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11.
This work includes a study of some properties such as speed, apparent width, acceleration and latitudes, etc. of all types of Prominence Eruptions (PEs) and the associated Coronal Mass Ejections (CMEs) observed during the period of 1997–2006 by Nobeyama Radioheliograph (NORH) and SOHO/LASCO covering the solar cycle 23. The average speed of prominences and associated CMEs are 51 km/sec and 559 km/sec, respectively. The average angular width is 32° and 74°, respectively. As expected the associated CMEs are relatively faster and wider than the prominences. 相似文献
12.
Operational activities in the ocean like planning for structural repairs or fishing expeditions require real time prediction of waves over typical time duration of say a few hours. Such predictions can be made by using a numerical model or a time series model employing continuously recorded waves. This paper presents another option to do so and it is based on a different time series approach in which the input is in the form of preceding wind speed and wind direction observations. This would be useful for those stations where the costly wave buoys are not deployed and instead only meteorological buoys measuring wind are moored. The technique employs alternative artificial intelligence approaches of an artificial neural network (ANN), genetic programming (GP) and model tree (MT) to carry out the time series modeling of wind to obtain waves. Wind observations at four offshore sites along the east coast of India were used. For calibration purpose the wave data was generated using a numerical model. The predicted waves obtained using the proposed time series models when compared with the numerically generated waves showed good resemblance in terms of the selected error criteria. Large differences across the chosen techniques of ANN, GP, MT were not noticed. Wave hindcasting at the same time step and the predictions over shorter lead times were better than the predictions over longer lead times. The proposed method is a cost effective and convenient option when a site-specific information is desired. 相似文献
13.
Mafic alkalic magmatism in central Kachchh,India: a monogenetic volcanic field in the northwestern Deccan Traps 总被引：1，自引：0，他引：1
Magmatism in Kachchh, in the northwestern Deccan continental flood basalt province, is represented not only by typical tholeiitic
flows and dikes, but also plug-like bodies, in Mesozoic sandstone, of alkali basalt, basanite, melanephelinite and nephelinite,
containing mantle nodules. They form the base of the local Deccan stratigraphy and their volcanological context was poorly
understood. Based on new and published field, petrographic and geochemical data, we identify this suite as an eroded monogenetic
volcanic field. The plugs are shallow-level intrusions (necks, sills, dikes, sheets, laccoliths); one of them is known to
have fed a lava flow. We have found local peperites reflecting mingling between magmas and soft sediment, and the remains
of a pyroclastic vent composed of non-bedded lapilli tuff breccia, injected by mafic alkalic dikes. The lapilli tuff matrix
contains basaltic fragments, glass shards, and detrital quartz and microcline, with secondary zeolites, and there are abundant
lithic blocks of mafic alkalic rocks. We interpret this deposit as a maar-diatreme, formed due to phreatomagmatic explosions
and associated wall rock fragmentation and collapse. This is one of few known hydrovolcanic vents in the Deccan Traps. The
central Kachchh monogenetic volcanic field has >30 individual structures exposed over an area of ∼1,800 km2 and possibly many more if compositionally identical igneous intrusions in northern Kachchh are proven by future dating work
to be contemporaneous. The central Kachchh monogenetic volcanic field implies low-degree mantle melting and limited, periodic
magma supply. Regional directed extension was absent or at best insignificant during its formation, in contrast to the contemporaneous
significant directed extension and vigorous mantle melting under the main area of the Deccan flood basalts. The central Kachchh
field demonstrates regional-scale volcanological, compositional, and tectonic variability within flood basalt provinces, and
adds the Deccan Traps to the list of such provinces containing monogenetic- and/or hydrovolcanism, namely the Karoo-Ferrar
and Emeishan flood basalts, and plateau basalts in Saudi Arabia, Libya, and Patagonia. 相似文献
14.
Pooja?V.?Kshirsagar Hetu?C.?ShethEmail author Sheila?J.?Seaman Badrealam?Shaikh Poonam?Mohite Trupti?Gurav D.?Chandrasekharam 《Bulletin of Volcanology》2012,74(2):559-577
Spherulites and thundereggs are rounded, typically spherical, polycrystalline objects found in glassy silicic rocks. Spherulites
are dominantly made up of radiating microscopic fibers of alkali feldspar and a silica mineral (commonly quartz). They form
due to heterogeneous nucleation in highly supercooled rhyolitic melts or by devitrification of glass. Associated features
are lithophysae (“stone bubbles”), which have an exterior (sometimes concentric shells) of fine quartz and feldspar, and internal
cavities left by escaping gas; when filled by secondary silica, these are termed thundereggs. Here, we describe four distinct
occurrences of spherulites and thundereggs, in pitchstones (mostly rhyolitic, some trachytic) of the Deccan Traps, India.
