Evaluation of the mechanical properties of self compacting concrete using current estimating models. Estimating the modulus of elasticity, tensile strength, and modulus of rupture of self compacting concrete

This study includes an analysis of the applicability of current models used for estimating the mechanical properties of conventional concrete to self-compacting concrete. The mechanical properties evaluated are: modulus of elasticity, tensile strength, and modulus of rupture. An extensive database which included the dosifications and the mechanical properties of 627 mixtures from 138 different references, was used. The models considered are: ACI, EC-2, NZS 3101:2006 (New Zealand code) and the CSA A23.3-04 (Canadian code). The precision in estimating the modulus of elasticity and tensile strength is acceptable for all models; however, all models are less precise in estimating the modulus of rupture

Albumin, the responsible protein of the Cu2+-dependent hydrolysis of O-hexyl O-2,5-dichlorophenyl phosphoramidate (HDCP) by chicken serum "antagonistic stereoselectivity"

O-hexyl O-2,5-dichlorophenyl phosphoramidate (HDCP) is a chiral analogous compound of the methamidophos insecticide that induces delayed neuropathy, and the R-(+)-HDCP enantiomer is an inhibitor of neuropathy target esterase (NTE). This enantiomer is not hydrolized by Ca2+-dependent phosphotriesterases in mammal tissues. Our group had reported R-(+)-HDCP hydrolysis in chicken serum enhanced by 30–250 μM copper in ex vivo assays, which we call "antagonistic stereoselectivity". We checked the hypothesis of the role of cupper binding proteins. Two hundred micrograms of human serum ceruloplasmine or horse kidney methallotionein in 1 mL containing 400 μM HDCP for 60 min showed no significant Cu2+-dependent hydrolysis. However under the same conditions, 10 μL of chicken serum or 10 μL of buffer containing 216 μg of chicken serum albumin (CSA) (amount of albumin content in this serum volume) with 100 μM Cu2+ showed the same stereoselectivity and similar levels to the Cu2+-dependent R-(+)-HDCP hydrolysis. About 75% of R-(+)-HDCP were hydrolyzed after 120 min in the presence of 100 μM Cu2+ (inhibited by 5 mM EDTA). No effects was observed by divalent cations Cu2+, Zn2+, Fe2+, Ca2+, Mn2+ and Mg2+. These results confirm that albumin is the protein responsible for "antagonistic stereoselectivity" observed in chicken ser

Nash Solution as a Multi-Criteria Decision Making Technique for Control Problems

[Abstract] A control system problem can be viewed as a multiobjective problem due to the fact that there are many requirements to be satisfied. Nowadays, multi-objective optimization deals with this kind of problem by implementing optimization techniques, capable of searching for the Pareto set approximation, hereafter the designer needs to select the best solution that provides a good trade-off among the competitve objectives from the Pareto front approximation. Therefore, in this communication we address the problem of selecting the best trade-off between the conflictive objectives, this stage is called the Multi-Criteria Decision Making (MCDM). In this paper we propose to use the Nash solution as a tuning technique to select the design alternative to implement on the control system. This selection is compared with others Proportional-Integral (PI) tuning rules on the literature.This work has received financial support from the Spanish Ministry of Economy and Competitiveness program under grant DPI2013-47825-C3-1-R. The financial support from the University of Costa Rica, under the grants 322-B4-218 and 731-B4-213, is greatly appreciatedUniversidad de Costa Rica; 322-B4-218Universidad de Costa Rica; 731-B4-213https://doi.org/10.17979/spudc.978849749808

Estudio sobre la resistencia y las propiedades mecánicas del hormigón autocompactante

En este trabajo se ha creado una extensa base de datos que incluye las dosificaciones y los resultados experimentales de las características mecánicas del hormigón autocompactante (HAC), lo cual ha permitido analizar de forma generalizada la influencia de varias variables en la resistencia a compresión del HAC. Las variables analizadas incluyen la influencia dei contenido y tipo de filler, la relación agua/cemento, y ia influencia deí contenido de áridos. También se ha evaluado la aplicabiiidad de los modelos de las normativas para estimar las características mecánicas dei HAC

Mechanical properties of self-consolidating concrete using conventional concrete models

The objective of this study is to analyze the applicability of current models used for estimating the mechanical properties of conventional concrete to self-consolidating concrete (SCC). The mechanical properties evaluated are modulus of elasticity, tensile strength,and modulus of rupture. As part of the study, it was necessary to build an extensive database that included the proportions and mechanical properties of 627 mixtures from 138 different references. The same models that are currently used for calculating the mechanical properties of conventional concrete were applied to SCC to evaluate their applicability to this type of concrete. The models considered are the ACI 318, ACI 363R, and EC2. These are the most commonly used models worldwide. In the first part of the study, the overall behavior and adaptability of the different models to SCC is evaluated. The specific characterization parameters for each concrete mixture are used to calculate the various mechanical properties applying the different estimation models. The second part of the analysis consists of comparing the experimental results of all the mixtures included in the database with the estimated results to evaluate the applicability of these models to SCC. Various statistical procedures, such as regression analysis and residual analysis, are used to compare the predicted and measured properties. It terms of general applicability, the evaluated models are suitable for estimating the modulus of elasticity, tensile strength, and modulus of rupture of SCC. These models have a rather low sensitivity, however, and adjust well only to mean values. This is because the models use the compressive strength as the main variable to characterize the concrete and do not consider other variables that affect these properties

