Análise da influência de modelos dinâmicos de caminhar humano na resposta de aceleração em pisos mistos de aço e concreto

Modern architecture has required the use of structures without partitions, with the possibility of using lighter sealing elements that are easy to adapt to new layouts. In addition, the speed of construction is an important factor in choosing the structural conception, especially for spaces with commercial purposes. In this scenario, composite steel and concrete structures stand out. However, these aspects reduce the global stiffness of the structure, leading to a decrease in its fundamental frequency, which approach the most common frequencies of walking activities, resulting in problems related to excessive vibration. Therefore, in order to avoid excessive vibration problems, it is essential to verify the structure considering the most commons dynamic loads, either through simplified methods, or through refined numerical methods, such as the Finite Element Method. In the light of the foregoing, the present paper analysed different dynamic loading models that represent human walking activities, applying them in composite steel and concrete floors that were previously experimentally tested, obtained in the technical literature, which were modelled numerically in the software Ansys. For the execution of the work, 10 dynamic loading models and 4 floors were selected, 2 classified as low fundamental frequency and 2 as high. In total, 130 simulations were performed, obtaining 220 acceleration histories over time. Based on the historical data, it was determined which dynamic model best represent human walking for different situations. Issues such as measurement position (on the walk path or in nearby regions), integration pace in transient analyses, post-processing of acceleration results, removal of peaks considered as outliers, among others, were evaluated. All comparisons were made in terms of peak acceleration and rms acceleration, where the quality of each model was verified for these criteria. It was concluded that the biodynamic models have better quality than the other models in peak acceleration analysis. However, for analyses related to rms acceleration, the heel impact model and the single step model stood out. In addition, criteria were defined for the removal of outliers, based on the results obtained in this paper. Regarding the simplified methods, it was observed that the Brazilian standard method was not accurate in many simulations, with better results only for rigid structures. As for the American and European standards method, these provided better results on low fundamental frequency floors, as for the aforementioned frequency, however, for analyses related to acceleration, these methods led to values below those of reference.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESA arquitetura moderna tem requisitado o uso de estruturas sem partições, com a possibilidade do uso de elementos de vedação mais leves e de fácil adaptação a novos layouts. Além disso, a velocidade de construção é um fator importante na escolha da solução estrutural adotada, principalmente para ambientes com finalidade comercial. Neste cenário destacam-se as estruturas mistas de aço e concreto. No entanto, estes aspectos reduzem a rigidez global da estrutura, levando a um decréscimo da sua frequência fundamental, que se aproxima das frequências mais comuns das atividades de caminhar, acarretando em problemas relacionados a vibração excessiva. Portanto, a fim de evitar estes tipos de problemas é imprescindível a verificação da estrutura considerando estas situações, seja através de métodos simplificados, seja através de métodos numéricos refinados, como o Método dos Elementos Finitos. Em vista dos fatos mencionados, o presente trabalho analisou diferentes modelos de carregamento dinâmico que representem atividades de caminhar humano, aplicando-os em pisos mistos de aço e concreto que foram previamente ensaiados experimentalmente, obtidos na literatura técnica, os quais foram modelados numericamente no software Ansys. Para a execução do trabalho foram selecionados 10 modelos de carregamento dinâmico e 4 pisos, sendo 2 classificados como de baixa frequência fundamental e 2 de alta. Ao total foram executadas 130 simulações, obtendo 220 históricos de aceleração ao longo do tempo. Com base nos históricos foi determinado quais modelos dinâmicos melhor representam o caminhar humano para diferentes situações. Foram avaliadas questões como posição da medição (no trajeto da caminhada ou em regiões vizinhas), intervalo de integração nas análises transientes, pósprocessamento dos resultados de aceleração, remoção de picos considerados fora de série (outliers), entre outras. Todas as comparações foram realizadas em termos de aceleração de pico e rms, onde foi verificada a qualidade de cada modelo para estes critérios. Concluiu-se que os modelos biodinâmicos apresentam melhor qualidade que os demais modelos em análises de aceleração de pico. No entanto, para análises relativas à aceleração rms, o modelo de impacto do calcanhar e o modelo de passo único destacaram-se. Além disso, foram definidos critérios para a remoção dos outliers, com base nos resultados obtidos neste trabalho. Com relação aos métodos simplificados, observou-se que o método da norma brasileira não foi preciso em muitas simulações, com melhores resultados apenas para pisos rígidos. Quanto ao método das normas americana e europeia, estes proporcionaram melhores resultados em pisos de baixa frequência fundamental, quanto a citada frequência, porém, para análises relativas à aceleração, estes métodos levaram a valores abaixo aos de referência.São Cristóvão, S

