Congrès International d'Architecture Moderne

About: Congrès International d'Architecture Moderne is a based out in . It is known for research contribution in the topics: Boundary value problem & Jet (fluid). The organization has 393 authors who have published 403 publications receiving 4104 citations.

Conformal mapping of unbounded multiply connected regions onto logarithmic spiral slit with infinite straight slit

Abstract: This paper presents a boundary integral equation method with the adjoint generalized Neumann kernel for conformal mapping of unbounded multiply connected regions. The canonical region is the entire complex plane bounded by an infinite straight slit on the line Im ω = 0 and finite logarithmic spiral slits. Some linear boundary integral equations are constructed from a boundary relationship satisfied by an analytic function on a multiply connected region. These integral equations are uniquely solvable. The kernel involved in these integral equations is the adjoint generalized Neumann kernel.

Plant breeding as tool to challenge climatic changes in forage production. a review = la mejora genética vegetal como herramienta para afrontar los cambios climáticos en la producción de forraje. una revisión

Abstract: Literature was reviewed concerning climatic changes, especially increase in carbon dioxide concentration [CO2] and temperature during the last centuries, and connecting these changes with biochemical pathways in plants, mainly photosynthesis activity and respiration. Plant breeding has been successful in moving the genome of plants for selecting different characteristics, such as high oil and protein of the maize kernel, increase of yield in several crops along different eras, resistance to diseases and pests and adaptation to environmental conditions. Therefore plant breeding is proposed as a tool to challenge the climatic change through development of new varieties with complex traits adapted to future environments, such as higher temperatures and lower rainfall. Utilization of natural or induced polyploidy has demonstrated to be a good aid to increase vigor, yield, resistance to diseases, and adaptation of forage crops to stress. Development of synthetic varieties for forage plants seems to be a good option for achieving breeding goals in cross-pollinated crops. Hybridization between different species and within species is sometimes used for increasing the vigor, the adaptation to environmental stress and the yield of cultivars. Hybrids between two species (e.g., from genus Lolium) produce usually a high rate of aneuploid plants in the F1 generation. Recurrent selection for raising the rate of balanced euploid plants in the F1, F2, F3, F4…generations of the aloploid hybrids is needed for getting stable varieties adapted to the target stress. Commercial hybrid seed is preferred to synthetics provided that the additional yield and features compensate the extra cost of seed production. Results of forage maize hybrids related to the worldwide cultivated “B73 × Mo17” hybrid, which were selected for earliness, are presented. Exploration of new C4 tropical species, such as Teff, likely will help to produce forage in poor watering conditions. The use of 13C isotopic discrimination seems to be a good indicator to breed for water use efficiency (WUE) in C3 plants. Biotechnological tools, such as molecular markers, will facilitate to achieve breeding objectives sooner. Breeding suggestions for development of new varieties in C3 and C4 species adapted to future environments should consider the possible biotic and abiotic stresses generated by the climatic change. Automated phenotyping platforms are used for simulating stress environments. Domestication of wild species may be an alternative for developing a new crop to meet the requirement of environmental change. Crop domestication is a difficult task; however the use of rational strategies, including breeding for reducing the effect of limiting factors and strengthening favorable traits will help to achieve the desired objectives. Use of autochthonous germplasm as base material is crucial for providing genetic variability and genes adapted to environmental conditions. RESUMEN Se reviso la literatura en lo referente al cambio climatico, especialmente al aumento de la concentracion de dioxido de carbono [CO2] y la temperatura durante los ultimos siglos, asi como su relacion con las rutas bioquimicas en plantas, principalmente la actividad fotosintetica y la respiracion. La mejora genetica de plantas ha tenido exito en cambiar el genoma de las plantas seleccionando diversas caracteristicas, tales como alto contenido de aceite y proteina en el grano de maiz, aumento del rendimiento en varios cultivos durante diferentes eras, resistencia a plagas y enfermedades y adaptacion a las condiciones ambientales. Por lo tanto se propone a la mejora genetica de plantas como una herramienta util para afrontar el cambio climatico mediante el desarrollo de nuevas variedades con caracteres complejos adaptados a los ambientes futuros. La utilizacion de la poliploidia natural o inducida ha demostrado ser una buena ayuda para aumentar el vigor, rendimiento, resistencia a enfermedades y adaptacion de cultivos forrajeros a estres. El desarrollo de variedades sinteticas en plantas pratenses parece ser una buena opcion para alcanzar los objetivos de mejora en cultivos de polinizacion cruzada. La hibridacion entre especies y dentro de especies gramineas y leguminosas forrajeras se utiliza para aumentar el vigor, la adaptacion al estres y el rendimiento de las variedades. Hibridos entre dos especies (e.g. del genero Lolium) producen generalmente una alta tasa de plantas aneuploides en la generacion F1. La seleccion recurrente para elevar la tasa de plantas euploides (i.e. con equilibrio cromosomico) en las generaciones F1, F2, F3, F4… del hibrido aloploide es necesaria para obtener variedades estables adaptadas al estres. La semilla hibrida comercial se prefiere a las variedades sinteticas siempre que el incremento del rendimiento y otras caracteristicas compensen el coste adicional de produccion de semilla. Se presentan los resultados de hibridos de maiz forrajero relacionados con el hibrido ampliamente cultivado B73 x Mo17 y seleccionados para precocidad. La exploracion de nuevas especies tropicales C4, tal como Teff, ayudara probablemente a producir forraje en condiciones de sequia y calor. El uso de la discriminacion isotopica 13C parece ser un buen indicador para mejorar la eficiencia en el uso del agua (EUA) en plantas C3. Las herramientas biotecnologicas, tales como marcadores moleculares, facilitaran alcanzar mas pronto los objetivos de mejora genetica. Se sugiere que la mejora genetica durante el proceso de desarrollo de nuevas variedades en plantas C3 y C4 adaptadas a los ambientes futuros debera tener en cuenta los estreses bioticos y abioticos generados por el cambio climatico. La domesticacion de especies silvestres puede ser una alternativa para obtener un nuevo cultivo que cumpla los requisitos del cambio ambiental. Plataformas automatizadas de fenotipado se utilizan para simular ambientes de estres. La domesticacion para desarrollar un cultivo es una tarea dificil; sin embargo el uso de estrategias racionales, incluyendo la mejora genetica para conseguir eliminar factores limitantes y fortalecer los rasgos favorables ayudara a lograr los objetivos deseados. El uso de germoplasma autoctono como material base es esencial para proporcionar variabilidad genetica y genes adaptados a las condiciones ambientales.

