Sediment resuspension in tidally dominated coastal environments: new insights into the threshold for initial movement   总被引：2，自引：1，他引：1  

Yang Yang  Ya Ping Wang  Shu Gao  Xiao Hua Wang  Ben Wei Shi  Liang Zhou  Dan Dan Wang  Chen Dai  Gao Cong Li 《Ocean Dynamics》2016,66(3):401-417

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Use of geoinformatics for inter-basin water transfer assessment     

Niladri Gupta  Petter Pilesjo  Ben Maathuis 《Water Resources》2010,37(5):623-637

Fresh water availability and demand are unevenly distributed both temporally and geographically. Furthermore, the availability of fresh water has remained more or less constant, while the demand for clean water is steadily increasing. With demand surpassing supply, an integrated water resource management approach is required to ensure even distribution of potable water to all levels of society while protecting the environment. Inter-basin water transfer (IBWT) is an approach being applied in various countries around the world, with varying environmental and social implications. The Interlinking of Rivers (ILR) scheme is an example of such a project being planned in India. The research described in this paper was based on the ILR project and includes an assessment of the IBWT programme in some of the tributaries of the Brahmaputra and Ganga Rivers in the eastern part of India, covering the district of Jalpaiguri, West Bengal, India. Geoinformation has been used in association with physical and socio-economic factors to identify potential dam and reservoir sites and to delineate the optimal route for canals to transfer water from the Brahmaputra basin to the Ganga basin for further transportation to the water-deficient regions of India.  相似文献   

滇西古特提斯多岛洋的结构及其南北延伸   总被引：42，自引：3，他引：39  

刘本培  冯庆来  C.CHONGLAKMANI  D.HELMCKE 《地学前缘》2002,9(3):161-171

在深化滇西古特提斯构造古地理格局研究基础上 ,提出了区分多岛洋与多岛海的时、空尺度标准。根据藏北羌塘、泰国北部与滇西古特提斯沉积地质学的比较研究 ,论证了滇西昌宁—孟连带北延连接冈玛错缝合带 ,南延与泰国北部隐蔽缝合带相接。泰国东北部著名的难河—程逸缝合带北延很可能潜伏于思茅盆地中新生代红层之下 ,因此古特提斯阶段并不存在稳定的“思茅地块”。泰国西北部湄萨良带存在洋盆硅质岩、海山碳酸盐岩和被动陆缘碎屑岩的构造混杂沉积组合 ,原属“泥盆系”的硅质岩中已发现早石炭世和晚三叠世卡尼期放射虫动物群 ,启示了古特提斯东段存在双子星座式主支洋盆的构造古地理格局。湄萨良带北延最可能与保山地块、腾冲地块之间的潞西三台山蛇绿混杂带相连。滇西北地区原属晚三叠世哈工组内侏罗纪放射虫化石的发现等 ,启示了青藏高原三江带在古、新特提斯转折期古地理演化的复杂性  相似文献   

A Simulation Model for the Evaluation of the Electrical Power Potential Harnessed by a Marine Current Turbine     

Ben Elghali  S.E. Balme  R. Le Saux  K. El Hachemi Benbouzid  M. Charpentier  J.F. Hauville  F. 《Oceanic Engineering, IEEE Journal of》2007,32(4):786-797

This paper deals with the development of a Matlab-Simulink model of a marine current turbine system through the modeling of the resource and the rotor. The simulation model has two purposes: performances and dynamic loads evaluation in different operating conditions and control system development for turbine operation based on pitch and speed control. In this case, it is necessary to find a compromise between the simulation model accuracy and the control-loop computational speed. The blade element momentum (BEM) approach is then used for the turbine modeling. As the developed simulation model is intended to be used as a sizing and site evaluation tool for current turbine installations, it has been applied to evaluate the extractable power from the Raz de Sein (Brittany, France). Indeed, tidal current data from the Raz de Sein are used to run the simulation model over various flow regimes and yield the power capture with time.  相似文献   

Statistical Analysis of Nitrate Movement through the Soil in Central Kansas     

Ben?Harp  Jeremy?Hogue  Logan?Peck  Drew?SpainEmail author 《Natural Resources Research》2005,14(2):101-107

An earlier investigation by the Kansas Geological Survey in central Kansas studied the movement of nitrate from fertilizer through soil into the groundwater. Nitrate concentrations in soil water were measured on samples collected at three locations during a three-year span, from sets of lysimeters buried at different depths. Although patterns seemed apparent in the resulting measurements, no statistical analyses were performed to test their significance; this re-study of the data uses analyses of variance to test for differences in nitrate concentration attributable to time and to depth in the soil. The mean nitrate concentration of samples collected in the first year of the experiment was significantly higher than the means of second and third year samples at all three locations, perhaps reflecting the confounding influence of a previous flooding experiment. ANOVAs of depth across years determined few significant differences in nitrate concentration with depth. The wintertime gap in measurements and unequal sampling through time precludes formal time-series analyses, but graphs of concentration versus time show that peak concentration occurs at later times with increasing depth, and that maximum concentration decreases with depth. These statistical analyses support the conclusions from the original investigation.  相似文献   

