Modelagem Multiescala de Falha Dinâmica em Materiais Metálicos

CCES Newsletter - June 201

Mitogenomics of southern hemisphere blue mussels (Bivalvia: Pteriomorphia): Insights into the evolutionary characteristics of the Mytilus edulis complex

Marine blue mussels (Mytilus spp.) are widespread species that exhibit an antitropical distribution with five species occurring in the Northern Hemisphere (M. trossulus, M. edulis, M. galloprovincialis, M. californianus and M. coruscus) and three in the Southern Hemisphere (M. galloprovincialis, M. chilensis and M. platensis). Species limits in this group remain controversial, in particular for those forms that live in South America. Here we investigated structural characteristics of marine mussels mitogenomes, based on published F mtDNA sequences of Northern Hemisphere species and two newly sequenced South American genomes, one from the Atlantic M. platensis and another fr om the Pacific M. chilensis. These mitogenomes exhibited similar architecture to those of other genomes of Mytilus, including the presence of the Atp8 gene, which is missing in most of the other bivalves. Our evolutionary analysis of mitochondrial genes indicates that purifying selection is the predominant force shaping the evolution of the coding genes. Results of our phylogenetic analyses supported the monophyly of Pteriomorphia and fully resolved the phylogenetic relationships among its five orders. Finally, the low genetic divergence of specimens assigned to M. chilensis and M. platensis suggests that these South American marine mussels represent conspecific variants rather than distinct species.Link_to_subscribed_fulltex

Multiscale model of the role of grain boundary structures in the dynamic intergranular failure of polycrystal aggregates

National Council for Scientific and Technological Development-CNPq, Brazil (grant numbers: 312493/2013-4, 154283/2014-2); the Coordination for the Improvement of Higher Education Personnel-CAPES, Brazil (grant number: 88882.329019/2019-01

Flow Diverter Treatment for Non-Ruptured Carotid Aneurysms: Efficacy and Safety

Purpose Internal carotid artery (ICA) aneurysm treatment with a flow diverter (FD) has shown an adequate efficacy and safety profile, presenting high complete occlusion or near occlusion rates with low complications during follow-up. The purpose of this study was to evaluate the efficacy and safety of FD treatment in non-ruptured internal carotid aneurysms. Materials and Methods This is a retrospective, single-center, observational study evaluating patients diagnosed with unruptured ICA aneurysms treated with an FD between January 1, 2014, and January 1, 2020. We analyzed an anonymized database. The primary effectiveness endpoint was complete occlusion (O’Kelly–Marotta D, OKM-D) of the target aneurysm through 1-year follow-up. The safety endpoint was the evaluation of modified Rankin Scale (mRS) 90 days after treatment, considering a favorable outcome an mRS 0-2. Results A total of 106 patients were treated with an FD, 91.5% were women; the mean follow- up was 427.2±144.8 days. Technical success was achieved in 105 cases (99.1%). All patients included had 1-year follow-up digital subtraction angiography control; 78 patients (73.6%) completed the primary efficacy endpoint by achieving total occlusion (OKM-D). Giant aneurysms had a higher risk of not achieving complete occlusion (risk ratio, 3.07; 95% confidence interval, 1.70 - 5.54]). The safety endpoint of mRS 0-2 at 90 days was accomplished in 103 patients (97.2%). Conclusion Treatment of unruptured ICA aneurysms with an FD showed high 1-year total occlusion results, with very low morbidity and mortality complications

Analysis of two-dimensional fatigue crack propagation in thin aluminum plates using the Paris law modified by a closure concept

A general procedure is applied to analyze fatigue crack propagation in isotropic materials under mixed mode conditions, the Paris law modified by a closure concept. The dual boundary element method (DBEM) provides an stress and strain analysis on the solid, with reliable results for the mechanical fields in the region near to the crack tip. For validating purposes, thin plates made of 2024-T3 aluminum alloy are used with two horizontal notches. Throughout the J-Integral the stress intensity factors (SIFs) can be evaluated and with digital image processing, the displacement information from the experimental tests is obtained. Then, the effect of the crack closure during unloading is considered to attain remarkable numerical results compared to those experimentally collected, showing the feasibility of the proposed model106513527CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPNational Council for Scientific and Technological Development (CNPq)National Council for Scientific and Technological Development (CNPq); Sao Paulo Research Foundation (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Brazilian Coordination for the Improvement of Higher Education Personnel (CAPES)CAPES; Air Force Office of Scientific ResearchUnited States Department of DefenseAir Force Office of Scientific Research (AFOSR) [FA9550-18-1-0113

A consistent multiphase SPH approximation for bubble rising with moderate Reynolds numbers

Phenomena involving bubble flow have an important role in numerous applications such as mixing, separation, filtration and cooling. When two different phases are treated as liquids gas, the surface tension and buoyancy must be taken into account. An alternative is proposed to simulate flow for two or more phases, using bubbles formation and the Navier Stokes equations in a Lagrangian formalism via smoothed particle hydrodynamics (SPH). It is a mesh-free method useful for applications with interface flow. Therefore, we have presented a set of numerical methodologies for SPH in multiphases. Surface tension interface is modeled using the continuum surface force (CSF) method. In order to avoid tension instability and interface penetrations, a background pressure based on the initial pressure between phases is included in the formulation. This model is implemented inside the prediction correction of time upgrade scheme. Examples of bubble rising around the fluid due to the gravitational force are rarely analyzed in the SPH literature, especially to parameterize density, viscosity, surface coefficient, particle size and boundary conditions. Thus, this work focus on the analysis of these parameters and their effects on the morphology, displacement and velocity of the bubble simulations. Finally, results demonstrate a good numerical stability and adequate multiphase description105119CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP54283/2014-22012/21090-

Cultivation of Chlorella vulgaris in Aquaculture Wastewater for Protein Production

Microalgae have emerged as environment friendly alternative source of valuable products for energy, pharmaceutical and cosmetic industries. These microorganisms have been also studied in wastewater treatments due to its ability to remove CO2, nitrogen, phosphorus, and toxic metals. In this work, cultivation of microalgae Chlorella vulgaris was carried out in aquaculture wastewater in order to reduce its contents of NO3 and PO4. In addition, different concentration of inorganic carbon sources (NaHCO3 and Na2CO3) and addition times were considered for determining suitable conditions in microalgae culture to produce proteins. It was found that highest protein content (45 % w/w) was achieved at 3.4 g/L of NaHCO3 and 19 h of addition time