Fatigue crack behaviour: comparing three-point bend test and wedge splitting test data on vibrated concrete using Paris' law

The fatigue behaviour of concrete has become more important for the design of constructions due to the desire to build slimmer structures, which are more sensitive to fatigue loading. This article aims to evaluate and compare the fatigue crack propagation rate in vibrated concrete for four different stress ratios using the Paris-Erdogan law. The data evaluation in this article is based on crack mouth opening displacement (CMOD) measurements from cyclic three-point bending tests on single edge notched beams and from wedge splitting tests on notched cubes, obtained from experiments at Ghent University. For this study, finite element analysis is used to obtain a mathematical relationship between the CMOD and the relative crack length a/W, as well as a relationship between the stress intensity ratio ?K and a/W. The obtained mathematical relationships were then combined with the measured CMOD values to correlate the test data to the Paris- Erdogan law. Herein, the crack propagation rate da/dN is plotted against the corresponding stress intensity range ?K in a log-log graph. In a final step, the Paris-Erdogan law parameters C and m were obtained through linear curve fitting on the data points from the obtained graphs. The parameters C and m are then used to compare and evaluate the fatigue crack behavior in vibrated concrete, and the differences between the results from the three-point bend tests and wedge splitting tests

The <i>Castalia</i> mission to Main Belt Comet 133P/Elst-Pizarro

We describe Castalia, a proposed mission to rendezvous with a Main Belt Comet (MBC), 133P/Elst-Pizarro. MBCs are a recently discovered population of apparently icy bodies within the main asteroid belt between Mars and Jupiter, which may represent the remnants of the population which supplied the early Earth with water. Castalia will perform the first exploration of this population by characterising 133P in detail, solving the puzzle of the MBC’s activity, and making the first in situ measurements of water in the asteroid belt. In many ways a successor to ESA’s highly successful Rosetta mission, Castalia will allow direct comparison between very different classes of comet, including measuring critical isotope ratios, plasma and dust properties. It will also feature the first radar system to visit a minor body, mapping the ice in the interior. Castalia was proposed, in slightly different versions, to the ESA M4 and M5 calls within the Cosmic Vision programme. We describe the science motivation for the mission, the measurements required to achieve the scientific goals, and the proposed instrument payload and spacecraft to achieve these

Combined Methylome, Transcriptome and Proteome Analyses Document Rapid Acclimatization of a Bacterium to Environmental Changes

Polynucleobacter asymbioticusstrain QLW-P1DMWA-1(T)represents a group of highly successful heterotrophic ultramicrobacteria that is frequently very abundant (up to 70% of total bacterioplankton) in freshwater habitats across all seven continents. This strain was originally isolated from a shallow Alpine pond characterized by rapid changes in water temperature and elevated UV radiation due to its location at an altitude of 1300 m. To elucidate the strain's adjustment to fluctuating environmental conditions, we recorded changes occurring in its transcriptomic and proteomic profiles under contrasting experimental conditions by simulating thermal conditions in winter and summer as well as high UV irradiation. To analyze the potential connection between gene expression and regulation via methyl group modification of the genome, we also analyzed its methylome. The methylation pattern differed between the three treatments, pointing to its potential role in differential gene expression. An adaptive process due to evolutionary pressure in the genus was deduced by calculating the ratios of non-synonymous to synonymous substitution rates for 20 Polynucleobacterspp. genomes obtained from geographically diverse isolates. The results indicate purifying selection

Metabolomic Alterations Do Not Induce Metabolic Burden in the Industrial Yeast M2n[pBKD2-Pccbgl1]-C1 Engineered by Multiple \u3b4-Integration of a Fungal \u3b2-Glucosidase Gene

In the lignocellulosic yeast development, metabolic burden relates to redirection of resources from regular cellular activities toward the needs created by recombinant protein production. As a result, growth parameters may be greatly affected. Noteworthy, Saccharomyces cerevisiae M2n[pBKD2-Pccbgl1]-C1, previously developed by multiple d-integration of the b-glucosidase BGL3, did not show any detectable metabolic burden. This work aims to test the hypothesis that the metabolic burden and the metabolomic perturbation induced by the d-integration of a yeast strain, could differ significantly. The engineered strain was evaluated in terms of metabolic performances and metabolomic alterations in different conditions typical of the bioethanol industry. Results indicate that the multiple d-integration did not affect the ability of the engineered strain to grow on different carbon sources and to tolerate increasing concentrations of ethanol and inhibitory compounds. Conversely, metabolomic profiles were significantly altered both under growing and stressing conditions, indicating a large extent of metabolic reshuffling involved in the maintenance of the metabolic homeostasis. Considering that four copies of BGL3 gene have been integrated without affecting any parental genes or promoter sequences, deeper studies are needed to unveil the mechanisms implied in these metabolomic changes, thus supporting the optimization of protein production in engineered strains

Guia metodológico para uso do Laser Scanner Terrestre (TLS) em ambiente florestal.

A reconstituição dos ambientes florestais por meio de varreduras Laser Scanner Terrestre (TLS) tem possibilitado, além da compreensão desses ambientes com a extração de variáveis qualitativas que podem ser usadas em levantamentos fitossociológicos, aplicações de caráter métrico, como é o caso da extração de variáveis dendrométricas e contagem de indivíduos. Sem dúvida, essa tecnologia tem ganhado espaço no meio florestal e, possivelmente, em poucos anos, passará a fazer parte dos protocolos de inventários florestais. O planejamento do levantamento de campo com o TLS é uma das etapas fundamentais na coleta de dados, tendo em vista que está diretamente relacionado à qualidade do produto final. Além disso, facilita etapas como o registro da nuvem de pontos, processamento e posterior obtenção de variáveis dendrométricas.bitstream/item/222740/1/CT-467-1897-final.pd

Câmeras modificadas e multiespectrais embarcadas em drones: enfoque para estudos da vegetação.

