The structure and dynamics of 2-dimensional fluids in swelling clays   总被引：3，自引：0，他引：3  

Neal T. Skipper  Peter A. Lock  James O. Titiloye  Jan Swenson  Zakaria A. Mirza  W. Spencer Howells  Felix Fernandez-Alonso 《Chemical Geology》2006,230(3-4):182-196

The interlayer pores of swelling 2:1 clays provide an ideal 2-dimensional environment in which to study confined fluids. In this paper we discuss our understanding of the structure and dynamics of interlayer fluid species in expanded clays, based primarily on the outcome of recent molecular modelling and neutron scattering studies. Counterion solvation is compared with that measured in bulk solutions, and at a local level the cation-oxygen coordination is found to be remarkably similar in these two environments. However, for the monovalent ions the contribution to the first coordination shell from the clay surfaces increases with counterion radius. This gives rise to inner-sphere (surface) complexes in the case of potassium and caesium. In this context, the location of the negative clay surface charge (i.e. arising from octahedral or tetrahedral substitution) is also found to be of major importance. Divalent cations, such as calcium, eagerly solvate to form outer-sphere complexes. These complexes are able to pin adjacent clay layers together, and thereby prevent colloidal swelling. Confined water molecules form hydrogen bonds to each other and to the clays' surfaces. In this way their local environment relaxes to close to the bulk water structure within two molecular layers of the clay surface. Finally, we discuss the way in which the simple organic molecules methane, methanol and ethylene glycol behave in the interlayer region of hydrated clays. Quasi-elastic neutron scattering of isotopically labelled interlayer CH₃OD and (CH₂OD)₂ in deuterated clay allows us to measure the diffusion of the CH₃- and CH₂-groups in both clay and liquid environments. We find that in both the one-layer methanol solvates and the two-layer glycol solvates the diffusion of the most mobile organic molecules is close to that in the bulk solution.  相似文献   

Large glass inclusions in plagioclase phenocrysts and their bearing on the origin of mixed andesitic lavas at Tolimán volcano,Guatemala     

Sid P. Halsor 《Bulletin of Volcanology》1989,51(4):271-280

Irregularly shaped, large and clear (LAC) glass inclusions are present in plagioclase phenocrysts in several andesitic lavas erupted from Tolimán volcano, Guatemala. Their morphology is different from densely spaced, fine-grained glass inclusions that form concentric zones in dusty or cellular textured plagioclase phenocrysts. The large size of LAC inclusions make them suitable for microprobe analysis and average bulk compositions are presented for glasses in 30 phenocrysts from eight lava samples. Their compositions are rhyolitic and in disequilibrium, or out-range (Anderson 1976) with respect to whole-rock and groundmass glass compositions. LAC inclusions typically occur in large, tabular plagioclase phenocrysts with relatively uniform, sodic compositions (An 40–54). Compositions of feldspar phenocrysts not containing LAC inclusions range from An 41 to An 81. Petrographic and chemical data support a primary origin for LAC glasses, suggest mixing of mafic and silicic magmas, and also constrain a mechanism for magma mixing. Rapid growth of plagioclase and entrapment of LAC glass occurs during mixing in a vapor-rich silicic liquid under low degrees of undercooling. These conditions are possibly produced in a high-level magma body such as that envisioned by Huppert et al. (1982), where replenishment and subsequent crystallization of a hydrous magma induces density instability and mixing with the resident magma.  相似文献   

Earthquake design practice for buildings by David E. Key,Thomas Telford publications,London, 1988. no. of pages: 218: U. K. £35; overseas £40 by air     

D. A. Howells 《地震工程与结构动力学》1989,18(3):454-454

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GESAMP reports     

G.D. Howells 《Marine pollution bulletin》1984,15(9):319

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A history of Persian earthquakes,by N. N. Ambraseys and C. P. Melville,Cambridge University Press,Cambridge, 1982. No. of pages: 219. Price: £35     

D. A. Howells 《地震工程与结构动力学》1983,11(4):591-591

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Engineering for protection from natural disasters,Edited By P. Karasudhi,A. S. Balasubramaniam and W. Kanok-Nukulchai,Wiley, Chichester, 1980. No. of Pages: 950. Price: $101.00/£35.00     

D. A. Howells 《地震工程与结构动力学》1981,9(5):518-518

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In and out of hot water     

Gwyneth Howells 《Marine pollution bulletin》1977,8(11):245-248

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Smoothed Particle Hydrodynamics for modelling landslide–water interaction problems     

Mahallem  Abderrahmane  Roudane  Mohamed  Krimi  Abdelkader  Gouri  Sid Ahmed 《Landslides》2022,19(5):1249-1263

Landslides - This work aims to develop a Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) in-house code for modelling landslide–water interaction problems. While we consider the...  相似文献   

New chelating resin for preconcentration and determination of molybdenum by inductive couple plasma atomic emission spectroscopy     

H. Sid Kalal Ph.D.  H. Ahmad Panahi Ph.D.  N. Framarzi  E. Moniri Ph.D.  A. Naeemy  H. Hoveidi Ph.D.  A. Abhari 《International Journal of Environmental Science and Technology》2011,8(3):501-512

A chelating resin is prepared by condensation polymerization of aniline with formaldehyde and characterized by Fourier transform infrared spectrometer, elemental analysis and thermogravimetric analysis and studied for the preconcentration and determination of trace Molybdate ion from environmental water sample using inductive couple plasma atomic emission spectroscopy. The optimum pH value for sorption of the metal ion was 5. The sorption capacity of functionalized resin is 3.1 mg/g. The chelating sorbent can be reused for 20 cycles of sorption-desorption without any significant change in sorption capacity. The best desorption of the metal ions from resin was obtained by 0.5 mol/L nitric acid as eluting agent. The profile of molybdenum uptake on this sorbent reflects good accessibility of the chelating sites in the aniline-formaldehyde. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Molybdate ion modified resin were analyzed by five isotherm models such as Langmuir, Freundlich and Temkin. Langmuir isotherm parameters obtained from the four Langmuir linear equations by using linear method. Based on the Langmuir isotherm analysis, the monolayer adsorption capacity was determined to be 4.03 mg/g at 20 °C. The method was applied for molybdenum ions determination from river water sample.  相似文献   

Regional variations in cleavage and fold development in North Wales     

S. D. G. Campbell  A. J. Reedman  M. F. Howells 《Geological Journal》1985,20(1):43-52

The arcuate pattern of the main Caledonian cleavage and associated fold axial plane traces in North Wales is due partly to NW-SE compression with tectonic transport to the southeast against the concealed crop of the Tan y grisiau Microgranite. Low-angle cleavage close to the microgranite is shown to be a local variant of the regional cleavage formed during the main deformation and not an earlier phase as previously supposed. Transcurrent movements along several major fault systems are also related to compression around the microgranite and the Harlech Dome block.  相似文献