... (2002) “Molecular-Based Microfluidic Simulation Models,” in Handbook of MEMS, 1st ed., M. Gad- el- Hak, ed., CRC press, Boca Raton.Bird, G.A. (1994) Molecular Gas Dynamics and the Direct Simulation ... on the molecular distribution function of the surrounding gas, the ther-mophoretic force can be calculated by integrating the momentum flux imparted by the molecules strik-ing the particle. The ... characteris-tic of small scale devices (Pe Ͻ 1), the Nusselt number defined byNuTϭ (7. 20)q2Hᎏᎏκ(TwϪ Tb) 7- 1 4 MEMS: Introduction and Fundamentals 5 The dependence on the flow field comes from...