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Search Results: 1 - 10 of 6006 matches for " Alfredo Hermenegildo "
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Angélica y el desencadenamiento de la locura: Lope de Rueda y Tirso de Molina
Hermenegildo, Alfredo
Arbor : Ciencia, Pensamiento y Cultura , 2004,
Abstract: La locura, como recurso dramático, aparece en dos obras separadas por unas cuantas décadas: la Mederà, de Lope de Rueda, y La villana de la Sagra, de Tirso de Molina. En la primera, la presencia destructora y conflictiva de unos hermanos gemelos desencadena la locura de unos individuos, los padres de la protagonista, que alteran con sus andanzas la convivencia social del grupo a que pertenecen. La fiesta carnavalesca está también en la base misma de la construcción de los locos. En la obra de Tirso, la locura del galán, de don Luis, es utilizada para detener, con su fondo libresco, el desarrollo previsible de la fábula.…
Figuras reales en el Códice de autos viejos
Alfredo Hermenegildo
Castilla : Estudios de Literatura , 2009,
Allotropic Carbon Nanoforms as Advanced Metal-Free Catalysts or as Supports
Hermenegildo Garcia
Advances in Chemistry , 2014, DOI: 10.1155/2014/906781
Abstract: This perspective paper summarizes the use of three nanostructured carbon allotropes as metal-free catalysts (“carbocatalysts”) or as supports of metal nanoparticles. After an introductory section commenting the interest of developing metal-free catalysts and main features of carbon nanoforms, the main body of this paper is focused on exemplifying the opportunities that carbon nanotubes, graphene, and diamond nanoparticles offer to develop advanced catalysts having active sites based on carbon in the absence of transition metals or as large area supports with special morphology and unique properties. The final section provides my personal view on future developments in this field. 1. Introduction: From Active Carbons to Carbon Allotropes In classical heterogeneous catalysis, active carbons (ACs) have been widely used as supports for noble metal and metal oxides [1–3]. ACs are high surface area materials having carbon as predominant element in their composition that are obtained by pyrolysis of available biomass wastes, upon addition of inorganic reagents to promote the carbonisation process. For instance, one popular active carbon comes from coconut shells adequately powdered, pyrolyzed at 600°C under N2, mixed with phosphoric acid for activation, and then baked at temperatures below 300°C [4, 5]. In other recipes, olive seeds or almond shells are used as AC precursors and other mineral acids or oxidizing chemicals are employed as additives [6–8]. The structure of ACs is poorly defined with domains of amorphous carbon and the presence of condensed polycyclic aromatic compounds forming platelets of nanometric dimensions that are interconnected by bridges that can be CH2 and heteroatoms such as O, NH, and S. In certain regions, ACs have graphitic domains when the platelets are large enough and stacking of the imperfect graphene (G) sheets can take place. Besides oxygen and other elements such as nitrogen or sulphur, metal traces such as iron, zinc, and copper, are very frequently present in the final composition of the material because these transition metals have been introduced as additives in the pyrolysis process and they remain in residual, sometimes not negligible, percentages. Understanding the mechanism in heterogeneous catalysis largely depends on the exhaustive characterization of the solid catalyst and on the knowledge on the architecture of the active sites [9]. In this sense, while ACs are available and affordable materials exhibiting high adsorption capacity, this property being suitable for their use as support, they are too complex and
Adorno, arte e educa??o: negócio da arte como nega??o
Fabiano, Luiz Hermenegildo;
Educa??o & Sociedade , 2003, DOI: 10.1590/S0101-73302003000200010
Abstract: the main investigation in this paper aims at understanding that a work of art in its internal form gets a relative autonomy from the empiric reality of which it becomes a critical reflection. as mediation to the social and historical reality that produced it, art is characterized as a negation of this same reality. this principle of determined negation as an antithesis of society is condensed in a work of art as the problem of its internal form, an element to which theodor w. adorno conferred an epistemological dimension. in this category of knowledge, considered through the aesthetics perspective, the instrumental reason as a brutal praxis of surviving is concretely questioned in its restrictive form of knowledge.
