208 resultados para Fuel trade
Resumo:
Providing the first comprehensive examination of the key regulatory disciplines included in the new generation of EU free trade agreements (FTAs), this book investigates the EU's supposed deep trade agenda through a legal analysis of these FTAs. In doing so, Billy A. Melo Araujo determines whether there is any substance behind the EU's foreign policy rhetoric regarding the need to introduce regulatory issues within the remit of international trade law.
At a time when the EU is busily negotiating so-called 'mega-FTAs', such as the Transatlantic Trade and Investment Partnership (TTIP) and the plurilateral Trade in Services Agreement (TISA), Melo Araujo offers a timely insight into the important questions raised by such FTAs, in particular concerning the future of the multilateral trade system, the loss of policy autonomy, and the democratic legitimacy of regulating through treaty-making. The book provides a detailed analysis of the regulatory disciplines included in the more recent EU FTAs and explores the possible implications of such disciplines. Offering a significant contribution to a wider debate, this is a must read for those interested in the legal dimension of the EU's deep trade agenda.
Resumo:
The issue of concession bargaining between employers and unions during the Great Recession has received little attention in the research literature. This article presents a systematic analysis of the conduct of concession bargaining during the recession in Ireland in the context of three forms of concession bargaining identified in the international literature: integrative concession bargaining, distributive concession bargaining and ultra concession bargaining – each with different but overlapping sets of institutional foundations and implications for employers and trade unions. Drawing on focus groups of managers and union officials and a representative survey of employers, the article shows that distributive concession bargaining has been the predominant form in the Irish recession. This form of concession bargaining is likely to have few lasting direct effects on employer or union roles in collective bargaining but nevertheless appears to have significant indirect implications for the silent marginalization of unions in workplaces.
Resumo:
Mathematical models are useful tools for simulation, evaluation, optimal operation and control of solar cells and proton exchange membrane fuel cells (PEMFCs). To identify the model parameters of these two type of cells efficiently, a biogeography-based optimization algorithm with mutation strategies (BBO-M) is proposed. The BBO-M uses the structure of biogeography-based optimization algorithm (BBO), and both the mutation motivated from the differential evolution (DE) algorithm and the chaos theory are incorporated into the BBO structure for improving the global searching capability of the algorithm. Numerical experiments have been conducted on ten benchmark functions with 50 dimensions, and the results show that BBO-M can produce solutions of high quality and has fast convergence rate. Then, the proposed BBO-M is applied to the model parameter estimation of the two type of cells. The experimental results clearly demonstrate the power of the proposed BBO-M in estimating model parameters of both solar and fuel cells.
Resumo:
Clean and renewable energy generation and supply has drawn much attention worldwide in recent years, the proton exchange membrane (PEM) fuel cells and solar cells are among the most popular technologies. Accurately modeling the PEM fuel cells as well as solar cells is critical in their applications, and this involves the identification and optimization of model parameters. This is however challenging due to the highly nonlinear and complex nature of the models. In particular for PEM fuel cells, the model has to be optimized under different operation conditions, thus making the solution space extremely complex. In this paper, an improved and simplified teaching-learning based optimization algorithm (STLBO) is proposed to identify and optimize parameters for these two types of cell models. This is achieved by introducing an elite strategy to improve the quality of population and a local search is employed to further enhance the performance of the global best solution. To improve the diversity of the local search a chaotic map is also introduced. Compared with the basic TLBO, the structure of the proposed algorithm is much simplified and the searching ability is significantly enhanced. The performance of the proposed STLBO is firstly tested and verified on two low dimension decomposable problems and twelve large scale benchmark functions, then on the parameter identification of PEM fuel cell as well as solar cell models. Intensive experimental simulations show that the proposed STLBO exhibits excellent performance in terms of the accuracy and speed, in comparison with those reported in the literature.
Resumo:
The ability to directly utilize hydrocarbons and other renewable liquid fuels is one of the most important issues affecting the large scale deployment of solid oxide fuel cells (SOFCs). Herein we designed La0.2Sr0.7TiO3-Ni/YSZ functional gradient anode (FGA) supported SOFCs, prepared with a co-tape casting method and sintered using the field assisted sintering technique (FAST). Through SEM observations, it was confirmed that the FGA structure was achieved and well maintained after the FAST process. Distortion and delamination which usually results after conventional sintering was successfully avoided. The La0.2Sr0.7TiO3-Ni/YSZ FGA supported SOFCs showed a maximum power density of 600mWcm-2 at 750°C, and was stable for 70h in CH4. No carbon deposition was detected using Raman spectroscopy. These results confirm the potential coke resistance of La0.2Sr0.7TiO3-Ni/YSZ FGA supported SOFCs.
Resumo:
A novel electrical current applied technique known as flash sintering has been applied to rapidly (within 10 min) densify electrolytes including Ce0.8Gd0.2O1.9 (GDC20), Ce0.9Gd0.1O1.95 (GDC10), and Ce0.8Sm0.2O1.9 (SDC20) for application in Solid Oxide Fuel Cells (SOFCs). The densification temperature for the three electrolytes was 554°C, 635°C, and 667°C, respectively, which is far below conventional sintering temperatures. All specimens after flash sintering maintained the pure fluorite structure and exhibited a well-densified microstructure. To investigate the flash-sintering mechanism, we have applied Joule heating effect with blackbody radiation theory, and found that this theory could reasonably interpret the flash-sintering phenomenon by matching theoretically calculated temperature with the real temperature. More importantly, one of the materials inherent properties, the electronic conductivity, has been found correlated with the onset of flash sintering, which indicates that the electrons and holes are the primary current carriers during the start of flash-sintering process. As a result, potential densification mechanisms have been discussed in terms of spark plasma discharge.
