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An aerodynamic shape optimization method for a horizontal axis wind turbine is developed and verified through experimentation with a laboratory-scale wind turbine. Our method is based on matching the rotor's and the coupled generator's torque. Prior to shape optimization, an initial rotor design is established with a hybrid use of Schmitz and blade element momentum theories. The experimental verification of the developed method is conducted with a small-scale wind turbine; thus, the operating Reynolds number is one order of magnitude lower than large-scale wind turbines. Therefore, a high-lift low-Re airfoil, namely, SG6043, is selected for the blade along the whole span. The shape is optimized by determining the optimum chord and cumulative pitch angle distributions by manipulating the tapering and twisting of the blade. The objective of the optimization is to maximize the turbine's power coefficient Cp, while maintaining the torque equal to that of the generator. The generator's characteristics are found through experimentations which are conducted apart from the wind tunnel experiments. During the optimization process, the local aerodynamic forces on the blade are calculated by interfacing the optimization program with XFOIL; thus, the torque and power can be calculated for the rotor at each iteration step. The optimized turbine performance is evaluated under a design and off-design operating condition. The performance verification experiments are carried out in the wind tunnel with a specially designed setup. A comparison of the measured and computed performance shows good agreement.

This paper presents a new approach to assess and improve the environmental and economic performance of integrated electricity and heat district energy systems in light of (i) optimal operation of available multi-energy components (e.g., cogeneration and heat pumps) and (ii) energy exchanges within the district through internal electricity and heat networks. The latter is particularly attractive as, instead of constraining energy flows within each building, it enables the production and consumption of energy in the most attractive locations (e.g., in buildings that can accommodate photovoltaic panels). The proposed methodology is formulated as a mixed integer linear programming problem, and demonstrated with a real UK district comprising internal electricity and heat networks and several buildings. The results highlight the attractiveness of optimising multiple energy vectors, particularly in light of energy exchanges between buildings, in economic and environmental terms.

Abstract This study presents an evaluation of the error induced by neglecting the effect of air compressibility in modelling Oscillating Water Column (OWC) wave energy converters. A compressible two phases CFD model in the open-source software package OpenFOAM® is validated and then used to simulate a fixed OWC device, detached from the sea bottom. A comparative analysis of the results obtained by simulating the device at full-scale (1:1) and at four smaller scales (1:50, 1:25, 1:10 and 1:5) is performed in order to assess the scale effects associated with air compressibility. Indeed, for the air pressure levels considered in the simulations (up to 350 Pa at model scale 1:50), the effect of neglecting the air compressibility results in an overestimation up to about 15% for the air pressure in the OWC chamber and the subsequent air volume flux, but less than 10% for the capture width ratio. This overestimation increases with increasing pressure level. Results are analysed in terms of dimensionless parameters and a new parameter, strongly related to the compressible effects, is proposed and used to provide generalized equations delivering correction factors.

The potential of renewable energy should be fully exploited in the transportation sector to achieve a cleaner production. Therefore, this paper proposes an on-grid hybrid hydrogen refueling and battery swapping station powered by wind energy. This novel concept can promote the development of low-carbon emission vehicles including hydrogen-based vehicle and battery electric vehicle. During the daily operation of the station, the multiple uncertainties may lead to a higher operational cost. To address this problem, a hybrid stochastic/distributionally robust optimization method is proposed to handle different uncertainties for the energy management problem. The first type of uncertainties can be depicted by a certain distribution, i.e. electricity price and wind power, which is processed by a stochastic optimization method. The second type of uncertainties is associated with human behaviors and is difficult to find its probability distribution, i.e. the hydrogen demand of hydrogen-based vehicles, so the second type is processed by a distributionally robust optimization method. The overall objective is to minimize the total operational cost of the station, which also considers the battery swapping station overstock punishment. Because a reasonable battery swapping scheduling can reduce the waiting time of users and operational cost of the station. The results indicate that the proposed method can effectively address the conservatism of solutions as its total operational cost is 4.4% lower than that of the hybrid stochastic/robust optimization method under a high confidence level.

