Chilibon I.,Romanian National Institute for Optoelectronics
Defect and Diffusion Forum | Year: 2015
This paper presents some non-destructive evaluation methods of materials and structures, such as: pulse method, resonance method, direct measurement of the propagation velocity, pulseecho method, impact-echo method, acoustic emission evaluation, interferometry and infrared thermography. The methods are suitable for non-metallic materials, with rugged and nonhomogeneous structure, high attenuation coefficients for ultrasound propagation waves into materials, composites multilayer structures, etc. Some relevant measurement parameters are presented too. © (2015) Trans Tech Publications, Switzerland.
Moldovan O.T.,Romanian Academy of Sciences |
Meleg I.N.,Romanian Academy of Sciences |
Levei E.,Romanian National Institute for Optoelectronics |
Terente M.,Romanian Academy of Sciences
Ecological Indicators | Year: 2013
The task of designating biotic indicators for the assessment of the ecological status of freshwater environments is difficult. The purpose of this study was to develop a method that uses different ecological categories of Crustacea from the hyporheic zone of the Arieş River (north-western Romania) to monitor water and sediment quality. Samples of fauna, water and sediments were collected monthly during one year and classification and regression tree analysis was employed to identify bioindicator species and predict the effects of metal pollution on species diversity. For almost all dissolved metals and those partitioned into sediments in the hyporheic zone, microcrustaceans were good indicators of pollution, as they were absent in samples where concentrations of these elements were high. Most macrocrustaceans were good indicators only for high concentrations of Cu and Zn in water, and only one macrocrustaceans, Niphargus transylvanicus, could be considered as good indicator for sediment metal pollution. Hyporheic microcrustaceans such as Elaphoidella elaphoides, and representatives of Acanthocyclops and Bryocamptus cuspidatus should be used in future hyporheic zone quality assessments. The statistical method described by this study can also be applied for communities in surface habitats and for other types of pollutants. Typical hyporheos species can successfully indicate past or discontinuous pollution episodes and river basin managements should consider their use together with the benthic species to monitor water quality. © 2012 Elsevier Ltd. All rights reserved.
Zoran M.,Romanian National Institute for Optoelectronics
International Journal of Remote Sensing | Year: 2012
Geospatial data, coupled with ground-based observations where available, enable scientists to survey pre-earthquake signals in areas of strong tectonic activity. On 11 March 2011, at local time 14:46 JST (05:46 UTC), a mega-earthquake of moment magnitude (M w) 9.0 and shallow focus (24 km), known as the Tohoku-Oki earthquake, occurred on the Japan Trench plate boundary off the eastern shore of northern Honshu, followed by a large tsunami on the Pacific coast of Japan. This article is an attempt to analyse the development of thermal anomalies in land surface temperature (LST) preceding the 11 March 2011 Tohoku earthquake. In order to correlate LST variations and the Tohoku earthquake, we analysed time-series Moderate Resolution Imaging Spectroradiometer (MODIS) Terra/Aqua satellite daytime/night-time and National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) data. A clear rise of LST (1-10°C), which is apparently related to pre-seismic activity, was observed 2 weeks before the major event in all analysed satellite data around the earthquake epicentre. © 2012 Copyright Taylor and Francis Group, LLC.
Chilibon I.,Romanian National Institute for Optoelectronics |
Marat-Mendes J.N.,New University of Lisbon
Journal of Sol-Gel Science and Technology | Year: 2012
New advances in the sol-gel processing of ferroelectric ceramic powders and thin films and recently, scientific and technological interests in ferroelectric ceramics have been focused particularly on thin films. This is mainly due to their great potential applications in integrated electronics as passive components and as non-volatile ferroelectric memories, optoelectronic devices, etc. Special attention has been paid to the effects of the microstructure and composition on the piezoelectric properties of ferroelectric ceramic powders and thin films, and various characterization techniques are reported. This paper introduces the basic principles governing ferroelectricity and lists the various materials which exhibit these properties. The processing of ferroelectric ceramics and thin films in general and sol-gel processing in particular, with some examples are described. Finally, important applications of ferroelectric films and microstructure examination as well as powerful techniques are briefly discussed. © 2012 Springer Science+Business Media New York.
Calin M.A.,Romanian National Institute for Optoelectronics |
Parasca S.V.,Clinical Hospital for Plastic Surgery and Burns
Lasers in Medical Science | Year: 2010
The optical properties of the skin (absorption coefficient, scattering coefficient, refractive index) may serve to characterize the skin and are important for correct light dosimetry in many optical diagnostic procedures and laser treatments especially photodynamic therapy and laser therapy. We determined in vivo the optical properties of tissues near the wrist, elbow and knee in subjects of different ages using diffuse reflectance spectroscopy, having in view the establishment of laser system types for the laser treatment of posttraumatic lesions in subjects of different ages. Diffuse reflection of light from biological tissue is due to the variation in refractive index of tissular and cellular components and the surrounding medium and depends on the wavelength of the incident optical radiation. The diffuse reflectance spectrum of the tissues tested showed two maxima localized at λM1 ≈ 610 nm and λM2 ≈ 675 nm. Laser systems which emit radiation at these wavelengths are not efficient for the treatment of joints, regardless of the subject's age. The deep tissues have a strong absorption in the range 630-700 nm, which indicates that for treating posttraumatic lesions we can use laser systems such as the He-Ne laser, the GaAlAs laser, and the InGaAlAs laser. Using Kramers-Kronig analysis of the diffuse reflectance spectra, the optical parameters n(ω) and k(ω) were determined. The age-dependent changes in these optical parameters of tissue must be taken into consideration and the use of laser treatments or optical diagnosis methods must be based on a knowledge of these properties and of the optical radiation parameters. © Springer-Verlag London Ltd 2009.