Search results for "Length"
showing 10 items of 2188 documents
Force Generation Profiles of Para-Nordic Sit-Skiers Representing Different Physical Impairments
2021
Abstract Purpose To biomechanically profile force generation connected to the complex role of the trunk in double poling in a representative sample of Para-Nordic sit-skiers. Methods Twelve male World Cup Para-Nordic sit-skiers (sport classes: LW10–12) were skiing on flat snow terrain at submaximal speed of 4.5 m/s (~ 73% maximum speed). 2D video (50 Hz) and pole force analyses (1000 Hz) were performed synchronously, examining angle, force and cycle characteristics to analyse the role of the trunk in generating propulsion. Results LW10–11.5 skiers lost between 21% and 4% propulsive force versus LW12 athletes only due to different geometrics of the trunk and pole angle at an equal axial pole…
Combined effect of turbulence and aerosol on free-space optical links
2017
[EN] Despite the benefits of free-space optical (FSO) communications, their full utilization is limited by the influence of atmospheric weather conditions, such as fog, turbulence, smoke, snow, etc. In urban environments, additional environmental factors such as smog and dust particles due to air pollution caused by industry and motor vehicles may affect FSO link performance, which has not been investigated in detail yet. Both smog and dust particles cause absorption and scattering of the propagating optical signal, thus resulting in high attenuation. This work investigates the joint impact of atmospheric turbulence and dust particle-imposed scattering on FSO link performance as part of the…
The influence of the propagation path length on the results of the time–frequency analysis of the acoustic emission generated by partial discharges i…
2006
The paper presents the measurement results of the acoustic emission (AE) signals generated by partial discharges (PDs) at various thickness of the oil insulation layer. For the AE signals registered the time - frequency analysis was carried out based on the use of the short-time Fourier transform (STFT). Two- and three-dimensional spectrograms of the power spectrum density and the amplitude spectrum were determined. The evaluation of the influence of the propagation path length of the AE signal on the results of the time - frequency analysis was performed through the analysis of the spectrograms determined.
Analysis of Fresnel Zone Plates Focusing Dependence on Operating Frequency
2017
[EN] The focusing properties of Fresnel Zone Plates (FZPs) against frequency are analyzed in this work. It is shown that the FZP focal length depends almost linearly on the operating frequency. Focal depth and focal distortion are also considered, establishing a limit on the frequency span at which the operating frequency can be shifted. An underwater FZP ultrasound focusing system is demonstrated, and experimental results agree with the theoretical analysis and simulations.
Pinhole Zone Plate Lens for Ultrasound Focusing
2017
[EN] The focusing capabilities of a pinhole zone plate lens are presented and compared with those of a conventional Fresnel zone plate lens. The focusing properties are examined both experimentally and numerically. The results confirm that a pinhole zone plate lens can be an alternative to a Fresnel lens. A smooth filtering effect is created in pinhole zone plate lenses, giving rise to a reduction of the side lobes around the principal focus associated with the conventional Fresnel zone plate lens. The manufacturing technique of the pinhole zone plate lens allows the designing and constructing of lenses for different focal lengths quickly and economically and without the need to drill new p…
Self-reported dependence on mobile phones in young adults: A European cross-cultural empirical survey
2017
Background and aims: Despite many positive benefits, mobile phone use can be associated with harmful and detrimental behaviors. The aim of this study was twofold: to examine (a) cross-cultural patterns of perceived dependence on mobile phones in ten European countries, first, grouped in four different regions (North: Finland and UK; South: Spain and Italy; East: Hungary and Poland; West: France, Belgium, Germany, and Switzerland), and second by country, and (b) how socio-demographics, geographic differences, mobile phone usage patterns, and associated activities predicted this perceived dependence.\ud \ud Methods: A sample of 2,775 young adults (aged 18–29 years) were recruited in different…
Utility of the polymerase chain reaction-restriction fragment length polymorphisms of the intergenic spacer region of the rDNA for characterizing Gib…
2004
Summary In the present report, a total of thirty-one isolates of Gibberella fujikuroi (Sawada) Wollenw. species complex of Fusarium (section Liseola) morphologically classified as F. moniliforme according to the taxonomy of Nelson, Toussoun and Marasas (1983) were analyzed for their ability to produce fumonisin B1 and fumonisin B2 by an optimized liquid chromatographic method. They were isolated from three hosts (Zea mays, Musa sapientum and Pinus pinea). The results indicate that M. sapientum is a preferential host for G. fujikuroi isolates with low or null capacity for producing fumonisins, while isolates from Z. mays and P. pinea are generally high fumonisin producers. The molecular char…
Characterization ofFusarium verticillioides strains by PCR-RFLP analysis of the intergenic spacer region of the rDNA
2005
Thirty-three Fusarium verticillioides strains from diverse origins and hosts have been analysed for fumonisin production and characterized in order (i) to detect the variability present in this species and (ii) to discriminate among isolates. The method used was a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) generated by restriction endonucleases applied to the IGS region (intergenic spacer of rDNA). All the F. verticillioides strains associated with crops produced fumonisins B1 and B2 except those isolated from banana. Analysis of the IGS region by PCR-RFLP proved to be useful to detect variability within F. verticillioides and allowed …
Fumonisin production by Gibberella fujikuroi strains fromPinus species
2003
Abstract Fumonisins are important mycotoxins basically produced by strains from the Gibberella fujikuroi species complex (with anamorphs in Fusarium genus) which contaminate food and feed products representing a risk to human and animal health. In this work, we report for the first time the fumonisin production of Fusarium moniliforme Sheldon strains associated to edible pine nuts of Pinus pinea. P. pinea is an important and widely distributed Pinus species in the Mediterranean area where their pine nuts are consumed raw or slightly processed in diverse food products. In this work, characterization and further identification of those strains were performed by polymerase chain reaction-restr…
Characterization of Fusarium spp. isolates by PCR-RFLP analysis of the intergenic spacer region of the rRNA gene (rDNA)
2004
In the present study, 44 Fusarium spp. isolates (5 Fusarium culmorum, 7 Fusarium graminearum, 1 Fusarium cerealis, 1 Fusarium poae, 26 Fusarium oxysporum, and 4 Gibberella fujikuroi species complex) were characterized morphologically, physiologically and genetically. All except one (Dutch Collection: CBS 620.72) were isolated from different hosts grown in various Spanish localizations. Morphological characterization was made according to macroscopic and microscopic aspects. Physiological characterization was based on their ability to produce zearalenone (ZEA) and type B trichothecenes (deoxynivalenol, nivalenol and 3-acetyldeoxynivalenol). ZEA was determined by liquid chromatography and tri…