Comparative analysis between Italian and Spanish ceramic tile

Treball final de Grau en Administració d’Empreses. Codi: AE1049. Curs acadèmic 2015-201

S5 0836+710: An FRII jet disrupted by the growth of a helical instability?

The remarkable stability of extragalactic jets is surprising, given the reasonable possibility of the growth of instabilities. In addition, much work in the literature has invoked this possibility in order to explain observed jet structures and obtain information from these structures. For example, it was recently shown that the observed helical structures in the jet in S5 0836+710 could be associated with helical pressure waves generated by Kelvin-Helmholtz instability. Our aim is to resolve the arc-second structure of the jet in the quasar S5 0836+710 and confirm the lack of a hot-spot (reverse jet-shock) found by present observing arrays, as this lack implies a loss of jet collimation before interaction with the intergalactic medium. In this work, we use an observation performed in 2008 using EVN and MERLIN. The combined data reduction has provided a complete image of the object at arc-second scales. The lack of a hot-spot in the arc-second radio structure is taken as evidence that the jet losses its collimation between the VLBI region and the region of interaction with the ambient medium. This result, together with the previous identification of the helical structures in the jet with helical pressure waves that grow in amplitude with distance, allow us to conclude that the jet is probably disrupted by the growth of Kelvin-Helmholtz instability. This observational evidence confirms that the physical parameters of jets can be extracted using the assumption that instability is present in jets and can be the reason for many observed structures. Interestingly, the observed jet is classified as a FRII object in terms of its luminosity, but its large-scale morphology does not correspond to this classification. The implications of this fact are discussed.Comment: Accepted for publication in Astronomy & Astrophysic

High-Frequency Polarization Variability from Active Galactic Nuclei

The linear polarization of non-thermal emission encodes information about the structure of the magnetic fields, either from the region where the emission is produced (i.e., the intrinsic polarization angle) and/or from the screens of magnetized plasma that may be located on its way towards Earth (i.e., the effect of Faraday rotation). In addition, the variability timescale of the polarized emission, or its Faraday rotation, can be used to estimate the size of the region where the emission (or the Faraday rotation) originates. The observation of polarized emission from active galactic nuclei (AGN) and, in particular, its time evolution, also provides information about the critical role that magnetic fields may play in the process of jet launching and propagation. In this paper, we review some recent results about polarization variability from the cores of AGN jets, including observations at high spatial resolutions and/or at high radio frequencies

LeMMINGs III. The e-MERLIN legacy survey of the Palomar sample: exploring the origin of nuclear radio emission in active and inactive galaxies through the [O III] - radio connection

What determines the nuclear radio emission in local galaxies? To address this question, we combine optical [O III] line emission, robust black hole (BH) mass estimates, and high-resolution e-MERLIN 1.5-GHz data, from the LeMMINGs survey, of a statistically complete sample of 280 nearby optically active (LINER and Seyfert) and inactive [H II and absorption line galaxies (ALGs)] galaxies. Using [O III] luminosity (L[O III]) as a proxy for the accretion power, local galaxies follow distinct sequences in the optical-radio planes of BH activity, which suggest different origins of the nuclear radio emission for the optical classes. The 1.5-GHz radio luminosity of their parsec-scale cores (Lcore) is found to scale with BH mass (Mbh) and [O III] luminosity. Below Mbh ~ 10^(6.5) Msun, stellar processes from non-jetted H II galaxies dominate with Lcore \propto Mbh^(0.62\pm0.33) and Lcore \propto L[O III]^(0.79\pm0.30). Above Mbh ~ 10^(6.5) Msun, accretion-driven processes dominate with Lcore \propto Mbh^(1.5-1.65) and Lcore \propto L[O III]^(0.99-1.31) for active galaxies: radio-quiet/loud LINERs, Seyferts, and jetted H II galaxies always display (although low) signatures of radio-emitting BH activity, with L1.5GHz > 10^(19.8) W Hz^(-1) and Mbh > 10^7 Msun, on a broad range of Eddington-scaled accretion rates (mdot). Radio-quiet and radio-loud LINERs are powered by low-mdot discs launching sub-relativistic and relativistic jets, respectively. Low-power slow jets and disc/corona winds from moderately high to high-mdot discs account for the compact and edge-brightened jets of Seyferts, respectively. Jetted H II galaxies may host weakly active BHs. Fuel-starved BHs and recurrent activity account for ALG properties. In conclusion, specific accretion-ejection states of active BHs determine the radio production and the optical classification of local active galaxies

An approach to the application of additive manufacturing for water environments: a case study to measure dissolved carbon dioxide

