482 research outputs found
Evaluating air emission inventories and indicators from cruise vessels at ports
This paper provides an estimation of air emissions (CO2, NOX, SOX and
PM) released by cruise vessels at the port level. The methodology is based on the Bfull
bottom-up^ approach and starts by evaluating the fuel consumed by each vessel on the
basis of its individual port activities (manoeuvring, berthing and hoteling). The Port of
Barcelona was selected as the site at which to perform the analysis, in which 125 calls
of 30 cruise vessels were monitored. Real-time data from the automatic identification
system (AIS), factor emissions from engine certificates and vessel characteristics from
IHS Sea-web database were also collected for the analysis. The research findings show
that the most appropriate indicators are inventory emissions per Bport-time gross
tonnage^, Bport-time passenger^ and Bport time^. These emission indicators improve
our understanding of cruise emissions and will facilitate the work that aims to estimate
reliably and quickly the in-port ship emission inventories of cruise ports.Postprint (published version
Beyond the discourses of rating. When reception matters more than consumption. An empirical study about the Colombian television audience
Las mediciones industriales del rating enfrentan desafíos y limitaciones originados por nuevos hábitos de consumo y preferencias de contenidos en ambientes televisivos digitales caracterizados por la globalización, la sobreoferta, la variedad de programación temática y la fragmentación de las audiencias. El presente artículo de investigación presenta los resultados más importantes de la evidencia empírica obtenida a partir de un estudio de orden probabilístico, financiado por el canal privado RCN, que fue aplicado a televidentes colombianos, entre 17 y 60 años, habitantes de los 12 centros urbanos más importantes del país.Rating measurement’ industrial system faces challenges and limits due to new consumption habits and particular content preferences among audiences, in a television environment characterized by globalization, oversupply, thematic programming and audiences’ fragmentation. This research article shows the main results obtained from a quantitative study, of a probabilistic sample, financed by RCN channel, applied to Colombian T.V. audiences, between 17 and 60, who live in the 12 most important urban areas
Interpolation centers' selection using hierarchical curvature-based clustering
It is widely known that some fields related to graphic applications require realistic and full detailed three-dimensional models. Technologies for this kind of applications exist. However, in some cases, laser scanner get complex models composed of million of points, making its computationally difficult. In these cases, it is desirable to obtain a reduced set of these samples to reconstruct the function's surface. An appropriate reduction approach with a non-significant loss of accuracy in the reconstructed function with a good balance of computational load is usually a non-trivial problem. In this article, a hierarchical clustering based method by the selection of center using the geometric distribution and curvature estimation of the samples in the 3D space is described
Estudio de efectos de asimetría en vibradores ultrasónicos axisimétricos
8 pages, 6 figures.-- Comunicación presentada en: XXXV Congreso Español de Acústica – TecniAcústica 2004, IV Congreso Iberoamericano de Acústica, IV Congreso Ibérico de Acústica y EAA Symposium "Environmental and Architectural Acoustics" (Guimaraes, 14-17 Sep 2004).[EN] The use of high-power ultrasonic plate transducers shows a series of problems related with the presence of modal coupling or interactions between the vibrational modes of the ultrasonic system. In such
system, the radiator consists of a stepped circular plate. The radiator plate is driven at its centre by a tuned piezoelectric vibrator generating an axysimetric mode of vibration. Nevertheless, in many cases the nodal figures are deformed and present ovals instead of circles in the plate. This phenomenon which is frequently observed
can be basically due to two main reasons: the material anisotropy and the influence of the high-density of nonaxysimetrical
modes around the operating frequency.This paper deals with the study and analysis of both possibilities using numerical simulations by finite element
techniques and experimental measurements.[ES] El uso de transductores ultrasónicos de potencia del tipo placa vibrante, plantea una serie de problemas relacionados con el posible acoplamiento o interacción entre los diversos modos de vibración que
contiene el sistema. En estos transductores el radiador está constituido por una placa vibrante de geometría circular y perfil escalonado. Esta placa se pone en vibración mediante un excitador piezoeléctrico sintonizado a la frecuencia del modo de vibración de interés. La placa radiante se excita sinusoidalmente en su centro
generando un modo de vibración axisimétrico. Las figuras nodales que se forman son círculos concéntricos. Sin
embargo, en muchos casos aparecen asimetrías en el modo de vibración, de forma que las figuras nodales aparecen deformadas en forma de óvalos. Este fenómeno, que se repite con determinada frecuencia, puede ser debido fundamentalmente a dos causas: la influencia de modos cercanos no axisimétricos o a la anisotropía del
material.En este trabajo se estudian y analizan ambas posibilidades empleando tanto técnicas de simulación numérica por
elementos finitos como medidas experimentales.Este trabajo ha sido financiado con cargo al Proyecto del Plan Nacional de Investigación DPI 2002-3409.Peer reviewe
Los noticieros espejo o la liviandad de la información
Este artículo explora las implicaciones de la falta de contextualización de la informaciónque publican los noticieros de televisión colombianos en la toma de decisiones y laformación de opinión pública en los ciudadanos. Está basado en los resultados de unainvestigación realizada por el Observatorio de Medios de la Facultad de Comunicaciónde la Universidad de La Sabana y el Centro Multimedial de la Universidad Eafit, yfinanciada por la Comisión Nacional de Televisión que, a través de un análisis decontenido, indaga sobre la estructura, cobertura y contenidos de los noticieros de latelevisión en Colombia. El predominio de la noticia escueta, sin contexto o con pocoselementos de éste, termina por desdibujar la función orientadora del periodism
