Separation of suspended particles by arrays of obstacles in microfluidic devices

The stochastic transport of suspended particles through a periodic pattern of obstacles in microfluidic devices is investigated by means of the Fokker-Planck equation. Asymmetric arrays of obstacles have been shown to induce the continuous separation of DNA molecules of different length. The analysis presented here of the asymptotic distribution of particles in a unit cell of these systems shows that separation is only possible in the presence of a driving force with a non-vanishing normal component at the surface of the solid obstacles. In addition, vector separation, in which different species move, in average, in different directions within the device, is driven by differences on the force acting on the various particles and not by differences in the diffusion coefficient. Monte-Carlo simulations performed for different particles and force fields agree with the numerical solutions of the Fokker-Planck equation in the periodic system

Thermal rectifier from deformed carbon nanohorns

We study thermal rectification in single-walled carbon nanohorns (SWNHs) by using non-equilibrium molecular dynamics (MD) method. It is found that the horns with the bigger top angles show larger asymmetric heat transport due to the larger structural gradient distribution. This kind of gradient behavior can be further adjusted by applying external strain on the SWNHs. After being carefully elongated along the axial direction, the thermal rectification in the elongated SWNHs can become more obvious than that in undeformed ones. The maximum rectification efficiency of SWNHs is much bigger than that of carbon nanotube intramolecular junctions.Comment: 3 figure

State Cybercrime Legislation in the United States of America: A Survey

In the United States, cybercrimes are the focus of legislation adopted at both the state and federal levels. The U.S. Constitution allocates lawmaking authority between the two levels according to certain principles, one of which is that even when federal jurisdiction to legislate exists, federal legislation is appropriate only when federal intervention is required. And while federal legislative authority can pre-empt the states\u27 ability to legislate in a given area, it rarely does, so it is not unusual for federal criminal laws to overlap with state prohibitions that address essentially the same issues