A variational formalism for tidal excitation: non-rotating, homentropic stars     

Yasser Rathore    Avery E. Broderick  Roger Blandford 《Monthly notices of the Royal Astronomical Society》2003,339(1):25-32

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Classification of Polarimetric SAR Data Based on Object-Based Multiple Classifiers for Urban Land-Cover   总被引：1，自引：0，他引：1  

Masoud Habibi  Mahmod Reza Sahebi  Yasser Maghsoudi  Shaheen Ghayourmanesh 《Journal of the Indian Society of Remote Sensing》2016,44(6):855-863

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P- and S-wave anisotropy of a synthetic sandstone with controlled crack geometryl1     

J.S. Rathore  E. Fjaer  R.M. Holt  L. Renlie 《Geophysical Prospecting》1995,43(6):711-728

A method is reported for the production of synthetic porous sandstones containing cracks of known dimensions and geometry with respect to the matrix. A synthetic sandstone was manufactured from Sand cemented with an epoxy glue. The cracks of known geometry were introduced into the material in the manufacturing stage, by emplacing thin metallic discs in the Sand-epoxy matrix. These discs were chemically leached out of the consolidated porous sandstone. Acoustic anisotropy. and shear-wave splitting were observed in the synthetic sandstones. For the dry sample the observed angular dependence of the P- and S- wave velocities (at 100 kHz) compares well, qualitatively, with the theoretical models of Hudson and of Thomsen. Quantitatively, however, the experimental data fits Hudson's model better. For the case of a saturated sample the experimental results are in excellent agreement with Thomsen's model. Hudson's model, on the other hand, predicts a different angular dependence for P-waves. This demonstrates that the concept of fluid transfer between cracks and the ambient porosity can be a significant process. The results reported here are from the first successful experiment in which the theoretical models were tested on a porous material containing a known crack geometry.  相似文献   

Study of ductile shear zones (Galicia, Spain) using texture goniometry and magnetic fabric methods   总被引：1，自引：0，他引：1  

J.S. Rathore  G. Courrioux  P. Choukroune 《Tectonophysics》1983,98(1-2)

A joint magnetic and mica fabric study has been carried out on rocks from recognised shear zones in Galicia (Spain). The two main aims of the study are to determine strain gradients in a foliated material without any significant strain markers and to obtain a quantitative relationship between the magnetic susceptibility anisotropy ellipsoid and the mica fabric axes. The intensity parameters of the fabric on profiles intersecting the studied areas indicate the dominant influence of two major shear zones on the fabric development. The regional fabric shows less significant variations across minor (less developed) shear zones.The empirical relationship between magnetic fabric and strain reported by Rathore (1979, 1980) and Rathore and Henry (1982) is found to hold in the magnetic and mica fabrics comparison. The relationship found in this study is:  相似文献   

Controlled Fracture Growth by Blasting While Protecting Damages to Remaining Rock     

S. S. Rathore  S. Bhandari 《Rock Mechanics and Rock Engineering》2007,40(3):317-326

Summary. Conventional blasting causes cracks and fractures in the rock. Controlled blasting techniques produce the macrocrack in a desired direction and eliminate microcrack in the remaining rock. Macrocrack development in desired direction is required for extraction of dimensional stone and at the same time there is need to reduce microcrack development in the block and remaining rock. To achieve the objectives, experimental work in the quarries was carried out for separating marble block from the in situ strata as practiced in some of the Indian mines by using detonating cord of 30 to 50 g/m by varying hole spacing, hole diameter, air cushioning, water and sand filled blast-holes. Blasthole notching was carried out. Further, tests were carried out by using various liners inside the blasthole to determine the damages in the extracted block and remaining rock. The designed experimental work was undertaken and rock samples were collected by coring before and after blasting for quantification of microcrack in the rock. P-wave velocity and microscopic studies were conducted for quantification of damages. Experiments were also conducted at laboratory scale for the quantification of damages in single circular and notched holes with variation of stemming and liners. The P-wave velocity close to hole always reduces after blast and in case of NG-based charge and detonating cord it decreases up to 1/3^rd. With PVC pipe and paper tube liners decrease is negligible. Thus, by using notched hole with paper tube, decrease in P-wave is minimum indicating least damage.  相似文献   

Assessment of sedimentation in harakud reservoir using digital remote sensing technique     

D. S. Rathore  Anju Choudhary  P. K. Agarwal 《Journal of the Indian Society of Remote Sensing》2006,34(4):377-383

As per recommendations of Working Group for National Action for Reservoir Sedimentation Assessment, National Institute of Hydrology has taken up study on sedimentation for 25 reservoirs in India during X plan period using remote sensing technique. One such study for Hirakud reservoir in Mahanadi basin in Orissa for year 1999–2001 is described here. Reservoir’s original utilizable and gross volumes were 5818 and 8136 M m³, respectively. Minimum draw down level (MDDL) and full reservoir level (FRL) for reservoir are 179.83 and 192.02 m, respectively. Linear Imaging Self Scanning (LISS)- III data of Indian Remote Sensing Satellites (IRS) 1C and 1D, covering elevation range between 180.68 and 191.89 m, were used. Rule based classification was applied to ‘water index’ and radiances of near infrared band to determine water spread area. Revised live storage capacity was 4842 M m³. The silt index for the live storage area was 2.623 ha m (100 km² year)^-1 (0.376 % of live storage or 21.9 M m³ year^-1). Total live storage lost in sedimentation was 984 M m³ (16.90 % of live storage).  相似文献   

