Search results for "Fiber"
showing 10 items of 2343 documents
An experimental and modeling study of the oxidation of 3-pentanol at high pressure
2019
International audience; High pressure oxidation of 3-pentanol is investigated in a jet-stirred reactor and in a shock tube. Experiments in the reactor were carried out at 10 atm, between 730 and 1180 K, for equivalence ratios of 0.35, 0.5, 1, 2, 4 and 1000 ppm fuel, at a constant residence time of 0.7 s. Reactant, product and intermediate species mole fractions were recorded using Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC). Ignition delay times were measured for 3-pentanol/O2 mixtures in argon in a shock tube at 20 and 40 bar, in a temperature range of 1000–1470 K and for equivalence ratios of 0.5, 1 and 2. The fuel did not show any low-temperature reactivity…
The case for strategic international alliances to harness nutritional genomics for public and personal health
2005
Nutrigenomics is the study of how constituents of the diet interact with genes, and their products, to alter phenotype and, conversely, how genes and their products metabolise these constituents into nutrients, antinutrients, and bioactive compounds. Results from molecular and genetic epidemiological studies indicate that dietary unbalance can alter gene-nutrient interactions in ways that increase the risk of developing chronic disease. The interplay of human genetic variation and environmental factors will make identifying causative genes and nutrients a formidable, but not intractable, challenge. We provide specific recommendations for how to best meet this challenge and discuss the need …
BIO Bragg gratings on microfibers for label-free biosensing
2021
[EN] Discovering nanoscale phenomena to sense biorecognition events introduces new perspectives to exploit nano science and nanotechnology for bioanalytical purposes. Here we present Bio Bragg Gratings (BBGs), a novel biosensing approach that consists of diffractive structures of protein bioreceptors patterned on the surface of optical waveguides, and tailored to transduce the magnitude of biorecognition assays into the intensity of single peaks in the reflection spectrum. This work addresses the design, fabrication, and optimization of this system by both theoretical and experimental studies to explore the fundamental physicochemical parameters involved. Functional biomolecular gratings ar…
Influence of the anisotropy of sisal fibers on the mechanical properties of high performance unidirectional biocomposite lamina and micromechanical m…
2021
Abstract High performance biocomposites reinforced by sisal fibers, are between the most promising materials that could be used in various fields, from automotive to civil constructions, thanks to their good mechanical performance, as well as to the low cost and the great availability of the fiber. Nevertheless, at present their practical use is prevented by the limited knowledge of their mechanical performance. The results of the present study have shown that the intimate fibrillar structure of the sisal fiber is associated with a high anisotropy involving not only the elastic parameters, but also the damage processes with typical fiber splitting phenomena, that influence noticeably the bi…
Influence of Ce codoping and H2 pre-loading on Er/Yb-doped fiber: Radiation response characterized by Confocal Micro-Luminescence
2011
International audience; Confocal microscopy luminescence measurements were applied to study the X-ray radiation response of Er/Yb-doped optical fibers in connection with H2 pre-loading and with the addition of another lanthanide element (Cerium) in the core composition. Laser excitations at 488 nm and 325 nm allow deriving the emission and absorption pattern of Er3+, the latter derived from the dips appearing in a wide luminescence band related to defects in silica. We found that the luminescence spectrum of the X-irradiated Er/Yb-doped core fiber evidences an increase in the emission intensity around 520 and 660 nm; in contrast, no changes are induced by radiation neither after H2 pre-load…
Giant subcutaneous lipomatosis in Myoclonic Epilepsy with Ragged Red Fibers syndrome: The first literature report of “laparoscopic” excision
2020
Background MERRF (Myoclonic Epilepsy with Ragged Red Fibers) is a rare multisystem clinical disorder due to a pathogenic variant of the mitochondrial DNA. Rare symptoms of MERRF include multiple systemic lipomatosis with symmetric uncapsulated lipomas occurs generally on the posterior cervical region and upper back. Methods We report the clinical case of a 46 years-old Caucasian man with MERRF syndrome who presented with MSL on the right cervical region. We decided to perform a mini-invasive approach using laparoscopic instruments. We performed a 10-mm incision about 5 cm under the mass and conducted a blunt dissection of the subcutaneous plane. Then we positioned a 10-mm port and started C…
Distillation and stripping pilot plants for the JUNO neutrino detector: Design, operations and reliability
2019
Abstract This paper describes the design, construction principles and operations of the distillation and stripping pilot plants tested at the Daya Bay Neutrino Laboratory, with the perspective to adapt these processes, system cleanliness and leak-tightness standards to the final full scale plants to be used for the purification of the liquid scintillator of the JUNO neutrino detector. The main goal of these plants is to remove radio impurities from the liquid scintillator while increasing its optical attenuation length. Purification of liquid scintillator will be performed with a system combining alumina oxide, distillation, water extraction and steam (or N 2 gas) stripping. Such a combined…
Infraglottic airway devices and techniques.
2005
Airway management involves far more than just proficiency with tracheal intubation techniques. There are several infraglottic techniques available and the method chosen will depend on the accessibility of equipment, the level of training and expertise, and the patient's specific injury or disease. Endotracheal intubation is most commonly performed by direct laryngoscopy. Several modifications of laryngoscope blades and a variety of adjuncts such as bougies may help to accomplish even a difficult airway. Rigid intubation fibrescopes do improve the view of the larynx, especially in patients with difficult anatomy. They also permit tracheal intubation with less head and cervical spine movement…
Remote Photoplethysmography for Evaluation of Cutaneous Sensory Nerve Fiber Function
2021
About 2% of the world’s population suffers from small nerve fiber dysfunction, neuropathy, which can result in severe pain. This condition is caused by damage to the small nerve fibers and its assessment is challenging, due to the lack of simple and objective diagnostic techniques. The present study aimed to develop a contactless photoplethysmography system using simple instrumentation, for objective and non-invasive assessment of small cutaneous sensory nerve fiber function. The approach is based on the use of contactless photoplethysmography for the characterization of skin flowmotions and topical heating evoked vasomotor responses. The feasibility of the technique was evaluated on volunt…
Observability of the Risken–Nummedal–Graham–Haken instability in Nd:YAG lasers
2003
Multilongitudinal mode instability in ring Nd:YAG lasers is theoretically analyzed. After we review the way in which the standard two-level laser theory applies to this laser we extend the theoretical treatment to include transverse effects. We do this by taking into account the finite transverse section of the active medium and by assuming a Gaussian transverse distribution for the intracavity field. Finally we demonstrate that multimode emission develops whenever the intracavity field waist diameter is almost equal to the active rod diameter. We conclude that continuous-wave diode-pumped Nd:YAG lasers with low cavity losses are good candidates for the observation of the Risken–Nummedal–Gr…