A comparison of numerical approaches for the design of mooring systems for wave energy converters

This paper analyses the numerical outcome of applying three different well-known mooring design approaches to a floating wave energy converter, moored by means of four catenary lines. The approaches include: a linearized frequency domain based on a quasistatic model of the mooring lines, a time domain approach coupled with an analytic catenary model of the mooring system, and a fully coupled non-linear time domain approach, considering lines' drag and inertia forces. Simulations have been carried out based on a set of realistic combinations of lines pretension and linear mass, subject to extreme environmental conditions. Obtained results provide realistic cost and performance indicators, presenting a comparison in terms of total mooring mass and required footprint, as well as the design line tension and structure offset. It has been found that lines' viscous forces influence significantly the performance of the structure with high pretensions, i.e., >1.2, while there is acceptable agreement between the modelling approaches with lower pretensions. Line tensions are significantly influenced by drag and inertia forces because of the occurrence of snap loads due to the heaving of the floater. However, the frequency domain approach provides an insight towards the optimal design of the mooring system for preliminary designs

Adaptation of web pages of hotels in mobile devices

Mobile devices have become an essential element for users. This fact cannot go unnoticed by brands and business participants, who see a great opportunity to address consumers, thus fulfilling one of the maxims of marketing, in which these participants must be where the consumers are. In this way, the concept of responsive web is essential, which allows the content of the web pages to be adapted to the mobile device, thus improving the mobile consumer experience. In this context, the touristic offer is considered of special relevance being one of the sectors in which users seek more information and make more purchases through mobile devices. Thus, in this study we have analyzed the adaptation of the websites of the hotels in the province of Cadiz to mobile devices. The results in general are positive, however, it has been shown that the web pages of the hotels have not been fully adapted to these devices yet, highlighting the low visibility and size of the text, as well as the scarce availability of the reservation section in the homepage

Anthropometric data collection of Portuguese children using 3D body scanning: considerations about the scanning booth

This paper presents some considerations regarding the scanning booth used in an anthropometric study done with a 3D body scanning technology. The data collected is part of a Ph.D. study conducted in Textile Engineering at University of Minho in Portugal, which aims to develop clothing for overweight and obese Portuguese children aged 2-11 years, of both genders. The challenges faced during data collection are described, and modifications of the scanning booth are proposed. It is possible to conclude that the importance of the scanning booth is key to an efficient anthropometric data collection, including the growth of this technology in the garment industry, Universities Research Institutes involved with anthropometric studies.info:eu-repo/semantics/publishedVersio

Main topics used in the social communication of immigration NGOs in Spain through the social network Facebook

El objetivo de este estudio es conocer la comunicación de las ONG de inmigración en España a través de su red social oficial de Facebook mediante un análisis de contenido de las publicaciones a través del software Nvivo 11 en la que se identifican a través de categorías y subcategorías cuáles son los principales temas o asuntos tratados. Además, para conocer los temas más utilizados y aquellos que generan mayor actividad o interacción se obtiene el número de publicaciones, así como el número de “likes” y de comentarios para cada categoría y subcategoría. En los resultados se determina una disposición de las ONG a destacar localizaciones concretas donde ocurren problemas de inmigración y un interés de los usuarios en lo referente a los problemas y las consecuencias que tiene el entorno marítimo. Además, se observa en los usuarios una mayor interacción en mensajes positivos que en aquellos referidos a problemas e injusticias. También, los usuarios son más reacios en aquellos temas que requieren de una interacción o una involucración más activa y personal con los inmigrantes como son la acogida, la integración y la participación. Por último, resaltar la importancia de los temas educacionales en la comunicación de las ONG y la preocupación de los usuarios por las mafias en la inmigración.The aim of this study is to learn about the communication of immigration NGOs in Spain through their official social network Facebook through an analysis of the content of the publications through the software Nvivo 11 in which the main topics or subjects dealt with are identified through categories and subcategories. In addition, to know the most used topics and those that generate the most activity or interaction, the number of publications is obtained, as well as the number of likes and comments for each category and subcategory. The results identify a willingness of NGOs to highlight specific locations where immigration problems occur and a user interest in the problems and consequences of the maritime environment. In addition, there is more interaction in positive messages among users than in those related to problems and injustices. Also, the users are more reluctant to discuss issues that require more active and personal interaction or involvement with immigrants, such as reception, integration and participation. Finally, to highlight the importance of educational issues in the communication of NGOs and the concern of users about mafias in immigration

