Avaliação da influência dos revestimentos utilizados como proteção em aço de ultra-alta resistência no processo de estampagem a quente

É crescente a necessidade de aumento da eficiência energética e redução da emissão de gases poluentes no setor automotivo. Neste contexto surgem os aços avançados de alta resistência (AHSS), a partir de um esforço dos maiores fabricantes de aços no mundo. No entanto a conformação a frio desses materiais é complexa, sendo necessário o desenvolvimento do processo a quente, a partir disso ocorre a consolidação destes aços no mercado e passam a ocorrer pesquisas no sentido de entender a influência da adição de camadas de revestimentos protetoreras na matériaprima. Os revestimentos à base de Zn ou Al-Si são os mais comumente utilizados atualmente. Este estudo tem como objetivo analisar a influência do revestimento alumínio-silício depositado no aço 22MnB5, após o processo de estampagem a quente em matriz refrigerada. Diversas características foram avaliadas, como: resistência a corrosão, integridade superficial, redução de massa, além de análise através de microscópio óptico e eletrônico de varredura do substrato e do revestimento. As peças revestidas obtiveram melhor resultado de rugosidade, apresentando cerca de 30% inferiores. As amostras revestidas sofreram menor impacto corrosivo durante as avaliações dos testes de corrosão cíclica, porém o potencial de passivação das amostras não revestidas foi menor. Os valores de microdureza foram cerca de 8% superiores para o material aluminizado, entretanto por se tratar de uma estampagem em matriz refrigerada ambos materiais obtiveram microestrutura de maioria martensítica. As avaliação de força de estampagem e dissipação térmica nas matrizes mostrou pouca relevância da adição do revestimento, obtendo valores similares em ambos materiais.There is a growing need for energy efficiency and reducing the emission of polluting gases in automobiles. In this context are advanced high strength steels (AHSS), an effort by the largest steel manufacturers in the world. However, from a deformability, these materials are complex, being necessary the development of the process from hot materials, being necessary the development of the process to occur steels in the market and to pass for an influence of the addition of hot layers of protective coatings. in matter. -cousin. The main coatings are those based on Zn or Al-Si. This study aims to analyze the influence of the aluminized coating deposited on 22MnB5 steel, after the hot stamping process in the chilled die. Different coating analysis tools such as various analysis resistances, surface, miscellaneous, as well as appearance change techniques and appearance and thickness change characteristics. The fitted pieces had the best carpet result, showing about 30% lower. The estimates avoided, however, the lesser impact of passivation of unprotected cells was the impact of passivation of smaller ones. The microhardness values were about 8% higher than the aluminized material, however to deal with a cold die stamping both materials obtained microstructure of martensitic majority. Both materials evaluate the stamping force and evaluate the dies evaluation values, reflecting similar values in both materials

Avaliação ambiental de manguezais adjacentes aos campos petrolíferos de Macau e Serra (RN), como subsídio às medidas mitigadoras ao processo erosivo

