Chaotic Vibrations in a Buckled Beam Induced by a Galloping Phenomenon

Chaos theory has spectacularly evolved since the pioneering work by E. Lorenz on chaotic motion in a simple, deterministic system. Since then, the chaotic behavior of many other deterministic, low-dimensional systems in a large variety of fields has been developed. In the particular field of aeroelasticity of aircraft structures several reports of chaos have been documented. However, we are unaware of any report of chaotic systems of civil (non-aeronautical) use induced by an aeroelastic phenomenon. In this paper a well defined civil, aeroelastic system, susceptible to exhibit chaotic behavior is presented. The system consists of a buckled beam from which a second beam is suspended. This last beam (hereafter, galloping beam) has a square cross- section and can undergo transverse galloping. The system is subjected to an uniform wind flow and, as it will be shown in the paper, for wind velocities larger than a threshold value, the galloping beam begins to oscillate and induces, for a determined set of parameter values, a chaotic motion in the buckled bea

Rumble: Data Independence for Large Messy Data Sets

This paper introduces Rumble, an engine that executes JSONiq queries on large, heterogeneous and nested collections of JSON objects, leveraging the parallel capabilities of Spark so as to provide a high degree of data independence. The design is based on two key insights: (i) how to map JSONiq expressions to Spark transformations on RDDs and (ii) how to map JSONiq FLWOR clauses to Spark SQL on DataFrames. We have developed a working implementation of these mappings showing that JSONiq can efficiently run on Spark to query billions of objects into, at least, the TB range. The JSONiq code is concise in comparison to Spark's host languages while seamlessly supporting the nested, heterogeneous data sets that Spark SQL does not. The ability to process this kind of input, commonly found, is paramount for data cleaning and curation. The experimental analysis indicates that there is no excessive performance loss, occasionally even a gain, over Spark SQL for structured data, and a performance gain over PySpark. This demonstrates that a language such as JSONiq is a simple and viable approach to large-scale querying of denormalized, heterogeneous, arborescent data sets, in the same way as SQL can be leveraged for structured data sets. The results also illustrate that Codd's concept of data independence makes as much sense for heterogeneous, nested data sets as it does on highly structured tables.Comment: Preprint, 9 page

Rheological and composition analyses of CO2 gas hydrates

In the present work, it is investigated the rheological behavior of CO2 hydrates form from water-in-oil emulsions since high concentrations of this gas have been reported in the Brazilian Pre-salt oil wells, with large potential to form hydrates. To investigate this fact, a sequence of tests was conducted using an assembly composed by a rheometer, a magnetic pressure cell, and a high-pressure system, where similar pressure and temperature conditions were applied to those found in the petroleum industry. The novel results displayed in curves of viscosity over time are revealed in two main sections. Firstly, it is shown the effect produced by the shear rate, water volume fraction and salt impact on CO2 hydrates. It is also investigated the ability of the reconstruction of the CO2 hydrates and its memory effect. Secondly, results that indicate the effect produced on the induction time of hydrate formation by the addition of gas condensate and by the addition of small amounts of powder asphaltenes in the water-in-oil emulsions are shown. These interfacially active particles seem to act like kinetic hydrate inhibitors.No presente trabalho é pesquisado o comportamento reológico dos hidratos de CO2 formados a partir de emulsões de água em óleo, pois grandes concentrações deste gás foram reportados nos poços de petróleo do Pré-sal brasileiro, com grande potencial para formar hidratos. Para investigar este fato, realizou-se uma sequência de testes utilizando uma montagem composta por um reômetro, uma célula de pressão magnética e um sistema de alta pressão, onde foram aplicadas condições de pressão e temperatura similares às encontradas na indústria do petróleo. Os resultados inéditos exibidos em curvas de viscosidade ao longo do tempo são expostos em duas seções principais. Primeiramente, é mostrado o efeito produzido pela taxa de cisalhamento, a fração de volume da água e o impacto do sal nos hidratos de CO2. Também, é investigado a capacidade de reconstrução dos hidratos de CO2 e seu efeito de memória. Em segundo lugar, são mostrados alguns resultados que indicam o efeito produzido no tempo de indução da formação de hidratos pela adição de gás condensado e pela adição de pequenas quantidades de asfaltenos em pó nas emulsões de água em óleo. Parece ser que essas partículas ativas interfacialmente atuam como inibidores cinéticos de hidratos

