374 research outputs found
Acoustic excitations in glassy sorbitol and their relation with the fragility and the boson peak
No full textWe report a detailed analysis of the dynamic structure factor of glassy sorbitol by using inelastic X-ray scattering and previously measured light scattering data [B. Ruta, G. Monaco, F. Scarponi, and D. Fioretto, Philos. Mag. 88, 3939 (2008)]. The thus obtained knowledge on the density-density fluctuations at both the mesoscopic and macroscopic length scale has been used to address two debated topics concerning the vibrational properties of glasses. The relation between the acoustic modes and the universal boson peak (BP) appearing in the vibrational density of states of glasses has been investigated, also in relation with some recent theoretical models. Moreover, the connection between the elastic properties of glasses and the slowing down of the structural relaxation process in supercooled liquids has been scrutinized. For what concerns the first issue, it is here shown that the wave vector dependence of the acoustic excitations can be used, in sorbitol, to quantitatively reproduce the shape of the boson peak, supporting the relation between BP and acoustic modes. For what concerns the second issue, a proper study of elasticity over a wide spatial range is shown to be fundamental in order to investigate the relation between elastic properties and the slowing down of the dynamics in the corresponding supercooled liquid phase
3° Premio Ricerca & Innovazione Bic Lazio
No full textLa ricerca volge alla definizione delle caratteristiche fisico-chimiche e meccaniche di materiali compositi rinforzati con fibre naturali per applicazioni aeronautiche, in particolare per "Interiors"
Lifting line method for modelling covering and blanketing effects for yacht fleet race simulation
No full textAn approach is presented that can be used to enhance the realism of yacht fleet race simulations. The wake of an upwind sailing yacht is represented as a single heeled horseshoe vortex (and image) system. At each time step changes in vortex strength are convected into the wake as a pair of vortex line elements. These subsequently move in accordance with the local wind, self-induced velocity and velocity induced by the presence of the wakes of other yachts. An empirical based decay factor is used to eventually remove the far wake. A synthesis of sail yacht wake representations based on detailed 3D Reynolds Averaged Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) calculations with wind tunnel test results are used to capture the initial strength of the combined main-jib vortex system and its vertical height. These were based on a typical upwind sail arrangement for a range of heel angles and in-line calculations for a pair of yachts separated by three boat lengths. This paper details the basis of the validated CFD results for a yacht at heel and the analysis of the CFD results to provide an approximate single line vortex method for the yacht. The developed algorithm will eventually run within the Robo-Race which is a real-time yacht race strategy analysis tool based on MATLAB®-Simulink® developed at the University of Southampton
[Review of 87 cases of scoliosis surgically treated].
No full textThe authors compared the results and complications in surgical treatment of idiopathic scoliosis with Harrington's rod instrumentation with subtrasversal wires in dorsal treat. A research on 87 cases operated on for idiopathic scoliosis from 1987 to 1995 is carried out. The 87 cases include 65 females and 25 males, 16 years old in average (range, 11 to 30). The curvature in Cobb's degrees and rotation of vertebrae with Raimondi's method on radiographs take just before, 15 days later and an year later on operation was measured. The patients have been divided into two groups: the first of 77 patients operated with Harrington's rod instrumentation; the second of 10 patients operated with Harrington's rod instrumentation and subtrasversal wires. In a general analysis without taking in to consideration the type and the seriousness of curvature it was obtained a better correction and derotation of vertebrae in patients of second group. The same group with wires had obtained a better correction and derotation of vertebrae in dorsal scoliosis from 40 degrees to 60 degrees and in the double scoliosis, while the first group obtained better results in dorsal scoliosis from 60 degrees to 80 degrees and in derotation of vertebrae on dorsal treat of double scoliosis. One case of pseudarthrosis in every group was observed. Any neurological complication were observed. The conclusions is drawn that the application of subtrasversal wire improves the Harrington's technique for the correction and derotation of dorsal and double scoliosis without neurological complications sometimes present with subliminar wires
