Schooling and Ethnocultural Communities in Canada: Alternatives for Planning A Post-Modern Century

This essay examines trends in education that affect Canadian schools

ETIOLOGICAL CHARACTERISTICS OF ADENOVIRAL INFECTIONS IN THE DISTRICT OF VARNA, COVERING THE PERIOD 1969—1971

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Anisotropic Effects in Geometrically Isotropic Lattices

For spacings and element dimensions small with respect to wavelength the directric constant of a completely general lattice of identical elements may be represented by a tensor (k_e). In many applications of artificial dielectrics it is important that the dielectric act as an isotropic medium for microwaves. This requires that (k_e) reduce to a scalar. The dielectric constant tensor will reduce to a scalar only if the lattice is cubical and the geometry and the material of the elements is restricted so that the induced fields may be represented by a set of three mutually perpendicular static dipoles at the lattice points. Isotropy further requires that the moment of the resultant dipoles be proportional to the inducing field and that the proportionality factor be a scalar independent of direction. However, at shorter wavelengths, the representation of the lattice elements by static dipoles will not be valid and the medium becomes anisotropic. This paper evaluates the anisotropy produced by an arbitrary ratio of element spacing to wavelength, and demonstrates that there is a basic anisotropy associated with the granularity of an array composed of isotropic elements arranged in structurally isotropic patterns

World of Dying Dreams

Writings and artwork about gender discrimination in song lyrics and feminist musichttps://digitalcommons.chapman.edu/feminist_zines/1003/thumbnail.jp

Surface and Cytoskeletal Markers of Rostrocaudal Position in the Mammalian Nervous System

To identify cell surface molecules that define position in the mammalian nervous system, we previously characterized the binding of two monoclonal antibodies, ROCA1 and ROCA2, to adult rat sympathetic ganglia and intercostal nerves. The binding of ROCA1 is highest in rostral ganglia and nerves and declines in a graded manner in the caudal segments. ROCA2 labels the same cells in ganglia and nerves as ROCA1, but not in a position-selective manner. We now show by immunoblot analysis that ROCA1 recognizes two antigens in membrane/cytoskeletal fractions of peripheral nerves and ganglia: (1) a Triton X-100-insoluble, 60 kDa protein and (2) a Triton x-100- insoluble, 26 kDa protein. The 60 kDa protein is expressed at higher levels in rostral than in caudal intercostal nerves, and is identified as the intermediate filament protein peripherin. In contrast, it is the ROCA1 epitope on the 26 kDa protein, and not the protein itself, that is preferentially visualized immunohistochemically in rostral nerves and ganglia. We suggest that the ROCA1 epitope on the 26 kDa protein is masked in sections of caudal nerves and ganglia. Amino acid sequence data obtained from the affinity-purified 26 kDa protein indicate significant homology with human CD9, a cell surface protein implicated in intercellular signaling in hematopoietic cells. These results suggest that intermediate filament gene expression and epitope masking on the cell surface may be involved in functions related to position in the nervous system

Modélisation 0D pour la combustion dans les moteurs à allumage commandé : développements en proche paroi et dans le front de flamme

Recently, the interest for zero-dimensional models has increased. Indeed, these models provide easily the engines thermodynamic behavior and can be coupled with control tools. However, their accuracy must be improved to meet the current technological challenges. In the spark ignition engines, the premixed turbulent flame is modeled as a set of coherent flamelets. This approach requires special treatment near the walls, motivated by the modifications of the flame structure due to boundary layers. The present work proposes 0D modeling of combustion near the walls and in the reaction zone of the flame. To combustion model near the walls, the flame is divided into a free propagation contribution, and an interacting contribution with the walls. Each contribution is divided into a convective zone, wherein the entrainment of fresh gas is described, and a reaction zone, wherein the combustion reaction is modeled. Adding a reaction zone near the walls allows modeling a thermal gradient and a slower combustion reaction near the walls. To model the reaction zone, a flame discretization is made into several reaction zones. An engine operating range is simulated with our models, for quantifying the calibration parameters variability. To do this, models are calibrated on each operating point, by a method of minimization of the quadratic error on the heat released rate. Linear correlations can be found, depending on engines parameters. A good agreement between experimental data and simulation results is obtained with these parameters correlations.Depuis quelques années, les modèles 0D trouvent un regain d'intérêt auprès des motoristes. En effet, ces modèles, fournissant aisément un comportement thermodynamique du moteur, peuvent être couplés avec des outils de contrôle moteur. Néanmoins, leur précision doit être augmentée, pour répondre aux enjeux technologiques actuels. Dans les moteurs à allumage commandé, la flamme turbulente prémélangée est modélisée comme un ensemble de flammelettes cohérentes entre elles. Cette approche généraliste nécessite un traitement particulier en proche paroi, motivé par une modification de la structure de flamme due aux couches limites thermique et cinématique. Ce présent travail propose des approches de modélisations 0D de la combustion, en proche paroi et dans la zone réactionnelle de la flamme. Pour modéliser la combustion en proche paroi, la flamme est scindée en une contribution en propagation libre, et une contribution en interaction avec les parois. Chaque contribution est divisée en une zone de transport, dans laquelle l'entraînement des gaz frais est décrit, et une zone de réaction, dans laquelle la réaction de combustion est modélisée. L'ajout d'une zone de réaction en interaction avec les parois permet de modéliser un gradient de température et une réaction de combustion ralentie en proche paroi. Pour modéliser la zone réactionnelle, une discrétisation de la flamme en N zones de réaction indépendantes est proposée. Une plage de fonctionnement moteur a été simulée avec nos approches de modélisation, afin de quantifier la variabilité des paramètres de calibration. Pour ce faire, les modèles sont calibrés sur chaque point de fonctionnement, par une méthode de minimisation de l'erreur quadratique moyenne sur la loi de dégagement d'énergie. Des corrélations aisées de paramètres de calibration peuvent être établies, en fonction de paramètres moteurs. Les résultats de simulations, obtenus à partir de ces corrélations, sont satisfaisants

