Physical and hydraulic properties of porous concrete

[Abstract:] The work presented includes a review of the state of art of porous concrete. Its purpose is to evaluate the potential use of porous concrete in constructions where the level of surface runoff justifies it. A review of the literature presented here has been necessary where parameters of special consideration have been defined in the dosage of permeable mixtures. The study includes the definition of porous concrete in terms of its main components: cement, coarse aggregate, water, additives, and sand, in little or no quantity, to cause the generation of an effective content of interconnected voids that allow rapid storm drainage. Given the reports of variables of high incidence in the mechanical behavior of porous concrete (resistance/permeability relationship), an investigation is warranted to synthesize the effects of the variables in the preparation of the mixture: water–cement ratio, granulometry, and morphology of the aggregates, compaction pressure, and curing techniques, among others. Likewise, the protocols for the characterization of porous concrete and additional aspects relevant to support the experimental phase are exposed, constituting a reference or anchor point for developing technologies associated with the manufacture of this material and the possibilities of its implementation in constructions

Accountability of the media as seen by Spanish citizens

This article analyses the opinions of citizens on the core values of the so-called Media accountability: truthfulness, independence, transparency, public participation and respect for peoples’ rights. It also analyses citizens’ perceptions of various deontological instruments to measure the effectiveness of compliance with these ethical values. The qualitative methodology used to carry out this analysis is part of the R+D+I research project “Accountability and Journalistic Cultures project in Spain. Impact and proposal of good practices in the Spanish media” (MediaACES), which has been achieved through six focus groups in different Spanish cities. The results of the analysis reflect the critical spirit of citizens towards the media due to the following factors: the absence of objectivity, the mixture of economic interests with their editorial line and an ambiguous participation of the public, which requires a better definition of their role within the information process. The conclusions derived from this analysis allow us to reflect on several aspects: among others, the competition in a deregulated market leads to infotainment and affects the quality of information, as well as the rights of people affected by the news. At the same time, the excess of information channels leads to greater disinformation, under the appearance of a spontaneous pluralism that is superfluous. Ethics, therefore, seems to be a necessary requirement to differentiate professional journalism from other inappropriate information channels and to guarantee the right to information of citizens.El presente artículo analiza las opiniones de los ciudadanos sobre los valores centrales de la denominada Media Accountability: veracidad, independencia, transparencia, participación del público y respeto a los derechos de las personas. Asimismo, se estudia la percepción de la ciudadanía hacia diversos instrumentos deontológicos para medir la eficacia del cumplimiento de dichos valores éticos. La metodología cualitativa empleada para realizar este análisis, enmarcado en el proyecto I+D+i “Accountability y Culturas Periodísticas en España. Impacto y propuesta de buenas prácticas en los medios de comunicación españoles” (MediaACES), se ha concretado mediante la realización de seis grupos de discusión (focus groups) en diversas ciudades del territorio español. Los resultados reflejan el espíritu crítico de la ciudadanía hacia los medios de comunicación por los siguientes factores: la ausencia de objetividad, la mezcla de intereses económicos con su línea editorial y una ambigua participación del público, que exige definir mejor su rol dentro del proceso informativo. Las conclusiones permiten reflexionar sobre diversos aspectos, entre otros, que la competencia en un mercado desregularizado conduce al infoespectáculo y afecta a la calidad informativa y los derechos de las personas afectadas por las noticias. Asimismo, el exceso de canales de información conduce a una mayor desinformación, bajo la apariencia de un pluralismo espontáneo que resulta superfluo. La ética, por tanto, se antoja como una exigencia necesaria para distinguir el periodismo profesional de otras opciones informativas impropias y garantizar el derecho a la información de los ciudadanos

Response for light scattered in the ocular fundus from double-pass and Hartmann–Shack estimations

Double-pass (DP) and Hartmann--Shack (HS) are complementary techniques based on reflections of light in the ocular fundus that may be used to estimate the optical properties of the human eye. Under conventional data processing, both of these assessment modes provide information on aberrations. In addition, DP data contain the effects of scattering. In the ocular fundus, this phenomenon may arise from the interaction of light with not only the retina, but also deeper layers up to which certain wavelengths may penetrate. In this work, we estimate the response of the ocular fundus to incident light by fitting the deviations between DP and HS estimations using an exponential model. In measurements with negligible intraocular scattering, such differences may be related to the lateral spreading of light that occurs in the ocular fundus due to the diffusive properties of the media at the working wavelength. The proposed model was applied in young healthy eyes to evaluate the performance of scattering in such a population. Besides giving a parameter with information on the ocular fundus, the model contributes to the understanding of the differences between DP and HS estimations.Postprint (author's final draft