Estimation of Design Thermal Integrity

Abstract: Working capacity of machine parts in various possible operation conditions must be maintained by introduction of strength and durability margins (safety factors). These margins are necessary in view of possible random industrial deviations, unforeseen adverse combinations of loads, temperatures, and operating time at some regimes, and many other reasons. General principles for safety factor formation require analyzing the most probable ways for deviation of stresses, temperatures, and work duration or any other specific parameter, over its design value—on separateness or in aggregate with other ones. The possibility of creating a design of “equal strength” at non-isothermal loading is illustrated by the optimization of a turbomachine blade model non-uniformly heated along its length. The benefits of introducing a “weak link” that reaches destruction under overload before the entire system are discussed. It is shown that “equivalent” trials replicating the lifetime of the system can significantly accelerate the verification of the most stressed machine parts. The trials ensure a machine functioning with the same safety factors as under the work conditions, but during smaller duration. The cyclic durability margins for non-isothermal cyclic fatigue, taking into account influence of exposure at the maximum cycle temperature and asymmetric loading, are considered. Along with the evaluation of local strength and durability margins for the most stressed elements of a structure, computation methods, on a bearing ability of the structure “in whole,” are stated. Use of the determined safety factors is shown to be principally necessary for the reliable probabilistic estimation of details’ low-cycle fatigue (LCF). For this purpose, rational methods for generation of probabilistic-statistical strength and durability margins of machine parts, using results of the limited scope of sampling tests, are proposed.

Numerical Simulation of the Turbulent Combustion of a Methane Air Mixture Using Les

Abstract: The methodology of turbulent combustion simulation is presented. The methodology is based on large eddy simulation coupled with a global reaction. The numerical simulation of a flow in a laboratory combustion chamber is performed. The effect of the constants of the model’s rate of chemical reactions on the results of the calculations is analyzed. It is shown that the methodology ensures close agreement between the numerical and experimental results in the laboratory’s combustion chambers.

Unsteady Thermal Plasticity

Abstract: A topic of this chapter is the general approach to computation analysis of unsteady elastoplastic deformations in machine parts and mechanical systems under non-isothermal loading, based on modern experimental data and theoretical developments. It is shown that widespread variants of theories of plasticity, including strain hardening model, enable satisfactory evaluation of the plastic strain rate, associated with transient processes, only provided that strains increase along an invariable direction. The theory of stabilized anisotropic hardening (SAH theory) developed over the last few decades is outlined. This theory takes into consideration loading history and material adaptability along with separation of stresses into so-called active and residual micro-stress parts. A comparison with numerous experimental results demonstrates efficiency of the SAH theory for calculating the plastic strain rate under sign-varying multi-axial proportional loading. An experimentally justified extension of the SAH theory proposed by the author for analyzing more elaborate case of non-proportional (out-of-phase) non-isothermal loading and conditionally named “the model of stabilized anisotropic-ray hardening” (the SARH theory) is described in detail. The theory starts from the concept of the evolvement of anisotropy deformation along a “hardening axis,” which is collinear to a varying vector of the aforementioned active stresses, and also relies on separation of residual micro-stresses into steady (isotropic) and unsteady (anisotropic) parts; in doing so, unsteady micro-stresses vary under rotation of the hardening axis. The constitutive relations written in the form of the projections of micro-stresses, plastic strains, and their increments onto this axis govern arbitrary non-isothermal deformations. A step-by-step procedure of numerical solution of a thermal plasticity problem using the SARH model is also described. Numerical examples illustrate the applicability of the proposed fairly simple model for restoring the plastic strain rate and direction of plastic strain observed for specimens loaded over a wide range of magnitudes and orientations of the stress vector. The possibility of estimating damage accumulation and failure conditions is addressed for general elastoplastic non-isothermal process. A brief survey of the publications (both in Russian and English) on the SAH theory of elastic plastic deformations of solids subject to sign-varying loading is presented.