3,606 research outputs found

    Analysis of the Behaviour of Biofuel-Fired Gas Turbine Power Plants

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    The utilisation of biofuels in gas turbines is a promising alternative to fossil fuels for power generation. It would lead to significant reduction of CO2 emissions using an existing combustion technology, although significant changes seem to be needed and further technological development is necessary. The goal of this work is to perform energy and exergy analyses of the behaviour of gas turbines fired with biogas, ethanol and synthesis gas (bio-syngas), compared with natural gas. The global energy transformation process (i.e. from biomass to electricity) has also been studied. Furthermore, the potential reduction of CO2 emissions attained by the use of biofuels has been determined, considering the restrictions regarding biomass availability. Two different simulation tools have been used to accomplish the aims of this work. The results suggest a high interest and the technical viability of the use of Biomass Integrated Gasification Combined Cycle (BIGCC) systems for large scale power generation

    The psychosocial portrayals of immigrants in Spanish prime time television fiction (2016-2017)

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    The present research shows the results of an analysis of Spanish entertainment television aired in prime time between 2016 and the first semester of 2017 by the leading Spanish TV networks. The aim is to draw a comparison between immigrants and the natives in violent and health behaviours, personality traits, and also the number of conversation topics used by immigrants compared to the natives. Content research was used for this analysis, where a sample of 723 characters (n723) was taken. The final result shows there are different tendency patterns in the index of victims of violent behaviour being the native the ones with the highest score. No significant statistical differences in other indexes were observed. However, other variables are statistically related to immigrants/ foreigners, such as drug abuse, topics regarding health or politics, and furthermore, immigrants are also prone to have personality traits such as ‘unfair’, ‘seductive’ or ‘perverse’.En el presente artículo se muestran los resultados de una investigación en la que se han analizado las series de televisión españolas emitidas en prime time entre 2016 y el primer semestre 2017 por las principales cadenas generalistas con el objetivo de conocer qué comportamientos violentos y de salud, qué atributos de personalidad y qué grado de riqueza conversacional manifestaban sus personajes inmigrantes/extranjeros en comparación con los autóctonos. El método utilizado en la investigación fue el análisis de contenido en una muestra de un total de 723 personajes (n= 723). Se concluye que existen diferencias tendenciales en el índice de víctima de comportamientos violentos siendo los autóctonos los que mayor puntuación presentan. En el resto de índices no se aprecian diferencias estadísticamente significativas. No obstante, se observa que variables individuales como “consumir drogas”, abordar temas de conversación como salud o política y tener rasgos de personalidad como “injusto”, “seductor” o “perverso” están estadísticamente relacionados con la condición de inmigrante/extranjero

    Gender diversity on boards: Determinants that underlie the proposals for female directors

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    [Abstract] Although the gender composition of corporate boards and the contribution of female directors to corporate governance have been previously analysed, few studies have investigated the factors that may help contribute to increasing the still scarce presence of women on boards. Therefore, using three-stage least squares (3SLS) estimation on a data panel comprising the 100 largest companies in the world according to the 2019 Fortune Global 500 ranking, including data on (re)election proposals for corporate board members, this research aims to analyse the influence of the number of men's nominations, board interlocks, director tenure, geographical area, the sector to which the firms belong, and the relevance of firms on women's nominations for boards of directors. The results show the factors that facilitate the presence of women on boards. In addition, the different influences that remain in the election of female and male directors when considering factors related to the experience, expertise, and networks of directors or the visibility of firms can also be observed. This study contributes to the knowledge of gender diversity on boards, shedding light on the factors that might lead to gender-balanced boards. It could also help companies and policymakers design strategies to build more egalitarian boards

    Reputation, Game Theory and Entrepreneurial Sustainability

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    Abstract: This manuscript provides a novel approach to reputational management as a driver of entrepreneurial sustainability, using game theory to integrate three dimensions of reputation. First, if the entrepreneur perceives reputation as a risk source, the analysis is framed as a prisoner’s dilemma schema that is solved by protecting against reputational threats from entrepreneurial sustainability. Second, if the entrepreneur perceives reputation as a competitive advantage, the analysis is framed as an innovator’s dilemma that is solved by getting reputational opportunities from entrepreneurial sustainability. Third, if reputation is perceived as a strategic asset, the analysis is framed as a coordination game schema that results in the development of a reputational intelligence skill that has the potential to become crucial for success in entrepreneurial sustainability. Consequently, this manuscript provides an original multidisciplinary analysis of reputational management by relating well-known theoretical results from game theory to organizational realities

    Water resources situation at Piracicaba, Capivari and Jundiaí watersheds using a dynamic systems model

