نتایج جستجو برای: pore volume

تعداد نتایج: 351639  

Mesoporous nanostructured γ-Al2O3 powders were synthesized through multi- step precipitation procedures using the pH-swing technique. Structural and morphological characteristics in addition to the thermal behavior of the procured samples were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FT-IR) ...

Journal: :international journal of civil engineering 0
faradjollah askari orang farzaneh

although some 3d slope stability algorithms have been proposed in recent three decades, still role of pore pressures in three dimensional slope stability analyses and considering the effects of pore water pressure in 3d slope stability studies needs to be investigated. in this paper, a limit analysis formulation for investigation of role of the pore water pressure in three dimensional slope sta...

2005
Ravindra Deshpande Douglas M. Smith Jeffrey Brinker

A two-step acid/base-catalyzed silica gel has been aged in alcohol and water baths followed by various aprotic solvents with a wide range of surface tensions. Low temperature (CO 2) and high temperature (ethanol) aerogels were also prepared. The physical and chemical structures of gels dried from aprotic solvents were studied by a series of techniques (29Si MAS-NMR, nitrogen adsorption, SAXS, e...

Journal: :Chemosphere 2000
K J Rockne G L Taghon D S Kosson

Soot was harvested from five combustion sources: a dodecane flame, marine and bus diesel engines, a wood stove, and an oil furnace. The soots ranged from 20% to 90% carbon by weight and molar C/H ratios from 1 to 7, the latter suggesting a highly condensed aromatic structure. Total surface areas (by nitrogen adsorption using the Brunauer Emmett Teller, BET method) ranged from 1 to 85 m2 g(-1). ...

Journal: :Chemical communications 2012
David Fairen-Jimenez Yamil J Colón Omar K Farha Youn-Sang Bae Joseph T Hupp Randall Q Snurr

For a series of metal-organic frameworks with rht topology, we study computationally the effect of the linker length on the surface area, pore size, and pore volume, relating them with the hydrogen adsorption properties. The results provide new insights about the excess capacities and the pressures where the uptake maxima in the excess isotherms occur. We found that, of the materials studied, ...

Journal: :تحقیقات آب و خاک ایران 0
امین سلطانی دانشجوی کارشناسی ارشد سازه‏ های آبی گروه مهندسی آبیاری و آبادانی دانشگاه تهران علی رئیسی استبرق دانشیار گروه مهندسی آبیاری و آبادانی دانشگاه تهران جمال عبدالهی مربی گروه مهندسی آبیاری و آبادانی دانشگاه تهران

expansive soils are considered a worldwide problem as they cause extensive damage tocivil engineering structures. an important characteristic of expansive soils is theirsusceptibility to volume change due to the phenomenon of wetting and drying. this paperpresets the effect of pore water quality on the swelling and shrinkage behavior of anexpansive soil during wetting and drying cycles. thirty ...

In this study, Santa Barbara Amorphous (SBA-15) mesoporous silica has been functionalized with aminopropyl groups that were converted to propargyl-bearing moieties through the reaction with propargyl bromide. The material then underwent an efficient Cu(I)-catalyzed azide alkyne click reaction with sodium azide in order to obtain the corresponding triazole products. The covalent modification of ...

Journal: :journal of nanostructures 2012
a. tadjarodi m. sedghi k. bijanzad

mesoporous  mgo  microstructures  were  synthesized  using magnesium  acetate  tetrahydrate,  ammonium  oxalate  monohydrate and  pluronic  f127  via  heating  at  40  °c  for  24  h  and  subsequent calcination. the mesoporous structure of magnesium oxide with the specific  surface  area  of  47m2/g,  pore  volume  0.30  cm3/g  and  the average pore size 24 nm is produced. according to xrd stu...

In this research effect of synthesis method of magnesium aluminate as support of Ni catalysts at the reverse water gas shift (RWGS) reaction was evaluated. The RWGS reaction is applied in Carbon Dioxide Hydrogenation to Form Methanol via a Reverse Water-Gas Shift Reaction (CAMERE) process for the transformation of CO2 into methanol. The MgAl2O4 supports were prepared by sol-gel (M1), surfactant...

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