Search results for "fibre [scintillation counter]"

Fruit production and quality evaluation of four litchi cultivars (Litchi chinensis Sonn.) grown in Mediterranean climate

2017

Introduction - The agronomic and qualitative responses of the litchi fruit (Litchi chinensis Sonn.) grown in Mediterranean climate are not yet studied. In this study, yield components, physico-chemical and sensory traits of four commercial litchi cultivars were recorded over two productive seasons. Materials and methods - Fruits of the cvs Tai So, Wai Chee, Brewster and Kwai Mai were collected at commercial maturity stage and subjected to productive (yield, efficiency, number of fruits, crop load), analytical (fruit weight, transversal diameter, longitudinal diameter, moisture, total soluble solid content (TSS), titratable acidity (TA), TSS/TA ratio, seed weight, peel weight, percentage of …

Fibre extraction from oleaginous flax for technical textile applications: influence of pre-processing parameters on fibre extraction yield, size dist…

2017

International audience; Cultivated primarily for its seeds, oleaginous flax could also be valued for the different fractions that can be extracted from the straw. However, as the straws are not harvested with the same technique and care than for the textile flax, the classical scutching technique cannot be used. As a consequence, an “all fibre” device was used to perform the separation of the different constituents of the oleaginous flax straws. The different fractions were quantified for two retting levels and for two degrees of rewetting of the stems. The physical and mechanical properties of fibres were then evaluated. It appears that the relative amount of fibres extracted from oleagino…

Estimation of fibre orientation from digital images

2001

In this paper, estimation of fibre orientation is studied for fibre systems observable as a blurred greyscale image. The estimation method is based on scaled variograms observed along a set of sampling lines in different directions. The parameters of the orientation distribution are obtained numerically. Simulated data are used to study the statistical properties of the method.

Collision de similaritons optiques dans un amplificateur optique fibré Raman

2005

National audience; Nous abordons les aspects théoriques et expérimentaux de la génération et propagation de deux similaritons optiques de fréquences centrales différentes dans un amplificateur optique fibré Raman à dispersion normale. Nous observons les effets intervenant durant la collision des deux similaritons: un battement sinusoïdal apparaît dans la zone de recouvrement temporel des impulsions et des effets de la modulation de phase croisée modifient le spectre des similaritons. Les similaritons retrouvent néanmoins, après collision, leurs caractéristiques paraboliques.

Ondes scélérates et statistiques extrêmes dans les systèmes optiques fibrés

2011

This thesis deals with extremes statistics which has become an attractive subject in optics since a comparison with oceanic rogue waves has been proposed at the end of 2007. We report some potential mechanisms stimulating the rogue wave formation in the context of guided propagation of light in optical fibers. In a first part, we explore optical rogue waves in supercontinuums generated by fourth-order modulation instability and we propose a stabilization method based on the use of two continuous seeds. Then, we present a detailed study on Raman fiber amplifiers where we determine the conditions of emergence of giant structures : in presence of a partially incoherent pumping wave, a quasi-in…

Bright Retinal Lesions Detection using Color Fundus Images Containing Reflective Features

2009

Recently, the research community has developed many techniques to detect and diagnose diabetic retinopathy with retinal fundus images. This is a necessary step for the implementation of a large scale screening effort in rural areas where ophthalmologists are not available. In the United States of America, the incidence of diabetes is increasing among the young population. Retina fundus images of patients younger than 20 years old present a high amount of reflectance due to the Nerve Fibre Layer (NFL). Generally, the younger the patient the more the reflectance is visible. We are not aware of algorithms able to explicitly deal with this type of artifact.

Simplified technique for constitutive analysis of SFRC

2014

Steel fibre reinforced concrete (SFRC) has become widespread material in areas such as underground shotcrete structures and industrial floors. However, due to the absence of material models of SFRC reliable for numerical analysis, application fields of this material are still limited. Due to interaction of concrete with fibres, a cracked section is able to carry a significant portion of tensile stresses, called the residual stresses. In present practices, residual stresses used for strength, deflection and crack width analysis are quantified by means of standard tests. However, interpretation of these test results is based on approximation using empirically deduced relationships, adequacy o…

TENACITÀ ALLA FRATTURA INTERLAMINARE DI COMPOSITI CFRP SOTTOPOSTI A PROCESSI DI INVECCHIAMENTO IDROTERMICO

2011

In questo lavoro si è condotto uno studio degli effetti dell’invecchiamento idrotermico sulla tenacità alla frattura interlaminare in Modo I di laminati in composito CFRP con lay-up unidirezionale. I pannelli realizzati impiegano una resina epossidica DGEBA. Provini DCB sono stati ricavati in accordo con la norma ASTM D5528. Prove dinamico meccaniche DMTA sono state condotte per analizzare l’influenza dell’invecchiamento sulla temperatura di transizione vetrosa, e quindi sul grado di fragilità della matrice. Il lavoro descrive il set-up sperimentale per la determinazione delle Curve R, evidenziando l’influenza della morfologia del tessuto in carbonio. I valori di GIC di innesco e di propaga…

Idrothermal ageing of ionizing radiation cured epoxy matrices for carbon fibre composites

2008

Experimental results of RC columns strengthnened with Fiber Reinforced Cementitious Mortars

2012

The structural behaviour of reinforced concrete columns strengthened with a system made up of fibre nets embedded in an inorganic stabilized cementitious matrix was investigated. Specimens with circular and square cross-section were cast and subjected to monotonic uniaxial compression to investigate the efficiency of a Polypara-phenylene-benzo-bisthiazole (PBO) Fibre Reinforced Cementitious Mortars (FRCM) system in increasing both carrying capacity and ductility. The experimental results show that confinement with PBO fibre produced a noticeable increment in strength and ductility, though the low mechanical ratios of fibre considered were not always able to ensure hardening behaviour up to …