Orlando '90 optical engineering and photonics in aerospace sensing: 16–20 April 1990, Orlando-USA     

Daniel St-Germain Courcelette 《ISPRS Journal of Photogrammetry and Remote Sensing》1990,45(5-6)

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The Little Ice Age : By Jean Grove. Methuen Publishers, London/New York, 498 pp     

Daniel H. Mann 《Quaternary Research》1990,34(3)

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Multilayer Sampling in the Water-Table Region of a Sandy Aquifer     

Edward Kaplan  Sujit Banerjee  Daniel Ronen  Mordeckai Magaritz  Albert Machlin  Michael Sosnow  Eric Koglin 《Ground water》1991,29(2):191-198

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On The Relationship Between Connectivity And The Continuum Approximation In Fracture-Flow And Transport Modelling     

F. P. M. Guérin  D. M. Billaux 《Hydrogeology Journal》1994,2(3):24-31

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High concentration of solutes at the upper part of the saturated zone (water table) of a deep aquifer under sewage-irrigated land     

Daniel Ronen  Mordeckai Magaritz 《Journal of Hydrology》1985,80(3-4):311-323

The water-table region (upper 50 cm of the saturated zone) of a 25 m deep phreatic sandstone aquifer, lying under fields irrigated with sewage effluents for up to 22 yrs, was monitored in 1971 and 1984. Average concentrations of NO⁻₃, Cl⁻ and SO²⁻₄ of up to 225, 307 and 155 mg l⁻¹, respectively, were detected in the upper 50 cm of the saturated region in two research wells in 1984. These concentrations, which are related to effluent and fertilizer input to groundwater, were two to four times higher than those found deep (37–55 m) below the water table in nearby (1000 m distant) production wells. Nitrate data and the estimated transit time through the unsaturated zone (2 m yr⁻¹) support the model suggesting that the major source of nitrate pollution in the past should be related to the oxidation of soil organic matter. The SO²⁻₄/Cl⁻ ratio is found to be a useful indicator for the arrival of SO²⁻₄-fertilizers at the groundwater interface. The observations presented in this paper question the suitability of plans for using effluents as a water source for agriculture in regions which are the replenishment areas of phreatic aquifers.  相似文献   

Extension of the specific interaction model to include gas solubilities in high temperature brines     

Leslie Barta  Daniel J. Bradley 《Geochimica et cosmochimica acta》1985,49(1):195-203

A semi-empirical model for gas solubilities in high temperature brines was developed by modification of the Pitzer interaction model (Pitzer, 1973) and evaluated by least-squares fitting to available P-T-X data for carbon dioxide, hydrogen sulfide, and methane in pure water and in aqueous sodium chloride solutions. Over the range of experimental data used (25°–350°C, NaCl concentration 0–6 m, P_CO2 1–150 atm. P_CH4 1–30 atm, P_CH4 1–1700 atm), standard deviations of fit in the natural logarithm of the Henry's law ratio were 0.096 for CO₂, 0.093 for H₂S and 0.116 for CH₄.The model has several advantages. First, it has a theoretical basis which can easily be extended for the inclusion of more than one salt or gas. Second, the equations simplify to the empirically derived equation of Setschenow, in the limit of infinite dilution. Finally, the model is easily integrated into a framework of equations which can yield all of the thermodynamic properties of the system.An example in which values of the model parameters for interaction of gas with salt may be used to estimate the effect of dissolved gas or salt solubility is given.  相似文献   

The geochemistry of Ca,Sr, Ba and Ra sulfates in some deep brines from the Palo Duro Basin,Texas     

Donald Langmuir  Daniel Melchior 《Geochimica et cosmochimica acta》1985,49(11):2423-2432

The geochemistry of Ca, Sr, Ba and Ra sulfates in some deep brines from the Palo Duro Basin of north Texas, was studied to define geochemical controls on radionuclides such as ⁹⁰Sr and ²²⁶Ra. Published solubility data for gypsum, anhydrite, celestite, barite and RaSO₄ were first reevaluated, in most cases using the ion interaction approach of Pitzer, to determine solubility products of the sulfates as a function of temperature and pressure. Ionic strengths of the brines were from 2.9 to 4.8 m, their temperatures and pressures up to 40°C and 130 bars. Saturation indices of the sulfates were computed with the ion-interaction approach in one brine from the arkosic granite wash fades and four from the carbonate Wolfcamp Formation. All five brines are saturated with respect to gypsum, anhydrite and celestite, and three of the five with respect to barite. All are undersaturated by from 5 to 6 orders of magnitude with respect to pure RaSO₄. ²²⁶Ra concentrations in the brines, which ranged from 10^?11.3 to 10^?12.7 m, are not controlled by RaSO₄ solubility or adsorption, but possibly by the solubility of trace Ra solid solutions in sulfates including celestite and barite.  相似文献   

Determination of Boron in 35 International Geochemical Reference Materials by Thermal Neutron Capture Prompt Gamma-ray Spectrometry     

Ernest S. GLADNEY  David B. CURTIS  Daniel R. PERRIN 《Geostandards and Geoanalytical Research》1984,8(1):43-46

Concentrations of boron in 35 silicate reference materials are measured by thermal neutron capture gamma-ray spectrometry. Results are compared for NBS, USGS, and CCRMP reference materials with values from the literature. The use of two prompt gamma facilities at Los Alamos are discussed.  相似文献   

A new parameterization of eddy diffusivities for nocturnal boundary-layer modeling     

Claude Estournel  Daniel Guedalia 《Boundary-Layer Meteorology》1987,39(1-2):191-203

Exchange coefficients and mixing lengths under stable stratification have been studied through measurements of mean wind velocity and temperature in the nocturnal boundary layer. For values of the gradient Richardson number lower than 0.15, our measurements fit well the relation of Delage (1974). Beyond Ri = 0.15, the decrease of mixing length is much slower. So a new parameterization of turbulent exchanges is suggested. When introduced in a model of the nocturnal boundary layer, it results in a thickening of the turbulent and inversion layers.  相似文献   

Submarine lava tubes and channels     

Daniel J. Fornari 《Bulletin of Volcanology》1986,48(5):291-298

High-resolution, side-looking sonar surveys of the East Pacific rise and seamounts in the eastern Pacific have revealed the common presence of lava tubes and channels in seafloor volcanic terrains. Tube and channel systems commonly issue from small volcanic cones or domes, are continuous for distances of 1–3 km, and are considered to be important in distributing lavas around seafloor extrusive sites and creating characteristic morphology. Eruption rate and volume are probably the most important controlling factors in determining whether tubes or channels will form. Volatile content and state, slope angle, and preeruption surface morphology are secondary factors that influence the ease with which a tube or channel may form and its direction and shape. Seafloor tubes and channels may also have a profound influence on the structure and evolution of the upper oceanic crust. Tubes and channels are likely to form intracrustal horizontal pathways for circulating hydrothermal fluids. Flow differentiation processes acting within tubes and channels may affect the chemical composition of lavas and could be partially responsible for the chemical diversity of rocks along accretionary boundaries. Seafloor tubes and channels that are either partially water-filled or contain volcaniclastics which are then buried within the volcanic pile can lower the compressional velocity and seismic response of the upper oceanic crustal layer along spreading axes.  相似文献