Nos últimos dez anos, os drones vêm sendo cada vez mais utilizados para aplicações florestais devido à sua flexibilidade, autonomia e capacidade de obter dados, de maneira remota, por meio de sensores embarcados. Essa ferramenta pode ser usada em substituição de algumas atividades de coleta de dados normalmente trabalhosas, demoradas, sujeitas a erro e de alto custo. Podem contribuindo, dessa maneira, para gerar informações decisivas para a gestão e a tomada de decisão na atividade florestal, com elevada precisão e custos reduzidos. Câmeras multiespectrais embarcadas em drones ampliam a capacidade de análise nos estudos de florestas plantadas e nativas, auxiliando na análise do desenvolvimento e da vitalidade dos plantios ou florestas e identificando fatores prejudiciais relacionados com estresses bióticos e abióticos. Entretanto, apesar dos avanços tecnológicos atingidos até o momento, a captura de dados de qualidade ainda permanece um grande desafio. Nesta publicação são apresentadas diretrizes orientadoras para o desenvolvimento de trabalhos sobre vegetação que envolvem a coleta de imagens por meio de câmeras multiespectrais, e modificadas, embarcadas em drones

Seven psychosocial principles to explain terrorism

Este artículo describe las bases para una aproximación psicosocial al análisis de los fenómenos terroristas. Más concretamente, se exponen siete principios explicativos del terrorismo que sean congruentes con los supuestos metateóricos y el cuerpo de conocimientos propios de la Psicología social. Desde esta óptica el terrorismo se concibe como una estrategia de influencia sociopolítica. Los atributos psicológicos de los terroristas son analizados por su relación con diversos procesos de influencia social. También se destaca la importancia de los factores ideológicos. Por último, se presta una atención muy especial a las semejanzas entre las organizaciones terroristas y los movimientos sociales ordinarios y a la estructura y dinámicas grupales propias de aquellas organizacionesResearch approaches leading to the understanding of the terrorist phenomenon are suggested. Seven principles explaining terrorism are analysed from a psychosocial approach: They could complete the explanations of terrorism focused in socio-structural and psychological variables, the latter being insufficient and often erroneous. Thus, terrorism is presented as a strategy of political influence, and the psychological attributes of terrorists are explained as the result of several influential social processes. We considered that terrorist attacks and campaigns correspond to strategic reasons, but we also assume that the rationality of the terrorists perspective is limited. As far as the organisational parameters are concerned, we propose an analogy with ordinary social movements, especially relating to their ideological frameworks of legitimisation and resource mobilization processesS

Correlations between dendrometric and allometric variables of Eucalyptus benthamii under agroforestry systems in the subtropic of Brazil

ABSTRACT: The growing interest in integrated agricultural production systems has increased the search for information about the arboreal component, thus, information about the correlations and associations between dendrometric and allometric variables are important. This study investigated the results obtained through simple correlation analysis and its breakdown via path analysis of dendrometric and allometric variables of Eucalyptus benthamii under different integrated systems and monoculture. The following variables were evaluated: diameter at 1.3 m above ground, total height, volume with and without bark, crown radius and biomass components stem wood and bark, branches, leaves and total aboveground biomass. Descriptive statistics showed the great variance of the data with coefficients of variation from 18 to 85.08%. All correlations (Spearman) between allometric and dendrometric variables were positive and 89% were statistically significant (p < 0.05). For the total aboveground biomass as dependent variable, the variables with the greatest direct effects were wood biomass (0.26), volume with bark (0.17) and branch biomass (0.15). With the results of the simple correlation any variable can be used in the modeling of the total aboveground biomass. However, the path analysis makes it clear that some variables have weak associations even with significant correlations of great magnitude. RESUMO: O crescente interesse por sistemas integrados de produção agrícola tem aumentado a busca por informações sobre o componente arbóreo, portanto, informações sobre as correlações e associações entre variáveis dendrométricas e alométricas são importantes. Este estudo investigou os resultados obtidos por meio de análises de correlação simples e sua decomposição por meio de análise de trilha de variáveis dendrométricas e alométricas de Eucalyptus benthamii sob diferentes sistemas integrados e monocultivos. Foram avaliadas as seguintes variáveis: diâmetro a 1,3 m acima do solo, altura total, volume com e sem casca, raio da copa e componentes da biomassa madeira e casca do caule, galhos, folhas e biomassa aérea total. A estatística descritiva mostrou grande variância dos dados com coeficientes de variação de 18 a 85,08%. Todas as correlações (Spearman) entre as variáveis alométricas e dendrométricas foram positivas e 89% foram estatisticamente significativas (p <0,05). Para a biomassa total acima do solo como variável dependente, as variáveis com maiores efeitos diretos foram biomassa de madeira (0,26), volume com casca (0,17) e biomassa de ramos (0,15). Com os resultados da correlação simples, qualquer variável pode ser usada na modelagem da biomassa total acima do solo. No entanto, a análise do caminho deixa claro que algumas variáveis apresentam associações fracas mesmo com correlações significativas de grande magnitude