1,456 research outputs found

    First Documented Record of \u3ci\u3eOarisma Powesheik\u3c/i\u3e (Lepidoptera: Hesperiidae) in Canada

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    During a brief survey of the prairie areas near Vita, Manitoba, July 1985, Oarisma powesheik Parker was found to be abundant, although often local. Specimens collected constitute the first documented record for the species in Canada

    Explicit mixed strain–displacement finite elements for compressible and quasi-incompressible elasticity and plasticity

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    The final publication is available at Springer via http://dx.doi.org/ 10.1007/s00466-016-1305-zThis paper presents an explicit mixed finite element formulation to address compressible and quasi-incompressible problems in elasticity and plasticity. This implies that the numerical solution only involves diagonal systems of equations. The formulation uses independent and equal interpolation of displacements and strains, stabilized by variational subscales. A displacement sub-scale is introduced in order to stabilize the mean-stress field. Compared to the standard irreducible formulation, the proposed mixed formulation yields improved strain and stress fields. The paper investigates the effect of this enhancement on the accuracy in problems involving strain softening and localization leading to failure, using low order finite elements with linear continuous strain and displacement fields (P1P1 triangles in 2D and tetrahedra in 3D) in conjunction with associative frictional Mohr–Coulomb and Drucker–Prager plastic models. The performance of the strain/displacement formulation under compressible and nearly incompressible deformation patterns is assessed and compared to analytical solutions for plane stress and plane strain situations. Benchmark numerical examples show the capacity of the mixed formulation to predict correctly failure mechanisms with localized patterns of strain, virtually free from any dependence of the mesh directional bias. No auxiliary crack tracking technique is necessary.Peer ReviewedPostprint (author's final draft

    Stabilized mixed explicit finite element formulation for compressible and nearly-incompressible solids

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    El presente estudio presenta una formulación mixta de elementos finitos capaz de abordar problemas quasiincompresibles en forma explícita. Esta formulación se aplica a elementos con interpolaciones independientes e iguales de desplazamientos y deformaciones, estabilizadas mediante subescalas variacionales (VMS). Como continuación del estudio presentado en la referencia [23] , en la que se introdujo la subescala de las deformaciones, en este trabajo se incluyen los efectos de la sub-escala de los desplazamientos, con el fin de estabilizar el campo de las presiones. La formulación evita la condición de Ladyzhenskaya-Babuska-Brezzi (LBB) y sólo requiere la resolución de un sistema diagonal de ecuaciones. En este artículo se tratan también los principales aspectos de implementación. Finalmente, ejemplos de validación numérica muestran el comportamiento de estos elementos en comparación con la formulación irreducible.This study presents a mixed finite element formulation able to address nearly-incompressible problems explicitly. This formulation is applied to elements with independent and equal interpolation of displacements and strains, stabilized by variational subscales (VMS). As a continuation of the study presented in reference [23], in which the strains sub-scale was introduced, in this work the effects of sub-scale displacements are included, in order to stabilize the pressure field. The formulation avoids the Ladyzhenskaya-Babuska-Brezzi (LBB) condition and only requires the solution of a diagonal system of equations. The main aspects of implementation are also discussed. Finally, numerical examples validate the behaviour of these elements compared with the irreductible formulation.Peer ReviewedPostprint (published version

    The Deregulation of International Trucking in the European Union: Form and Effect

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    This paper examines how the deregulation of the international road transport industry in Western Europe has affected 1- the total quantity of cross-border road transport in the region; 2- the degree to which shippers outsource rather than integrate vertically their cross-border transport needs; and 3- the extent to which different countries participate in international road freight transport in Western Europe. Not surprisingly, we find that deregulation has had a large positive effect on the amount of international road transport net of the effect of the trade ties that grew over time among European Union countries. Moreover, consistent with the fact that the regulation disproportionately affected for-hire trucking, we find that deregulation has led shippers to shift toward more for-hire transport as opposed to own-account or private haulage. However, despite concerns voiced by member countries, we find no evidence that deregulation has disproportionately favored carriers of countries that were initially more (or less) intensively involved in international haulage

