173 research outputs found
MATLAB. Introducción a las operaciones con matrices
Guía básica para operar con MATLAB y realizar operaciones con matrice
Ajustes de modelos y operaciones con matrices en EXCEL
Se muestran algunas utilidades de las hojas de cálculo de Excel para ajustar series de datos a modelos matemáticos sencillos y cómo utilizar modelos matriciales con esta misma finalidad
Viability study of sailing propulsion combined with a conventional system
For many years now, sails have been used as a propulsion system. At present, they are restricted to recreational/sport crafts since the appearance of the first steam vessels in the beginning of the 19 th century. But in the last years, due to the increase of fuel price and the pollution of the environment, it is being studied the possibility to introduce again the sail as a propulsive method combined with other conventional systems. In this paper, it is studied the viability of using a sail as a propellant with other conventional systems of propulsion. After considering the concept of apparent wind, the range of use of this complementary propulsion is presented. The calculation methodology, the numerical simulations and the wind inputs from a specific route are also included
A contribution to appendage drag extrapolation using computational tools
In this paper, the foundations of the beta method, widely used in todays ship appendage extrapolations, are explored. The present work pretends to validate the Beta Method using experimental and computational tools. The ship used is a rounded bow tugboat with two significant appendages, namely, a midship protective structure for the propulsion system and a stern keel. The experimental and computational data was obtained through Towing Tank trials and a RANSE CFD code, respectively
EU-CargoXpress: wind propulsion concept
The EU-CargoXpress project suggests the usage of sustainable energies to reduce the fuel consumption. The updated concept consists of hoisting the superstructure and using it as a sail together with the conventional propulsion. This paper presents the study of the sail performance by means of a computational analysis and wind tunnel tests. Moreover, a research of the energy saving in different operational areas has been conducted. It is concluded that there is a significant energy saving by using the superstructure as a sail which leads to a reduction of fossil fuel consumption and consequently, a reduction of greenhouse gas emissions
El Buque de Cooperación Pesquera, una iniciativa de la Admisnitración para la pesca responsable y sostenible
El pasado año 2007, Astilleros Armón-Vigo ganó un Concurso de la Secretaría General de Pesca Marítima del antiguo Ministerio de Agricultura, Pesca y Alimentación cuyo objeto era el Proyecto y Construcción de un Buque para la Cooperación Pesquera. El buque deberá tener medios propios para la cooperación al desarrollo y para la formación de los pescadores y trabajadores de las Empresas e Instituciones radicadas en el exterior, en aquellas operaciones relacionadas tanto con la propia actividad pesquera, como con la actividad transformadora, conservera y comercializadora. Esta es una acción novedosa - quizás la primera de estas características que se realiza en el mundo - y con ella se hace patente el apoyo decidido y la apuesta clara que la Administración Pesquera Española quiere hacer, de manera no exclusiva pero si prioritaria, para ayudar a aquellos países con los que se firmen Acuerdos y/o Convenios de Cooperación para el Desarrollo Pesquero de aquellos. Se trata de en un buque de diseño moderno, socialmente avanzado en las habilitaciones de la tripulación y optimizado hidrodinámicamente para poder rentabilizar al máximo su utilización, de tal manera que pueda desplazarse, con velocidad suficiente, a lo largo del año a aquellos países de cualquier continente que, por las necesidades de la cooperación pesquera y/o de nuestras empresas así lo demanden. Este buque, deberá llevar, en una o en distintas cubiertas, aquella maquinaria de última generación utilizada por nuestras industrias (conserveras, transformadoras, elaboradoras, comercializadoras de productos pesqueros tanto frescos como congelados, etc.), que se encuentran radicadas en el exterior, para formar personal en aquellos procesos que necesiten cualificar mano de obra especializada, reproduciendo aquellos procedimientos necesarios para mantener la actividad y la rentabilidad de las mismas. Por último, el buque deberá estar provisto de dos laboratorios: uno oceanográfico y otro biológico, dotados de tecnología punta para la formación en investigación científica a nivel elemental y medio, adaptados para la formación y para las necesidades científicas en la que es conveniente instruir a los países en vías de desarrollo para poder cualificar a sus técnicos en esos niveles. Estos laboratorios estarán preparados también para la formación básica en el marisqueo y la acuicultura.
