Nanoscale hydrodynamics near solids

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in The Journal of Chemical Physics 148 (2018): 064107, and may be found at https://aip.scitation.org/doi/10.1063/1.5010401Density Functional Theory (DFT) is a successful and well-established theory for the study of the structure of simple and complex fluids at equilibrium. The theory has been generalized to dynamical situations when the underlying dynamics is diffusive as in, for example, colloidal systems. However, there is no such a clear foundation for Dynamic DFT (DDFT) for the case of simple fluids in contact with solid walls. In this work, we derive DDFT for simple fluids by including not only the mass density field but also the momentum density field of the fluid. The standard projection operator method based on the Kawasaki-Gunton operator is used for deriving the equations for the average value of these fields. The solid is described as featureless under the assumption that all the internal degrees of freedom of the solid relax much faster than those of the fluid (solid elasticity is irrelevant). The fluid moves according to a set of non-local hydrodynamic equations that include explicitly the forces due to the solid. These forces are of two types, reversible forces emerging from the free energy density functional, and accounting for impenetrability of the solid, and irreversible forces that involve the velocity of both the fluid and the solid. These forces are localized in the vicinity of the solid surface. The resulting hydrodynamic equations should allow one to study dynamical regimes of simple fluids in contact with solid objects in isothermal situationsThis research is supported by the Ministerio de Economía y Competitividad of Spain (MINECO) under Grant Nos. FIS2013-47350-C5-1-R and FIS2013-47350-C5-3-

Fluctuating hydrodynamic modelling of fluids at the nanoscale

A good representation of mesoscopic fluids is required to combine with molecular simulations at larger length and time scales (De Fabritiis {\it et. al}, Phys. Rev. Lett. 97, 134501 (2006)). However, accurate computational models of the hydrodynamics of nanoscale molecular assemblies are lacking, at least in part because of the stochastic character of the underlying fluctuating hydrodynamic equations. Here we derive a finite volume discretization of the compressible isothermal fluctuating hydrodynamic equations over a regular grid in the Eulerian reference system. We apply it to fluids such as argon at arbitrary densities and water under ambient conditions. To that end, molecular dynamics simulations are used to derive the required fluid properties. The equilibrium state of the model is shown to be thermodynamically consistent and correctly reproduces linear hydrodynamics including relaxation of sound and shear modes. We also consider non-equilibrium states involving diffusion and convection in cavities with no-slip boundary conditions

A new crested pterosaur from the early cretaceous of Spain: the first European tapejarid (Pterodactyloidea: Azhdarchoidea)

Background: The Tapejaridae is a group of unusual toothless pterosaurs characterized by bizarre cranial crests. From a paleoecological point of view, frugivorous feeding habits have often been suggested for one of its included clades, the Tapejarinae. So far, the presence of these intriguing flying reptiles has been unambiguously documented from Early Cretaceous sites in China and Brazil, where pterosaur fossils are less rare and fragmentary than in similarly-aged European strata. Methodology/Principal Findings: Europejara olcadesorum gen. et sp. nov. is diagnosed by a unique combination of characters including an unusual caudally recurved dentary crest. It represents the oldest known member of Tapejaridae and the oldest known toothless pterosaur. The new taxon documents the earliest stage of the acquisition of this anatomical feature during the evolutionary history of the Pterodactyloidea. This innovation may have been linked to the development of new feeding strategies. Conclusion/Significance: The discovery of Europejara in the Barremian of the Iberian Peninsula reveals an earlier and broader global distribution of tapejarids, suggesting a Eurasian origin of this group. It adds to the poorly known pterosaur fauna of the Las Hoyas locality and contributes to a better understanding of the paleoecology of this Konservat-Lagerstätte. Finally, the significance of a probable contribution of tapejarine tapejarids to the early angiosperm dispersal is discussedAWAK acknowledges the Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ nos. E-26/102.779/2008 and E-26/111.273/2010) and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq no. 307276/2009-0) for supporting research on pterosaurs, including the examination of the Las Hoyas specimen. This study was supported by the Project CGL2009-11838BTE of the Spanish Ministerio de Ciencia e Innovación and the Junta de Castilla-La Manch

Dinosaurios del Cretácico inferior de Galve (Teruel, España)

