Volume Contents

Multibody System Dynamics -     

A novel supply and process independent ECL-to-CMOS level converter for VLSI systems

This paper presents novel circuit schemes for the ECL-to-CMOS level conversion in BiCMOS digital ICs. The proposed topologies show electrical characteristics (delay time, duty cycle, output currents) independent from the supply voltage and process variations. Thus, they are suitable to be used with both 3.3 V and 5 V supplies and over a huge temperature range. Moreover, their average current consumption is lower than 320 μA while operating with a signal frequency higher than 120 MHz. The propagation delay time in the presence of the load of a minimum-sized inverter ranges from 1 ns to 1.2 ns for the two different proposed solutions at room temperature, and varies less than 2% over the temperature range 0° to 70°. A prototype of the proposed cell has been integrated in a conventional 0.8 μm BiCMOS technology and the measurements confirm the. expected performance.     

Education and the risk of physical disability and mortality among men and women aged 65 to 84: the Italian Longitudinal Study on Aging

BACKGROUND: Most studies report that people with higher education enjoy better health and longer life. Although it is well known that most risk factors are more common among individuals with a lower level of education, the underlying mechanism of this association is not fully understood. The objective of this study was to assess the association between education, disability, and mortality. METHODS: We analyzed data on 1,817 men and 1,643 women, aged 65-84 years, to assess the association of educational level with physical disability and mortality adjusting for age, sex, smoking habit, occupation, and major chronic conditions. RESULTS: The association between educational level and disability was characterized by a dose-response effect, with the relative odds significantly decreased by about 30%, 60%, and 79% in those with 4 or 5, 6 to 8, and more than 8 years of education, compared to those with 3 or less years of education. Death rates were lower among persons with 4 or more years of education compared to those with less education. However, after adjusting for disability status, education was no longer associated with mortality (RR=0.97, CI=0.65-1.43). CONCLUSIONS: The strong association of low education with disability found in this study may explain the inverse association with mortality reported in previous studies. Disability, indeed, seems to be the mediator between education and mortality and might be due to the higher severity level of diseases, leading to death, in the lower educated group.     

A first principles study of small Cun clusters based on local-density and generalized-gradient approximations to density functional theory

Neutral and anionic Cu_n clusters (Cu₂, Cu₃, Cu₆ and Cu₇⁻) are studied within density functional theory via (a) the local-density approximation (LDA) and (b) the generalized-gradient approximation (GGA) of Perdew and Wang (GGA-PW) for exchange and correlation. GGA reduces by ˜20% the binding energies, while the bond lengths are increased by ˜3–4%. The different levels of GGA approximation, involving optimization of the electronic density and/or of the geometry, are shown in detail. In the case of Cu₆ the GGA configurational ground state is a planar structure of D_3h symmetry. This result differs from the one obtained by LDA, where the three different isomers (one two-dimensional and two three-dimensional) were found to lie within 0.04 eV.     

Structural oscillation modes identification by applying controlled loads and using microwave interferometry

Radar interferometry, capable of remote detection of displacements and deformations of a structure, has been successfully experimented in a number of case studies. Radar interferometry offers high-speed range imaging and range displacement measurement capability, but it lacks in the identification of the different kinds of modes usually excited in a dynamic test. In this paper an approach to the measurement capable of identifying bending and torsional oscillation modes is described. The basic idea rely on the application of suitable loads to the structure under test in order to cause controlled changes of its frequency response. The results of such a dynamic test, performed on a canopy, are reported.     

The detection of the presence of hazelnut oil in olive oil by free and esterified sterols

Genuine olive and hazelnut oils from diverse geographical origins, as single varieties and blends, were mixed at different percentages and analysed by the method based on the quantification of free and esterified sterols. Two formulas based on three sterols (Campesterol, Δ⁷-stigmastenol and Δ⁷-avenasterol) together with empirical decision rules were able to detect the presence of hazelnut oil in olive oil when the percentage of the former was more than 6–8%, although this figure was much lower in the most of the adulterations. Results of univariate and multivariate statistical procedures based on the analysis of 116 samples are presented in support of the method efficiency.     

Comparison of Various Solvent Media Efficiency in the Grinding of a Frit Containing Zirconium Oxide

In the present work thermal and chemical properties of a glass-ceramic frit containing zirconium oxide are evaluated after milling in various polar and nonpolar solvents. Particle-size distribution is one of the main variables investigated to evaluate the efficiency of several solvents. Milling in various solvents does not affect the thermal properties of the glass while the presence of polar groups in the solvent molecule increases the cation release from the glass.     

Rehabilitation of reinforced concrete axially loaded elements with polymer-modified cementicious mortar

The aim of the paper is to investigate the compatibility and the efficiency of the rehabilitation intervention on reinforced concrete columns with polymer-modified cementicious mortar. This paper presents the results of experimental tests on axial behaviour of reinforced concrete columns, with square cross-section, repaired by polymer-modified cementicious mortar. Tests were repeated varying repair thickness, which included or did not include the steel reinforcement on one face of the square column. Despite this type of intervention is quite common in practice, the effect of repair thickness on the intervention efficiency, in relation to the existing steel reinforcement configuration, had not been previously studied in detail for axially loaded elements.Results were discussed and compared with those from control columns, which were tested in non-damaged, non-repaired conditions. The main findings of this work can be summarized as follows. The repair cannot restore the load-bearing capacity of non-damaged control columns, although they give acceptable results. Repairs that include the longitudinal reinforcement show good properties, with stable behaviour, sharing of loads, and plasticization of the material before failure, whereas thin repairs that do not include the reinforcement do not have adequate performance due to premature debonding. Non-linear numerical models also confirmed the different behaviour of the two types of repair.