3,755 research outputs found
Nonlinear aeroelastic modeling via conformal mapping and vortex method for a flat-plate airfoil in arbitrary motion
A nonlinear aerodynamic modeling based on conformal mapping is presented to obtain semi-analytical formulas for the unsteady aerodynamic force and pitching moment on a flat-plate airfoil in arbitrary motion. The aerodynamic model accounts for large amplitudes and non-planar wake and is used to study the aeroelastic behavior of a flat-plate airfoil elastically connected to a support. The fluid is assumed to be inviscid and incompressible, while the flow is assumed to be attached, planar, and potential. Within these hypotheses, conformal mapping and a complex-potential representation of unsteady aerodynamics are used to simplify the theoretical formulation. The vorticity shed at the trailing edge is discretized in desingularized point vortices in order to allow free-wake dynamics. The unsteady aerodynamic model is validated with classical linearized formulations based on the assumption of small disturbances, and with experimental data and theoretical predictions for a large-amplitude pitch-up, hold, pitch-down maneuver. The aeroelastic model is then used to simulate the response of a flat-plate airfoil to sudden starts and body-vortex interactions. Numerical results show that the proposed approach can be an effective tool to model the aeroelastic behavior of an arbitrarily-moving wing section in a time-dependent potential stream of incompressible fluid
Hettangian and Sinemurian (Lower Jurassic) biostratigraphy of Argentina
On the northern bank of the Rio Atuel, Mendeza province, Argentina, the marine fossilfferous Mesozoic is now known to begin with Hettangian-lower Sinemurian strata. Traditionally, the marine Jurassic sequence in the area was believed to start with upper Sinemurian levels. Representatives of the genera Psiloceras Hyatt, Caloceras Hyatt, Alsatites Haug, Waehneroceras Hyatt, Schlotheimia Bayle, Sulciferites Spath, Badouxia Guex and Taylor, Vermiceras Hyatt, Coroniceras Hyatt, Agassiceras Hyatt, Euagassiceras Spath, and Arnioceras Hyatt thus indicate the presence of beds equivalent to the Planorbis, Liasieus, Angulata, Bucklandi, Semicostatum, and Turneri zones of the standard international chronostratigraphic scale. Hence, in Argentina, the marine Hettangian, Sinemurian, and lowermost Pliensbachian have been proved only in the neighborhood of the Rio Atuel region, where marine Triassic could also be represented. Elsewhere in Argentina, the oldest Jurassic ammonite-bearing levels usually belong to the upper lower or the upper Pliensbachian. Regionally, these findings imply a substantial modification to previous paleogeographic reconstructions for the Early Jurassic of South America.En la margen norte del rio Atuel, Mendoza, Argentina, la sucesi6n fosilifera marina del Mesozoieo comienza con niveles del Hettangiano y Sinemuriano inferior. Tradicionalmente se habia considerado queen la regi6n el Jur~sico marino comenzaba con el Sinemuriano superior. Representantes de los g~neros Psiloceras Hyatt, Caloceras Hyatt, Alsatites Haug, Waehneroceras Hyatt, Schlotheimia Bayle, Sulciferites Spath, Badouxia Guex y Taylor, Vermiceras Hyatt, Coroniceras Hyatt, Agassiceras Hyatt, Euagassieeras Spath y Arnioceras Hyatt, indican la presencia de estratos equivalentes alas zonas de Planorhis, Liasieus, Angulata, Bucklandi, Semicostatum y Turneri de la Escala Cronoestratigrafica Internacional. Asi en Argentina el Hettangiano, Sinemuriano, y Pliensbachiano basal marinos solamente han sido comprobados en proximidades de la regi6n del rio Atuel, donde tambi~n podrian hallarse representados niveles de Tri~sico marino. En el resto de Argentina los niveles m~s antiguos portadores de amonites del Jur~isico corresponden generalmente al Pliensbachiano inferior alto o Pliensbachiano superior. Desde el punto de vista regional estos hallazgos determinan una modificaci6n substancial en la paleogeografia del Jur~sico temprano de America del Sur.Facultad de Ciencias Naturales y Muse
Which benefit from subsequent chemotherapy lines beyond the second for women with metastatic breast cancer? Evidence from a single-center retrospective analysis of survivorship
n/
Benefit of continuing trastuzumab beyond progression in her2-positive metastatic breast cancer (mbc) is independent of the chemotherapy partner: message from a single-centre retrospective study
n/
Study of high-pT charged particle suppression in PbPb compared to pp collisions at sqrt(sNN)=2.76 TeV.