Anisotropic Effects in Geometrically Isotropic Lattices

The study of the dielectric properties of a lattice composed of identical metallic or dielectric elements of various geometries has re- ceived considerable attention in recent years in connection with the prac- tical application of such structures for polarizing devices, microwave lenses, and radome materials. It has been shown by the author1 that, for spacings and element dimensions small with respect to wavelength, the dielectric constant of a completely general uniform lattice of identical elements may be represented by a tensor (k_e) which may be written in functional form as (k_e) = f[(T), (δ)], where (T) is the structural anisotropy tensor which is related to the geometry of the lattice and (δ) is the polarizability tensor of the elements of the lattice. (δ) describes element anisotropy which may be due to material, the shape of the element, or both. An example of a lattice element displaying only material anisotropy is a ferrite or gaseous element of spherical shape immersed in a magnetostatic field. An example of shape anisotropy is the case of metallic or dielectric objects of non-spherical shape. In general, then, for spacing and element dimensions small compared to wavelength, there can be three orders of anisotropy in a lattice—structural or lattice anisotropy, material anisotropy, and anisotropy because of element shape. Examples of each type are described and discussed in detail in the aforementioned reference. A fourth order of anisotropy, which is related to the granularity of the lattice and be- comes important at higher frequencies will be described and investigated in this paper. It is usually important that the artificial material be as close as possible in physical properties to a real dielectric. This requires that it should be isotropic; that is, the structure should exhibit the same properties for a plane wave propagating through it in any direction. This behavior requires that (k_e) reduce to a scalar which, in turn, demands that (T) and (δ) become scalars, except for the special case in which the structural anisotropy of the array is compensated for by the element anisotropy in which case (k_e) is reduced to a scalar. The structural anisotropy tensor (T) will reduce to a scalar only if the lattice is cubical, while (δ) becomes a scalar only if the geometry and material of the lattice elements are so restricted that the induced fields may be represented by a set of three mutually perpendicular static dipoles on the lattice points.1 Isotropic behavior further requires that the moments of the resultant dipoles must be proportional to the inducing field. The proportionality factor is a scalar independent of direction. However, at shorter wavelengths the representation of the lattice elements by static dipoles will not be valid and the medium becomes anisotropic. The main objective of this paper is to evaluate the anisotropy produced by the finite ratio of wavelength to element spacing and to show that the Clausius-Mosotti relation so often used in predicting the properties of artificial lattice dielectrics is a satisfactory approximation only if the spacing is very small with respect to wavelength

The effect of holes and free edges on the stress in laminated plates

This work is concerned with the study of the mechanical behaviour of elastic laminated plates subjected to different boundary conditions. For the most part, each lamina is taken to be a fibre-reinforced material which contains a family of straight, continuously distributed fibres. When the modulus for extension in the fibre direction of each lamina is large compared with the other moduli, the laminate is termed 'highly anisotropic' and in such cases, approximate solutions can be obtained by treating the individual laminae as 'ideal' materials in the sense that they are inextensible in the fibre direction and also incompressible. In the context of the plane strain bending of a laminated cantilever, we show that the theory for ideal materials predicts the occurrence of singular fibres at the lateral surfaces of the laminate and at the interfaces between the individual laminae. In a highly anisotropic cantilever these fibres correspond to regions of high stress and accordingly a boundary layer theory is developed for these regions. The boundary layer solution, together with the ideal solution, provide a good approximation to the description of the response of the cantilever, but it is found to be inadequate near the intersections of edges and interfaces, and at corners. A separate investigation is made into the asymptotic behaviour of the stress in these regions. The major part of this thesis is concerned with the development of a general theory for laminated plates in stretching or bending. Given a laminate subject to specified boundary conditions, we define a single homogeneous equivalent plate which has material properties obtained. by an appropriate averaging of the material properties of each lamina. The equivalent plate is subjected to the same boundary conditions as the laminate and the equivalent displacements are determined by classical thin plate theory. The theory then assumes that the displacement components in each lamina can be expressed as the sum of the equivalent displacements and correction displacements. The correction solutions satisfy the conditions of displacement and traction continuity across the inter-laminar boundaries and the condition that the lateral surfaces of the plate are free from traction. In the special case of the laminae being isotropic, the solutions given by the theory exactly satisfy the full three-dimensional equations of linear elasticity. When the equivalent displacements are known, the complete solution in each lamina is readily determined and this is illustrated by examples. At the edges of the laminated plate, the prescribed boundary conditions are satisfied only in an average sense and therefore in these regions, an additional correction is required. The deviation of the calculated boundary condition from the specified boundary condition is used to determine the magnitude of this further correction

Three-Dimensional Lattices with Isotropic Dielectric Properties

Expressions are derived for the constitutive dielectric parameters of a cubical lattice whose elements consist of a triad of mutually perpendicular polarizable elements. The analysis gives the fundamental relations for the simulation by suitably disposed dipoles, of three-dimensionally isotropic dielectrics with dielectric constants greater than, equal to, and less than unity. Three different approaches have been used. One of these is a complete and rigorous solution which gives the dielectric tensor for the general case of unrestricted spacing to wavelength ratio. This rigorous analysis shows that the Clausius-Mosotti relation often used in predicting the properties of such lattices is a satisfactory approximation only if the spacing is very small with respect to wavelength. Using the general principles developed in the paper, conditions are derived for the realizability of reflectionless media