1,220 research outputs found

    A Kinetic Model for Grain Growth

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    We provide a well-posedness analysis of a kinetic model for grain growth introduced by Fradkov which is based on the von Neumann-Mullins law. The model consists of an infinite number of transport equations with a tri-diagonal coupling modelling topological changes in the grain configuration. Self-consistency of this kinetic model is achieved by introducing a coupling weight which leads to a nonlinear and nonlocal system of equations. We prove existence of solutions by approximation with finite dimensional systems. Key ingredients in passing to the limit are suitable super-solutions, a bound from below on the total mass, and a tightness estimate which ensures that no mass is transported to infinity in finite time.Comment: 24 page

    Implementación de sistema domótico con servidor Raspberry

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    Este proyecto consiste en el diseño e implementación un sistema domótico que puede ser instalado en una vivienda para controlar distintas variables ambientales y conseguir así la máxima comodidad de los habitantes de manera automática o manual según los gustos y necesidades de los usuarios. La característica principal de este sistema, es que cuenta con un funcionamiento distribuido donde entran en juego un servidor, encargado de tomar las decisiones generales para el comportamiento de la casa, y una serie de controladores esclavo cuya función es mantener constantes las variables ambientales con los valores fijados por el servidor. Así se consigue mantener la vivienda en una situación de bienestar constante para cualquier persona que se encuentre dentro. El sistema ha sido pensado de manera que se intenta reducir al máximo el cableado para facilitar su instalación por lo que la comunicación entre los distintos dispositivos se hace de manera inalámbrica por medio de un protocolo descrito en la norma IEEE 802.15.4 llamado ZigBee. Para ello se ha utilizado un módulo de comunicación wireless llamado Xbee, el cual permite la comunicación entre dos dispositivos. Para el control de dicho sistema distribuido se cuenta con una aplicación web, que mediante una interfaz gráfica permite al usuario controlar los distintos dispositivos dentro de la vivienda consiguiendo así controlar las variables ambientales a gusto del usuario. Dicha interfaz gráfica no depende de un software específico, sino que sólo es necesario un cliente http como podría ser Internet Explorer, Mozilla Firefox, Google Chrome, etc. Para integrar dicho sistema se ha usado un mini ordenador de bajo coste llamado RaspBerryPi, en el que se encuentra alojado un servidor Apache con el fin de gestionar y automatizar las variables ambientales. El control de los dipositivos encargados de modificar y estabilizar las variables ambientales se realiza mediante unos controladores genéricos implementados mediante mcontroladores 80C51F410, pertenecientes a la familia 80C51, y una serie de componentes y circuitería que permiten el correcto funcionamiento de éstos. Existen dos tipos de controladores distintos, los cuales son: Controlador Sensor: Encargados de las tomas de valores ambientales como puede ser la luz y la temperatura. Controladores Actuadores: Encargados de actuar sobre los dispositivos que modifican y estabilizan las variables ambientales como pueden ser la calefacción, tiras de leds de iluminación, persianas, alarmas, etc. El conjunto de la RaspBerryPi y los diferentes controladores forman el prototipo diseñado para este proyecto fin de carrera, el cual puede ser ampliado sencillamente para abarcar una amplia gama de posibilidades y funcionalidades dentro de la comodidad de una vivienda. ABSTRACT. The project described in this report consisted designing and implementing a home automation system that could be installed in a house in order to control environmental variables and thus get the maximum comfort of the inhabitant automatically or manually according to their tastes and needs. The main feature of this system consists in a distributed system, formed by a server which is responsible for making the main decisions of the actions performed inside the house. In addition, there are a series of slave controlers whose function consists in keeping the environmental variables within the values established by the server. Thus gets to keep the home in a situation of constant wellbeing to anyone who is inside. The system has been designed in order to reduce the amount of wire needed for the inter-connection of the devices, by means of wireless communication. The devices chosen for the solution are Xbee modules, which use the Zigbee protocol in order to comunicate one between each other. The Zigbee protocol is fully described in the IEEE 802.15.4 standard. A web application has been used to control the distributed system. This application allows users to control various devices inside the house and subsequently the different environmental variables. This implementation allows obtaining the maximum comfort by means of a very simple graphical interface. In addition, the Graphical User Interface (GUI) does not depend on any specific software. This means that it would only be necessary a http client (such as Internet Explorer, Mozilla Firefox, Google Chrome, etc.) for handling the application. The system has been integrated using a low-cost mini computer called RaspBerryPi.This computer has an Apache server allocated which allows to manage and to automatize the different environmental variables. Furthermore, for changing and stabilizing those variables, some generic controllers have been developed, based on mcontrollers 80C51F410. There have been developed mainly two different types of controllers: Sensor Controllers, responsible for measuring the different environmental values, such as light and temperature; and Actuator Controllers, which purpose is to modify and stabilize those environmental variables by actuating on the heating, the led lamps, the blinders, the alarm, etc. The combination of the RaspBerryPi and the different controllers conform the prototype designed during this project. Additionally, this solution could be easily expanded in order to intake further functionalities adapted to new needs that could arise in the future

