Lifetime of silica final lenses subject to HiPER irradiation conditions

The goal of the European laser fusion project, is to build an engineering facility for repetitive laser operation (HiPER 4a) and later a fusion reactor (HiPER 4b). A key aspect for laser fusion energy is the final optics. At the moment, it is based on silica transmission lenses located 8 m away from the chamber center. Lens lifetime depends on the irradiation conditions. We have used a 48 MJ shock ignition target for calculations. We have studied the thermo-mechanical effects of ions and X-rays on the lenses. Ions lead to lens melting and must therefore be mitigated. On the other hand, X-rays (~1% of the energy) does not produce either a significant temperature rise or detrimental stresses. Finally, we calculated the neutron flux and gamma dose rate on the lenses. Next, based on a simple model we studied the formation of color centers in the sample, which lead to optical absorption. Calculations show that simultaneous neutron and gamma irradiation does not significantly increase the optical absorption during the expected lifetime of the HiPER 4a facility. Under severe conditions (HiPER 4b), operation above 800 K or lens refreshing by thermal annealing treatments seem to assure adequate behavior.

Providing 30Mbit/s to Spain’s final third. -A techno-economic assessment.

Since the Digital Agenda for Europe released the Europe2020 flagship, Member States are looking for ways of fulfilling their agreed commitments to fast and ultrafast internet deployment. However, Europe is not a homogenous reality. The economic, geographic, social and demographic features of each country make it a highly diverse region to develop best practices over Next Generation Access Networks (NGAN) deployments. There are special concerns about NGAN deployments for “the final third”, as referred to the last 25% of the country’s population who, usually, live in rural areas. This paper assesses, through a techno-economic analysis, the access cost of providing over 30 Mbps broadband for the final third of Spain`s population in municipalities, which are classified into area types, referred to as geotypes. Fixed and mobile technologies are compared in order to determine which is the most cost-effective technology for each geotype. The demographic limit for fixed networks (cable, fibre and copper) is also discussed. The assessment focuses on the supply side and the results show the access network cost only. The research completes a previous published assessment (Techno-economic analysis of next generation access networks roll-out. The case of platform competition, regulation and public policy in Spain) by including the LTE scenario. The LTE scenario is dimensioned to provide 30 Mbps (best effort) broadband, considering a network take-up of 25%. The Rocket techno-economic model is used to assess a ten-year study period deployment. Nevertheless, the deployment must start in 2014 and be completed by 2020, in order to fulfil the Digital Agenda’s goals. The feasibility of the deployment is defined as the ability to recoup the investment at the end of the study period. This ability is highly related to network take-up and, therefore, to service adoption. Network deployment in each geotype is compared with the cost of the deployment in the Urban geotype and broadband expected penetration rates for clarity and simplicity. Debating the cost-effective deployments for each geotype, while addressing the Digital Agenda’s goals regarding fast and ultrafast internet, is the main purpose of this paper. At the end of the last year, the independent Spanish regulation agency released the Spain broadband coverage report at the first half of 2013. This document claimed that 59% and 52% of Spain’s population was already covered by NGAN capable of providing 30 Mbps and 100 Mbps broadband respectively. HFC, with 47% of population coverage, and FTTH, with 14%, were considered as a 100 Mbps capable NGAN. Meanwhile VDSL, with 12% of the population covered, was the only NGAN network considered for the 30 Mbps segment. Despite not being an NGAN, the 99% population coverage of HSPA networks was also noted in the report. Since mobile operators are also required to provide 30 Mbps broadband to 90% of the population in rural areas by the end of 2020, mobile networks will play a significant role on the achievement of the 30 Mbps goal in Spain’s final third. The assessment indicates the cost of the deployment per cumulative households coverage with 4 different NGANs: FTTH, HFC, VDSL and LTE. Research shows that an investment ranging from €2,700 (VDSL) to €5,400 (HFC) million will be needed to cover the first half of the population with any fixed technology assessed. The results state that at least €3,000 million will be required to cover these areas with the least expensive technology (LTE). However, if we consider the throughput that fixed networks could provide and achievement of the Digital Agenda’s objectives, fixed network deployments are recommended for up to 90% of the population. Fibre and cable deployments could cover up to a maximum of 88% of the Spanish population cost efficiently. As there are some concerns about the service adoption, we recommend VDSL and mobile network deployments for the final third of the population. Despite LTE being able to provide the most economical roll-out, VDSL could also provide 50 Mbps from 75% to 90% of the Spanish population cost efficiently. For this population gap, facility based competition between VDSL providers and LTE providers must be encouraged. Regarding 90% to 98.5% of the Spanish population, LTE deployment is the most appropriate. Since costumers in less populated the municipalities are more sensitive to the cost of the service, we consider that a single network deployment could be most appropriate. Finally, it has become clear that it is not possible to deliver 30Mbps to the final 1.5% of the population cost-efficiently and adoption predictions are not optimistic either. As there are other broadband alternatives able to deliver up to 20 Mbps, in the authors’ opinion, it is not necessary to cover the extreme rural areas, where public financing would be required.

Análisis de sistemas eléctricos en microsatélites. Desarrollo de módulos para una Concurrent Design Facility (CDF) para desarrollo y análisis de misiones espaciales = Analysis of microsatellites power subsystems (battery testing). Development and programming of a new Orbit Design Module for a space mission Concurrent Design Facility (CDF)

El presente proyecto se ha realizado durante las prácticas curriculares que han tenido lugar en el Instituto Universitario de Microgravedad “Ignacio Da Riva” (IDR/UPM). A lo largo de estas prácticas se han llevado a cabo trabajos en diversos campos, todos relacionados con el UPMSat-2, desde el subsistema de potencia (placas solares y baterías) hasta el desarrollo de módulos para la Sala de Diseño Concurrente (Concurrent Design Facility, CDF). En la realización de las mismas se ha trabajado en equipo, junto con otros dos alumnos. El objetivo del proyecto es recopilar las tareas realizadas, proporcionando el desarrollo teórico necesario para llevar a cabo todas ellas. Al ser un trabajo con varias partes claramente diferenciadas, se ha optado por comenzar con unas páginas dedicadas a las misiones espaciales. A continuación el trabajo se adentra en el subsistema de potencia de un satélite, particularizando para el UPMSat-2. Finalmente, se proporciona la teoría necesaria para el desarrollo del módulo de misión de la CDF del IDR/UPM, software que se ha desarrollado y tiene reservado un espacio al final, en el cual se describe el programa y se realizan comparaciones de los resultados que proporciona frente a casos reales.