Selection for high spike fertility index increases genetic progress in grain yield and stability in bread wheat

Spike fertility index (SF) has been proposed as a promising trait to be used as a selection criterion in wheat breeding programs aimed at increasing grain yield, but no actual evidence of its successful application has been reported. In this study, 146 recombinant inbred lines derived from a cross between ‘Baguette 10’ and ‘Klein Chajá’, Argentinean spring bread wheat cultivars with contrasting SF, were evaluated during three crop seasons (2013, 2014 and 2015) at Balcarce, Argentina. Grain yield, grain number/m2, grain weight, and SF were measured at maturity. Changes in grain yield (i.e., responses to selection) after application of different selection strategies, including different selection criteria and selection intensities, were determined. Significant correlations were observed between grain number and grain yield, SF and grain yield, and SF and grain weight. Analysis of SF variance components showed a significant genotype × environment interaction, but it represented only 9% of the total variation, whereas 51% of the variation was genetic, resulting in a high narrow-sense heritability (0.84). The use of SF as a selection criterion, either solely or in combination with selection for high yield, increased yield, resulting in higher and more stable yields than if selecting for high yield alone. Our findings support the use of spike fertility index as a selection criterion for increasing genetic progress and stability of yield in bread wheat breeding programs.Fil: Alonso, María Pía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Mirabella, Nadia Estefania. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Panelo, Juan Sebastián. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Cendoya, Marcelo Gustavo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Pontaroli, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

The trail of American domestic engineers in European social housing

El presente artículo analiza la gran influencia que los Manuales escritos por las norteamericanas Catharine Beecher, Christine Frederick y Lillian Gilbreth tuvieron sobre la concepción de la domesticidad en los programas residenciales de la Nueva Oficina de Construcción de Frankfurt, liderada por Ernst May entre 1925 y 1930, en la que Margarete Schütte-Lihotzky se encargó del estudio de los hábitos de vida. Desde posiciones muy diversas, como la intelectualidad de Beecher, el pragmatismo de Frederick y el cientifismo de Gilbreth, todas ellas tipificaron, hicieron eficiente y optimizaron, respectivamente, la concepción proyectual y productiva de la vivienda. Esto implicaba racionalizar, modernizar y mecanizar su contenido con el fin de mejorar el trabajo del ama de casa. En sus textos, no se cuestiona si el lugar apropiado para la mujer es el hogar, sino que se afirma que no está bien ideado. Por primera vez, la casa es pensada desde un nuevo punto de vista: el del usuario. A través del artículo se revelan, desde un punto de vista no planteado anteriormente, algunos de los posibles medios de transmisión de las investigaciones americanas al contexto europeo.This article analyzes the great influence that the Manuals written by Catharine Beecher, Christine Frederick and Lillian Gilbreth had in the conception of domesticity in the residential programs carried out by the New Frankfurt initiative led by Ernst May between 1925 and 1930, in which Margarete Schütte-Lihotzky was in charge of studying life habits. From their different stances, Beecher’s intellectualism, Frederick’s pragmatism and Gilberth’s scientism, they all typified, made more efficient and optimized, respectively, the design and productive conception of the house. This meant rationalizing, modernizing and mechanizing its content with the aim of improving the work conditions of the housewife. Their texts do not question whether the home is the adequate place for women, they just state that its spaces are not correctly thought out. For the very first time, the house was conceived from a new perspective: that of the user. This article reveals, from a novel point of view, some of the possible means by which the research carried out by these American women reached the European context

Proposal of a three level complexity model for office automation

Office automation is one of the fields where the complexity related with technologies and working environments can be best shown. This is the starting point we have chosen to build up a theoretical model that shows us a scene quite different from the one traditionally considered. Through the development of the model, the levels of complexity associated with office automation and office environments have been identified, establishing a relationship between them. Thus, the model allows to state a general principle for sociotechnical design of office automation systems, comprising the ontological distinctions needed to properly evaluate each particular technology and its virtual contribution to office automation. From this fact comes the model's taxonomic ability to draw a global perspective of the state-of-art in office automation technologies