Scaling properties of rainfall and desert dust in the Canary Islands
Precipitation and desert dust event occurrence time series measured in the Canary Islands region are examined with the primary intention of exploring their scaling characteristics as well as their spatial variability in terms of the island's topography and geographical orientation. In particular, the desert dust intrusion regime in the islands is studied in terms of its relationship with visibility. Analysis of dust and rainfall events over the archipelago exhibits distributions in time that obey power laws. Results show that the rain process presents a high clustering and irregular pattern on short timescales and a more scattered structure for long ones. In contrast, dustiness presents a more uniform and dense structure and, consequently, a more persistent behaviour on short timescales. It was observed that the fractal dimension of rainfall events shows an important spatial variability, which increases with altitude, as well as towards northern latitudes and western longitudes
A NEW HIGH-INTENSITY ULTRASONIC TECHNOLOGY FOR FOOD DEHYDRATION
12 páginas, 7 figurasAt present, there is a growing interest in the field of dehydration for preserving food. Ultrasonic energy represents a means to obtain dehydration without affecting the food. This paper deals with an experimental study about the use of high-intensity ultrasound for vegetable dehydration by using a new power ultrasound generator and a procedure in which ultrasonic vibrations are applied in direct contact with the product and under a certain static pressure. The drying effect of this new process is compared with that obtained from forced-air drying assisted by air-borne ultrasonic radiation and from a conventional hot-air drying. The results show that by using the new technology and procedure it is possible to reduce dramatically the treatment time and it is relatively easy to reach a final moisture content in the samples less than 1%. In addition, the product qualities are well preserved, the sample rehydration is higher than 70% and, because of the high efficiency of the new ultrasonic system employed, the energy consumption is low. As a consequence of the results a new technology for industrial applications is under development.Peer reviewe
Climatic change and species modeling of Stevia (Asteraceae) in northwestern Argentina
La elevada biodiversidad y riqueza específica, junto con una gran variedad de ecosistemas, convierten al noroeste de la Argentina (NOA) en un área adecuada para estudiar los posibles efectos del cambio climático sobre la distribución de los organismos. Asteraceae es una familia de plantas con flores bien representada en esta área; en especial, el género Stevia, con 25 especies que habitan diferentes ambientes. Los objetivos de este estudio fueron: 1) modelar la aptitud de hábitat para cinco especies de Stevia que habitan el noroeste argentino, y 2) proyectar dicha aptitud bajo un posible escenario de emisión de gases de efecto invernadero para el año 2050. Se analizaron las especies S. alpina, S. breviaristata, S. minor, S. vaga y S. yaconensis. Los resultados mostraron que, al comparar los mapas basados en condiciones climáticas actuales y futuras, todas las especies de Stevia sufrirían modificaciones en sus rangos de aptitud. Las tendencias observadas en ambos escenarios climáticos futuros son similares, aunque más drásticas en el modelo rcp8.5. El área de aptitud de Stevia alpina, S. breviaristata y S. minor se vería reducida, mientras que la de S. vaga y S. yaconensis aumentaría. Excepto S. minor, las especies presentaron una tendencia principal a migrar del este al oeste, un fenómeno conocido como desplazamiento en altura. Stevia minor sería la especie más afectada en un escenario de mayor emisión de gases; sufriría una reducción mayor a 80% para valores de aptitud superiores a 0.65.The high biodiversity and species richness, along with a great variety of ecosystems, turn northwestern Argentina into an adequate area for study the possible effects of climate change on the distribution of organisms. Asteraceae is a well-represented family of flowering plants in this area; especially, the genus Stevia, with 25 species which inhabit different environments. The goals of this study were: 1) to model habitat suitability for five species of Stevia distributed in northwestern Argentina, and 2) to project such suitability under a possible greenhouse gas emission scenario by 2050. Species S. alpina, S. breviaristata, S. minor, S. vaga and S. yaconensis were analyzed. Results showed that, when comparing maps based on current and future climatic conditions, all Stevia species would undergo changes in their fitness ranges. The trends observed in both future climate scenarios are similar, although they show more drastic consequences in the rcp8.5 model. Stevia alpina, S. breviaristata and S. minor reduce their area of aptitude, while S. vaga and S. yaconensis experience an increase of said area. Except for S. minor, the species showed a major tendency to migrate from East to West, a phenomenon known as altitude shift. Stevia minor would be the more affected species in a higher gas emission scenario since it will suffer a reduction greater than 80% for its suitability values greater than 0.65.Fil: Rodríguez Cravero, Juan Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Grossi, Mariana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División de Plantas Vasculares; ArgentinaFil: Fuentes Castillo, Taryn. Pontificia Universidad Católica de Chile. Facultad de Ciencias Biológicas. Departamento de Ecología; ChileFil: Gutierrez, Diego Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin
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