The effect of pore surface roughness on Knudsen diffusion in nanoporous media is investigated by dynamic Monte-Carlo simulations and analytical calculations. A conceptual difference is found between the roughness dependence of the macroscopic, transport diffusivity and the microscopic, selfdiffusivity, which is reminiscent of diffusion in zeolites, where a similar difference arises due to adsor...

N-Methyl-Nʹ-propyltrimethoxysillylimidazolium chloride was prepared as ionic liquid (IL) containing silylating agent and then used for modification of the internal surface of SBA-15 to gain a heterogeneous ionic liquid catalyst. Subsequently, the obtained SBA-IL was characterized using various techniques, including SEM and TEM images, FT-IR, X-ray diffraction, TGA/DTA and BET ...

We performed steered molecular dynamics (SMD) and umbrella sampling simulations of Cl- ion migration through the transmembrane domain of a prototypical E. coli CLC Cl-/H+ antiporter by employing combined quantum-mechanical (QM) and molecular-mechanical (MM) calculations. The SMD simulations revealed interesting conformational changes of the protein. While no large-amplitude motions of the prote...

The critical Rayleigh number for convective flow of pore water through a permeable spherical body is derived. The result affords constraints on carbonaceous chondrite planetesimal sizes and rates of heat production. If the chemical compositions of carbonaceous chondrites are taken as evidence against flow of pore water, then the present calculations suggest that the parent bodies were less than...

The mesoporous carbon (CMK-3) functionalized with ethylenediamine (EDA) has been synthesized (CMK-3-EDA) and applied as a new mesoporous adsorbent for removal of Cu(II) and Pb(II) cations from aqueous solutions. Nitrogen adsorption–desorption measurements (BET) show that surface area, pore size and pore volume of CMK-3 were significantly changed after amine modification. The BET surface area an...

A new fast pruning algorithm is proposed for computing the IV, lowest frequency components of a Iength-~V discrete cosine transform, where AVO is any integer less than or equal to N, and AV = 2“‘. The computational complexity of the developed algorithm is lower than any of the existing algorithms, resulting in significant time savings. In the special case that AVO = 2 “ Q , the required number ...

In the Bulgarian Black Sea shelf, several gas fields have been discovered in Maastrichtian–Paleocene sediments to date. this study, amplitude versus offset analysis (AVO) was carried out, and extended elastic impedance (EEI) also used, predict fluid lithology properties. Thus, these special cases, AVO (or reflection angle) can significantly de-risk existing Paleocene prospects allow focus on Mi...

in this paper,the molecular geometry for three tautomers of uracil and four tautomers of cytosine has been analyzed. vibrational ir spectra of the tautomers were   investigated at hf and b3lyp level using the ab initio 6-31g* and lanl2dz basis sets from the program package gaussian 98 (a.7 public domain version). the physico-chemical and biochemical properties of uracil and cytosine are one of...