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Abstract This paper investigates the spillovers of extreme risks between crude oil and stock markets using daily data of the S&P 500 stock index and West Texas Intermediate (WTI) crude oil futures returns. Based on the method of Granger causality in risk, Value at Risk (VaR) is employed to measure market risk, and a class of kernel-based tests is used to detect negative and positive risk spillover effects. Empirical results reveal that there are significant risk spillovers between the two markets. Extreme movements, past or current, in one market may have a significant predictive power for those in the other market. Prior to the recent financial crisis, there are positive risk spillovers from stock market to crude oil market, and negative spillovers from crude oil market to stock market. After the financial crisis, bidirectional positive risk spillovers are strengthened markedly. The risk spillovers may occur instantaneously, and/or with a (long) time delay. Both positive and negative risk spillover effects exhibit asymmetric correlations.

The large thermal potentials with geothermal gradient of abandoned wells provide the possibility and opportunity for carbon-neutrality transition of district heating systems, whereas energy harvesting from abandoned geothermal wells is full of challenges, due to the considerable initial investment in economic cost, system performance degradation, and so on. In this chapter, a systematic and comprehensive review on the application techniques of abandoned wells is presented, in terms of advanced thermal/power conversions, renewable integrations for district heating, and strategies for performance enhancement. Discussions on real applications have been conducted and future prospects presented, from perspectives of lifetime system performance, techno-economic feasibility analysis, and potential assessment of abandoned wells for carbon-neutrality transition. The results of this chapter can provide preliminary knowledge and cutting-edge technologies on renewable integrations with abandoned wells, so as to demonstrate techno-economic-environmental potentials of abandoned wells and contributions toward carbon-neutrality transition. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Design & Construction Management

Using benzo[1,2-b:4,5-b']dithiophene and two matched 5,6-difluorobenzo[2,1,3]thiadiazole-based monomers, we demonstrate that random copolymerization of two electron deficient monomers, alternating with one electron rich monomer, forms a successful approach to synthesize state-of-the-art semiconducting copolymers for organic solar cells. Over a range of compositions, these random copolymers provide impressive power conversion efficiencies (PCEs) of about 8.0%, higher than those of their binary parent polymers, and with little batch-to-batch variation. A PCE over 8% could also be achieved when the active layer was deposited from nonhalogenated solvents at room temperature.

Tip leakage vortex (TLV) in an axial flow pump was simulated by using the shear-stress transport (SST) k-ω turbulence model with a refined high-quality structured grid at different flow rate conditions. The TLV trajectories were obtained by using the swirling strength method corresponding to the cross-sections of streamlines of the TLV. High-speed photography experiments were conducted to observe the TLV trajectory based on cavitation tracing bubbles in an axial flow pump with a transparent casing. The TLV trajectories predicted by the SST k-ω turbulence model agreed well with the visualization results. The numerical and experimental results show that the starting point of the TLV is near the leading edge at part-load flow rate condition (Q/QBEP=0.85), and it moves towards the trailing edge to approximately 20% blade chord at the design flow rate condition (Q/QBEP=1.0). At large flow rate conditions (Q/QBEP=1.2), the starting point of the TLV shifts to about 40% blade chord, and the relative angle between the TLV trajectory and the blade chord is gradually reduced with the increased flow rate. Detailed statistics of the fluid dynamics of the end-wall shear layer and the TLV at design and off-design conditions were discussed based on the numerical results. The shear layer and jetting flow in the tip gap are highly affected by the pressure difference between the pressure side (PS) and suction side (SS). It was also found that the distributions of static pressure, turbulent kinetic energy (TKE) and vorticity inside the TLV core are associated with the TLV structure which is affected by blade loading and operation conditions of the axial flow pump.

