Nanoporous medium

This implies that in parallel laboratory experiments the exchange of matter between the confined fluid and a bulk reservoir is insignificant or that a bulk phase in the sense of the SFA experiment (see Section 5.3.1) riiiiy not even be present at all. Such a situation is realized, for example, in the SANS experiments described in Section 4.8.1 where a binary fluid mixture is confined to a nanoporous medium (i.e., pellets) without being in contact with a bulk reservoir. 

The dynamics of a heterogeneously catalyzed gas-phase reaction occurring in a nanoporous medium in combination with heat and mass transfer was simulated using a finite-volume approach. In contrast to other studies of similar type, heat and mass transfer in the nanoporous medium was explicitly accounted for by solving volume-averaged transport equations in the porous medium. Such an approach made it possible to compare the transport resistances in the gas phase and in the porous medium and to study the tradeoff between maximization of... 

Basically, the nanoporous water-filled medium with chargeable metal walls works like a tunable proton conductor. It could be thought of as a nanoprotonic transistor. In such a device, a nanoporous metal foam is sandwiched between two PEM slabs, acting as proton source (emitter) or sink (collector). The bias potential applied to the metal phase controls proton concentration and proton transmissive properties of the nanoporous medium. The value of cp needed to create a certain proton flux depends on surface charging properties and porous structure of the medium. Moreover, coating pore walls with an electroactive material, for example, Pt, would transform it from a tunable proton conductor into a catalytic layer with proton sinks at the interface. Owing to the intrinsically small reaction rate of the ORR, it would not significantly affect the proton transport properties. 

Hence, the mode only experiences the nanoporous silica, the film, and the cover medium resulting in a pure monomode operation. 

By altering the cover medium between pure water and a water-glycerol solution (corresponding to RIs of 1.331 and 1.355, respectively), the TE and TM peaks shift according to Fig. 15. It is seen that compared with the data obtained with a commercial waveguide chip the nanoporous waveguide has... 

In the past, the principles described have been implicitly recognized in several attempts to convert monolithic catalysts into catalytic heat exchangers. While the use of millimeter dimensions and nanoporous ceramic supports meets the primary criteria already mentioned, the parallel channel structure of monoliths is not ideally tailored for heat exchanger applications, and complex header structures are required to uniformly distribute and collect reaction medium and coolant to and from the individual channels (Figure 9). The unsatisfactory interface between the milli- and macroscale has been a major weakness of such concepts. 

Reversible hydrogen electrosorption is another kind of pseudofaradic effect which might be also observed with nanoporous carbons in aqueous medium. In this case, nascent hydrogen formed by water reduction under negative polarization of carbon is adsorbed in the material reversal of polarization provokes its desorption by oxidation [39],... 

Ferrari and co-workers examined the feasibility of using microfabiicated silicon nanochannels for immunoisolation. A suspension of cells was placed between two microfabricated structures with nanopor-ous membranes to fabricate an immunoisolation biocapsule. Characterization of diffusion through the nanoporous membranes demonstrated that 18nm channels did not completely block IgG but did provide adequate immunoprotection (immunoprotected cells remained functional in vitro in a medium containing immune factors for more than two weeks, while unprotected cells ceased to function within two days). A major application of biocapsules containing nanochannels is immunoisolation of transplanted cells for the treatment of hormonal and biochemical deficiency diseases, such as diabetes. 

Fig. 2 Total-internal reflection (TIR) based waveguides, (a) TIR principle of ray propagating in core medium with index c. surrounded by cladding with index nci. (b) LCWG, (c) nanoporous cladding waveguide, (d) liquid-liquid (L ) waveguide, (e) slot waveguide...

The mechanism of electrochemical hydrogen storage in a nanoporous activated carbon should be taken into account in order to detect the possible optimizations of this process. The electrochemical hydrogen capacity of carbons depends on various parameters such as their physicochemical properties, the nature of the electrolytic medium and its concentration, the potential cut-off. Taking into accoxmt the results under gas pressure [117,118], the carbon sample should contain a noticeable amount of ultramicropores (<0.7 nm) [76], which should be highly efficient for hydrogen sorption. 

Furthermore, this smectic nanoporous network could be used as reaction medium, for instance for the formation of silver nanoparticles (NPs) [78]. The pores were first filled with silver ions and subsequently the ions were reduced to form Ag nanoparticles. The NPs are monodisperse (Fig. 2.20) [78], and interestingly, the size... 

Beguin, F, M. Friebe, K. Jurewicz, C. Vix-Guterl, J. Dentzer, and E. Frackowiak. 2006. State of hydrogen electrochemically stored using nanoporous carbons as negative electrode materials in an aqueous medium. Carbon 44 2392-2398. 

Besides the investigation of monolithic carbons with well-ordered mesoporosity as CO2 sorbents, the synthesis of ordered mesoporous carbon films for CO2 capture (membrane gas separation) also attracts much interest. Noticeably, highly ordered mesoporous carbon with cubic Im3m symmetry has been synthesized successfully via a direct carbonization of self-assembled F108 (EOi32P05oEOi32) and RE composites obtained in a basic medium of non-aqueous solution [66]. Dai et al. [49] demonstrated a stepwise self-assembly approach to the preparation of large-scale, highly ordered nanoporous carbon films (Eig. 2.14). 

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