Aplicación del algoritmo de Kalman al estudio de la ritmicidad ultradiana en el comportamiento expontáneo de sujetos humanos aislados

Este trabajo explora la posible existencia de ritmos ultradianos (período comprendido entre 30 minutos y 20 horas) en el comportamiento espontáneo vigil del hombre, analizando espectralmente las señales con el filtra do adaptativo de Kalman. En cuatro sujetos, cada uno de los cuales permaneció aislado en una habitación, se registraron los siguientes comportamientos: deambulación. exploración, autocontacto y alimentación. De forma simultánea se contabilizó la motilidad empleando un procedimiento telemétrico. La información se totalizó de manera acumulativa a intervalos de 5 minutos y se analizó utilizando el algoritmo de Kalman. El método de estimación espectral empleado obedece a un sistema adaptativo basado en predicción lineal, dando lugar a un cálculo recursivo de los parámetros del filtro predictor. La optimización de este procedimiento se pone en evidencia al compararlo con el de Widrow, en el que la ganancia permanece en un valor previamente fijado (~ constante). Todos los tipos de comportamiento (excepto la alimentaciÓn) muestran picos destacados en la banda de frecuencia de 10-20 ciclos por día (período medio 96 minutos) habitual en muchos otros parámetros biológicos del hombre, asi aomo ritmicidades de periodos más cortos.Peer ReviewedPostprint (published version

Una experiencia malograda: la Sociedad de Socorros Mutuos del Clero (1847-1857)

Often, history contains bankrupt experiences, episodes that would remain forever unknown if the researcher´s work would not bring them to light. This is the case of the Society of Mutual Aids of the Clergy. Its creation responds to the initiative of a group of priests willing to find solutions to the difficult situation in which the clergy was, instead of complaining or missing past times, but also with the emulation desire, seen the good results, of the associations of workers that had begun to be constituted in Spain at those moments. However, Its short trajectory seems to have gone between economic difficulties and disagreements among its partners that finally will ruin the Society. In spite of this, many clergymen found in it an aid when more they needed it. Its final failure evidences, it is certain, the lack of solidarity and the lack of union of many of its members, but it does not hide those that responded positively and tried that the Society continued being a reality.A menudo, la historia encierra experiencias fallidas, episodios que de no ser por la labor del investigador, que las saca a la luz, permanecerían para siempre ignorados. Es el caso de la Sociedad de Socorros Mutuos del Clero. Su creación responde a la iniciativa de un grupo de sacerdotes dispuestos a encontrar soluciones a la difícil situación en que se hallaba sumido el clero, en lugar de lamentarse o añorar tiempos pasados, pero también al deseo de emulación, vistos los buenos resultados, de las asociaciones de trabajadores que en aquellos momentos habían empezado a constituirse en España. Sin embargo, su corta trayectoria parece hacer discurrido entre dificultades económicas y desacuerdos entre sus socios, que finalmente darán al traste con la Sociedad. Pese a esto, muchos clérigos hallaron en ella un socorro cuando más lo necesitaban. Su fracaso final evidencia, es cierto, la insolidaridad y la falta de unión de muchos de sus miembros, pero no oculta a los que respondieron positivamente y trataron de que la Sociedad continuase siendo una realidad

El clero liberal de la diócesis compostelana durante la primera mitad del siglo XIX: análisis e interpretación de un fenómeno peculiar

The traditional view of a Galician clergy who is massively committed to the absolutist cause should by no means hide the existence of a small, though active group, who apart from professing an open liberalism will play a major role in the dissemination of new approaches. Taking into account the diocesan clergy of Santiago, this fact, apart from telling us about a certain ideological diversification, becomes valuable evidence of the impact these new ideas will have on its members. Fear of reprisals may have prevented a bigger participation or a more intense activity on their side and the former might also account for the fact that it is in periods with a higher level of freedom, such as the years of the Courts of Cadiz or the Liberal Triennium, when their ideas normally come to light and become public.La clásica visión de un clero gallego comprometido masivamente con la causa absolutista no debe en modo alguno ocultar la existencia de un reducido, aunque activo grupo que además de profesar un liberalismo sin complejos, desempeñará un papel fundamental en la difusión de los nuevos planteamientos. Ateniéndonos al clero diocesano de Santiago, este hecho, aparte de informamos sobre una cierta diversificación ideológica, resulta un valioso testimonio para constatar el impacto de las nuevas ideas sobre sus miembros. Posiblemente el temor a las represalias haya impedido una participación más numerosa o una actividad más intensa por su parte, a la vez que explica que sea durante los períodos de mayor libertad, como los años de las Cortes de Cádiz o el Trienio, cuando aprovechen para salir a la luz y hacer públicas sus ideas