Search results for "wave"
showing 10 items of 6009 documents
The Essential Oil Composition ofEryngium foetidumL. in South Vietnam Extracted by Hydrodistillation under Conventional Heating and Microwave Irradiat…
2008
Abstract Essential oils of Eryngium foetidum L. (Apiaceae) in the South Vietnam isolated by hydrodistillation under conventional heating or microwave irradiation showed somewhat similar in chemical compositions. The microwave method gave a higher extraction yield in a much shorter time frame than the conventional heating protocol. Noticeably, the oil obtained from the microwave method showed a stronger antimicrobial activity than the other. Among all parts of the plant, inflorescence contained the highest oil content, and three-month old plant material was found richest in oil content as well. Physical, chemical and antibacterial properties of the oil products isolated from both methods wer…
On the Computational Aspects of a Symmetric Multidomain Boundary Element Method Approach for Elastoplastic Analysis
2011
The symmetric boundary element method (SBEM) is applied to the elasto-plastic analysis of bodies subdivided into substructures. This methodology is based on the use of: a multidomain SBEM approach, for the evaluation of the elastic predictor; a return mapping algorithm based on the extremal paths theory, for the evaluation of inelastic quantities characterizing the plastic behaviour of each substructure; and a transformation of the domain inelastic integrals of each substructure into corresponding boundary integrals. The elastic analysis is performed by using the SBEM displacement approach, which has the advantage of creating system equations that only consist of nodal kinematical unknowns…
Combined effects of heatwaves and micropollutants on freshwater ecosystems: Towards an integrated assessment of extreme events in multiple stressors …
2022
Freshwater ecosystems are strongly influenced by weather extremes such as heatwaves, which are predicted to increase in frequency and magnitude in the future. In addition to these climate extremes, the freshwater realm is impacted by the exposure to various classes of chemicals emitted by anthropogenic activities. Currently, there is limited knowledge on how the combined exposure to heatwaves and chemicals affects the structure and functioning of freshwater ecosystems. Here, we review the available literature describing the single and combined effects of heatwaves and chemicals on different levels of biological organization, to obtain a holistic view of their potential interactive effects. …
Study of Redox Processes in Zeolite Y-Associated 2,4,6-Triphenylthiopyrylium Ion by Square Wave Voltammetry
2003
The electrochemical responses of 2,4,6-triphenylthiopyrylium ion (TTP+) in solution and attached to zeolite Y (TTP@Y) are described using cyclic and square wave voltammetries upon immersion of zeolite-modified polymer film electrodes in MeCN (LiClO4, Et4NClO4, and BuN4PF6 electrolytes) and aqueous (LiNO3, NaNO3, and KNO3 electrolytes) media. The electrochemistry of TTP@Y in contact with Bu4NPF6/MeCN is identical to that of TTP(BF4) in solution, with reduction processes at −0.25, −0.74, and −1.36 V vs SCE, and oxidation steps at +0.85 and +1.11 V. This response differs from those obtained for TTP@Y in Et4NClO4/MeCN and LiClO4/MeCN electrolytes. In contact with aqueous electrolytes, TTP@Y dis…
Electrochemistry of copper complexes with macrocyclic polyamines containing pyrazole units.
2006
The voltammetric behaviour of bi- and mono-nuclear complexes formed in solution by Cu(2+) with three polyazacyclophanes containing pyrazole units in aqueous solution is described. Cyclic and square wave voltammetric responses at glassy carbon electrodes indicate that the reduction of copper-macrocycle complexes in solution takes place in two successive one-electron per Cu transfer processes coupled with preorganization and protonation reactions that mimic the behaviour of superoxide dismutase. The electrochemistry of ternary Cu(2+)-receptor-dopamine complexes exhibits significant differences with respect to the protection of the neurotransmitter from post-electron transfer cyclization react…
The Mediterranean Sea and the Gulf of Cadiz as a natural laboratory for paleotsunami research: Recent advancements
2021
International audience; After the 2004 Indian Ocean (IOT) and the 2011 Tohoku-oki tsunamis, new research in tsunami-related fields was strongly stimulated worldwide and also in the Mediterranean. This research growth yields substantial advancements in tsunami knowledge.Among these advancements is the “Paleotsunami” research that has marked particular progress on the reconstruction of the tsunami history of a region. As an integration of the historical documentation available in the Mediterranean and the Gulf of Cadiz areas, geological and geoarchaeological records provide the insights to define the occurrence, characteristics, and impact of tsunamis of the past. Here, we present the recent …
Space charge and induced dipole relaxation in solid electrolytes
1996
The space charge relaxation and induced dipole relaxation in solid electrolytes is discussed. The di-electric responses of these relaxations gives a satisfactory fit to the universal conductivity behaviours in the frequency range from DC to infrared.
Influence of the metabolic syndrome on aortic stiffness in never treated hypertensive patients
2004
Summary Background and aim Metabolic syndrome (MS) carries an increased risk for cardiovascular events and there is a growing awareness that large artery stiffening is a powerful predictor of cardiovascular morbidity and mortality. Little is known about the relationship of MS with aortic stiffness. The aim of our study was to analyze, in patients with essential hypertension, the influence of MS, defined according to the criteria proposed by the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP-ATP III), on carotid–femoral pulse wave velocity (PWV), a measure of aortic stiffness. Methods N…
Stability of impulsive differential systems
2013
The asymptotic phase property and reduction principle for stability of a trivial solution is generalized to the case of the noninvertible impulsive differential equations in Banach spaces whose linear parts split into two parts and satisfy the condition of separation.
New Objective Refraction Metric Based on Sphere Fitting to the Wavefront
2017
Purpose. To develop an objective refraction formula based on the ocular wavefront error (WFE) expressed in terms of Zernike coefficients and pupil radius, which would be an accurate predictor of subjective spherical equivalent (SE) for different pupil sizes.Methods. A sphere is fitted to the ocular wavefront at the center and at a variable distance,t. The optimal fitting distance,topt, is obtained empirically from a dataset of 308 eyes as a function of objective refraction pupil radius,r0, and used to define the formula of a new wavefront refraction metric (MTR). The metric is tested in another, independent dataset of 200 eyes.Results. For pupil radiir0≤2 mm, the new metric predicts the equ…