1,726,626 research outputs found
The Role of Three-Body Interactions on the Equilibrium and Non-Equilibrium Properties of Fluids from Molecular Simulation
Full text linkThe aim of this work is to use molecular simulation to investigate the role of
three-body interatomic potentials in noble gas systems for two distinct
phenomena: phase equilibria and shear flow. In particular we studied the
vapour-liquid coexisting phase for pure systems (argon, krypton and x enon) and
for an argon-krypton mixture, utilizing the technique called Monte Carlo Gibbs
ensemble. We also studied the dependence of the shear viscosity, pressure and
energy with the strain rate in planar Couette flow, using a non-equilibrium
molecular simulation (NEMD) technique.
The results we present in this work demonstrate that three-body interactions
play an important role in the overall interatomic interactions of noble gases. This
is demonstrated by the good agreement between our simulation results and the
experimental data for both equilibrium and non-equilibrium systems.
The good results for vapour-liquid coexisting phases encourage performing
further computer simulations with realistic potentials. This may improve the
prediction of quantities like critical temperature and density, in particular of
substances for which these properties are difficult to obtain from experiment.
We have demonstrated that use of accurate two- and three-body potentials for
shearing liquid argon and xenon displays significant departure from the
expected strain rate dependencies of the pressure, energy and shear viscosity.
For the first time, the pressure is convincingly observed to vary linearly with an
apparent analytic g&2 dependence, in contrast to the predicted g&3/ 2 dependence
of mode -coupling theory. Our best extrapolation of the zero -shear viscosity for
argon gives excellent agreement (within 1%) with the known experimental data.
To the best of our knowledge, this the first time that such accuracy has been
achieved with NEMD simulations. This encourages performing simulations with
accurate potentials for transport properties
Existence of Bounded Trajectories Via Upper and Lower Solutions
No full textThe paper deals with the boundary value problem (on the whole line) u''-f(u,u')+g(u)=0, u(-∞)=0, u(+∞)=1, where g is a continuous non-negative function with support [0, 1], and f is a continuous function. By means of a new approach, based on a combination of lower and upper-solutions methods and phase-plane techniques, we prove an existence result for the problem when f is superlinear in u'; by a similar technique, we also get a non-existence one. As an application, we investigate the attractivity of the singular point (0,0) in the phase-plane (u, u'). Applications of these results in the field of front-type solutions for reaction diffusion equations can be found in L. Malaguti, C. Marcelli, Math. Nachr. 242 (2002), 148—16
Francesco Filelfo, Corrispondenza. I. Lettere volgari. Edizione critica e commento a cura di Nicoletta Marcelli
No full textNel panorama dell’umanesimo italiano a fianco di numerosi e celebri autori che, sull'esempio di Francesco Petrarca, si dedicarono alla composizione di un epistolario latino, possiamo annoverarne altrettanti per ciò che concerne l’epistolografia in volgare, ma, assai rari sono i casi di umanisti che per la scrittura di lettere si siano cimentati sul doppio registro latino-volgare e, nel caso di Filelfo, con l’aggiunta del greco.
Se all’Epistolario latino e greco, raccolto, rielaborato e concepito con le caratteristiche di una vera e propria opera letteraria destinata alla pubblicazione Filelfo dedicò notevoli cure per molti anni, alle lettere volgari, al contrario, l’autore non riconobbe uno statuto letterario, per cui la loro sorte è stata quella della totale dispersione, al punto che non se ne conosceva neppure il numero complessivo. Grazie a questo lavoro il corpus conta oggi 141 lettere, parte delle quali sconosciute e inedite, in larga misura autografe, indirizzate ad alcune tra le maggiori personalità della politica e della cultura del Quattrocento: fra tutti spiccano i duchi Francesco e Galeazzo Maria Sforza, Lorenzo il Magnifico e il cancelliere sforzesco Cicco Simonetta. Le lettere toccano molti aspetti della storia e della cultura del secolo XV, dalla politica, alla diplomazia, dalle humanae litterae, alla biografia di Filelfo stesso. Nella loro varietà rispecchiano a pieno la poliedrica personalità dell’autore, il cui profilo intellettuale appare mirabilmente definito nell'ampio percorso della sua Corrispondenza, che si completa con gli altri corpora previsti dal progetto (epistole greche, latine, estravaganti), entro il quale questo primo volume si inscrive
Malpighii, Marcelli; Fracassati, Caroli
No full textMalpighii, Marcelli; Fracassati, Caroli. Epistolæ anatomicæ virorum clarissimorum Marcelli Malpighii et Caroli Fracassati. Quarum contenta pagina versa exhibet, 1669
Full text
Subjects: Human anatomy--Early works to 1800
Language: Latinhttps://digitalcommons.rockefeller.edu/rare-books/1118/thumbnail.jp
Circeaster marcelli Koehler 1909
No full textCirceaster marcelli Koehler, 1909 Circeaster marcelli Koehler, 1909: 84, pl. IV, figs 1, 2, pl. VI, fig. 1. — Clark 1993: 251. MATERIAL EXAMINED. — No specimens available for examination. DISTRIBUTION. — Recorded from 7°23'N, 75°44'E in the Indian Ocean. 1926 m (1053 fms). DIAGNOSIS. — R/r = 2.67. Arm plates significantly larger than disk plates.Transition abrupt between abactinal disk and arm plates. Abactinal granules absent. Superomarginals not abutting at midline, arm plates continuous to terminal. Interradial arcs linear.Spinelets and granules with spiny tips cover superomarginal, inferomarginal plates, actinal surface. Seven to eight thick, blunt furrow spines. Prominent paddle-like toothed pedicellariae, separated from furrow spines. Granules identical to actinal surface present on remainder of adambulacral plate. APOMORPHY LIST. — Nodes 14 to Circeaster marcelli: 1.4, abactinal accessories absent; 1.6, no size, accessories absent. DESCRIPTION See Koehler (1909; translation in English of the description is available from the author).Published as part of Mah, Christopher L., 2006, Phylogeny and biogeography of the deep-sea goniasterid Circeaster (Echinodermata, Asteroidea, Goniasteridae) including descriptions of six new species, pp. 917-954 in Zoosystema 28 (4) on page 935, DOI: 10.5281/zenodo.452546
Estudos taxonômicos em Parmotrema s.l. (Parmeliaceae, Ascomycota liquenizados) com ácido salazínico
Full text linkAs espécies do gênero Parmotrema s.l. com ácido salazínico são revisadas, com base
especialmente nos tipos das espécies aceitas e de seus sinônimos. São fornecidas chave e
descrições para 61 espécies, incluindo sinonímia, química, distribuição e discussão das
afinidades taxonômicas de cada táxon.
