Stability of periodic travelling shallow-water waves determined by Newton`s equation

We study the existence and stability of periodic travelling-wave solutions for generalized Benjamin-Bona-Mahony and Camassa-Holm equations. To prove orbital stability, we use the abstract results of Grillakis-Shatah-Strauss and the Floquet theory for periodic eigenvalue problems.

Universal Experimental Measurement System «Sun-Walker» : Automotive measurement system for the evaluation of the solar irradiation distribution for the tests of the solar concentrated systems.

This Thesis project is a part of the research conducted in Solar industry. ABSOLICON Solar Concentrator AB has invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate distribution of density of solar radiation in the focal line of the concentrated parabolic reflectors and to measure radiation from the artificial source of light being a calibration-testing tool.On the basis of the requirements of the company’s administration and needs of designing the concentrated reflectors the operation conditions for the Sun-Walker were formulated. As the first step, the complex design of the whole system was made and division on the parts was specified. After the preliminary conducted simulation of the functions and operation conditions of the all parts were formulated.As the next steps, the detailed design of all the parts was made. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Sun-Walker were assembled and tested. The software part, which controls the Sun-Walker work and conducts measurements of solar irradiation, was created on the LabVIEW basis. To tune and test the software part, the special simulator was designed and assembled.When all parts were assembled in the complete system, the Sun-Walker was tested, calibrated and tuned.

Reflection of matter waves in potential structures

In this paper the behavior of matter waves in suddenly terminated potential structures is investigated numerically. It is shown that there is no difference between a fully quantum mechanical treatment and a semiclassical one with regards to energy redistribution. For the quantum case it is demonstrated that there can be substantial reflection at the termination. The neglect of backscattering by the semiclassical method brings about major differences in the case of low kinetic energies. A simple phenomenological model is shown to partially explain the observed backscattering using dynamics of reduced dimensionality.

Localization in splitting of matter waves

In this paper we present an analysis of how matter waves, guided as propagating modes in potential structures, are split under adiabatic conditions. The description is formulated in terms of localized states obtained through a unitary transformation acting on the mode functions. The mathematical framework results in coupled propagation equations that are decoupled in the asymptotic regions as well before as after the split. The resulting states have the advantage of describing propagation in situations, for instance matter-wave interferometers, where local perturbations make the transverse modes of the guiding potential unsuitable as a basis. The different regimes of validity of adiabatic propagation schemes based on localized versus delocalized basis states are also outlined. Nontrivial dynamics for superposition states propagating through split potential structures is investigated through numerical simulations. For superposition states the influence of longitudinal wave-packet extension on the localization is investigated and shown to be accurately described in quantitative terms using the adiabatic formulations presented here.

Single-mode acceleration of matter waves in circular waveguides

Ultracold gases in ring geometries hold promise for significant improvements of gyroscopic sensitivity. Recent experiments have realized atomic and molecular storage rings with radii in the centimeter range, sizes whose practical use in inertial sensors requires velocities significantly in excess of typical recoil velocities. We use a combination of analytical and numerical techniques to study the coherent acceleration of matter waves in circular waveguides, with particular emphasis on its impact on single-mode propagation. In the simplest case we find that single-mode propagation is best maintained by the application of time-dependent acceleration force with the temporal profile of a Blackmann pulse. We also assess the impact of classical noise on the acceleration process.

Beyond sea, sun and fun in Rio de Janeiro: understanding exchange students motivations and interests

O objetivo deste estudo é compreender o que leva estudantes de intercâmbio ao Rio de Janeiro, quais são suas motivações e interesses que influenciam na escolha dessa cidade, um destino pouco tradicional para intercâmbios, que recebe um crescente número de intercambistas de países desenvolvidos. Também apresentamos uma discussão mais ampla sobre a educação internacional do século 21, posicionando programas de intercâmbio como uma das possíveis iniciativas para a internacionalização de instituições de ensino superior. Para responder essa questão, 20 estudantes de 11 países foram entrevistados. Os resultados indicam que existe muito mais no Rio de Janeiro além do sol e das belas praias. Há uma grande variedade de interesses que explicam porque estudantes de intercâmbio escolhem esse destino. O clichê sobre sol, praia e carnaval se manifestou em diversas respostas, no entanto, nunca como principal fator. Intercambistas se interessam pela cidade por diversos motivos além das atrações turísticas, como aprender português, melhorar o currículo e estar em uma economia emergente. Recomendações para a internacionalização de instituições de educação e uma agenda de pesquisa para o desenvolvimento desse tópico são apresentadas na parte final.

New challenges for international economic law teaching and research in México: Mexico’s outstanding waves of reforms

This position paper argues that at this time of Mexico’s ongoing big transformation, legal educators and researchers in Mexico need to pay greater attention to international economic law, and that a renewal and perhaps some re-orientation of the approach to teaching international economic law, could provide significant contributions to and shape and support both the objectives and outcomes of reform in Mexico. International Economic Law courses and research can be made more useful, not only for students themselves, but also for their contribution towards the role that academics, lawyers, and other epistemic communities need to play in the political, economic and social evolution that is accelerating in Mexico.