Reports     

William W. Dressler  Stephen B. Bush  Ben Wisner  Dennis DiPietre 《GeoJournal》1990,22(1):116-120

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Physical properties of asteroid 433 Eros     

Ben Zellner 《Icarus》1976,28(1):149-153

Newly available photometric, polarimetric, spectroscopic, thermal-radiometric, radar, and occultation results are synthesized in order to derive a coherent model for Eros. The geometric albedo is 0.19±0.01 at the visual wavelength, and the overall dimensions are approximately 13 × 15 × 36km. The rotation is about the short axis, in the direct sense, with a sidereal period of 5^h16^m13^s.4. The pole of rotation lies within a few degrees of ecliptic coordinates λ = 16° and β = + 11°.Eros is uniformly coated with a particulate surface layer several millimeters thick. It has an iron-bearing silicate composition, similar to that of a minority of main-belt asteroids, and probably identifiable with H-type ordinary chondrites.  相似文献   

Crystal fractionation in the friction melts of seismic faults (Alpine Fault, New Zealand)     

Laurence N. Warr  Ben A. van der Pluijm 《Tectonophysics》2005,402(1-4):111

Compositional variations are documented in friction melts along the Hari Hari section of the Alpine Fault, New Zealand, with multiple stages of melt injection into quartzo-feldspathic schists. Intermediate to felsic melts were heterogeneous in composition, but all fractions show a common trend, with a tendency for the younger melt layers and glasses to be more alkali − (Na + K) and Si-enriched, while being depleted in mafic (Fe + Mg + Mn) components. These changes are attributed primarily to crystal fractionation of the melt during transport. Farther traveled molten layers were on the whole less viscous, mostly due to a higher melt-to-clast ratio; however, compositional change, together with a decrease in volatile content, produced a progressively more viscous liquid melt with time. The glass phase is interpreted as a remnant of this high viscosity felsic residual melt that was preserved during final quenching. Following initial failure, the formation of largely phyllosilicate-derived, volatile-rich, lower viscosity melt corresponds with a phase of fault weakening. Subsequent rapid crystal fractionation during melt transport, the loss of volatiles and freezing of residual melt contributed to the strengthening of the fault during seismic slip.  相似文献   

Erratum à l'article Mise en évidence et analyse d'une structure atlasique ennoyée au front de la Chaîne alpine tunisienne [C. R. Geoscience 336 (2004) 1293–1300]     

Sami Khomsi  Mourad Bédir  M. Ghazi Ben Jemia 《Comptes Rendus Geoscience》2005,337(5):547

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Thérèse Mound: a case study of coral bank development in the Belgica Mound Province,Porcupine Seabight     

Ben De Mol  Max Kozachenko  Andy Wheeler  Hugo Alvares  Jean-Pierre Henriet  Karine Olu-Le Roy 《International Journal of Earth Sciences》2007,96(1):103-120

High-resolution seismic profiles, swath bathymetry, side-scan sonar data and video imageries are analysed in this detailed study of five carbonate mounds from the Belgica mound province with special emphasis on the well-surveyed Thérèse Mound. The selected mounds are located in the deepest part of the Belgica mound province at water depths of 950 m. Seismic data illustrate that the underlying geology is characterised by drift sedimentation in a general northerly flowing current regime. Sigmoidal sediment bodies create local slope breaks on the most recent local erosional surface, which act as the mound base. No preferential mound substratum is observed, neither is there any indication for deep geological controls on coral bank development. Seismic evidence suggests that the start-up of the coral bank development was shortly after a major erosional event of Late Pliocene–Quaternary age. The coral bank geometry has been clearly affected by the local topography of this erosional base and the prevailing current regime. The summits of the coral banks are relatively flat and the flanks are steepest on their upper slopes. Deposition of the encased drift sequence has been influenced by the coral bank topography. Sediment waves are formed besides the coral banks and are the most pronounced bedforms. These seabed structures are probably induced by bottom current up to 1 m/s. Large sediment waves are colonised by living corals and might represent the initial phase of coral bank development. The biological facies distribution of the coral banks illustrate a living coral cap on the summit and upper slope and a decline of living coral populations toward the lower flanks. The data suggest that the development of the coral banks in this area is clearly an interaction between biological growth processes and drift deposition both influenced by the local topography and current regime.  相似文献