This paper describes the design of a case for the grouping and protection of the elements required for the quantification of dissolved carbon dioxide, allowing measurements to a depth of 10 meters. The possibility of implementing additive manufacturing (AM) technologies to reduce the production cost and design capabilities of the system is studied.Peer Reviewe

Numerical simulation of density-driven flow and heat transport processes in porous media using the network method

Density-driven flow and heat transport processes in 2-D porous media scenarios are governed by coupled, non-linear, partial differential equations that normally have to be solved numerically. In the present work, a model based on the network method simulation is designed and applied to simulate these processes, providing steady state patterns that demonstrate its computational power and reliability. The design is relatively simple and needs very few rules. Two applications in which heat is transported by natural convection in confined and saturated media are studied: slender boxes heated from below (a kind of Bénard problem) and partially heated horizontal plates in rectangular domains (the Elder problem). The streamfunction and temperature patterns show that the results are coherent with those of other authors: steady state patterns and heat transfer depend both on the Rayleigh number and on the characteristic Darcy velocity derived from the values of the hydrological, thermal and geometrical parameters of the problems.The first author acknowledges the support of the Universidad Politécnica de Cartagena through a pre-doctoral scholarship and the economic support of the Universidad Católica del Norte to cover the costs to publish in open access

IMS signalling for multiparty services based on network level multicast

3rd EURO-NGI Conference on Next Generation Internet Networks. Norwegian University of Science and Technology, Trondheim, Norway, 21-23 may 2007.The standardization process of the UMTS technology has led to the development of the IP Multimedia Subsystem (IMS). IMS provides a framework that supports the negotiation of the next generation multimedia services with QoS requirements that are envisioned for 3G networks. But even though many of these services involve the participation of multiple users in a multiparty arrangement, the delivery technology at network level is still unicast based. This approach is not optimum, in terms of transmission efficiency. In this paper, a new approach is presented proposing to use a network level multicast delivery technology for the multiparty services that are signalled through IMS. The main advantages and drawbacks related with this new approach are analyzed in the article. Finally, as a starting point in the development of the presented solution, a new SIP signalling dialogue is proposed allowing the negotiation of a generic multiparty service, and supporting at the same time the configuration of the corresponding network level multicast delivery service with QoS requirements that will be used in the user plane.Publicad

Back to the streets: The urban experience in the work of David Hammons

[EN] This presentation explores the implication of the urban experience in the work of the artist David Hammons, as a reference in the context of African American art and as an influential figure in international contemporary art, through the analysis of some of his most outstanding interventions in urban space from the 1980s onwards: Human Pegs Pole Dreams, Bottle Trees, Higher Goals, Path Free, Blizzaard Ball Sale and C#. The interaction of his urban interventions with African ritual traditions in the urban context of Harlem. The correlations with the set of actions that define the urban and its connection with the referents of African-American culture: hidden or invisible narratives, social problems, as well as the inquiry into cultural elements of the African-American context in the Harlem neighborhood. Relation of his artistic proposals with the music of Jelly Roll Morton and with the ideas of cultural creolization, opacity, and poetics of the relationship proposed by Edouard Glissant.[ES] Esta presentación analiza la implicación de la experiencia urbana en la obra del artista afroamericano David Hammons, como artista referente en el contexto del arte afroamericano y como figura influyente en el arte contemporáneo internacional, mediante el análisis de algunas de sus intervenciones mas destacadas en el espacio urbano a partir los años ochenta: Human Pegs Pole Dreams, Bottle Trees, Higher Goals, Path Free y C#. La interacción de sus intervenciones urbanas con las tradiciones rituales procedentes de África en el contexto urbano de Harlem. Las correlaciones con el conjunto de actuaciones que definen lo urbano y su conexión con los referentes de la cultura urbana afroamericana:  narrativas ocultas, problemática social, así como la indagación en elementos culturales propios del contexto afroamericano in barrio de Harlem. Relación de sus propuestas artísticas con la música de Jelly Roll Morton y con la idea de criollización cultural propuesta por Edouard Glissant.Pérez Vidal, I. (2022). De vuelta a las calles: La experiencia urbana en la obra de David Hammons. Editorial Universitat Politècnica de València. 398-405. https://doi.org/10.4995/ANIAV2022.2022.15504OCS39840

Configuración de transporte multicast IP con calidad de servicio en arquitecturas de red con plano de control IMS

