Directional impulse response of a large cavity inside a sonic crystal

Both temporal and directional responses of a cavity inside a two-dimensional sonic crystal are investigated. The size of the cavity is large compared to the lattice parameter and the wavelength for the frequency range of interest. Hence, a hybrid method to compute the response is proposed, combining multiscattering theory for the calculation of the reflective properties of the sonic crystal with a modified ray-tracing algorithm for the sound propagation within the cavity. The response of this enclosure displays resonances for certain frequency bands that depend on the geometry of the lattice and the cavity. When a full band gap exists in the sonic crystal, rays cannot propagate through the medium and total reflection occurs for all incidence angles, leading to strong resonances with an isotropic intensity field inside the cavity. When only some propagation directions are forbidden, total reflection occurs for certain ranges of incidence angles, and resonances can also be elicited but with a highly anisotropic intensity field. The spectrum of resonances of the cavity is strongly affected by changes in the lattice geometry, suggesting that they can be tailored to some extent, a feature that can lead to potential applications in architectural acoustics.Fil: Spiousas, Ignacio. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Eguia, Manuel Camilo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A methodological approach for designing and sequencing product families in Reconfigurable Disassembly Systems

Purpose: A Reconfigurable Disassembly System (RDS) represents a new paradigm of automated disassembly system that uses reconfigurable manufacturing technology for fast adaptation to changes in the quantity and mix of products to disassemble. This paper deals with a methodology for designing and sequencing product families in RDS. Design/methodology/approach: The methodology is developed in a two-phase approach, where products are first grouped into families and then families are sequenced through the RDS, computing the required machines and modules configuration for each family. Products are grouped into families based on their common features using a Hierarchical Clustering Algorithm. The optimal sequence of the product families is calculated using a Mixed-Integer Linear Programming model minimizing reconfigurability and operational costs. Findings: This paper is focused to enable reconfigurable manufacturing technologies to attain some degree of adaptability during disassembly automation design using modular machine tools. Research limitations/implications: The MILP model proposed for the second phase is similar to the well-known Travelling Salesman Problem (TSP) and therefore its complexity grows exponentially with the number of products to disassemble. In real-world problems, which a higher number of products, it may be advisable to solve the model approximately with heuristics. Practical implications: The importance of industrial recycling and remanufacturing is growing due to increasing environmental and economic pressures. Disassembly is an important part of remanufacturing systems for reuse and recycling purposes. Automatic disassembly techniques have a growing number of applications in the area of electronics, aerospace, construction and industrial equipment. In this paper, a design and scheduling approach is proposed to apply in this area. Originality/value: This paper presents a new concept called Reconfigurable Disassembly System, which represents disassembly systems with reusability, scalability, agility and reconfigurability features. These features and some specific costs are considered as part of the proposed methodology.Peer Reviewe

Multi-objective Vehicle Routing Problem with Cost and Emission Functions

AbstractAmong the logistics activities, transportation, is presented as a major source of air pollution in Europe, generating harmful levels of air pollutants and is responsible for up to 24% of greenhouse gases (GHGs) emissions in the European Union. The growing environmental concern related to the economic activity has been transferred to the field of transport and logistics in recent decades. Therefore, environmental targets are to be added to economic targets in the decision-making, to find the right balance between these two dimensions. In real life, there are many situations and problems that are recognized as multi-objective problems. This type of problems containing multiple criteria to be met or must be taken into account. Often these criteria are in conflict with each other and there is no single solution that simultaneously satisfies everyone. Vehicle routing problems (VRP) are frequently used to model real cases, which are often established with the sole objective of minimizing the internal costs. However, in real life other factors could be taken into account, such as environmental issues. Moreover, in industry, a fleet of vehicles is rarely homogeneous. The need to be present in different segments of the market, forcing many companies to have vehicles that suit the type of goods transported. Similarly, to have vehicles of different load capacities enables a better adaptation to the customer demand. This paper proposes a multi-objective model based on Tchebycheff methods for VRP with a heterogeneous fleet, in which vehicles are characterized by different capacities, costs and emissions factors. Three objective functions are used to minimize the total internal costs, while minimizing the CO2 emissions and the emission of air pollutants such as NOx. Moreover, this study develops an algorithm based on C&W savings heuristic to solve the model when time windows are not considered. Finally, a real case application is analyzed to confirm the practicality of the model and the algorithm

