Evidence of a possible north-south shift of the western sector of the African plate—Discussion     

N. J. Skinner 《Tectonophysics》1979,53(1-2)

A negative anomaly in the vertical magnetic field component at a site in Nigeria has recently been interpreted by Oni in terms of a possible north-south shift of the western sector of the African plate. In this paper, comments are made under the headings of magnetic field reversals, polar wander and secular variation, which cast doubt on Oni's interpretation.  相似文献   

XMM–Newton X-ray observations of the Wolf–Rayet binary system WR 147     

S. L. Skinner  S. A. Zhekov  M. Güdel  W. Schmutz 《Monthly notices of the Royal Astronomical Society》2007,378(4):1491-1498

We present results of an ≈20-ks X-ray observation of the Wolf–Rayet (WR) binary system WR 147 obtained with XMM–Newton . Previous studies have shown that this system consists of a nitrogen-type WN8 star plus an OB companion whose winds are interacting to produce a colliding wind shock. X-ray spectra from the pn and MOS detectors confirm the high extinction reported from infrared studies and reveal hot plasma including the first detection of the Fe Kα line complex at 6.67 keV. Spectral fits with a constant-temperature plane-parallel shock model give a shock temperature   kT _shock= 2.7  keV (   T _shock≈ 31  MK), close to but slightly hotter than the maximum temperature predicted for a colliding wind shock. Optically thin plasma models suggest even higher temperatures, which are not yet ruled out. The X-ray spectra are harder than can be accounted for using 2D numerical colliding wind shock models based on nominal mass-loss parameters. Possible explanations include: (i) underestimates of the terminal wind speeds or wind abundances, (ii) overly simplistic colliding wind models or (iii) the presence of other X-ray emission mechanisms besides colliding wind shocks. Further improvement of the numerical models to include potentially important physics such as non-equilibrium ionization will be needed to rigorously test the colliding wind interpretation.  相似文献   

Estimation of Shallow Geothermal Energy Resource in Canada: Heat Gain and Heat Sink     

Jacek Majorowicz  Stephen E. Grasby  Walter R. Skinner 《Natural Resources Research》2009,18(2):95-108

Maps of shallow depth (down to −250 m) temperature distribution across Canada show large variability, related mainly to surface climatic forcing. Very small changes of temperature with depth in the upper 250 m are related to heat gained by the subsurface due to recent global warming. Temperature data compiled from precise temperature logs in equilibrium wells, and temperature time series from a network of meteorological stations, allow calculation of the available heat energy for heating in the cold period and for cooling in peak warm months. Utilization of this energy resource has the potential for significant CO₂ reduction in Canada. The geothermal energy stored in the ground can be used, with the help of heat pumps, for heating, given very low winter temperatures. The amount of potential heat available is vast. In Canada, south of permafrost border, the integrated value of potentially available heat during the heating season down to −50 m is 1.1 E21 J (1100 quads).  相似文献   

Editor’s Message: 25 years of <Emphasis Type="Italic">Hydrogeology Journal</Emphasis>     

Clifford?I.?Voss  A.?C.??Skinner 《Hydrogeology Journal》2017,25(8):2217-2220

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Visibly in trouble: Northern Rock, a post-mortem on a financial crisis     

Alan G Hallsworth  Frank Skinner 《Area》2008,40(2):278-283

Here we seek to spatialise aspects of the Northern Rock Bank crisis of 2007 by marrying two radically different approaches. We combine a discussion of financial lending practices with an articulation of herd behaviour in conditions of uncertainty. Both were part of the still-unfolding picture of a traumatic episode in the geography of finance but also convey lessons on the behaviour of society in situations of shortage.  相似文献   

The onset of axial symmetry in protoplanetary nebulae     

C. J. Skinner  M. Meixner  M. J. Barlow  K. Justtanont  J. F. Arens  J. G. Jernigan 《Astrophysics and Space Science》1995,224(1-2):383-386

We have obtained resolved IR images, at wavelengths from 1.2µm to 12.5µm, of a small sample of protoplanetary nebulae. The results suggest that all PPNe are axially, not spherically, symmetric, that spherical symmetry ends at the tip of the AGB, and that AGB evolution terminates with a burst of remarkably rapid, equatorially concentrated mass-loss.  相似文献   

ISO LWS Observations of H2O from R Cas: A Consistent Model For Its Circumstellar Envelope     

Truong-Bach  Nguyen-Q-Rieu  R.J. Sylvester  M.J. Barlow  X.W. Liu  T. Lim  A. Omont  P. Cox  C.J. Skinner 《Astrophysics and Space Science》1997,255(1-2):325-328

We present an ISO LWS 43-197 μm grating spectrum of the oxygen-rich AGB star R Cas. The spectrum is rich of isolated and blended H2O lines. For their identification and in order to determine the physical parameters of the circumstellar envelope, we have constructed a model which treats radiative transfer, chemical exchange and photodissociation reactions, and various heating and cooling processes in a consistent manner. By fitting the observed line fluxes and using stellar parameters based upon the Hipparcos distance, we derived a mass-loss rate of M = 1 10-6 M⊙ yr-1 which is close to the value 6 10-7 M⊙ yr-1 previously derived for W Hya, another oxygen-rich AGB star. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Chandra X-ray observations of the young stellar cluster NGC 6193 in the Ara OB1 association     

S. L. Skinner  S. A. Zhekov  F. Palla  C. L. D. R. Barbosa 《Monthly notices of the Royal Astronomical Society》2005,361(1):191-205

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Sulfur electronic environments in α-NiS and β-NiS: examination of the relationship between coordination number and core electron binding energies     

Siew Wei Goh  Alan N. Buckley  Robert N. Lamb  William M. Skinner  Allan Pring  Haipeng Wang  Liang-Jen Fan  Ling-Yun Jang  Lee-Jene Lai  Yaw-wen Yang 《Physics and Chemistry of Minerals》2006,33(2):98-105

X-ray photoelectron spectra have been obtained under the same experimental conditions for synthetic α-NiS and natural β-NiS in order to establish any difference in S electronic environment, and to test the proposition that S core electron binding energies increase measurably with coordination number when the same metal is in different sulfide structures or lattice sites. The Ni and S electronic environments in the two NiS structures have been further probed by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and the NEXAFS spectra interpreted by reference to spectra simulated by ab initio calculations. The photoelectron and NEXAFS spectra for freshly prepared surfaces of α-NiS and β-NiS were found to be similar, with only subtle differences in electronic environment evident in the experimental and simulated NEXAFS spectra. The measured and calculated core electron binding energies did not support the previously postulated relationship between S coordination number and electron binding energies.  相似文献   

Galvanic interaction between grinding media and arsenopyrite and its effect on flotation: Part II. Effect of grinding on flotation     

Guozhi Huang  Stephen GranoW. Skinner 《International Journal of Mineral Processing》2006

Arsenopyrite floatability was correlated with the galvanic current, calculated from polarization curves measured during grinding, as well as the amount of oxidized iron, measured by EDTA extraction, in the mill discharge. The adverse influence of galvanic interaction during grinding on arsenopyrite floatability was quantified.  相似文献