Complete breakdown of the Debye model of rotational relaxation near the isotropic-nematic phase boundary: Effects of intermolecular correlations in orientational dynamics

The Debye-Stokes-Einstein (DSE) model of rotational diffusion predicts that the rotational correlation times $\tau_{l}$ vary as $[l(l+1)]^{-1}$, where $l$ is the rank of the orientational correlation function (given in terms of the Legendre polynomial of rank $l$). One often finds significant deviation from this prediction, in either direction. In supercooled molecular liquids where the ratio $\tau_{1}/\tau_{2}$ falls considerably below three (the Debye limit), one usually invokes a jump diffusion model to explain the approach of the ratio $\tau_{1}/\tau_{2}$ to unity. Here we show in a computer simulation study of a standard model system for thermotropic liquid crystals that this ratio becomes much less than unity as the isotropic-nematic phase boundary is approached from the isotropic side. Simultaneously, the ratio $\tau_2/\eta$ (where $\eta$ is the shear viscosity of the liquid) becomes {\it much larger} than hydrodynamic value near the I-N transition. We have also analyzed the break down of the Debye model of rotational diffusion in ratios of higher order rotational correlation times. We show that the break down of the DSE model is due to the growth of orientational pair correlation and provide a mode coupling theory analysis to explain the results.Comment: Submitted to Physical Review

On the relation between virial coefficients and the close-packing of hard disks and hard spheres

The question of whether the known virial coefficients are enough to determine the packing fraction $\eta_\infty$ at which the fluid equation of state of a hard-sphere fluid diverges is addressed. It is found that the information derived from the direct Pad\'e approximants to the compressibility factor constructed with the virial coefficients is inconclusive. An alternative approach is proposed which makes use of the same virial coefficients and of the equation of state in a form where the packing fraction is explicitly given as a function of the pressure. The results of this approach both for hard-disk and hard-sphere fluids, which can straightforwardly accommodate higher virial coefficients when available, lends support to the conjecture that $\eta_\infty$ is equal to the maximum packing fraction corresponding to an ordered crystalline structure.Comment: 10 pages, 6 figures; v2: discussion about hard-square and hard-hexagon systems on a lattice added; five new reference

Evaluation of WRF mesoscale simulations and particle trajectory analysis for the MILAGRO field campaign

Accurate numerical simulations of the complex wind flows in the Mexico City Metropolitan Area (MCMA) can be an invaluable tool for interpreting the MILAGRO field campaign results. This paper uses three methods to evaluate numerical simulations of basin meteorology using the MM5 and WRF models: statistical comparisons with observations, "Concentration Field Analysis" (CFA) using measured air pollutant concentrations, and comparison of flow features using cluster analysis. CFA is shown to be a better indication of simulation quality than statistical metrics, and WRF simulations are shown to be an improvement on the MM5 ones. Comparisons with clusters identifies an under-representation of the drainage flows into the basin and an over-representation of wind shear in the boundary layer. Particle trajectories simulated with WRF-FLEXPART are then used to analyse the transport of the urban plume and show rapid venting and limited recirculation during MILAGRO. Lagrangian impacts were identified at the campaign supersites, and age spectra of the pollutants evaluated at those same sites. The evaluation presented in the paper show that mesoscale meteorological simulations are of sufficient accuracy to be useful for MILAGRO data analysis.National Science Foundation (U.S.) (Award ATM-0511803)National Science Foundation (U.S.) (Award ATM-0810950)National Science Foundation (U.S.) (Award ATM-0810931)Molina Center for Energy and the Environmen

ADSORPTION ESSAYS OF PALLADIUM IN MODIFIED SILICA GEL WITH THIOURONIUM GROUPS: EXPERIMENTAL AND THEORICAL STUDIES

Indexación: Web of Science; ScieloThe silylant 3-cloropropyltriethoxysilyl was anchored over silica gel in anhydrous conditions in order to react with thiourea to obtain modified silica gel with thiouronium. The aim to obtain an inorganic support that is able to hijack metals from the VIII group such as palladium. The product was characterized by Sbet and FTIR infrared spectroscopy. For the determination of the structure in the modified silica gel NMR spectra of silicon and carbon were preformed in solid state. The coordination form of the modified silica gel to the metal was studied computationally in the context of the DFT theory, using the ADF code. This was a collaborative work with "Fundación Chile" for the recuperation of precious metals from the mining industry.http://ref.scielo.org/gk7rm