Persistence and detoxification of Pretilachlor and Fenclorim in rice (Oryza sativa)
No full textThe contents and persistence of pretilachlor (P) and of the safener
fenclorim (F) in rice treated with P, F and their mixture were investigated
in relation to the expression of glutathione-S-transferase (GST) activity
in response to treatments. F failed to reduce the accumulation of P, however
it was able to reduce its persistence in rice shoots. On the other hand,
while P did not reduced F persistence, it determined a greater than two-fold
F accumulation in plants. Therefore, a detoxification mechanism common to
the two compounds but favourable to P was hypothesised. This mechanism
consists in an activation of GST activity toward P as substrate [GST(P)]
in response to all treatments. The activation levels were found to be
proportional to the amount of persistent P and F, and to be additive
following the P-F mixture treatment. The kinetic parameters V
and K of GST(P) were increased and decreased, respectively, in rice shoots
treated with P, F and particularly with P-F mixture. Therefore, a defence
mechanism toward P, consisting in an increased expression of GST(P) in rice
plant, both as the global amount of the enzyme in the protein “pull” and the
induction of the enzyme isoforms more sensitive to P, in response to all
treatments, especially the P-F mixture treatment, is confirmed. This finding
is consistent with the observed effect of F on P persistence and detoxification
in the rice shoots.Persistance et détoxication du pretilachlore et du fenclorim dans
le riz (Oryza sativa). On a étudié la teneur et la persistence du
pretilachlore (P) et du fenclorim (F), un antidote, dans le riz traité
avec P, F et un mélange des deux par référence à l'activité de la
glutathion-S-transférase (GST) en réponse aux traitements en question.
F n'a pas réussi à réduire l'accumulation de P, mais a pu réduire sa
persistance dans les pousses de riz. D'autre part, P n'a pas réduit
la persistance de F, mais a déterminé une accumulation plus que double
de F dans les plantes. Donc a-t-on soulevé l'hypothèse d'un mécanisme
de détoxication commun aux deux composés, mais favorable à P.
Ce mécanisme consiste en une activation de l'activité GST à l'égard
de P comme substrat [GST(P)] en réponse à tous les traitements. On a
relevé que les niveaux d'activation étaient proportionnels à la quantité
de P et F persistants, et additifs dans le cas du traitement avec le
mélange P-F. Les paramètres cinétiques V et K
de [GST(P)] ont été respectivement augmentés et diminués dans les pousses
de riz traitées avec P, F et particulièrement avec le mélange P-F. On a eu donc
confirmation d'un mécanisme de défense à l'égard de P, consistant
en une expression accrue de [GST(P)] dans la plante de riz, en ce qui
concerne tant la quantité globale de l'enzyme dans le “ pull ” protéique
que l'induction des isoformes enzymatiques plus sensibles à P, en réponse
à tous les traitements et surtout au traitement à base de mélange P-F.
Ce résultat concorde avec ce qui a été observé quant à l'effet de F sur
la persistance et la détoxication de P dans les pousses de riz
VALUTAZIONE DEL DANNO IN TEMPO REALE SU ELEMENTI STRUTTURALI IN COMPOSITO AUTODIAGNOSTICANTI IN AMBIENTE AEROSPAZIALE
No full textViewing temporal trends of biotic interactions in the light of spatial variation: parasite prevalence in modern northern Adriatic bivalves.
No full textReactive and Proactive Approaches: Tutorials and Example
No full textBayesian inference-based dynamic risk assessment (BIDRA) and the risk barometer represent two different approaches that may be adopted for dynamic evaluation of accident frequency. BIDRA is a methodology for reactive risk assessment based on Bayesian inference, whereas the risk barometer is based on real-time indicator monitoring aiming to support proactive assessment of risk. This chapter illustrates two tutorials for the application of the BIDRA and risk barometer techniques. Moreover, application to the same representative case is performed by simulating the inputs for the methodologies: past near misses and accidents for BIDRA, and technical, operational, and organizational indicator trends for the risk barometer. This example aims to highlight similarities and differences and provides support for the selection of methods
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