Search results for "Power"
showing 10 items of 5099 documents
“Cognitive Economic Geography” – Evolution of Regional Strategies
2013
Abstract The aim of this article is to present the role of cognitive approach in economic geography and regional innovation strategies based on theory evolution as well as the case of regional development strategies evolution for an old industrial region in emerging economic spaces.
A new application for nickel foam in alkaline fuel cells
2009
The use of nickel foam as an electrode substrate in alkaline fuel cells (AFCs) has been investigated for bi-polar cells incorporating an electrically conducting gas diffusion layer. This contribution focuses on the cathode, and draws comparisons between nickel foam and nickel mesh substrates. One of the principal electrocatalysts for the cathodic reduction of oxygen is silver, so an improvement in electrochemical performance was obtained by electroplating the nickel foam with silver. The electrodeposition process was optimised to maximise electrochemical performance with a minimum of silver deposited. Nickel foam, which is less expensive than the usual nickel mesh, appears to be a good subs…
Oxidative dehydrogenation of ethane: A study over the structure and robustness of Ni–W–O catalysts
2014
[EN] The robustness of one selected Ni-W-O catalyst has been studied in the oxidative dehydrogenation of ethane. This catalyst initially deactivates for the first 10 h online decreasing 15% of its catalytic activity compared to its initial stable catalytic activity. However from 10 to 60 h online the catalytic activity keeps almost stable. On the other hand, it has been shown that the Ni-W-O catalyst cannot tolerate an oxygen-free atmosphere (C-2 and He) as nickel oxide is transformed into metallic nickel. Methane and hydrogen as well as abundant coke were formed on the surface of the catalyst in these O-free conditions. However a re-calcination in air leads to the removal of coke, the cata…
Influence of radiation defects on tritium release parameters from Li2O
1998
Abstract The study of the influence of radiation defects on tritium release behavior from polycrystalline Li2O was performed by simultaneous measurements of the luminescence emission and tritium release. It was found that the radiation defects in Li2O introduced by electron irradiation cause the retention of tritium. It is thought that the tritium recovery is affected by the formation of a Li–T bond, which is tolerant of high temperatures. The retardation of tritium decreases with increasing absorbed dose in the dose range from 50 to 140 MGy. The aggregation of radiation defects at high irradiation doses is considered to be responsible for the decrease of the interaction of tritium with rad…
Novel method for determination of tritium depth profiles in metallic samples
2019
Tritium accumulation in fusion reactor materials is considered a serious radiological issue, therefore a lot of effort has been concentrated on the development of radiometric techniques. A novel method, based on gradual dissolution, for the determination of the total tritium content and its depth profiles in metallic samples is demonstrated. This method allows for the measurement of tritium in metallic samples after their exposure to a hydrogen and tritium mixture, tritium containing plasma or after irradiation with neutrons resulting in tritium formation. In this method, successive layers of metal are removed using an appropriate etching agent in the controlled regime and the amount of evo…
Metrological performances of voltage and current instrument transformers in harmonics measurements
2018
In the new electrical system scenario, the increasing presence of non-linear loads and renewable energy sources makes the measurement of harmonics an essential task. The accuracy of harmonic measurement firstly depends on the used instrument transformers for voltage and current sensing. Since the behavior of instrument transformers in non-sinusoidal conditions is not always well defined, this paper presents an experimental study on the metrological performances of current and voltage instrument transformers (CTs and VTs) in the presence of harmonics. Proper tests procedures are defined and measurement setups are developed for both CTs and VTs calibration. The analysis is carried out by usin…
Current transformers effects on the measurement of harmonic active power in LV and MV networks
2011
The harmonic active power is used to determine the location of polluting loads, the direction of harmonic power flow and to estimate how consequential a certain current harmonic source is. The highest uncertainties, when measuring harmonic active power, are introduced by the current and voltage transducers. This paper presents experimental results which show the impact of current transformers (CTs) on the accuracy of the harmonic power measurements. An expression for the evaluation of the power error in distorted conditions was developed which can be easily utilized in the case of linear current transducers. It is shown how CTs cannot be considered linear transducers and how the higher the …
Intellectual Capital – The Key for Sustainable Competitive Advantage for the SME's Sector
2015
Abstract With the adoption of the Lisbon Agenda and its major objective, namely that the EU would become the most dynamic and competitive knowledge based economy in the world, it became clear the Small and Medium Enterprises (SME's) are the especially affected by these plans, because they represent the driving force for the European economy. In this context of creating and maintaining a competitive advantage for the SME's, it is crucial for them to make good use of the intellectual capital of their employees, in an efficient and proficient manner, in order to increase their potential for innovation. The aim of this article is to show, through an original argumentation, based on the analysis…
Vida más allá del PowerPoint: Un esfuerzo por superar la presente involución tecnológica de los procesos de enseñanza-aprendizaje hacia prácticas doc…
2018
La tradicional clase magistral se ha vestido o disfrazado, en el marco de la revolución digital, con tecnología para convertirse, en la pràctica, en una versión más cara y compleja, con grandes costes para los centros de enseñanza y universidades. Sigue siendo una lectura comentada por el profesor donde el alumno no tiene un papel activo, ya que es el profesor el que se considera que tiene el conocimiento, y trabaja. Los alumnos pueden preguntar si se considera necesario, ahora el estudiante no necesita ya tomar apuntes siquiera, las diapositivas de las editoriales carecen casi de erratas… Se propone con este poster dar un salto cualitativo siguiendo metodologías del mundo anglosajón para p…
On the Fast and Rigorous Analysis of Compensated Waveguide Junctions Using Off-Centered Partial-Height Metallic Posts
2007
In this paper, we present an efficient and rigorous method, based on the 3-D boundary integral-resonant-mode expansion technique, for the analysis of multiport rectangular waveguide junctions compensated with partial-height cylindrical metallic posts. The electrical performance of a great variety of commonly used wideband microwave circuits has been improved drastically thanks to the introduction of a new design parameter, i.e., the relative position of the metallic post in the structure. To the authors' knowledge, this parameter has not been taken into account in previous studies concerning compensated junctions using partial-height metallic posts. The developed tool has been successfully …