Resumo:
In this paper, niobium doping is evaluated as a means of enhancing the electrochemical performance of a Sr2Fe1.5Mo0.5O6-δ (SFM) perovskite structure cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) applications. As the radius of Nb approximates that of Mo and exhibits +4/+5 mixed valences, its substitution is expected to improve material performance. A series of Sr2Fe1.5Mo0.5-xNbxO6-δ (x = 0.05, 0.10, 0.15, 0.20) cathode materials are prepared and the phase structure, chemical compatibility, microstructure, electrical conductivity, polarization resistance and power generation are systematically characterized. Among the series of samples, Sr2Fe1.5Mo0.4Nb0.10O6-δ (SFMNb0.10) exhibits the highest conductivity value of 30 S cm-1 at 550°C, and the lowest area specific resistance of 0.068 Ω cm2 at 800°C. Furthermore, an anode-supported single cell incorporating a SFMNb0.10 cathode presents a maximum power density of 1102 mW cm-2 at 800°C. Furthermore no obvious performance degradation is observed over 15 h at 750°C with wet H2(3% H2O) as fuel and ambient air as the oxidant. These results demonstrate that SFMNb shows great promise as a novel cathode material for IT-SOFCs.
Resumo:
Ageing workforces are placing conflicting pressures on European trade unions in order to, on the one hand, protect pensions and early retirement routes, and, on the other, promote human resource management (HRM) policies geared towards enabling their older members to extend working life. Using interviews from German and United Kingdom (UK) trade unions, we discuss how unions are both constrained and enabled by pre-existing institutional structures in advocating approaches to age management. In Germany, some unions use their strong institutional role to affect public policy and industrial change at national and sectoral levels. UK unions have taken a more defensive approach, focused on protecting pension rights. The contrasting varieties of capitalism, welfare systems and trade unions’ own orientations are creating different pressures and
mechanisms to which unions need to respond. While the German inclusive system is providing unions with mechanisms for negotiating collectively at the national level, UK unions’ activism remains localized.
Resumo:
In exploration of low-cost electrocatalysts for direct methanol fuel cells (DMFCs), Pt modified tungsten carbide (WC) materials are found to be great potential candidates for decreasing Pt usage whilst exhibiting satisfactory reactivity. In this work, the mechanisms, onset potentials and activity for electrooxidation of methanol were studied on a series of Pt-modified WC catalysts where the bare W-terminated WC(0001) substrate was employed. In the surface energy calculations of a series of Pt-modified WC models, we found that the feasible structures are mono- and bi-layer Pt-modified WCs. The tri-layer Pt-modified WC model is not thermodynamically stable where the top layer Pt atoms tend to accumulate and form particles or clusters rather than being dispersed as a layer. We further calculated the mechanisms of methanol oxidation on the feasible models via methanol dehydrogenation to CO involving C-H and O-H bonds dissociating subsequently, and further CO oxidation with the C-O bond association. The onset potentials for the oxidation reactions over the Pt-modified WC catalysts were determined thermodynamically by water dissociation to surface OH* species. The activities of these Pt-modified WC catalysts were estimated from the calculated kinetic data. It has been found that the bi-layer Pt-modified WC catalysts may provide a good reactivity and an onset oxidation potential comparable to pure Pt and serve as promising electrocatalysts for DMFCs with a significant decrease in Pt usage.
Resumo:
Alkali activated binders, based on ash and slag, also known as geopolymers, can play a key role in reducing the carbon footprint of the construction sector by replacing ordinary Portland cement in some concretes. Since 1970s, research effort has been ongoing in many research institutions. In this study, pulverized fuel ash (pfa) from a UK power plant, ground granulated blast furnace slag (ggbs) and combinations of the two have been investigated as geopolymer binders for concrete applications. Activators used were sodium hydroxide and sodium silicate solutions. Mortars with sand/binder ratio of 2.75 with several pfa and ggbs combinations have been mixed and tested. The optimization of alkali dosage (defined as the Na2O/binder mass ratio) and modulus (defined as the Na2O/SiO2 mass ratio) resulted in strengths in excess of 70 MPa for tested mortars. Setting time and workability have been considered for the identification of the best combination of pfa/ggbs and alkali activator dosage for different precast concrete products. Geopolymer concrete building blocks have been replicated in laboratory and a real scale factory trial has been successfully carried out. Ongoing microstructural characterization is aiming to identify reaction products arising from pfa/ggbs combinations.
Resumo:
A preliminary investigation of electrocatalytic oxidation activity ofbutanol isomers has been carried out to study their potential asfuels for direct alcohol fuel cells. The electrochemical study wascarried out on Pt and Pd electrodes using a three electrode cell setup in alkaline media. The primary alcohol isomers of butanol wereobserved to behave similarly in their electrochemical reactionswhereas 2-butanol showed completely different oxidation featureson both catalysts. For example, no poisoning effects were observedfor 2- butanol unlike for the primary butanol isomers. In contrast,tert-butanol did not show any oxidation reaction on Pt and Pdelectrodes. Furthermore, Pd was not active at all in acidic mediafor butanol oxidation. The reactivity of butanol isomers were foundto be in the order n-butanol>iso-butanol>2-butanol>tert-butanolbased on the oxidation current density values.