Search results for "Dynamic"
showing 10 items of 12329 documents
New Insights into Segmental Packing, Chain Dynamics and Thermomechanical Performance of Aliphatic Polyurea Composites: Comparison between Silica Oxid…
2021
Polyurea (PU) is intrinsically reinforced by its microphase-separated morphology, giving its excellent mechanical properties. In this study, it is shown how a high-index PU formulation applies easy diffusion of hard segments into the soft phase of the PU matrix and tune its chain mobility. Moreover, the interaction of micro (>100 nm), nano (<100 nm) fillers with the microdomains and their thermomechanical properties are unraveled. Herein, nanosilica oxide (NS) and micro titanium (III) oxide (Ti2O3) are incorporated at low loadings into a solvent-free two-component aliphatic PU via insitu polymerization. While NS achieves an interfacial interaction with urea groups and forms a tight ha…
Hölder regularity for stochastic processes with bounded and measurable increments
2022
We obtain an asymptotic Hölder estimate for expectations of a quite general class of discrete stochastic processes. Such expectations can also be described as solutions to a dynamic programming principle or as solutions to discretized PDEs. The result, which is also generalized to functions satisfying Pucci-type inequalities for discrete extremal operators, is a counterpart to the Krylov-Safonov regularity result in PDEs. However, the discrete step size $\varepsilon$ has some crucial effects compared to the PDE setting. The proof combines analytic and probabilistic arguments.
To correct or to cooperate : Mediational processes and L2 development
2018
The present article argues for a conceptual distinction between corrective feedback and mediation that emphasizes the status of the latter not as an instructional practice but as a defining feature of human psychology (Vygotsky, 1987) that has direct implications for how instruction might be approached. Specifically, Sociocultural Theory (SCT) posits that humans are always and everywhere mediated, as individuals draw upon meanings and ways of thinking they have already internalized as well as those that are available in their immediate environment to regulate their actions. With regard to second language (L2) education, rather than exclusively focusing on learner independent performance or…
From conceptualization to constructions in Finnish as an L2 : a case study
2017
AbstractThis study traces the individual learning trajectories of an adult beginner L2 Finnish learner in expressing the extralinguistic concept of evaluation from a dynamic usage-based perspective. Our results provide support for the view of learner language as a dynamic system in which patterns wax and wane and in which a change in one component has the potential to affect the whole system. In the early stages of learning there was a strong preference to use lexical verbs first, and then adjectives. The study also shows that variability plays a role. Finally, the study confirms that the learning of L2 constructions is in some cases item based. However, another highly frequent and superfic…
Developing a metatheoretical framework for second language development : a cultural-historical theory and dynamic systems theory perspective
2017
The main aim of this article-based dissertation is to construct and articulate a dialectical metatheoretical architecture for the study of second language development termed Purposive-Historical Systems Theory (PHiST) invoking, inter alia, the axiomatic imperatives of dynamic systems theory (DST), Vygotskian cultural-historical theory (CHT), and Pepperian root metaphor theory (RMT). Specifically, it primarily purports, first, to demonstrate the tenability of a dialectical synthesis of DST and CHT; second, to philosophize on the fundamental contours of PHiST; third, to apply a novel metatheoretical perspective, as a quintessential example, to reconceptualizing the seminal construct of the Zo…
Dancing with Alternative Lyrics : Integrating Sociocultural, Dialogical, Distributed and Dynamical Conceptualization of Language and its Development …
2016
This paper sets out to chart underlying assumptions and fundamental axioms of an integrative research edifice for studying language and how it is developed over time as a human- and culture-centered and multifaceted phenomenon. Specifically, invoking Vygotskian sociocultural theory, the Bakhtin circle dialogism, distributed language and cognition and dynamic systems theory, it is argued that language is a purposive, multifaceted, complex, dialogical, and dynamic system that emerges distributively across the interpenetrated web of human somatic and brain activities, socio-cultural umwelt, sociohistorically-fashioned artifacts and realized affordances simultaneously and over time. Suggestions…
The dynamics of foreign versus second language development in Finnish writing
2014
Deze studie vanuit een dynamisch perspectief onderzoekt de ontwikkeling van acht beginnende leerders Fins als vreemde (VT; Nederland; focus: grammatica) en tweede (T2; Finland; focus: communicatie) taal. De studie onderzoekt variabelen die syntactische en morfologische complexiteit en accuraatheid uitdrukken in geschreven data en bekijkt verschillen in uitkomsten tussen de groepen en verschillen in ontwikkelingspatronen en interacties door de tijd (9 maanden) tussen variabelen (één hoofdpersoon per groep). De groepstudie toont overeenkomsten in syntactische en morfologische complexiteit door de tijd heen maar verschillen in het gebruik van naamvallen en van enkele daaraan gerelateerde varia…
On elliptic equations involving the 1-Laplacian operator
2018
El objetivo de esta tesis doctoral es dar a conocer los resultados obtenidos sobre existencia, unicidad y regularidad de las soluciones de diferentes ecuaciones elípticas regidas por el operador 1-laplaciano. El primer capítulo está dedicado al estudio de la ecuación - div (Du/|Du|) + g(u) |Du| = f(x) en un subconjunto abierto y acotado U de R^N con frontera Lipschitz, con la condición de Dirichlet u=0 en la frontera, tomando una función f positiva y siendo g una función real, continua y positiva. Por un lado, obtenemos soluciones no acotadas cuando el dato f pertenece al espacio de Marcinkiewicz L^{N,\infty}(U), por lo que debemos introducir la definición apropiada para este tipo de soluci…
Three-dimensional core-collapse supernovae with complex magnetic structures: I. Explosion dynamics
2021
Magnetic fields can play a major role in the dynamics of outstanding explosions associated to violent events such as GRBs and hypernovae, since they provide a natural mechanism to harness the rotational energy of the central proto-neutron star and power relativistic jets through the stellar progenitor. As the structure of such fields is quite uncertain, most numerical models of MHD-driven core-collapse supernovae consider an aligned dipole as initial magnetic field, while the field's morphology can actually be much more complex. We present three-dimensional simulations of core-collapse supernovae with more realistic magnetic structures, such as quadrupolar fields and, for the first time, an…
The impact of non-dipolar magnetic fields in core-collapse supernovae
2019
The magnetic field is believed to play an important role in at least some core-collapse supernovae if its magnitude reaches $10^{15}\,\rm{G}$, which is a typical value for a magnetar. In the presence of fast rotation, such a strong magnetic field can drive powerful jet-like explosions if it has the large-scale coherence of a dipole. The topology of the magnetic field is, however, probably much more complex with strong multipolar and small-scale components and the consequences for the explosion are so far unclear. We investigate the effects of the magnetic field topology on the dynamics of core-collapse supernovae and the properties of forming proto-neutron star (PNS) by comparing pre-collap…