Parallel structurally-symmetric sparse matrix-vector products on multi-core processors

We consider the problem of developing an efficient multi-threaded implementation of the matrix-vector multiplication algorithm for sparse matrices with structural symmetry. Matrices are stored using the compressed sparse row-column format (CSRC), designed for profiting from the symmetric non-zero pattern observed in global finite element matrices. Unlike classical compressed storage formats, performing the sparse matrix-vector product using the CSRC requires thread-safe access to the destination vector. To avoid race conditions, we have implemented two partitioning strategies. In the first one, each thread allocates an array for storing its contributions, which are later combined in an accumulation step. We analyze how to perform this accumulation in four different ways. The second strategy employs a coloring algorithm for grouping rows that can be concurrently processed by threads. Our results indicate that, although incurring an increase in the working set size, the former approach leads to the best performance improvements for most matrices.Comment: 17 pages, 17 figures, reviewed related work section, fixed typo

Study of PDMS characterization and its applications in biomedicine: a review

Polydimethylsiloxane, also known as PDMS, has been widely used in the biomedical industry because of its biocompatible material and its biomechanical behavior is similar to biological tissues, with applications in the study of aneurysmal behavior and devices such as: Micro pumps, optical systems, microfluidic circuits. Many advances in research have been reached, but further tests are still necessary to understand the mechanical behavior and applicability of the material. For the study of PDMS behavior, two different techniques are employed: numerical and experimental. In experimental studies, it is extremely popular to use a field technique, in which the most appropriate technique to measure the field displacement of PDMS, without decorrelation, is the Digital Image Correlation (DIC) method. In this paper, we revised the most important experimental works with PDMS material and, simultaneously, we present its mechanical properties and its biomedical applications.info:eu-repo/semantics/publishedVersio

Numerical characterization of a hyperelastic material to shear stress

In last years, some studies have been proved that there is an association between the wall shear stress with intracranial aneurysm rupture, however, is very difficult to understand the mechanical tissue behaviour when subjected to shear stresses. In this work, it is implemented numerical simulations to characterise the polydimethylsiloxane (PDMS) material when it is subjected to a shear solicitation. For this, it was initially necessary to perform some experimental tests to characterize the mechanical behaviour of the material. Based on these results, several numerical simulations were performed with the most common constitutive models in the simulation of hyperelastic materials by varying numerical factors and parameters of the numerical models.info:eu-repo/semantics/publishedVersio

Espumas cerâmicas como suportes catalíticos

Espumas reticulares de cordierite desenvolvidas por um método de polimerização “in situ” revelaram propriedades de elevado interesse para a aplicação como suportes catalíticos. Estas espumas são caracterizadas por possuírem porosidades superiores (>90%) às obtidas pelo método de replicação polimérica (70-85%). O desenvolvimento de um método de revestimento de espumas cerâmicas com catalisadores zeolíticos, e a optimização de parâmetros como teor de sólidos, ligante, surfactante ou pré-revestimento da espuma, tem estado a ser efectuado. As melhores características foram observadas para espumas com aproximadamente 17% (p/p) de revestimento obtidas a partir de suspensões com cerca de 16% de teor de sólidos. Espumas revestidas com zeólitos Pt/ZSM5 estão a ser utilizadas como catalisadores para a combustão catalítica de COVs, nomeadamente isopropanol e toluen

A new calculation method for the temperature of the components of composite slabs under fire

Composite steel-concrete slabs are structural elements composed of a profiled steel deck which acts as a permanent formwork to the concrete topping. This layer is commonly reinforced with individual rebars and an anti-crack mesh. The Annex D of the EN 1994-1-2 provides guidelines for the calculation of the temperature of the steel components of composite slabs subjected to the standard fire. However, no revisions were made to these calculation rules during the last years. This paper proposes a new method for the estimation of the temperature of the parts of the steel deck and the rebars as well. The proposed methodology is derived from numerical analyses using a 3-D finite element model, considering perfect thermal contact between the materials.info:eu-repo/semantics/publishedVersio

Reuse of effluent from dyeing process of polyamide fibers modified by double barrier discharge (DBD) plasma

Published online: 27 Feb 2015Low-temperature plasma technology becomes more and more attractive compared with traditional wet processes in textile preparation and finishing due to its high efficiency and low environmental impact. The objective of this study was to investigate the influence of dielectric barrier discharge plasma treatment on the trichromic dyeing process of polyamide 6.6 (PA66) and the reuse of the generated effluents for new dyeing processes. Chemical and physical characterization of the plasma-treated polyamide fibers was studied by means of static and dynamic contact angle, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy micrographs, and atomic force microscopy (AFM). Plasma treatment greatly increases the hydrophilicity and adhesion of PA66, due to the increase of polar groups and roughness on the fibers surface as confirmed by XPS and AFM. The kinetics of dyeing is quicker but leveled with high rubbing, light, and washing fastness quality. The reuse of the effluent obtained after dyeing of the plasma-treated fabrics showed excellent results of reproducibility, uniformity, and washing fastness. It was possible to reproduce the standard color for three dyeing cycles using the same effluent reducing the effluent load with a significant diminution in costs and environmental impact.Andrea Zille (C2011- UMINHO-2C2T-01) acknowledges funding from Programa Compromisso para a Ciencia 2008, Portugal

Evaluation of a simplified model for estimating energy balance in broilers production housing