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    Utilizou-se modelo desenvolvido em dinâmica de sistemas, especificamente para as Bacias Hidrográficas dos Rios Piracicaba, Capivari e Jundiaí (BH-PCJ), com cinco simulações para 50 anos de horizonte, como ferramenta para auxiliar na gestão dos recursos hídricos. O modelo estimou as ofertas e demandas de água, e a geração de águas residuárias dos diversos consumidores existentes nas BH-PCJ. Realizou-se simulação utilizando-se das taxas de consumo e de oferta existentes em 2004, e as precipitações com os valores médios constantes. Sob essas premissas, foi encontrado que as demandas de água aumentarão cerca de 76%, que aproximadamente 39% do volume de água disponível terá origem no reúso das águas residuárias, a carga contaminante aumentará em 91%. O Índice de Falkenmark mudará de 1.403 m³ habitante-1 ano-1, em 2004, para 734 m³ hab-1 ano-1 em 2054; e o Índice de Sustentabilidade de 0,44 para 0,20. Foram explorados outros quatro cenários: com fator de mudanças nas precipitações anuais de 90 e 110%; considerando vazão ecológica equivalente a 30% da vazão média diária, e sem nenhuma mudança nas taxas dos outros fatores, somente na vazão ecológica e no consumo domiciliar de água. Todos eles mostraram tendência à futura crise nos recursos hídricos nas BH-PCJ.Using a dynamic systems model specifically developed for Piracicaba, Capivari and Jundiaí River Water Basins (BH-PCJ) as a tool to help to analyze water resources management alternatives for policy makers and decision takers, five simulations for 50 years timeframe were performed. The model estimates water supply and demand, as well as wastewater generation from the consumers at BH-PCJ. A run was performed using mean precipitation value constant, and keeping the actual water supply and demand rates, the business as usual scenario. Under these considerations, it is expected an increment of about ~76% on water demand, that ~39% of available water volume will come from wastewater reuse, and that waste load increases to ~91%. Falkenmark Index will change from 1,403 m³ person-1 year-1 in 2004, to 734 m3 P-1 year-1 by 2054, and the Sustainability Index from 0.44 to 0.20. Another four simulations were performed by affecting the annual precipitation by 90 and 110%; considering an ecological flow equal to 30% of the mean daily flow; and keeping the same rates for all other factors except for ecological flow and household water consumption. All of them showed a tendency to a water crisis in the near future at BH-PCJ.Ministério da Ciência e TecnologiaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Instituto Nacional de Ciência e Tecnologia em Engenharia da Irrigação (INCT-EI

    Relativistic two-body currents for one-nucleon knockout in electron-nucleus scattering

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    We present a detailed study of the contribution from two-body currents to the one-nucleon knockout process induced by electromagnetic interaction. The framework is a relativistic mean-field model (RMF) in which bound and scattering nucleons are consistently described as solutions of Dirac equation with potentials. We show results obtained with the most general expression of the two-body operator, in which the intermediate nucleons are described by relativistic mean-field bound states; then, we propose two approximations consisting in describing the intermediate states as nucleons in a relativistic Fermi gas, preserving the complexity and consistency in the initial and final states. These approximations simplify the calculations considerably, allowing us to provide outcomes in a reasonable computational time. The results obtained under these approximations are validated by comparing with those from the full model. Additionally, the theoretical predictions are compared with experimental data of the longitudinal and transverse responses of carbon 12. The agreement with data is outstanding for the longitudinal response, where the contribution from the two-body operator is negligible. In the transverse sector, the two-body current increases the response from 30 to 15%, depending on the approximations and kinematics, in general, improving the agreement with data.Comment: 11 pages, 5 figure

    The Atlántida of Capitalism. The murals of Sert in the decorative programme of New York’s Rockefeller Center

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    New York’s Rockefeller Center is one of most symbolically rich places in the world, although few of its millions of visitors stop to reflect on what its images of power really mean. In the form of an Atlantean mythological allegory, Rockefeller Center was conceived as symbolic propaganda for capitalist, liberal values implicit in both the ‘American Dream’ and the ideology espoused by the Rockefeller family. It embodies the utopia of progress and science that promotes the freedom of the individual and the free movement of capital. Due to ideological clashes –or the vagaries of fate– the Catalan José María Sert was the artist to ultimately complete the most eloquent mural in the main building, a mural which had formerly been painted by Diego de Rivera, and entitled Man at the Crossroads. Sert was a muralist who had previously worked on the scenographic illustration of Manuel de Falla’s Atlántida, capturing some of the motifs that inspired that great cantata based on poetic texts by Jacint Verdaguer. That earlier work is reflected in the lobby of Rockefeller Center’s main building. While Diego de Rivera’s censored frescoes have been studied prolifically, little attention has been paid to Sert’s paradoxical reading of the same subjects. In this article, we analyse the history of the Atlantean Mediterranean literary myth in relation to Spain, the use John D. Rockefeller Jr. made of them in his emblematic urbanistic ensemble, and also the peculiar reading that the Catalan muralist made of these themes of Atlantis in relation to capitalism

    Experimental and Theoretical Brownian Dynamics Analysis of Ion Transport During Cellular Electroporation of E. coli Bacteria

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    Escherichia coli bacterium is a rod-shaped organism composed of a complex double membrane structure. Knowledge of electric field driven ion transport through both membranes and the evolution of their induced permeabilization has important applications in biomedical engineering, delivery of genes and antibacterial agents. However, few studies have been conducted on Gram-negative bacteria in this regard considering the contribution of all ion types. To address this gap in knowledge, we have developed a deterministic and stochastic Brownian dynamics model to simulate in 3D space the motion of ions through pores formed in the plasma membranes of E. coli cells during electroporation. The diffusion coefficient, mobility, and translation time of Ca2+^{2+}, Mg2+^{2+}, Na+^+, K+^+, and Cl^- ions within the pore region are estimated from the numerical model. Calculations of pore's conductance have been validated with experiments conducted at Gustave Roussy. From the simulations, it was found that the main driving force of ionic uptake during the pulse is the one due to the externally applied electric field. The results from this work provide a better understanding of ion transport during electroporation, aiding in the design of electrical pulses for maximizing ion throughput, primarily for application in cancer treatment.Comment: Annals of Biomedical Engineering, 202
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