Design and development of a low NOx Coanda ejector burner

Small gaseous combustion systems are being targeted by strict pollution legislation which will provide challenges to reduce the NOx being emitted. A novel type of gas burner has been successfully designed and developed which incorporates a Coanda ejector to promote recirculation of flue gas from the burner exit. This provides a combustion system which gives very low emissions of NOx and CO, whilst maintaining a high degree of flame stability over a range of air/fuel ratios and fuel flow rates. Recirculation of flue gas was obtained by manipulating the aerodynamics of the system, without the aid of external duct work or moving parts. The design of the burner allowed very low pollutant emissions near stoichiometric conditions, resulting in high temperatures of the exit gas. Potential applications of this type of burner are in small and intermediate furnaces where low NOx emissions are required. Moreover, very high-temperature applications, such as glass furnaces could benefit in both cost and pollutant emissions from such a burner.

Rational expectations? Developer behaviour and development cycles in the central London office market

Purpose – Expectations of future market conditions are acknowledged to be crucial for the development decision and hence for shaping the built environment. The purpose of this paper is to study the central London office market from 1987 to 2009 and test for evidence of rational, adaptive and naive expectations. Design/methodology/approach – Two parallel approaches are applied to test for either rational or adaptive/naive expectations: vector auto-regressive (VAR) approach with Granger causality tests and recursive OLS regression with one-step forecasts. Findings – Applying VAR models and a recursive OLS regression with one-step forecasts, the authors do not find evidence of adaptive and naïve expectations of developers. Although the magnitude of the errors and the length of time lags between market signal and construction starts vary over time and development cycles, the results confirm that developer decisions are explained, to a large extent, by contemporaneous and historic conditions in both the City and the West End, but this is more likely to stem from the lengthy design, financing and planning permission processes rather than adaptive or naive expectations. Research limitations/implications – More generally, the results of this study suggest that real estate cycles are largely generated endogenously rather than being the result of large demand shocks and/or irrational behaviour. Practical implications – Developers may be able to generate excess profits by exploiting market inefficiencies but this may be hindered in practice by the long periods necessary for planning and construction of the asset. Originality/value – This paper focuses the scholarly debate of real estate cycles on the role of expectations. It is also one of very few spatially disaggregate studies of the subject matter.

New rôles and development rules for housing associations: rhe rise of design and build?

This paper summarises an initial report carried out by the Housing Business Research Group, of the University of Reading into Design and Build procurement and a number of research projects undertaken by the national federation of Housing Associations (NFHA), into their members' development programmes. The paper collates existing statistics from these sources and examines the way in which Design and Build procurement can be adapted for the provision of social housing. The paper comments on these changes and questions how risk averting the adopted strategies are in relation to long term housing business management issues arising from the quality of the product produced by the new system.

Sustainable land management and development: the role of the chartered surveyor

Despite the growing intensity of the debate about environmental management, it is only recently that rural practice surveyors have become aware of its significance and potential. Consequently, few surveyors are yet in a position to offer professional advice, despite evidence from the RICS's client needs survey that nearly half of all existing clients require more advice on environmental matters. As a prerequisite to becoming involved in environmental management, it is clear that chartered surveyors have to develop new skills alongside new perceptions of their work. Rather than being conterminous, however, the alignment of these attributes reflects a fundamental tension. This is focused on the dichotomy between the strategic construction of the environment as a basis for realigning corporate policy and the more limited evocation of environmentalism as potential new business. This paper seeks to explore the nature and policy context of sustainable development, in the process examining its significance for rural chartered surveyors. In doing so, the paper will seek to contrast the essentially anthropocentric utilitarianism of surveyors' current attitudes with the radical agenda inferred by a more ecocentric, sustainable development approach to professional management and advice. The paper will conclude with a discussion about how far the principles of sustainable development can be incorporated into the management of surveying businesses, and what this implies for the future of the rural practice chartered surveyor as land manager.

Language capital and development: the case of African language publishing for children in South Africa

In recognizing 11 official languages, the 1996 South African Constitution provides a context for the management of diversity with important implications for the redistribution of wealth and power. The development and implementation of the language-in-education policies which might be expected to flow from the Constitution, however, have been slow and ineffective. One of the casualties of government procrastination has been African language publishing. In the absence of well-resourced bilingual education, most learners continue to be taught through the medium of English as a second language. Teachers are reluctant to use more innovative pedagogies without the support of adequate African language materials and publishers are cautious about producing such materials. Nonetheless, activity in this sector offers many opportunities for African language speakers. This paper explores the challenges and constraints for African language publishing for children and argues that market forces and language policy need to work in mutually reinforcing ways. Further progress is necessarily dependent on the political will to implement language-in-education policies that promote additive bilingualism and, in the process, guarantee sales for risk-averse publishers.

Ice formation and development in aged, wintertime cumulus over the UK: observations and modelling

In situ high resolution aircraft measurements of cloud microphysical properties were made in coordination with ground based remote sensing observations of a line of small cumulus clouds, using Radar and Lidar, as part of the Aerosol Properties, PRocesses And InfluenceS on the Earth's climate (APPRAISE) project. A narrow but extensive line (~100 km long) of shallow convective clouds over the southern UK was studied. Cloud top temperatures were observed to be higher than −8 °C, but the clouds were seen to consist of supercooled droplets and varying concentrations of ice particles. No ice particles were observed to be falling into the cloud tops from above. Current parameterisations of ice nuclei (IN) numbers predict too few particles will be active as ice nuclei to account for ice particle concentrations at the observed, near cloud top, temperatures (−7.5 °C). The role of mineral dust particles, consistent with concentrations observed near the surface, acting as high temperature IN is considered important in this case. It was found that very high concentrations of ice particles (up to 100 L−1) could be produced by secondary ice particle production providing the observed small amount of primary ice (about 0.01 L−1) was present to initiate it. This emphasises the need to understand primary ice formation in slightly supercooled clouds. It is shown using simple calculations that the Hallett-Mossop process (HM) is the likely source of the secondary ice. Model simulations of the case study were performed with the Aerosol Cloud and Precipitation Interactions Model (ACPIM). These parcel model investigations confirmed the HM process to be a very important mechanism for producing the observed high ice concentrations. A key step in generating the high concentrations was the process of collision and coalescence of rain drops, which once formed fell rapidly through the cloud, collecting ice particles which caused them to freeze and form instant large riming particles. The broadening of the droplet size-distribution by collision-coalescence was, therefore, a vital step in this process as this was required to generate the large number of ice crystals observed in the time available. Simulations were also performed with the WRF (Weather, Research and Forecasting) model. The results showed that while HM does act to increase the mass and number concentration of ice particles in these model simulations it was not found to be critical for the formation of precipitation. However, the WRF simulations produced a cloud top that was too cold and this, combined with the assumption of continual replenishing of ice nuclei removed by ice crystal formation, resulted in too many ice crystals forming by primary nucleation compared to the observations and parcel modelling.

Community engagement and social organization: introducing concepts, policy and practical applications

This chapter provides an introductory overview of how the term ‘community’ has been conceptualized in sociological literatures, noting that there remains considerable uncertainty with regard to the way in which communities could or should be defined. The chapter examines the salience of underlying concepts of social organization that can shape and influence the extent to which programmes of engagement are likely to be successful. Drawing on recent empirical work some of the key opportunities and challenges for local government in translating the concepts into practice are considered.