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排序方式: 共有64条查询结果,搜索用时 15 毫秒
1.
A satellite port has been proposed about 14.8 km north of Madras port on the east coast of India. As the interference of a satellite port with the existing pattern of longshore sediment transport will generate coastal imbalance in the region, a numerical model study involving sediment transport and combined wave refraction-diffraction was conducted to predict the shoreline behaviour. A realistic approach to the study was made to meet the objectives by considering wave height-wave period distributions in the region and duration and sequence of their occurrence during major monsoon seasons. This method of analysis enabled us to predict: (i) the extent of general shoreline advancement, particularly in front of a tidal inlet—a source of the cooling water requirement for an existing thermal power plant; (ii) the extent of the coastal region that will be affected owing to recession of shoreline and its impact on: (a) the fishing community living along the coastal stretch; (b) the national highway running along the coast; and (c) the changes in nearshore bathymetry. Based on the studies, management plans were drawn to safeguard the coastal region from imbalances that will arise out of construction of the satellite port. This paper highlights the effects of a satellite port on the coastal region and the need for proper management. 相似文献
2.
J. S. Mani 《Natural Hazards》2004,31(2):523-536
Chennai coast, right from the inception of Madras harbourin the year 1876, has been experiencinghostile conditions such as (i) coastal erosion, (ii) sandbar formation at the entrance to inlets, (iii) sea water ingression and (iv) change insea bed elevation, etc. In addition, construction of a new satellite harbour, about18 km north of Madras harbour has produced a negative impact on the delicatecoastal features such as (i) Pulicat lake, (ii) Ennore shoals, etc. Construction ofthis satellite harbour has led to the accumulation of sand south of the southbreakwater of the harbour and its accelerated growth is of concern to an inletlocated 2.6~km south of the harbour. `Coastal erosion', a perennial problemassociated with north Chennai sea front for the past 100 years has been addressedin this paper. The paper discusses on a long term solution and details of themethodologies to be adopted for effective management of the coast. Thesolution presented in this paper is based on numerical model study consideringthe nearshore currents and wave induced sediment transports. 相似文献
3.
Distribution, use pattern and prospects for conservation of medicinal shrubs in Uttaranchal State, India 总被引:1,自引:0,他引:1
The present paper gives an insight into the distribution and use pattern of medicinal shrubs in Uttaranchal State. A total of 222 medicinal and aromatic shrub species have been appended based on secondary information. Euphorbiaceae, Rosaceae, Verbenaceae, and Fabaceae have the highest repre- sentatives of medicinal shrubs. Twenty one families had one species each in medicinal use. Verbenaceae and Euphorbiaceae in the sub-tropical region, Rosaceae in the temperate region, and Ericaceae and Rosaceae in the sub-alpine and alpine regions, respectively, had the highest representatives of medicinal shrubs. The distribution of medicinal shrubs was 42 % in sub-tropical, 29 % in warm temperate, 13 % in cool temperate, 9 % in sub-alpine and 7 % in the alpine region. Of the total species, 70 medicinal shrubs were native to the Himalayas and 22 native to Himalayan region including other Hima- layan countries. The most frequently used plant parts for various ailments were leaves (31 %) and roots (23 %). Most shrubs are being used for the diseases, viz. skin diseases, dysentery, cough, fever, wounds, and rheumatism. The present paper will help in the execution of strategies for promotion and cultivation of medicinal shrubs in Uttaranchal State. 相似文献
4.
V. R. S. Mani 《Journal of the Geological Society of India》2018,91(5):541-546
With the availability of multi sensor data in many fields, such as remote sensing, medical imaging or machine vision, sensor fusion has emerged as a new and promising research area. It is possible to have several images of the same scene providing different information although the scene is the same. This is because each image has been captured with a different sensor. A non-negative matrix factorization (NNMF) un mixing based fusion technique with vertex component analysis (VCA) based end member initialization and simple multiplicative update to improve the spatial resolution and to preserve the spectral resolution of the hyper spectral image is proposed. Its performance is analyzed with different number of iterations and end member initializations. A Constrained Non Negative Matrix Factorization unmixing based fusion technique is developed by adding a regularization term to the objective function to preserve the spectral resolution of the hyper spectral image, and its performance is analyzed with different number of iterations and end members. A rank two NNMF and hierarchical clustering based end member initialization and block principal pivoting algorithm based abundance estimation technique, for fusing hyper spectral image and simulated multispectral image is proposed and its performance is analyzed for different overlapping and non overlapping group of multispectral and hyper spectral bands. The performance of the above three methods are compared and analyzed. The obtained results show that the performance of rank two NNMF hierarchical clustering based fusion technique is better than the other two constrained and unconstrained NNMF un mixing based techniques. Also, the performance of these three proposed multi sensor image fusion techniques are compared with an existing image fusion technique. 相似文献
5.
