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In this paper, an attempt is made to study some interesting results of the coupled nonlinear equations in the at-mosphere. By introducing a phase angle function ξ, it is shown that the atmospheric equations in the presence of specific forcing exhibit the exact and explicit solitary wave solutions under certain conditions. 相似文献
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Shivhare Vikash Gupta Chanchal Mallick Javed Singh Chander Kumar 《Natural Hazards》2022,110(1):545-561
Natural Hazards - Geographical information system and remote sensing are proven to be an efficient tool for locating water harvesting and recharge structures, groundwater potential, runoff,... 相似文献
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This paper deals with a new family of coupled wave equations which are basically nonlinear in nature. An analyt-ical study enables us to show that these equations exhibit solitary wave profiles. Finally some remarks are drawn from the standpoint of atmospheric problem. 相似文献
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Selection of a set of dominant echo features to classify seafloor sediments using a multilayer perceptron neural network is
investigated at two acoustic frequencies (33 and 210 kHz). Several sets of inputs with different combinations of two, three,
four, five, and six echo features are exploited with three-layer neural networks. The performances of the networks are analyzed
to assess the most discriminating set of echo features for classification of seafloor sediments. The results of the overall
average performances reveal that backscatter strength and time spread are the two most important echo features at 33 kHz,
whereas backscatter strength has higher discriminating characteristics at 210 kHz for seafloor sediment classification. In
addition, a set of four echo features consisting of backscatter strength, time-spread, statistical skewness, and Hausdroff
dimension gives the highest success at both the acoustic frequencies. 相似文献
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Chanchal Sarbajna Sankar Bose V. Rajagopalan Kaushik Das Anjan Som A. K. Paul K. Shivkumar K. Umamaheswar Anjan Chaki 《Mineralogy and Petrology》2013,107(4):553-571
High Mg-Al granulite occurs as enclave within granite gneisses at Karimnagar, southern India, and it contains coarse granoblastic aggregates of orthopyroxene and sapphirine with minor amount of cordierite, spinel and phlogopite. An important chemical characteristic of these minerals is their extremely high MgO content and the high Cr2O3 in sapphirine and spinel. Textural analysis shows sapphirine + orthopyroxene + cordierite as the peak-metamorphic assemblage that possibly evolved though the breakdown of a spinel-bearing assemblage. Cation exchange geothermometers involving orthopyroxene, sapphirine and spinel yield temperatures of 600–800 °C with a maximum of 860 °C implying an event of high temperature (HT) metamorphism. Pseudosection analysis in the FeO–MgO–Al2O3–SiO2 chemical system shows the stability of the peak- assemblage below 6.2 kbar. Subsequently, the rock underwent hydration and cooling with the appearance of phlogopite in the assemblage. Chromium enrichment is possibly inherited from the protolith and its presence presumably stabilized sapphirine and spinel below their high-temperature stability field. The recorded Rb–Sr age of ca. 2,500 Ma in host granite gneiss marks the upper age limit of HT metamorphism. Presence of patchy, lobate grains as well as veinlets of uraninite and brannerite is also a characteristic feature of the rock. Uranium mineralization took place during the post peak metamorphic stage, sulfide mineralization represented by tiny grains and veinlets of pyrite, millerite and pentlandite coincided with, and outlasted the uranium mineralization. The U–Th–Pb chemical ages of uraninite grains suggest ca. 2,200?±?12 Ma for the age of uranium mineralization in the granulite. Based on the field relations, it is surmised that the granulite metamorphism in the study area is older than ca. 2,500 Ma and is comparable with an event in the other parts of Eastern Dharwar Craton. It can be conceived as a widespread event in southern India. 相似文献
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In the present investigation, Electron acoustic solitons in a plasma consisting of cold electrons, superthermal hot electrons and stationary ions are studied. The basic properties of small but finite amplitude solitary potential structures that may exist in a given plasma system have been investigated theoretically using reductive perturbation technique. It has been found that the profile of electron acoustic solitary wave structures is very sensitive to relative hot electron density, $\alpha(=\frac{n_{h0}}{n_{c0}})$ , temperature of hot to cold electrons, $\theta(=\frac{T_{h}}{T_{c}})$ and the spectral index κ. The implications of the present study may be applied to explain some features of large amplitude localized structures that may occur in the plasma sheet boundary layer. 相似文献
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The feasibility of an artificial neural network based approach is investigated to estimate the values of mean grain size of
seafloor sediments using four dominant echo features, extracted from acoustic backscatter data. The acoustic backscatter data
were collected using a dual-frequency (33 and 210 kHz) single-beam, normal-incidence echo sounder at twenty locations in the
central part of the western continental shelf of India. Statistically significant correlations are observed between the estimated
average values of mean grain size of sediments and the ground-truth data at both the frequencies. The results indicate that
once a multi-layer perceptron model is trained with back-propagation algorithm, the values of mean grain size can reasonably
be estimated in an experimental area. The study also revealed that the consistency among the estimated values of mean grain
size at different acoustic frequencies is considerably improved with the neural network based method as compared to that with
a model-based approach. 相似文献
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