Preface to the special issue on the European Hydrogen Energy Conference 2018, EHEC2018, Malaga, Spain

Since 2005, the European Hydrogen Energy Conferences (EHECs) have provided an international interdisciplinary forum devoted to hydrogen and related technologies. EHEC2018 was held in Malaga, Spain from 14th to 16th March 2018. It was organized by the Spanish Hydrogen Association with the support and collaboration of the European Hydrogen Association, Hydrogen Europe, the International Hydrogen Energy Association, the International Journal of Hydrogen Energy and Hydrogen Europe Research. EHEC2018 was a great success as the main goals of an EHEC were fully accomplished: dissemination and promotion of the use of hydrogen technologies; sharing of the new research and business advances with society; presentation and discussion of the most innovative research in hydrogen and fuel cell technologies; and encouragement of the exchange of scientific and technical information between the different actors in the H2-related sector. Some 400 participants from 34 countries attended EHEC2018 and contributed to its success. Plenary presentations at the conference addressed representative developments in: fuel cell electric vehicles and hydrogen infrastructures; H2 and fuel cell national initiatives, strategies and legislation; and new hydrogen opportunities and challenges. A total of 150 oral presentations in 6 parallel sessions, together with 100 poster communications covered the main topics in the field of hydrogen, fuel cells and the related technologies. There were specific sessions devoted to economic and environmental aspects, public strategies and the presentation of European projects..

Design and manufacture of a high-temperature PEMFC and its cooling system to power a lightweight UAV for a high altitude mission

In the present study, the optimal design of a high-temperature proton exchange membrane fuel cell (HT-PEMFC) that will be used to power an unmanned aerial vehicle (UAV) in a high altitude mission is performed. The use of PEMFCs for service ceiling above 10 km implies overcoming a number of problems caused by the harsh environmental conditions. Among them, new strategies to manage the heat generated by electrochemical reactions are needed. The maximum power required by the UAV was determined solving the aerodynamic problem, and the design of the lightweight HT-PEMFC, including its cooling system, was optimized. To perform the numerical solution of the heat transfer problem, a computational code was implemented using the EES software. The decisions adopted resulted in a 40-cells stack with an electric power above 1 kW and a weight around 3.65 kg. Besides, it is demonstrated that, for the configuration considered in the study, a passive cooling system without any additional fan system can be used to maintain the stack temperature in 160 °C

Respuesta dinámica de un edificio considerando el efecto de interacción suelo-estructura

En esta monografía se presenta el análisis de un edificio de 12 niveles de elementos prefabricados en la ciudad de Ensenada donde se determina la respuesta dinámica considerando al edificio apoyado en base rígida y teniendo en cuenta el efecto de interacción suelo-estructura, en el cual se considera a la estructura apoyada en suelo blando. Se lleva a cabo un análisis lineal para evaluar la respuesta dinámica de la estructura bajo condiciones de cargas gravitacionales establecidas en un reglamento mexicano, específicamente, en el Capítulo 5 y 6 de las Normas Técnicas Complementarias sobre Criterios y Acciones para el Diseño Estructural de las Edificaciones del DF (2004). Se realiza la obtención y distribución de las fuerzas sísmicas laterales de la estructura apoyada en base rígida utilizándose los criterios de diseño y análisis estructural del Capítulo 9 de las Normas Técnicas Complementarias para Diseño por Sismo del DF (2004), que corresponden al análisis dinámico modal. La respuesta del edificio producida por el efecto de interacción suelo-estructura se determina aplicando el método mencionado en el apéndice A de estas mismas normas. Se evalúa la respuesta de sitio donde se recurre al uso de la vibración ambiental y posteriormente, mediante el método de Nakamura, se obtiene el periodo predominante del suelo necesario para estimar la relevancia del efecto de interacción suelo-estructura. En el transcurso de esta monografía, se presentan estudios de algunos autores sobre la consideración y consecuencias del efecto de interacción suelo-estructura en el análisis sísmico de edificios. Además se muestran los procedimientos a seguir para determinar la respuesta dinámica de la estructura en estudio con base rígida y considerando el efecto de interacción suelo-estructura. También se presentan las distorsiones de entrepiso, que se determinan a partir de los desplazamientos relativos de cada nivel, para la estructura con base rígida y considerando el efecto de interacción suelo-estructura. Por último se hizo la comparación de ambas distorsiones con los valores máximos permitidos de las Normas Técnicas Complementarias para Diseño por Sismo del DF (2004) establecidos en la sección 1.8 y apéndice A.4.Postprint (published version

