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131.
Dissolution and Seepage Coupling Effect on Transport and Mechanical Properties of Glauberite Salt Rock 总被引:1,自引:0,他引:1
Weiguo Liang Yangsheng Zhao Suguo Xu Maurice B. Dusseault 《Transport in Porous Media》2008,74(2):185-199
Potential high rates of aqueous dissolution are characteristic of salt rocks, and solute and mass flux through a soluble porous
medium are functions of solute concentration gradients and pressure gradients. Due to different dissolution properties for
different mineral components in glauberite salt rock, an interaction between mineral dissolution and solvent seepage arises,
driven by the hydraulic pressure gradient in the rock. The originally almost impermeable glauberite rock becomes an increasingly
permeable porous medium with dissolution, changing the transport and mechanical properties because of the progressive removal
of solid sodium sulfate (Na2SO4), one of the constitutive components of glauberite salt rock. Glauberite is often found in bedded salt rock deposits, and
the mineral glauberite has economic value and has been mined for many years in China. More economic and safe technologies,
such as controlled solution mining, are inherently attractive. Thus, investigations into relevant physical and mechanical
properties of glauberite in the context of solution mining have value, and to clarify glauberite behaviour, a series of experiments
were performed. It is observed through experiments that the permeability of the rock mass during dissolution of glauberite
is a function of the dissolution duration and the hydraulic pressure gradient applied to the system. For example, in laboratory
tests, after 49, 53 and 70 h of dissolution, the relationships between permeability (k—cm2) and pressure gradient (Δp—MPa across the specimen of length 100 mm) of the glauberite specimens were observed to be k = 0.24 for a Δp of 0.10, k = 0.30 for a Δp of 0.12, and k = 0.41 for a Δp of 0.18, with the empirical functional relationship becoming gradually steeper with pressure. Also, the triaxial compression
(mechanical) characteristics of glauberite salt rock change substantially after a period of dissolution: the compressive strength
under a confining stress of σ3 = 2.0 MPa changes initially from 46 to 11 MPa after 70 h of dissolution and seepage. Along with strength degradation, the
Young’s modulus (stiffness) changed from 4.6 to 0.5 GPa. Evidently, coupled dissolution and seepage rate greatly impact both
transport and mechanical properties of the rock as fabric evolves in a time-dependent manner. 相似文献
132.
Gerd Finke Pierre Lemaire Jean-Marie Proth Maurice Queyranne 《European Journal of Operational Research》2009,199(3):702-705
In this paper, we present a new objective function for scheduling on parallel machines: minimizing the number of machines for schedules of minimum length. We study its complexity and we prove the NP-completeness of this problem, even if there is no precedences or for unitary execution times. We propose several polynomial algorithms for various particular cases. 相似文献
133.
134.
New 4-aminoquinolines having a -CF2CH-(heteroaryl)-OH moiety are obtained in moderate yields from the electrochemical catalyzed reaction of the corresponding 4-amino-3-chlorodifluoroacetyl-2-methoxyquinoline in the presence of heteroaryl aldehydes. A one-pot intramolecular zinc mediated aromatic nucleophilic substitution also gave access to novel difluorinated 5-aminodihydropyrano[2,3-b]quinolin-4-ones. 相似文献
135.
136.
Results in Mathematics - 相似文献
137.
Maurice François 《Fresenius' Journal of Analytical Chemistry》1909,48(4-5):317-318
Ohne Zusammenfassung 相似文献
138.
Frontispiece: Combined Spectroscopic and Electrochemical Detection of a NiI⋅⋅⋅HN Bonding Interaction with Relevance to Electrocatalytic H2 Production 下载免费PDF全文
139.
Mathematical Programming - Switching machines on and off is an important aspect of unit commitment problems and production planning problems, among others. Here we study tight mixed integer... 相似文献
140.
Claude Laflamme Maurice Pouzet Norbert Sauer 《Abhandlungen aus dem Mathematischen Seminar der Universit?t Hamburg》2017,87(2):369-408
A tree is scattered if it does not contain a subdivision of the complete binary tree as a subtree. We show that every scattered tree contains a vertex, an edge, or a set of at most two ends preserved by every embedding of T. This extends results of Halin, Polat and Sabidussi. Calling two trees equimorphic if each embeds in the other, we then prove that either every tree that is equimorphic to a scattered tree T is isomorphic to T, or there are infinitely many pairwise non-isomorphic trees which are equimorphic to T. This proves the tree alternative conjecture of Bonato and Tardif for scattered trees, and a conjecture of Tyomkyn for locally finite scattered trees. 相似文献