El proceso de estandarización de la tecnología UMTS como estándar global 3G ha resultado en el desarrollo del Subsistema Multimedia IP (IP Multimedia Subsystem, IMS). IMS es una arquitectura de control, basada en el protocolo IP, que proporciona un conjunto de funcionalidades que resultan esenciales en la provisión de los servicios multimedia de valor añadido con requisitos de QoS que están previstos en el futuro de las redes móviles de tercera generación. Así, por un lado, IMS provee al usuario con medios para acceder a un amplio rango de servicios implementados mediante Servidores de Aplicación. Por otro lado, las funcionalidades de control de sesión en IMS permiten establecer sesiones multimedia entre Equipos de Usuario (User Equipment, UE), sobre las cuales es posible proporcionar nuevos servicios peer-to-peer basados en el intercambio directo de información entre las partes participantes en el servicio. En este contexto, muchos de los servicios que actualmente están siendo considerados en el futuro de las redes 3G son de naturaleza multiususario, en los que varios usuarios participan en la ejecución del servicio, de modo que la información debe ser intercambiada entre múltiples UEs. Ejemplos de tales servicios son el servicio de Conferencia o el servicio Push-to-talk. Por otro lado, el continuo desarrollo y despliegue de nuevos accesos de banda ancha, posibilita la entrega de nuevos servicios de valor añadido al usuario, lo que finalmente permite atraer la atención del usuario y sostener de este modo el continuo crecimiento de Internet. A este respecto, el desarrollo de especificaciones para una Red de Internet de Próxima Generación permitirá desarrollar nuevas infraestructuras con capacidades y características que soporten la apropiada provisión de los servicios multimedia del futuro sobre las distintas redes de acceso fijas y móviles disponibles. Así, entre las iniciativas más importantes en el campo de las Redes de Próxima Generación (Next Generation Network, NGN), adquiere especial relevancia la propuesta por el grupo TISPAN de ETSI, que trabaja en el desarrollo de especificaciones para una Red de Próxima Generación basada en IMS. Bajo las consideraciones presentadas, el principal objetivo de esta Tesis Doctoral ha consistido en el desarrollo de una plataforma general que, mediante la extensión de las funcionalidades de control de sesión presentes en IMS, soporte la provisión de servicios multiusuario en redes NGN con este plano de control. Asimismo, en la solución presentada, la eficiencia en el uso de los recursos de portadora se ha garantizado mediante el empleo de servicios de transporte multicast a nivel de red en la transmisión de la información de usuario. Por otro lado, se presentarán soluciones que permitan cubrir las carencias presentes en la primera versión de especificaciones de la NGN de TISPAN con respecto a los mecanismos de provisión de calidad de servicio. Finalmente, se realizará una validación de las soluciones presentadas mediante la implementación de las mismas. _____________________________________________The standardization process of the UMTS technology as a 3G global standard, has resulted in the development of the IPMultimedia Subsystem (IMS). IMS is a control architecture, based on the IP protocol, that provides a set of functionalities that are essential in the provision of the value-added multimedia services with QoS requirements that are envisioned in the future of 3G mobile networks. On one hand, IMS provides the user with means to access a wide range of services, implemented by means of Application Servers. On the other hand, the session control functionalities in IMS allow to establish multimedia sessions between User Equipments (UEs), making possible to provide new peer-to-peer services based on the direct exchange of media between the parties that participate in the service. In this context, many of the services that are currently being considered in the future of 3G networks are multiparty in nature, where several users participate in the execution of the service, so that media is exchanged between multiple UEs. Examples of that services are the Conference service or the Push-to-talk service. On the other hand, the continuous development and deployment of new wideband access technologies enables the delivery of new value-added services to the user, which allows to appeal the user attention and to sustain the constant evolution of Internet. In this respect, the development of specifications for a Next Generation Internet network will introduce new infrastructures with features and capabilities to support the future multimedia services over the different fixed and mobile access networks. One of the most relevant initiatives in the field of Next Generation Networks (NGN), is the one proposed by the ETSI TISPAN group, that is currently working in the development of specifications for an IMS based Next Generation Network. Taking into account the previous considerations, the main objective of this PhD thesis has consisted of developing a generic platform that, by extending the IMS session control functionalities, supports the provision of multiparty services in NGN networks with this control plane. In addition, in the presented solution, the efficiency regarding the utilization of bearer resources has been assured by using network level multicast delivery services to transmit the media. On the other hand, solutions will be presented to cover the open issues in the first release of specifications of TISPAN NGN with respect to QoS provisioning. Finally, an experimental validation of the proposed solutions based on implementation will be presented

Modelos de movilidad urbana conectada: impacto Socioeconómico

This document analyzes how urban mobility policies can evolve, based on the study of urban mobility in the STI (Integrated Tariff System) area of the Barcelona region in social and economic terms and proposes tentative urban mobility scenarios for 2030. Based on key parameters of mobility such as shared mobility, the degree of autonomy of the vehicle, aggregate projections are made on the vehicle occupancy rate and the road space occupied by mobility