Optimization of lumping schemes for plane square quadratic finite element in elastodynamics

The effectiveness of explicit direct time-integration methods is conditioned by using diagonal mass matrix which entails significant computational savings and storage advantages. In recent years many procedures that produced diagonally lumped mass matrices were developed. For example, the row sum method and diagonal scaling method (HRZ procedure) can be mentioned. In this paper, the dispersive properties of different lumping matrices with variable mass distribution for the plane square 8-node serendipity elements are investigated. The dispersion diagrams for such lumping matrices are derived for various Courant numbers, wavelengths and the directions of wave propagation

Dispersion of elastic waves in the contact–impact problem of a long cylinder

AbstractNumerical dispersion of two-dimensional finite elements was studied. The outcome of the dispersion study was verified by the numerical and analytical solutions to the longitudinal impact of two long cylindrical bars. In accordance with the results of the dispersion analysis it was demonstrated that the quadratic elements showed better accuracy than the linear ones

Full Field Computing for Elastic Pulse Dispersion in Inhomogeneous Bars

In the paper, the finite element method and the finite volume method are used in parallel for the simulation of a pulse propagation in periodically layered composites beyond the validity of homogenization methods. The direct numerical integration of a pulse propagation demonstrates dispersion effects and dynamic stress redistribution in physical space on example of a one-dimensional layered bar. Results of numerical simulations are compared with analytical solution constructed specifically for the considered problem. Analytical solution as well as numerical computations show the strong influence of the composition of constituents on the dispersion of a pulse in a heterogeneous bar and the equivalence of results obtained by two numerical methods

Efecto del sistema de labranza y la fertilización nitrogenada sobre el rendimiento de maíz (Zea mays l.) en un haplustol éntico de la región semiárida pampeana = Effect of tillage and nitrogen fertilization on corn yield (Zea mays l.) in an entic haplustol of the semiarid pampa

El objetivo de este trabajo fue evaluar el efecto de la fertilización nitrogenada sobre el rendimiento de maíz (Zea mays L.) en siembra directa (SD) y en siembra convencional (SC). Para ello se llevó a cabo un ensayo a campo en parcelas dividas en el cual el factor principal era sistema de labranza (SD, SC) y el factor secundario la dosis de fertilización nitrogenada (0, 60, 120 y 180 kg.ha-1). La determinación de humedad y de los contenidos de nitrógeno de nitratos en el suelo se realizó en intervalos de 20 cm hasta los 60 cm de profundidad. Los momentos de muestreo fueron en V2 (16/12), V6 (15/1), floración (11/2) y madurez fisiológica (28/4). La fertilización no afectó los rendimientos de maíz en SD cuando las dosis fueron bajas, pero a altas dosis los rendimientos fueron significativamente mayores. En SC los rendimientos variaron significativamente ante menores dosis. Los rendimientos fueron mayores en SD que en SC, comparando los mismos tratamientos de fertilización. Esto se pudo explicar ya que en siembra directa habría mayores contenidos hídricos, mayor mineralización del nitrógeno y menores pérdidas de este elemento por lixiviación.The objective of this study was to evaluate the effect of nitrogen (N) fertilization on corn grain yield (Zea mays L.) under zero tillage (SD) and conventional tillage (SC). For this purpose, a field assay using a split-plot experimental design was carried out relying on tillage system (SD, SC) as main factor and N fertilization rate (0, 60, 120, 180 kg N/ha) as secondary factor. Soil moisture and nitrate-N contents were determined at 20 cm intervals to a depth of 60 cm. This followed sampling done at crop phenological stages V2 (16 December), V6 (15 January), flowering (11 February) and physiological maturity (28 April). For SD system, corn yield was not affected by N fertilization at low rates but differed significantly at high rates, while yields for SC were different even at low rates. Considering the same fertilization treatments, yields for SD were always higher than those for SC. These results might be explained by the higher moisture contents and mineralization rates, and lower N lixiviation losses, for soil under SD system.EEA AnguilFil: Civalero, Agustín. Universidad Nacional de La Pampa. Facultad de Agronomía; Argentina.Fil: Kolman, Gabriel Yeshu. Universidad Nacional de La Pampa. Facultad de Agronomía; ArgentinaFil: Fernandez, Romina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentina. Universidad Nacional de La Pampa. Facultad de Agronomía; Argentina.Fil: Noellemeyer, Elke. Universidad Nacional de La Pampa. Facultad de Agronomía; Argentin

Efecto del sistema de labranza y la fertIización nitrogenada sobre el rendimiento de maíz (Zea mays l.) en un haplustol éntIco de la región semIárIda pampeana

