EXPERIMENTAL STUDY ON BED SHEAR STRESS AND SEDIMENT TRANSPORT IN A MEANDERING LABORATORY CHANNEL     

L. YILMAZ  Vijay P. SINGH  S.K. MISHRA  D. D. ADRIAN  J. J. SANSALONE Civil Engineering Faculty  Hydraulic Division  Technical University of Istanbul    Maslak  Istanbul  Turkey 《国际泥沙研究》2002,17(1)

1 INTRODUCTION River erosion is a complex phenomenon. The rate of bank retreat is determined by flow, bed topography, sediment transport, bank properties, and water quality. Prediction of future river planform changes and the knowledge of river erosion and river meandering are required for land use planning in alluvial river valleys and determining locations for bridges and hydraulic structures. The control of riverbank erosion requires prediction of flow and bed features in a meanderin…  相似文献   

Horizontal moisture distribution from TIROS-N high resolution infrared sounder (HIRS)     

Vijay K. Agarwal  Ashajayanthi Loganathan 《Journal of Earth System Science》1981,90(3):291-304

A direct linear relationship between water vapour content of lower, middle and upper-middle troposphere respectively with the radiances for 8.3, 7.3 and 6.7 μm spectral observations has been attempted. From the atmospheric simulations such a relationship is found to exist with a good degree of correlation and is seen to be quite insensitive to temperature changes. Such an approach is used to interpret the water vapour imageries obtained from TIROS-N sounder through construction of detailed water vapour distribution maps.  相似文献   

Fatigue life of critical members in a railway truss bridge     

Vijay K. Garg  Kuang-Han Chu  A. Wiriyachai 《地震工程与结构动力学》1982,10(6):779-795

The fatigue life of critical members, such as hangers, floor-beams and stringers in a single track, open deck railroad truss bridge, was investigated for various unit freight trains, operating at different speeds. A partial bridge model was used, along with a three-car train, to determine the stress cycles. For determining the fatigue lives of critical members, four fully-loaded trains per day were assumed to pass over the bridge. Each train was assumed to consist of one hundred 70-ton cars or seventy 100-ton cars. The 100-ton freight cars cause large stress ranges, and consequently shorter fatigue lives than the 70-ton freight cars. For the hundred-car train, with 70-ton and 100-ton cars mixed in various proportions, the fatigue lives became shorter as the percentage of 100-ton cars in the consist was increased. The impact percentages were also studied.  相似文献   

Galactic evolution and star counts in the milky way     

Annie C. Robin  Michel Crézé  Vijay Mohan 《Astrophysics and Space Science》1989,156(1-2):9-18

A model of population synthesis for our Galaxy is used to estimate the constraints imposed by photometric and astrometric star counts. We construct a statistical method to compute the degree of compatibility of the model with the data in the form of a multidimensional functionf(V, B-V, U-B, ). We apply the method to the determination of the star formation history in the Galaxy from Schmidt plates towards the anticentre. Although the presently available data do not allow us to draw firm conclusions, we show that the same kind of data with a slightly better photometric accuracy and with proper motions would give new constraints on the past star formation rate of the Galaxy.  相似文献   

Spatiotemporal variations of temperature and precipitation extremes in the Poyang Lake basin,China   总被引：1，自引：0，他引：1  

Qiang Zhang  Mingzhong Xiao  Vijay P. Singh  Yeqiao Wang 《Theoretical and Applied Climatology》2016,124(3-4):855-864

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Spatiotemporal properties of growing season indices during 1961–2010 and possible association with agroclimatological regionalization of dominant crops in Xinjiang,China     

Hui Ci  Qiang Zhang  Vijay P. Singh  Mingzhong Xiao  Lin Liu 《Meteorology and Atmospheric Physics》2016,128(4):513-524

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Distribution and geochemistry of selected trace elements in the lignites of Cambay basin,Gujarat, western India     

P. K. Singh  Vijay Kumar Singh  Pramod Kumar Rajak  M. P. Singh  A. S. Naik 《Journal of the Geological Society of India》2016,88(2):131-146

