Multiextrapolação de Richrdson completa para o método de volumes finitos

Orientador : Prof. Dr. Carlos H. MarchiTese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Mecânica. Defesa : Curitiba, 03/10/2017Inclui referências : p. 97-100Resumo: A motivação principal deste trabalho consiste na redução do erro de discretização por meio do emprego da Extrapolação Richardson Completa (CRE) em problemas resolvidos pelo método de Volumes Finitos. CRE é a Extrapolação de Richardson empregada em todo o campo de soluções. É analisado também o efeito dessas extrapolações em variáveis secundárias de problemas de CFD. CRE já foi comprovada na literatura que é eficiente para problemas de Diferenças Finitas. Foram resolvidas as equações de Poisson, advecção-difusão, o problema da cavidade com tampa móvel modelado pelas equações de Navier Stokes, ambos problemas de escoamentos incompressíveis. Foram utilizadas funções de interpolação de 1ª, 2ª, 3ª e 4ª ordens de acurácia para as discretizações e de 10 a 20 malhas de 2 a 1048576 nós. Nas soluções desses problemas de CFD foram feitas análises da redução do erro de discretização com MER e CRE. Para ampliar a avaliação das variáveis de interesse, através da expansão de MER em campos de soluções, é analisada a redução do erro numérico em variáveis secundárias como temperatura média, inclinação nos contornos, temperatura no ponto médio, fluxo de massa e força de arrasto viscoso. Para a ordem de acurácia de variáveis secundárias, a partir de soluções nodais, são mostrados diversos experimentos numéricos e um teorema que generaliza os padrões observados. Com a utilização das faces das malhas 1D e das quinas das malhas 2D se tornou possível o emprego de CRE em Volumes Finitos. O desempenho dessa técnica nos problemas estudados se mostrou equivalente ao encontrado na literatura para Diferenças Finitas. Constatou-se que CRE é um método eficaz para a redução do erro numérico também para problemas de Volumes Finitos. No desempenho do erro de variáveis secundárias, CRE contribui para a redução do erro, porém, o emprego de MER diretamente nas variáveis secundárias pode ser mais eficiente. Palavras-Chave: Multiextrapolações de Richardson. Erro de discretização. Variáveis secundárias.Abstract: The scope of this research is to reduce the discretization error through the use of Completed Richardson Extrapolation (CRE) in problems solved by the Finite Volumes method. CRE is the Richardson Extrapolation employed across the entire field of solutions. The effect of these extrapolations on secondary variables of CFD problems is also analyzed. CRE has already been proven in the literature that is efficient for problems of Finite Differences. The Poisson equations, advection-diffusion, the cavity problem with movable cover modeled by the Navier Stokes equations, both incompressible flow problems, were solved. First, second, third and fourth interpolation functions were used for the discretizations and from 10 to 20 meshes from 2 to 1048576 nodes. In the solutions of these CFD problems analyzes of the reduction of the discretization error with MER and CRE were made. In order to extend the evaluation of the variables of interest, through the expansion of MER in solution fields, the numerical error reduction in secondary variables such as average temperature, contour slope, temperature at the midpoint, mass flow and viscous drag. For the order of accuracy of secondary variables, from nodal solutions, we show several numerical experiments and a theorem that generalizes the observed patterns. With the use of the faces of the 1D meshes and the 2D meshes, it became possible to use CRE in Finite Volumes. The performance of this technique in the studied problems was shown to be equivalent to that found in the literature for Finite Differences. It has been found that CRE is an effective method for the reduction of numerical error also for finite volume problems. In the performance of the error of secondary variables, CRE contributes to the reduction of the error, however, the use of MER directly in the secondary variables can be more efficient. Keywords: Repeated Richardson Extrapolations. Discretization error. Secondary variables

Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants

Background Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories. Methods We used data from 1990 to 2019 on people aged 30–79 years from population-representative studies with measurement of blood pressure and data on blood pressure treatment. We defined hypertension as having systolic blood pressure 140 mm Hg or greater, diastolic blood pressure 90 mm Hg or greater, or taking medication for hypertension. We applied a Bayesian hierarchical model to estimate the prevalence of hypertension and the proportion of people with hypertension who had a previous diagnosis (detection), who were taking medication for hypertension (treatment), and whose hypertension was controlled to below 140/90 mm Hg (control). The model allowed for trends over time to be non-linear and to vary by age. Findings The number of people aged 30–79 years with hypertension doubled from 1990 to 2019, from 331 (95% credible interval 306–359) million women and 317 (292–344) million men in 1990 to 626 (584–668) million women and 652 (604–698) million men in 2019, despite stable global age-standardised prevalence. In 2019, age-standardised hypertension prevalence was lowest in Canada and Peru for both men and women; in Taiwan, South Korea, Japan, and some countries in western Europe including Switzerland, Spain, and the UK for women; and in several low-income and middle-income countries such as Eritrea, Bangladesh, Ethiopia, and Solomon Islands for men. Hypertension prevalence surpassed 50% for women in two countries and men in nine countries, in central and eastern Europe, central Asia, Oceania, and Latin America. Globally, 59% (55–62) of women and 49% (46–52) of men with hypertension reported a previous diagnosis of hypertension in 2019, and 47% (43–51) of women and 38% (35–41) of men were treated. Control rates among people with hypertension in 2019 were 23% (20–27) for women and 18% (16–21) for men. In 2019, treatment and control rates were highest in South Korea, Canada, and Iceland (treatment >70%; control >50%), followed by the USA, Costa Rica, Germany, Portugal, and Taiwan. Treatment rates were less than 25% for women and less than 20% for men in Nepal, Indonesia, and some countries in sub-Saharan Africa and Oceania. Control rates were below 10% for women and men in these countries and for men in some countries in north Africa, central and south Asia, and eastern Europe. Treatment and control rates have improved in most countries since 1990, but we found little change in most countries in sub-Saharan Africa and Oceania. Improvements were largest in high-income countries, central Europe, and some upper-middle-income and recently high-income countries including Costa Rica, Taiwan, Kazakhstan, South Africa, Brazil, Chile, Turkey, and Iran. Interpretation Improvements in the detection, treatment, and control of hypertension have varied substantially across countries, with some middle-income countries now outperforming most high-income nations. The dual approach of reducing hypertension prevalence through primary prevention and enhancing its treatment and control is achievable not only in high-income countries but also in low-income and middle-income settings