Effect of seabed instability on fixed offshore platforms     

Yasser E. Mostafa  M. Hesham El Naggar   《Soil Dynamics and Earthquake Engineering》2006,26(12):1127-1142

Storms, hurricanes, and earthquakes may cause seabed instability, especially if the seabed is weak. The seabed instability, manifested in movement of soil layers, exerts lateral forces that may cause large stresses in offshore foundations. The induced stresses may compromise the stability of the foundation and supported structure. The effect of seabed instability on a fixed offshore structure is examined in this study. The method used accounts for soil nonlinearity, dynamic soil resistance, and pile–soil–pile interaction within the stable soil layer. Dynamic p–y curves, dynamic t–z curves and q–z curves have been used to simulate the soil resistance in the lateral and axial directions. The effect of different parameters that influence the response of offshore structures to seabed instability is evaluated. The parameters considered include the value of soil movement, the sliding layer depth, the wave loading, the pile flexibility, the soil movement profile, and the axial loading at the pile head. The response predicted using the proposed analysis compared well with that calculated using a boundary element solution for a case history of a failed offshore platform.  相似文献   

Application of magnetic susceptibility anisotropy technique to the study of geological structures in the Armorican massif, France   总被引：1，自引：0，他引：1  

Jaswant Singh Rathore   《Tectonophysics》1979,60(3-4):207-216

Magnetic susceptibility anisotropy analyses have been carried out on 300 samples of rock from various metamorphosed regions of Normandy and Brittany, within the northern half of the Armorican massif, to test the ability of the magnetic fabric method (in a relatively complex region where structures have been well charted) to delineate regional structures. The two major structural directions to emerge from the study were a ENE—WSW striking magnetic foliation plane, conforming to a Variscan direction of the Bocaine syncline in the Granville region of Normandy and a ESE—WNW striking magnetic foliation plane conforming to the Armorican direction in the Chateaulin syncline region of Brittany. The magnetic fabric of sites elsewhere confirmed localised structures and minor synclinal structures.

The major advantages of the technique of studying magnetic fabric over petrofabric are the speed at which magnetic fabric can be measured (2 minutes per sample compared with up to 24 h using X-ray goniometry techniques) and the sensitivity of the magnetic fabric to very slight stresses.  相似文献   

Magnetic susceptibility anisotropy in the Cambrian slate belt of North Wales and correlation with strain   总被引：2，自引：0，他引：2  

J. S. Rathore 《Tectonophysics》1979,53(1-2)

The magnetic susceptibility anisotropy of 275 specimens comprising 38 sites from the Cambrian slate belt in North Wales was measured to determine the magnetic fabric of the slates. The susceptibility ellipsoid is oblate for all sites, and the maximum/intermediate susceptibility plane always coincides with the cleavage plane of the slates which has a Caledonian strike and is nearly vertical. The maximum axes align sub-vertically and the intermediate axes sub-horizontally, trending NE-SW. The minimum susceptibility axes are normal to this foliation plane and coincide with the poles to the slaty cleavage. The orientations of the principal susceptibility axes are found to be in excellent agreement with the orientations of the principal strain directions, determined by X-ray goniometry on one of the samples from almost all of the sites. Correlation of the magnetic susceptibility anisotropy with predicted March strains (March, 1932) shows that the principal magnitudes of susceptibility can be related to those of the strain by: (for i = 1, 2, 3. The orthogonal principal axes), where χ_f and χ₀ are the final and initial susceptibilities along a given axis i and l_f and l_i are final and initial axial dimensions in the same direction i of a principal strain axis. The exponent a for the North Wales slates was found to be 0.145 ± 0.005. Knowledge of such a relationship may permit rapid approximate determinations of a petrofabric in similar rocks from their magnetic fabrics. However, the exponent a will probably have to be recalibrated for each rock type.  相似文献   

Geospatial technology and structural analysis for geological mapping and tectonic evolution of Feiran–Solaf metamorphic complex,South Sinai,Egypt     

Mohamed O. Arnous  Yasser M. Sultan 《Arabian Journal of Geosciences》2014,7(8):3023-3049

The Sinai Peninsula constitutes an important district of the Egyptian lands where it forms a triangular portion in northeastern Egypt. The southern Sinai metamorphic complexes are the northern uppermost part of the Arabian–Nubian Shield revealing the upper and middle crust from the East African Orogeny, in which they tectonically evolved. The Feiran–Solaf metamorphic complex (FSMC) of Sinai, Egypt is one of the highest grades metamorphic complexes of a series of basement domes that trends NW and crops out throughout the Arabian–Nubian Shield. The main aim of the present study is to apply the geospatial technology and to represent the capability of the geospatial technology to estimate the combined influence of lithology and structure studies, and to construct the lithological and structural maps of FSMC. Furthermore, detailed structural analysis is carried out to reveal the different ductile and brittle deformational events and proposed the tectonic evolutionary model for the study area. Mainly geospatial technology and structural analysis software have been used to go well with the aim of the present study. Developing specific image processing of satellite images and structural analysis were succeeded to discriminate the various lithological rock units, and the geological structural features of the FSMC, using geographic information system tools to construct the different thematic maps, were extracted. The present detailed investigations of the enhanced satellite images, structural analysis, and field verification reveal that the FSMC reached its present tectonic setting through more than four deformational phases concluding that the Pan-African Najd Fault System continued in Sinai and was reactivated during Red Sea tectonics as indicated by the dextral shear zone (Rihba) bordering the northern side of the FSMC.  相似文献