erosion was obvious in China,with heavily eroded areas mainly concentrated in the Loess Plateau,the Three Gorges reservoir area,and the hot,dry valley of the Jinsha ***,the provinces of Tibet,Sichuan,Yunnan,Xinjiang,Inner Mongolia,Gansu,Shaanxi,Shanxi,Guizhou,and Guangxi,and the basins of the Yangtze River,Yellow River,and southwestern rivers made a large contribution to the SEA and ***,soil erosion increased,then decreased with increasing slope and *** of 15-25°and 8-15°and elevations of 1000-2000 m were the most seriously *** and grassland ecosystems were major sources of SE,with their SEA and SEM accounting for 64.44%and 77.96%of the *** study revealed the current situation and spatial characteristics of SE in China on the national scale,which can serve as a scientific basis for regional SE control and decision-making policy.

关键词： China erosion rate GIS national risk assessment soil erosion spatial pattern Universal Soil Loss Equation

Gravity erosion and lithology in Pisha sandstone in southern Inner Mongolia

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Journal of Groundwater Science and Engineering 2015年第1期3卷 45-58页

作者： GUO Jiao SHI Ying-chun WU Li-jie Institute of Hydrogeology and Environmental Geology CAGS

Pisha sandstone is a soft rock found in the southern zone of the Inner Mongolia Autonomous Region of Inner Mongolia. The presence of soft Pisha sandstone in the middle reaches of the Yellow River coincides with large areas of bedrock erosion in the river’s basin, with the average total erosion modulus as high as 44 570 t/(km^2·a). Such high levels of erosion are one of the main sources of coarse mud and sands in the Yellow River. erosion by gravitational forces such as snow glide and landslip are the main erosion types in Pisha sandstone region. The gravity erosion modulus can be as high as 25 615 t/(km^2·a), accounting for 30.6% of the total average erosion. Our paper investigates the characteristics of Pisha sandstone in relation to the development of gravity erosion mechanisms. We conducted field investigations in Pisha sandstone region for original state rock sampling. Test results from analyses of the rock properties indicate that the mineral composition, structure and microstructure characteristics of Pisha sandstone determine its varying capacity to resist weathering. Degrees of weathering in slightly different lithological layers of Pisha sandstone lead to different erosion rates. In this way, erosion forces combined with the varying lithological strata in the rock aggravate gravitational erosion in Pisha sandstone.

关键词： Pisha sandstone Rock properties erosion rate Gravity erosion Micro-structure

ASSESSMENT OF SOIL LOSS ON UNCULTIVATED SLOPE LAND BY USING 137CS TECHNIQUE IN THE UPPER YANGTZE RIVER BASIN OF CHINA

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International Journal of Sediment Research 2004年第1期19卷 60-65页

作者： Mingyi FENG, Xinbao ZHANG , Anbang WEN and Xiubin HE China West Normal University, Nanchong 637002, E-mail: mingyifeng2004@*** State Key Laboratory of Soil and Dryland Farming on Loess Plateau, IWSC, CAS, Yangling 710075 Institute of Mountain Hazards and Environment, Chinese Academy of Sciences,Chengdu 610041 China West Normal University Nanchong637002 State Key Laboratory of Soil and Dryland Farming on Loess Plateau IWSC CAS Yangling 710075 Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041 Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041

Radionuclides are used as tracers of sediments in areas where no plot data or field monitoring data are not available. Caesium-137 can provide important information on both soil loss rates and sediment sources. The 137Cs technique is employed to assess soil erosion rates in forest and grass lands in the Upper Yangtze River Basin, China. The study area includes 6 forestlands and 4 grasslands in 8 counties and cities over the eastern part of the basin. The 137Cs reference inventories ranged from 620.9 Bq m-2 to 2560.3 Bq m-2. For the 6 forestlands, the average 137Cs inventory over a field ranges from 960.8 Bq m"2 to 2560.3 Bq m-2. The average erosion rate is estimated from the 137Cs measurements between 0 to 588 t km-2yr-1. For the 4 grasslands, the average 137Cs inventory ranges from 119.0 Bq m-2 to 869.7 Bq m-2. The average rate of erosion from grassland varies from 0 to 4435 t km-2 yr-1. Where the erosion was more severe, the 137Cs inventory was lower. The results showed that there is no clear relation

关键词： erosion rate Uncultivated land 137 Cs technique Upper Yangtze River

INVESTIGATIONS ON erosionAL PROCESSES OF COHESIVE SEDIMENT USING AN IN-SITU MEASURING DEVICE

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International Journal of Sediment Research 1997年第3期 139-147页

作者： Rosi LIEM Research Engineers, Institute of Hydraulic Engineering and Water Resources Management, Aachen Univer-s of Technology, Germany Volker SPORK Research Engineers, Institute of Hydraulic Engineering and Water Resources Management, Aachen Univer-

Transport Phenomena of cohesive sediments have a significant influence on morphological changes in rivers. At the institute of Hydraulic Engineering (IWW) at Aachen University mainly laboratory Studies on cohesive sediments have been carried out. These experiments as well as earlier approaches indicate the strong dependency on external conditions. Since processes in nature cannot identically be ressembled in the laboratory, a device for in-situ investigations was constructed. Main unit of the device is the bottomless sampling chamber which has to be fixed on the sediment bed. The current inside the cylinder is generated by a propeller. Therefore shear stresses had to be calibrated against propeller revolutions. There is also a concentration meter within the sampling chamber to obtain erosion rates. To enable comparison, in-situ investigations have been carried out in a German reservoir where samples had also been taken for laboratory investigations in the annular flume. Results prooving the necessity of field studies where very convncing, since a very high reproducibility was attained.