Novel use of green hydrogen fuel cell-based combined heat and power systems to reduce primary energy intake and greenhouse emissions in the building sector

Achieving European climate neutrality by 2050 requires further efforts not only from the industry and society, but also from policymakers. The use of high-efficiency cogeneration facilities will help to reduce both primary energy consumption and CO2 emissions because of the increase in overall efficiency. Fuel cell-based cogeneration technologies are relevant solutions to these points for small- and microscale units. In this research, an innovative and new fuel cell-based cogeneration plant is studied, and its performance is compared with other cogeneration technologies to evaluate the potential reduction degree in energy consumption and CO2 emissions. Four energy consumption profile datasets have been generated from real consumption data of different dwellings located in the Mediterranean coast of Spain to perform numerical simulations in different energy scenarios according to the fuel used in the cogeneration. Results show that the fuel cell-based cogeneration systems reduce primary energy consumption and CO2 emissions in buildings, to a degree that depends on the heat-to-power ratio of the consumer. Primary energy consumption varies from 40% to 90% of the original primary energy consumption, when hydrogen is produced from natural gas reforming process, and from 5% to 40% of the original primary energy consumption if the cogeneration is fueled with hydrogen obtained from renewable energy sources. Similar reduction degrees are achieved in CO2 emissions

Energy value of unfermented dried grape pomace as substitute of alfalfa hay in diets for growing lambs

The energy value of unfermented dried grape pomace (DGP) was evaluated in an 84 d feeding trial on 16 Pelibuey×Dorper lambs (17.8 ± 2.0 kg). The control diet contained 90% mature alfalfa hay and 10% concentrates. Treatments consisted in the replacement (DM basis) of alfalfa hay by DGP at 0, 10, 20 or 30%. Lambs were blocked by weight and assigned individually to pens. Increasing DGP level in diet tended (P=0.06) to decrease daily gain and linearly increased (P=0.04) dry matter intake (DMI); thus, feed efficiency, dietary energy, and observed-to-expected diet NE were linearly decreased (P<0.01), increasing linearly (P<0.01) observed-to-expected DMI coefficient as DGP level was increased in the diet. There were no effects of treatments on carcass characteristics. Using the replacement technique, the energy value of DGP were 0.80, 0.75 and 0.67 Mcal ENm/kg DM, for 10, 20 and 30% of inclusion, respectively. It is concluded that the estimated NE of DGP at 10% inclusion level in the diet is very similar to the NE value assigned by the NRC (2007) for the fermented DGP. Increasing the inclusion of DGP levels beyond 10% decreases its energy value, maybe due to the negative associative effects of chemical compounds (such as phenols) naturally contained in DGP

Review—meta-review of fire safety of lithium-ion batteries: industry challenges and research contributions

The Lithium-ion battery (LIB) is an important technology for the present and future of energy storage, transport, and consumer electronics. However, many LIB types display a tendency to ignite or release gases. Although statistically rare, LIB fires pose hazards which are significantly different to other fire hazards in terms of initiation route, rate of spread, duration, toxicity, and suppression. For the first time, this paper collects and analyses the safety challenges faced by LIB industries across sectors, and compares them to the research contributions found in all the review papers in the field. The comparison identifies knowledge gaps and opportunities going forward. Industry and research efforts agree on the importance of understanding thermal runaway at the component and cell scales, and on the importance of developing prevention technologies. But much less research attention has been given to safety at the module and pack scales, or to other fire protection layers, such as compartmentation, detection or suppression. In order to close the gaps found and accelerate the arrival of new LIB safety solutions, we recommend closer collaborations between the battery and fire safety communities, which, supported by the major industries, could drive improvements, integration and harmonization of LIB safety across sectors