It is widely known that fossil fuels are limited; consequently, the generation of new sources of energy in a clean and environmentally friendly manner is a research priority. Bioethanol appears to be one potential solution, especially second-generation production from renewable biomass.In order to use lignocellulosic feedstock to produce bioethanol, its polysaccharide components, cellulose and hemicellulose, must be hydrolysed into soluble sugars, which can then be converted into ethanol by fermentative microorganisms such as Geobacillus thermoglucosidasius TM242 used by the company ReBio Technologies Ltd.To date, the cost of commercial enzymes used during the hydrolysis process remains a major economic consideration in the production of second-generation bioethanol as an alternative fuel. The research project presented in this thesis aims to improve this rate-limiting step of microbial bioethanol production through an investigation of the different enzymes associated with hemicellulose hydrolysis. Firstly, the TM242 genome sequence revealed a number of genes encoding glycoside-hydrolases. Six of these genes were cloned and expressed in E. coli and the recombinant enzymes characterised; three of them, two β-xylosidases and an α arabinofuranosidase, are relevant to xylan hydrolysis, and were found to be highly active and thermostable. Crystallisation of one of the β-xylosidases permitted the determination of a high-resolution (1.7 Å) structure of the apo-enzyme along with a lower resolution (2.6 Å) structure of the enzyme-substrate complex, resulting in the first reported structure of a GH52 family member (Espina et al., 2014).Secondly, as the TM242 microorganism lacks xylanase enzymes, four genes encoding xylanases from closely-related Geobacillus strains were cloned and expressed in E. coli, with one of them being also successfully cloned and expressed in G. thermoglucosidasius TM242. This heterologous xylanase was secreted in active form representing an enhanced biomass utilisation by TM242.In conclusion, it is felt that the findings presented here have the potential to make a valuable contribution towards second-generation bioethanol production.

Antiprotons have been suggested as a possibly superior modality for radiotherapy, due to the energy released when antiprotons annihilate, which enhances the Bragg peak and introduces a high-LET component to the dose. However, concerns are expressed about the inferior lateral dose distribution caused by the annihilation products.We use the Monte Carlo code FLUKA to generate depth-dose kernels for protons, antiprotons, and carbon ions. Using these we then build virtual treatment plans optimized according to ICRU recommendations for the different beam modalities, which then are recalculated with FLUKA. Dose-volume histograms generated from these plans can be used to compare the different irradiations.The enhancement in physical and possibly biological dose from annihilating antiprotons can significantly lower the dose in the entrance channel; but only at the expense of a diffuse low dose background from long-range secondary particles. Lateral dose distributions are improved using active beam delivery methods, instead of flat fields.Dose-volume histograms for different treatment scenarios show that antiprotons have the potential to reduce the volume of normal tissue receiving medium to high dose, however, in the low dose region antiprotons are inferior to both protons and carbon ions. This limits the potential usage to situations where dose to normal tissue must be reduced as much as possible.

This report has been commissioned by Friends of the Earth England Wales and Northern Ireland (FoE) to independently review evidence on key issues relating to the potential new fleet of nuclear power stations that may be built in the UK over the period 2017 to 2030. The report draws primarily on peer-reviewed academic literature although this is supplemented with “grey” literature from credible government, consultancy and policy sources. It is not an exhaustive review of all the issues and writing concerning civil nuclear power but has a specific scope outlined below (see Annex 1 for full Terms of Reference). Nuclear power is quite unlike both fossil fuels and renewable sources of electricity generation with a particular set of characteristics that may be beneficial or problematic. The main purpose of this report is to provide a succinct appraisal of key issues relevant to the plans for a new generation of reactors in the UK, namely:• safety• radioactive waste disposal• proliferation of nuclear weapons• economics of nuclear power• siting and planning of low carbon generation• employment • issues in managing a low carbon grid• interactions between nuclear power and other low carbon technologiesThese issues are presented in separate sections as reviews of existing primary research and not as new research findings. The penultimate section, Chapter 11, presents new work by Tyndall Manchester on the carbon dioxide emissions implications of using gas rather than building a new series of nuclear power stations. We calculate the emissions output if the shortfall in electricity generation were to be met by the use of combined cycle gas turbines (CCGT). Alternative renewable energy sources are not considered as their direct emissions are negligible and similar to those from nuclear stations. A range of scenarios is presented for different combinations of rates and extent of nuclear construction and the availability and performance of carbon capture and storage technology. This report is intended for detailed consideration by the staff and members of Friends of the Earth and does not include an executive summary. Direct recommendations as to the appropriateness of a new fleet of nuclear stations in the UK have not been made by the authors. It is also important to note that some key aspects are highly contextual and contingent upon future circumstance.

China joined the ICOM in 1983. Joining such an international community of museological experts and scholars implied sharing the standards and founding principles, however if we consider the development and the status quo of the art museum system in China, it is possible to point out some contradictions and peculiarities. Since the early 1980s, following a renovation process of the entirety of Chinese national institutions, the museum system has been enjoying an unprecedented development. As well, a more general discourse on the cultural heritage of the country has increasingly gained a prominent position in the cultural policy agenda. As far as art museums are concerned, since the end of the 1990s, the country has been experiencing a rapid and unprecedented development as well, encompassing both the state-owned and private sector. However, today the proliferation of art museums appears to be more driven by the compulsion for a status symbol rather than pursuing a cultural mission. Therefore, a key question arises concerning the quality of these art institutions, their effective role in the promotion of art, and their cultural impact. This study aims to enrich the debate on museums of contemporary art, and intends to offer a parameter of sustainability in order to evaluate the Chinese art museum system.