6,864 research outputs found
Insight into CO2 dissociation in plasmas from numerical solution of a vibrational diffusion equation
The dissociation of CO2 molecules in plasmas is a subject of enormous
importance for fundamental studies and the recent interest in carbon capture
and carbon-neutral fuels. The vibrational excitation of the CO2 molecule plays
an important role in the process. The complexity of the present state-to-state
(STS) models makes it difficult to find out the key parameters. In this paper
we propose as an alternative a numerical method based on the diffusion
formalism developed in the past for analytical studies. The non-linear
Fokker-Planck equation is solved by the time-dependent diffusion Monte Carlo
method. Transport quantities are calculated from STS rate coefficients. The
asymmetric stretching mode of CO2 is used as a test case. We show that the
method reproduces the STS results or a Treanor distribution depending on the
choice of the boundary conditions. A positive drift, whose energy onset is
determined by the vibrational to translational temperature ratio, brings
molecules from mid-energy range to dissociation. The high-energy fall of the
distribution is observed even neglecting VT processes which are normally
believed to be its cause. Our study explains several puzzling features of
previous studies, provides new insights into the control of the dissociation
rate and a much sought compression of the required data for modeling
Mutual Inductance Route to Paramagnetic Meissner Effect in 2D Josephson Junction Arrays
We simulate two-dimensional Josephson junction arrays, including full mutual-
inductance effects, as they are cooled below the transition temperature in a
magnetic field. We show numerical simulations of the array magnetization as a
function of position, as detected by a scanning SQUID which is placed at a
fixed height above the array. The calculated magnetization images show striking
agreement with the experimental images obtained by A. Nielsen et al. The
average array magnetization is found to be paramagnetic for many values of the
applied field, confirming that paramagnetism can arise from magnetic screening
in multiply-connected superconductors without the presence of d-wave
superconductivity.Comment: REVTeX 3.1, 5 pages, 5 figure
LA SCUOLA OFFICINA MECCANICA PRESSO IL VILLAGGIO MONTE DEGLI ULIVI A RIESI. RICOSTRUZIONE DI UN PROCESSO TRA ANALISI COMPOSITIVE E GRAFICO-GEOMETRICHE
Il presente contributo trae origine da una pi\uf9 ampia ricerca che ha consentito di approfondire
la comprensione dei principi progettuali e geometrico-compositivi dell\u2019opera in oggetto; avvalendosi
anche di un rilievo scientifico integrato che, attraverso nuove tecniche digitali applicate,
ha permesso di condurre una specifica analisi grafico-geometrica sull\u2019impianto
architettonico1.
L\u2019edificio della scuola officina meccanica, inserito in un pi\uf9 ampio e articolato complesso edilizio2,
\ue8 composto da una singolare configurazione in pianta ai diversi livelli, oggi non pi\uf9
chiaramente leggibile a causa dei numerosi interventi di trasformazione subiti. I disegni di restituzione
grafica, realizzati sulla base dei rilievi architettonici, costituiscono un imprescindibile
documento di consultazione che documenta l\u2019attuale distribuzione dei locali che hanno alterato
l\u2019idea progettuale. Con l\u2019intento di acquisire nuovi elementi di conoscenza propedeutici a futuri
interventi di restauro conservativo e a una pi\uf9 consapevole fruizione del bene, lo studio descrive
ed esamina il processo progettuale dell\u2019opera, ricercando i principi ordinatori, compositivi e
geometrici che ne hanno determinato la particolare struttura.
Il testo \ue8 articolato in due parti: la prima sintetizza le questioni generali del progetto, dalla
ideazione alla realizzazione del Villaggio Monte degli Ulivi e dell\u2019edificio della ex scuola officina
meccanica; la seconda, sulla scorta dei risultati di uno studio sulle funzioni grafiche digitali
applicate alla geometria, indaga la natura geometrica dei profili conici che regolano il progetto
e la realizzazione dell\u2019edificio.This contribution originates from a wider research which allowed to analyse in depth both the design and geometric-compositional principles of the Scuola Officina Meccanica's building - located within the wide and structured building complex in Villaggio \u201cMonte degli Ulivi\u201d. A scientific integrated survey was also used that, thanks to newly-applied digital techniques, allowed to carry out a specific graphic-geometric analysis of the architectural layout. The study is developed in two parts. The first summarizes the general matters of the project, from the design to the realisation of both Villaggio \u201cMonte degli Ulivi\u201d and the building of the former Scuola Officina Meccanica. The second part, on the basis of the results from digital graphic functions applied to the geometry, investigates the geometric nature of the conic profiles regulating both the project and the realisation of the building
A 22-Week-Old Fetus with Nager Syndrome and Congenital Diaphragmatic Hernia due to a Novel SF3B4 Mutation.
Nager syndrome, or acrofacial dysostosis type 1 (AFD1), is a rare multiple malformation syndrome characterized by hypoplasia of first and second branchial arches derivatives and appendicular anomalies with variable involvement of the radial/axial ray. In 2012, AFD1 has been associated with dominant mutations in SF3B4. We report a 22-week-old fetus with AFD1 associated with diaphragmatic hernia due to a previously unreported SF3B4 mutation (c.35-2A>G). Defective diaphragmatic development is a rare manifestation in AFD1 as it is described in only 2 previous cases, with molecular confirmation in 1 of them. Our molecular finding adds a novel pathogenic splicing variant to the SF3B4 mutational spectrum and contributes to defining its prenatal/fetal phenotype
Integration by parts formulas and Lie's symmetries of SDEs
A strong quasi-invariance principle and a finite-dimensional integration by
parts formula as in the Bismut approach to Malliavin calculus are obtained
through a suitable application of Lie's symmetry theory to autonomous
stochastic differential equations. The main stochastic, geometrical and
analytical aspects of the theory are discussed and applications to some
Brownian motion driven stochastic models are provided
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