In the present investigation all the working lignite seams of Cambay basin of Gujarat have been studied to see the distribution and geochemistry of selected major/minor elements like Fe, Ca, Na, K, Mg, and Mn and trace elements like Cu, Co, Cr, Cd, Ni, Pb and Zn. The vertical variation of these elements along the seam profiles has been studied to see the pattern of distribution of these elements and also to know the horizons of their enrichment and the probable cause. Further, these elements have been correlated among themselves and also with organic and inorganic matter of lignite. The correlation study indicates that in Tadkeshwar upper seam Fe has its affinity with huminite while Mg and Na have their affinity with liptinite and in Tadkeshwar lower seam Na has an affinity with liptinite. In Vastan upper seam Mn and Cu are associated with inertinite and Na with huminite while in Vastan lower seam Cu relates to huminite and Cd to liptinite and huminite. In Rajpardi seam Ca and Co are associated with huminite. The study provides information on the mode of occurrence of elements of less studied lignites of western India.  相似文献   

Distribution and Origin of Seamounts in the Central Indian Ocean Basin     

Pranab Das  Sridhar D. Iyer  V. N. Kodagali  K. S. Krishna 《Marine Geodesy》2005,28(3):259-269

Approximately 200 seamounts of different dimensions have been identified, from multibeam bathymetry maps of the Central Indian Ocean Basin (CIOB) (9°S to 16°S and 72°E to 80°E), of which 61% form eight chains that trend N-S. The seamounts are clustered above and below 12°S latitude. Area II (9°-12°S) shows a concentration of smaller seamounts (≤400 m height), and area I (12°-15°S) has a mixed population (including both less and more than 400 m height). Inspite of the differences in their height, the seamounts of these eight chains are morphologically (slope angle, flatness, basal width) corelatable. Furthermore, we suggest that height-width ratio could be useful in identifying the style of seamount eruption. The seamount chains in the CIOB probably originated from propagative fractures and were produced between 61 and 52 Ma (chrons A26 to A23) as a result of the interaction between the conjugate crusts of the Central Indian and Southeast Indian Ridges during the Indo-Eurasian collision event.  相似文献   

Improved coastal boundary condition for surface water waves     

David R. Steward  Vijay G. Panchang 《Ocean Engineering》2001,28(1)

Surface water waves in coastal waters are commonly modeled using the mild slope equation. One of the parameters in the coastal boundary condition for this equation is the direction at which waves approach a coast. Three published methods of estimating this direction are examined, and it is demonstrated that the wave fields obtained using these estimates deviate significantly from the corresponding analytic solution. A new method of estimating the direction of approaching waves is presented and it is shown that this method correctly reproduces the analytic solution. The ability of these methods to simulate waves in a rectangular harbor is examined.  相似文献   

Analysis of multibeam-Hydrosweep echo peaks for seabed characterisation     

B. Chakraborty  H. Schenke  V. Kodagali  R. Hagen 《Geo-Marine Letters》2001,20(3):174-181

Echo-peak data of outer and normal incidence beams from five different Southern Ocean bottom topographic regions have been analysed. The Rice and Extremal probability density function (PDF) statistical approaches reveal that the seabed roughness is, in general, Gaussian in nature except in the case of the Kainan Maru seamount summit (area D). The outer beams of the Enderby abyssal plain (area C) echo-peak PDF statistics reveal the highest possible large-scale feature dominance. Interestingly, Extremal PDF fit parameters (!) from the Agulhas Basin (area A) show a less dominant large-scale roughness than in the case of area C. Large-scale feature dominance up to 15° beam angle is observed in the case of mixed roughness seabeds such as area B (southwest Indian ridge) and area E (Meteor Rise). No increase in the 30°-beam Extremal PDF parameters is observed in these areas. Maximum microtopographic roughness is documented in area D on the summit of Kainan Maru seamount. The estimated fit parameters using Extremal statistics of outer-beam peak data provide a better understanding of the scattering process. Previously determined power law and volume roughness parameters using composite roughness theory are given for the five different areas. These support the results obtained using Rice and Extremal PDFs. The existence of higher volume roughness parameters and power law parameters for medium-scale roughness, along with dominant microtopographic features, are evident from the results of this study.  相似文献