Experiencias de gamificación en aulas

Experiencias de gamificación en aulas / Contreras Espinosa, Ruth S.; Eguia, José Luis -- Gamificación en escenarios educativos. Revisando literatura para aclarar conceptos / Contreras Espinosa, Ruth S. -- Gamificación con PBL para una signatura del grado de Maestro de Educación Infantil / Revuelta Domínguez, Francisco Ignacio; Guerra Antequera, Jorge; Pedrera Rodríguez, Inmaculada -- Del Storytelling al Storylearning. Como motivar a los alumnos de guión y diseño multimedia / Legerén Lago, Beatriz -- Aprendizaje y motivación de la semiótica aplicada. Gamificación con base en la prueba piloto de la plataforma "Aprendiz" / Lugo, Nohemí; Alcántara, Alejandro -- Ethos files : un juego de rol para el área de "valores éticos" / Rubio Méndez, María -- Reader Wars : motivar a los alumnos por la lectura / Paula, Oscar de -- Evaluación y rediseño de una experiencia de gamificación en el aula basada en estilos de aprendizaje y tipos de jugador / Baldeón, Johan; Rodríguez, Inmaculada; Puig, Anna; Lopez-Sanchez, Maite -- Aprender a diseñar diseñando y jugando Serious Games en las aulas / Morales Moras, JoanEste libro pretende reunir experiencias e ideas de un grupo de profesores y expertos en distintos espacios educativos. Además, tiene como intento, anclar el concepto “gamificación” en el creciente cuerpo de literatura sobre esta área y demostrar ejemplos prácticos en asignaturas reales. La gamificación se refiere a un proceso de mejora, con posibilidades para proporcionar experiencias de juego y con el fin de apoyar a las actividades que desarrollan los usuarios. Las definiciones que se han descrito al inicio de la presentación, se han basado en la noción de que la gamificación procede del uso de elementos de diseño de juegos. Sin embargo, no parece haber un conjunto de elementos de juego claramente definidos, es decir, elementos que son estrictamente exclusivos de los juegos pero que no dan lugar automáticamente a experiencias de juego. La gamificación no siempre se lleva a cabo solo a través de elementos concretos. Por lo tanto, se cree que basar estas definiciones en un conjunto de mecanismos es un tema que puede causar confusión. En su lugar, propone que la gamificación podría entenderse de una forma mucho más amplia, y como un proceso en el que el “gamificador” intenta aumentar las probabilidades de la aparición de diferentes experiencias de juego al contagiar posibilidades para ese fin (ya sea mediante distintivos, puntos, etc.)

Experiencias de gamificación en aulas

Experiencias de gamificación en aulas / Contreras Espinosa, Ruth S.; Eguia, José Luis -- Gamificación en escenarios educativos. Revisando literatura para aclarar conceptos / Contreras Espinosa, Ruth S. -- Gamificación con PBL para una signatura del grado de Maestro de Educación Infantil / Revuelta Domínguez, Francisco Ignacio; Guerra Antequera, Jorge; Pedrera Rodríguez, Inmaculada -- Del Storytelling al Storylearning. Como motivar a los alumnos de guión y diseño multimedia / Legerén Lago, Beatriz -- Aprendizaje y motivación de la semiótica aplicada. Gamificación con base en la prueba piloto de la plataforma "Aprendiz" / Lugo, Nohemí; Alcántara, Alejandro -- Ethos files : un juego de rol para el área de "valores éticos" / Rubio Méndez, María -- Reader Wars : motivar a los alumnos por la lectura / Paula, Oscar de -- Evaluación y rediseño de una experiencia de gamificación en el aula basada en estilos de aprendizaje y tipos de jugador / Baldeón, Johan; Rodríguez, Inmaculada; Puig, Anna; Lopez-Sanchez, Maite -- Aprender a diseñar diseñando y jugando Serious Games en las aulas / Morales Moras, JoanEste libro pretende reunir experiencias e ideas de un grupo de profesores y expertos en distintos espacios educativos. Además, tiene como intento, anclar el concepto “gamificación” en el creciente cuerpo de literatura sobre esta área y demostrar ejemplos prácticos en asignaturas reales. La gamificación se refiere a un proceso de mejora, con posibilidades para proporcionar experiencias de juego y con el fin de apoyar a las actividades que desarrollan los usuarios. Las definiciones que se han descrito al inicio de la presentación, se han basado en la noción de que la gamificación procede del uso de elementos de diseño de juegos. Sin embargo, no parece haber un conjunto de elementos de juego claramente definidos, es decir, elementos que son estrictamente exclusivos de los juegos pero que no dan lugar automáticamente a experiencias de juego. La gamificación no siempre se lleva a cabo solo a través de elementos concretos. Por lo tanto, se cree que basar estas definiciones en un conjunto de mecanismos es un tema que puede causar confusión. En su lugar, propone que la gamificación podría entenderse de una forma mucho más amplia, y como un proceso en el que el “gamificador” intenta aumentar las probabilidades de la aparición de diferentes experiencias de juego al contagiar posibilidades para ese fin (ya sea mediante distintivos, puntos, etc.)

