359 research outputs found
Energy storage : the route to liberation from the fossil fuel economy?
If a low-carbon energy strategy is to be developed up to 2050, renewable energy sources will need to be deployed on a large scale against a scenario of increasing global energy demand. Renewables will vary from large-scale regional wind and marine clusters to more localised 'micro' generation. If a low-carbon strategy is to be successful, automotive transport will also need to be linked to the renewable infrastructure. Both of these need the development of efļ¬cient and viable energy storage
Improving the PhD through provision of skills training for postgraduate researchers
Postgraduate research degrees in some systems, such as the UK, can be almost exclusively research based, with little formal, compulsory taught component. Government reviews recommend 10 days per year training in generic or transferable skills to ensure the suitability of doctoral graduates for employment. Professional bodies stipulate a commitment to continuing professional development as a requirement for chartered or accredited status. This includes The Chartered Society of Forensic Science and the British Association for Forensic Anthropology, as well as institutions for related fields such as The Institution of Engineering and Technology. Increasing numbers of universities therefore offer skills training programmes. Research students were surveyed to investigate their attendance and views on non-mandatory training courses, and only 33% of students agreed that all training needs were covered by their degree. However, in contrast to the recommended training commitment, over a one-year period students attended a mean of 5.5Ā±0.7 training days, with 12% attending no training. Responses indicate a significant demand for increased training in management, consistent with government reviews; however, this work also indicates that provision of technical training should be addressed.Short course availability, design, delivery, promotion and recognition are discussed in relation to improving student uptake to reduce to the discrepancy between attendance levels and recommendations or aspirations
Energy-storage technologies and electricity generation
As the contribution of electricity generated from renewable sources (wind, wave, solar) grows, the inherent intermittency of supply from such generating technologies must be addressed by a step-change in energy storage. Furthermore, the continuously developing demands of contemporary applications require the design of versatile energy-storage/power-supply systems offering wide ranges of power density and energy density. As no single energy-storage technology has this capability, systems will comprise of combinations of technologies such as electrochemical supercapacitors, flow batteries, Lithium-ion batteries, superconducting magnetic energy storage (SMES) and kinetic energy storage. The evolution of the electrochemical supercapacitor is largely dependent on the development of optimised electrode materials (tailored to the chosen electrolyte) and electrolytes. Similarly, the development of Lithium-ion battery technology requires fundamental research in materials science aimed at delivering new electrodes and electrolytes; Lithium-ion technology has significant potential and a step-change is required in order to promote the technology from the portable electronics market into high-duty applications. Flow-battery development is largely concerned with safety and operability. However, opportunities exist to improve electrode technology yielding larger power densities. The main barriers to overcome in terms of the development of SMES technology are those related to high-temperature superconductors in terms of their granular, anisotropic nature. Materials development is essential for the successful evolution of flywheel technology. Given the appropriate research effort, the key scientific advances required in order to successfully develop energy-storage technologies generally represent realistic goals which may be achieved by 2050
Towards task-based personal information management evaluations
Personal Information Management (PIM) is a rapidly growing area of research concerned with how people store, manage and re-find information. A feature of PIM research is that many systems have been designed to assist users manage and re-find information, but very few have been evaluated.This has been noted by several scholars and explained by the difficulties involved in performing PIM evaluations.The difficulties include that people re-find information from within unique personal collections; researchers know little about the tasks that cause people to re-find information; and numerous privacy issues concerning personal information. In this paper we aim to facilitate PIM evaluations by addressing each of these difficulties. In the first part, we present a diary study of information re-finding tasks. The study examines the kind of tasks that require users to re-find information and produces a taxonomy of re-finding tasks for email messages and web pages. In the second part, we propose a task-based evaluation methodology based on our findings and examine the feasibility of the approach using two different methods of task creation
Preparation of controlled porosity carbon aerogels for energy storage in rechargeable lithium oxygen batteries
