Search results for "PERT"
showing 10 items of 7689 documents
Hydrothermal Aging of an Epoxy Resin Filled with Carbon Nanofillers
2020
The effects of temperature and moisture on flexural and thermomechanical properties of neat and filled epoxy with both multiwall carbon nanotubes (CNT), carbon nanofibers (CNF), and their hybrid components were investigated. Two regimes of environmental aging were applied: Water absorption at 70 °
Study of water adsorption and capillary bridge formation for SiO(2) nanoparticle layers by means of a combined in situ FT-IR reflection spectroscopy …
2014
Water adsorption and capillary bridge formation within a layer of SiO2-nanoparticles were studied in situ by means of a combination of quartz crystal microbalance (QCM-D) with dissipation analysis and Fourier transformation infrared reflection absorption spectroscopy (FT-IRRAS). FT-IR data were employed to distinguish the “ice-like” and “liquid-like” contributions and to support the analysis of the QCM-D data concerning mass change and dissipation. Combined measurements show that for SiO2-nanoparticles with a diameter of about 250 nm, the formation of two adsorbed monolayers of water as well as bulk water leads to a rather linear increase in the dissipation for relative humidity values of u…
Irradiation effects on the OH-related infrared absorption band in synthetic wet silica.
2007
The effects of b-irradiation on the OH-related infrared (IR) absorption band in synthetic wet silica samples have been investigated by Fourier transform infrared spectroscopy. Depending on the accumulated doses, b-irradiation affects different zones of the IR composite band at about 3670 cm 1 , assigned to the OH stretching modes of silanol groups. These modifications are independent of the original OH content. The results are discussed considering possible radiation-induced changes of the silanol bonding configuration and of the glass network. These are monitored by revealing the IR band a 2260 cm 1 , which is related to the distribution of Si–O–Si bond angle. We have identified the existence of…
Temperature effects on the IR absorption bands of hydroxyl and deuteroxyl groups in silica glass
2009
Abstract In this report we will show the changes of the band shape of the hydroxyl group (SiOH) infrared (IR) absorption band (∼3670 cm −1 ) in silica glass induced by lowering temperature in the range from 290 to 20 K. This band is considered as the overlap of several spectral components associated to the vibrational activity of hydroxyl groups in different bond configurations. By a suitable analysis of the experimental band profile in terms of different sub-bands, we studied the thermal evolution of each component and we reconsidered their assignations. For comparison we examined the SiOD absorption band (∼2710 cm −1 ) as a function of temperature as well. Our data can be interpreted as a…
Adaptation and Validation of the Spanish Version of the Instrument to Evaluate Nurses’ Attitudes Toward Communication With the Patient for Nursing St…
2021
Communication is essential to quality of care and patient satisfaction. It has been linked to positive patient outcomes, increased engagement, improved health outcomes and safe practices. Given these benefits and the association between attitudes and behaviours, as behaviours can be predicted by studying attitudes, assessing nursing students' attitudes toward patient communication is critical as future nursing professionals. For this purpose, the main aim of this study was to adapt and validate an instrument to measure nurses´ attitudes towards communication (ACO) for nursing students. The attitudes towards communication with patients were analyzed. Then, differences in the dimensions of th…
Characterization and Tuning of Ultra High Gradient Permanent Magnet Quadrupoles
2009
The application of quadrupole devices with high field gradients and small apertures requires precise control over higher order multipole field components. We present a new scheme for performance control and tuning, which allows the illumination of most of the quadrupole device aperture because of the reduction of higher order field components. Consequently, the size of the aperture can be minimized to match the beam size achieving field gradients of up to $500\text{ }\text{ }\mathrm{T}\text{ }{\mathrm{m}}^{\ensuremath{-}1}$ at good imaging quality. The characterization method based on a Hall probe measurement and a Fourier analysis was confirmed using the high quality electron beam at the M…
Producción y difusión digitales de las humanidades no vanguardistas en el siglo XX: el ejemplo de la filología catalana medieval
2014
Aquest article ofereix un panorama històric dels formats digitals emprats al segle XX en un petit camp de les Humanitats: la filologia catalana medieval, com a exemple de moltes altres àrees de recerca similars, no avantguardistes, i centrades en estudis textuals. S'hi mostra que la gestió textual i de vocabulari, així com les bades de dades lèxiques i bibliogràfiques, van constituir els seus primers projectes. L'article conclou amb una brevíssima valoració dels desafiaments digitals en el futur immediat, especialment en eines de publicació: pdf front a epub, i l'accelerat procés de compartir la recerca més recent a través de les xarxes socials d'investigadors. S'hi defén la via de la cultu…
Modelling Aspects in Accumulative Roll Bonding process by Explicit Finite Element Analysis
2013
Accumulative Roll-Bonding (ARB) process is a severe plastic deformation (SPD) process, capable of developing grains below 1 μm in diameter and improving mechanical properties of the material. In this study, the authors compared two different FE-codes with respect of its applicability for numerical analysis of the ARB process. Modelling this process was achieved using the explicit code for Abaqus/CAE both in 2D and 3D. The proposed model was used to assess the impact of ARB cycles on the final material properties. The numerical results in 2D and 3D were compared and contrasted. The research work presented in this paper is focused on the simulation optimization based on CPU time minimization.…
Non-destructive automatic determination of aspect ratio and cross-sectional properties of fibres
2015
A novel method for computerised estimation of the aspect ratio distribution and various cross-sectional geometrical properties of fibres in short-fibre reinforced composites is proposed. The method, based on X-ray micro-computed tomography, is non-destructive and does not require user intervention. Based on results on specially fabricated model material, the accuracy and precision of the method seems adequate. The method is applied in analysing a manufacturing process of wood fibre reinforced thermoplastic composite. The results indicate a significant decrease of the aspect ratio of fibres during the processing steps. Finally, the feasibility of the method is assessed by estimating paramete…
Accuracy of doppler echocardiography in measuring right-heart pressure in patients with pulmonary hypertension
2010
The assessment of pulmonary pressure is of great clinical importance not only for diagnostic purposes, but also for prognosis in patients with pulmonary arterial hypertension. The present study was undertaken on a consecutive basis with a group of patients who had had a previous diagnosis of pulmonary hypertension based on echocardiography, and were referred to our institute. The aim of this study was to determine how accurate Doppler echocardiography is in measuring right-heart pressures.