dielectric permittivity

TDR-based monitoring of rising damp through the embedding of wire-like sensing elements in building structures

In this work, the validation and the practical implementation of a methodology exploiting a time domain reflectometry (TDR)-system for monitoring rising damp in building structures are described in detail. The proposed system employs wire-like, passive, diffused sensing elements (SEs) that are embedded, at the time of construction or renovation, inside the walls of the building to be monitored. The SEs remain

Effect of applied pressure on patch resonator-based measurements of moisture level for cultural heritage materials

In this paper, preliminary results of variations as a function of applied pressure in the reflection coefficient of a planar patch resonator, placed in contact with cultural heritage stone materials, will be presented. The general aim of the experimental project is to correlate the resonant frequency of the planar sensor, for the different pressures applied to the resonator, with the different levels of water content θv of the tested stone material.

An improved noninvasive resonance method for water content characterization of cultural heritage stone materials

In this work, a noninvasive microwave-based system for monitoring water content of Cultural Heritage stone
materials is presented. In particular, by placing a planar resonator in contact with the stone sample, an experimental
relationship between resonant frequency and water content is obtained.
To verify the suitability of the system, experimental tests are carried out on several types of stones: gentile;
leccese; carparo; red brick; and red brick fabricated at high temperatures. The first three types of stones are

TDR-based measurements of water content in construction materials for in-the-field use and calibration

In this paper, a time domain reflectometry (TDR)-based system for measuring water content of raw construction materials is presented. The proposed system relies on the fact that the presence of water leads to an increase of the dielectric permittivity of materials; therefore, from TDR-based permittivity measurements, it is possible to infer the water content value. In practical applications, the proposed system could be used for assessing the intrinsic water content of construction materials before they are poured into the concrete mixture.

Compensating for bulk density effect in permittivity-based moisture content measurements on cultural heritage materials

Dielectric permittivity-based measurement techniques are establishing themselves as attractive solutions for assessing the moisture content of historic masonry materials. The relative simplicity of the measurement principle and the inherent adaptability to diverse operating conditions are two of the most notable features of these techniques. In spite of these specific advantages, however, there are still some aspects that hinder the widespread use of permittivity-based moisture content measurement systems, and make their standardization difficult.

Feasibility of a wearable reflectometric system for sensing skin hydration

One of the major goals of Health 4.0 is to offer personalized care to patients, also through real-time, remote monitoring of their biomedical parameters. In this regard, wearable monitoring systems are crucial to deliver continuous appropriate care. For some biomedical parameters, there are a number of well established systems that offer adequate solutions for real-time, continuous patient monitoring. On the other hand, monitoring skin hydration still remains a challenging task.

Dielectric permittivity of aqueous solutions of electrolytes probed by THz time-domain and FTIR spectroscopy

We have measured the dielectric permittivity of pure water and aqueous chlorides solutions in the range 0.2-1.5THz. We considered the relaxation spectral function as the weighted sum of two independent single-parameter Debye functions. Such an approach allowed to drastically reduce the number of the parameters used in the fit which we set only by physical considerations.

Influence of magnetite nanoparticles on the dielectric properties of metal oxide/polymer nanocomposites based on polypropylene

Structure and dielectric properties of polymer nanocomposites based on isotactic polypropylene and iron oxide
(Fe3O4) nanoparticles are studied. Distribution of magnetite nanoparticles in a polymer matrix was studied by
scanning electron microscopy (SEM, Carl Zeiss). Dielectric properties of nanocomposites were examined by
means of E7-21 impedance spectrometer in the frequency range of 102–106 Hz and temperature interval of
298–433 K. The frequency and temperature dependences of the dielectric permittivity ε, as well as the

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