关键词： erosion rate Measurement device Cohesive sediments Morphological changes In-situ investigations

Impacts of Agricultural Activities on Land Degradation along the Bomboré River in Burkina Faso

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Agricultural Sciences 2023年第2期14卷 176-195页

作者： Joseph Nomwindé Kabore Elie Serge Gaëtan Sauret Wennegouda Jean Pierre Sandwidi Raoul Christian Ouedraogo Brahima Sorgho Senghor Campus Senghor University Ouagadougou Burkina Faso General Office of Plants Productions Ministry of Agriculture Animal and Fishery Resources Ouagadougou Burkina Faso National Center for Scientific and Technological Research/National Institute for the Environment and Agricultural Research Farak&#244ba Research Station Bobo Dioulasso Burkina Faso Higher School of Engineering University of Fada N’Gourma Fada N’Gourma Burkina Faso Alliance for the Green Revolution Ouagadougou Burkina Faso Molecular Chemistry and Materials Laboratory Joseph KI-ZERBO University Ouagadougou Burkina Faso

Land along the Bomboré River in the rural commune of Mogtédo in Burkina Faso is experiencing degradation. The explanatory causes of this degradation constitute the subject of this study. To do this, a survey was conducted among agricultural producers deployed along the watercourse. Soil profiles were described and samples were taken to analyze pH, soil organic carbon, soil organic matter, total nitrogen, and texture. The RUSLE model approach based on landstat8 OLI/TIRS and SRTM satellite images dated December 17, 2021 with fairly good radiometric, spatial, and spectral resolution was used to calculate the land loss rate. In terms of results, the potentially irrigable areas that spread out on both sides of the banks of the river cover 209.23 ha with a perimeter of 6.16 km. The number of irrigators is 26 producers and they grow 17.92 ha of vegetables. Soil analyzes indicate the presence of a moderate acid on the vertisol with a pH between 5.57 and 5.86. On the depth 0 - 30 cm of the horizon, the color of the horizons ranges from 5YR4/2 on the talweg and on the right bank to 7.5YR3/2 on the left bank and presents no risk of salinity because the electrical conductivity measured is less than 1dS/cm. The diagnosis of hydromechanical equipment shows that producers use 46 motor pumps for irrigation, of which 15 motor pumps run on gasoline and 31 motor pumps on butane gas with a ratio of 1.7 motor pumps per producer. The number of Polyvinyl Chloride (PVC) pipes used by producers in combination with a motor pump gives an average of 44 per farmer. In terms of mineral fertilization, the gross doses used by producers are 415.53 kg/ha of NPK and 201.55 kg/ha of urea, while the quantities of phytosanitary products are 3.99 l/ha of pesticides and 1.42 l/ha of herbicides. Agricultural activities emit about 222,436.66 kgCO2eq into the atmosphere, whose emissions from motor pumps represent 84.52% of these total emissions. The land loss estimate gives an average rate of 2.30

关键词： Agricultural Irrigation Land Degradation RUSLE Model erosion rate Environment

SEDIMENT PROPERTIES AND DYNAMICS IN THE TAIHU LAKE,CHINA

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International Journal of Sediment Research 2006年第4期21卷 312-320页

作者： Liancong LUO1, Boqiang QIN2, Guang GAO3, Guangwei ZHU4, and Jinshan ZHANG51 Assis. Prof., 2,3Prof.,4 Assoc. Prof., Nanjing Institute of Geography and Limnology, CAS, Nanjing 210008, China 5 Prof., Nanjing Institute of Hydrological Sciences, Ministry of Water Resources, Nanjing 210024, China Nanjing Institute of Geography and Limnology CASNanjing 210008China Nanjing Institute of Hydrological Sciences Ministry of Water ResourcesNanjing 210024China

Time-series measurements of wave, current and suspended sediment concentration (SSC) weremade at three sites (Sites 1-3) and sediment samples were collected at different locations (Sites 4-7)in Lake Taihu. The significant wave height, length and period during the observation were 0.155 m,3.45 m and 1.9 s and the mean current speed was 0.08 m/s. The size distribution results show thatthe sediment is well sorted, coarse-skewed and very leptokurtic in the upper 10 cm and clay andfine silt can account for more than 70 % of the total within this depth. The median size remainsconstant vertically in the top 10 cm in the eastern, southern, and northern areas of the lake, butchanges significantly in the eastern area resulting from the short retention time of water in this *** realistic settling velocity of suspended particles varies in the range of 0.01~0.05 cm s-1 andthey sink in a flocculated form rather than individually. Based on a simple mass flux model, thesediment erosion rate was estimated to range between 10-7 and 10-5 kg/m2.s. The results in thisstudy can be a great contribution to the development of a sediment transportation model in LakeTaihu.

关键词： Sediment Resuspension erosion rate Settling velocity Lake Taihu

erosion in northwest Tibet from in-situ-produced cosmogenic 10Be and 26Al in bedrock

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Erosion in northwest Tibet from in-situ-produced cosmogenic ...