Unsteady heat transfer of a monatomic gas between two coaxial circular cylinders
We consider a kinetic-theory treatment of the cylindrical unsteady heat transfer. A model kinetic equation of the BGK (Bhatnager-Gross-Krook) type is solved using the method of moments with a two-sided distribution function. We study the relations between the different macroscopic properties of the gas as the temperature, density, and heat flux with both the radial distance r and the time t. Also we study the problem from the viewpoint of irreversible thermodynamics and estimate the entropy, entropy production, entropy flux, thermodynamic forces, kinetic coefficients, the change in internal energy, and verify Onsager′s relation for nonequilibrium thermodynamic properties of the system.
Thermodynamic Study of Unsteady BGK Model for a Binary Gas Mixture Affected by a Nonlinear Thermal Radiation Field.
In the present study, a development thermodynamic study of the papers (JNET, 2011, 36 (1), 75-98 and Can. J. of Phy., 2012, 90(2): 137-149) is introduced. The non-stationary BGK (Bhatnager- Gross- Krook) model of the kinetic equations for a rarefied gas mixture affected by nonlinear thermal radiation field is solved instead of the stationary equations. The unsteady solution gives the problem a great generality and more applications. The non-equilibrium thermodynamic properties of the system (gas mixture + the heated plate) is investigated. The entropy, entropy flux, entropy production, thermodynamic forces, kinetic coefficients are obtained for the system. The verification of the Boltzmann H-theorem, Le Chatelier principle, second law of thermodynamic and Onsager's reciprocity relation for the system are made. The ratios between the different contributions of the internal energy changes based upon the total derivatives of the extensive parameters are estimated via the Gibbs formula. The results are applied to the Argon-Neon binary gas mixture, for various values of both of molar fraction parameters and radiation field intensity. 3D-Graphics illustrating the calculated variables are drawn to predict their behavior. The results are discussed.
Enumeration of total coliforms, fecal coliforms, and Escherichia coli in foods by hydrophobic grid membrane filter: supplementary report.
Raw, comminuted poultry meat was used to determine the specificity of the media and incubation conditions used in the hydrophobic grid membrane filter method. Confirmation rates for target colonies were 100% for total coliforms, 98% for fecal coliforms, and 97-99% for Escherichia coli. The results of total coliform enumeration in 30 pasteurized milk samples by both the hydrophobic grid membrane filter method and AOAC method 46.013-46.016 are also reported.