Search results for "Fiber"
showing 10 items of 2343 documents
Optical Sensor for Real-Time Detection of Trichlorofluoromethane
2019
Trichlorofluoromethane was once a promising and versatile applicable chlorofluorocarbon. Unaware of its ozone-depleting character, for a long time it was globally applied as propellant and refrigerant and thus led to significant thinning of the ozone layer and contributed to the formation of the so-called ozone hole. Although production and application of this substance were gradually reduced at an early stage, we still face the consequences of its former careless use. Today, trichlorofluoromethane is released during recycling processes of waste cooling devices, traded on the black market, and according to recent findings still illegally manufactured. Here, we present an optical sensor devi…
Numerical and Experimental Assessment of FRP-Concrete Bond System
2021
Fiber reinforced polymer (FRP) composite systems are widely used to repair structurally deficient constructions thanks to their good corrosion resistance, light weight and high strength. The quality of the FRP-substrate interface bond is a crucial parameter affecting the performance of retrofitted structures. In this study, ultrasonic testing have been used to assess the quality of the bonding. In the case of FRP laminates adhesively bonded to concrete, high scattering attenuation occurs due to the presence of concrete heterogeneities. The substrate material behaves almost like a perfect absorber generating a considerable number of short-spaced echo peaks that make the defect echo not disti…
Passively mode-locked erbium-doped double-clad fiber laser operating at the 322nd harmonic
2009
International audience; We report passive mode locking of a soliton erbium-doped double-clad fiber laser operating at the 322nd harmonic of the fundamental cavity frequency. Repetition rates up to 3 GHz have been obtained with pulses of 1 ps duration and 18 pJ of energy. The supermode suppression at the 322nd harmonic is better than 25 dB. In addition, the transition dynamics from a bunched state of pulses to stable harmonic mode locking is presented, revealing a very long time scale.
Engineering of Nanofibrous Amorphous and Crystalline Solid Dispersions for Oral Drug Delivery
2018
Poor aqueous solubility (<0.1 mg/mL) affects a significant number of drugs currently on the market or under development. Several formulation strategies including salt formation, particle size reduction, and solid dispersion approaches have been employed with varied success. In this review, we focus primarily on the emerging trends in the generation of amorphous and micro/nano-crystalline solid dispersions using electrospinning to improve the dissolution rate and in turn the bioavailability of poorly water-soluble drugs. Electrospinning is a simple but versatile process that utilizes electrostatic forces to generate polymeric fibers and has been used for over 100 years to generate synthet…
Implementation of eco-sustainable biocomposite materials reinforced by optimized agave fibers
2018
Abstract Although several works have recently been published in literature about biocomposites, i.e. about composites with polymeric matrix reinforced by natural fibers, only a few articles have been devoted to the implementation of high performance biocomposites for structural and semi-structural applications. The present study aims to give a contribution by considering biocomposites obtained by using an eco-friendly partially bio-based epoxy (green epoxy) and sisal (agave sisalana fibers) obtained by a proper optimization process. Through a systematic experimental analysis, three different types of biocomposites obtained with a suitable manufacturing process, such as random short fiber bi…
Influence of pulp bleaching and compatibilizer selection on performance of pulp fiber reinforced PLA biocomposites
2019
Numerical model for the characterization of biocomposites reinforced by sisal fibres
2018
Abstract Although several works have been recently published in literature about biocomposites, i.e. on innovative and ecofriendly polymer matrix composites reinforced by natural fibers, there are not studies on the influence of the waviness that various natural fiber present after their extraction. In order to give a contribution to the knowledge of the effects of the fiber waviness on the main mechanical properties of biocomposites, as the longitudinal Young modulus, in the present study a systematic numerical analysis has been carried out by using parametric models properly developed, that let the user to consider the effects of the key influence parameters as the fiber concentrations an…
The effect of alkaline treatment on mechanical properties of kenaf fibers and their epoxy composites
2015
Abstract In this work, kenaf fibers were pre-treated in a NaOH solution (6% in weight) at room temperature for two different periods (48 and 144 h). The chemical treatment of kenaf fibers for 48 h allowed to clean their surface removing each impurity whereas 144 h of immersion time had detrimental effect on the fibers surface and, consequently, on their mechanical properties. Untreated and NaOH treated kenaf fibers (i.e. for 48 h) were also used as reinforcing agent of epoxy resin composites. The effect of the stacking sequence (i.e. using unidirectional long fibers or randomly oriented short fibers) and the chemical treatment on the static mechanical properties was evaluated showing that t…
Parabolic pulse generation with active or passive dispersion decreasing optical fibers
2007
International audience; We experimentally demonstrate the possibility to generate parabolic pulses via a single dispersion decreasing optical fiber with normal dispersion. We numerically and experimentally investigate the influence of the dispersion profile, and we show that a hybrid configuration combining dispersion decrease and gain has several benefits on the parabolic generated pulses.
Tuning four-wave mixing through temperature in ethanol-filled photonic crystal fiber
2016
In this paper, continuous tuning of four-wave mixing bands in an ethanol-filled photonic crystal fiber is investigated. A wide tuning range of the parametric bands, from 745 nm to 920 nm (signal) and from 1260 nm to 1710 nm (idler), is achieved through the thermo-optic effect. This corresponds to a frequency tuning range higher than 2000 cm−1; such wide range can be particularly useful in applications that require broadband wavelength conversion, e.g., CARS microscopy. Numerical calculations are in good agreement with experimental measurements.