    Scalar QED as a toy model for higher-order effects in classical gravitational scattering

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    Quantum Electrodynamics (QED) serves as a useful toy model for classical observables in gravitational two-body systems with reduced complexity due to the linearity of QED. We investigate scattering observables in scalar QED at the sixth order in the charges (two-loop order) in a classical regime analogous to the post-Minkowskian expansion in General Relativity. We employ modern scattering amplitude tools and extract classical observables by both eikonal methods and the formalism of Kosower, Maybee, and O'Connell (KMOC). In addition, we provide a simplified approach to extracting the radial action beyond the conservative sector.Comment: 44pages; Results included as an ancillary fil

    Life cycle assessment of a disposable and a reusable surgery instrument set for spinal fusion surgeries

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    Producción CientíficaThe worldwide increasing wealth and increased life expectancy of humans has led to an increase in the number of medical procedures and surgeries. Surgeries are complex medical procedures which contribute to a significant share of the total environmental impact of the healthcare system. Among other important sources of environmental impacts from surgeries, material consumption due to required instrumentation accounts for up to 65 % of greenhouse gas emissions from surgeries. This study investigates how a disposable and a reusable surgery instrument sets for lumbar fusion surgeries contribute to the environmental impact and which system is more advantageous for the environment. For lumbar fusion surgeries, reusable and disposable instrumentation and implant sets are commercially available. Both sets are capable to support a one level lumbar fusion surgery. The reusable set is comprehensive and fully opened before the surgery, while the disposable system comes in a modular box system, and the boxes are opened on demand during the surgery. To compare the environmental impact of these different configurations, a comparative Life Cycle Assessment (LCA) was performed to assess the overall environmental impacts of both alternatives. One of the key findings is that the selected cleaning and sterilization process for reusable instruments is responsible for up to 90 % of the greenhouse gas emissions and decides which system is advantageous from an environmental perspective. Reducing the number of instruments to be cleaned and sterilized for a surgery should be the focus for future surgery instruments development from an environmental perspective

    The capability of square-meshes and fixed-shape meshes to control codend size selection

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    Trawl codends are commonly made of diamond-mesh netting. However, diamond-mesh codends vary in mesh geometry along its length and during fishing due to catch build up. This introduces variability in the size selection process. This phenomenon compromises the rationality of regulating exploitation patterns in trawl fisheries through adjustments in codend mesh size. One technical solution often applied to achieve more welldefined size selection is turning the codend netting 45 degrees (square-mesh). However, there is a lack of evidence that square-mesh codends result in more constant size selectivity. Therefore, we aimed at quantifying the variability in size selection in square-mesh codends. We tested the size selectivity of three codends; a standard square-mesh codend, and two rigid codends where mesh geometries were fixed in diamond shape with an opening angle of 60◦ and square shape, respectively. The two rigid codends were used to establish baselines with limited variability in size selection. The size selectivity of these codends was compared to results - previously obtained for a standard diamond-mesh codend. Using Atlantic cod (Gadus morhua) as a case study, we demonstrated that the standard square-mesh codend had significantly larger variability in size selection compared to the fixed diamond-mesh codend. Moreover, we found no evidence that the standard square-mesh codend had lower variability in size selection than a standard diamond-mesh codend with same mesh size. These results demonstrate that the use of standard square-mesh codends is not sufficient to reduce variability in codend size selection. Additionally, we demonstrate that the sizes of fish retained is strongly dependent on mesh shape and openness. We conclude that a profound re-thinking over codend designs is required in order to achieve better control of size selection in trawl fisheries

