Solitary and compact-like shear waves in the bulk of solids

We show that a model proposed by Rubin, Rosenau, and Gottlieb [J. Appl. Phys. 77 (1995) 4054], for dispersion caused by an inherent material characteristic length, belongs to the class of simple materials. Therefore, it is possible to generalize the idea of Rubin, Rosenau, and Gottlieb to include a wide range of material models, from nonlinear elasticity to turbulence. Using this insight, we are able to fine-tune nonlinear and dispersive effects in the theory of nonlinear elasticity in order to generate pulse solitary waves and also bulk travelling waves with compact support

OPTICAL AND PHOTOCATALYTIC PROPERTIES OF ELECTROSPUN ZnO FIBERS

ZnO nanofibers were obtained by electrospinning a solution of zinc acetate dihydrate and polyvinylpyrrolidone in N,N-dimethylformamide, followed by calcination at 500, 650 or 800 °C for 1 h. X-ray diffraction, selected area electron diffraction, scanning electron microscopy, transmission electron microscopy, reflectance spectroscopy and photoluminescence spectroscopy were used for the characterization of the resulting fibers. The thermally treated samples exhibit ZnO single phase with polycrystalline hexagonal structure. The morphological investigation revealed an accentuated contraction process during calcination, as well as the increase of the crystallite size and the appearance of a breaking tendency with the calcination temperature enhancement. Both UV and Visible emissions under excitation at 350 nm were showed by the optical studies, which also led to band gap values slightly lower than those reported for similar one-dimensional nanostructures. In order to assess the photocatalytic activity of ZnO fibers, the photodegradation of methylene blue in aqueous medium (10 -3 M) under UV irradiation (368 nm) was analyzed

Global generalized solutions for Maxwell-alpha and Euler-alpha equations

We study initial-boundary value problems for the Lagrangian averaged alpha models for the equations of motion for the corotational Maxwell and inviscid fluids in 2D and 3D. We show existence of (global in time) dissipative solutions to these problems. We also discuss the idea of dissipative solution in an abstract Hilbert space framework.Comment: 27 pages, to appear in Nonlinearit

Modular symbols in Iwasawa theory

This survey paper is focused on a connection between the geometry of $\mathrm{GL}_d$ and the arithmetic of $\mathrm{GL}_{d-1}$ over global fields, for integers $d \ge 2$. For $d = 2$ over $\mathbb{Q}$, there is an explicit conjecture of the third author relating the geometry of modular curves and the arithmetic of cyclotomic fields, and it is proven in many instances by the work of the first two authors. The paper is divided into three parts: in the first, we explain the conjecture of the third author and the main result of the first two authors on it. In the second, we explain an analogous conjecture and result for $d = 2$ over $\mathbb{F}_q(t)$. In the third, we pose questions for general $d$ over the rationals, imaginary quadratic fields, and global function fields.Comment: 43 page

The Inviscid Limit and Boundary Layers for Navier-Stokes Flows

The validity of the vanishing viscosity limit, that is, whether solutions of the Navier-Stokes equations modeling viscous incompressible flows converge to solutions of the Euler equations modeling inviscid incompressible flows as viscosity approaches zero, is one of the most fundamental issues in mathematical fluid mechanics. The problem is classified into two categories: the case when the physical boundary is absent, and the case when the physical boundary is present and the effect of the boundary layer becomes significant. The aim of this article is to review recent progress on the mathematical analysis of this problem in each category.Comment: To appear in "Handbook of Mathematical Analysis in Mechanics of Viscous Fluids", Y. Giga and A. Novotn\'y Ed., Springer. The final publication is available at http://www.springerlink.co

Examining agency governance in the European Union financial sector – a case-study of the European Securities and Markets Authority

Ever since the outset of the financial crisis of 2009, agencies have emerged as key actors of European Union (EU) financial sector governance. As an organisational form that can be insulated from national political pressures, and committed to the Union interest, agencies proliferated in the financial sector ushering the agencification trend in finance. In this sense, the European Securities and Markets Authority (ESMA) – as part of the European Supervisory Authorities – practically embodies this trend. ESMA presents a radical shift in financial markets’ governance due to the nature of its soft law regulations and the direct impact it exerts on addressees’ behaviour in emergency circumstances. But ESMA’s success in optimising financial sector governance largely depends on its legitimacy, which is centred on independence. At the same time independence demands wider participation and inclusiveness of the decision-making process. This is not easy to achieve in a complex system with multiple stakeholders as is the governance of the EU financial sector (e.g., EU institutions, national actors, private sector). This paper examines ESMA’s interinstitutional relations and independence in light of publicly voiced criticism. We find that ESMA’s main executive bodies are still susceptible to influences by Member States as well as EU institutions (i.e., Commission), which undermines its operational independence