I bring out the limitations of four important views of what the target of useful climate model assessment is. Three of these views are drawn from philosophy. They include the views of Elisabeth Lloyd and Wendy Parker, and an application of Bayesian confirmation theory. The fourth view I criticise is based on the actual practice of climate model assessment. In bringing out the limitations of these four views, I argue that an approach to climate model assessment that neither demands too much of such assessment nor threatens to be unreliable will, in typical cases, have to aim at something other than the confirmation of claims about how the climate system actually is. This means, I suggest, that the Intergovernmental Panel on Climate Change’s (IPCC¿s) focus on establishing confidence in climate model explanations and predictions is misguided. So too, it means that standard epistemologies of science with pretensions to generality, e.g., Bayesian epistemologies, fail to illuminate the assessment of climate models. I go on to outline a view that neither demands too much nor threatens to be unreliable, a view according to which useful climate model assessment typically aims to show that certain climatic scenarios are real possibilities and, when the scenarios are determined to be real possibilities, partially to determine how remote they are.

The use of natural gas as fuel for solid oxide fuel cell is one of main potentials of this technology to be exploited as an efficient and profitable future power generation source. However, using direct methane (main component of natural gas) in conventional nickel-based fuel cells leads to carbon deposition problem which causes performance failure even in short period (24 h). According to thermodynamic principles, fuel addition with oxygen carriers is a good solution to prevent carbon deposition problem. Among the different options, a deep investigation is here presented for the air addition case. Through experimental activity under different operating conditions and suitable performance and structural cell characterization, the 1:5 optimal air addition to methane is determined, providing outcomes of interest for SOFC operation optimization in case of direct methane feeding. In fact, through impedance spectroscopy analysis and voltage measurements, as well as ex-post structural analysis, it is proved that in these conditions both carbon deposition and anode layers delamination are avoided, also after 100 h operation; moreover a cell stable operation at 0.6 V is guaranteed. The proposed operation mode, therefore, represents a promising solution, to be deeply investigated in the future at stack level, for SOFCs directly fed with natural gas.

This special issue is a result of work of Sustainable Consumption Research Exchanges (SCORE!). This EU supported network project under the 6th Framework Program engaged a few hundred professionals interested in sustainable consumption and production (SCP) in Europe and beyond. A key goal of the network is to enhance understanding how radical reductions of environmental impacts and at global level a more equitable growth can be realised. In April 2006, SCORE! organised a workshop in Copenhagen with support of the European Environment Agency, titled 'Governance of change to Sustainable Consumption and Production'. This special issue contains 7 papers based on presentations during that workshop. It further contains a summary of the main conclusions drawn by the SCORE! project team on the basis of a broader review of radical change to SCP from a business, design, consumer and system innovation perspective. The conclusion is unambiguously that governments cannot 'outsource politics', but must form a 'triangle of change' with business and consumers. We have further to understand the systemic nature of the change required. Some policies are currently more viable than others, given existing mega-trends, mega-structures and mega-views, which cannot be changed easily in the short-term and usually cannot be tackled head-on. Such issues, like paradigms on the possibility of continuous exponential growth, the belief in free markets and trade, need a longer-term deliberative process before change is possible. © 2007 Elsevier Ltd. All rights reserved.

Wing-diesel engine-powered hybrid ships can effectively reduce fuel consumption and CO2 emissions by using wind energy as the auxiliary driving power. The energy optimization management of the hybrid system can further improve the ship's energy efficiency. To achieve this purpose, it is significant to establish an effective energy consumption model for the energy optimization management of the hybrid system. Therefore, an energy consumption model is established based on the energy conversion analysis of the hybrid power system in this paper. This model can effectively describe the energy consumption of the hybrid ship under different navigational environmental conditions. Then, a joint optimization method of the wing attack angle and of the sailing speed for the hybrid ship is proposed by adopting a swarm intelligence optimization algorithm, in order to reduce energy consumption and CO2 emissions of the hybrid ship under different navigational environmental conditions. Finally, the energy consumption optimization potentials by adopting the hybrid power system and the proposed joint optimization method are analyzed. The results show that the energy consumption and CO2 emissions along a typical route can be reduced by about 4.5%. This study provides an important basis for future practical operations of wing-diesel engine-powered hybrid ships. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Transport Engineering and Logistics