pore network modeling uses a network of pores connected by throats to model the void space of a porous medium and tries to predict its various characteristics during multiphase flow of various fluids. in most cases, a non-realistic regular lattice of pores is used to model the characteristics of a porous medium. although some methodologies for extracting geologically realistic irregular network...

mixed clayey soils occur as mixtures of sand (or gravel) and clay in widely varying proportions. their engineering behavior has not been comprehensively studied yet. an experimental program, comprising monotonic, cyclic, and post-cyclic triaxial tests was undertaken on compacted clay-granular material mixtures, having different proportions of clay and sand or gravel. this paper presents the res...

the permeability and tortuosity of pore-scale two and three-dimensional random porous media were calculated using the lattice boltzmann method (lbm). effects of geometrical parameters of medium on permeability and tortuosity were investigated as well. two major models of random porous media were reconstructed by computerized tomography method: randomly distributed rectangular obstacles in a uni...

in this work, a tracer study on pore initiation in anodic alumina in oxalic acid was performed. effects of some experimental parameters such as applied electrical potential, electrolyte composition and heat pretreatment were evaluated. electrochemical and morphological experiments were performed using potentiostatic anodizing and scanning electron microscopy (sem) techniques, respectively. effe...

powder activated carbon surface (ac) was grinded and modified and altered procedure thorough a facile and easy chemical reaction to appearance of 2-((3silylpropylimino)1-methyl) phenol (ac- (spimp)). subsequently, this novel sorbent efficiently applied for the extraction and preconcentration of some metal ions from real samples. preliminary the influences of variables such as ph, amounts of rea...

bamboo-structured carbon nanotubes are grown on co-mo/mcm-41 catalyst in the temperature range of 873-973 k by thermal chemical vapor deposition of acetylene. this study shows that the purified carbon nanotubes have open tips and the metals of the catalyst are not encapsulated. thus, the bamboo-structure seems to grow from the base. pore size distribution of the product is quite narrow and is i...

The productive fusion pore in membrane fusion is generally thought to be toroidally shaped. Theoretical studies and recent experiments suggest that its formation, in some scenarios, may be preceded by an initial pore formed near the rim of the extended hemifusion diaphragm (HD), a rim-pore. This rim-pore is characterized by a nontoroidal shape that changes with size. To determine this shape as ...

Nuclear pore complexes control the exchange of macromolecules between the cytoplasm and the nucleus. A selective permeability barrier that arises from a supramolecular assembly of intrinsically unfolded nucleoporin domains rich in phenylalanine-glycine dipeptides (FG domains) fills the nuclear pore. There is increasing evidence that selective transport requires cohesive FG domain interactions. ...

Compositional analysis of nuclear pore complexes (NPCs) is nearing completion, and efforts are now focused on understanding how these protein machines work. Recent analysis of soluble transport factor interactions with NPC proteins reveals distinct and overlapping pathways for movement between the nucleus and cytoplasm. New fluorescence- and microscopy-based strategies have been used to monitor...

The nuclear pore complex (NPC) regulates the bidirectional movement of cell components across the nuclear envelope. In this issue, D'Angelo et al. (2009) demonstrate that the NPC loses essential protein subunits as cells age, resulting in increased nuclear permeability and potentially contributing to organismal aging.