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131.
132.
A temperature-transient method to estimatein situ formation thermal conductivity and equilibrium formation temperature using circulation fluid flow-rate pulses is described. Flow-rate changes induce temperature variations in the well and the time from when the flow alters to the subsequent maximum or minimum temperature of the drilling fluid can be used to determine these two formation parameters. Some examples are presented to illustrate the method. 相似文献
133.
Drop calorimetry measurements between 900 and 1850 K are reported for amorphous anorthite, andesine, wollastonite, diopside, cordierite and pyrope. The isobaric heat capacities of the glassy and liquid phases of these materials, and the enthalpies of fusion of the minerals have been derived. The calorimetric entropies of fusion of these substances and of other oxide minerals are generally consistent with the calculated volume changes on melting and with the observed pressure dependences of the melting points. The thermodynamics of mixing of liquid plagioclases have been examined, and it is concluded that their enthalpies of mixing are markedly different from the values derived directly from solution calorimetry measurements at 985 K. 相似文献
134.
Estimating species diversity: Comparison of two algorithms 总被引:2,自引:0,他引:2
Pascal de Caprariis 《Mathematical Geology》1984,16(3):237-248
Two approaches to estimating the number of species in a lithologic unit are compared. An empirical model of the sampling process, which involves fitting the equation of a rectangular hyperbola to the data from a collector's curve, is compared with a logarithmic model derived from a statistical theory of sampling. The two approaches give equally accurate estimates of species richness when organisms are randomly dispersed but the logarithmic model generally requires more sampling than the hyperbolic model. 相似文献
135.
Summary A three-dimensional numerical model of the divided-bar thermal conductivity measuring device that can include both solid and fluid sample portions has been developed. The model has been employed to investigate the effects of porosity in divided-bar measurements and the effects of the distribution of solid sample and contained fluids in porous material on the thermal conductivity calculated from the bar temperature measurements. The results show that the positions of the temperature sensors and thus the nature of the vertical column between the temperature measuring points is of prime importance, and that the sizes of the solid and fluid portions of the sample affect the sample conductivity estimates. The divided bar measures the thermal conductivity parallel to the axis of the bar. Thermal conductivity variations in the radial direction have little effect on the calculated conductivity. Whether or not the sides of the bar are insulated strongly affects the calculated conductivity.Presented at the International Meeting on Terrestrial Heat Flow and the Structure of Lithosphere, Bechyn Castle, Czech Republic, September 2 – 7, 1991. 相似文献
136.
In single‐streamer acquisition, the use of acoustic transducers to constrain the receiver positions is not possible, thus implying the use of compass birds to gather information on the streamer location. The compasses are, however, sensitive to the declination of the local magnetic field of the earth, and local fluctuations not accounted for can degrade the accuracy of reconstructed positions. In order to correct these small‐scale fluctuations, we propose a simple deterministic method to calculate a spatial correction to apply to the compasses that enhances the positioning accuracy. The local compass declination is calculated after a first reconstruction on the whole survey area. This method was applied with success to navigation data from a 3D survey offshore Japan, and the positioning accuracy was improved to the level of the DGPS accuracy. 相似文献
137.
Jean-François Royer Daniel Cariolle Fabrice Chauvin Michel Déqué Hervé Douville Rong-Ming Hu Serge Planton Annie Rascol Jean-Louis Ricard David Salas Y Melia Florence Sevault Pascal Simon Samuel Somot Sophie Tyteca Laurent Terray Sophie Valcke 《Comptes Rendus Geoscience》2002,334(3):147-154
Two climate simulations of 150 years, performed with a coupled ocean/sea-ice/atmosphere model including stratospheric ozone, respectively with and without heterogeneous chemistry, simulate the tropospheric warming associated with an increase of the greenhouse effect of carbon dioxide and other trace gases since 1950 and their impact on sea–ice extent, as well as the stratospheric cooling and its impact on ozone concentration. The scenario with heterogeneous chemistry reproduces the formation of the ozone hole over the South Pole from the 1970s and its deepening until the present time, and shows that the ozone hole should progressively fill during the coming decades. To cite this article: J.-F. Royer et al., C. R. Geoscience 334 (2002) 147–154. 相似文献
138.
