On the kinematics of 2+1-dimensional motions of a fibre-reinforced fluid. Integrable connections

Evolution of foliations of the plane is shown, under a conditionof constant divergence, to be linked to the scattering problemfor the integrable modified Korteweg–de Vries hierarchy.This result is applied to a set of kinematic relations whicharise in the theory of ideal fibre-reinforced fluids. In particular,it is established that the fibres, which are convected withthe fluid, constitute generalized tractrices.     

Evaluation of a valveless thermal desorption system for organic aerosols and vapors. Transfer lines and preconcentration module

Semivolatile organic compounds (SVOCs) are distributed in the atmosphere between the gas- and aerosol-phases. The low vapor pressures of some SVOCs makes thermal extraction and transfer through gas chromatographic (GC) systems difficult. We evaluated a programmable temperature vaporization (PTV) GC inlet, which served as the preconcentration module, and four open-tubular capillaries (Silcosteel- and Siltek-treated stainless steel, Silcosteel-treated stainless steel coated with 100% dimethylpolysiloxane, and deactivated fused silica) as transfer lines in a valveless, whole-sample analytic system. Thermal extraction of C(9)-C(36)n-alkanes at 300 and 320 degrees C from fused silica and quartz wool in the PTV inlet was equally efficient. Adsorptive losses of C(22)-C(36)n-alkanes to stainless steel surfaces that protruded into the PTV inlet were suspected. Thus, treatment of the outer surfaces of transfer lines is recommended for effective thermal transfer of SVOCs. Transfer efficiencies began to decline after n-C(24), n-C(28), and n-C(30) in Silcosteel-treated stainless steel, deactivated fused silica, and Siltek-treated stainless steel transfer lines, respectively. Thus, quantitative recovery at 320 degrees C of compounds with vapor pressures less than about 3 x 10(-8)Pa is not expected in valveless SVOC thermal desorption systems that use Siltek-treated stainless steel transfer lines and fused silica or quartz wool as preconcentration substrates.