Adorno, arte e educa o: negócio da arte como nega o
Fabiano Luiz Hermenegildo
Educa??o & Sociedade , 2003,
Abstract: O eixo temático desta investiga o trata de compreender que a obra de arte corporifica na sua forma interna uma autonomia relativa com rela o à realidade empírica sobre a qual se torna reflex o crítica. Ao se caracterizar como media o com a realidade social que a produziu, a arte é por isso mesmo a sua nega o. é esse princípio de nega o determinada, em que se condensam na obra de arte as antinomias e os antagonismos como antíteses da sociedade enquanto problema de sua forma interna, o elemento ao qual Theodor W. Adorno atribui dimens o epistemológica. Nessa categoria do conhecimento assim concebida, pela perspectiva estética, a raz o instrumental como práxis brutal da sobrevivência é concretamente questionada na sua forma restritiva de conhecimento.
Existence for the steady problem of a mixture of two power-law fluids
Hermenegildo Borges de Oliveira
Physics , 2012,
Abstract: The steady problem resulting from a mixture of two distinct fluids of power-law type is analyzed in this work. Mathematically, the problem results from the superposition of two power laws, one for a constant power-law index with other for a variable one. For the associated boundary-value problem, we prove the existence of very weak solutions, provided the variable power-law index is bounded from above by the constant one. This result requires the lowest possible assumptions on the variable power-law index and, as a particular case, extends the existence result by Ladyzhenskaya dated from 1969 to the case of a variable exponent and for all zones of the pseudoplastic region. In a distinct result, we extend a classical theorem on the existence of weak solutions to the case of our problem.
The Navier-Stokes problem modified by an absorption term
Hermenegildo Borges de Oliveira
Mathematics , 2009,
Abstract: In this work we consider the Navier-Stokes problem modified by the absorption term $|\textbf{u}|^{\sigma-2}\textbf{u}$, where $\sigma>1$, which is introduced in the momentum equation. % For this new problem, we prove the existence of weak solutions for any dimension $N\geq 2$ and its uniqueness for N=2. % Then we prove that, for zero body forces, the weak solutions extinct in a finite time if $1<\sigma<2$, exponentially decay in time if $\sigma=2$ and decay with a power-time rate if $\sigma>2$. % We prove also that for a general non-zero body forces, the weak solutions exponentially decay in time for any $\sigma>1$. In the special case of a suitable forces field which vanishes at some instant, we prove that the weak solutions extinct at the same instant provided $1<\sigma<2$.
On the existence of weak solutions for steady flows of generalized viscous fluids
Hermenegildo Borges de Oliveira
Mathematics , 2011,
Abstract: In this work we investigate the existence of weak solutions for steady flows of generalized incompressible and homogeneous viscous fluids. The problem is modeled by the steady case of the generalized Navier-Stokes equations, where the exponent $q$ that characterizes the flow depends on the space variable: $q=q(\mathbf{x})$. For the associated boundary-value problem we prove the existence of weak solutions for any variable exponent $q\geq\alpha>\frac{2N}{N+2}$, where $\alpha=\mathrm{ess}\inf q$. This work improves all the known existence results in the sense that the lowest possible bound of $q$ is attained and no other assumption on the regularity of $q$ is required.
A note about existence for a class of viscous fluid problems
Hermenegildo Borges de Oliveira
Mathematics , 2012,
Abstract: In this work the existence of weak solutions for a class of non-Newtonian viscous fluid problems is analyzed. The problem is modeled by the steady case of the generalized Navier-Stokes equations, where the exponent $q$ that characterizes the flow depends on the space variable: $q=q(\mathbf{x})$. For the associated boundary-value problem we show that, in some situations, the log-H\"older continuity condition on $q$ can be dropped and the result of the existence of weak solutions still remain valid for any variable exponent $q\geq\alpha>\frac{2N}{N+2}$, where $\alpha=\mathrm{ess}\inf q$.
Existence of weak solutions for the generalized Navier-Stokes equations with damping
Hermenegildo Borges de Oliveira
Mathematics , 2011,
Abstract: In this work we consider the generalized Navier-Stoke equations with the presence of a damping term in the momentum equation. % The problem studied here derives from the set of equations which govern the isothermal flow of incompressible, homogeneous and non-Newtonian fluids. % For the generalized Navier-Stokes problem with damping, we prove the existence of weak solutions by using regularization techniques, the theory of monotone operators and compactness arguments together with the local decomposition of the pressure and the Lipschitz-truncation method. The existence result proved here holds for any $q>\frac{2N}{N+2}$ and any $\sigma>1$, where $q$ is the exponent of the diffusion term and $\sigma$ is the exponent which characterizes the damping term.
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