Muriel Llubes Nicolas Florsch Jean-Paul Boy Martine Amalvict Pascal Bonnefond Marie-Noëlle Bouin Stphane Durand Marie-France Esnoult Pierre Exertier Jacques Hinderer Marie-Franoise Lalancette Frdric Masson Laurent Morel Joëlle Nicolas Mathilde Vergnolle Guy Wppelmann 《Comptes Rendus Geoscience》2008,340(6):379-389
We have organised afield study of ocean tide loading in the northwestern part of France, where tidal amplitudes are known to be among the highest in the world. GPS and gravimetric techniques have already proved their capability to measure such weak and high-frequency signals. In this study, these classical observations are complemented with less usual techniques, such as tiltmeter and Satellite Laser Ranging (SLR) measurements. We present here the preliminary results for a common period of observations spanning from 12–19 May 2004. Additional measurements from the French Transportable Laser Ranging Station (FTLRS) were available during September and October 2004. Observation residuals are computed as the difference between the observed and the predicted time signals. We obtain small RMS residuals for GPS measurements (2.5/3.1/4.5 mm for the eastward, northward and upward components), for absolute and relative gravimetry (9 nm/s2 and 13 nm/s2) and for tiltmeters (0.05 μrad for EW component). We also fit the amplitude of the main M2 tidal constituent to FTLRS observations and we find a value of 3.731 cm, which is comparable to the theoretical value. 相似文献
139.
Nicolas Lepage Pascal Hamel René Lefebvre René Therrien Chantale Blais 《Ground Water Monitoring & Remediation》1999,19(3):157-170
The municipal landfill at the Complexe Environnemental de Saint-Michel (CESM) in Montreal, which is the third largest in North America, is located in a former quarry in fractured limestone. Impressive measures are taken to monitor and control biogas and leachate generated at the site. Leachate containment is presently performed with a pumping well completed within the waste. The efficiency of the well in controlling off-site leachate migration is questioned because field observations strongly suggest that the nearby former Francon quarry is diverting local ground water flow. To address this issue, four additional hydraulic control options are considered: (1) increased pumping at the existing waste well; (2) new pumping wells in the rock on the eastern limit of the site; (3) new injection wells in the rock on the eastern limit; and (4) combination of new injection wells at the same location and new water supply wells upgradient of the landfill. We evaluated the four hydraulic control options at the CESM using two coupled models: (1) a decision model based on an objective function weighting the risk, costs, and benefits of each option translated into dollar units; and (2) a numerical ground water flow model to represent the effect of operational conditions and ascertain success. Decision analysis offers a quantitative unbiased tool to evaluate the potential and relative cost of each option, but qualitative considerations and judgment still must be used for a complete evaluation. Our analysis confirms that scenario 4, which was the intuitively favored option, represents the best containment strategy. 相似文献
140.
Raphaël Paris Simon Falvard Catherine Chagué James Goff Samuel Etienne Pascal Doumalin 《Sedimentology》2020,67(3):1207-1229
X-ray tomography is used to analyse the grain size and sedimentary fabric of two tsunami deposits in the Marquesas Islands (French Polynesia, Pacific Ocean) which are particularly exposed to trans-Pacific tsunamis. One site is located on the southern coast of Nuku Hiva Island (Hooumi) and the other one is on the southern coast of Hiva Oa Island (Tahauku). Results are compared with other techniques such as two-dimensional image analysis on bulk samples (particle analyser) and anisotropy of magnetic susceptibility. The sedimentary fabric is characterized through three-dimensional stacks of horizontal slices (following a vertical step of 2·5 mm along the cores), while grain-size distribution is estimated from two-dimensional vertical slices (following a step of 2 mm). Four types of fabric are distinguished: (a) moderate to high angle (15 to 75°); (b) bimodal low-angle (<15°); (c) low to high angle with at least two different orientations; and (d) dispersed fabric. The fabric geometry in a tsunami deposit is not only controlled by the characteristics of the flow itself (current strength, flow regime, etc.) but also sediment concentration, deposition rate and grain-size distribution. There is a notable correlation between unimodal high-angle fabric – type (a) – and finely-skewed grain-size distribution. The two tsunami deposits studied represent two different scenarios of inundation. As demonstrated here, X-ray tomography is an essential method for characterizing past tsunamis from their deposits. The method can be applied to many other types of sediments and sedimentary rocks. 相似文献