95 research outputs found
Global characterization of innovative polymeric micro-heat sink
No full textDuring the space missions, the problems related to the thermal conditioning of devices, to the personnel comfort and to the thermomechanical stresses are known and important. Furthermore for a space mission certain priorities are stressed, such as the small dimension and the lightness of thermal equipments. Due to the presence of high temperature gradients, which straightforwardly implies significant heating/cooling powers, these characteristics are sometimes difficult to obtain. Besides, miniaturized heat exchangers will have a terrestrial large industrial diffusion for electronic component cooling, in propulsion and in the power production for microsatellites, spacecrafts and airplanes and in many biomedical applications, for example, in cloth conditioning in harsh environmental conditions. Given the great value of the ratio between exchanging surface and volume of these systems, the specific thermal power per unit volume can reach extremely high values (1000 kW/m2 is a possible target). The low density, high elasticity and mechanical resistance suggest that the development of a new technology for heat sink, based on a sheet of polymeric microtubes (with a overall thickness of some tenths of millimeter) could be of great interest for space and terrestrial applications. A polymeric micro-heat sink was designed and built. Many technical problems were solved and a first prototype is available. The micro-heat sink was configured to cool an electric resistance with nitrogen and helium. An experimental set-up was built and some preliminary tests are running. For gas flow rates ranging from 3 to 26 Nl/min, a maximum heat flux of about 14 kW/m2 has been reached. The heat-sink has a surface of 6cm2 and a weight of 0.25g. The maximum pressure drop reached 3 bar. Different polymers were considered in order to test the heat sink thermal and mechanical resistances
Expression and phylogenetic analyses of the Gel/Gas proteins of Tuber melanosporum provide insights into the function and evolution of glucan remodeling enzymes in fungi
No full textThe Î2(1,3)-glucanosyltransferases of the GH72 family are redundant enzymes that are essential for the formation and dynamic remodeling of the fungal wall during different stages of the life cycle. Four putative genes encoding glycosylphosphatidylinositol (GPI)-anchored Î2(1,3)-glucanosyltransferases, designated TmelGEL1, TmelGEL2, TmelGEL4 and TmelGAS4, have been annotated in the genome of Tuber melanosporum, an ectomycorrhizal fungus that also produces a hypogeous fruiting body (FB) of great commercial value (black truffle). This work focuses on the characterization and expression of this multigene family by taking advantage of a laser microdissection (LMD) technology that has been used to separate two distinct compartments in the FB, the hyphae and the asci containing the ascospores. Of the four genes, TmelGEL1 was the most up-regulated in the FB compared to the free-living mycelium. Inside the FB, the expression of TmelGEL1 was restricted to the hyphal compartment. A phylogenetic analysis of the Gel/Gas protein family of T. melanosporum was also carried out. A total of 237 GH72 proteins from 51 Ascomycotina and 3 Basidiomycota (outgroup) species were analyzed. The resulting tree provides insight into the evolution of the T. melanosporum proteins and identifies new GH72 paralogs/subfamilies. Moreover, it represents a starting point to formulate new hypotheses on the significance of the striking GH72 gene redundancy in fungal biology. © 2013 Elsevier Inc
Design and testing of an active damping system for the reduction of vibrations induced by a rotating device on the ISS
No full textAntonacci F., Gambacorti-Passerini M.B. & Oggionni F. (a cura di), Educazione e terrorismo. Posizionamenti pedagogici, Milano: FrancoAngeli, 2019, pp. 151.