Foi utilizada metodologia clássica em Liquenologia, contando com uso de microscópio óptico e
estereoscópico, bem como ferramentas químicas para identificação das substâncias de
importância taxonômica, tais como testes de coloração, lâmpada UV, cromatografia em camada
delgada (TLC) e, para várias espécies, cromatografia líquida de alta eficiência (CLAE).
Duas espécies novas são descritas: Parmotrema austromaculatum e P. bifidum. Uma nova
combinação dentro de Parmelinella foi proposta, P. afrocetrata (Elix, Fischer & Killmann)
Marcelli & Spielmann, e 14 novas combinações em Parmotrema: P. acanthifolium (Pers.)
Spielmann & Marcelli, P. concors (Kremp.) Spielmann & Marcelli, P. foliolosum (C.W. Dodge)
Spielmann & Marcelli, P. granularis (Asahina) Spielmann & Marcelli, P. herrei (Zahlbr.)
Spielmann & Marcelli, P. livido-tesselatum (Hue) Spielmann & Marcelli, P. magnum (Lynge)
Spielmann & Marcelli, P. maximum (Hue) Spielmann & Marcelli, P. nudum (Hue) Spielmann &
Marcelli, P. petropoliense ( Zahlbr.) Spielmann & Marcelli, P. radiatum (Lynge) Spielmann &
Marcelli, P. reterimulosum (Zahlbr.) Spielmann & Marcelli, P. sieberi (C.W. Dodge) Spielmann
& Marcelli e P. warmingii (Vainio) Spielmann & Marcelli. Doze táxons permanecem sem status
definido e estão dentro dos Nomina inquirenda.species as well as his synonyms. A key and descriptions for the 61 species are given, and the
synonymy, chemistry, distribution and taxonomic affinities of each species are discussed.
Classical methods in Lichenology were employed, using stereomicroscope and optical
microscopy for the observations, and spot tests, TLC and HPLC for the chemical analysis.
Two new species are described: Parmotrema austromaculatum e P. bifidum. One new
combination in Parmelinella was made, P. afrocetrata (Elix, Fischer & Killmann) Marcelli &
Spielmann, and 14 new combinations in Parmotrema: P. acanthifolium (Pers.) Spielmann &
Marcelli, P. concors (Kremp.) Spielmann & Marcelli, P. foliolosum (C.W. Dodge) Spielmann &
Marcelli, P. granularis (Asahina) Spielmann & Marcelli, P. herrei (Zahlbr.) Spielmann &
Marcelli, P. livido-tesselatum (Hue) Spielmann & Marcelli, P. magnum (Lynge) Spielmann &
Marcelli, P. maximum (Hue) Spielmann & Marcelli, P. nudum (Hue) Spielmann & Marcelli, P.
petropoliense ( Zahlbr.) Spielmann & Marcelli, P. radiatum (Lynge) Spielmann & Marcelli, P.
reterimulosum (Zahlbr.) Spielmann & Marcelli, P. sieberi (C.W. Dodge) Spielmann & Marcelli
and P. angustatum (Vainio) Spielmann & Marcelli. Twelve taxa remain without definite status
and are included in the Nomina inquirenda
On the relationship between two-body and three-body interactions from nonequilibrium molecular dynamics simulation
No full textNonequilibrium molecular dynamics (NEMD) simulations are performed for argon at different strain rates using accurate two-body and three-body intermolecular potentials. The contributions of two- and three-body interactions to the configurational energy of argon at different strain rates are reported. The NEMD data indicate that there is the same simple relationship between two- and three-body interactions as reported previously Marcelli and Sadus, J. Chem. Phys. 112, 6382 (2000) from equilibrium Monte Carlo simulations. The relationship is largely independent of strain rate. NEMD calculations using this relationship for shear viscosity at different strain rates indicate good agreement with full two-body+three-body calculations. This means that the effect of three-body interactions on transport properties might be achieved in a conventional two-body NEMD simulation without incurring the computational penalty of three-body calculations
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