Global Environmental Issues - Edited by Frances Harris     

Frank  Chambers 《The Geographical journal》2006,172(3):266-267

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Inversion of 2D spectral induced polarization imaging data   总被引：1，自引：0，他引：1  

M.H. Loke  J.E. Chambers  R.D. Ogilvy 《Geophysical Prospecting》2006,54(3):287-301

Laboratory measurements of various materials suggest that more information can be obtained by measuring the in‐phase and out‐of‐phase potentials at a number of frequencies. One common model used to describe the variation of the electrical properties with frequency is the Cole‐Cole model. Apart from the DC resistivity (ρ) and chargeability (m) parameters used in conventional induced‐polarization (IP) surveys, the Cole‐Cole model has two additional parameters, i.e. the time (τ) and relaxation (c) constants. Much research has been conducted on the use of the additional Cole‐Cole parameters to distinguish between different IP sources. Here, we propose a modified inversion method to recover the Cole‐Cole parameters from a 2D spectral IP (SIP) survey. In this method, an approximate inversion method is initially used to construct a non‐homogeneous starting model for the resistivity and chargeability values. The 2D model consists of a number of rectangular cells with constant resistivity (ρ), chargeability (m), time (τ) and relaxation (c) constant values in each cell. A regularized least‐squares optimization method is then used to recover the time and relaxation constant parameters as well as to refine the chargeability values in the 2D model. We present results from tests carried out with the proposed method for a synthetic data set as well as from a laboratory tank experiment.  相似文献   

The time behavior of temperature and emission measure in X-ray flares     

Robert W. Milkey  Norman K. Blocker  William H. Chambers  Paul E. Fehlau  Jack C. Fuller  Walter E. Kunz 《Solar physics》1971,20(2):400-412

X-ray observations from Vela-5 spacecraft of five flares occurring in November and December 1969 were leduced to temperatures and emission measures as a function of time. This reduction was done assuming a thermal spectrum including free-free and free-bound emission. A phenomenological model is proposed to explain the nature of the time behavior of the temperature and emission measure.Solar Division, Kitt Peak National Observatory, P. O. Box 4130, Tucson, Arizona 85717.Major USAF, AFWL/SAY, Kirtland Air Force Base, Albuquerque, New Mexico.  相似文献   

Fractionation and assimilation in the Borgtinderne syenite,East Greenland     

P. E. Brown  R. D. Brown  A. D. Chambers  N. J. Soper 《Contributions to Mineralogy and Petrology》1978,67(1):25-34

The Borgtinderne nepheline-sodalite syenite is one of the major intrusions in the Tertiary igneous province of East Greenland. The syenite magma, which was evolving towards an undersaturated peralkaline residuum, underwent extensive modification by incorporation of country rock basalt, resulting in the production of a variety of hybrid syenites. Major element variation in the hybrids is essentially linear. Break-up and mechanical incorporation of the basic material was aided by amphibolitisation and metasomatism of the basalt xenoliths.  相似文献   

The Lilloise intrusion,east Greenland: Hydrogen isotope evidence for the efflux of magmatic water into the contact metamorphic aureole     

S. M. F. Sheppard  P. E. Brown  A. D. Chambers 《Contributions to Mineralogy and Petrology》1977,63(2):129-147

The epizonal, Tertiary Lilloise layered intrusion (5–9 km diameter) has a well developed amphibolitised basalt aureole, several hundred metres wide. The sequence of main cumulate minerals is olivine, augite, plagioclase, amphibole (Ti-hornblende to hastingsite), with amphibole first appearing as an intercumulus mineral about 2000 m below the present top of the intrusion. The range of D and ¹⁸O values (SMOW) of amphiboles and biotites from early intercumulus, and cumulus minerals and late pegmatites is very narrow, -70 to -88 and +4.3 to 5.5 respectively. Amphiboles or whole rocks from the basaltic country rocks change from D= -85 near the contact to -116 in the outer part of the aureole, and to -118 in the non-metamorphosed basalts up to 9km away. All basalts are depleted in ¹⁸O relative to normal values with the largest depletion (up to 2–3) in the outer part of the aureole. Meteoric water did not interact with either the magma or the hot plutonic rocks. This is in contrast to the results from most other plutonic complexes in the North Atlantic Tertiary igneous province (Skaergaard, Kangerdlugssuaq, Skye, etc.) many of which were similarly emplaced into basaltic country rocks. A meteoric-hydrothermal convective system was established in the basalts including the inner contact zone prior to the complete crystallisation of the Lilloise magma. The inner part of the aureole was finally modified by magmatic-hydrothermal fluids which evolved non explosively from the Lilloise magma. The meteoric-hydrothermal system in the outer part of the aureole, with integrated water/rock ratios of about 0.2 (atom % oxygen), did not collapse in on the hot pluton or inner contact metabasalts. Several factors may have reduced the permeability of the basalt country rocks. The emplacement of dykes prior to the Lilloise intrusion and possible associated weak hydrothermal activity could have restricted circulation of meteoric water; major fracture permeability was not generated during the quiet non-explosive crystallisation history of the Lilloise single magma pulse; metasomatism and alteration accompanying the magmatic-hydrothermal fluids may have reduced permeabilities in the inner aureole. Meteoric waters, however, did enter locally, at a very late stage, during low temperature serpentinisation of periodotite.  相似文献   

Effect of the separation between cold wires on the spatial derivatives of temperature in a turbulent flow     

L. W. B. Browne  R. A. Antonia  A. J. Chambers 《Boundary-Layer Meteorology》1983,27(2):129-139

An analysis is made of the effect of spatial separation of a pair of parallel temperature sensors on the variance and spectrum of spatial temperature derivatives in a turbulent flow. The results of the analysis are compared with experimental results obtained when the separation between the sensors is in a direction either perpendicular or parallel to that of the main stream.  相似文献   

Relationships between structure functions and temperature ramps in the atmospheric surface layer     

R. A. Antonia  A. J. Chambers  E. F. Bradley 《Boundary-Layer Meteorology》1982,23(4):395-403

The behaviour of odd-order structure functions of temperature in the atmospheric surface layer is consistent with the presence of a coherent structure characterised by temperature ramps. The use of a simple linear model for the ramp together with measurements of second-, third-, and fifth-order temperature structure functions yields estimates for the characteristic mean amplitude and repetition interval of ramps for stability conditions ranging from neutral to moderately unstable. Both amplitude and repetition interval compare favourably with values derived from observations of temperature traces obtained simultaneously at two heights in the surface layer.  相似文献   

Streamwise heat flux budget in the atmospheric surface layer     

E. F. Bradley  R. A. Antonia  A. J. Chambers 《Boundary-Layer Meteorology》1982,23(1):3-15

Atmospheric surface-layer measurements of terms in the equation for the streamwise heat flux confirm previous results in both laboratory and atmosphere that the temperature-pressure gradient correlation acts as a sink, approximately equal in magnitude to the production term. The measured viscous dissipation term is independent of stability and represents less than 10% of the production term over the range of experimental stability conditions. Models for the temperature-pressure gradient correlation are compared with the measurements.  相似文献   

Strength of Rock-Like Specimens with Pre-existing Cracks of Different Length and Width     

Ivan Gratchev  Dong Hyun Kim  Chong Kit Yeung 《Rock Mechanics and Rock Engineering》2016,49(11):4491-4496

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N-Body Simulations of Planet Formation Varying the Initial Number of Planetary Embryos     

Chambers  J.E. 《Earth, Moon, and Planets》1998,81(1):3-6

Earth, Moon, and Planets -  相似文献