Short communication block lanczos method for dynamic analysis of structures     

Bahram Nour-Omid  Ray W. Clough 《地震工程与结构动力学》1985,13(2):271-275

The simple Lanczos method presented in a recent paper by the writers, with application to single vector loads, is extended to include a more general dynamic loading represented as a linear combination of k vectors (load patterns). The result is a set of orthogonal vectors that is used to transform the equations of motion to a banded form, the half-bandwidth of which becomes k + 1. When k is small relative to the number of equations, this approach provides for a very efficient time-stepping solution.  相似文献   

Tank damage during the may 1983 coalinga earthquake     

George C. Manos  Ray W. Clough 《地震工程与结构动力学》1985,13(4):449-466

The magnitude M = 6-5 Coalinga earthquake of 2 May 1983 caused intense ground shaking throughout the epicentral region. Unanchored cylindrical ground supported tanks located at six sites within this oil producing area were damaged; damages included elephant's foot buckling at the base of three moderate sized tanks, joint rupture and top shell buckling in one large old rivetted tank, bottom plate rupture of a relatively new welded tank and damage to the floating roofs of 11 tanks. Also oil spilled over the top of many tanks and secondary damages occurred in pipe connections, ladders, etc. In this paper an estimate is made of the intensity of ground motion at each of the tank sites, based on strong motion records made during the main shock and the strongest aftershock. Then response parameters specified by current codes are correlated with the damages observed at each tank site. Based on this comparison, it is concluded that current U.S. practice under-estimates the sloshing response of tanks with floating roofs and does not adequately address the uplifting mechanism of unanchored ground supported tanks.  相似文献   

Trace metal distributions in Saint John Harbour sediments     

S. Ray  S.D. Macknight 《Marine pollution bulletin》1984,15(1):12-18

The concentration and areal distribution of selected trace metals (Cu, Zn, Pb, Cd, Mo, Ni, Mn and Hg) in surficial sediments of Saint John Harbour, New Brunswick, Canada, were studied to determine the extent of anthropogenic input and to estimate the effects of dumping dredged material in the outer harbour. Hg and Cd are of especial concern, since the disposal of dredge material containing these two elements is regulated under the Ocean Dumping Control Act.The concentrations of all metals are low: Cu 16, Zn 53, Pb 24, Cd 0.16, Mo 3, Ni 16, Mn 296 and Hg 0.04 μg g^?1. Hg and Cd levels in sediments are well below the permissible limits of 0.75 and 0.6 μg g^?1, respectively, set by the Ocean Dumping Control Act.The mean concentrations of trace elements are similar to the low mean values in the unpolluted Bay of Fundy. There is an overall decline in concentrations of metals in the sediments from the inner to the outer harbour. Comparison of the metal levels in the sediments from different areas within the harbour indicate that there is a detectable anthropogenic input in the Courtenay Bay area. Trace metal levels at the dumpsite are significantly lower than in the Courtenay Bay area, where the bulk of the dredged material originates.  相似文献   

Geochemical and petrological relations in some deccan basalts, Western Maharashtra, India     

D.K. Paul  P. Kresten  T. Ray Barman  R.H. McNutt  A.O. Brunfelt 《Journal of Volcanology and Geothermal Research》1984,21(1-2)

Petrographic and geochemical data are given for some basaltic rocks from the Koynaghat, Ambaghat and Panvel sections of the western Deccan volcanic province. This study confirms geochemical features established earlier for the Deccan basalts but brings out minor additional characters. Mineralogical and major-element compositions of the basaltic flows from the Koyna and Panvel sections indicate tholeiitic affinity; the Ambaghat flows exhibit a slight affinity towards alkali basalt. Rare earth element (REE) distribution patterns and trace-element abundances suggest minor fractionation of olivine and plagioclase during the evolution of the flows. The general similarity of chemical and mineralogical features over a wide area and the lack of conspicuous inter-element relationships suggest that the flows reflect the combined effects of partial melting, minor mineral fractionation and selective crustal contamination.  相似文献   

Variable eddy diffusivities and atmospheric cellular convection     

Durga Ray 《Boundary-Layer Meteorology》1986,36(1-2):117-131

Using variable atmospheric eddy diffusivities, it is possible to obtain a theoretical explanation of observations concerning the increase of cell flatness in cellular cloud patterns. The inclusion of a horizontal variation of eddy size as proposed by Ray (1965) and supported by Agee (1973) has a large influence on theoretical Rayleigh number and cell shape, the degree of cell flatness being principally controlled by the degree of horizontal variation of the eddies. It is also shown that observations regarding the reversal of the circulation pattern could be interpreted on the basis of eddy diffusivities that change sign along the reference directions. This suggests that it may be useful to rethink our ideas about the existence of spatial variations in the eddy transfer coefficients in atmospheric convection.  相似文献   