Electromagnetic radiation, in its passage through the atmosphere, is attenuated by absorption and scattering by atmospheric
gases, dust and aerosols. The most important absorber is water vapour and the most significant parameter in atmospheric absorption
studies is the total precipitable water in the atmosphere. The present paper summarises the results of a study made to compute
the total precipitable water in the atmosphere over India using radiosonde and other data, as part of a programme for the
computation of direct, global and diffuse solar radiation at the ground from the solar constant. Using values of air temperature
and dew point from the ground up to 250 mb at 19 radiosonde stations and surface water vapour mixing ratio values at 105 surface
observatories in India, precipitable water amounts have been computed for 124 stations, for each month and for the whole year.
The paper describes the techniques used to extend the total precipitable water amounts derived from radiosonde data at 19
stations to 124 stations covering the major climatic zones in the country and presents the results in the form of 12 maps
showing the spatial and temporal distribution of total precipitable water over India 相似文献
6.
The vertical profiles of ozone and temperature from a series of balloon soundings at Delhi (28°N), Poona (18°N) and Trivandrum (8°N) were studied with synoptic meteorological data. While both ozone and temperature profiles show similar variations over all three stations, ozone maxima being always associated with thermally stable layers, the variations are most pronounced over Delhi, particularly in winter and in early spring when a series of western disturbances pass over north India. Both ozone and temperature profiles over Delhi show a layer structure characterized by a series of maxima and minima in both the vertical distribution of ozone and temperature and these are most pronounced in the lower stratosphere. These variations are associated with the influx of ozone-rich middle latitude stratospheric air over Delhi replacing subtropical air. 相似文献
7.
Anna Mani C. R. Sreedharan B. B. Huddar Y. Ramanathan 《Pure and Applied Geophysics》1972,100(1):101-108
Summary Results of measurements of the atmospheric electrical conductivity and potential gradient made during the sixth Scientific Cruise of the Indian Oceanographic Ship INS Kistna in the Bay of Bengal during February–March 1963 are presented. Observations were made when the skies were generally clear and the sea calm, in the geographical area 8°N to 17°N and 80°E to 95°E, on the outward journey of INS Kistna from Madras (80°E, 13°N) to Port Blair (93°E, 12°N) and on the return journey to Madras.Over the ocean where there are no local sources of pollution, the measured values of conductivity and potential gradient are in agreement with theoretical values, assuming that an ion equilibrium exists, that ions are destroyed primarily by collision with small ions of opposite sign and that small ions are produced only by cosmic radiation. The values of electrical conductivity obtained are generally of the same order as those to be expected from theoretical considerations and in general agreement with those obtained during the Carnegie cruises in the Indian Ocean in 1920. There are, however, significant variations near the coast where the electric structure above the ocean is affected by continental sources of pollution. Conductivity values near the land are about half that in the unpolluted air over the ocean but prevailing winds prevent the extension of pollution beyond 100–200 km from the coast in this season.
Zusammenfassung Es wird über Messungen der luftelektrischen Leitfähigkeit und des Potentialgefälles berichtet, welche während der Sechsten Wissenschaftlichen Kreuzfahrt des indischen Ozeanographischen Forschungsschiffes Ins Kistna in der Bengalischen Bucht im Februar und März 1963 ausgeführt wurden. Die Beobachtungen sind im allgemeinen bei klarem Himmel und ruhiger See gemacht worden, und zwar in dem geographischen Bereich zwischen 8 und 17°N und 80 und 95°E während der Ausfahrt der INS Kistna von Madras (80°E, 13°N) nach Port Blair (93°E, 12°N) und auf der Rückreise nach Madras. In den Bereichen des Ozeans, in denen keine örtlichen Pollutionsquellen bestehen, stimmen die gemessenen Werte der Leitfähigkeit und des Potentialgefälles mit den theoretischen Werten überein, die man erhält, wenn man annimmt, dass ein Ionengleichgewicht besteht, dass die schnellen Ionen vorwiegend durch Zusammenstoss mit schnellen Ionen des entgegengesetzten Vorzeichens vernichtet werden, und dass die schnellen Ionen nur durch die kosmische Höhenstrahlung erzeugt werden. Die Werte der Leitfähigkeit stimmen mit denen überein, die man aus theoretischen Überlegungen gewinnt, und auch mit denen, die während der Kreuzfahrten des Forschungsschiffes Carnegie im Indischen Ozean im Jahre 1920 gemessen Küste sind jedoch bedeutsame Abweichungen festzustellen, wo die elektrischen Verhältenisse über dem Ozean durch Pollutionsquellen auf dem Lande beeinflusst werden. Die Leitfähigkeitswerte nahe dem Land sind nur ungefähr halb so gross wie die in der pollutionsfreien Luft des offenen Ozeans-jedoch haben die während der Mess-Jahreszeit vorherrschenden Winde eine Ausbreitung der Pollutionszone auf einen Bereich von 100 bis 200 km von der Küste beschränkt.相似文献
8.
