Experimental evidence of bifurcating nonlinear normal modes in piecewise linear systems

A system with piecewise linear restoring forces, typical of damaged beams with a breathing crack, exhibits bifurcations characterized by the onset of superabundant modes in internal resonance with a significantly different shape than that of modes on a fundamental branch. A 2-DOF frame with piecewise linear stiffness is analyzed by means of an experimental investigation; the frame is forced by an harmonic base excitation and the operative modal shapes as well as the response amplitude are directly measured; the results are compared with numerical outcomes for different damping values. This study shows that the shapes and the frequencies of certain nonlinear normal modes (NNMs) of the related autonomous system strongly affect the forced response, in both the numerical and the experimental environments. Therefore, it is possible to match the NNM with the forced response of the system, leading to the prospect of identifying the severity and position of the damage from experimental tests.     

Practical synthesis of novel purine analogues as Hsp90 inhibitors

The development of a straightforward synthesis of 4-amino-6-benzyl-6H-pyrrolo[3,4-d]pyrimidine and 7-amino-2-benzyl-2H-pyrazolo[4,3-d]pyrimidine derivatives allowed for the preparation of a small family of potential Hsp90 inhibitors. Some of the newly synthesized compounds showed Hsp90 inhibitory activity in preliminary biological assays.     

Sul primo principio della termodinamica per I materiali semplici

It is known that the correct formulation of rational thermodynamics for mixtures requires an inequality more general than the Clausius-Duhem principle. On the other hand, in a recent paper on the thermodynamics of “interstitial working”[2] it was pointed out the need to correct the classical balance law of internal energy. There is no good reason for modifying both, however. It is worth to derive, hence, the most general expression of the Second Law by keeping the First in its classical form, as shown in a previous paper [4], or, what is the object of this article, to look for the most general formulation of the First Law assuming the Clausius-Duhem inequality as the Second. As a consequence of results obtained here, the statement of the First Principle needs not to be changed in the class of “simple material”. Thus, it is worth noting that a generalized expression of the First Law applies only non-simple materials, like as Korteweg fluids.

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Lavoro eseguito nell'ambito delle attività del G.N.F.M. del C.N.R. e dei progetti di ricerca ministeriali 40% e 60%.     

Scalar quantum electrodynamics on lattice correlation inequalities and infinite volume limit

We consider Wilson's lattice approximation to scalar Quantum Electrodynamics. We establish correlation inequalities of Griffiths-Kelly-Sherman type and a rigorous transfer matrix formalism, from which existence and non triviality of the infinite volume limit follow.     

Use of high-efficiency packed columns for gas-solid chromatography : V. Micropacked columns

Micropacked columns are constructed using graphitized carbon black as a support for gas-liquid-solid chromatography. Their effectiveness is evaluated in terms of Van Deemter plots, flow-rates, inlet pressure and column capacity. It is shown that such columns, by choosing an appropriate liquid phase, can be used for a wide range of temperatures and types of compound. Analytical applications connected with the analysis of complex organic mixtures in water are discussed. The problems of the analysis of air pollutants are also considered.     

Scalar Quantum Electrodynamics on the lattice as classical statistical mechanics

Wilson's lattice approximation allows us to apply classical statistical mechanics ideas to the study of Scalar Quantum Electrodynamics. Our main tools are Griffiths-Kelly-Sherman inequalities, the transfer matrix formalism and exponential bounds. Our main result is the existence of the infinite volume limit for every value of the coupling parameters.     

Evaluation by chemical parameters of the pollution state of the agricultural-industrial settlement of the Fucino Plain

In the present work are reported the results of a monitoring on a vast scale, carried out through evaluation of opportune chemical parameters, of the pollution state of the agricultural-industrial settlement of the Fucino Plain. The parameters took into consideration have been the presence of wide consumption pesticides and of ionic species as Cl-, NO2-, NO3-, NH4+, the quantification of the dissolved oxygen, of the temperature, of the conductivity, of pH and eH. Collected data are used for chemometric elaboration. The water systems examined, by means of drawing campaigns carried out at regular intervals in winter, spring, summer, and autumnal seasons, are represented by superficial waters constituting a network of irrigation canals fed by stratum and meteoric waters. In this work are reported the results relative to the drawing campaigns.