Analytical correlation of a dynamic brace buckling experiment     

Yusof Ghanaat  Ray W. Clough 《地震工程与结构动力学》1983,11(1):111-120

A dynamic response analysis procedure for an x-braced tubular steel offshore platform frame is described, including details of the mathematical model adopted to represent the dynamic buckling behaviour of the brace member. Results obtained with this mathematical technique are compared with experimental data measured during shaking table tests of a 5/48 scale model frame. The agreement between experiment and analysis is excellent for different levels of response, ranging from linearly elastic to cyclic brace buckling.  相似文献   

Progress in Carrier Phase Time Transfer   总被引：1，自引：0，他引：1  

Jim Ray  Felicitas Arias  Gérard Petit  Tim Springer  Thomas Schildknecht  Jon Clarke  Jan Johansson 《GPS Solutions》2001,4(4):47-54

The progress of the joint Pilot Project for time transfer, formed by the International GPS Service (IGS) and the Bureal International des Poids et Mesures (BIPM), was recently reviewed. Three notable milestones were set. (1) The IGS will implement, at least in a test mode, an internally realized time scale based on an integration of combined frequency standards within the IGS network. This will eventually become the reference time scale for all IGS clock products (instead of the current GPS broadcast time). (2) A new procedure for combined receiver and satellite clock products will be implemented officially in November 2000. Receiver clocks are an entirely new product of the IGS. (3) The BIPM will coordinate an effort to calibrate all Ashtech Z12-T (and possibly other) receivers suitable for time transfer applications, either differentially or absolutely. Progress reports will be presented publicly in the spring 2001. ? 2001 John Wiley & Sons, Inc.  相似文献   

Temperature Sensitivity of Timing Measurements Using Dorne Margolin Antennas     

J. R. Ray  K. Senior 《GPS Solutions》2001,5(1):24-30

We have inferred the temperature sensitivity of Dorne Margolin choke ring antennas by direct estimation from differential clock estimates for two GPS sites separated by 2400 km. At each site, the cable and receiver systems are very well isolated from environmental variations. By direct comparison of the observed clock variations between these sites with local temperature measurements, empirical temperature coefficients for each system have been estimated. These thermal coefficients most likely apply to the only uncontrolled components of the systems, the Dorne Margolin choke ring antennas. Based on these results, the short-term (diurnal) stability of the antennas appears to be better than 2 ps/°C. The possibility that longer-term effects exist due to sensitivity in the daily average of the pseudorange observations has not been tested and cannot be excluded. ? 2001 John Wiley & Sons, Inc.  相似文献   

40Ar-39Ar age of carbonatite-alkaline magmatism in Sung valley, Meghalaya, India     

Jyotiranjan S Ray  Kanchan Pande 《Journal of Earth System Science》2001,110(3):185-190

⁴⁰Ar-³⁹Ar analyses of one alkali pyroxenite whole rock and two phlogopite separates of calcite carbonatites from the Sung Valley carbonatite-alkaline complex, which is believed to be a part of the Rajmahal-Bengal-Sylhet (RBS) flood basalt province, yielded indistinguishable plateau ages of 108.8 ± 2.0Ma, 106.4 ± 1.3Ma and 107.5 ± 1.4Ma, respectively. The weighted mean of these ages, 107.2 ± 0.8 Ma, is the time of emplacement of this complex. This implies that Sung Valley complex and probably other such complexes in the Assam-Meghalaya Plateau postdate the main flood basalt event (i.e., the eruption of tholeiites) in the RBS province by ∼10Ma.  相似文献   

High iridium concentration of alkaline rocks of Deccan and implications to K/T boundary     

P. N. Shukla  N. Bhandari  Anirban Das  A. D. Shukla  J. S. Ray 《Journal of Earth System Science》2001,110(2):103-110

We report here an unusually high concentration of iridium in some alkali basalts and alkaline rocks of Deccan region having an age of about 65Ma, similar to the age of the Cretaceous-Tertiary boundary. The alkali basalts of Anjar, in the western periphery of Deccan province, have iridium concentration as high as 178pg/g whereas the alkaline rocks and basalts associated with the Amba Dongar carbonatite complex have concentrations ranging between 8 and 80 pg/g. Some of these values are more than an order of magnitude higher than the concentration in the tholeiitic basalts of Deccan, indicating the significance of alkaline magmatism in the iridium inventory at the Cretaceous-Tertiary boundary. Despite higher concentration, their contribution to the global inventory of iridium in the Cretaceous-Tertiary boundary clays remains small. The concentration of iridium in fluorites from Amba Dongar was found to be <30 pg/g indicating that iridium is not incorporated during their formation in hydrothermal activity.  相似文献