El objetivo de este trabajo fue evaluar el efecto de la fertilización nitrogenada sobre el rendimiento de maíz (Zea mays L.) en siembra directa (SD) y en siembra convencional (SC). Para ello se llevó a cabo un ensayo a campo en parcelas dividas en el cual el factor principal era sistema de labranza (SD, SC) y el factor secundario la dosis de fertilización nitrogenada (0, 60, 120 y 180 kg.ha-1 ). La determinación de humedad y de los contenidos de nitrógeno de nitratos en el suelo se realizó en intervalos de 20 cm hasta los 60 cm de profundidad. Los momentos de muestreo fueron en V2 (16/12), V6 (15/1), floración (11/2) y madurez fisiológica (28/4). La fertilización no afectó los rendimientos de maíz en SD cuando las dosis fueron bajas, pero a altas dosis los rendimientos fueron significativamente mayores. En SC los rendimientos variaron significativamente ante menores dosis. Los rendimientos fueron mayores en SD que en SC, comparando los mismos tratamientos de fertilización. Esto se pudo explicar ya que en siembra directa habría mayores contenidos hídricos, mayor mineralización del nitrógeno y menores pérdidas de este elemento por lixiviación

Attributable deaths and disability-adjusted life-years caused by infections with antibiotic-resistant bacteria in the EU and the European Economic Area in 2015: a population-level modelling analysis

Background: Infections due to antibiotic-resistant bacteria are threatening modern health care. However, estimating their incidence, complications, and attributable mortality is challenging. We aimed to estimate the burden of infections caused by antibiotic-resistant bacteria of public health concern in countries of the EU and European Economic Area (EEA) in 2015, measured in number of cases, attributable deaths, and disability-adjusted life-years (DALYs). Methods: We estimated the incidence of infections with 16 antibiotic resistance–bacterium combinations from European Antimicrobial Resistance Surveillance Network (EARS-Net) 2015 data that was country-corrected for population coverage. We multiplied the number of bloodstream infections (BSIs) by a conversion factor derived from the European Centre for Disease Prevention and Control point prevalence survey of health-care-associated infections in European acute care hospitals in 2011–12 to estimate the number of non-BSIs. We developed disease outcome models for five types of infection on the basis of systematic reviews of the literature. Findings: From EARS-Net data collected between Jan 1, 2015, and Dec 31, 2015, we estimated 671 689 (95% uncertainty interval [UI] 583 148–763 966) infections with antibiotic-resistant bacteria, of which 63·5% (426 277 of 671 689) were associated with health care. These infections accounted for an estimated 33 110 (28 480–38 430) attributable deaths and 874 541 (768 837–989 068) DALYs. The burden for the EU and EEA was highest in infants (aged <1 year) and people aged 65 years or older, had increased since 2007, and was highest in Italy and Greece. Interpretation: Our results present the health burden of five types of infection with antibiotic-resistant bacteria expressed, for the first time, in DALYs. The estimated burden of infections with antibiotic-resistant bacteria in the EU and EEA is substantial compared with that of other infectious diseases, and has increased since 2007. Our burden estimates provide useful information for public health decision-makers prioritising interventions for infectious diseases

Optimization of lumping schemes for plane square quadratic finite element in elastodynamics

The effectiveness of explicit direct time-integration methods is conditioned by using diagonal mass matrix which entails significant computational savings and storage advantages. In recent years many procedures that produced diagonally lumped mass matrices were developed. For example, the row sum method and diagonal scaling method (HRZ procedure) can be mentioned. In this paper, the dispersive properties of different lumping matrices with variable mass distribution for the plane square 8-node serendipity elements are investigated. The dispersion diagrams for such lumping matrices are derived for various Courant numbers, wavelengths and the directions of wave propagation

Efecto del sistema de labranza y la fertIización nitrogenada sobre el rendimiento de maíz (Zea mays l.) en un haplustol éntIco de la región semIárIda pampeana

El objetivo de este trabajo fue evaluar el efecto de la fertilización nitrogenada sobre el rendimiento de maíz (Zea mays L.) en siembra directa (SD) y en siembra convencional (SC). Para ello se llevó a cabo un ensayo a campo en parcelas dividas en el cual el factor principal era sistema de labranza (SD, SC) y el factor secundario la dosis de fertilización nitrogenada (0, 60, 120 y 180 kg.ha-1 ). La determinación de humedad y de los contenidos de nitrógeno de nitratos en el suelo se realizó en intervalos de 20 cm hasta los 60 cm de profundidad. Los momentos de muestreo fueron en V2 (16/12), V6 (15/1), floración (11/2) y madurez fisiológica (28/4). La fertilización no afectó los rendimientos de maíz en SD cuando las dosis fueron bajas, pero a altas dosis los rendimientos fueron significativamente mayores. En SC los rendimientos variaron significativamente ante menores dosis. Los rendimientos fueron mayores en SD que en SC, comparando los mismos tratamientos de fertilización. Esto se pudo explicar ya que en siembra directa habría mayores contenidos hídricos, mayor mineralización del nitrógeno y menores pérdidas de este elemento por lixiviación

Full Field Computing for Elastic Pulse Dispersion in Inhomogeneous Bars

In the paper, the finite element method and the finite volume method are used in parallel for the simulation of a pulse propagation in periodically layered composites beyond the validity of homogenization methods. The direct numerical integration of a pulse propagation demonstrates dispersion effects and dynamic stress redistribution in physical space on example of a one-dimensional layered bar. Results of numerical simulations are compared with analytical solution constructed specifically for the considered problem. Analytical solution as well as numerical computations show the strong influence of the composition of constituents on the dispersion of a pulse in a heterogeneous bar and the equivalence of results obtained by two numerical methods