AVALIAÇÃO DE TENACIDADE À FRATURA DA LIGA ALUMÍNIO 7075-T651 ATRAVÉS DO PARÂMETRO CTOD, PARA IDENTIFICAÇÃO DE APLICAÇÕES DE ALTA RESPONSABILIDADE

Atualmente, a busca pela prevenção de erros vem se demonstrando cada vez mais necessária. Com isso, quando há fabricação de elementos mecânicos com o intuito de suportar situações adversas em serviço deve haver cuidados quanto a tenacidade à fratura da peça. A tenacidade à fratura de um material corresponde a sua capacidade de absorver energia quando submetido a tensões que possam ocasionar sua fratura. A ocorrência de fraturas está ligada a diversos fatores, sendo um dos mais comuns o fenômeno da fadiga. Dentre as propriedades mecânicas analisadas em metais, o valor equivalente a tenacidade torna-se útil para estabelecer um limite de segurança onde não há risco da ocorrência de rupturas. A Mecânica da Fratura fornece métodos para a obtenção desses valores por meio de dois eixos de estudo inseridos em sua área de conhecimento, sendo eles a Mecânica da Fratura Linear Elástica (MFLE) e a Mecânica da Fratura Elasto-plástica (MFEP). O presente projeto tem como objetivo obter e analisar o valor da propriedade mecânica em questão da liga de alumínio 7075 T651 utilizando o parâmetro CTOD, esse parâmetro baseia se na medição do início da propagação da trinca do material, baseado na sua concentração de tensões, cálculo desenvolvido pela MFEP. Após a obtenção das características mecânicas e metalúrgicas do material, são confeccionados os corpos de provas que são submetidos aos ensaios de tração, flexão por três pontos e fadiga respectivamente, cujo os valores fornecidos são utilizados para o desenvolvimento da equação. O arranjo produtivo local (APL) é caracterizado principalmente pela presença de indústrias do ramo metal-mecânico, desenvolver a análise proposta contribui para expandir e aprimorar a qualificação dos materiais utilizados em seus maquinários, aumentando a produtividade e reduzindo a suscetibilidade a ocorrência de falhas e possíveis prejuízos. Devido a pandemia que se instaurou e todos os empecilhos que ela impôs, osensaios bem como a resolução do cálculo do método CTOD, não foram possíveis de se concluírem

Influence of the Location of the Internal Temperature Control Loop on the Performance of the Dual Temperature Control for Feed Temperature Disturbance

A control strategy with distributed corrective action for distillation has been proposed and consists of a conventional dual temperature control combined with an additional column tray. In this work, we evaluated the influence of the location of this internal loop as part of the new proposal, compared to a conventional system. Tests were carried out in a 13-column tray distillation equipment and feed temperature was disturbed. Two different column trays from the stripping section were used (11 and 12) for internal decentralized temperature control, each one separately, plus the dual control of top and bottom temperatures. The results demonstrated that this proposed control approach with distributed corrective action is faster than the conventional one, regardless of the column tray in use. It was also determined that the internal loop close to the feed (disturbance) is more interesting as a way to minimize transients

Effects of glycerol and creatine hyperhydration on doping-relevant blood parameters

Glycerol is prohibited as an ergogenic aid by the World Anti-Doping Agency (WADA) due to the potential for its plasma expansion properties to have masking effects. However, the scientific basis of the inclusion of Gly as a “masking agent” remains inconclusive. The purpose of this study was to determine the effects of a hyperhydrating supplement containing Gly on doping-relevant blood parameters. Nine trained males ingested a hyperhydrating mixture twice per day for 7 days containing 1.0 g•kg<sup>−1</sup> body mass (BM) of Gly, 10.0 g of creatine and 75.0 g of glucose. Blood samples were collected and total hemoglobin (Hb) mass determined using the optimized carbon monoxide (CO) rebreathing method pre- and post-supplementation. BM and total body water (TBW) increased significantly following supplementation by 1.1 ± 1.2 and 1.0 ± 1.2 L (BM, P < 0.01; TBW, P < 0.01), respectively. This hyperhydration did not significantly alter plasma volume or any of the doping-relevant blood parameters (e.g., hematocrit, Hb, reticulocytes and total Hb-mass) even when Gly was clearly detectable in urine samples. In conclusion, this study shows that supplementation with hyperhydrating solution containing Gly for 7 days does not significantly alter doping-relevant blood parameters

Manejo de pomares de macieira sob diferentes cores de tela antigranizo: avaliação da qualidade pós-colheita.