The thundereggs at one locality were previously misidentified as rhyolitic lava bombs and products of pyroclastic extrusive
activity. We have characterized the thundereggs petrographically and geochemically and have determined low contents of magmatic
water (0.21–0.38 wt.%) in them using Fourier transform infrared spectroscopy. We consider that the spherulite-bearing outcrops
at one of the localities are of lava flows, but the other three represent subvolcanic intrusions. Based on the structural
disposition of the Deccan sheet intrusions studied here and considerations of regional geology, we suggest that they are cone
sheets emplaced from a plutonic center now submerged beneath the Arabian Sea. 相似文献
15.
F. H. Grover 《Geophysical Journal International》1971,26(1-4):41-52
Summary Brief outlines are given of the problem of identifying low frequency acoustic waves from atmospheric background noise and of the methods used by UKAEA to improve detection of these waves.
An important aspect of the experimental work has been to develop devices to reduce atmospheric pressure noise, suitable for use at existing microbarograph recording sites, and to evaluate their performance in field tests. Some interim results from these experiments are given. 相似文献
An important aspect of the experimental work has been to develop devices to reduce atmospheric pressure noise, suitable for use at existing microbarograph recording sites, and to evaluate their performance in field tests. Some interim results from these experiments are given. 相似文献
16.
Paula M. Davidson John Grover Donald H. Lindsley 《Contributions to Mineralogy and Petrology》1982,80(1):88-102
Experiments at high pressure and temperature indicate that excess Ca may be dissolved in diopside. If the (Ca, Mg)2Si2O6 clinopyroxene solution extends to more Ca-rich compositions than CaMgSi2O6, macroscopic regular solution models cannot strictly be applied to this system. A nonconvergent site-disorder model, such as that proposed by Thompson (1969, 1970), may be more appropriate. We have modified Thompson's model to include asymmetric excess parameters and have used a linear least-squares technique to fit the available experimental data for Ca-Mg orthopyroxene-clinopyroxene equilibria and Fe-free pigeonite stability to this model. The model expressions for equilibrium conditions \(\mu _{{\text{Mg}}_{\text{2}} {\text{Si}}_{\text{2}} {\text{O}}_{\text{6}} }^{{\text{opx}}} = \mu _{{\text{Mg}}_{\text{2}} {\text{Si}}_{\text{2}} {\text{O}}_{\text{6}} }^{{\text{cpx}}} \) (reaction A) and \(\mu _{{\text{Ca}}_{\text{2}} {\text{Si}}_{\text{2}} {\text{O}}_{\text{6}} }^{{\text{opx}}} = \mu _{{\text{Ca}}_{\text{2}} {\text{Si}}_{\text{2}} {\text{O}}_{\text{6}} }^{{\text{cpx}}} \) (reaction B) are given by: 1 $$\begin{gathered} \Delta \mu _{\text{A}}^{\text{O}} = {\text{RT 1n}}\left[ {\frac{{(X_{{\text{Mg}}}^{{\text{opx}}} )^2 }}{{X_{{\text{Mg}}}^{{\text{M1}}} \cdot X_{{\text{Mg}}}^{{\text{M2}}} }}} \right] - \frac{1}{2}\{ W_{21} [2(X_{{\text{Ca}}}^{{\text{M2}}} )^3 - (X_{{\text{Ca}}}^{{\text{M2}}} ] \hfill \\ {\text{ + 2W}}_{{\text{22}}} [X_{{\text{Ca}}}^{{\text{M2}}} )^2 - (X_{{\text{Ca}}}^{{\text{M2}}} )^3 + \Delta {\text{G}}_{\text{*}}^{\text{0}} (X_{{\text{Ca}}}^{{\text{M1}}} \cdot X_{{\text{Ca}}}^{{\text{M2}}} )\} \hfill \\ {\text{ + W}}^{{\text{opx}}} (X_{{\text{Wo}}}^{{\text{opx}}} )^2 \hfill \\ \Delta \mu _{\text{B}}^{\text{O}} = {\text{RT 1n}}\left[ {\frac{{(X_{{\text{Ca}}}^{{\text{opx}}} )^2 }}{{X_{{\text{Ca}}}^{{\text{M1}}} \cdot X_{{\text{Ca}}}^{{\text{M2}}} }}} \right] - \frac{1}{2}\{ 2W_{21} [2(X_{{\text{Mg}}}^{{\text{M2}}} )^2 - (X_{{\text{Mg}}}^{{\text{M2}}} )^3 ] \hfill \\ {\text{ + W}}_{{\text{22}}} [2(X_{{\text{Mg}}}^{{\text{M2}}} )^3 - (X_{{\text{Mg}}}^{{\text{M2}}} )^2 + \Delta {\text{G}}_{\text{*}}^{\text{0}} (X_{{\text{Mg}}}^{{\text{M1}}} \cdot X_{{\text{Mg}}}^{{\text{M2}}} )\} \hfill \\ {\text{ + W}}^{{\text{opx}}} (X_{{\text{En}}}^{{\text{opx}}} )^2 \hfill \\ \hfill \\ \end{gathered} $$ where 1 $$\begin{gathered} \Delta \mu _{\text{A}}^{\text{O}} = 2.953 + 0.0602{\text{P}} - 0.00179{\text{T}} \hfill \\ \Delta \mu _{\text{B}}^{\text{O}} = 24.64 + 0.958{\text{P}} - (0.0286){\text{T}} \hfill \\ {\text{W}}_{{\text{21}}} = 47.12 + 0.273{\text{P}} \hfill \\ {\text{W}}_{{\text{22}}} = 66.11 + ( - 0.249){\text{P}} \hfill \\ {\text{W}}^{{\text{opx}}} = 40 \hfill \\ \Delta {\text{G}}_*^0 = 155{\text{ (all values are in kJ/gfw)}}{\text{.