Studying the thermal conductivity of a deep Eocene clay formation: direct measurements vs back-analysis results

An experimental study on Ypresian clays–one of the potential deep and sedimentary clay formations in Belgium for the geological disposal of heat-emitting radioactive waste–has been undertaken to systematically study its thermal conductivity using different experimental techniques. As a first step, a new experimental setup with heat flux measurement has been used and careful pre-conditioning protocols have been followed to directly measure this thermal property. The aim of these pre-conditioning tests has been ensuring a very high degree of saturation and the closure of fissures / gaps along bedding planes before the thermal tests are run under low stress conditions. Thermal tests have shown to be particularly sensitive when the thermal conductivity is determined along a direction orthogonal to these bedding planes. The study is then complemented by using a constant volume heating cell, in which heating pulse tests have been carried out under fully saturated conditions that have been ensured with a high water back-pressure. Numerical models have been used to interpret this pulse test, to exploit all the information provided by temperature measurements and to back-analyse the thermal conductivity. Direct thermal conductivity data with the improved pre-conditioning protocol allowed obtaining results consistent with the values reported when using back-analysis in the constant volume cell. The article discusses the importance of restoring full saturation conditions, particularly on retrieval of deep sedimentary clays, which may undergo opening of fissures along bedding planes that may affect the correct determination of the thermal conductivity.Peer ReviewedPostprint (author's final draft

Law of large numbers for certain cylinder flows

We construct new examples of cylinder flows, given by skew product extensions of irrational rotations on the circle, that are ergodic and rationally ergodic along a subsequence of iterates. In particular, they exhibit law of large numbers. This is accomplished by explicitly calculating, for a subsequence of iterates, the number of visits to zero, and it is shown that such number has a gaussian distribution.Comment: 25 pages, referee suggestions incorporated, to appear in Ergodic Theory and Dynamical System

Robot Formations Control Using Fast Marching

This paper presents the application of the Voronoi Fast Marching (V FM) method to the Control of Robot Formations. The V FM method uses the propagation of a wave (Fast Marching) operating on the world model to de- termine a motion plan over a viscosity map (similar to the refraction index in optics) extracted from the updated map model. The computational effciency of the method allows the planner to operate at high rate sensor frequencies. This method allows us to maintain good response time and smooth and safe planned trajectories. The navigation function can be classiffed as a type of potential field, but it has no local minima, it is complete (it finds the solu- tion path if it exists) and it has a complexity of order n (O(n)), where n is the number of cells in the environment map. The results presented in this paper show how the proposed method behaves with mobile robot formations and generates trajectories of good quality without problems of local minima when the formation encounters non-convex obstacles

Water retention properties of two deep Tertiary clay formations within the context of radioactive waste disposal.

Belgium investigates the design for disposal of its ‘High-Level Radioactive Waste’ in two deep clay formations; the Boom clay at Mol, considered the reference host formation, and Ypresian clay at Kallo as the alternative one. The water retention properties of these deep low-porosity formations have been investigated for two main reasons. High suctions develop as a consequence of sample retrieval (at depths between 223 and 350 m), which affect the hydro-mechanical response of these materials, especially at low stress levels. In addition, water retention properties have also been studied to better assess possible desaturation effects due to venting of the disposal facility galleries. After a description of their main properties at intact state and their microstructural features (pore size distributions), the water retention properties of both clays covering a wide suction range and using different complementary techniques are presented and discussed.Peer ReviewedPostprint (published version

Robot formation motion planning using Fast Marching

This paper presents the application of the Voronoi Fast Marching (VFM) method to path planning of mobile formation robots. The VFM method uses the propagation of a wave (Fast Marching) operating on the world model to determine a motion plan over a viscosity map (similar to the refraction index in optics) extracted from the updated map model. The computational efficiency of the method allows the planner to operate at high rate sensor frequencies. This method allows us to maintain good response time and smooth and safe planned trajectories. The navigation function can be classified as a type of potential field, but it has no local minima, it is complete (it finds the solution path if it exists) and it has a complexity of order n(O(n)), where n is the number of cells in the environment map. The results presented in this paper show how the proposed method behaves with mobile robot formations and generates trajectories of good quality without problems of local minima when the formation encounters non-convex obstacles.This work has been supported by the CAM Project S2009/DPI-1559/ROBOCITY2030 II, developed by the research team RoboticsLab at the University Carlos III of Madrid.Publicad

Industrias y evaluación de impacto ambiental: Análisis del proceso de revisión inicial en Argentina

