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排序方式: 共有118条查询结果,搜索用时 15 毫秒
1.
Xiaoyan Liu Karen L. Feilberg Wei Yan Erling H. Stenby 《Journal of Dispersion Science and Technology》2013,34(11):1611-1617
AbstractIn this study, the atomic force microscopy colloidal probe technique was employed to investigate the interaction between apolar, basic and acidic model oil probes and a calcite surface in solutions containing different concentrations of NaCl, CaCl2 and Na2SO4. In the presence of SO42?, hydration and structural forces were observed between apolar model oil probes and a calcite surface on approach. Relatively low adhesion forces were observed between the basic model oil probes and the calcite surface, while higher adhesion forces were observed between the acidic model oil probes and the calcite surface. Furthermore, the adhesion forces between the basic model oil probes and the calcite surface significantly increased in the presence of SO42?, while the adhesion force between the acidic model oil probes and the calcite surface decreased in the presence of Ca2+ or SO42?. The differences in the adhesion forces are related to electrostatic attraction and ion bridging forces between the model oil probes and the calcite surface. 相似文献
2.
Geertsma’s analytical method is often used to compute strain and stress changes around a compacting geological reservoir. The present work extends Geertsma’s solution by adding a rigid layer beneath the compacting reservoir. Analytical formulae are presented for all the components of displacement of a point in the subsurface. Our derivation includes the correction of an error found in the paper written by Sharma in 1956. 相似文献
3.
The extended UNIQUAC model [K. Thomsen, P. Rasmussen, Chem. Eng. Sci. 54 (1999) 1787–1802] was applied to the thermodynamic representation of carbon dioxide absorption in aqueous monoethanolamine (MEA), methyldiethanolamine (MDEA) and varied strength mixtures of the two alkanolamines (MEA–MDEA). For these systems, altogether 13 interaction model parameters are adjusted. Out of these parameters, 11 are temperature dependent. 相似文献
4.
5.
Abstract Infrared spectra of codeposited ethyl benzoate with excess titanium tetrachloride at 80 K revealed a novel 2:1 complex, where the inorganic entity is proposed to be a dimeric, triple bridged titanium tetrachloride unit. The ester is complexed to one of the octahedral titanium units through the carbonyl group. Compared to the 2:2 complex there are νc=o' ν α-C-Oand νTi-O shifts of -40/-47, +4/+24 and +16/17 cm?1, depending on which of the 18O-carbonyl or d5-ethyl isotopic congeners is considered. 相似文献
6.
We present a dynamic pore-scale network model of imbibition, capable of calculating residual oil saturation for any given capillary number, viscosity ratio, contact angle, and aspect ratio. Our goal is not to predict the outcome of core floods, but rather to perform a sensitivity analysis of the above-mentioned parameters, except from the viscosity ratio. We find that contact angle, aspect ratio, and capillary number all have a significant influence on the competition between piston-like advance, leading to high recovery, and snap-off, causing oil entrapment. Due to significant CPU-time requirements we did not incorporate long-range correlations among pore and throat sizes in our network, but were limited to small-range correlations. Consequently, the gradual suppression of snap-off occurs within one order of magnitude of the capillary number. At capillary numbers around 108 - 107 snap-off has been entirely inhibited, in agreement with results obtained by Blunt (1997) who used a quasi-static model. For higher aspect ratios, the effect of rate and contact angle is more pronounced. 相似文献
7.
Dirk-Uwe Astrath Florian Lottes Duc Thoung Vu Wolfgang Arlt Erling H. Stenby 《Adsorption》2007,13(1):9-19
The efficiency of packed chromatographic columns was investigated experimentally by means of computed tomography (CT) techniques.
The measurements were carried out by monitoring tracer fronts in situ inside the chromatographic columns. The experimental
results were fitted using the equilibrium dispersive model (EDM) and varying the so called apparent axial dispersion coefficient.
The additivity of the first and second central moments was exploited to estimate column efficiency in different regions of
the column.
The results showed that the columns under investigation offered a higher column efficiency in the centre compared to the wall
region. Furthermore the void fraction in the vicinity of the walls was lower than that in the column core. For this reason
the bands were conveyed faster in the central region of the column where the permeability was higher. This result is in good
agreement with earlier findings. 相似文献
8.
Let T be a free ergodic measure-preserving action of an abelian group G on (X,μ). The crossed product algebra RT=L∞(X,μ)? G has two distinguished masas, the image CT of L∞(X,μ) and the algebra ST generated by the image of G. We conjecture that conjugacy of the singular masas ST(1) and ST(2) for weakly mixing actions T(1) and T(2) of different groups implies that the groups are isomorphic and the actions are conjugate with respect to this isomorphism. Our main result supporting this conjecture is that the conclusion is true under the additional assumption that the isomorphism γ : RT(1)→RT(2) such that γ(ST(1))=ST(2) has the property that the Cartan subalgebras γ(CT(1)) and CT(2) of RT(2) are inner conjugate. We discuss a stronger conjecture about the structure of the automorphism group Aut(RT,ST), and a weaker one about entropy as a conjugacy invariant. We study also the Pukanszky and some related invariants of ST, and show that they have a simple interpretation in terms of the spectral theory of the action T. It follows that essentially all values of the Pukanszky invariant are realized by the masas ST, and there exist non-conjugate singular masas with the same Pukanszky invariant. 相似文献
9.
We present solubility and diffusion data for the gases methane and carbon dioxide in the polymer poly(vinylidene fluoride). The polymer was cut from extruded piping intended for use in offshore oil and gas applications. Measurements were carried out using a purpose-built high-pressure microbalance. These properties were determined in the temperature range 80-120 °C and in the pressure range 50-150 bar for methane and 20-40 bar for carbon dioxide. In general, good agreement was obtained for similar measurements reported in the literature. Solubility follows a Henry’s law (linear) dependence with pressure. Diffusion coefficients for each of the gases in the polymer were also measured using the balance. Activation energies for diffusion and heats of solution for the two gases in the polymer were also determined. 相似文献
10.
令X=(n1,n2,…,nt),Y=(m1,m2,…,mt)是两个t维递减序列.如果对所有的j,1≤j≤t,都有∑i=1~j、ni≥∑i=1~j mi以及∑i=1~t ni=∑i=1~t mi,则称X可盖Y,记作X■Y.如果X≠Y,则记作X■Y.本文考虑联图G(n1,n2,…,nt;a)=(Kn1∪n2∪…∪Knt)∨Ka的谱半径,这里n1+n2+…+nt+a=n,(n1,n 相似文献