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11.
A study of the combined buoyancy effects of thermal and mass diffusion on MHD convection flow in the presence of Hall currents with variable suction and heat generation has been carried out. Analytical expressions for the velocity and the temperature of the fluid are given. The effects of Hall currents, parameterm, and heat source parameter on the velocity are discussed. 相似文献
12.
Bianchi type-II, VIII, and IX models have been investigated in scalar-tensor theories developed by Saez (1985), Saez and Ballester (1985), and Lau and Prokhovnik (1986) (under the assumption of a certain relationship between the cosmological term and the scalar field ). The dynamical behaviour of these models has been studied. 相似文献
13.
K. S. Rao Y. S. Rao H. K. Al Jassar 《Journal of the Indian Society of Remote Sensing》2008,36(2):123-136
Spaceborne Imaging Radar (SIR-C) data acquired over Gujarat, India in 1994 were processed and analysed using differnet techniques
applicable to polarimetric SAR data such as polarization signatures, polarization index, decomposition of the signal and polarization
phase difference and limited groundtruth data. It has been observed that multi-frequency polarimetric data enhances the potential
of retrieving geo-physical parameters. The polarization signatures are found to vary with the nature of the target. Target
decomposition of the returned signal will be useful for the classification of various features. Polarization Phase Difference
(PPD) gives good information about the vegetation parameters. 相似文献
14.
This paper introduces a new method for GPS signal acquisition, which is based on the repeatability of successive code phase
measurements and the M-of-N search algorithm. The performance of the proposed method in terms of probability of signal detection
is similar to that of traditional methods, except that the calculation of the probability of detection does not rely on the
noise distribution or the Carrier-to-Noise ratio (C/N0). The code phase repeatability-based method is presented along with equations for probability of detection and probability
of false detection. If the distribution of the noise is known, it also provides an estimate of the C/N0. The proposed method is illustrated for coherent and non-coherent acquisition and C/N0 estimation. 相似文献
15.
An important task in modern geostatistics is the assessment and quantification of resource and reserve uncertainty. This uncertainty
is valuable support information for many management decisions. Uncertainty at specific locations and uncertainty in the global
resource is of interest. There are many different methods to build models of uncertainty, including Kriging, Cokriging, and
Inverse Distance. Each method leads to different results. A method is proposed to combine local uncertainties predicted by
different models to obtain a combined measure of uncertainty that combines good features of each alternative. The new estimator
is the overlap of alternate conditional distributions. 相似文献
16.
Artificial neural network and liquefaction susceptibility assessment: a case study using the 2001 Bhuj earthquake data,Gujarat, India 总被引:2,自引:0,他引:2
D. Ramakrishnan T. N. Singh N. Purwar K. S. Barde Akshay. Gulati S. Gupta 《Computational Geosciences》2008,12(4):491-501
This study pertains to prediction of liquefaction susceptibility of unconsolidated sediments using artificial neural network
(ANN) as a prediction model. The backpropagation neural network was trained, tested, and validated with 23 datasets comprising
parameters such as cyclic resistance ratio (CRR), cyclic stress ratio (CSR), liquefaction severity index (LSI), and liquefaction
sensitivity index (LSeI). The network was also trained to predict the CRR values from LSI, LSeI, and CSR values. The predicted
results were comparable with the field data on CRR and liquefaction severity. Thus, this study indicates the potentiality
of the ANN technique in mapping the liquefaction susceptibility of the area. 相似文献
17.
Discrete chorus-type emission and whistler precursors recorded in March 1972 during day time hours at our ground based station Gulmarg are presented. It is shown that discrete chorus type emissions are generated in the equatorial region (L 1.2) during cyclotron resonance interaction between the propagating whistler wave and the gyrating electrons. The whistler precursors are explained in terms of the mechanism suggested by Dowden (1972). 相似文献
18.
An exact analysis of Hall current on hydromagnetic free convection with mass transfer in a conducting liquid past an infinite vertical porous plate in a rotating fluid has been presented. Exact solution for the velocity field has been obtained and the effects ofm (Hall parameter),E (Ekman number), andS
c (Schmidt number) on the velocity field have been discussed.Nomenclature
C
species concentration
-
C
w
concentration at the porous plate
-
C
species concentration at infinity
-
C
p
specific heat at constant pressure
-
D
chemical molecular diffusivity
-
g
acceleration due to gravity
-
E
Ekman number
-
G
Grashof number
-
H
0
applied magnetic field
-
j
x, jy, jz
components of the current densityJ
-
k
thermal conductivity
-
M
Hartman number
-
m
Hall parameter
-
P
Prandtl number
-
Q
heat flux per unit area
-
S
c
Sehmidt number
-
T
temperature of the fluid near the plate
-
T
w
temperature of the plate
-
T
temperature of the fluid in the free-stream
-
u, v, w
components of the velocity fieldq,
-
U
uniform free stream velocity
-
w
0
suction velocity
-
x, y, z
Cartesian coordinates
-
Z
dimensionless coordinate normal to the plate.
Greek symbols
coefficient of volume expansion
- *
coefficient of expansion with concentration
- e
cyclotron frequency
-
dimensionless temperature
- *
dimensionless concentration
-
v
kinematic viscosity
-
density of the fluid in the boundary layer
-
coefficient of viscosity
- e
magnetic permeability
-
angular velocity
-
electrical conductivity of the fluid
- e
electron collision time
- u
skin-friction in the direction ofu
- v
skin-friction in the direction ofv 相似文献
19.
In order to carry out a numerical study of the structure of rotationally distorted polytropes, the Monaghan and Roxburgh (1965) method is extended to include the second-order term in the perturbation parameter, . 相似文献
20.
A model of solar flare is proposed, taking into account the high temperature (109K) produced by the shock wave generated by the hydromagnetic wave at the junction of sunspot and the area just outside it and subsequent explosive hydrogen burning, producing the desired 1028–29 ergs of a solar flare. 相似文献