The approach of “pollute first, then clean up”, has been understood to be hard both technologically and economically. Therefore, the necessity of adopting another strategy, which is anticipate-and-prevent, has risen and consequently the environmental impact assessment (EIA) has emerged as a tool. Screening is one of the earliest steps of every EIA process and it is characterized as the determination of whether or not an environmental assessment must be prepared for a particular project. The aim of this paper is to identify, analyse and compare the methodological models regulating the screening process of industrial activity in Argentina, a federal country without a national directive concerning this particular matter and where each of the 24 districts are autonomous in this matter. This research was followed through employing a comparative method, which was implemented based on secondary data analysis. Three guiding questions and three criteria were used to compare the 24 districts. Six different screening process models were described (both qualitative and quantitative). The six chosen models were integrated into three great groups. The group of districts that present “Preliminary study” + “Case by case” approaches prevail, while in second place comes the “Threshold” + “Case by case” approaches. Finally, the more complete screening model, with specific legislation for EIA in industries and a quantitative environmental complexity index, turned out to be the least applied in Argentina.El enfoque de “contaminar, luego limpiar”, se considerada desde hace años inapropiado tanto en términos tecnológicos y económicos; así, la necesidad de adoptar otra estrategia, como “anticipar y prevenir” ha tomado mayor importancia y para ello surge como herramienta la evaluación de impacto ambiental (EIA). El screening es uno de los pasos iniciales de la EIA y es un proceso para determinar si un proyecto en particular debe presentar un estudio ambiental. El objetivo de este artículo es identificar, analizar y comparar los modelos metodológicos que regulan el proceso de revisión inicial para la actividad industrial en Argentina, un país federal sin una directiva nacional al respecto y donde cada uno de los 24 distritos son autónomos en este sentido. Se utilizó el método comparativo, implementado con base en datos secundarios. Se utilizaron tres preguntas guía y tres criterios para comparar los 24 distritos. Se distinguieron seis modelos de screening (tanto cualitativos como cuantitativos), los cuales se integraron finalmente en tres grandes grupos. El grupo que comprende “Estudio preliminar” + “Análisis caso por caso” es el que prevalece, siguiéndole el de “Umbrales” + “Análisis caso por caso”. Finalmente, el modelo de screening más completo, con legislación específica para industrias y un índice cuantitativo de complejidad ambiental, resulta ser el menos aplicado en Argentina.Fil: Barilari, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; ArgentinaFil: Massone, Hector Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; ArgentinaFil: Lima, María Lourdes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; ArgentinaFil: Mantecón, Cecilia Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentin

Cavity Length Affects the Occupation of Trap-Nests by Centris analis and Tetrapedia diversipes (Hymenoptera: Apidae)

The ideal cavity dimensions for neotropical cavity-nesting bees with the potential to be managed as pollinators have not been getting proper attention. We investigated whether the occupancy of trap-nests by Centris analis Fabricius and Tetrapedia diversipes Klug, and other nesting aspects, are affected by different trap-nest length. The used trap-nests were cardboard tubes 5, 10, 15 and 20 cm in length, and Ø 8 mm. Occupation rates of 10-cm trap-nests by C. analis was higher than that of the 5-cm ones (χ2=11.17, gl=1, p<0.001). On the other hand, there was not difference between the occupation rates of 10 and 15-cm long trap-nests (χ2=0.51, gl=1, p=0.48), and between the ones measuring 15 and 20 cm long (χ2=1.36, gl=1, p=0.24). T. diversipes occupied a smaller number of 5-cm trap-nests than the 10-cm ones (χ2=1.52, gl=1, p=0.22), as well as that the 15-cm ones were more occupied than the 10-cm trap-nests (χ2=4.23, gl=1, p=0.04); moreover, there was not difference between the occupation of 15 and 20-cm trap-nests (χ2=0.28, gl=1, p=0.59). Both species showed higher rates of dead immatures in nests set in the shortest trap-nests, whereas these mortality rates were lower in the longest ones. By taking into consideration that there was not significant difference in many of the assessed parameters in comparison to values recorded for 15 and 20-cm long trap-nests, it seems likely to recommend the adoption of 10-cm long trap-nests for C. analis reproduction in agricultural sites that depend on the pollination service provided by this bees species

Interaction of Refractory Dibenzothiophenes and Polymerizable Structures

We carried out first principles calculations to show that polymerizable structures containing hydroxyl (alcoholic chain) and amino groups are suitable to form stable complexes with dibenzothiophene (DBT) and its alkyl derivates. These sulfur pollutants are very difficult to eliminate through traditional catalytic processes. Spontaneous and exothermic interactions at 0 K primarily occur through the formation of stable complexes of organosulfur molecules with monomeric structures by hydrogen bonds. The bonds are formed between the sulfur atom and the hydrogen of the hydroxyl group; additional hydrogen bonds are formed between the hydrogen atoms of the organosulfur molecule and the nitrogen atoms of the monomers. We vary the number of methylene groups in the alcoholic chain containing the hydroxyl group of the monomer and find that the monomeric structure with four methylene groups has the best selectivity towards the interaction with the methyl derivates with reference to the interaction with DBT. Even this study does not consider solvent and competitive adsorption effects; our results show that monomeric structures containing amino and hydroxyl groups can be used to develop adsorbents to eliminate organosulfur pollutants from oil and its derivates

La incorporación política del Soconusco a la República mexicana: una historia multifactorial (1824-1842)

One of the gaps in the historiography of Chiapas is the incorporation of the Soconusco region into Mexico. Although the province of Chiapas became definitely integrated into Mexico in 1824, from that date to 1842, one of the regions it is currently constituted by remained «politically neutral». This paper seeks to provide an initial general approach to various factors that made it possible to integrate the Soconusco region into the Mexican Republic. It explains the incorporation of this region as a process that was gradually constructed over seventeen years firstly due to Lucas Alamán’s diplomatic skill, the Soconusco clergy’s political bonds and private interests, the internal situation of the region’s municipalities, and the political development unfolding in Mexico and Central AmericaUna de las lagunas de la historiografía chiapaneca es la relacionada al proceso de incorporación del Soconusco a México; si bien la provincia de Chiapas se integró definitivamente al país en 1824, una de las regiones que hoy la conforman permaneció en «neutralidad política» de 1824 a 1842. De ahí que el objetivo de este artículo sea proporcionar una primera aproximación general a los diversos factores que posibilitaron la integración de esta región a la República mexicana. Este trabajo explica esta incorporación como un proceso que se fue construyendo a lo largo de 17 años, gracias, en primera instancia, a las habilidades diplomáticas de Lucas Alamán, y también a los vínculos políticos e intereses particulares del clero soconusquense, a la situación interna de los ayuntamientos de la zona y al desenvolvimiento político de México y Centroaméric