Cosmopolitan Theory: Examining the (Dis-)location of Imagology

Being interdisciplinary, reflexive and analytical, theory has practical effects, questioning assumptions such as those related to discourse, meaning or identity, and exploring the circumstances in which texts are produced. It offers new conceptual tools and provides an argumentative method. Fields such as imagology have benefitted from the outset from the variety of theories reflecting the intellectual progress of their times, in particular in connection with the study of the relationship between Self and Other, thus providing new perspectives on the uses of preconceived ideas in artistic, written and visual, representations. In view of the current context of migratory flows and societal upheavals, it seems topical to examine the theories feeding the field of imagology today. Traditionally, history, psychology and sociology have proved instrumental in the building of essential notions pertaining to the sphere. More recently, studies have drawn on new approaches connected to reception, translation, gender and education studies, widening the imagological scope and its range of methodological tools. This article examines the nature of the imagological undertaking, its current spread worldwide, and shows how this comparative literary field upholds a cosmopolitan ethos.

Perpendicular Diffusion of Energetic Particles: A Complete Analytical Theory

Over the past two decades scientists have significantly improved our understanding of the transport of energetic particles across a mean magnetic field. Due to test-particle simulations, as well as powerful nonlinear analytical tools, our understanding of this type of transport is almost complete. However, previously developed nonlinear analytical theories do not always agree perfectly with simulations. Therefore, a correction factor a 2 was incorporated into such theories with the aim to balance out inaccuracies. In this paper a new analytical theory for perpendicular transport is presented. This theory contains the previously developed unified nonlinear transport theory, the most advanced theory to date, in the limit of small Kubo number turbulence. New results have been obtained for two-dimensional turbulence. In this case, the new theory describes perpendicular diffusion as a process that is sub-diffusive while particles follow magnetic field lines. Diffusion is restored as soon as the turbulence transverse complexity becomes important. For long parallel mean-free paths, one finds that the perpendicular diffusion coefficient is a reduced field line random walk limit. For short parallel mean-free paths, on the other hand, one gets a hybrid diffusion coefficient that is a mixture of collisionless Rechester & Rosenbluth and fluid limits. Overall, the new analytical theory developed in the current paper is in agreement with heuristic arguments. Furthermore, the new theory agrees almost perfectly with previously performed test-particle simulations without the need of the aforementioned correction factor a 2 or any other free parameter.

Acoustic microstreaming produced by two interacting gas bubbles undergoing axisymmetric shape oscillations

An analytical theory is developed that describes acoustic microstreaming produced by two interacting bubbles. The bubbles are assumed to undergo axisymmetric oscillation modes, which can include radial oscillations, translation and shape modes. Analytical solutions are derived in terms of complex amplitudes of oscillation modes, which means that the modal amplitudes are assumed to be known and serve as input data when the velocity field of acoustic microstreaming is calculated. No restrictions are imposed on the ratio of the bubble radii to the viscous penetration depth and the distance between the bubbles. The interaction between the bubbles is considered both when the linear velocity field is calculated and when the second-order velocity field of acoustic microstreaming is calculated. Capabilities of the analytical theory are illustrated by computational examples.

Machinery Foundations Dynamical Analysis: A Case Study on Reciprocating Compressor Foundation

A faulty dynamical interaction between a machine and a foundation can lead to unexpected and dangerous failures, impacting human lives and the environment. Some machines, as reciprocating compressors, have a low rotation speed; this can lead to dangerous frequency for the foundation blocks. For this reason, a careful analysis shall be done during the design phase to avoid the range of the frequency of resonances and low vibration speeds. Designers can approach this problem by relying both on Analytical Theory and Finite Element Analysis. This article compares these methods by studying the dynamical response of different foundation geometries in a case study of a reciprocating compressor foundation. The applicability limits of Analytical theory are explored and an evaluation of the difference in the estimation of natural frequencies of the system using Analytical Theory and Finite Elements Analysis are made for different foundation geometries. The comparison shows similar results until the foundation geometry is rigid; reference geometries limits are provided so that designers can choose which of the methods better suits their type of analysis.

Analytical theory of high-speed nonequilibrium in a binary mixture of gases with a predominant light component

Analytical estimates are obtained that allow, first of all, to determine the fundamental conditions for the existence of a high-speed effect. In addition, an analytical assessment of the greatest value of this effect is given.