Devleena Mani T. Satish Kumar M. A. Rasheed D. J. Patil A. M. Dayal T. Gnaneshwar Rao V. Balaram 《Natural Resources Research》2011,20(1):75-88
The association of iodine with organic matter in sedimentary basins is well documented. High iodine concentration in soils
overlying oil and gas fields and areas with hydrocarbon microseepage has been observed and used as a geochemical exploratory
tool for hydrocarbons in a few studies. In this study, we measure iodine concentration in soil samples collected from parts
of Deccan Syneclise in the west central India to investigate its potential application as a geochemical indicator for hydrocarbons.
The Deccan Syneclise consists of rifted depositional sites with Gondwana–Mesozoic sediments up to 3.5 km concealed under the
Deccan Traps and is considered prospective for hydrocarbons. The concentration of iodine in soil samples is determined using
ICP-MS and the values range between 1.1 and 19.3 ppm. High iodine values are characteristic of the northern part of the sampled
region. The total organic carbon (TOC) content of the soil samples range between 0.1 and 1.3%. The TOC correlates poorly with
the soil iodine (r
2 < 1), indicating a lack of association of iodine with the surficial organic matter and the possibility of interaction between
the seeping hydrocarbons and soil iodine. Further, the distribution pattern of iodine compares well with two surface geochemical
indicators: the adsorbed light gaseous hydrocarbons (methane through butane) and the propane-oxidizing bacterial populations
in the soil. The integration of geochemical observations show the occurrence of elevated values in the northern part of the
study area, which is also coincident with the presence of exposed dyke swarms that probably serve as conduits for hydrocarbon
microseepage. The corroboration of iodine with existing geological, geophysical, and geochemical data suggests its efficacy
as one of the potential tool in surface geochemical exploration of hydrocarbons. Our study supports Deccan Syneclise to be
promising in terms of its hydrocarbon prospects. 相似文献
9.
The use of unconditionally stable implicit time integration techniques for pseudodynamic tests has been recently proposed and advanced by several researchers. Inspired by such developments, a pseudodynamic test scheme based on an unconditionally stable implicit time integration algorithm and dual displacement control is presented in this paper. The accuracy of the proposed scheme is proved with error-propagation analysis. It is shown by numerical examples and verification tests that the error-correction method incorporated can eliminate the spurious higher-mode response, which can often be excited by experimental errors. The practicality of the proposed scheme lies in the fact that the implementation is as easy as that of explicit schemes and that the convergence criteria required are compatible with the accuracy limits of ordinary test apparatus. 相似文献
10.
Numerical prediction of performance of submerged breakwaters 总被引:1,自引:0,他引:1
The results of a numerical model study on the transmission characteristics of a submerged breakwater are presented. Study aimed to determine the effect of depth of submergence, crest width, initial wave conditions and material properties on the transmission characteristics of the submerged breakwater. The results highlight the optimum crest width of the breakwater and optimum clear spacing between two breakwaters. A submerged permeable breakwater with ds/d=0.5, p=0.3 and f=1.0, reduces the transmission coefficient by about 10% than the impermeable breakwater. The results indicates an optimum width ratio of B/d=0.75 for achieving minimum transmission. By restricting the effective width ratio of the series of breakwaters to 0.75, studies were conducted to determine the effect of clear spacing between breakwaters on transmission coefficient, suggesting an optimum clear spacing of w/b=2.00 to obtain Kt below 0.6. 相似文献