AN EXPLICIT CONSTITUTIVE EQUATION FOR PLANE AND AXISYMMETRIC STEADY FLOWS WITH VISCOELASTIC EFFECTS

Non-Newtonian materials respond differently when submitted to shear or extension. A constitutive equation in which the stress is a function of both the rate of deformation and on the type of the flow is proposed and analyzed theoretically. It combines information obtained in shear, extension and rigid body motion in all regions of complex flow. The analysis has shown how to insert some elastic effects in a constitutive equation that depends only on the present time and position. One advantage of the model is that all the steady rheological functions in simple shear flow and in extensional flow are predicted exactly. Another important property that is included is the split of the extensional viscosity in two parts: one dissipative part that is related to the shear viscosity and an elastic part that is related to the first and second normal stress coefficients in shear. A discussion involving the dimensionless numbers that relate elastic and viscosity effects is also given

AN OBJECTIVE EXPLICIT FORMULATION BASED ON THE OLDROYD-B CONSTITUTIVE EQUATION

In the present paper is shown how to obtain an objective explicit algebraic extra-stress model (AESM) based on differential constitutive equations for viscoelastic flows (Oldroyd B, White-Metzner, Phan-Thien-Tanner, etc). The formulation is developed for three-dimensional time-dependent flows. In a previous work, Mompean, 1998 obtained a non-objective algebraic model. This inconsistency is now removed introducing the relative-rate-ofrotation tensor making the model frame-invariant. A new generalized objective time derivative is also introduced, giving flexibility to the model. Calculations are performed with an Oldroyd B based AESM for a 4:1 contraction flow, showing good agreement with the original constitutive differential model. Several results with particular derivatives are obtained and an analysis guided by a flow type classifier is given. This formulation is able to include a prediction, not present in the Oldroyd B model, the viscometric second normal stress difference, N2

NUMERICAL SIMULATION OF A ELASTO-VISCOPLASTIC FLUID FLOW INSIDE A CAVITY

This article addresses finite element approximations for elasto-viscoplastic flows. Numerical simulations aiming at investigating the role of elasticity for inertialess flows of viscoplastic materials within lid-driven cavity.The mechanical model is made up of the usual governing equations for incompressible fluids coupled with a Oldroyd-B type equation (de Souza Mendes, 2011) modified to incorporate the dependency both of relaxation and retardation time as the viscoplastic viscosity on the strain rate. These parameters depend on the material microstructure, which level is described by an structure parameter . This model is approximated by a multi-field Galerkin least-squares formulation (Behr et al., 1993) in terms of extra-stress tensor, the pressure field and the velocity vector. Results, focused on the determination of yield surface topology, investigate the influence of elastic and viscous governing parameters on the flow pattern

Efeitos do Programa Escola de Postura e Reeducação Postural Global sobre a amplitude de movimento e níveis de dor em pacientes com lombalgia crônica

ResumoObjetivoComparar os efeitos do programa escola de postura (PEP) e reeducação postural global (RPG) sobre níveis de dor e amplitude de movimento em pacientes com lombalgia crônica.MétodoA amostra foi dividida em 3 grupos de 10 sujeitos: grupo submetido ao tratamento através do PEP (idade: 46.30±8.50 anos); grupo submetido ao tratamento através da RPG (idade: 43.60±10.93 anos) e grupo controle (idade: 44.30±10.68 anos). As intervenções foram realizadas em 10 sessões. Para avaliação do quadro álgico foi utilizada a escala subjetiva de dor CR10 de Borg. Para a análise da amplitude de movimento empregou‐se o protocolo de goniometria LABIFIE para os movimentos de extensão coxofemoral (ECF) e flexão da coluna lombar (FCL).ResultadosO teste de Wilcoxon mostrou uma redução nos escores dos níveis de dor nos grupos PEP e RPG (p<0.0001) do pré para o pós‐tratamento. As comparações intergrupos, através do teste de Kruskal‐Wallis, apresentaram diminuição dos níveis de dor para o PEP (p<0.0001) e o RPG (p<0.0001) quando comparados ao CG no pós‐tratamento. A ANOVA com medidas repetidas revelou um aumento na amplitude do movimento para o PEP (ECF: p=0.006; FCL: p=0.002) e RPG (ECF: p=0.034; FCL: p=0.011) do pré para o pós‐tratamento. As comparações intergrupos apresentaram maiores amplitudes de movimento para o PEP (ECF: p=0.006; FCL: p=0.018) e RPG (EQ: p=0.019; FCL: p=0.020) quando comparados ao CG no pós‐tratamento. Não houve diferenças significativas entre o PEP e RPG.ConclusãoOs tratamentos PEP e RPG se mostraram eficientes para redução da lombalgia crônica.AbstractObjectiveTo compare the effects of school‐based exercise program of posture (SPP) and global postural reeducation (GPR) on pain levels and range of motion in patients with chronic low back pain.MethodThe sample was divided into three groups of 10 subjects: group treated by SPP (age: 46.30±8.50 years) group subjected to treatment by GPR (age: 43.60±10.93 years) and control group (age: 44.30±10.68 years). The interventions were performed in 10 sessions. For assessment of pain was used pain subjective scale CR10‐Borg. For the analysis of range of motion, we used the protocol to goniometry LABIFIE in the movements of hip extension (HE) and flexion of the lumbar spine (FLS).ResultsThe Wilcoxon test showed a reduction in levels of pain scores in groups SPP and GPR (p<0.0001) of pre to post‐treatment. Comparisons between groups by the Kruskal‐Wallis test showed decreased levels of pain for SPP (p<0.0001) and GPR (p<0.0001) when compared to CG post‐treatment. Repeated measures ANOVA revealed an increase in range of motion for the SPP (HE: p=0.006; FLS: p=0.002) and GPR (HE: p=0.034; FLS: p=0.011) of pre to post‐treatment. Comparisons between groups showed greater range of motion for the SPP (HE: p=0.006; FLS: p=0.018) and GPR (HE: p=0.019; FLS: p=0.020) when compared to CG post‐treatment. There were no significant differences between the SPP and GPR.ConclusionsSPP and GPR treatments were effective for reducing chronic low back pain