Multiextrapolação de Richrdson completa para o método de volumes finitos

Orientador : Prof. Dr. Carlos H. MarchiTese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Mecânica. Defesa : Curitiba, 03/10/2017Inclui referências : p. 97-100Resumo: A motivação principal deste trabalho consiste na redução do erro de discretização por meio do emprego da Extrapolação Richardson Completa (CRE) em problemas resolvidos pelo método de Volumes Finitos. CRE é a Extrapolação de Richardson empregada em todo o campo de soluções. É analisado também o efeito dessas extrapolações em variáveis secundárias de problemas de CFD. CRE já foi comprovada na literatura que é eficiente para problemas de Diferenças Finitas. Foram resolvidas as equações de Poisson, advecção-difusão, o problema da cavidade com tampa móvel modelado pelas equações de Navier Stokes, ambos problemas de escoamentos incompressíveis. Foram utilizadas funções de interpolação de 1ª, 2ª, 3ª e 4ª ordens de acurácia para as discretizações e de 10 a 20 malhas de 2 a 1048576 nós. Nas soluções desses problemas de CFD foram feitas análises da redução do erro de discretização com MER e CRE. Para ampliar a avaliação das variáveis de interesse, através da expansão de MER em campos de soluções, é analisada a redução do erro numérico em variáveis secundárias como temperatura média, inclinação nos contornos, temperatura no ponto médio, fluxo de massa e força de arrasto viscoso. Para a ordem de acurácia de variáveis secundárias, a partir de soluções nodais, são mostrados diversos experimentos numéricos e um teorema que generaliza os padrões observados. Com a utilização das faces das malhas 1D e das quinas das malhas 2D se tornou possível o emprego de CRE em Volumes Finitos. O desempenho dessa técnica nos problemas estudados se mostrou equivalente ao encontrado na literatura para Diferenças Finitas. Constatou-se que CRE é um método eficaz para a redução do erro numérico também para problemas de Volumes Finitos. No desempenho do erro de variáveis secundárias, CRE contribui para a redução do erro, porém, o emprego de MER diretamente nas variáveis secundárias pode ser mais eficiente. Palavras-Chave: Multiextrapolações de Richardson. Erro de discretização. Variáveis secundárias.Abstract: The scope of this research is to reduce the discretization error through the use of Completed Richardson Extrapolation (CRE) in problems solved by the Finite Volumes method. CRE is the Richardson Extrapolation employed across the entire field of solutions. The effect of these extrapolations on secondary variables of CFD problems is also analyzed. CRE has already been proven in the literature that is efficient for problems of Finite Differences. The Poisson equations, advection-diffusion, the cavity problem with movable cover modeled by the Navier Stokes equations, both incompressible flow problems, were solved. First, second, third and fourth interpolation functions were used for the discretizations and from 10 to 20 meshes from 2 to 1048576 nodes. In the solutions of these CFD problems analyzes of the reduction of the discretization error with MER and CRE were made. In order to extend the evaluation of the variables of interest, through the expansion of MER in solution fields, the numerical error reduction in secondary variables such as average temperature, contour slope, temperature at the midpoint, mass flow and viscous drag. For the order of accuracy of secondary variables, from nodal solutions, we show several numerical experiments and a theorem that generalizes the observed patterns. With the use of the faces of the 1D meshes and the 2D meshes, it became possible to use CRE in Finite Volumes. The performance of this technique in the studied problems was shown to be equivalent to that found in the literature for Finite Differences. It has been found that CRE is an effective method for the reduction of numerical error also for finite volume problems. In the performance of the error of secondary variables, CRE contributes to the reduction of the error, however, the use of MER directly in the secondary variables can be more efficient. Keywords: Repeated Richardson Extrapolations. Discretization error. Secondary variables

Núcleos de Ensino da Unesp: artigos 2008

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Núcleos de Ensino da Unesp: artigos 2007

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

ISARIC-COVID-19 dataset: A Prospective, Standardized, Global Dataset of Patients Hospitalized with COVID-19

The International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) COVID-19 dataset is one of the largest international databases of prospectively collected clinical data on people hospitalized with COVID-19. This dataset was compiled during the COVID-19 pandemic by a network of hospitals that collect data using the ISARIC-World Health Organization Clinical Characterization Protocol and data tools. The database includes data from more than 705,000 patients, collected in more than 60 countries and 1,500 centres worldwide. Patient data are available from acute hospital admissions with COVID-19 and outpatient follow-ups. The data include signs and symptoms, pre-existing comorbidities, vital signs, chronic and acute treatments, complications, dates of hospitalization and discharge, mortality, viral strains, vaccination status, and other data. Here, we present the dataset characteristics, explain its architecture and how to gain access, and provide tools to facilitate its use