Search results for " Axis"
showing 10 items of 188 documents
Wind tunnel testing, numerical analyses and shape optimization of a vertical axis wind turbine
2011
In this work the aerodynamic efficiency of a small commercial vertical axis wind turbine is investigated experimentally and numerically. The turbine is a Darrieus type with three vertical airfoil blades having helical twist of 78 degrees, height 1.45m and diameter of 1.45m. The airfoils have a chord of 222 mm and a thickness of 35 mm. The experimental studies were made in a wind tunnel where a hot-wire anemometer was used to measure the wind speed. The power curves of the turbine were extracted using a generator connected with an inverter able to vary the resistant moment applied to the turbine and to measure its resulting angular speed. The energy produced by the turbine itself at various …
All’origine della deissi indoeuropea. Un approccio linguistico cognitivo
2020
This paper focuses on the existence of temporal deixis in Indo-European, questioning the traditional view according to which metaphors of time in ancient Indo-European languages originated from projecting the human body coordinates onto space. In particular, it aims at interpreting data from historical-comparative linguistics by using the cognitive linguistic framework, without disregarding the most recent results from typological studies, spatial language acquisition, and neurolinguistic research on spatiotemporal deixis. Contrary to what previously assumed, the comparative analysis between the Rigveda and the Homeric poems shows that earlier spatial metaphors of time are still deictically…
Variable fractional Fourier processor: a simple implementation
1997
A new set of optical implementations of the fractional Fourier transform (FRT) is developed by use of Wigner matrix algebra. The reinterpretation of some elementary operations that synthesize a rotation in the phase-space domain allows us to propose a lensless setup for obtaining the FRT. This compact configuration is also very flexible, because the fractional degree of the transformation can be varied continuously by shifting the input and the output planes along the optical axis by proper amounts. The above results permit one to build an optical FRT processor formed by two FRT systems in cascade, with a spatial filter between them. We present the design of such a variable FRT processor, w…
Magnetic resonance imaging of the siliceous skeleton of the demosponge Lubomirskia baicalensis
2005
The skeletal elements (spicules) of the demosponge Lubomirskia baicalensis were analyzed; they are composed of amorphous, non-crystalline silica, and contain in a central axial canal the axial filament which consists of the enzyme silicatein. The axial filament, that orients the spicule in its longitudinal axis exists also in the center of the spines which decorate the spicule. During growth of the sponge, new serially arranged modules which are formed from longitudinally arranged spicule bundles are added at the tip of the branches. X-ray analysis revealed that these serial modules are separated from each other by septate zones (annuli). We describe that the longitudinal bundles of spicule…
Optical near-field microscopy of light focusing through a photonic crystal flat lens
2008
We report here the direct observation by using a scanning near-field microscopy technique of the light focusing through a photonic crystal flat lens designed and fabricated to operate at optical frequencies. The lens is fabricated using a III-V semiconductor slab, and we directly visualize the propagation of the electromagnetic waves by using a scanning near-field optical microscope. We directly evidence spatially, as well as spectrally, the focusing operating regime of the lens. At last, in light of the experimental scanning near-field optical microscope pictures, we discuss the lens ability to focus light at a subwavelength scale.
Tutela e sicurezza del lavoro tra centro e periferia: la sicurezza sui luoghi di lavoro
2013
Il saggio prende in esame la complessa questione del riparto di competenze tra Stato e Regioni alla luce del Titolo V della Costituzione in materia di salute e sicurezza sui luoghi di lavoro. Il riparto di competenze tra centro e periferia è stato oggetto di una limitata analisi da parte della dottrina e della giurisprudenza, che si sono concentrate in particolare sulla disciplina del mercato del lavoro. L’Autore descrive un sistema multilivello, caratterizzato dalla compresenza di fonti nazionali e regionali, della contrattazione collettiva, nonché di codici di condotta. Sulla scorta di una ricostruzione del quadro normativo e dei percorsi della giurisprudenza, il saggio propone una lettur…
PM—Power and Machinery
2001
Abstract In both the OECD Code and the EC Directive for testing dual-pillar front-mounted roll-over protection structures for narrow track width tractors, a non-continuous rolling preliminary test in case of lateral overturning is provided. This test can be simulated with a computer programme. The role of the tyres (and also of the rims) in the lateral overturning of narrow tractors is very important. Frequently the same tractor can be alternatively equipped with four, five, or more different tyre combinations, which can vary its total mass, width, centre of gravity position and moment of inertia about its longitudinal axis. According to the Standards the preliminary test must be carried ou…
Le solo imprévu : l?atelier d?improvisation comme lieu d?échanges entre cultures d?audition
2021
Starting from sociologist Anne-Marie Green?s idea of ?common space?, and from Hans Robert Hauss? reception theory, the improvisation workshop is thought to be a way of transforming the practices of reception, in order to modify the nature of the culture of listening of each listener. Four research axis are, then, proposed, from the validation of the personal experience of the participants to the reception of the instant?s surprise as a factor of education, including the research of communicational tools specific to reception of music, capable of captivating the listeners with the original aspects of the unknown musical territories.
Organizational and activational effects of testosterone in two populations with high androgenization susceptibility = Efectos organizadores y activad…
2013
Los esteroides sexuales como la testosterona (T) producen una organización y/o modificaciones relativamente permanentes de la estructura y función del sistema nervioso central. Una alta exposición prenatal a la T podría estar relacionada con una mayor sensibilidad a los efectos activadores de dicha hormona durante la edad adulta. Por otra parte, las fluctuaciones en los niveles endógenos de T pueden modificar transitoriamente las capacidades socio-cognitivas. Así, la conducta y los procesos cognitivos podrían ser el resultado de la interacción entre los efectos hormonales organizadores y activadores. La T podría ser considerada como un predictor de rasgos masculinizados tales como los rasgo…
VEGF and Notch Signaling in Angiogenesis
2015
The vascular system is responsible for providing every cell in vertebrate organisms with a sufficient supply of oxygen and nutrients, allowing waste disposal as well as transmitting immune responses among other functions. Thus, every tissue and organ requires an efficient network of blood vessels, which can be formed de novo (vasculogenesis) or from existing vessels (angiogenesis). The onset of the latter, namely endothelial cell (EC) sprouting, is the focus of this chapter. EC sprouting starts with the differentiation of ECs into guiding tip cells and proliferative stalk cells that form the growing sprout and it ends with the so-called anastomosis, when the sprout fuses with another sprout…