La enfermedad periodontal inflamatoria crónica en jóvenes de la Provincia de Villa Clara

Periodontal diseases are among the most common ailments that affect adolescents and young people. In order to describe chronic inflammatory periodontal disease in young people from 18 to 20 years of the Province of Villa Clara, it is conducted a cross-sectional descriptive study from January to December 2013; 510 youths of both sexes and from all municipalities were studied. The variables included in the study were age, sex, educational level, race, place of residence and periodontal condition. To determine the severity prevalence of periodontal disease the periodontal index was used in its revised form. The prevalence of periodontal disease was high and, in relation to gravity, moderate gingivitis; between the severity of chronic inflammatory periodontal disease the race, the average educational level and area of residence were not found significant differences.Las enfermedades periodontales se encuentran entre las dolencias más frecuentes que afectan a los adolescentes y a los jóvenes. Con el objetivo de describir la enfermedad periodontal inflamatoria crónica en jóvenes de 18 a 20 años de la Provincia de Villa Clara se realizó un estudio descriptivo transversal de enero a diciembre del año 2013; se estudiaron 510 jóvenes de ambos sexos y de todos los municipios. Las variables incluidas en el estudio fueron la edad, el sexo, el nivel educacional, la raza, el lugar de residencia y la condición periodontal. Para determinar la prevalencia gravedad de la enfermedad periodontal se utilizó el índice periodontal en su forma revisado. La prevalencia de la enfermedad periodontal fue alta, con relación a la gravedad la gingivitis moderada, entre la gravedad de la enfermedad periodontal inflamatoria crónica la raza, el nivel educacional medio y la zona de residencia no se encontraron diferencias significativas

Simón Bolívar's Republic: a bulwark against the "Tyranny" of the Majority

Based on Bolívar's speeches, decrees, and correspondence as well as on Gran Colombia's constitutions and laws, this essay examines the tensions within Bolívar's vision of Venezuela's and New Granada's society produced by his republican, yet authoritarian and hierarchical ideas, his concern for keeping the lower classes of African descent in check, and his denial of Indian agency. It shows that even in Peru, Bolívar's main concern was to prevent the racial war and social disintegration that allegedly slaves and free Afro-descended people would bring to the newly independent nations. To prevent such an outcome, he advocated all along legal equality through the abolition of the colonial privileges and, since mid-1816, the abolition of slavery, but simultaneously the preservation of the monopole of power by the white creole elite. He secured the perpetuation of the socioracial hierarchy inherited from Spain by a two-edged citizenship: an active citizenship restricted to a tiny literate and skilled minority and an inactive citizenship for the immense majority of (mostly nonwhite) men

Diversity and ethics in trauma and acute care surgery teams: results from an international survey

Background: Investigating the context of trauma and acute care surgery, the article aims at understanding the factors that can enhance some ethical aspects, namely the importance of patient consent, the perceptiveness of the ethical role of the trauma leader, and the perceived importance of ethics as an educational subject. Methods: The article employs an international questionnaire promoted by the World Society of Emergency Surgery. Results: Through the analysis of 402 fully filled questionnaires by surgeons from 72 different countries, the three main ethical topics are investigated through the lens of gender, membership of an academic or non-academic institution, an official trauma team, and a diverse group. In general terms, results highlight greater attention paid by surgeons belonging to academic institutions, official trauma teams, and diverse groups. Conclusions: Our results underline that some organizational factors (e.g., the fact that the team belongs to a university context or is more diverse) might lead to the development of a higher sensibility on ethical matters. Embracing cultural diversity forces trauma teams to deal with different mindsets. Organizations should, therefore, consider those elements in defining their organizational procedures. Level of evidence: Trauma and acute care teams work under tremendous pressure and complex circumstances, with their members needing to make ethical decisions quickly. The international survey allowed to shed light on how team assembly decisions might represent an opportunity to coordinate team member actions and increase performance