Diseño del encofrado para muros usando encofrados modulares

Concrete is one of the most versatile materials used in construction. At present, it is extensively employed in the industry as it can be molded in almost any shape through rigid molds called formwork. The arrangement of the different elements that compose the formwork and its associated restrictions pose interesting computational challenges that directly impact the construction industry. In this article, we propose the implementation of a model with constraints that generates a formwork layout for rectilinear walls using modular forms. This approach is based on the decomposition of walls and their representation as instances of the change-making problem. For that purpose, we used the concept of oriented rectangular decomposition to simplify the problem input and address the solution as a Constraint Optimization Problem (COP). The experiments with test inputs provided solutions in less than 200 seconds, thus offering a practical and efficient approach to the complex task of formwork design.  El concreto u hormigón es uno de los materiales más versátiles usados en la construcción.  En la actualidad, se usa extensivamente en la industria, ya que puede ser moldeado de formas casi arbitrarias a través de moldes rígidos denominados encofrados. La manera en que se disponen los distintos elementos para formar el encofrado y las restricciones asociadas, genera retos computacionales interesantes que impactan directamente la industria de la construcción. En este artículo se propone la implementación de un modelo de restricciones que genera encofrados para muros rectilíneos usando formaletas modulares. Este enfoque se basa en la descomposición de muros y su representación en instancias del problema de cambio de monedas. Para este propósito, se utiliza el concepto de descomposición rectangular orientada para simplificar la entrada del problema y abordar la solución como un problema de optimización por restricciones (COP). Los experimentos con entradas de prueba ofrecen soluciones en tiempos inferiores a 200 segundos, cuyo resultado es un enfoque práctico y eficiente para la compleja tarea del diseño de encofrados

Democracia electoral en Colombia desde una visión de competencia

El presente artículo pretende exponer el funcionamiento de la democracia electoral en Colombia, desde la teoría competitiva de John Schumpeter. A partir del acontecer histórico nacional se pretende comprender cuál es el impacto y qué significa el proceso de elecciones en esta sociedad. Como la intención es comprender cómo se ha desarrollado la democracia en Colombia, es necesario definir en un primer momento los conceptos claves para entender qué es democracia, específicamente la electoral y competitiva. A continuación, analizar el comportamiento electoral en Colombia, a través de datos cuantitativos y cualitativos sobre las últimas elecciones, respecto a temas como legitimidad, valor y abstencionismo; variables que permitirán identificar cuáles son las principales debilidades para la democracia en el país. Con la intención de aplicar el alcance teórico, se hará un breve análisis acerca del comportamiento político en Bogotá, como capital del país y como centro del movimiento político nacional, esto permitirá alcanzar una comprensión valiosa sobre la democracia en Colombia

Prototipo de un sistema de generación de energía eléctrica basado en energía solar, para la iluminación y funcionamiento de dispositivos de hasta 200 watts : caso de estudio: sector los Laureles municipio Turbaco - Bolívar

Las Zonas No Interconectadas (ZNI), son a aquellas áreas del país que no cuentan con el suministro de energía eléctrica a través del sistema de interconexión nacional. La necesidad de energía eléctrica en estos territorios, ha llevado a buscar formas de generación de bajo impacto ambiental que además permitan el desarrollo sostenible de la zona. El distanciamiento de las veredas, corregimientos y caseríos, a los centros urbanos, ha limitado la construcción de infraestructura para llevar el servicio de fluido eléctrico a estos lugares Colombia es un país que se caracteriza por su riqueza natural y diversidad en las condiciones climáticas de sus regiones, es privilegiada también con gran radiación solar durante la mayor parte del año principalmente en la región Caribe, que en promedio recibe 5.5 KWh/m2 durante 5 horas diarias1 , esta ventaja natural sobre otros países permite la generación de energías limpias por medio de métodos de recolección solar (Paneles Solares Fotovoltaicos). En la elaboración de este trabajo se plantea el uso de la energía solar fotovoltaica como fuente de alimentación para suplir a una carga de hasta 200 W, distribuida en iluminación y un dispositivo de baja potencia para el sector los Laureles en el municipio de Turbaco del departamento de Bolívar.Incluye bibliografía, anexo