    The Deregulation of International Trucking in the European Union: Form and Effect

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    This paper examines how the deregulation of the international road transport industry in Western Europe has affected 1- the total quantity of cross-border road transport in the region; 2- the degree to which shippers outsource rather than integrate vertically their cross-border transport needs; and 3- the extent to which different countries participate in international road freight transport in Western Europe. Not surprisingly, we find that deregulation has had a large positive effect on the amount of international road transport net of the effect of the trade ties that grew over time among European Union countries. Moreover, consistent with the fact that the regulation disproportionately affected for-hire trucking, we find that deregulation has led shippers to shift toward more for-hire transport as opposed to own-account or private haulage. However, despite concerns voiced by member countries, we find no evidence that deregulation has disproportionately favored carriers of countries that were initially more (or less) intensively involved in international haulage

    Spousal support and relationship happiness in adults with type 2 diabetes and their spouses

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    Objectives The purpose of this study was to examine the association between the perceptions of spousal support self-efficacy in terms of dietary self-care and relationship happiness. Methods Forty-six couples, in which only one spouse has type 2 diabetes, completed questionnaires on perceptions of spousal support self-efficacy and relationship happiness. Results Using an actor-partner interdependence model, we found that when persons with type 2 diabetes were more confident in their spouse’s ability to provide them with support regarding their dietary self-care, they reported more relationship happiness. We also found that when their spouse without diabetes was more confident in their own abilities to provide such support to their partner, they reported more relationship happiness. However, the person with diabetes’ confidence in their spouse’s support abilities and the spouse’s confidence in their own support abilities were not associated with the other partner’s relationship happiness. Conclusions This study offers a unique dyadic perspective on the determinants of happiness for couples in which one spouse has type 2 diabetes. The perceived quality of spousal support appears to be associated with relationship happiness in committed couples managing diabetes, regardless of the actual support received or provided

    A stabilized mixed explicitformulation for plasticity with strain localization

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    Este artículo presenta la aplicación de la formulación mixta estabilizada explícita en desplazamientos y deformaciones (MEX-FEM) [23,24] para la solución de problemas no lineales de la mecánica de sólidos con localización de deformaciones. A fin de emplear el mismo orden lineal de interpolación para el campo de los desplazamientos y deformaciones, nuestra formulación emplea el método de las sub-escalas variacionales. Comparada con la formulación estándar en desplazamientos, la formulación propuesta proporciona mejores campos de deformaciones y tensiones, y es capaz de abordar situaciones quasi-incompresibles. En este trabajo se investigan los efectos que tienen las deformaciones y tensiones mejoradas en los modelos de plasticidad de Mohr-Coulomb y Drucker Prager, incluyendo el fenómeno de la localización de las deformaciones. Los ejemplos numéricos validan la capacidad de la formulación propuesta para predecir correctamente los mecanismos de fallo, cargas últimas y la dirección de la banda de localización, virtualmente independientes de la malla utilizada y sin necesidad de emplear un algoritmo de rastreo.This paper presents the application of stabilized mixed explicit strain/displacement formulation (MEX-FEM) [23,24] for solving non-linear plasticity problems in solid mechanics with strain localization. In order to use the same linear interpolation order for displacements and strains, the formulation uses the variational subscales method. Compared to the standard irreducible formulation, the proposed formulation yields improved strain and stress fields, and it is capable of addressing nearly incompressible situations. This work investigates the effects of the improved strain and stress fields in problems involving strain softening and localization leading to failure for the Mohr-Coulomb and Drucker Prager plasticity models. Numerical examples validate the ability of the proposed formulation to correctly predict failure mechanisms with localized patterns of strain, virtually free of mesh dependence and without using tracking algorithm.Peer ReviewedPostprint (published version

    Assay, Purification, and Partial Characterization of Choline Monooxygenase from Spinach

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