MULTI-FIELD STABILIZED FINITE ELEMENT APPROXIMATIONS FOR OLDROYD-B FLUID FLOWS

This work concerns with numerical simulations of creeping and inertial flows of viscoelastic fluids. The mechanical model consists of mass and momentum balance equations, coupled with the Oldroyd-B fluid. The model is approximated by a multi-field Galerkin least-squares (GLS) methodology in terms of extra-stress, velocity and pressure. The GLS method, introduced by Hughes et al. (1986) in the context of the Stokes problem for Newtonian fluidflows, allows the use of combinations of equal-order finite element interpolations and remains stable even for elastic- and inertiadominated fluid flows. Some steady simulations of Oldroyd-B fluids, flowing over a slot, are herein carried out. The influence of inertia and fluid viscoelasticity is taken into account ranging the Reynolds and Weissenberg numbers for relevant values of this flow. The results are in accordance to the viscoelastic literature and reassure the fine stability features of the GLS formulation

Efficiency of biological control for fall armyworm resistant to the protein Cry1F.

O entendimento de relações ecológicas e toxicológicas envolvendo culturas geneticamente modificadas (GM) e agentes de controle biológico é de grande importância para discussões relativas à compatibilidade de culturas GM com estratégias de manejo integrado e manejo de resistência de pragas. Este trabalho avaliou o comportamento de busca e a capacidade predatória de Orius insidiosus (Say) (Hemiptera: Anthocoridae) e Doru luteipes (Scudder) (Dermaptera: Forficulidae) sobre ovos e lagartas de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistente ou não à proteína Cry1F expressa em milho Bt. Para determinar o tempo de busca foi utilizado um cronômetro que foi disparado até a captura da primeira presa; a capacidade de predação foi avaliada através da contagem das presas remanescentes 24 h após infestação. Também foram avaliadas as injúrias de S. frugiperda em milho transgênico e milho convencional na presença ou ausência dos predadores. Os predadores não foram capazes de distinguir entre presas (ovos ou lagartas) resistentes e suscetíveis, considerando os comportamentos predatórios avaliados. Não houve diferença no tempo de busca e capacidade predatória sobre ovos e lagartas de S. frugiperda resistente ou suscetível entre os predadores. Na presença dos predadores, as notas de injúria de S. frugiperda resistente nas plantas de milho Bt foram menores. Conclui-se que O. insidiosus e D. luteipes não percebem a presença da proteína Cry1F na presa S. frugiperda, o que pode contribuir para o uso integrado de milho GM e controle biológico em programas de manejo integrado e manejo de resistência de pragas.Ahead of print

Efeito da irradiação gama sobre fatores antinutricionais em feijões comerciais (Phaseolus vulgaris l.) do grupo carioca.

Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos da irradiação sobre os fatores antinutricionais (taninos e fitatos) de feijões comerciais (Phaseolus vulgaris L.) grupo carioca, tendo em vista que, a presença destes antinutrientes tem-se tornado nutricionalmente indesejável, pelo fato de promover à baixa biodisponibilidade de macromoléculas, como proteínas, carboidratos, aminoácidos, vitaminas e minerais, pela formação de complexos.CONAFE