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...

We report on the fabrication and electrical characterization of functionalized solid-state nanopores in low stress silicon nitride membranes. First, a pore of approximately 50 nm diameter was drilled using a focused ion beam technique, followed by the local deposition of silicon dioxide. A low-energy electron beam induced the decomposition of adsorbed tetraethyl orthosilicate resulting in site-...

Lotus-type porous aluminum with cylindrical pores oriented in one direction was fabricated by a casting method utilizing the decomposition of moisture in a vacuum. Hydrogen decomposed from moisture is utilized for cylindrical pores to grow during unidirectional solidification. However, pores are not formed in the case of a casting in hydrogen or argon atmosphere, because hydrogen or argon gas p...

This study was performed to determine whether the particle size of the starting collagen powder or the material of molds used during freeze-drying had effects on the scaffold pore structure. Collagen particles were separated by size prior to slurry making using a sieve with 1000 um openings, and scaffolds were made using both metal pans and polysulfone trays, two commonly used molds. The mean a...

In this work, a nanoporous template with a controllable channel diameter was used to simulate the oil storage ability of shale pore throats. On the basis of the wetting behaviours at the nanoscale solid-liquid interfaces, the seepage of oil in nano-channels of different diameters was examined to accurately and systematically determine the effect of the pore diameter on the oil storage capacity....

The ‘‘mesopore protection hypothesis’’ [Chem. Geol. 114 (1994) 347; Geochim. Cosmochim. Acta 58 (1994) 1271] proposes that organic matter (OM) may be protected from enzymatic degradation by sequestration within mineral mesopores (2–50 nm diameter). This hypothesis is a leading, though controversial, theory in explaining both the preservation of some extremely labile OM compounds and observed co...

1. Introduction Molecular dynamics under confinement is a subject of extensive scientific research. Besides fundamental interest, the understanding of the very intrinsic mechanisms of how confinements alter the fluid transport properties has an immense impact on application-oriented sciences, including life sciences in particular. Having the possibility of preparing mesoporous materials with we...

Channelrhodopsin-2 (ChR2) is a microbial-type rhodopsin found in the green algae Chlamydomonas reinhardtii. Under physiological conditions, ChR2 is an inwardly rectifying cation channel that permeates a wide range of mono- and divalent cations. Although this protein shares a high sequence homology with other microbial-type rhodopsins, which are ion pumps, ChR2 is an ion channel. A sequence alig...