Among the various effects caused by the climate change and human intervention, the mangrove ecosystem changes through of the years has been worth mentioning, which hasn t known which are the pros and cons for the adjacent coastal and estuarine environments yet. It happens due to the present dynamism in these areas, besides of the difficult understanding of the processes associated with evolution. This study aimed to environmentally evaluate adjacent mangroves from the Macau and Serra oil fields, located on Rio Grande do Norte northern coast, to support the mitigating actions related to the containment of the erosive process, as well as, according to the principles of the Clean Development Mechanism (CDM), to assess the amount of atmospheric carbon sequestered by the studied ecosystem. An inventory was conducted through mangrouve mapping which has supplied this research, especially regarding to the structural characterization of mangrove areas. To understand the local mangrove behavior in a greater level detail, techniques of remote sensing, GIS and GPS were used to make an analogy between the current and past states of the mangrove studied, allowing to make anticipated projections for the future impacts or changes in that region. This study combined data from multispectral LANDSAT 5 TM, Landsat 7 ETM+ with radar microwave data from SAR RADARSAT-1, which increased the interpretation capacity of the data from optical sensor systems. The interpretations have been supported by the data field, representing a better and innovative methodology for the environmental and taxonomic characterization of mangrove forests considered. The results reveal that mangroves of the Ponta do Tubarão Sustainable Development Reserve are biologically representative areas and providing a variety of benefits, especially for local communities, constituting the priority sites for actions development aimed at conservation. They also have been showing the necessity to make mitigating measures in order to recover degraded areas through reforestation or creating new areas of mangrove, as currently 7.1% of the mangrove forests studied are dead or in an advanced state of decomposition. The amount of atmospheric carbon sequestered proved very significant when analyzed for the whole area, which is able to sequester atmospheric 4,294,458 Ton CO2 per yearDentre os diversos efeitos provocados pelas mudanças climáticas e pela intervenção humana, as alterações no ecossistema manguezal vêm merecendo destaque, cujas implicações para os ambientes estuarinos e costeiros adjacentes ainda estão distantes de serem conhecidas. Isto ocorre devido ao dinamismo presente nessas áreas, assim como a difícil compreensão dos processos associados à evolução das mesmas. O presente estudo teve como principal objetivo avaliar ambientalmente manguezais adjacentes aos campos petrolíferos de Macau e Serra, localizados no litoral setentrional do Rio Grande do Norte, como subsídio às medidas mitigadoras ao processo erosivo, além de, dentro dos princípios do chamado Mecanismo de Desenvolvimento Limpo (MDL), avaliar a quantidade de carbono atmosférico sequestrado para o ecossistema estudado. Através de mapeamento do manguezal, foi realizado um inventário, o que forneceu subsídios para o delineamento desta pesquisa, principalmente, no que diz respeito à caracterização estrutural da área de manguezal. Para entender o comportamento do manguezal em questão em um nível maior de detalhe, buscaram-se explicações em unidades espaciais maiores. Técnicas de Sensoriamento Remoto, SIG e GPS forneceram informações de comparação entre os estados atual e passado do manguezal, possibilitando projeções antecipadas para os futuros impactos ou alterações desta região. Este trabalho combinou dados multiespectrais do LANDSAT 5 TM, LANDSAT 7 ETM+ com dados de microondas de radar do tipo SAR do RADARSAT-1, ampliando a capacidade de interpretação dos dados de sistemas de sensores óticos. As interpretações foram apoiadas com dados de campo, objetivando uma melhor e inovadora metodologia para a caracterização ambiental e taxonômica das florestas de mangue em questão. Os resultados encontrados revelam que os manguezais da Reserva de Desenvolvimento Sustentável Estadual Ponta do Tubarão são áreas representativas biologicamente e que fornecem uma variedade de benefícios, principalmente para as comunidades locais, constituindo-se de sítios prioritários para o desenvolvimento de ações com vistas a sua conservação. Revelam também a necessidade de se tomar medidas mitigadoras no sentido de recuperar as áreas degradadas ou através do reflorestamento se criar novas áreas de manguezal, pois atualmente 7,1% das florestas de mangue estudadas encontram-se mortas ou em estado de decomposição bem avançado. A quantidade de carbono atmosférico sequestrado se mostrou bem significativa quando analisado para toda a área em questão, sendo esta, capaz de sequestrar 4.294.458 Ton CO2 atmosférico/an

Most published meta-regression analyses based on aggregate data suffer from methodological pitfalls: a meta-epidemiological study.

BACKGROUND Due to clinical and methodological diversity, clinical studies included in meta-analyses often differ in ways that lead to differences in treatment effects across studies. Meta-regression analysis is generally recommended to explore associations between study-level characteristics and treatment effect, however, three key pitfalls of meta-regression may lead to invalid conclusions. Our aims were to determine the frequency of these three pitfalls of meta-regression analyses, examine characteristics associated with the occurrence of these pitfalls, and explore changes between 2002 and 2012. METHODS A meta-epidemiological study of studies including aggregate data meta-regression analysis in the years 2002 and 2012. We assessed the prevalence of meta-regression analyses with at least 1 of 3 pitfalls: ecological fallacy, overfitting, and inappropriate methods to regress treatment effects against the risk of the analysed outcome. We used logistic regression to investigate study characteristics associated with pitfalls and examined differences between 2002 and 2012. RESULTS Our search yielded 580 studies with meta-analyses, of which 81 included meta-regression analyses with aggregated data. 57 meta-regression analyses were found to contain at least one pitfall (70%): 53 were susceptible to ecological fallacy (65%), 14 had a risk of overfitting (17%), and 5 inappropriately regressed treatment effects against the risk of the analysed outcome (6%). We found no difference in the prevalence of meta-regression analyses with methodological pitfalls between 2002 and 2012, nor any study-level characteristic that was clearly associated with the occurrence of any of the pitfalls. CONCLUSION The majority of meta-regression analyses based on aggregate data contain methodological pitfalls that may result in misleading findings

Viscosupplementation for knee osteoarthritis: systematic review and meta-analysis

Objective: To evaluate the effectiveness and safety of viscosupplementation for pain and function in patients with knee osteoarthritis. Design: Systematic review and meta-analysis of randomised trials. Data sources Searches were conducted of Medline, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception to 11 September 2021. Unpublished trials were identified from the grey literature and trial registries. Eligibility criteria for study selection: Randomised trials comparing viscosupplementation with placebo or no intervention for knee osteoarthritis treatment. Main outcome measures: The prespecified primary outcome was pain intensity. Secondary outcomes were function and serious adverse events. Pain and function were analysed as standardised mean differences (SMDs). The prespecified minimal clinically important between group difference was −0.37 SMD. Serious adverse events were analysed as relative risks. Methods: Two reviewers independently extracted relevant data and assessed the risk of bias of trials using the Cochrane risk of bias tool. The predefined main analysis was based only on large, placebo controlled trials with ≥100 participants per group. Summary results were obtained through a random effects meta-analysis model. Cumulative meta-analysis and trial sequential analysis under a random effects model were also performed. Results: 169 trials provided data on 21 163 randomised participants. Evidence of small study effects and publication biases was observed for pain and function (Egger’s tests with P<0.001 and asymmetric funnel plots). Twenty four large, placebo controlled trials (8997 randomised participants) included in the main analysis of pain indicated that viscosupplementation was associated with a small reduction in pain intensity compared with placebo (SMD −0.08, 95% confidence interval −0.15 to −0.02), with the lower bound of the 95% confidence interval excluding the minimal clinically important between group difference. This effect corresponds to a difference in pain scores of −2.0 mm (95% confidence interval −3.8 to −0.5 mm) on a 100 mm visual analogue scale. Trial sequential analysis for pain indicated that since 2009 there has been conclusive evidence of clinical equivalence between viscosupplementation and placebo. Similar conclusions were obtained for function. Based on 15 large, placebo controlled trials on 6462 randomised participants, viscosupplementation was associated with a statistically significant higher risk of serious adverse events than placebo (relative risk 1.49, 95% confidence interval 1.12 to 1.98). Conclusion: Strong conclusive evidence indicates that viscosupplementation leads to a small reduction in knee osteoarthritis pain compared with placebo, but the difference is less than the minimal clinically important between group difference. Strong conclusive evidence indicates that viscosupplementation is also associated with an increased risk of serious adverse events compared with placebo. The findings do not support broad use of viscosupplementation for the treatment of knee osteoarthritis

DESEMPENHO ECONÔMICO-FINANCEIRO DA PETROBRAS DE 2000 A 2014

RESUMOEste artigo tem como propósito compreender a trajetória de desempenho econômico-financeiro da Petrobras no período de 2000 a 2014. Como base metodológica adotou-se uma abordagem qualitativa e quantitativa, onde as junções dos principais indicadores e de um modelo complementaram a análise econômico-financeira da Petrobras, possibilitando uma classificação de pesquisa do tipo descritiva. Constatou-se que seu portfólio de ativos atribuiu baixa rentabilidade por conta do alto endividamento, sobretudo após o Pré-Sal. Concluiu-se que a Petrobras não representa, no atual momento, uma performance segura a um perfil conservador de investimentos de longo prazo diante de opções na aquisição de ações, cabendo um estudo futuro sobre como caracterizam-se os perfis atuais dos agentes acionistas da Petrobras.Palavras-chave: Petrobras. Análise das Demonstrações. Desempenho econômico-financeiro. ABSTRACTThis paper aims to understand the trajectory of economic and financial performance of Petrobras from 2000 to 2014. As methodological basis was adopted a qualitative and quantitative approach, where the joints of the main indicators and a model complemented the economic and financial analysis of Petrobras, allowing a search ranking of the descriptive type. It was found that its portfolio of assets assigned low profitability due to high debt, especially after the Pré-Sal. It’s concluded that Petrobras is not at present a safe performance to a conservative profile of long-term investments on options management buyout. Fitting, in turn, a future study on how to characterize the current profile of the shareholders of Petrobras agents.Keywords: Petrobras. Analysis of Financial Statements. Economic and financial performance

Disponibilidade de Nutrientes em Neossolo Regolítico sob Sistema Agroecológico com Diferentes Fontes de Adubação

The Regolithic Neosol is the soil that predominates in the Agreste region of Paraiba, these are poorly developed young soils, with low nutrient adsorption power, low organic matter content and high base saturation. These soils are widely used by family farming in the region with the cultivation of subsistence crops and potatoes, thus making it necessary to add agricultural inputs in order to increase soil fertility and organic matter content. The objective was to evaluate the fertility of Neosols cultivated with potatoes submitted to organic and mineral inputs. Soil samples were collected from nine properties in the cities of Areial, Esperança, Montadas and Remígio. After carrying out the collections, the samples were submitted to soil analysis to obtain the levels of N, P, K+, Na+, Ca2+, Mg2+, H+ + Al3+, TOC and physical fractionation of OM. Data were submitted to the Tukey test at a 5% significance level. The pH of the soil had its levels elevated when fertilization with only manure was used, resulting in optimal conditions for the development of the potato crop. In general, the combined use of bovine manure + biofertilizer inputs proved to be effective in N input, maintaining Al3+ levels in the soil close to zero, making more Ca available to the plant and there was a higher OM input when this treatment was used. and treatment only with bovine manure. The combined use of manure + biofertilizer and the use of bovine manure alone were the best treatments for improving the fertility of Regolithic Neosols in the Agreste region of Paraiba.O Neossolo Regolítico é o solo que predomina na região do Agreste Paraibano, esses são solos jovens pouco desenvolvidos, com baixo poder de adsorção de nutrientes, baixo teor de matéria orgânica e alta saturação por base. Esses solos são muito utilizados pela agricultura familiar da região com o cultivo de culturas de subsistência e de batata inglesa, com isso torna-se necessário a adição de insumos agrícolas com o intuito de elevar a fertilidade do solo e o teor de matéria orgânica. Objetivou-se avaliar a fertilidade dos Neossolos cultivados com batata inglesa submetidos a insumos orgânicos e mineral. Foram coletadas amostras de solo em nove propriedades nas cidades de Areial, Esperança, Montadas e Remígio. Após a realização das coletas, as amostras foram submetidas a análise de solo para a obtenção dos teores de N, P, K+, Na+, Ca2+, Mg2+, H++Al3+, COT e fracionamento físico da M.O. Os dados foram submetidos ao teste de Tukey ao nível de 5% de significância. O pH do solo teve seus teores elevados quando se utilizou a adubação apenas com esterco, ficando em condições ótimas para o desenvolvimento da cultura da batata. De modo geral, o uso combinado entre os insumos esterco bovino + biofertilizante se mostrou eficaz no aporte de N, manteve os teores de Al3+ no solo próximo a zero, disponibilizou mais Ca para a planta e houve um maior aporte de M.O quando utilizado este tratamento e o tratamento apenas com esterco bovino. O uso combinado de esterco + biofertilizante e o uso do esterco bovino de forma isolada foram os melhores tratamentos para a melhoria da fertilidade dos Neossolos Regolíticos da Região do Agreste Paraibano

Variabilidade espacial de atributos físicos do solo em terra preta de índio sob cultivo de café conilon

The conversion of natural ecosystems into agricultural systems causes significant changes in soil properties associated with the growing deforestation in the Amazon region influencing the destabilization of the ecosystem. Thus, it is aimed with this study was to evaluate the spatial variability of physical attributes of the soil in black Indian land area (ICC) under Conilon coffee cultivation. It was marked a sampling grid with dimensions of 88 × 64 m, with regular spacing of 8 m, for a total of 88 sampling points, structured and undisturbed soil samples were collected in layers of 0.00 to 0.05; 0.05-0.10; 0.10-0.20 and 0.20-0.30 m. We conducted the following physical analysis: particle size, aggregate stability, total organic carbon (TOC), carbon stock (EstC), macroporosity (MAP), microporosity (MiP), bulk density (Ds), total porosity (PT), soil penetration resistance (RP) and volumetric water content (θ). The results were submitted to descriptive statistical and geostatistical analysis. The ICC’s exhibit great potential that can support the increase in production, since they have excellent soil condition that refers to physical attributes, and evaluated in these layers exhibited no constraint and hindrance to the root culture.A conversão de ecossistemas naturais em sistemas agrícolas provoca alterações significativas nos atributos do solo, associado ao crescente desmatamento na região amazônica influenciando a desestabilidade do ecossistema. Dessa forma, objetivou-se com este estudo avaliar a variabilidade espacial dos atributos físicos do solo em área de terra preta de índio (TPI) sob cultivo de café Conilon. Foi demarcado um grid amostral com dimensões de 88 × 64 m, com espaçamento regular de 8 m, perfazendo um total de 88 pontos amostrais. Foram coletadas amostras estruturadas e indeformadas nas camadas de 0,00-0,05; 0,05-0,10; 0,10-0,20 e 0,20-0,30 m. Realizaram-se as seguintes análises físicas: granulometria, estabilidade de agregados, carbono orgânico total (COT), estoque de carbono (EstC), macroporosidade (MaP), microporosidade (MiP), densidade do solo (Ds), porosidade total (PT), resistência do solo à penetração (RP) e umidade volumétrica (θ). Os resultados foram submetidos à análise estatística descritiva e geoestatística. As TPI’s apresentam grande potencial que podem subsidiar o aumento na produção, visto que estes solos apresentam excelente condição que se refere aos atributos físicos, sendo que nas camadas avaliadas estes não apresentaram nenhuma restrição e impedimento ao sistema radicular da cultura

Spatial dependence of soil attributes in natural field and forest areas, Humaitá, AM

The great geological diversity in Amazonas region generates a variety of soils. Among the various vegetation types in the Amazon, we have in the Southern region, toposequences of natural fields and forests, which includes since grasslands with alternated small trees, to isolated forest galleries along streams. The aim of this study was to use scaled semivariograms in spatial dependence of soil attributes in areas of natural fields and forest in Humaitá, AM region. Sampling networks were established with 64 points, with dimensions of 70 x 70 m and regular spacing of 10 m. The soil was sampled at depths of 0 – 0.05; 0.05 – 0.10 and 0.10 – 0.20 m for the following determinations: macroporosity, microporosity, total porosity, soil moisture, soil resistance penetration (SRP), bulk density, organic carbon, storage carbon and soil organic matter. All variables showed a strong spatial dependence structure in both areas and layers, reaching upper ranges than those established in the mesh. Bulk density (BD) and soil resistance penetration (SRP) in natural field area, can yet cause agricultural problems

Ergonomic assessment of postal workers´ pain symptoms and musculoskeletal risks related to parcel processing activity for delivery

The parcel delivery activity is carried out all over the world and workers in this sector have suffered from musculoskeletal disorders (MSDs) due to the strong demand for work generated by the recent increase in e-commerce. This study aimed to evaluate postal workers' pain symptoms, movements and identify MSDs risks related to the parcel processing activity for delivery, proposing preventive measures. A sample of thirty-two workers was evaluated with the application of sociodemographic and Nordic questionnaires and electrical bioimpedance. The motion capture sensors were used to evaluate right/left shoulder joints, segment C7-T1 (Cervical) and segment L5- S1 (Lumbar) of three postal workers (percentiles of anthropometric data: 5, 50, and 95) during four real work activities that are part of the parcel processing. The analyzed workers presented musculoskeletal complaints in practically all body regions, with a greater prevalence in shoulders, hands, lower back, and knees. According to the Body Mass Index (BMI), they were on average overweight (27.8 ± 3.7 kg/m2 ). In the movement analysis, we identified risks related to cervical protrusion, anterior trunk flexion, and shoulder flexion, in addition to repetitive movements. In some activities, the higher stature showed an increase in lumbar and cervical anterior flexion. The set of evaluations showed that the activity of processing orders for delivery offers musculoskeletal risks. We identify that ergonomic adaptations are necessary to adapt the heights of the work environment to the statures of the postal workers. Relevance to industry: The activity of processing orders for delivery is carried out practically all over the world generating jobs and income for its employees. Nonetheless, there are still situations of ergonomic disadvantage that can generate musculoskeletal risks. The findings elucidate ergonomic risks and provide useful information for future ergonomic interventions in the postal/delivery workplace environment.ECT -Eaga Charitable Trust(undefined