A macieira (Malus domestica) é cultivada em regiões de altitude, onde a ocorrência de granizo é elevada, o que causa grandes prejuízos aos pomares. O objetivo desse trabalho foi avaliar a qualidade de maçãs ?Fuji Suprema? produzidas sob diferentes telas antigranizo

BIODIGESTÃO ANAERÓBIA DE RESÍDUOS LÍQUIDOS DE FECULARIA COM ADIÇÃO DE GLICEROL EM FASE TERMOFÍLICA

A conscientização sobre o meio ambiente ganhou lugar de destaque no cenário mundial nas décadas de 60 e 70, sendo que protegê-lo passou a ser um dos princípios fundamentais do homem moderno, fazendo com que estes se preocupem não apenas com o controle e mitigação de seus impactos, mas também com o desempenho ambiental que gera o conceito de desenvolvimento sustentável. Grande parte das fontes de energia utilizada atualmente no mundo refere-se a fontes não renováveis, contudo, a busca crescente por outras formas desta tem levado ao desenvolvimento de pesquisas que possam ser utilizadas com a finalidade de produzir biocombustíveis. A biodigestão anaeróbia é uma das alternativas para produção de energia com maior potencial para os próximos anos, é considerada uma das principais saídas para diversificação da matriz energética, proporcionando a diminuição da dependência dos combustíveis fósseis. Foi realizado experimentos em reatores de bancada operando em alimentação batelada (3,2 L de volume útil) com resíduo líquido proveniente de fecularia com adição de glicerol (0%, 1%, 3%, 5% e 7%) resíduo da produção de biodiesel, em fase termofílica avaliando o aumento de produção de biogás conforme a variação na concentração de glicerol adicionado. O tempo de retenção hidráulica (TRH) foi de 12 dias, onde o experimento número 3, com adição de 3% de glicerol apresentou a maior produção de biogás com um total de 5,779 ml. Podemos observar que a adição de glicerol favoreceu a produção de biogás, mas concentrações acima de 3% não apresentaram resultados satisfatórios

Ehrlich ascites tumor-bearing mice treated with aqueous ethanol plant extract from Euphorbia tirucalli showed signs of systemic toxicity

Purpose: To evaluate the antitumor effect of a latex extract from Euphorbia tirucalli Linn. (Euphorbiaceae) and its toxicity.Methods: Aqueous ethanol and petroleum ether extracts were obtained through maceration. .Maximum tolerated dose was determined in healthy mice. Antitumor activity was measured in Ehrlich ascites tumor-bearing mice treated with the extract through intraperitoneal injection (62.5, 125 or 250 mg/kg) every 48 h (four doses). Efficacy was assessed by weight gain, abdominal circumference, volume of ascitic fluid and packed tumor cells, tumor cell viability and survival. Toxicity indicators were serum glucose, triglycerides, total proteins, activity of alanine and aspartate aminotransferases and mass of heart, spleen, kidney and liver. A hemolysis assay was also performed.Results: Doses of 62.5 and 125 mg/kg caused no antitumor activity, while 250 mg/kg dose reduced weight gain (3-fold), abdominal circumference and volume of ascitic fluid (> 50 %) and packed cells (50 %), but lowered tumor cell viability (40 %). However, mice treated with the extract survived for a shorter time than control mice. Furthermore, the 250 mg/kg dose caused cardiac atrophy, splenomegaly and fasting hyperglycemia. The extract caused hemolysis, and the half-maximal effective concentration (EC50) was 1.6 (0.9 – 2.7) mg/mL.Conclusion: Euphorbia tirucalli extract inhibits Ehrlich ascites tumor in mice, but the therapeutic dose is also harmful to non-tumor tissues.Keywords: Euphorbia tirucalli, Ehrlich ascites tumor-bearing mice, Antitumor, Toxicity, Cardiac atrophy, Splenomegal

Cárie dentária e fatores relacionados em crianças Brasileiras de região com água fluoretada e não fluoretada

PURPOSE: To compare the caries prevalence, saliva buffering capacity (SBC), oral hygiene (OH), dietary habits, family income (FI) and frequency of visits to a dental office (Do) between Brazilian children living in areas with and without fluoridated public water supply. METHODS: Forty-six 5-7-year-old preschoolers were selected in Itatiba, SP, Brazil; 19 were from a fluoridated area, and 27 were from a non-fluoridated area. The caries index was determined according to the World Health Organization criteria, and the SBC was assessed by titration with hydrochloric acid. The FI, frequency of OH and visits to Do were estimated by questionnaire. The dietary habits were assessed with a diet chart. The differences between the groups were analyzed with Mann-Whitney-U tests (α=0.05). RESULTS: Children from the non-fluoridated area showed significantly higher dmft/DMFT than those from the fluoridated area, but they showed significantly lower SBC, OH frequency and FI. No significant differences were observed between the areas for dietary habits and visits to Do. CONCLUSION: Children from fluoridated areas showed higher salivary buffering capacity, family income and oral hygiene frequency as well as lower caries prevalence, supporting the beneficial effect of fluoride in the tap water for caries prevention.OBJETIVO: Comparar prevalência de cárie, capacidade tamponante da saliva (CTS), higiene bucal (HB), hábitos dietéticos, renda familiar (RF) e frequência de visita a consultórios odontológicos (Co) entre crianças brasileiras residentes em áreas de água de abastecimento público fluoretadas e não fluoretadas. METODOLOGIA: Quarenta e seis crianças entre 5-7 anos foram selecionadas em Itatiba-SP-Brasil, sendo 19 pertencentes à área fluoretada e 27 à área não fluoretada. O índice de cárie foi determinado de acordo com o critério da Organização Mundial de Saúde e a CTS foi medida por titulação com ácido clorídrico. A RF, frequência de HB e visita ao Co foram estimadas por questionário. Os hábitos dietéticos foram avaliados com diário de dieta. As diferenças entre as variáveis foram analisadas pelo teste de Mann Whitney (α=0,05). RESULTADOS: As crianças da área não fluoretada apresentaram significativamente maior ceod/CPOD que àquelas da área fluoretada, porém significativamente menor CTS, HB e RF. Com relação a hábitos dietéticos e visitas ao Co, não foi observada diferença significativa entre as áreas. CONCLUSÃO: As crianças da área fluoretada apresentaram maior capacidade tamponante da saliva, renda familiar e frequência de higiene bucal, assim como menor prevalência de cárie, reforçando o efeito benéfico do flúor nas águas de abastecimento para prevenir a cárie

