920 resultados para Monitoring of Structures
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tool Condition Monitoring of Single-Point Dresser Using Acoustic Emission and Neural Networks Models
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The grinding operation gives workpieces their final finish, minimizing surface roughness through the interaction between the abrasive grains of a tool (grinding wheel) and the workpiece. However, excessive grinding wheel wear due to friction renders the tool unsuitable for further use, thus requiring the dressing operation to remove and/or sharpen the cutting edges of the worn grains to render them reusable. The purpose of this study was to monitor the dressing operation using the acoustic emission (AE) signal and statistics derived from this signal, classifying the grinding wheel as sharp or dull by means of artificial neural networks. An aluminum oxide wheel installed on a surface grinding machine, a signal acquisition system, and a single-point dresser were used in the experiments. Tests were performed varying overlap ratios and dressing depths. The root mean square values and two additional statistics were calculated based on the raw AE data. A multilayer perceptron neural network was used with the Levenberg-Marquardt learning algorithm, whose inputs were the aforementioned statistics. The results indicate that this method was successful in classifying the conditions of the grinding wheel in the dressing process, identifying the tool as "sharp''(with cutting capacity) or "dull''(with loss of cutting capacity), thus reducing the time and cost of the operation and minimizing excessive removal of abrasive material from the grinding wheel.
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Objective This study assessed early manifestations of metabolic syndrome determinants in patients submitted to hematopoietic stem cell transplantation. Methods Twenty-seven individuals participated in the study (20 with autologous and 7 with allogeneic hematopoietic stem cell transplantation). Anthropometric variables and biochemical indicators of lipid and glucose metabolism were determined before and 100 days after hematopoietic stem cell transplantation.Results The mean total cholesterol (p=0.086), very low density lipoprotein-cholesterol (p=0.069) and triglycerides (p=0.086) of all patients did not change significantly between the two study periods, but when the patients were separated by type of hematopoietic stem cell transplantation, triglycerides and very low density lipoprotein-cholesterol were close to the critical level of significance for individuals with allogeneic hematopoietic stem cell transplantation (p=0.060) and total cholesterol was significant in individuals with autologous hematopoietic stem cell transplantation (p=0.027). Anthropometric variables did not change significantly between before and 100 days after hematopoietic stem cell transplantation. Conclusion Metabolic syndrome risk factors may be associated with lipid metabolism in the early phase of allogeneic and autologous hematopoietic stem cell transplantation.
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An epidemiological survey for the monitoring of bovine tuberculosis transmission was carried out in western Liguria, a region in northern Italy. Fifteen Mycobacterium bovis strains were isolated from 63 wild boar samples (62 from mandibular lymph nodes and 1 from a liver specimen). Sixteen mediastinal lymph nodes of 16 head of cattle were collected, and 15 Mycobacterium bovis strains were subsequently cultured. All M. bovisstrains isolated from cattle and wild boars were genotyped by spoligotyping and by restriction fragment length polymorphism (RFLP) analysis with the IS6110 and IS1081 probes. All M. bovis strains showed the typical spoligotype characterized by the absence of the 39 to 43 spacers in comparison with the number in M. tuberculosis. A total of nine different clusters were identified by spoligotyping. The largest cluster included 9 strains isolated from wild boars and 11 strains isolated from cattle, thus confirming the possibility of transmission between the two animal species. Fingerprinting by RFLP analysis with the IS6110 probe showed an identical single-band pattern for 29 of 30 strains analyzed, and only 1 strain presented a five-band pattern. The use of IS1081 as a second probe was useful for differentiation of M. bovis from M. bovis BCG but not for differentiation among M. bovis strains, which presented the same undifferentiated genomic profile. In relation to the epidemiological investigation, we hypothesized that the feeding in pastures contaminated by cattle discharges could represent the most probable route of transmission of M. bovis between the two animal species. In conclusion, our results confirmed the higher discriminatory power of spoligotyping in relation to that of RFLP analysis for the differentiation of M. bovis genomic profiles. Our data showed the presence of a common M. bovis genotype in both cattle and wild boars, confirming the possible interspecies transmission of M. bovis.
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Drought is not an unusual phenomenon on the Canadian prairies or the U.S. Great Plains. There were many short-term droughts in the prairies during the 20th century that generally lasted one to two years (e.g., 1961, 1988). The Canadian prairies multi-year drought event (1999-2003+) has been considered similar in severity to the 1930s drought years. The 2004 Prairie Drought Workshop resulted in 76 scientists and resource managers gathering in Calgary, Alberta, to share information on drought science, impacts, and monitoring. Presenters examined the impacts on agriculture, stream flow, forests, and ground water, including potential impacts under a changed climate. Though focused on the Canadian prairies, the information presented could be applied to many parts of the U.S. Great Plains.
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When a scaled structure (model or replica) is used to predict the response of a full-size compound (prototype), the model geometric dimensions should relate to the corresponding prototype dimensions by a single scaling factor. However, owing to manufacturing technical restrictions, this condition cannot be accomplished for some of the dimensions in real structures. Accordingly, the distorted geometry will not comply with the overall geometric scaling factor, infringing the Pi theorem requirements for complete dynamic similarity. In the present study, a method which takes geometrical distortions into account is introduced, leading to a model similar to the prototype. As a means to infer the performance of this method, three analytical problems of structures subjected to dynamic loads are analysed. It is shown that the replica developed applying this technique is able to accurately predict the full-size structure behaviour even when the studied models have some of their dimensions severely distorted. (C) 2012 Elsevier Ltd. All rights reserved.
