Locally equilibrated stress recovery for goal oriented error estimation in the extended finite element method

[EN] Goal oriented error estimation and adaptive procedures are essential for the accurate and efficient evaluation of finite element numerical simulations that involve complex domains. By locally improving the approximation quality, for example, by using the extended finite element method (XFEM), we can solve expensive problems which could result intractable otherwise. Here, we present an error estimation technique for enriched finite element approximations that is based on an equilibrated recovery technique, which considers the stress intensity factor as the quantity of interest. The locally equilibrated superconvergent patch recovery is used to obtain enhanced stress fields for the primal and dual problems defined to evaluate the error estimate.This work was supported by the EPSRC grant EP/G042705/1 "Increased Reliability for Industrially Relevant Automatic Crack Growth Simulation with the eXtended Finite Element Method". Stephane Bordas also thanks partial funding for his time provided by the European Research Council Starting Independent Research Grant (ERC Stg Grant Agreement No. 279578) "RealTCut Towards real time multiscale simulation of cutting in non-linear materials with applications to surgical simulation and computer guided surgery". This work has been carried out within the framework of the research project DPI2010-20542 of the Ministerio de Ciencia e Innovacion (Spain). The financial support of the FPU program (AP2008-01086), the funding from Universitat Politecnica de Valencia and Generalitat Valenciana (PROMETEO/2012/023) are also acknowledged.González Estrada, OA.; Ródenas, J.; Bordas, S.; Nadal, E.; Kerfriden, P.; Fuenmayor Fernández, FJ. (2015). Locally equilibrated stress recovery for goal oriented error estimation in the extended finite element method. Computers and Structures. 152:1-10. https://doi.org/10.1016/j.compstruc.2015.01.015S11015

Vegetative development, fruits yield and optimization of pineapple cv. Pérola with different levels of irrigation

Apesar de ser uma planta com necessidades hídricas relativamente baixas, o abacaxizeiro tem demanda permanente de água, variável ao longo do ciclo e dependente do seu estádio de desenvolvimento. Assim, objetivou-se analisar volumes de irrigação no desenvolvimento vegetativo, no rendimento da fruta e na otimização do abacaxizeiro cv. Pérola. O experimento foi realizado na Universidade Federal de Sergipe, município de São Cristóvão (11°01'S, 37°12'W), no delineamento em blocos ao acaso, com quatro tratamentos (lâminas de água) (100% da evaporação do tanque Classe A (523,7mm ano-1); 75% da evaporação do tanque Classe A (392,8mm ano-1), 50% da evaporação do tanque Classe A (261,8mm ano-1) e 0% da evaporação do tanque Classe A, seis repetições e 12 plantas úteis por parcela. O sistema de irrigação foi por aspersão convencional disposto em linha, com pressão de 20mca e vazão de 1,33m3 h-1. A área foliar (cm2) mínima atingida de 4552,6cm2 foi observada no volume de água de 122,9mm ano-1, enquanto a massa seca das folhas (147,6g) foi constatada com 17mm ano-1. O máximo comprimento da folha D (88,9cm) foi estimado com 532,7 mm ano-1. Já o máximo comprimento do fruto (23cm) foi observado na lâmina de 296,9mm ano-1. A massa do fruto máxima estimado de 1.736g foi constatado na lâmina de 356,4mm ano-1. No contexto, a irrigação contribui de forma positiva no desenvolvimento vegetativo e rendimento da fruta do abacaxizeiro. Ressalta-se remuneração mensal líquida de R 1.161,17ha-1, quando se adota lâmina de irrigação de 356,4mm ano-1. _________________________________________________________________________________________ ABSTRACT: Regardless a relatively low water needs, pineapple fruit has a variable behavior related to water need throughout its biological cycle depending on the development stage. The objective of this work was to analyze irrigation on the vegetative development and fruits yield in pineapple cv. Pérola. The experiment was conducted at the Universidade Federal de Sergipe Experimental Station, at São Cristóvão - SE (11°01'S, 37°12'W), in a randomized block design, with four water level treatments as follow: 100% of Class-A (523.7mm ano-1) evaporation pan; 75% of Class-A (392.8mm ano-1) evaporation pan, 50% of Class-A (261.8mm ano-1) evaporation pan and 0% of Class-A evaporation pan, in six replications and twelve plants per plot. The splinkler watering system of irrigation was installed in a line, with an operating pression of 20 mca and a sprinkler dischrage of 1.33m3h-1. A minimum leaf area of 4552.6cm2 was observed, considering a water level of 122.9mm year-1, while a leaf dry matter was 147.6 g in 17mmyear-1. The maximum leaf length (D) of 88.9cm was estimated considering 532.7mmyear-1. The maximum fruit length of 23cm was observed, considering a water level of 296.9mmyear-1. The maximum estimated fruit weight was 1.736g in a water level of 356.4mm year-1. The irrigation seems to contribute in a positive way to the vegetative development in the pineapple fruit yield. It is important to mention that it could be observed a net profit of R 1,161.17 ha-1, when a water level of 356.4mm ano-1 of irrigation was adopted

High throughput simultaneous assay of atenolol and chlortalidone in combined dose tablets by liquid chromatography and capillary zone electrophoresis

New fast liquid chromatographic and capillary zone electrophoresis methods were developed and validated for simultaneous determination of atenolol and chlortalidone in combined dose tablets. The reversed phase HPLC method was carried out on a CN LiChrosorb® (125 x 4 mm, 5 μm) column. The CZE method was carried out on an uncoated fused-silica capillary of 30 cm x 75 μm i.d. with 25 mmol L-1 sodium tetraborate, pH 9.4. The total analysis time was <6 and <2.5 min for HPLC and CZE methods, respectively. Both methods can be used for stability studies as well.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe