Showing papers by "Polytechnic University of Turin published in 1971"
TL;DR: A new polynomial class is considered for the design of the transmission functions of lowpass RC active filters, which have higher degree but lower Q factors than those computed with the classical Chebyshev method.
Abstract: A new polynomial class is considered for the design of the transmission functions of lowpass RC active filters. These transmission functions have higher degree but lower Q factors than those computed with the classical Chebyshev method.
9 citations
TL;DR: In this article, the authors studied the relationship between fatigue and brittleness and showed that the slope of the curves decreases with increasing britteness and for the silicon alloy becomes almost zero at liquid helium temperature.
Abstract: Fatigue of Armco iron and of Fe-Si 5% is studied at liquid nitrogen and liquid helium temperatures in symmetric torsion, and by estimating the plastic strain amplitudes from internal friction measurements and from comparison with the static stress-strain curves. It is shown that, contrary to previous experiments of MacCammon and Rosenberg, iron in pure shear still shows a definite fatigue curve also at 4°K. The corresponding plastic strain amplitude at the fatigue limit is of the order of 10−4. For Fe-Si 5%, on the other hand, fatigue at 4°K almost disappears, and this disappearance seems associated with a critical value of the strain to fracture of the order of 10−5. In the representation of Manson and Coffin of the plastic strain amplitude as a function of the number of cycles it is shown that the slope of the curves decreases with increasing brittleness and for the silicon alloy becomes almost zero at liquid helium temperature. The results obtained on the relationship between fatigue and britt...
7 citations
TL;DR: In this article, general properties of correlation functions in ordered magnetic systems were analyzed in the framework of the functional approach to statistical mechanics, and the case of the anisotropy described by an internal field was worked out.
Abstract: We analyze, in the framework of the functional approach to statistical mechanics, general properties of correlation functions in ordered magnetic systems. The aim of this paper is to investigate what consequences can be derived from the requirement of invariance of the theory under local infinitesimal spin rotation. The extension of the method that we introduce, to include anisotropic Hamiltonians, is discussed, and the case of the anisotropy described by an internal field is worked out. Our main results are a set of generalized Ward identities, a microscopic definition of the stiffness constant as a static limit of a local response function, and an exact asymptotic expression for the correlation functions of interest, for zero temperature and small wave length and frequency. Modifications to the hydrodynamic expression for correlation functions in the case where anisotropy is present are also discussed.
4 citations
TL;DR: In this article, a spatial impulsive interaction model is applied to the calculation of drag and lift coefficients for flat plate, sphere and circular cylinder with side-wind in hyperthermal free-molecule flow.
Abstract: A spatial impulsive interaction model is applied to the calculation of drag and lift coefficients for flat plate, sphere and circular cylinder with side-wind in “hyperthermal” free-molecule flow. Obtained results for flat plate are also compared with the corresponding coefficients calculated by Hurlbut and Sherman in1968 according to the Nocilla reemission model(1962).
3 citations
TL;DR: In this paper, a theoretical model to estimate reflected and transmitted shocks has been outlined, and experiments have been carried out measuring pressures upstream and downstream of the orifice plate located inside it.
3 citations
TL;DR: In this paper, the aerodynamic problems of re-entry of a spacecraft are considered. Among these problems, some of which concern properties of the trajectory, others are related to the various regimes of flow around the body during the reentry, and still others still are consequence of the high speeds and high temperature effects.
Abstract: Re-entry of a spacecraft leads to aerodynamic problems, some of which concern properties of the trajectory, others are related to the various regimes of flow around the body during the re-entry, others still are consequence of the high speeds and high temperature effects. Among these problems are here considered the following:
2 citations
TL;DR: In this article, the elastic equilibrium configuration of the helical spring interposed between driver and driven shafts is analyzed, and relations between the geometrical and dynamical parameters are found.
Abstract: Frictional couplings, transmitting torque in only one direction, are studied in order to find the maximum value of the transmissible torque. For this purpose, the elastic equilibrium configuration of the helical spring interposed between driver and driven shafts is analyzed, and relations between the geometrical and dynamical parameters are found. The results are obtained through numerical calculations and tabulated for different values of the influencing physical factors.
2 citations
TL;DR: Reflected and transmitted pressure waves are generated by the interaction which takes place when an incident pressure wave reaches an orifice placed inside a duct, with initial steady flow through the orifice before this interaction as discussed by the authors.
Abstract: Reflected and transmitted pressure waves are generated by the interaction which takes place when an incident pressure wave reaches an orifice placed inside a duct, with initial steady flow through the orifice before this interaction.
1 citations
01 Jan 1971
TL;DR: In this article, the authors expose quelques considerations sur le phenomene de la diffusion of the vapeur d'eau a travers des materiaux poreux en conditions stationnaires and, sur la base de certaines hypotheses simplifiees, developpe le probleme en partant de la loi de Fick.
Abstract: Resume : On expose quelques considerations sur le phenomene de la diffusion de la vapeur d'eau a travers des materiaux poreux en conditions stationnaires et, sur la base de certaines hypotheses simplifiees, on developpe le probleme en partant de la loi de Fick.
On fait la description d'un appareil realise pour la mesure de la permeabilite a la vapeur d'eau a travers des materiaux poreux, appareil qui comprend deux chambres a temperature et degre hygrometrique controles, separees par le panneau du materiel en essai.
L'appareil est pourvu d'un dispositif qui mesure la masse de vapeur d'eau transmise a travers le panneau.
On examine ensuite les resultats de certains essais faits sur des materiaux tels que le liege expanse emulsionne avec bitume, mousse phenolique et polystyrenes expanses.