    Culture and group-functional punishment behaviour

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    Funding. Financial support from the Spanish Ministry of Science and Innovation (PGC2018-093506-B-I00, ECO2013-44879-R) and theRegionalGovernment ofAndalusia (PY18-FR-0007, P11-SEJ-8286 and P12-SEJ-1436) is gratefully acknowledged.Antonio Espín acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 754446 and UGR Research and Knowledge Transfer Fund – Athenea3i. Funding for open access charge: Universidad de Granada.Data availability statement. The dataset and code (STATA) are available at: http://hdl.handle.net/10481/76057Supplementary material. To view supplementary material for this article, please visit https://doi.org/10.1017/ehs.2022.32Humans often ‘altruistically’ punish non-cooperators in one-shot interactions among genetically unrelated individuals. This poses an evolutionary puzzle because altruistic punishment enforces cooperation norms that benefit the whole group but is costly for the punisher. One key explanation is that punishment follows a social-benefits logic: it is eminently normative and group-functional (drawing on cultural group selection theories). In contrast, mismatch-based deterrence theory argues that punishment serves the individual- level function of deterring mistreatment of oneself and one’s allies, hinging upon the evolved human coalitional psychology. We conducted multilateral-cooperation experiments with a sample of Spanish Romani people (Gitanos or Calé) and the non-Gitano majority. The Gitanos represent a unique case study because they rely heavily on close kin-based networks and display a strong ethnic identity. We find that Gitano non-cooperators were not punished by co-ethnics in only-Gitano (ethnically) homogeneous groups but were harshly punished by other Gitanos and by non-Gitanos in ethnically mixed groups. Our findings suggest the existence of culture-specific motives for punishment: Gitanos, especially males, appear to use punishment to protect their ethnic identity, whereas non-Gitanos use punishment to protect a norm of universal cooperation. Only theories that consider normative, group-functional forces underlying punishment behaviour can explain our data.Spanish Ministry of Science and Innovation (PGC2018-093506-B-I00, ECO2013-44879-R)Regional Government ofAndalusia (PY18-FR-0007, P11-SEJ-8286 and P12-SEJ-1436)European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 754446UGR Research and Knowledge Transfer Fund – Athenea3iFunding for open access charge: Universidad de Granad

    First measurements of a scintillator based fast-ion loss detector near the ASDEX Upgrade divertor

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    A new reciprocating scintillator based fast-ion loss detector has been installed a few centimeters above the outer divertor of the ASDEX Upgrade tokamak and between two of its lower Edge Localized Modes (ELM) mitigation coils. The detector head containing the scintillator screen, Faraday cup, calibration lamp, and collimator systems are installed on a motorized reciprocating system that can adjust its position via remote control in between plasma discharges. Orbit simulations are used to optimize the detector geometry and velocity-space coverage. The scintillator image is transferred to the light acquisition systems outside of the vacuum via a lens relay (embedded in a 3D-printed titanium holder) and an in-vacuum image guide. A charge coupled device camera, for high velocity-space resolution, and an 8 × 8 channel avalanche photo diode camera, for high temporal resolution (up to 2 MHz), are used as light acquisition systems. Initial results showing velocity-space of neutral beam injection prompt losses and fast-ion losses induced by a (2, 1) neoclassical tearing mode are presented.EURATOM 63305
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