Guayamba 2: Addressing the domestic space in the eastern forests of Catamarca

El siguiente trabajo tiene como objetivo presentar los primeros resultados obtenidos de las investigaciones realizadas en el sitio Guayamba 2, ubicado en la localidad homónima, en el departamento de El Alto, provincia de Catamarca. El asentamiento se compone de cuatro estructuras y se encuentra en el área de Bosque Serrano. Se relaciona con Casa Pintada, un alero con representaciones rupestres, localizado a unos 190 m en línea recta hacia el sur. Hasta el momento hemos realizado dos sondeos en dos estructuras y comenzado la excavación de una tercera. A partir de estos trabajos hemos recuperado: fragmentos cerámicos, restos líticos y algunos restos óseos faunísticos. El análisis del material recuperado indicaría que en el sitio se realizaron diversas prácticas domésticas (preparación y consumo de alimentos, elaboración de artefactos líticos, entre otras) consistentes con un sitio de habitación permanente.The following work aims to present the preliminary results of the investigations carried out at the Guayamba 2 site, which is located in the homonymous locality, in the department of El Alto, Catamarca province. The settlement consists of four structures and is located in the humid forest zone of Sierra de El Alto Ancasti region. It is related to Casa Pintada, a cave with rock art representations, located about 190 m in a straight line to the south. So far, our team has done two surveys in two structures and we have begun the excavation of the third. From these studies we have recover: ware shreds and lithic remains, and some fauna. The results of the analysis of the recovered material would indicate that in the site a variety of domestic practices were performed (preparation and consumption of food, elaboration of lithic artefacts, among others) consistent with a site of permanent occupation.Fil: Eguia, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Arqueología; ArgentinaFil: Prieto, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Arqueología; ArgentinaFil: Gerola, Ignacio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Arqueología; Argentin

A methodological approach for designing and sequencing product families in Reconfigurable Disassembly Systems

Purpose: A Reconfigurable Disassembly System (RDS) represents a new paradigm of automated disassembly system that uses reconfigurable manufacturing technology for fast adaptation to changes in the quantity and mix of products to disassemble. This paper deals with a methodology for designing and sequencing product families in RDS. Design/methodology/approach: The methodology is developed in a two-phase approach, where products are first grouped into families and then families are sequenced through the RDS, computing the required machines and modules configuration for each family. Products are grouped into families based on their common features using a Hierarchical Clustering Algorithm. The optimal sequence of the product families is calculated using a Mixed-Integer Linear Programming model minimizing reconfigurability and operational costs. Findings: This paper is focused to enable reconfigurable manufacturing technologies to attain some degree of adaptability during disassembly automation design using modular machine tools. Research limitations/implications: The MILP model proposed for the second phase is similar to the well-known Travelling Salesman Problem (TSP) and therefore its complexity grows exponentially with the number of products to disassemble. In real-world problems, which a higher number of products, it may be advisable to solve the model approximately with heuristics. Practical implications: The importance of industrial recycling and remanufacturing is growing due to increasing environmental and economic pressures. Disassembly is an important part of remanufacturing systems for reuse and recycling purposes. Automatic disassembly techniques have a growing number of applications in the area of electronics, aerospace, construction and industrial equipment. In this paper, a design and scheduling approach is proposed to apply in this area. Originality/value: This paper presents a new concept called Reconfigurable Disassembly System, which represents disassembly systems with reusability, scalability, agility and reconfigurability features. These features and some specific costs are considered as part of the proposed methodology.Peer Reviewe

