Underwater Wireless Communications in Freshwater at 2.4 GHz

Publisher copyright and source must be acknowledged with citationThere are few equations for underwater communications in the related literature. They show that the speed propagation and absorption coefficient in freshwater are independent of the working frequency of the transmitted signals. However, some studies demonstrate that electromagnetic waves present lower losses when they are working at certain frequencies. In this paper, we perform a set of measurements of electromagnetic (EM) waves at 2.4 GHz in the underwater environment. In our study case, we fix the water conditions and we measure the behavior of EM as a function of several network parameters such as the working frequency, data transfer rates and modulations. Our results will show that higher frequencies do not mean worse network performance. We will also compare our conclusion with some statements extracted from other works.This work has been partially supported by the Ministerio de Ciencia e Innovacion, through the Plan Nacional de I+D+i 2008 - 2011 in the Subprograma de Proyectos de Investigacion Fundamental, project TEC2011 - 27516, and by the Polytechnic University of Valencia, through the PAID-05-12 multidisciplinary projects, Ref: SP20120420. This work has also been partially supported by the Instituto de Telecomunicacoes, Next Generation Networks and Applications Group (NetGNA), Portugal, and by National Funding from the FCT Fundacao para a Ciencia e a Tecnologia through the PEst - OE/EEI/LA0008/2013 Project.Sendra Compte, S.; Lloret, J.; Rodrigues, JJPC.; Aguiar, JM. (2013). Underwater Wireless Communications in Freshwater at 2.4 GHz. IEEE Communications Letters. 17(9):1794-1797. https://doi.org/10.1109/LCOMM.2013.072313.131214S1794179717

Los mayores y las nuevas tecnologías de la comunicación

[Resumen] Fundamentos: En una sociedad envejecida es necesario establecer nuevas alternativas que de alguna manera traten de satisfacer las necesidades de las personas mayores, a la vez que incrementen su calidad de vida percibida. En este sentido, las nuevas tecnologías, como la informática, se han convertido en una herramienta básica de nuestra sociedad, de la que los mayores, sin ninguna duda, podrán beneficiarse. El objetivo del presente trabajo es conocer la opinión de los mayores acerca de temas relacionados con la informática e Internet, así como su capacidad de acceso a las nuevas tecnologías y los conocimientos con los que cuentan. Métodos: Se realiza una entrevista estandarizada, de diseño propio, a una muestra de 105 personas mayores con una edad media de 73 años, residentes en la ciudad de A Coruña. Resultados: De los resultados obtenidos se constata que aunque la mayoría de las personas mayores no cuenta con ordenador personal ni ha trabajado con aplicaciones informáticas, les gustaría aprender más sobre este campo. Además, cuando se conectan a Internet lo hacen desde centros sociales y/o educativos, no encontrando excesivos problemas en su manejo y navegación. Conclusiones: Es necesario fomentar el uso de la informática por parte de los mayores, ya que en un futuro puede constituir una herramienta imprescindible en la intervención sobre problemas inherentes al envejecimiento como son el aislamiento o la soledad entre otros.[Abstract] new alternatives, that somehow try to satisfy the needs of elderly people and that at the same time increase their quality of life. On this sense, the new technologies, such as computer science, have become a basic tool of our society, and the elderly, without no doubt will be able to benefit from it. The objective of the present work is to know what the elderly think about themes related to computer science and internet, as well as their capacity of accessing to new technologies, and the knowledge that they have about them. Methods: A standarized interview has been made, it´s self designed, to a sample of 105 elderly people living in the city of A Coruña. Results: Although most elderly people don´t have a personal computer neither have worked with a computer application, would like to learn more about this field. When they are connected to internet they do it from social and/or educative centres, not having great problems neither in its handling or navigation. Conclusions: It´s necessary to promote the use of computer science on the elderly people, since in a future it can constitute an essential tool in the intervention on inherent problems to aging such as isolation or loneliness among others

In situ measurement of hydraulic conductivity of mountain soils: a case study in Serra da Estrela mountain (Central Portugal)

Understanding the role of the vadose zone is essential to accurately assess hydrogeological systems and the respective groundwater resources. The study area (Manteigas – Nave de Santo António – Torre sector, Serra da Estrela Mountain, Central Portugal) presents specific geological, morphotectonical and climatic characteristics with significant influence on the hydrogeologic regime. The vadose zone has particular features that contribute to control both the quantity and the quality of the groundwater resources. In situ hydraulic conductivity tests were carried out in A and H soil horizons, by means of the constant head permeameter (Guelph permeameter) method. The mean value of the field saturated hydraulic conductivity is high (around 6 cm/h) and is typical of coarse textured soils. Unsaturated hydraulic conductivity was estimated using the Gardner mathematical model

Insecticidal activity of the petroleum ether extract of ageratum conyzoides l.

Se estableció que el extracto de éter de petróleo (pe 40-60"') de Ageratum conyzoides L. presenta fuerte actividad insecticida contra larvas de tercer estadio de Musca domestica (Díptera), contra larvas de tercer, cuarto y quinto estadio de Cynthia carye (Lepidoptera) y contra individuos adultos de Acanthoscelides obtectus (Coleóptera). En esta acción insecticida podrían estar involucrados dos flavonoides conocidos que se aislaron de este extracto: eupalestina y lucidina dimetiléter. También se aisló prococeno II, cromeno éste que demostró ser altamente tóxico contra larvas de M. domestica cuando las pruebas de contacto se hicieron irradiando con luz solar. En cambio, no mostró ningún efecto cuando los ensayos se hicieron en la oscuridad o bajo irradiación de luz UV

Estudo hidrogeológico de uma área montanhosa (Serra da Estrela,Portugal central): uma abordagem multidisciplinar

The results ofa preliminary hydrogeological study ofthe river Zêzere catchment upstream ofManteigas(Serra da Estrela Natural Park,Central Portugal) are presented.In this mountain region,different types of groundwater and surface water (used in several economic activities) occur.The methodology adopted in thisstudy emphasizes the way how Geology,Geomorphology,Geophysics,Geochemistry,Soil Science andHydrogeology contribute to the description ofthe hydrological phenomena taking place in the catchment,such as infiltration and aquifer recharge and groundwater flow and geochemistry — allowing to develop bet-ter hydrogeologic conceptual models.The hydrological modelling in course includes the use ofthe VISU- AL BALAN code,which is being coupled to a GIS.The hydrogeochemical techniques are highlighted as well as its preliminary results concerning major and minor elements.The thermomineral water study includes the identification ofthe reservoir’s geologic material,the characterization ofwater-rock interactionand geothermometry.info:eu-repo/semantics/publishedVersio

Design and testing of a microchannel reactor for the PROX reaction

The different steps for manufacturing a microchannel reactor for the PROX reaction are discussed. Transient Liquid Phase bonding (TLP) using a Ni-B-Si amorphous melt spun is used for joining micromilled Al-alloyed ferritic stainless steel plates followed by recrystallization at 1200°C for 5h. A CuOx-CeO2 catalyst synthesized by the coprecipitation method was washcoated on the microchannel block resulting in a homogenous 20-30μm thick layer. The catalytic activity for CO-PROX reaction is similar in both the powder catalyst and the microchannel coated reactor but the selectivity is higher in the microchannel reactor. © 2010 Elsevier B.V.Ministerio de Ciencia e Innovación MAT-2006-12386-C05, ENE-2009-14522-C05-01, BES-2007-14409, BES-2007-15297Junta de Andalucía P06-TEP-0848