}} \hfill \\ \end{gathered} $$ . Site occupancies in clinopyroxene were determined from the internal equilibrium condition 1 $$\begin{gathered} \Delta G_{\text{E}}^{\text{O}} = - {\text{RT 1n}}\left[ {\frac{{X_{{\text{Ca}}}^{{\text{M1}}} \cdot X_{{\text{Mg}}}^{{\text{M2}}} }}{{X_{{\text{Ca}}}^{{\text{M2}}} \cdot X_{{\text{Mg}}}^{{\text{M1}}} }}} \right] + \tfrac{1}{2}[(2{\text{W}}_{{\text{21}}} - {\text{W}}_{{\text{22}}} )(2{\text{X}}_{{\text{Ca}}}^{{\text{M2}}} - 1) \hfill \\ {\text{ + }}\Delta G_*^0 (X_{{\text{Ca}}}^{{\text{M1}}} - X_{{\text{Ca}}}^{{\text{M2}}} ) + \tfrac{3}{2}(2{\text{W}}_{{\text{21}}} - {\text{W}}_{{\text{22}}} ) \hfill \\ {\text{ (1}} - 2X_{{\text{Ca}}}^{{\text{M1}}} )(X_{{\text{Ca}}}^{{\text{M1}}} + \tfrac{1}{2})] \hfill \\ \end{gathered} $$ where δG E 0 =153+0.023T+1.2P. The predicted concentrations of Ca on the clinopyroxene Ml site are low enough to be compatible with crystallographic studies. Temperatures calculated from the model for coexisting ortho- and clinopyroxene pairs fit the experimental data to within 10° in most cases; the worst discrepancy is 30°. Phase relations for clinopyroxene, orthopyroxene and pigeonite are successfully described by this model at temperatures up to 1,600° C and pressures from 0.001 to 40 kbar. Predicted enthalpies of solution agree well with the calorimetric measurements of Newton et al. (1979). The nonconvergent site disorder model affords good approximations to both the free energy and enthalpy of clinopyroxenes, and, therefore, the configurational entropy as well. This approach may provide an example for Febearing pyroxenes in which cation site exchange has an even more profound effect on the thermodynamic properties. 相似文献
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19.
Sam Fankhauser Alex Bowen Raphael Calel Antoine Dechezleprêtre David Grover James Rydge Misato Sato 《Global Environmental Change》2013,23(5):902-913
As the world considers greener forms of economic growth, countries and sectors are beginning to position themselves for the emerging green economy. This paper combines patent data with international trade and output data in order to investigate who the winners of this “green race” might be. The analysis covers 110 manufacturing sectors in eight countries (China, Germany, France, Italy, Japan, South Korea, UK and the US) using date for the period 2005–2007. We identify three success factors for green competitiveness at the sector level: the speed at which sectors convert to green products and processes (measured by green innovation), their ability to gain and maintain market share (measured by existing comparative advantages) and a favourable starting point (measured by current output). We find that the green race is likely to alter the present competitiveness landscape. Many incumbent country-sectors with strong comparative advantages today lag behind in terms of green conversion, suggesting that they could lose their competitive edge. Japan, and to a lesser extent Germany, appear best placed to benefit from the green economy, while other European countries (Italy in particular) could fall behind. However, the green economy is much broader than the few flagship sectors on which the debate tends to focus, and each country has its niches of green competitiveness. 相似文献
20.
Triple Differencing with Kalman Filtering: Making It Work 总被引：4，自引：0，他引：4
Since global positioning system (GPS) measurements are ranges (code) and biased ranges (carrier), it seems natural to model
them as ranges and determine the biases. This is particularly compelling since the double-difference range biases turn out
to be integers. At some level there is also an elegance, perhaps therefore a naturalness, to modeling the carrier measurements
as time differences of double differences. While something is lost something else is gained. Here we apply the proven delayed-state
Kalman filter to processing carrier phase measurements as triple differences. In practice we process these triple differences
along with double-difference code measurements. We also treat the measurement error as, mostly, Gauss-Markov states to be
determined. Many of the details are discussed and experimental results are included. These demonstrate that excellent performance
can be obtained if the Kalman filter modeling is done carefully. ? 2000 John Wiley & Sons, Inc. 相似文献