Numerical evaluation of dynamic load models of humans walking on building floors

ABSTRACT Composite steel and concrete floors are often susceptible to excessive vibrations caused by human activities because of their slender structural elements. To achieve a precise evaluation, it is necessary to incorporate the effects of dynamic loads in the computational model; however, it is difficult to predict this type of load. This study aims to analyze a set of human dynamic load models applied to four composite steel and concrete floors and verify which model can simulate the real load effects by comparing the numerical results obtained in this research with the experimental results obtained in other studies. It was possible to determine the dynamic model that yielded peak and root mean square accelerations closer to the experimental values for different analysis situations

Açaí (Euterpe oleracea) and Bacaba (Oenocarpus bacaba) as Functional Food

This chapter reviews two oleaginous fruits that are widely consumed by people in the Amazon region: Bacaba (Oenocarpus bacaba) and Açaí (Euterpe oleracea). Besides their food and the folk medicinal uses, studies suggest that substances present in both berries have antioxidative effects, antimicrobial, and therapeutic properties such as hypocholesterolemic and neuroprotection effects. These therapeutic effects are related to phenolic compounds, anthocyanins, and fatty acids, which can prevent serious problems such as coronary heart disease, hypertension, and depression. The use of supercritical fluid technology is described as a technique to obtain the best extracts of bacaba and açaí, as well as their valuable constituents. Indubitably, this technology is a great tool for human health and all with the advantage of presenting nontoxic solvents such as carbon dioxide or water. Açaí and bacaba fruits represent not only food but also a source of compounds that can work in both prevention and treatment of diseases

UTILIZAÇÃO DE LODO DE CURTUME EM COMPLEMENTAÇÃO AO SUBSTRATO COMERCIAL NA PRODUÇÃO DE MUDAS DE PIMENTA BIQUINHO

A utilização de resíduos industriais, como o lodo de curtume, em substratos para produção de mudas é uma alternativa para redução de custos de produção, e para destinação dos resíduos industriais. O cultivo de pimentas tem ganhado espaço no mercado brasileiro favorecendo principalmente a agricultura familiar, onde um dos desafios é diminuir o custo de produção. O objetivo do trabalho foi avaliar o efeito de diferentes concentrações de lodo de curtume bovino adicionado ao substrato comercial na germinação, desenvolvimento e qualidade de mudas de pimenta biquinho. O experimento foi conduzido em delineamento de blocos casualizados com 7 tratamentos, sendo dois substratos comerciais: Provaso® (TP) e Bioplant® (TL0); e cinco diferentes proporções de lodo desidratado (10, 30, 50, 70 e 90%) misturados ao substrato Bioplant®. Avaliou-se nesse experimento o percentual de germinação, características de desenvolvimento e Índice de Qualidade de mudas de Dickson (IQD). O potencial germinativo foi maior para os tratamentos com adição de lodo de curtume ao substrato comercial Bioplant®. Os melhores resultados para as características de desenvolvimento das mudas ocorreram com a adição de lodo desidratado ao substrato Bioplant® nos intervalos de 30 a 70% de lodo no substrato. O índice de qualidade de mudas foi maior para a mistura de 30% de lodo de curtume desidratado com Bioplant®

