1,357,434 research outputs found
La casa dell'architetto: Torino-Maggiora
No full textLe due case di Antonelli, l'immobile di via Vanchiglia a Torino e la villa paterna a Maggiora, rappresentano il tema della casa dell'architetto in una accezione particolare: più che di casa-studio si potrebbe parlare per entrambe, a diverso titolo, di "casa-laboratorio", nel senso che Antonelli continua a lavorarci ininterrottamente nel tempo, anche a costruzione ultimata, utilizzandole come cantiere aperto di sperimentazione di nuove soluzioni costruttive e architettonich
Modelling of antenna radiation pattern of a re-entry vehicle in presence of plasmaIEEE Antennas and Propagation Society Symposium, 2004.
No full textAnalisi strutturale-cinematica di artroprotesi di ginocchio mediante modelli FEM parametrici
No full textThis work represents a first investigation into a possible new approach for the design optimization of knee prostheses. The integration of a user subroutine into a commercial finite element program allowed for a structural-kinematic model of the joint. The subroutine reproduces the kinematics of the joint as described by an anatomical model. Starting from the geometry of a commercial prosthesis, different finite element models were designed. The models differ for the degree of conformity of the contact. The analysis showed a reduction of the maximum compressive stress by 15% as compared to the commercial prosthesis. At higher degrees of conformity, the compliance of the surface does not allow for a correct joint kinematics. Results obtained for the size and location of the contact area as the flexion angle increases were found to agree substantially with the experimental data of a previous wor
Evaluation of the influence of the main plasma density parameters on antenna coupling and radio frequency potentials with TOPICA code
No full textThe successful design of an ion cyclotron antenna mainly relies on the capability of accurately predicting its behavior both in terms of input parameters, and therefore power coupled to plasma, and radiated fields. All these features essentially depend on the antenna itself (its geometry, the matching and tuning systems) and, obviously, on the faced loading. In this paper a number of plasma profiles is analysed with the help of the TOPICA code, a predictive tool for the design and optimization of radio frequency (RF) launchers in front of a plasma, in order to understand which plasma parameters have the most significant influence on the coupling performances of a typical IC antenna
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A revolutionary concept to improve the efficiency of IC antennas
No full textThe successful design of an Ion Cyclotron (IC) antenna mainly relies on the capability of coupling high power to the plasma (MW), feature that is currently reached by allowing rather high voltages (tens of kV) on the unavoidable unmatched part of the feeding lines. This requirement is often responsible of arcs along the transmission lines and other unwanted phenomena that considerably limit the usage of IC launchers. In this work, we suggest and describe a revolutionary approach based on high impedance surfaces, which allows to increase the antenna radiation efficiency and, hence, to highly reduce the imposed voltages to couple the same level of power to the plasma. High-impedance surfaces are periodic metallic structures (patches) displaced usually on top of a dielectric substrate and grounded by means of vertical posts usually embedded inside a dielectric, in a mushroom-like shape. In terms of working properties, high impedance surfaces are electrically thin in-phase reflectors, i.e. they present a high impedance, within a given frequency band, such that the image currents are in-phase with the currents of the antenna itself, thus determining a significant efficiency increase. While the usual design of a high impedance surface requires the presence of a dielectric layer, some alternative solutions can be realized in vacuum, taking advantage of double layers ofmetallic patches. After an introductory part on the properties of high impedance surfaces, this work documents both their design by means of numerical codes and their implementation on a scaled mock-u
ICRH System for the Ignitor Experiment21st IEEE/NPS Symposium on Fusion Engineering SOFE 05
No full textA DEMO relevant fast wave current drive high harmonic antenna exploiting the high impedance technique
No full textIon Cyclotron (IC) antennas are routinely adopted in most of the existing nuclear fusion experiments, even though their main goal, i.e. to couple high power to the plasma (MW), is often limited by rather severe drawbacks due to high fields on the antenna itself and on the unmatched part of the feeding lines. In addition to the well exploited auxiliary ion heating during the start-up phase, some non-ohmic current drive (CD) at the IC range of frequencies may be explored in view of the DEMO reactor. In this work, we suggest and describe a compact high frequency DEMO relevant antenna, based on the high impedance surfaces concept. High-impedance surfaces are periodic metallic structures (patches) usually displaced on top of a dielectric substrate and grounded by means of vertical posts embedded inside the dielectric, in a mushroom-like shape. These structures present a high impedance, within a given frequency band, such that the image currents are in-phase with the currents of the antenna itself, thus determining a significant efficiency increase. After a general introduction on the properties of high impedance surfaces, we analyze, by means of numerical codes, a dielectric based and a full metal solution optimized to be tested and benchmarked on the FTU experiment fed with generators at 433MH
A revolutionary concept to improve the efficiency of ion cyclotron antennas
No full textThe successful design of an ion cyclotron (IC) antenna mainly relies on the capability of coupling high power to the plasma (MW), feature that is currently reached by allowing rather high voltages (tens of kV) on the unavoidable unmatched part of the feeding lines. This requirement is often responsible of arcs along the transmission lines and other unwanted phenomena, such as rectification discharges or hotspots, that considerably limit the usage of IC launchers. In this work, we suggest and describe a revolutionary approach based on high impedance surfaces, which allows to increase the antenna radiation efficiency and, hence, to highly reduce the imposed voltages to couple the same level of power to the plasma. High-impedance surfaces are periodic metallic structures (patches) displaced usually on top of a dielectric substrate and grounded by means of vertical posts usually embedded inside a dielectric, in a mushroom-like shape. In terms of working properties, high impedance surfaces are electrically thin in-phase reflectors, i.e., they present a high impedance, within a given frequency band, such that the image currents are in-phase with the currents of the antenna itself, thus determining a significant efficiency increase. While the usual design of a high impedance surface requires the presence of a dielectric layer, some alternative solutions can be realised in vacuum, taking advantage of double layers of metallic patches. After an introductory part on the properties of high impedance surfaces, this work documents both their design by means of numerical codes and their implementation on a scaled mock-up
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