No full textLes composantes de la parole dans la caractérisation phonétique du locuteur : étude sur la complémentarité et la redondance des informations véhiculées
No full textThe decomposition of the speech signal into phonetically meaningful units allows the analysis of between- and within- speaker variations. These are components associated with characteristics whose nature relates to the physical, psychological and social aspects of a speaker. In this thesis, we compare perceptual characterisation results with a phonetic analysis and advanced modelling techniques through Convolutional Neural Networks (CNN).Clusterings’ analysis shows that the perceptual results are coherent with those obtained by the CNN and phonetic approaches, which supports the application of these methods in Phonetics. Our results highlight that spectrograms are the most accurate speech representation for speaker identification (96% correct answers on average). Higher formants and harmonics are more important in the characterisation of female voices. Whereas, voice quality characteristics, such as breathiness and hoarseness, play a major role in the characterisation of male speakers. The comparison between Mel Frequency Cepstral Coefficients (MFCC) and classical phonetic measurements is also examined. The MFCC are mainly linked to intensity and f in the characterisation of female speakers, while to the distributions of energy and low level spectral shape for male speakers.Our findings confirm the importance of describing the within-speaker variation for a more complete un- derstanding of between-speakers dierences.La décomposition du signal vocal en unités phonétiquement significatives permet d’analyser les variations inter- et intra- locuteur. Ces unités sont des composantes associées à des caractéristiques dont la nature est liée aux aspects physiques, psychologiques et sociaux d’un locuteur. Dans cette thèse, nous comparons une caractérisation perceptive, une analyse phonétique et des techniques de modélisation avancées par des réseaux de neurones à convolution (CNN).L’analyse des clusterings montre que les résultats perceptifs sont cohérents avec ceux obtenus par les approches CNN et phonétique, ce qui soutient leurs applications en phonétique. Nos résultats mettent en évidence que les spectrogrammes sont la représentation de la parole la plus précise pour l’identification des locuteurs (96% de bonnes réponses en moyenne). Les formants et des harmoniques plus élevés sont plus importants dans la caractérisation des voix féminines. En revanche, les caractéristiques de la qualité de la voix, telles que le soue et la raucité, jouent un rôle majeur dans la caractérisation des voix masculines. Le lien entre les coecients cepstraux à fréquence Mel (MFCC) et les mesures phonétiques classiques est également examiné. Les MFCC sont principalement liés à l’intensité et à f dans la caractérisation des voix féminines, tandis qu’aux distributions d’énergie et à la forme spectrale de bas niveau pour celle des voix masculines.Nos résultats confirment l’importance de la description de la variation intra-locuteur pour une compréhension plus complète des diérences entre locuteurs
Global characterization of innovative polymeric micro-heat sink
No full textDuring the space missions, the problems related to the thermal conditioning of devices, to the personnel comfort and to the thermomechanical stresses are known and important. Furthermore for a space mission certain priorities are stressed, such as the small dimension and the lightness of thermal equipments. Due to the presence of high temperature gradients, which straightforwardly implies significant heating/cooling powers, these characteristics are sometimes difficult to obtain. Besides, miniaturized heat exchangers will have a terrestrial large industrial diffusion for electronic component cooling, in propulsion and in the power production for microsatellites, spacecrafts and airplanes and in many biomedical applications, for example, in cloth conditioning in harsh environmental conditions. Given the great value of the ratio between exchanging surface and volume of these systems, the specific thermal power per unit volume can reach extremely high values (1000 kW/m2 is a possible target). The low density, high elasticity and mechanical resistance suggest that the development of a new technology for heat sink, based on a sheet of polymeric microtubes (with a overall thickness of some tenths of millimeter) could be of great interest for space and terrestrial applications. A polymeric micro-heat sink was designed and built. Many technical problems were solved and a first prototype is available. The micro-heat sink was configured to cool an electric resistance with nitrogen and helium. An experimental set-up was built and some preliminary tests are running. For gas flow rates ranging from 3 to 26 Nl/min, a maximum heat flux of about 14 kW/m2 has been reached. The heat-sink has a surface of 6cm2 and a weight of 0.25g. The maximum pressure drop reached 3 bar. Different polymers were considered in order to test the heat sink thermal and mechanical resistances
The construction of the Fiber-SiPM beam monitor system of the R484 and R582 experiments at the RIKEN-RAL muon facility
No full textThe scintillating fiber-SiPM beam monitor detectors, designed to deliver beam informations for the R484 and R582 experiments at the high intensity, low energy pulsed muon beam at the RIKEN-RAL facility, have been successfully constructed and operated. Details on their construction and first performances in beam are reported
MOSCAB: a geyser-concept bubble chamber to be used in a dark matter search
No full textThe MOSCAB experiment (Materia OSCura A Bolle) uses the “geyser technique”, a variant of the superheated liquid technique of extreme simplicity. Operating principles of the new dark matter detector and technical solutions of the device are reported in detail. First results obtained in a series of test runs taken in laboratory demonstrate that we have successfully built and tested a geyser-concept bubble chamber that can be used in particle physics, especially in dark matter searches, and that we are ready to move underground for extensive data taking
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