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 efficient and viable energy storage

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 g−1

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

A mechatronic design synthesis for very low flow control valves

The means by which the control of very low flows in the region of 0.1-400ml/hr using valves with microchannels (<250μm) is not well defined. This work presents a review of existing literature that contributes to the understanding of controlling very low flows. Mechatronic principles are used to bring new understanding to the field of very low flow control using needle valves. Flow rate experiments were conducted using a mechatronically controlled needle valve and a novel flow measurement device constructed for the purpose, from which an analytical flow model is developed. Details of a linear actuated needle valve are given along with open loop and closed loop control systems developed for the purpose of accurately controlling very low flows. The open loop system is derived from the valve operating principles enabling an efficient method of modelling the valve flow characteristics for the purpose of control. The closed loop method, incorporating gain scheduling is capable of controlling flows to within 0.0016ml/hr at low flows. A prototype lubricant dispensing system using a low flow needle valve was tested in an industrial environment. A design synthesis is developed by consolidating the knowledge gained from these studies is presented. This discusses the all main factors affecting the design and operation of needle valves for the control of very low flows while describing practical solutions to the problems commonly encountered

Improved prediction of shell side heat transfer in horizontal evaporative shell and tube heat exchangers

This paper presents an improved prediction method for the heat transfer and pressure drop in the shell side of a horizontal shell and tube evaporator. The results from an experimental test program are used in which a wide range of evaporating two-phase shell side flow data was collected from a TEMA E-shell evaporator. The data are compared with shell side heat transfer coefficient and pressure drop models for homogeneous and stratified flow. The comparison suggests a deterioration in the heat transfer data at low mass fluxes consistent with a transition from homogeneous to stratified flow. The pressure drop data suggest a stratified flow across the full test range. A new model is presented that suggests the transition in the heat transfer data may be due to the extent of tube wetting in the upper tube bundle. The new model, which also takes into account the orientation of the shell side baffles, provides a vast improvement on the predictions of a homogenous type model. The new model would enable designers of shell side evaporators/reboilers to avoid operating conditions where poor heat transfer could be expected, and it would also enable changes in process conditions to be assessed for their implications on likely heat transfer performance. (Abstract from WOK

Almost sure and moment exponential stability of Euler-Maruyama discretizations for hybrid stochastic differential equations

Positive results are derived concerning the long time dynamics of numerical simulations of stochastic differential equation systems with Markovian switching. Euler-Maruyama discretizations are shown to capture almost sure and momente xponential stability for all sufficiently small timesteps under appropriate conditions

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