The simulation of poultry house thermal behavior with and without Adiabatic Evaporative Cooling (SRAE) allows the decision makers to evaluate the economical feasibility and the installation costs of a poultry production business. The first step in this research investigation was test the thermal behavior model developed by Gates et al. (1995) for broiler houses in the United States based on the hypothesis that this model, using climatized sheds, as proposed by the authors, could be used under Brazilian conditions. The model is suitable for the proposed objective in the form proposed by Gates et al. (1995) for poultry houses with an elevated mass air flow rate (120.8 kg air s -1 or higher). A correction factor referring to a series of heat sources not included in the model, or the inclusion of these sources, is necessary for poultry houses without a high mass air flow.A simulação do comportamento térmico de galpões avícolas com e sem Sistemas de Resfriamento Adiabáticos Evaporativos (SRAE) permite aos tomadores de decisão avaliarem a viabilidade econômica e os custos da instalação de um empreendimento na avicultura de corte. Para operacionalização desta investigação, o primeiro passo foi a execução do teste do modelo de comportamento térmico desenvolvido por Gates et al. (1995) para galpões avícolas nos Estados Unidos, com base na hipótese de que este modelo, utilizando-se galpões climatizados, como sugerido pelos autores, possa ser usado em condições brasileiras. O modelo se mostrou adequado para o objetivo previsto, na forma indicada por Gates et al. (1995) para galpões com vazão mássica do ar elevada, (120,8 kg de ar por segundo ou maior). É necessário um fator de correção referente a uma série de fontes de calor desprezada pelo modelo para galpões sem uma grande vazão mássica, ou a inclusão dessas fontes

The RNA-binding protein, ZFP36L2, influences ovulation and oocyte maturation

ZFP36L2 protein destabilizes AU-rich element-containing transcripts and has been implicated in female fertility. In the C57BL/6NTac mouse, a mutation in Zfp36l2 that results in the decreased expression of a form of ZFP36L2 in which the 29 N-terminal amino acid residues have been deleted, ΔN-ZFP36L2, leads to fertilized eggs that arrest at the two-cell stage. Interestingly, homozygous ΔN-Zfp36l2 females in the C57BL/6NTac strain release 40% fewer eggs than the WT littermates (Ramos et al., 2004), suggesting an additional defect in ovulation and/or oocyte maturation. Curiously, the same ΔN-Zfp36l2 mutation into the SV129 strain resulted in anovulation, prompting us to investigate a potential problem in ovulation and oocyte maturation. Remarkably, only 20% of ΔN-Zfp36l2 oocytes in the 129S6/SvEvTac strain matured ex vivo, suggesting a defect on the oocyte meiotic maturation process. Treatment of ΔN-Zfp36l2 oocytes with a PKA inhibitor partially rescued the meiotic arrested oocytes. Furthermore, cAMP levels were increased in ΔN-Zfp36l2 oocytes, linking the cAMP/PKA pathway and ΔN-Zfp36l2 with meiotic arrest. Since ovulation and oocyte maturation are both triggered by LHR signaling, the downstream pathway was investigated. Adenylyl cyclase activity was increased in ΔN-Zfp36l2 ovaries only upon LH stimulation. Moreover, we discovered that ZFP36L2 interacts with the 3′UTR of LHR mRNA and that decreased expression levels of Zfp36l2 correlates with higher levels of LHR mRNA in synchronized ovaries. Furthermore, overexpression of ZFP36L2 decreases the endogenous expression of LHR mRNA in a cell line. Therefore, we propose that lack of the physiological down regulation of LHR mRNA levels by ZFP36L2 in the ovaries is associated with anovulation and oocyte meiotic arrest.Fil: Ball, Christopher B.. University of North Carolina; Estados UnidosFil: Rodriguez, Karina F.. National Institutes of Health; Estados UnidosFil: Stumpo, Deborah J.. National Institutes of Health; Estados UnidosFil: Ribeiro Neto, Fernando. National Institutes of Health; Estados UnidosFil: Korach, Kenneth S.. National Institutes of Health; Estados UnidosFil: Blackshear, Perry J.. University of Duke; Estados Unidos. National Institutes of Health; Estados UnidosFil: Birnbaumer, Lutz. National Institutes of Health; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ramos, Silvia B. V.. University of North Carolina; Estados Unido

Bot’n roll robotic kit as a learning tool for youngsters

Activities involving robotics, projecting assembling and programming robots are in essence hands-on and inquiry-based activities leading to an effective learning of different aspects of science and technology among others. Different approaches have being used to introduce robotics in the education of young children. In this communication we will present an approach that in an inquiry based science education, IBSE, perspective, uses an informal environment to introduced robotics, as well as a range of other science and technology, concepts and competencies to young students. Many youngsters are getting interested on general technology and the robotics field in particular. Even though their knowledge is very basic they are very enthusiastic and willing to learn quickly. Most robotics events consist of competitions, and that means the youngsters still need guidance by professionals. RoboParty is a different educational robotics event that teaches the participants, with IBSE hands-on techniques, how to build a robot from scratch to program it and in the end they keep the robot they built for themselves for further exploration. Such robot to be built by the young children for the first time needs to be very easy and with a friendly programming language. The Bot’n Roll robotics kit was developed specifically for the RoboParty event, and has since then been improved with more sensors and actuators, which are simple to built and easy to use. The Bot’n Roll robot family launched recently another more complex robot that uses omnidirectional wheels and that can be used on other robotic competitions like world known RoboCup. This paper describes also the Bot’n Roll robots and show how they are built, bearing in mind that these robots were developed for youngsters who never worked with robotics