Robot-aided tunnel inspection and maintenance system by vision and proximity sensor integration

This article describes an unprecedented alternative to manual procedures for the application of advanced composite materials, such as Fiber Reinforced Polymer (FRP) and epoxy resins. A complete mobile integrated system is presented for the inspection and maintenance of concrete surfaces in tunnels. It allows performance of operations with minimum interference on passing traffic. The core of this system resides in a specially designed light-weight robotic tool, which is sensed and automated for processes. Sensing includes vision and a laser telemeter to assure precise inspection, superficial preparation, and composite application. The designed interconnection flange allows simple and robust attachment of the tool to a robotic arm's tip. The robot&-tool set is to be mounted on a standard articulated lift platform. Therefore, an operator can direct the platform and the robot&-tool set's operations from a control station placed at ground-level, in a wheeled vehicle on which the articulated lift platform is mounted. A graphical Human&-Machine Interface (HMI) has been developed for the system. It allows the operator to identify fissures for the injection of epoxy resin, and weakened surfaces for FRP adhesion. Actual procedures are planned and performed by the system's automatic components.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

Experience acquisition simulator for operating microtuneling boring machines

This paper describes an innovative modeling, interfacing and training framework and application for microtunneling machines under heterogeneous gravel and sand soils, based on a machine simulator. It is initialized using a selective collection of skilled pilots' know-how during the performance of a pipe jacking microtunneling machine operation, generating a rule-based system based on grouped rules and states that replicate the machine's performance. The adjustment of these states and associated rules allows the creation, setup and analysis of a realistic functional model for tunneling machines. The developed system integrates a friendly Human-Machine Interface (HMI) that closely resembles real machines' pilot cabinets and allows natural interaction with the implemented inference engine through the simulated control panel. Additionally, the framework allows the training of tunneling machine operators by simulation and subsequent gathered data analysis, obviating or reducing mechanical movement times if desired. The virtual pilot's desk allows global training time and cost reductions, and increases safety for future operatorsand machinery. The HMI is divided into two screens, which replicate the data and the command panels of a real machine's control desk. The presented framework has allowed the first implementation of a jack piping microtunneling machine simulator by means of the developed pilots' steering know-how capture methodology.This work has been funded by the Spanish government under the framework of the Multidimensional City project PSE-380000-2008-5 http://www.laciudadmultidimensional.es, and has received funding from the RoboCity2030-II-CM project (S2009/DPI-1559), funded by Programas de Actividades I+D en la Comunidad de Madrid and cofunded by Structural Funds of the EU

Flexible field factory for construction industry

Purpose - The paper aims to present the concept, the layout design and the evaluation performed of a flexible field factory for construction industry. Both the concept and layout are focused on flexibility and mobility factors, providing a versatile system for manufacturing and assembly that can be transported to construction sites without need of special permissions. Design/methodology/approach - The design is based on the design for manufacture and assembly (DFMA) principles, lean manufacturing, and construction industry experts' knowledge. Findings - The developed factory layout is dimensioned to fit in a standard 20-feet-long container. Simulation processes have been run to verify the viability of the system. The time estimates calculated in the simulations are compared with traditional in and off-site construction method estimates, providing quantified cost and time benefits. Originality/value - This paper presents the concept of the robotized field factory designed for on-site prefabrication, the design of which began during the EU 6FP ManuBuild Project. This reconfigurable and flexible system is oriented to the production of small and medium size modular systems. The viability of the field factory has been evaluated thanks to the application of a modular system for building installations called Service Core. Its design has been based on DFMA and lean principles as well as the expertise from construction partners from the ManuBuild Project.This work has been funded by the E.U. community under FP6 Project ManuBuild and also supported by CAM project S2009/DPI-1559/ROBOCITY2030 II. The authors would also like to acknowledge the work of the other partners involved in the project: DRAGADOS, and Fraunhofer IAO