Investigation on average void fraction for air/non-Newtonian power-law fluids two-phase flow in downward inclined pipes

The present work has been carried out to investigate on the average void fraction of gas/non-Newtonian fluids flow in downward inclined pipes. The influences of pipe inclination angle on the average void fraction were studied experimentally. A simple correlation, which incorporated the method of Vlachos et al. for gas/Newtonain fluid horizontal flow, the correction factor of Farooqi and Richardson and the pipe inclination angle, was proposed to predict the average void fraction of gas/non-Newtonian power-law stratified flow in downward inclined pipes. The correlation was based on 470 data points covering a wide range of flow rates for different systems at diverse angles. A good agreement was obtained between theory and data and the fitting results could describe the majority of the experimental data within ±20%.

Verification of a scaling law in few-cycle laser pulses

The scaling law of photoionization in few-cycle laser pulses is verified in this paper. By means of numerical solution of time-dependent Schrodinger equation, the photoionization and the asymmetry degree of photoionization of atoms with different binding potential irradiated by various laser pulses are studied. We find that the effect of increasing pulse intensity is compensated by deepening the atomic binding potential. In order to keep the asymmetric photoionization unchanged, if the central frequency of the pulse is enlarged by k times, the atomic binding potential should also be enlarged by k times, and the laser intensity should be enlarged by k(3) times. (c) 2005 Optical Society of America.

A scaling law of photoionization in ultrashort pulses

By means of the numerical solution of time-dependant Schrodinger equation, we verify a scaling law of photoionization in ultrashort pulses. We find that for a given carrier-envelope phase and duration of the pulse, identical photoionizations are obtained provided that when the central frequency of the pulse is enlarged by k times, the atomic binding potential is enlarged by k times, and the laser intensity is enlarged by k(3) times. The scaling law allows us to reach a significant control over direction of photoemission and offers exciting prospects of reaching similar physical processes in different interacting systems which constitutes a novel kind of coherent control.

A scaling law of photoelectron angular distributions in one-cycle laser pulses

The photoelectron angular distributions (PADs) from above-threshold ionization of atoms irradiated by one-cycle laser pulses satisfy a scaling law. The scaling law denotes that the main features of the PADs are determined by four dimensionless parameters: (1) the ponderomotive number u(p) = U-p/hw, the ponderomotive energy U-p in units of laser photon energy; (2) the binding number E-b = E-b/h(w), the atomic binding energy E-b in units of laser photon energy; (3) the number of absorbed photons q; (4) the carrier-envelope phase phi(0), the phase of the carrier wave with respect to the envelope. We verify the scaling law by theoretical analysis and numerical calculation, compared to that in long-pulse case. A possible experimental test to verify the scaling law is suggested.

Modified formula of Malus' law for Glan-Taylor polarizing prisms

A simple three-axis model has been developed, which has been successfully applied to the analysis of the light transmittance in spatial incident angle and the simulation of modified formula of Malus' law for Glan-Taylor prisms. Our results indicate that the fluctuations on the cosine squared curve are due to specific misalignments between the axis of the optical system, the optical axis of the prism and the mechanical axis (rotation axis) of prism, which results in the fact that different initial relative location of the to-be-measured-prism in the testing system corresponds to different shape of Malus' law curve. Methods to get absolutely smooth curve are proposed. This analysis is available for other kinds of Glan-type prisms. (C) 2004 Elsevier B.V. All rights reserved.

A scaling law of photoionization in few-cycle regime

In this paper, a scaling law of photoionization of atoms irradiated by intense, few- cycle laser pulses is established. The scaling law sets a relation to the phase- dependent ionization with the kinetic energy of photoelectrons, the duration and peak intensity of short pulses, and the ionization potential of the target atoms. We find that it will be advantageous to manifest the phase- dependent photoionization by choosing the target atoms with larger ionization potential, using laser with smaller carrier- frequency, and increasing the pulse intensity. (c) 2007 Optical Society of America.

Can the dead speak? appropriation and rewriting of the canon in Angela Carters Nights at the circus and in Margaret Atwoods The Penelopiad

Esta dissertação visa estudar como autoras pós-modernas se apropriam e reescrevem textos canônicos em uma tentativa de trazer à tona e desconstruir as metanarrativas patriarcais, que informam tais textos. Tal objetivo pretende ser alcançado através de um estudo sobre a formação do cânone literário, dos conceitos de mito e principalmente das estratégias narrativas utilizadas por essas autoras em seu processo criativo. Para tal, um estudo sobre intertextualidade, a paródia e a intertextualidade paródica é levado a cabo nesta dissertação. Dois romances figuram como objeto de investigação neste trabalho. O romance Nights at the Circus, da escritora inglesa Angela Carter, é o primeiro a ser analisado. Nesse romance, as estratégias de apagamento das fronteiras entre os gêneros e a intertextualidade paródica entre textos e mitos clássicos como formas de apropriação e subversão do cânone, são privilegiadas. O outro romance que se faz presente nesta dissertação é a obra da autora canadense Margaret Atwood intitulada The Penelopiad. Nesse romance, personagens que antes eram marginalizados ou não tinham voz figuram como personagens principais, como é o caso de Penélope e de suas doze criadas. Esta dissertação visa, assim, mostrar como essas apropriações de textos canônicos exercem um papel fundamental no questionamento da artificialidade de discursos que são naturalizados e dos valores propagados pelos mesmos

Addressing students' difficulties with Faraday's law: A guided problem solving approach

In traditional teaching, the fundamental concepts of electromagnetic induction are usually quickly analyzed, spending most of the time solving problems in a more or less rote manner. However, physics education research has shown that the fundamental concepts of the electromagnetic induction theory are barely understood by students. This article proposes an interactive teaching sequence introducing the topic of electromagnetic induction. The sequence has been designed based on contributions from physics education research. Particular attention is paid to the relationship between experimental findings (macroscopic level) and theoretical interpretation (microscopic level). An example of the activities that have been designed will also be presented, describing the implementation context and the corresponding findings. Since implementing the sequence, a considerable number of students have a more satisfactory grasp of the electromagnetic induction explicative model. However, difficulties are manifested in aspects that require a multilevel explanation, referring to deep structures where the system description is better defined.

A subcidadania e o Direito: da sociologia da inautenticidade à modernização seletiva

Este trabalho tem como objetivo discutir a existência de uma subcidadania brasileira e suas repercussões para o campo do direito. Para isso, decidiu-se trabalhar com a tese do sociólogo Jessé Souza de que o Brasil teria vivido uma modernização seletiva, que ao importar as práticas modernas sem uma correspondente homogeneização das classes sociais, teria relegado pelo menos um terço da população à subcidadania. Após realizar uma análise crítica desta tese, confrontando-a ainda com o que seria, para o próprio Jessé Souza, o cânone tradicional de interpretação do Brasil, formado pelas obras de Sérgio Buarque de Holanda, Raymundo Faoro e Roberto DaMatta, procurou-se refletir sobre as repercussões da tese da modernização seletiva para o campo do direito. Sob a chave de que a cidadania, entendida como uma igual dignidade, é a próprio fundamento dos direitos, discutiu-se que a existência de uma subcidadania no Brasil deveria ser levada em conta pelo campo do direito, tanto para se problematizar a distância entre a positivação dos institutos e sua concretização como para promover uma abertura do direito às lutas por reconhecimento e cidadania