Dissipative Transport: Thermal Contacts and Tunnelling Junctions

The general theory of simple transport processes between quantum mechanical reservoirs is reviewed and extended. We focus on thermoelectric phenomena, involving exchange of energy and particles. The theory is illustrated on the example of two reservoirs of free fermions coupled through a local interaction. We construct a stationary state and determine energy and particle currents with the help of a convergent perturbation series. We explicitly calculate several interesting quantities to lowest order, such as the entropy production rate, the resistance, and the heat conductivity. Convergence of the perturbation series allows us to prove that they are strictly positive under suitable smallness and regularity assumptions on the interaction between the reservoirs. Communicated by Gian Michele Graf submitted 15/01/03, accepted: 25/02/03     

Essay: A New Era in High-Energy Physics

In TeV-scale gravity, scattering of particles with center-of-mass energy of the order of a few TeV can lead to the creation of nonperturbative, extended, higher-dimensional gravitational objects: Branes. Neutral or charged, spinning or spinless, Einsteinian or supersymmetric, low-energy branes could dramatically change our picture of high-energy physics. Will we create branes in future particle colliders, observe them from ultra high energy cosmic rays, and discover them to be dark matter?     

Zero Viscosity Limit for Analytic Solutions, of the Navier-Stokes Equation on a Half-Space.¶I. Existence for Euler and Prandtl Equations

This is the first of two papers on the zero-viscosity limit for the incompressible Navier-Stokes equations in a half-space. In this paper we prove short time existence theorems for the Euler and Prandtl equations with analytic initial data in either two or three spatial dimensions. The main technical tool in this analysis is the abstract Cauchy-Kowalewski theorem. For the Euler equations, the projection method is used in the primitive variables, to which the Cauchy-Kowalewski theorem is directly applicable. For the Prandtl equations, Cauchy-Kowalewski is applicable once the diffusion operator in the vertical direction is inverted. Received: 5 September 1995 / Accepted: 14 July 1997     

Choice of the Focal Point Position Using Lasentec FBRM

The Focused Beam Reflectance Measurement (FBRM) technique provides on‐line and in situ information about the chord length distribution (CLD) of a population of particles in dispersion. The effect of changing the focal point position on the measured CLD is experimentally analyzed by carrying out single particle FBRM determinations in both pure water and a dispersion of fines. The results allow some general conclusions to be drawn about optimal focal point positions.     

Multifield hyperelasticity: variational theorems for complex bodies

We present some multifield variational principles for complex elastic solids characterized by any material microstructure. Some general constitutive arguments in the context of multifield hyperelasticity are also discussed.     

Characterization of a protease produced by a Trichoderma harzianum isolate which controls cocoa plant witches' broom disease

Background  

Several Trichoderma strains have been reported to be effective in controlling plant diseases, and the action of fungal hydrolytic enzymes has been considered as the main mechanism involved in the antagonistic process. However, although Trichoderma strains were found to impair development of Crinipellis perniciosa, the causal agent of cocoa plant witches' broom disease, no fungal strain is available for effective control of this disease. We have then undertaken a program of construction of hydrolytic enzyme-overproducing Trichoderma strains aiming improvement of the fungal antagonistic capacity. The protease of an indian Trichoderma isolate showing antagonistic activity against C. perniciosa was purified to homogeneity and characterized for its kinetic properties and action on the phytopathogen cell wall.     

A Multivalued Approach to the Planar Isosceles Three Body Problem

The isosceles three body problem consists of three point masses located on the vertices of an isosceles triangle on the plane. The two masses on the asymmetric edge are equal. This problem has been extensively studied but not as a perturbation of the Kepler problem. In this case we arrive at a differential inclusion as a natural formulation when we regularize the problem. We also derive an extension of the vectorfield that allows us to consider orbits across singular sets.      

Classical and accelerated evaluation of neutron escape probability

Neutron escape probability from a monodimensional plane medium is determined by resorting to the integral neutron transport equation.Both a projection procedure and an appropriate variational approach, yielding an acceleration of the convergence rate, are employed; their numerical results are reported and discussed.The theory is presented in a general form, since it can be applied directly to many basic problems in other branches of applied sciences.

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Riassunto La probabilità di fuga di un neutrone da un mezzo monodimensionale piano viene determinata nell'ambito della teoria integrale del trasporto. Vengono impiegati sia un procedimento proiezionale classico, che un opportuno metodo variazionale in grado di produrre un'accelerazione della velocità di convergenza; i relativi risultati numerici sono riportati e discussi. La teoria è esposta nella sua forma generale, in quanto può essere applicata direttamente a diversi problemi di base in altri rami delle scienze applicate.

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Work supported by the National Group for Mathematical Physics of C.N.R.