Haemoglobin mass and running time trial performance after recombinant human erythropoietin administration in trained men

<p>Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hbmass) and maximal oxygen uptake (v˙ O2 max).</p> <p>Purpose: This study defined the time course of changes in Hbmass, v˙ O2 max as well as running time trial performance following 4 weeks of rHuEpo administration to determine whether the laboratory observations would translate into actual improvements in running performance in the field.</p> <p>Methods: 19 trained men received rHuEpo injections of 50 IUNkg21 body mass every two days for 4 weeks. Hbmass was determined weekly using the optimized carbon monoxide rebreathing method until 4 weeks after administration. v˙ O2 max and 3,000 m time trial performance were measured pre, post administration and at the end of the study.</p> <p>Results: Relative to baseline, running performance significantly improved by ,6% after administration (10:3061:07 min:sec vs. 11:0861:15 min:sec, p,0.001) and remained significantly enhanced by ,3% 4 weeks after administration (10:4661:13 min:sec, p,0.001), while v˙ O2 max was also significantly increased post administration (60.765.8 mLNmin21Nkg21 vs. 56.066.2 mLNmin21Nkg21, p,0.001) and remained significantly increased 4 weeks after rHuEpo (58.065.6 mLNmin21Nkg21, p = 0.021). Hbmass was significantly increased at the end of administration compared to baseline (15.261.5 gNkg21 vs. 12.761.2 gNkg21, p,0.001). The rate of decrease in Hbmass toward baseline values post rHuEpo was similar to that of the increase during administration (20.53 gNkg21Nwk21, 95% confidence interval (CI) (20.68, 20.38) vs. 0.54 gNkg21Nwk21, CI (0.46, 0.63)) but Hbmass was still significantly elevated 4 weeks after administration compared to baseline (13.761.1 gNkg21, p<0.001).</p> <p>Conclusion: Running performance was improved following 4 weeks of rHuEpo and remained elevated 4 weeks after administration compared to baseline. These field performance effects coincided with rHuEpo-induced elevated v˙ O2 max and Hbmass.</p&gt

Hydroxychloroquine drastically reduces immune activation in HIV-infected, antiretroviral therapy-treated immunologic nonresponders

Despite optimal suppression of HIV replication, restoration of CD4(+) T cells is not always achieved in antiretroviral therapy-treated individuals. Defective CD4 recovery in immunologic nonresponders is possibly associated with TLR-mediated immune activation driven by alterations of gut permeability. Hydroxychloroquine (HCQ) reduces endosomal TLR signaling; thus, we verified whether HCQ could dampen immune activation and be associated with an increase in CD4(+) T cells. To this end, we enrolled in a prospective study 20 HIV-infected immunologic nonresponders (CD4 count < 200 cells/mL or CD4 increase < 5% in the last 12 months) who received 400 mg/day HCQ for 6 months. HCQ had a notable impact on immune activation as shown by significant modifications of the following parameters: (1) reduced plasma lipopolysaccharide; (2) decreased TLR4-expressing CD14(+) cells, TLR4-mediated signal transduction, and mRNA synthesis; (3) reduced percentages of activated CD4(+) (CD4(+)/Ki67(+)) and CD14(+) (CD14(+)/CD69(+)) cells; (4) increased T-regulatory cells (Tregs), naive Tregs, and TLR4-expressing Tregs; (5) augmented plasmacytoid dendritic cells and reduced IFN alpha-secreting plasmacytoid dendritic cells; and (6) reduced IL-6 and TNF alpha production. HCQ-induced immune modulation was associated with increased percentages of circulating CD4(+) T cells and was mostly retained 2 months after therapy interruption. HCQ reduces lipopolysaccharide/TLR-mediated immune activation; this compound could be a useful immunomodulant in HIV-infected patients. This study is registered at EutraCT as 2009-012499-28 with study number HLS01/2009-1-16-03-2009. (Blood. 2011;118(12):3263-3272