The aim of this paper is to complete the study of the Dinosaur fauna of the syncline of Galve (Teruel, Spain). Most of the outcrops are Early Barremian in age. Nevertheless, the outcrop called Las Zabacheras could be Hauterivian and El Pelejón Hauterivian-Early Barremian in age. Theropod Dinosaurs are poorly represented. Three vertebral centra are described. They are identified as Theropoda indet. The several outcrops of Galve have yielded four forms of Sauropods. Three of them (cf. Astrodon sp., Camarasauridae indet., form A, Camarasauridae indet., form B) have been identified based on isolated teeth. The Sauropod from Las Zabacheras (Lapparent, 1960; Sanz, 1982) has been proposed as a new taxon, Aragosaurus ischiaticus n. gen. et n. sp. The material which the new taxon is based on are the bones studied by Lapparent (Museo de la Diputación de Teruel) and new ones: caudal vertebrae, chevrones, seapula, ilium, femur and autopodial material. After a research on evolutive polarity of some traits within the Sauropoda, the apomorphic character-states which define the new taxon are as follows: First caudal vertebrae with a great transversal development of the neuroapophysis (club-like), seapular blade terminally expansioned, with an intermediate development (for example between Cetiosaurs and Brachiosaurus or Rebbachisaurus). Great dorso-ventral development (acromio-glenoideus) of the anterior seapular zone (ratio miminal width of the seapular blade/maximal acromio-glenoideus height of 0.27). lliac process of ischium well developed. Pubic process of ischium with great dorso-ventral development (ratio antero-posterior length of this process/lenght of ischiadic contact with pubis, 0.63). Ischiadic process of ischium with a conspicuous final expansion. Lenght ratio humerus/femur 0.82. Lateral bulge just distal to the femoral greater trochanter. Medial condyle of femur relatively developed (ratio maximal antero-posterior diameter of medial condyle/maximal transversal distal femoral width of 0.77). The Aragosaurus taxonomic status is proposed within the family Camarasauridae (sensu Steel, 1970). The Ornithopoda described in this paper mainly belong to the family Hypsilophodontidae, except an isolated tooth identified as Ornithopoda indet. A proximal fragment of a left femur is identified as cf. Valdosaurus sp. Hypsilopbodon foxii has been identified based on a left femur and an ilium.El objetivo principal del presente trabajo ha sido completar el estudio de la fauna de dinosaurios del sinclinal de Galve, de edad mayoritariamente barremiense inferior, aunque el yacimiento de Las Zabacheras puede tener una edad Hauteriviense y el Pelejón Hauteriviense-Barremiense inferior. Los Terópodos están pobremente representados, describiéndose tres centros vertebrales que son identificados como Theropoda indet. Cuatro formas diferentes de Saurópodos han sido identificadas en los diferentes yacimientos de Galve. Tres de ellas (cf. Astrodon sp.; Camarasauridae indet., forma A; Camarasauridae indet., forma B) tan sólo mediante piezas dentarias aisladas. El Saurópodo de Las Zabacheras (Lapparent, 1960; Sanz, 1982) ha sido propuesto como un nuevo taxon, Aragosaurus ischiaticus n. gen. et n. sp. Dicho material consta de diversos restos apendiculares y pélvicos estudiados por Lapparent y depositados en el Museo de la Diputación de Teruel y nuevos elementos consistentes en diversas vértebras caudales, chevrones, escápula, isquion, fémur y restos autopodiales. Las apomorfias más relevantes que definen al nuevo taxon son su relación estilopodial (longitud húmero/fémur) de 0,82, el gran desarrollo relativo dorso-ventral del contorno de contacto con el pubis del proceso pubiano del isquion y la aparición de neuroapáfisis «mazudas» en las primeras vértebras caudales. El enclave taxonómico de Aragosaurus se propone dentro de la familia Camarasauridae (sensu Steel, 1970). Los Ornitópodos descritos en este trabajo pertenecen a la familia Hypsilophodontidae, excepto una pieza dentaria aislada identificada como Ornithopoda indet. Un fragmento proximal de un fémur izquierdo es identificado como cf. Valdosaurus sp. La especie Hypsilophodon foxii ha sido identificada en base a un fémur izquierdo y un íleon

Arcosaurios (Crocodilia, Dinosauria) del Cretácico superior de la Conca de Tremp (Lleida, España)