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The banana weevil Cosmopolites sordidus (Germar) is one of a number of pests that attack banana crops. The use of the entomopathogenic fungus Beauveria bassiana as a biological control agent for this pest may contribute towards reducing the application of chemical insecticides on banana crops. In this study, the genetic variability of a collection of Brazilian isolates of B. bassiana was evaluated. Samples were obtained from various geographic regions of Brazil, and from different hosts of the Curculionidae family. Based on the DNA fingerprints generated by RAPD and AFLP, we found that 92 and 88 % of the loci were polymorphic, respectively. The B. bassiana isolates were attributed to two genotypic clusters based on the RAPD data, and to three genotypic clusters, when analyzed with AFLP. The nucleotide sequences of nuclear ribosomal DNA intergenic spacers confirmed that all isolates are in fact B. bassiana. Analysis of molecular variance showed that variability among the isolates was not correlated with geographic origin or hosts. A RAPD-specific marker for isolate CG 1024, which is highly virulent to C. sordidus, was cloned and sequenced. Based on the sequences obtained, specific PCR primers BbasCG1024F (5'-TGC GGC TGA GGA GGA CT-3') and BbasCG1024R (5'-TGC GGC TGA GTG TAG AAC-3') were designed for detecting and monitoring this isolate in the field.
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Objectives: Over the last years, it is known that in some cases metal devices for biomedical applications present some disadvantages suggesting absorbable materials (natural or synthetic) as an alternative of choice. Here, our goal was to evaluate the biological response of a xenogenic pin, derived from bovine cortical bone, intraosseously implanted in the femur of rats. Material and methods: After 10, 14, 30 and 60 days from implantation, the animals (n = 5/period) were killed and the femurs carefully collected and dissected out under histological demands. For identifying the osteoclastogenesis level at 60 days, we performed the immunohistochemisty approach using antibody against RANKL. Results: Interestingly, our results showed that the incidence of neutrophils and leukocytes was observed only at the beginning (10 days). Clear evidences of pin degradation by host cells started at 14 days and it was more intensive at 60 days, when we detected the majority of the presence of giant multinucleated cells, which were very similar to osteoclast cells contacting the implanted pin. To check osteoclastogenesis at 60 days, we evaluated RANKL expression and it was positive for those resident multinucleated cells while a new bone deposition was verified surrounding the pins in all evaluated periods. Conclusions: Altogether, our results showed that pins from fully processed bovine bone are biocompatible and absorbable, allowing bone neoformation and it is a promissory device for biomedical applications.
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Background. This study evaluated the influence of circulating anti-HLA antibodies on outcomes of 97 liver allografts from deceased donors. Methods. Human leukocyte antigen (HLA) antibody screening was performed by both complement-dependent cytotoxicity (CDC) and multiparameter Luminex microsphere-based assays (Luminex assay). Results. The agreements between T- and B- cell CDC and Luminex assays were 67% and 77% for pre- and posttransplant specimens, respectively. Graft dysfunction was not associated with either positive pretransplant CDC or Luminex panel-reactive antibody (PRA) values. Likewise, positive posttransplant T- or B- cell CDC PRA values were not associated with graft dysfunction. In contrast, posttransplant Luminex PRA values were significantly higher among patients with graft dysfunction compared with subjects with good outcomes (P = .017). Conclusion. Posttransplant monitoring of HLA antibodies with Luminex methodology allowed identification of patients at high-risk for poor graft outcomes.
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Abstract Background A typical purification system that provides purified water which meets ionic and organic chemical standards, must be protected from microbial proliferation to minimize cross-contamination for use in cleaning and preparations in pharmaceutical industries and in health environments. Methodology Samples of water were taken directly from the public distribution water tank at twelve different stages of a typical purification system were analyzed for the identification of isolated bacteria. Two miniature kits were used: (i) identification system (api 20 NE, Bio-Mérieux) for non-enteric and non-fermenting gram-negative rods; and (ii) identification system (BBL crystal, Becton and Dickson) for enteric and non-fermenting gram-negative rods. The efficiency of the chemical sanitizers used in the stages of the system, over the isolated and identified bacteria in the sampling water, was evaluated by the minimum inhibitory concentration (MIC) method. Results The 78 isolated colonies were identified as the following bacteria genera: Pseudomonas, Flavobacterium and Acinetobacter. According to the miniature kits used in the identification, there was a prevalence of isolation of P. aeruginosa 32.05%, P. picketti (Ralstonia picketti) 23.08%, P. vesiculares 12.82%,P. diminuta 11.54%, F. aureum 6.42%, P. fluorescens 5.13%, A. lwoffi 2.56%, P. putida 2.56%, P. alcaligenes 1.28%, P. paucimobilis 1.28%, and F. multivorum 1.28%. Conclusions We found that research was required for the identification of gram-negative non-fermenting bacteria, which were isolated from drinking water and water purification systems, since Pseudomonas genera represents opportunistic pathogens which disperse and adhere easily to surfaces, forming a biofilm which interferes with the cleaning and disinfection procedures in hospital and industrial environments.