In the last year, ARMON-VIGO shipyard won the contest to design and to built a ship for the fishing cooperation promoted by the General Secretary of Maritime Fisheries belong to the old Ministry of Agriculture, Fishing and Food. The ship must have any facilities for the cooperation and development for the education and training of the fishermen and workers in the companies and Institutions related not only with the fishing activity but with transformation, canning and commercial activities also. This can be considered as a novelty, maybe the first one of these characteristics in the world. It represents the strong support and the clear position of the Spanish Fishing Administration, not exclusively but with an significant priority to help to those countries which sign Agreements of Fishing Development and Cooperation with Spain. It would be a ship of modern design, with a very high standard for the crew accommodation and special attention to the hydrodynamic aspects in order to optimize the hydrodynamic performance through the different actions with countries all around the world and following also the necessities of our own companies. The ship must incorporate in the different decks all the machinery and equipment of the last generation used by our industries located in other countries in order to educate and to train the personnel in the special processes that require a qualified manpower. It is necessary to reproduce all the processes in order to maintain the activity and the profitability of these companies. At the end, the ship must include two laboratories: one oceanographic and other biologic, provided with the highest technology for the training in scientific research at an elemental and medium level appropriated to the countries under development to which they are dedicated. A goal is to qualify the technicians of these countries in an appropriate level. These laboratories are also prepared for training in acuculture and shellfising
Star-formation histories of local luminous infrared galaxies
We present the analysis of the integrated spectral energy distribution (SED)
from the ultraviolet (UV) to the far-infrared and H of a sample of 29
local systems and individual galaxies with infrared (IR) luminosities between
10^11 Lsun and 10^11.8 Lsun. We have combined new narrow-band H+[NII]
and broad-band g, r optical imaging taken with the Nordic Optical Telescope
(NOT), with archival GALEX, 2MASS, Spitzer, and Herschel data. The SEDs
(photometry and integrated H flux) have been fitted with a modified
version of the MAGPHYS code using stellar population synthesis models for the
UV-near-IR range and thermal emission models for the IR emission taking into
account the energy balance between the absorbed and re-emitted radiation. From
the SED fits we derive the star-formation histories (SFH) of these galaxies.
For nearly half of them the star-formation rate appears to be approximately
constant during the last few Gyrs. In the other half, the current
star-formation rate seems to be enhanced by a factor of 3-20 with respect to
that occured ~1 Gyr ago. Objects with constant SFH tend to be more massive than
starbursts and they are compatible with the expected properties of a
main-sequence (M-S) galaxy. Likewise, the derived SFHs show that all our
objects were M-S galaxies ~1 Gyr ago with stellar masses between 10^10.1 and
10^11.5 Msun. We also derived from our fits the average extinction (A_v=0.6-3
mag) and the polycyclic aromatic hydrocarbons (PAH) luminosity to L(IR) ratio
(0.03-0.16). We combined the A_v with the total IR and H luminosities
into a diagram which can be used to identify objects with rapidly changing
(increasing or decreasing) SFR during the last 100 Myr.Comment: 16 pages + online material, accepted for publication in A&
Aerosol analysis by micro laser-induced breakdown spectroscopy: A new protocol for particulate matter characterization in filters
Atmospheric aerosols (particulate matter – PM) affect the air quality and climate, even in remote areas, such as the Antarctic Region. Current techniques for continuous PM monitoring are usually complex, costly, time consuming and do not provide real-time measurements. In this work, based on micro laser-induced breakdown spectroscopy (LIBS), an innovative method with an optical design and multi-elemental scanning imaging, is presented to characterize PM collected in filters from Antarctica. After following a simple protocol and under atmospheric pressure, the new approach allows to obtain a global visualization of the elemental PM composition of the filters with a minimum sample destruction and preparation. For the first time, we were able to map the localization of pollutants in filters at high spatial resolution and speed. This recent method offers a new insight on the characterization of PM, particularly in isolated areas, where no complex equipment and real time measurements are demanded
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