The study of a great part of the material found during the excavation work carried out by a team of the «Institut de Paleontología de Sabadell» and other paleontologists of the universities of Madrid and Bellaterra, in the basin of Tremp (Maastrichtiense) in 1984 and 1985 has made possible the recognition of: 1.º A large sized Crocodilian, attributable to an adult animal of the Alligatoridae family, comparable to Crocodilus affluvelensis. 2.° Dinosaur remains atributed to three difIerent families: Atlantosauridae (represented by a large sized Sauropod, probably Hypselosaurus); Iguanodontidae (afI. Rhabdodon, medium sized Omithopod); and Hadrosauridae (Ortbomerus, small sized). 3.° Dinosaur's footprints, not very well preserved, medium and large sized, attributable to biped Omithopod. The fauna remains were always found unconnected, scattered all over large areas and with no signs of depredation. The sort of materials found reveal a certain transport which caused a selective action over the remains. Later, the efIects of the orogenic processes suffered by this area in the Tertiary period would combine with this transport.El estudio de gran parte del material hallado en los trabajos de excavación realizados por un equipo del «Institut de Paleontología de Sabadell» y otros paleontólogos de las Universidades de Madrid y Bellaterra, en la cuenca de Tremp (Maastrichtiense), durante los años 1984 y 1985, ha permitido reconocer: 1.º Un crocodílido de gran talla, atribuible a un animal adulto de la familia Alligatoridae, comparable a Crocodilus affluvelensis. 2.° Restos de dinosaurios que se han atribuido a tres familias: Atlantosauridae (representada por un saurópodo de gran talla, probablemente Hypselosaurus); Iguanodontidae (afI. Rhabdodon, ornitópodo de talla media), y Hadrosauridae (Ortbomerus, de talla pequeña). 3.° Icnitas de dinosaurios, bastante mal conservadas, de tamaño medio y grande, atribuibles a omitópodos bípedos. Los restos faunísticos han sido hallados siempre inconexos, esparcidos en extensas superficies y sin señales de depredación. El tipo de material hallado indica, en principio, un cierto transporte, el cual ejerció una acción selectiva sobre los restos. Posteriormente, a este transporte se unirían los efectos de los procesos orogénicos que afectaron la zona durante el Terciario

Does ohmic heating influence the flow field in thin-layer electrodeposition?

In thin-layer electrodeposition the dissipated electrical energy leads to a substantial heating of the ion solution. We measured the resulting temperature field by means of an infrared camera. The properties of the temperature field correspond closely with the development of the concentration field. In particular we find, that the thermal gradients at the electrodes act like a weak additional driving force to the convection rolls driven by concentration gradients.Comment: minor changes: correct estimation of concentration at the anode, added Journal-re

A New Crocodylian from the Late Maastrichtian of Spain: Implications for the Initial Radiation of Crocodyloids

The earliest crocodylians are known primarily from the Late Cretaceous of North America and Europe. The representatives of Gavialoidea and Alligatoroidea are known in the Late Cretaceous of both continents, yet the biogeographic origins of Crocodyloidea are poorly understood. Up to now, only one representative of this clade has been known from the Late Cretaceous, the basal crocodyloid Prodiplocynodon from the Maastrichtian of North America.The fossil studied is a skull collected from sandstones in the lower part of the Tremp Formation, in Chron C30n, dated at -67.6 to 65.5 Ma (late Maastrichtian), in Arén (Huesca, Spain). It is located in a continuous section that contains the K/P boundary, in which the dinosaur faunas closest to the K/P boundary in Europe have been described, including Arenysaurus ardevoli and Blasisaurus canudoi. Phylogenetic analysis places the new taxon, Arenysuchus gascabadiolorum, at the base of Crocodyloidea.The new taxon is the oldest crocodyloid representative in Eurasia. Crocodyloidea had previously only been known from the Palaeogene onwards in this part of Laurasia. Phylogenetically, Arenysuchus gascabadiolorum is situated at the base of the first radiation of crocodyloids that occurred in the late Maastrichtian, shedding light on this part of the cladogram. The presence of basal crocodyloids at the end of the Cretaceous both in North America and Europe provides new evidence of the faunal exchange via the Thulean Land Bridge during the Maastrichtian