Particle Acceleration
Mostrando 13-24 de 33 artigos, teses e dissertações.
-
13. Análise de escala em bilhares com fronteiras móveis
We study numerically the scaling properties of some dynamical systems. Near the transition from the integrable to the non-integrable regime of complete e simplified versions of Fermi-Ulam model, we investigate the region of low energy (chaotic sea). We evaluate average quantities as functions (a) of the iteration number n or the time t, (b) of the initial ve
Publicado em: 2008
-
14. Acelaração do universo e criação gravitacional de matéria escura fria: novos modelos e testes observacionais
Recent astronomical observations (involving supernovae type Ia, cosmic background radiation anisotropy and galaxy clusters probes) have provided strong evidence that the observed universe is described by an accelerating, flat model whose space-time properties can be represented by the FriedmannRobertsonWalker (FRW) metric. However, the nature of the substanc
Publicado em: 2008
-
15. Comparison of turbulent particle dispersion models in turbulent shear flows
This work compares the performance of two Lagrangian turbulent particle dispersion models: the standard model (e.g., that presented in Sommerfeld et al. (1993)), in which the fluctuating fluid velocity experienced by the particle is composed of two components, one correlated with the previous time step and a second one randomly sampled from a Wiener process,
Brazilian Journal of Chemical Engineering. Publicado em: 2007-09
-
16. Plane symmetric bulk viscous domain wall in Lyra geometry
In this paper general solutions are found for domain walls in Lyra geometry in the plane symmetric spacetime metric given by Taub. Expressions for the energy density and pressure of domain walls are derived in both cases of uniform and time varying displacement field beta. Some physical consequences of the models are also given. Finally, the geodesic equatio
Brazilian Journal of Physics. Publicado em: 2007-09
-
17. Issuance of metals by motor vehicles and their effects on public health / Emissão de metais por veículos automotores e seus efeitos à saúde pública
Introduction: The presence of fine metal particles in the urban atmosphere is a big concern considering that a significant accumulation of these elements has been registered during the last decades. Information about metal level in the tailpipe is scarce and specific Brazilian emission references are basically inexistent. Objective. Experimentally characteri
Publicado em: 2007
-
18. Commissioning of the injector system of the IFUSP Microtron / "Início de operação e caracterização do sistema injetor do Mícrotron do IFUSP"
In this work we present the commissioning of the IFUSP Microtron injector system. We developed a new method to treat misalignments on a single lens as well as in a group of them. We installed an image acquisition system to acquire beam images from the fluorescent screen monitor. Emittance was measured and found to be (2,32 ± 0,05) pi.mm.mrad, independently
Publicado em: 2006
-
19. "MEDIDAS DE ESPALHAMENTO ELÁSTICO RESSONANTE 17O + p" / "MEASUREMENTS OF RESONANT ELASTIC SCATTERING 17O + p"
Foram medidas distribuições angulares do espalhamento elástico 17O + p e da reação de transferência p(17O,a)14N nas energias ECM = 1,39 e 2,33 MeV. Foi utilizado feixe de 17O produzido no Laboratório Pelletron, com energias de 25 e 42 MeV. As medidas foram efetuadas utilizando-se alvos plásticos de mylar aluminizado (C10H10O4) e polietileno (CH2) com
Publicado em: 2006
-
20. Is the cosmological particle production homogeneous?
Using a gauge-invariant formalism we find the density contrast equation in a cosmological scenario with particle production at the expenses of the gravitational field (open system cosmology). First, we find the modes for the density contrast considering that the particle production process participate of the inhomogeneities formation, and in a second phase t
Brazilian Journal of Physics. Publicado em: 2005-12
-
21. Irreversible processes and the accelerated-decelerated phases of the Universe
A model for the Universe is proposed where it is considered as a mixture of scalar and matter fields. The particle production is due to an irreversible transfer of energy from the gravitational field to the matter field and represented by a non-equilibrium pressure. This model can simulate three distinct periods of the Universe: (a) an accelerated epoch wher
Brazilian Journal of Physics. Publicado em: 2004-09
-
22. Propriedades microscopicas e macroscopicas de superficie em ligas ferrosas implantadas com nitrogenio
The understanding of cosmic radiation -the production/ acceleration mechanism and the propagation processes -involves the determination of three parameters: the energy of this radiation, its arrival direction and the chemical composition. These three tasks have challenged the experience, the skill and responsibility of several groups of particle physicists o
Publicado em: 2004
-
23. Modelos Efetivos para o Elétron / Effective Models for the Electron
We present two models for the electron in classical electrodynamics, which include some effects from quantum electrodynamics. In the first model, the electron is treated as an extended particle owing to the high-frequency oscillations (Zitterbewegung) of its electrical charge. We show that this model predicts correctly the magnitude of the electron spin and
Publicado em: 2003
-
24. Production of microencapsulados of starch with recobrimento in bed fluidizado / Produção de microencapsulados de amido com recobrimento em leito fluidizado
Thin polymeric layers, when applied to microcapsules, can increase the degree of protection and control the release of the contents. Starch microcapsules containing gelatin as binding material, obtained by spray drying, were filled with commercial fish oil by adsorption, and subsequently encapsulated, aimed at forming a film either with gelatin or with a mix
Publicado em: 2000