Multi-scale

As a practice-based subject, the formation and development of tribology have always been associated with the requirement from society and technology development. Tribology experienced several different stages in its history. Its developing process indicates an obvious trend of integration and combination of multi-scientific subjects in a multi-scale nature from macroscopic dimension to nanometre. 

Chandrasekhar, S, Liquid Crystals, 2nd ed. Cambridge University Press Cambridge, 1992. Chang, H-C, Multi-Scale Analysis of Effective Transport in Periodic Heterogeneous Media, Chemical Engineering Communications 15, 83, 1982. 

Crampin EJ, Smith NP, Hunter PJ. Multi-scale modelling and the lUPS physiome project. J Mol Histol 2004 35 707-14. 

Multi-scale modeling problems in heterogeneously catalyzed a-olefin polymerization... 

Feature Extraction (Multi-Scale Representation of Trends) s(x,) Inductive Learmng... 

Bakshi, B. R., and Stephanopoulos, G., Representation of process trends. Part III. Multi-scale extraction of trends from process data. Comput. Chem. Eng. 18, 267 (1994a). 

Witkin, A. P., Scale space filtering A new approach to multi-scale description. In Image Understanding (S. Ullman and W. Richard, eds.), pp. 79-95. Ablex, Norwood, NJ, 1983. 

Hessel and Lowe report on hybrid, i.e. multi-scale, approaches which are currently most often favored for micro-reactor plant construction, simply for practical time and cost reasons [9, 10]. In addition, such an approach allows one to fit micro reactors in existing industrial, producing and academia, measuring environments. The micro reactor is only used where it is really needed and costs for changing the processing are kept to a minimum in such a way (Figure 1.9). 

Figure 1.9 Hybrid, multi-scale micro-reactor plant for catalyst testing for propane steam reforming [15],...

The integration of sensing and other functions in a micro-flow system requires either monolithic, on-chip or hybrid, multi-scale approaches. Concerning the latter, Hessel and Lowe discuss the lack of compatibility of today s fluidic interfaces and report on a German project team developing a standard for micro-reactor interconnection [9, 10]. 

Monolith vs. Hybrid/Multi-scale Specialty vs. Multi-purpose ... 

The realization of complete bench-scale micro reactor set-ups is certainly still in its infancy. Nevertheless, the first investigations and proposals point at different generic concepts. First, this stems from the choice of the constructing elements for such set-ups. Either microfluidic components can be exclusively employed (the so-caUed monolithic concept) or mixed with conventional components (the so-called hybrid or multi-scale concept). Secondly, differences concerning the task of a micro-reactor plant exist. The design can be tailor-made for a specific reaction or process (specialty plant) or be designated for various processing tasks (multi-purpose plant). 

This class of hybrid components comprises chip micro-reactor devices, as described in Section 4.1.3, connected to conventional tubing. This may be H PLC tubing which sometimes has as small internals as micro channels themselves. The main function of the tubing is to provide longer residence times. Sometimes, flow through the tube produces characteristic flow patterns such as in slug-flow tube reactors. Chip-tube micro reactors are typical examples of multi-scale architecture (assembly of components of hybrid origin). 

Compared with the multi-scale micro mixer-tube concept (see Section 4.1.6), the total-system approach is a true mono-scale solution, and may be even termed monolithic. Integration of sensing and controlling is facile owing to the high order and repetition of construction imits (plates). 

Some of the complications involved in multi-scale porosities and evolutionary paths within fractured rock systems have been explored. For example, in the Palmottu site of gneisses in Finland U, as well as Th, was found to be redistributed into fracture coatings of carbonates and Fe oxides (Suksi et al. 1991). Suksi and Rasilainen (1996) have demonstrated how U concentrated in these fracture fillings can implant daughters in the surrounding phases, generating large fractionations between and Th/ U. 

D.M. York and T.-S. Lee (eds.), Multi-scale Quantum Models for Biocatalysis, 21-55. 

One of the authors (ML) is grateful to Fukui Institute for Fundamental Chemistry, Kyoto University for a Fukui Institute Fellowship. The present work was in part supported by a CREST (Core Research for Evolutional Science and Technology) grant in the Area of High Performance Computing for Multi-scale and Multi-physics Phenomena from the Japan Science and Technology Agency (JST). 

MULTI-SCALE QM/MM METHODS WITH SELF-CONSISTENT-CHARGE DENSITY-FUNCTIONAL-TIGHT-BINDING (SCC-DFTB)... 

In the following, we first briefly review the SCC-DFTB method and comment on a few issues related to the implementation of SCC-DFTB/MM, such as the multi-scale SCC-DFTB/MM-GSBP protocol. Next, a few specific examples of SCC-DFTB/MM simulations are given. The basic motivation is to highlight a number of issues that might impact either the quantitative or even qualitative nature of the result. We hope that the chapter is particularly instructive to researchers who are relatively new to the field and able to help them carry out meaningful QM/MM simulations. 

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