Porous carbon aerogels are prepared by polycondensation of resorcinol and formaldehyde catalyzed by sodium carbonate followed by carbonization of the resultant aerogels in an inert atmosphere. Pore structure of carbon aerogels is adjusted by changing the molar ratio of resorcinol to catalyst during gel preparation and also pyrolysis under Ar and activation under CO2 atmosphere at different temperatures. The prepared carbons are used as active materials in fabrication of composite carbon electrodes. The electrochemical performance of the electrodes has been tested in a Li/O2 cell. Through the galvanostatic charge/discharge measurements, it is found that the cell performance (i.e. discharge capacity and discharge voltage) depends on the morphology of carbon and a combined effect of pore volume, pore size and surface area of carbon affects the storage capacity. A Li/O2 cell using the carbon with the largest pore volume (2.195 cm3/g) and a wide pore size (14.23 nm) showed a specific capacity of 1290 mA h gā1
Sodium-mediated magnesiation of thiophene and tetrahydrothiophene : structural contrasts with furan and tetrahydrofuran
Sulfur-containing heterocycles are currently attracting agreat deal of interest in several diverse fields. For instance, substituted tetrahydrothiophenes have received considerable attention due to their extremely wide-ranging chemical and biological applications.These include their use as potent a-glucosidase inhibitors, as an inhibitor of copper amine oxidases and as selective A3 agonists and antagonists. In addition, they have been utilised in chemical transformations, such as catalytic asymmetric epoxidation, catalytic intramolecular cyclopropanation, and asymmetric metal catalysis hydrogenation. From a nanochemical perspective,the adsorption chemistries and physical propertiesof various thiophenes and tetrahydrothiophenes on gold surfaces have recently come to the fore.[7] Polythiophenes are also key compounds in modern materials research, currently utilised in, for example, the fabrication of semi-conducting, fluorescent, and electronic and optoelectronic materials.[8]In this work, metallation (exchange of a hydrogen atom with a metal atom) of the parent heterocycles, tetrahydrothiophene (THT) and thiophene is considered. Metallation is one of the most fundamental reactions in modern day synthesis and is a key tool in the preparation of functionalised aromaticand heterocyclic compounds. It is usually achieved bythe utilisation of commercially accessible organolithiums (or lithium amides); however, these reactions do have theirdrawbacks, including the intolerance of certain functionalgroups, the need for cryoscopic temperatures and the inadvertent reactivity with polar reaction solvents
Categorisation of designs according to preference values for shape rules
Shape grammars have been used to explore design spaces through design generation according to sets of shape rules with a recursive process. Although design space exploration is a persistent issue in computational design research, there have been few studies regarding the provision of more preferable and refined outcomes to designers. This paper presents an approach for the categorisation of design outcomes from shape grammar systems to support individual preferences via two customised viewpoints: (i) absolute preference values of shape rules and (ii) relative preference values of shape rules with shape rule classification levels with illustrative examples
Synthesis of indoles via alkylidenation of acyl hydrazides
Indoles have been synthesised via alkylidenation of acyl phenylhydrazides using phosphoranes and the Petasis reagent, followed by in situ thermal rearrangement of the product enehydrazines. The Petasis reagent provides an essentially neutral equivalent of the [acid-catalysed] Fischer indole synthesis, but with acyl phenylhydrazides as starting substrates. Alkylidene triphenylphosphoranes convert aroyl phenylhydrazides to indoles, but acyl phenylhydrazides derived from aliphatic carboxylic acids undergo a Brunner reaction to form indolin-2-ones
State-space approach to nonlinear predictive generalized minimum variance control
A Nonlinear Predictive Generalized Minimum Variance (NPGMV) control algorithm is introduced for the control of nonlinear discrete-time multivariable systems. The plant model is represented by the combination of a very general nonlinear operator and also a linear subsystem which can be open-loop unstable and is represented in state-space model form. The multi-step predictive control cost index to be minimised involves both weighted error and control signal costing terms. The solution for the control law is derived in the time-domain using a general operator representation of the process. The controller includes an internal model of the nonlinear process but because of the assumed structure of the system the state observer is only required to be linear. In the asymptotic case, where the plant is linear, the controller reduces to a state-space version of the well known GPC controller
A novel approach to structural load control using intelligent actuators
The recent trend towards large multi-MW wind turbines resulted in the role of the control system becoming increasingly important. The extension of the role of the controller to alleviate structural loads has motivated the exploration of novel control strategies, which seek to maximise load reduction by exploiting the blade pitch system. The reduction of blade fatigue loads through individual blade pitch control is one of the examples. A novel approach to reduction of the unbalanced rotor loads by pitch control is presented in this paper. Each blade is equipped with its own actuator,sensors and controller. These local blade control loops operate in isolation without a need of communication with each other. The single blade control approach to regulation of unbalanced rotor loads presented in this paper has an important advantage of being relatively easy to design and tune. Furthermore, it does not affect the operation of the central controller and the latter need not be re-designed when used in conjunction with the single blade controllers. Their performance is assessed using BLADED simulations
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