Carbon Dioxide Use in High-Pressure Extraction Processes

This chapter describes the use of carbon dioxide at high pressures as an alternative for the extraction of bioactive compounds in a more sustainable way, addressing some of its physicochemical properties, such as pressure, temperature, density, solvation, selectivity, and its interaction with the solute when modified by other solvents such as ethanol and water. This extraction process is considered chemically “green,” when compared to conventional extraction processes using toxic organic solvents

Potential of Medicinal Use of Essential Oils from Aromatic Plants

The use of medicinal plants rich in essential oils can represent a viable source for the control of some diseases, being able to constitute a possible therapeutic alternative due to its effectiveness. Essential oils are natural volatile fractions extracted from aromatic plants and formed by classes of substances such as esters of fatty acids, mono and sesquiterpenes, phenylpropanoids, aldehyde alcohols and, in some cases, aliphatic hydrocarbons, among others. Essential oils have been used by mankind for medicinal purposes for several centuries, with reports coming from Ancient Egypt. In this sense, the present work aims to approach the biological activities of essential oils such as antioxidant, anticancer, antiprotozoal, antifungal, antibacterial and anti-inflammatory activities of different plant matrices rich in essential oils

Antioxidant and Biological Activity of <em>Cissus sicyoides</em> and <em>Rosmarinus officinalis</em> Extracts

This chapter will describe the antioxidant and biological activity of Cissus sicyoides and Rosmarinus officinalis leaf extracts, which represent an important natural source of antioxidants. These plants contain several bioactive compounds with high antioxidant activity, such as phenolic compounds, which are compounds that prevent or delay oxidative stress, acting as free radical scavengers (FRSs), and thus reduce the onset of cardiovascular disease, cancer, diabetes, epilepsy, stroke, among other diseases. The supercritical fluid extraction (SFE) has been studied to obtain antioxidant compounds from natural sources, without the drawbacks associated with conventional extraction processes, such as the use of organic solvents, which present toxicity and contaminate the extracts, is proposed

Limb girdle muscular dystrophy type 2G with myopathic-neurogenic motor unit potentials and a novel muscle image pattern

Abstract\ud \ud Background\ud Limb girdle muscular dystrophy type 2G (LGMD2G) is a subtype of autosomal recessive muscular dystrophy caused by mutations in the telethonin gene. There are few LGMD2G patients worldwide reported, and this is the first description associated with early tibialis anterior sparing on muscle image and myopathic-neurogenic motor unit potentials.\ud \ud \ud Case presentation\ud Here we report a 31 years old caucasian male patient with progressive gait disturbance, and severe lower limb proximal weakness since the age of 20 years, associated with subtle facial muscle weakness. Computed tomography demonstrated soleus, medial gastrocnemius, and diffuse thigh muscles involvement with tibialis anterior sparing. Electromyography disclosed both neurogenic and myopathic motor unit potentials. Muscle biopsy demonstrated large groups of atrophic and hypertrophic fibers, frequent fibers with intracytoplasmic rimmed vacuoles full of autophagic membrane and sarcoplasmic debris, and a total deficiency of telethonin. Molecular investigation identified the common homozygous c.157C > T in the TCAP gene.\ud \ud \ud Conclusion\ud This report expands the phenotypic variability of telethoninopathy/ LGMD2G, including: 1) mixed neurogenic and myopathic motor unit potentials, 2) facial weakness, and 3) tibialis anterior sparing. Appropriate diagnosis in these cases is important for genetic counseling and prognosis.We wish to thank the patient for participation in this study. We acknowledge\ud Cleides Campos de Oliveira, Leticia Nogueira and Simone Ferreira do\ud Nascimento for technical assistance. MV, LUY and CFA are supported by\ud FAPESP-CEPID, and INCT-CNPq, Capes- COFECUB