2,190 research outputs found

    Nondiagonal Graphene Conductivity in the Presence of In-Plane Magnetic Fields

    Get PDF
    We study the electron/hole transport in puddle-disordered and rough graphene samples which are subject to in-plane magnetic fields. Previous treatments, mostly devoted to regimes where the electron/hole scattering wavelengths are larger than the surface height correlation length, are based on the use of transport equations with appropriate forms for the collision term. We point out in this work, as a counterpoint, that classical Lorentz force effects, which are expected to hold when the Fermi level is far enough away from the charge neutral point, can be heuristically assessed through disordered Boltzmann equations that contain magnetic-field dependent material derivatives, and keep the zero magnetic-field structure of the collision term. It turns out that the electric conductivity tensor gets a peculiar nondiagonal component, induced by the in-plane magnetic field that crosses the rough topography of the graphene sheet, even if the projected random transverse magnetic field vanishes in the mean. Numerical estimates of the transverse conductivities suggest that they are suitable of observation under conditions which are within the reach of up-to-date experimental methods.Comment: 14 pages, 2 figure

    Thermal inactivation of Alicyclobacillus acidoterrestris spores in fruit product processing

    Get PDF
    Alicyclobacillus acidoterrestris spores were recently proposed to be used as design criterion for thermal processes of acid fruit products. This microorganism has been found in commercial pasteurized acid fruit juices, such as orange and apple. Although being non-pathogenic and not easy to detect visually, it is responsible for off-flavours development. On the other hand, the first thermal inactivation kinetic studies confirmed that these spores are much more resistant than the usual spoilage microorganisms in acid foods. Therefore, in 2000 it was firstly proposed to be used in the design of hot-filling and continuous pasteurization conditions of a tropical fruit pulp and juice, respectively. This work presents a critical review on inactivation kinetics of Alicyclobacillus acidoterrestris spores. The available studies were obtained under thermal treatments, and studied the effects of temperature, pH and soluble solids. Those effects were quantified in terms of decimal reduction time (first order model) and z-values (Bigelow model). Furthermore, they were obtained under isothermal conditions. Future challenges in this field are to quantify the inactivation kinetics behaviour under dynamic conditions, using thermal and non-thermal treatments, such as ozonation, ultrasonication or high pressure. These alternative treatments have the advantage of minimizing quality attributes degradation and improving products. Moreover, predictive microbiology skills are suggested as a valuable tool for process design and optimization

    Models of microbial inactivation: aplication in foods

    Get PDF

    Schmidt balls around the identity

    Full text link
    Robustness measures as introduced by Vidal and Tarrach [PRA, 59, 141-155] quantify the extent to which entangled states remain entangled under mixing. Analogously, we introduce here the Schmidt robustness and the random Schmidt robustness. The latter notion is closely related to the construction of Schmidt balls around the identity. We analyse the situation for pure states and provide non-trivial upper and lower bounds. Upper bounds to the random Schmidt-2 robustness allow us to construct a particularly simple distillability criterion. We present two conjectures, the first one is related to the radius of inner balls around the identity in the convex set of Schmidt number n-states. We also conjecture a class of optimal Schmidt witnesses for pure states.Comment: 7 pages, 1 figur
    • …
    corecore