Search results for "fiber"
showing 10 items of 2343 documents
Design of Radiation-Hardened Rare-Earth Doped Amplifiers through a Coupled Experiment/Simulation Approach
2013
International audience; We present an approach coupling a limited experimental number of tests with numerical simulations regarding the design of radiation-hardened (RH) rare earth (RE)-doped fiber amplifiers. Radiation tests are done on RE-doped fiber samples in order to measure and assess the values of the principal input parameters requested by the simulation tool based on particle swarm optimization (PSO) approach. The proposed simulation procedure is validated by comparing the calculation results with the measured degradations of two amplifiers made with standard and RH RE-doped optical fibers, respectively. After validation, the numerical code is used to theoretically investigate the …
Studien zum Vorgang der Wasserstoffübertragung, 39. Langlebige Hydrierkatalysatoren durch kovalente Verknüpfung von Phosphin-Rhodium-Komplexen an Aer…
1976
Homogene Phosphin-Rhodium-Katalysatoren werden durch kovalente Bindung an ‘Aminoaerosil’ heterogenisiert. Die Abhangigkeit der Hydriergeschwindigkeit von der Entfernung der aktiven Zentren zur Oberflache, von der Temperatur, vom Losungsmittel und von der Struktur der eingesetzten Olefine wird untersucht. Studies on the Occurrence of Hydrogen Transfer, 39. — Long-Lived Hydrogenation Catalyst by Covalent Fixation of Phosphine-Rhodium-Complexes on the Surface of Aerosil 200 The covalent binding of hitherto homogeneous phosphine-rhodium catalysts to “Amino-aerosil” is described. The dependence of the rate of catalysed hydrogenation upon the distance between the reaction centre and the silica su…
Thermal characterisation of Bio Based Building Materials
2006
This paper describes how the characterization of indigenous renewable biomass sources that are applicable for making bio-based building (BBB) materials is crucial as it can significantly affect the cost of production and the quality of material. Nowadays, in any specific area, wide ranges of biomass sources are usually available but only a few sources may be suitable for making BBB material. Therefore the suited sources should be determined. In this paper, the use of BBB materials is focused on Insulation Materials which are widely used in the buildings. Compared with currently used materials, these materials are bio-degradable. Insulation material with a good energy-adsorbing property and …
The effect of reaction conditions on the chain end structure and functionality during dehydrochlorination oftert-chlorine-telechelic polyisobutylene …
1998
Dehydrochlorination of tert-chlorine-telechelic polyisobutylene with potassium tert-butoxide in refluxing tetrahydrofuran is quantitative after 22 h, but results in ca. 3% endo olefin chain ends which are not reactive in some subsequent functionalization reactions. The formation of these undesired structures is most likely due to simultaneous thermally induced HCl loss. Lower temperatures and longer reaction times led to exclusive formation of external double bonds in some cases but to incomplete dehydrochlorination.
Potassium demineralization of coconut fiber via combined hydrothermal treatment and washing: Effect on pyrolysis kinetics, mechanisms, and bio-oil co…
2021
Abstract Producing clean energy from waste biomass via pyrolysis is critical in reducing dependence on fossil fuels and alleviating their environmental impacts. Inherent potassium in low energy density coconut fibers reduces bio-oil yield and compromises bio-oil quality and the integrity of reactors within which pyrolysis occurs. The effect of consecutive hydrothermal treatment (180°C-220 °C) and water washing on coconut fiber demineralization, pyrolysis behavior, and bio-oil composition was investigated. Chemical fractionation method classified the most occurring inorganic (potassium) as ~76% water-soluble, ~19% ion-exchangeable, and ~5% acid-soluble species. Demineralization results show …
Preferential Type II Muscle Fiber Damage From Plyometric Exercise
2012
Context: Plyometric training has been successfully used in different sporting contexts. Studies that investigated the effect of plyometric training on muscle morphology are limited, and results are controversial with regard to which muscle fiber type is mainly affected. Objective: To analyze the skeletal muscle structural and ultrastructural change induced by an acute bout of plyometric exercise to determine which type of muscle fibers is predominantly damaged. Design: Descriptive laboratory study. Setting: Research laboratory. Patients or Other Participants: Eight healthy, untrained individuals (age = 22 ± 1 years, height = 179.2 ± 6.4 cm, weight = 78.9 ± 5.9 kg). Intervention(s): Partici…
Positioning of the cross-stitch on the modified Kessler core tendon suture
2018
[EN] Cryopreserved human tendons were sutured with different variations of a modified Kessler-type grasping suture in a series of different designs in order to assess the influence of the distance between the cross-stitch on the core suture (5 and 10 mm from the cut tendon edge) on the peripheral suture. An original mathematical model was employed to explain the mechanical behavior (strength, deformation, and distribution of load) of the different suture designs. The effect of the peripheral epitendinous suture, combined with the distance of the core suture, was evaluated. The variation of core suture distance had no relevant consequences on the overall resilience of the design. However, in…
Magnetic resonance imaging and optical coherence tomography correlations in multiple sclerosis beyond anatomical landmarks.
2020
Abstract Objective To investigate multiple sclerosis (MS) optical coherence tomography (OCT) cross-sectional correlations with central nervous system (CNS) magnetic resonance imaging (MRI). Material and methods Peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner (INL) and outer nuclear layer (ONL) of 54 relapsing remitting (RRMS) and 38 progressive (PMS, 9 primary and 29 secondary) patients were measured. With less than 3 months brain parenchymal fraction (BPF), spinal cord (SC), total gray matter (GM) and white matter volumes were calculated. Demographical and clinical data was compared according to the history of optic neuritis (H…
A novel automated segmentation method for retinal layers in OCT images proves retinal degeneration after optic neuritis.
2015
Aim The evaluation of inner retinal layer thickness can serve as a direct biomarker for monitoring the course of inflammatory diseases of the central nervous system such as multiple sclerosis (MS). Using optical coherence tomography (OCT), thinning of the retinal nerve fibre layer and changes in deeper retinal layers have been observed in patients with MS. Here, we first compare a novel method for automated segmentation of OCT images with manual segmentation using two cohorts of patients with MS. Using this method, we also aimed to reproduce previous findings showing retinal degeneration following optic neuritis (ON) in MS. Methods Based on a 5×5 expansion of the Prewitt operator to efficie…
OCT-Angiography evaluation of peripapillary microvascular changes after rhegmatogenous retinal detachment repair
2021
Purpose: To evaluate the radial peripapillary capillary plexus (RPCP) vessel density (VD) and the retinal nerve fiber layer (RNFL) thickness in eyes successfully treated with pars plana vitrectomy for primary rhegmatogenous retinal detachment. Methods: In this cross-sectional multicenter clinical study, eyes with a minimum 12-month follow-up were reexamined. The RPCP VD and RNFL thickness in the rhegmatogenous retinal detachment subfields of the affected eye (study group) were compared with the corresponding areas of the healthy fellow eyes (control group). Results: Fifty-three eyes were included in the study. A significantly lower RPCP VD and RNFL thickness were observed in those subfields…