Comments on an experiment of resonant tunnelling between macroscopically distinct quantum levels

Summary In an important experiment performed on a SQUID system, Rouse, Han and Lukens report the first observation of resonant tunnelling between macroscopically distinct quantum levels. We support the experiment with the first theoretical approach for the phenomenon.     

Testing thermodynamic constitutive equations for polymers by adiabatic deformation experiments

During adiabatic deformation experiments on polyisobutylene of various molecular weights and on polyvinylacetate, the temperature change was measured. The thermal effects occurring during the subsequent stress relaxation were also recorded. From all data, the conclusion was drawn that the entropic elasticity theory is obeyed for temperatures sufficiently above the glass transition temperature. When the value of T_g is approached, some interesting energy effects become appreciable.     

Aspects of macroscopic quantum tunnelling in small Josephson junctions

Summary We study the effect of temperature on the lifetime of the resonant macroscopic quantum tunnelling voltage state. In view of experiments we consider a merit factor in order to balance between measuring extremely small signals of longer duration or larger signals of shorter duration.     

Exact solution for the gravitational field of a charged,magnetized, spinning mass

A family of solutions of the Einstein-Maxwell field equations is presented, corresponding to the exterior of stationaryaxisymmetric sources with charge, mass, angular momentum, and magnetic dipole moment. The Riemann tensor vanishes asymptotically for each member of the family; some solutions are asymptotically flat and some have NUT-like behavior asymptotically. For the asymptotically flat solutions, the gyromagnetic ratio may vary from zero to one. The corresponding value for the Kerr-Newman solution is one. A method for generating infinite chains of families of solutions of the Einstein-Maxwell equations is described.     

Spectral density method in classical statistical mechanics

The spectral density method in classical statistical mechanics is formulated and application to a linear classical spin system is made in the simplest approximation.     

On the conduction welding process of steels with the CO2 laser

Experiments on laser conduction seam welding were carried out with a 500 W CO₂ laser. Low carbon and stainless steel samples were butt welded and the optimum working conditions were found. An accurate analysis of these results showed such excellent agreement with the theoretical models that an a priori method could be formulated to calculate the values of all the related parameters, even including the laser focal spot radius to be used to ensure the best utilization of the beam energy.     

Radioprotective effects of glutathione on molecular systems

The paper investigates the effect of glutathione on model biological systems, such as enzymes, (lisozyme, alcoholdehydrogenase, α-chymotrypsin) and DNA base components. Our results on the inactivation of enzymes and on the chemical changes in DNA base components show a radioprotective action of glutathione in all systems. The results are discussed in terms of glutathione free radical reactivity and in the light of current hypothesis on the modification of the radiation damage given by thiol compounds.     

Design and validation of a single sphere multi-detector neutron spectrometer based on LiF: Mg,Cu,P thermoluminescent dosemeters

This communication describes a new neutron spectrometer consisting of pairs of ⁷Li and ⁶Li based thermoluminescent dosemeters (MCP-6, MCP-7) located at selected positions within a single moderating polyethylene sphere. The spatial arrangement of the dosemeters has been designed using the MCNPX Monte Carlo code to calculate the response matrix in order to obtain a nearly isotropic response for neutrons in the energy range up to 20 MeV. A partial validation of the calculated response matrix has been performed with the calibrated ²⁴¹Am–Be neutron source at the INFN–LNF Laboratory, using the shadow cone technique.     

Enhanced production of runaway electrons during a disruptive termination of discharges heated with lower hybrid power in the Frascati Tokamak Upgrade

We report on the observation of a large production of runaway electrons during a disruptive termination of discharges heated with lower-hybrid waves at the Frascati Tokamak Upgrade. The runaway current plateaus, which can carry up to 80% of the predisruptive current, are observed more often than in normal Ohmic disruptions. The largest runaway currents correspond to the slowest plasma current decay rates. This trend is opposite to what is observed in most tokamaks. We attribute this anomalous behavior to the acceleration of the preexistent wave-resonant suprathermal electrons during the disruption decay phase. These results could be relevant for the operation of the ITER tokamak whenever a sizeable amount of lower-hybrid power is made available.