The transverse momentum spectra of charged particles have been measured in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV by the CMS experiment at the LHC. In the transverse momentum range pt = 5-10 GeV/c, the charged particle yield in the most central PbPb collisions is suppressed by up to a factor of 5 compared to the pp yield scaled by the number of incoherent nucleon-nucleon collisions. At higher pt, this suppression is significantly reduced, approaching roughly a factor of 2 for particles with pt in the range pt=40-100 GeV/c
Effect of an Anhydride Excess on the Curing Kinetics and Dynamic Mechanical Properties of Synthetic and Biogenic Epoxy Resins
This work analyzes the effect of the anhydride excess on the nonisothermal curing kinetics and on the final properties of synthetic and biobased epoxy resins. Diglycidyl ether of bisphenol A (DGEBA) and epoxidized soybean oil (ESO) were crosslinked using methyltetrahydrophthalic anhydride (MTHPA) as a curing agent and 1-methylimidazole (1MI) as an initiator. It was shown that the ESO/MTHPA/1MI system reacts slower than the DGEBA/MTHPA/1MI system, giving place to a more significant evaporation of the curing agent during the reaction. As a result, an excess of anhydride improves the final thermal properties of the ESO/MTHPA/1MI network, contrary to the behavior observed for DGEBA/MTHPA/1MI. The knowledge of the kinetics of the curing process and the optimal amount of the curing agent for each system is of critical importance for a more efficient processing of these materials.Fil: Altuna, Facundo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Riccardi, Carmen Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Marin Quintero, Diana Catalina. Royal Institute of Technology; Suecia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ruseckaite, Roxana Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin
Marine Mesozoic Biostratigraphy of the Neuquén Basin
The marine Mesozoic of the Neuquen Basin in central west Argentina is characterized by ammonites and other invertebrates, especially bivalves, brachiopodes and calcareous microfossils. On that basis, Upper Triassic to Oxfordian, and Tithonian to Barremian have been divided in 39 and 18 ammonite assemblage / zones respectively, corresponding to 15 and 4 for bivalves, 15 and 2 for bra- chiopods and 11 and 9 for microfossils.El Mesozoico marino de la Cuenca de Neuquén, en el centro oeste argentino, se caracteriza por ammonites y otros invertebrados, tales como bivalvos, braquiópodos y microfósiles calcáreos. Sobre esta base, las unidades del Triásico Superior - Oxfordiano y la del Tithoniano - Barremiano, se han dividido en 39 y 18 zonas de grupos de ammonites, los que a su vez, corresponden respectivamente a 15 y 4 zonas de bivalvos, 15 y 2 de braquiópodos, y 11 y 9 zonas de microfósiles.Facultad de Ciencias Naturales y Muse
EFEITO DO JEJUM PÓS-ECLOSÃO SOBRE PINTOS DE CORTE PROVENIENTES DE OVOS LEVES E PESADOS
Este estudo analisou o efeito do jejum pós-eclosão sobre o peso corporal e pesos do fígado, coração e saco de vitelo de pintos provenientes de ovos leves de matrizes jovens (29 semanas) e de ovos pesados de matrizes velhas (60 semanas). Foi analisado o efeito de três regimes alimentares (alimentação com água e ração, jejum de água e ração e jejum de ração), da duração do jejum (24, 48 e 72 horas), e de dois pesos de ovos (leves ou pesados), e as suas interações. O jejum afetou os pesos corporal e dos órgãos. Pintos de ovos pesados perderam mais peso e absorveram mais o saco de vitelo que os pintos de ovos leves. O efeito do jejum sobre os pesos corporal e do fígado ocorreu com 24 horas, e sobre o peso do coração com 72 horas.
PALAVRAS-CHAVES: Idade da matriz, jejum, órgãos, peso corporal.
In Vitro Blood Compatibility of Novel Hydrophilic Chitosan Films for Vessel Regeneration and Repair
- …