Monitored background radiometer

The infrared (IR) testing of the Olympus thermal model has provided a capability to perform cost effective thermal balance testing of satellites and satellite components. A high-accuracy monitored background radiometer was developed for the measurement of absorbed radiation heat flux encountered during IR thermal vacuum testing of spacecraft. The design, development, and calibration of this radiometer is described

Centralizers of maximal regular subgroups in simple Lie groups and relative congruence classes of representations

In the paper we present a new, uniform and comprehensive description of centralizers of the maximal regular subgroups in compact simple Lie groups of all types and ranks. The centralizer is either a direct product of finite cyclic groups, a continuous group of rank 1, or a product, not necessarily direct, of a continuous group of rank 1 with a finite cyclic group. Explicit formulas for the action of such centralizers on irreducible representations of the simple Lie algebras are given.Comment: 27 page

Manifestations cliniques du “burn out” chez les médecins

Dans cet article, l'auteur délimite les caractéristiques du burn out. Pour ce faire, iI fait un court historique du concept pour ensuite le définir par ses phases, ses symptômes cliniques, son étiologie et son traitement. Tout au long du texte, l'auteur appuiera ses dires sur des exemples tirés de la profession médicale.In this article, the author outlines the characteristics of "burn out". A short historical concept is presented and defined through its phases, clinical symptoms, etiology and treatment. Throughout his article, the author supports his thesis with drawn examples from the medical profession

The origin of the E+ transition in GaAsN alloys

Optical properties of GaAsN system with nitrogen concentrations in the range of 0.9-3.7% are studied by full-potential LAPW method in a supercell approach. The E+ transition is identified by calculating the imaginary part of the dielectric function. The evolution of the energy of this transition with nitrogen concentration is studied and the origin of this transition is identified by analyzing the contributions to the dielectric function from different band combinations. The L_1c-derived states are shown to play an important role in the formation of the E+ transition, which was also suggested by recent experiments. At the same time the nitrogen-induced modification of the first conduction band of the host compound are also found to contribute significantly to the E+ transition. Further, the study of several model supercells demonstrated the significant influence of the nitrogen potential on the optical properties of the GaAsN system.Comment: 5 pages, 3 figure

The rings of n-dimensional polytopes

Points of an orbit of a finite Coxeter group G, generated by n reflections starting from a single seed point, are considered as vertices of a polytope (G-polytope) centered at the origin of a real n-dimensional Euclidean space. A general efficient method is recalled for the geometric description of G- polytopes, their faces of all dimensions and their adjacencies. Products and symmetrized powers of G-polytopes are introduced and their decomposition into the sums of G-polytopes is described. Several invariants of G-polytopes are found, namely the analogs of Dynkin indices of degrees 2 and 4, anomaly numbers and congruence classes of the polytopes. The definitions apply to crystallographic and non-crystallographic Coxeter groups. Examples and applications are shown.Comment: 24 page

Illustrer le territoire québécois dans les manuels d’histoire au secondaire : étude de cas sur le paysage en tant qu’outil de médiation culturelle et ses rapports avec l’espace, le pouvoir et l’identité

Dans le présent article, nous proposons une réflexion sur l’usage du paysage dans trois manuels d’histoire québécois. Nous l’abordons premièrement en considérant le cadre de référence (ou le contexte de production) de ces documents visuels, de nature artistique, scientifique ou médiatique,relatifs à l’architecture. Nous analysons ces trois types de paysages pour discuter des rapports qu’ils entretiennent avec le réel, notamment concernant un certain effet d’authenticité et d’objectivité. Il s’agit alors de considérer le paysage en tant qu’outil de médiation culturelle. Nous poursuivons la réflexion sur l’usage du paysage par une analyse thématique de lieux associés à la ville de Montréal dans les manuels. Ensuite, nous présentons une grille de lecture des documents iconographiques qui pourrait s’appliquer à tout paysage considéré comme document iconographique pour susciter un questionnement productif sur le plan des informations que l’on peut en tirer. In this paper, we propose a reflection on the use of the landscape in three Quebec history textbooks. We turn first considering the terms of reference (or the context of production) of these visual documents, produced from an artistic, scientific or mediatic point of view. We analyze these three types of landscapes to discuss their relationship with reality, especially regarding some effect of authenticity and objectivity. It is then to consider the landscape as a tool for cultural mediation. We continue the reflection on the use of the landscape by a thematic analysis of places associated with the city of Montreal in textbooks. Thirdly, we present a reading grid of graphic materials that could be applied to any landscape considered as graphic material, in order to question it in terms of information that can be learned

Biofuels Production from Biomass by Thermochemical Conversion Technologies

Agricultural biomass as an energy resource has several environmental and economical advantages and has potential to substantially contribute to present days’ fuel demands. Currently, thermochemical processes for agricultural biomass to energy transformation seem promising and feasible. The relative advantage of thermochemical conversion over others is due to higher productivity and compatibility with existing infrastructure facilities. However, the majority of these processes are still under development phase and trying to secure a market share due to various challenges, right from suitable infrastructure, raw material, technical limitations, government policies, and social acceptance. The knowledge at hand suggests that biomass can become a sustainable and major contributor to the current energy demands, if research and development are encouraged in the field of thermochemical conversion for various agricultural biomass types. This paper intends to explore the physical and chemical characteristics of biofuel substitutes of fossil fuels, potential biomass sources, and process parameters for thermochemical conversion

Nonlinear magnetoinductive transmission lines

Power transmission in one-dimensional nonlinear magnetic metamaterials driven at one end is investigated numerically and analytically in a wide frequency range. The nonlinear magnetic metamaterials are composed of varactor-loaded split-ring resonators which are coupled magnetically through their mutual inductances, forming thus a magnetoiductive transmission line. In the linear limit, significant power transmission along the array only appears for frequencies inside the linear magnetoinductive wave band. We present analytical, closed form solutions for the magnetoinductive waves transmitting the power in this regime, and their discrete frequency dispersion. When nonlinearity is important, more frequency bands with significant power transmission along the array may appear. In the equivalent circuit picture, the nonlinear magnetoiductive transmission line driven at one end by a relatively weak electromotive force, can be modeled by coupled resistive-inductive-capacitive (RLC) circuits with voltage-dependent capacitance. Extended numerical simulations reveal that power transmission along the array is also possible in other than the linear frequency bands, which are located close to the nonlinear resonances of a single nonlinear RLC circuit. Moreover, the effectiveness of power transmission for driving frequencies in the nonlinear bands is comparable to that in the linear band. Power transmission in the nonlinear bands occurs through the linear modes of the system, and it is closely related to the instability of a mode that is localized at the driven site.Comment: 11 pages, 11 figures, submitted to International Journal of Bifurcation and Chao