A new method has been used to obtain pore size characteristics of MCM-41 catalyst supports and vanadiumsubstituted MCM-41 catalysts. The approach is based on the nonlocal density functional theory (NLDFT) model for nitrogen and argon adsorption in MCM-41, proposed recently. Samples with pore sizes varying from ca. 25 to 37 Å were prepared by hydrothermal synthesis. Two synthesis procedures empl...

Porous alumina ceramics with different porosities were prepared via atmospheric pressure sintering using a sacrificial template method powder as the raw material and carbon fiber (CF) graphite pore-forming agents. The effects of contents ratios agents aspect CF on microstructure, mechanical properties, pore size, pore-size distribution porous samples investigated. In addition, surface fractal d...

This study focused on phase separation of activated sludge mixed liquor by flat-sheet membranes of polytetrafluoroethylene (PTFE). A 20 liter working volume lab-scale MBR incorporating immersed PTFE flat-sheet membrane modules with different pore sizes (0.3, 0.5 and 1.0 μm) was operated for 19 days treating a synthetic wastewater. The experiment was interrupted twice at days 5 and 13 when the m...

M. E. Zeynali [email protected] Petrochemical Synthesis Group, Petrochemical Faculty, Iran Polymer and Petrochemical Institute (IPPI), P. O. Box: 14965/115, Tehran, Iran, Abstract In this study the diffusion coefficients for reaction components were determined for unimodal and bimodal pore size distribution and assuming transitional diffusion regime using a more realistic, Stewart-Johnson, m...

Underground rocks usually have complex pore system with a variety of pore types and a wide range of pore size. The effects of pore structure on elastic wave attenuation cannot be neglected. We investigated the pore structure effects on P-wave scattering attenuation in dry rocks by pore-scale modeling based on the wave theory and the similarity principle. Our modeling results indicate that pore ...

Hydrate phase equilibria for the binary CO2+water and CH4+water mixtures in silica gel pore of nominal diameters 6, 30, and 100 nm were measured and compared with the calculated results based on van der Waals and Platteeuw model. At a specific temperature, three-phase hydrate-water-vapor (HLV) equilibrium curves for pore hydrates were shifted to the higher-pressure condition depending on pore s...

Poly(propylene fumarate) (PPF) is an injectable, biodegradable polymer that has been used for fabricating preformed scaffolds in tissue engineering applications because of in situ crosslinking characteristics. Aiming for understanding the effects of pore structure parameters on bone tissue ingrowth, 3-dimensional (3D) PPF scaffolds with controlled pore architecture have been produced in this st...

Bi2Mn2O7 nano-powders were synthesized via a stoichiometric 1:1 Bi:Mn molar ratio hydrothermal method at 180 °C for 48 h in a 1M NaOH aqueous solution; and solid state method, using Bi(NO3)3.5H2O and MnO2 as raw materials. The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique. Also, the rietveld analysis was done in FullProf in profile matching mode. It was f...

Background. Averaged Norbeck Social Support Questionnaire (NSSQ) support scores remove the influence of network size variability but may unduly lower scores for participants with large networks. Objectives. To evaluate the use of averaged NSSQ scores. Method. Pearson correlations determined if averaged scores decreased as network size increased across three samples. Then, Pearson correlations b...

Three kinds of N-doped mesoporous TiO₂ hollow spheres with different N-doping contents, surface area, and pore size distributions were prepared based on a sol-gel synthesis and combined with a calcination process. Melamine formaldehyde (MF) microspheres have been used as sacrificial template and cetyltrimethyl ammonium bromide (CTAB) or polyvinylpyrrolidone (PVP) was selected as pore-directing ...