Time reversal focusing in the audible range using a tunable sonic crystal

Time reversal (TR) focusing of acoustical waves is a widely studied phenomenon that usually requires a chaotic cavity or disordered scattering medium to achieve spatial and frequency decorrelation of the acoustic field when using a single channel. On the other hand, sonic crystals were disregarded as scattering media for the TR process because of their periodic structure and previous results showing poor spatial focusing when compared to a disordered medium. In this paper, an experimental realization of a tunable sonic crystal, which can achieve single-channel TR focusing amplitudes in the audible range comparable to those obtained in a disordered scattering medium, is presented. Furthermore, the tunable nature of the system allows it to switch the time-reversed pulse on and off by changing its geometrical configuration. A robustness analysis with respect to the perturbations in the sonic crystal configurations is also presented, showing that the time-reversed pulses with high temporal and spatial contrasts are preserved only for configurations that are close to the original one.Fil: Gomez, Valeria Sol. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Spiousas, Ignacio. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Eguia, Manuel Camilo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A methodological approach for designing and sequencing product families in Reconfigurable Disassembly Systems

Purpose: A Reconfigurable Disassembly System (RDS) represents a new paradigm of automated disassembly system that uses reconfigurable manufacturing technology for fast adaptation to changes in the quantity and mix of products to disassemble. This paper deals with a methodology for designing and sequencing product families in RDS. Design/methodology/approach: The methodology is developed in a two-phase approach, where products are first grouped into families and then families are sequenced through the RDS, computing the required machines and modules configuration for each family. Products are grouped into families based on their common features using a Hierarchical Clustering Algorithm. The optimal sequence of the product families is calculated using a Mixed-Integer Linear Programming model minimizing reconfigurability and operational costs. Findings: This paper is focused to enable reconfigurable manufacturing technologies to attain some degree of adaptability during disassembly automation design using modular machine tools. Research limitations/implications: The MILP model proposed for the second phase is similar to the well-known Travelling Salesman Problem (TSP) and therefore its complexity grows exponentially with the number of products to disassemble. In real-world problems, which a higher number of products, it may be advisable to solve the model approximately with heuristics. Practical implications: The importance of industrial recycling and remanufacturing is growing due to increasing environmental and economic pressures. Disassembly is an important part of remanufacturing systems for reuse and recycling purposes. Automatic disassembly techniques have a growing number of applications in the area of electronics, aerospace, construction and industrial equipment. In this paper, a design and scheduling approach is proposed to apply in this area. Originality/value: This paper presents a new concept called Reconfigurable Disassembly System, which represents disassembly systems with reusability, scalability, agility and reconfigurability features. These features and some specific costs are considered as part of the proposed methodology

Time reversal focusing in the audible range using a tunable sonic crystal

Time reversal (TR) focusing of acoustical waves is a widely studied phenomenon that usually requires a chaotic cavity or disordered scattering medium to achieve spatial and frequency decorrelation of the acoustic field when using a single channel. On the other hand, sonic crystals were disregarded as scattering media for the TR process because of their periodic structure and previous results showing poor spatial focusing when compared to a disordered medium. In this paper, an experimental realization of a tunable sonic crystal, which can achieve single-channel TR focusing amplitudes in the audible range comparable to those obtained in a disordered scattering medium, is presented. Furthermore, the tunable nature of the system allows it to switch the time-reversed pulse on and off by changing its geometrical configuration. A robustness analysis with respect to the perturbations in the sonic crystal configurations is also presented, showing that the time-reversed pulses with high temporal and spatial contrasts are preserved only for configurations that are close to the original one.Fil: Gomez, Valeria Sol. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Spiousas, Ignacio. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Eguia, Manuel Camilo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Acústica y Percepción Sonora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin