Search results for "character"
showing 10 items of 2956 documents
Can be GPR technique useful for strength characterization of concrete?
2010
The possibility of material characterization through the GPR measurements, taking into account the integration with the ultrasonic technique, has been studied and possible relationships between the permittivity of materials and their bulk density are discussed. We present here two different approaches. The first one describes an attempt to correlate the mechanical strength of concrete (as well the ultrasonic velocity) with the permittivity of the material. A series of samples of concrete, characterized by different material properties, were used for georadar and ultrasonic measures, seeking correlations among experimental data. The second approach illustrates the comparison between GPR and …
Evolution of the complex permittivity of biological tissue at microwaves ranges: Correlation study with burn depth
2014
The evolution of the muscle tissue's complex permittivity represents a growing interest in terms of characterization in medicine and biology. The influence of a burned part on the permittivity is not very developed. In this work, an estimation of the complex permittivity of biological tissues is performed as a function of the depth of burn tissues. The sensor, an open-ended coaxial probe, is placed directly against each sample. The evolution of the complex permittivity is studied for two measurements conditions (in the air and in a physiological solution). A correlation study is attempted with the depth of burn tissue.
Processing, basic characterization and standard dielectric measurements on PLZTx/65/35 (4 ≤x≤ 11) ceramics
2014
The influence of external stress (0–800 bar) on the dielectric properties of lead lanthanum zirconium titanate (PLZT) x/65/35 (4 ≤ x ≤ 11) ceramics was investigated. Applying uniaxial pressure leads to a change in the peak intensity of the electric permittivity (ϵ), in its frequency dispersion as well as in the dielectric hysteresis. The peak intensity of ϵ becomes broader and shifts to lower temperatures for PLZT x/65/35 with x = 4, 7, 9.75 and 11, with increasing pressure, on heating. It was concluded that applying uniaxial pressure induces an increase of Tm, and thus has a similar effect as the increase of the Ti ion concentration in the lead zirconium titanate (PZT) system. Results base…
Dielectric characterization of biocompatible hydrogels for application to Epidermal RFID devices
2015
Functionalized skin-like membranes are currently under investigation for the design of a new class of Epidermal Electronics devices for sensing and healing applications. The dynamic response of epidermal antennas in presence of absorption and release of fluids is a key-point to design RFID radio-sensors and actuators. This paper addresses the characterization of the dielectric property of PVA-based biocompatible hydrogel membranes in the UHF RFID band by means of a modified ring resonator. Samples having different compositions are measured in the dry state as well as when exposed to a progressive release of body fluids emulating perspirations or wound exudates. It was found that the permitt…
Development and characterization of xyloglucan-poly(vinyl alcohol) hydrogel membrane for Wireless Smart wound dressings
2018
Abstract Hydrogel-based smart wound dressings that combine the traditional favourable properties of hydrogels as skin care materials with sensing functions of relevant biological parameters for the remote monitoring of wound healing are under development. In particular, lightweight, ultra-high frequency radiofrequency identification (UHF RFID) sensor are adjoined to xyloglucan-poly(vinyl alcohol) hydrogel films to battery-less monitor moisture level of the bandage in contact with the skin, as well as wireless transmit the measured data to an off-body reader. This study investigates the swelling behavior of the hydrogels in contact with simulated biological fluids, and the modification of th…
Temperamental characteristics in childhood migraine without aura: a multicenter study
2013
Maria Esposito,1 Rosa Marotta,2 Beatrice Gallai,3 Lucia Parisi,4 Giuseppina Patriciello,1 Serena Marianna Lavano,2 Giovanni Mazzotta,5 Michele Roccella,4 Marco Carotenuto11Center for Childhood Headache, Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, Second University of Naples, Naples, Italy; 2Department of Psychiatry, "Magna Graecia" University of Catanzaro, Catanzaro, Italy; 3Unit of Child and Adolescent Neuropsychiatry, University of Perugia, Perugia, Italy; 4Child Neuropsychiatry, Department of Psychology, University of Palermo, Palermo, Italy; 5Unit of Child and Adolescent Neuropsychiatry, AUSL Umbria 2, …
Topological effects in ring polymers. II. Influence of persistence length
1999
The interplay of topological constraints and persistence length of ring polymers in their own melt is investigated by means of dynamical Monte Carlo simulations of a three dimensional lattice model. We ask if the results are consistent with an asymptotically regime where the rings behave like (compact) {\em lattice animals} in a self-consistent network of topological constraints imposed by neighbouring rings. Tuning the persistence length provides an efficient route to increase the ring overlap required for this mean-field picture to hold: The {\em effective} Flory exponent for the ring size decreases down to $\nu \stackrel{<}{\sim} 1/3$ with increasing persistence length. Evidence is provi…
Characteristic Length Scales and Radial Monomer Density Profiles of Molecular Bottle-Brushes: Simulation and Experiment
2010
Extensive Monte Carlo simulations are presented for bottle-brush polymers under good solvent conditions, using the bond fluctuation model on the simple cubic lattice. Varying the backbone length (from Nb = 67 to Nb = 259 effective monomers) as well as the side chain length (from N = 6 to N = 48), for a physically reasonable grafting density of one chain per backbone monomer, we find that the structure factor describing the total scattering from the bottle-brush provides an almost perfect match for some combinations of (Nb, N) to experimental data of Rathgeber et al. [J. Chem. Phys. 2005, 122, 124904], when we adjust the length scale of the simulation to reproduce the experimental gyration r…
Scattering function of semiflexible polymer chains under good solvent conditions
2012
Using the pruned-enriched Rosenbluth Monte Carlo algorithm, the scattering functions of semiflexible macromolecules in dilute solution under good solvent conditions are estimated both in $d=2$ and $d=3$ dimensions, considering also the effect of stretching forces. Using self-avoiding walks of up to $N = 25600$ steps on the square and simple cubic lattices, variable chain stiffness is modeled by introducing an energy penalty $\epsilon_b$ for chain bending; varying $q_b=\exp (- \epsilon_b/k_BT)$ from $q_b=1$ (completely flexible chains) to $q_b = 0.005$, the persistence length can be varied over two orders of magnitude. For unstretched semiflexible chains we test the applicability of the Krat…
A CHARACTERIZATION OF THE WEAK RADON–NIKODÝM PROPERTY BY FINITELY ADDITIVE INTERVAL FUNCTIONS
2009
AbstractA characterization of Banach spaces possessing the weak Radon–Nikodým property is given in terms of finitely additive interval functions. Due to that characterization several Banach space valued set functions that are only finitely additive can be represented as integrals.