A genetic algorithm is used to optimize the modified benzene alkylation process. Based on the previous studies, the modified process increases ethylbenzene selectivity and decreases energy consumption at the same time. The inlet ethylene flow rate of each alkylation reactor is optimized in order to reduce the chance of transalkylation reactions but increase ethylbenzene selectivity. The byprodu...

In the present study, mixed convection laminar flow around an adiabatic body in a Lid-driven enclosure filled with nanofluid using variable thermal conductivity and variable viscosity is numerically investigated. The fluid around the body in the enclosure is a water- based nanofluid containing Al2O3 nanoparticles. The Vertical enclosure’s walls are maintained at constant cold temperature an...

Recent developments of the ac-calorimetric technique adapted for the needs of high pressure experiments are discussed. A semi-quantitative measurement of the specific heat with a Bridgman-type of pressure cell as well as a diamond anvil cell is possible in the temperature range 0.1 K< T < 10 K. The pressure transmitting medium used to ensure good pressure conditions determines to a great extent...

The region of the second ionization of helium in the Sun is a narrow layer near the surface. Ionization induces a local change of the adiabatic exponent Γ1, which produces a characteristic signature in the frequencies of p-modes. By adapting the method developed by Monteiro, Christensen-Dalsgaard & Thompson (1994), we propose a methodology for determining the properties of this region by studyi...

The observation of non-classical correlations arising in two weakly coupled Bose–Einstein condensates was recently reported by Estève et al (2008 Nature 455 1216). In order to observe relative number fluctuations between the two condensates below the standard quantum limit, they utilized the process of ‘adiabatic passage’ to drive the system out of thermal equilibrium. They found that this redu...

We discuss theoretically and demonstrate experimentally the robustness of the adiabatic sum frequency conversion method. This technique, borrowed from an analogous scheme of robust population transfer in atomic physics and nuclear magnetic resonance, enables the achievement of nearly full frequency conversion in a sum frequency generation process for a bandwidth up to two orders of magnitude wi...

The controversial problem of the evolution of an isolated system with an internal adiabatic wall is investigated with the use of a simple microscopic model and the Boltzmann equation. In the case of two infinite volume onedimensional ideal fluids separated by a piston whose mass is equal to the mass of the fluid particles we obtain a rigorous explicit stationary non-equilibrium solution of the ...

Geometric spin frustration in low-dimensional materials, such as the two-dimensional kagome or triangular antiferromagnetic nets, can significantly enhance the change of the magnetic entropy and adiabatic temperature following a change in the applied magnetic field, that is, the magnetocaloric effect. In principle, an equivalent outcome should also be observable in certain high-symmetry zero-di...

Interesting spin Hamiltonians can be realized with ultracold atoms in a two-component Mott insulator (2CMI) [Adv. Phys. 56, 243 (2007); Rev. Mod. Phys. 80, 885 (2008)]. It was recently demonstrated that the application of a magnetic field gradient to the 2CMI enables new techniques of thermometry [Phys. Rev. Lett. 103, 245301 (2009)] and adiabatic cooling [e-print arXiv:1006.4674]. Here we pres...