Recent studies on flame stabilization of premixed turbulent gases

FLAME stabilization is of importance in the practical design of ramjets and afterburners. It has been studied extensively in recent years, particularly with reference to bluff-body flame-holders. In the present survey we describe the investigations relating to flame holding by bluff bodies as well as new techniques (e.g.,. flame holding by the use of reverse jets) which may prove to be of practical importance in new engine configurations. In Section II we consider the flow field downstream of a bluff-body flame-holder which includes the recirculation zone behind the body and a region of flame spreading farther downstream. Explicit reference is made to crucial experiments which illustrate the nature and magnitude of the velocity field, the physical extent, the temperature, and the gas composition of the recirculation zone. Experimental studies and theoretical predictions of the angle of flame spreading, as well as some observations on unstable flow and the onset of blowoff, will be reviewed. The variation of blowoff velocity with flame-holder design, pressure, and mixture composition is considered briefly in Section III both for single and for adjacent bluff bodies. Also included is a summary of results for blowoff velocities obtained with a reverse-jet flame-holder and with wall recesses. Theoretical studies on the mechanism of flame stabilization form the subject of Section IV. We shall indicate the points on which various proposed models agree and disagree with experiment and attempt to formulate a composite description which is consistent with most of the currently available experimental data both for bluff-body and for reverse-jet flameholders

An evaluation of the Sycamore Tree programme: based on an analysis of Crime Pics II data

Sheffield Hallam University, in conjunction with Manchester Metropolitan University, were commissioned to undertake an evaluation of the Sycamore Tree programme by Prison Fellowship England and Wales, who have been delivering the programme across a wide range of prisons throughout England and Wales over a number of years. This current evaluation builds on a previous report published by Sheffield Hallam University in 2005 which undertook a similar analysis and identified a positive impact on prisoners who had successfully completed the programme

Elastic and inelastic scattering of 40 eV electrons from atomic lead

Differential and integral electron impact cross sections for elastic scattering and for the excitation of the first five states in lead have been determined at 40 eV impact energy. The cross section measurements were placed on the absolute scale by normalizing to the optical f-value of the 6p7s3P1 transition which is the upper state for the 7229 Å, 4057 Å and 3639 Å laser emissions. The integral cross sections for elastic scattering (6p2 3P0) and for the excitation of the 6p2 3P1, 6p2 3P2, 6p2 1D2, and 6p7s 3P0(+6p7s3P1) states are: 44, 0.15, 1.5, 0.05 and 8.4*10^-16 cm^2 respectively

Angular Distribution of Bremsstrahlung Produced by 10-keV and 20-keV Electrons Incident on a Thick Au Target

The relative intensities of the thick-target bremsstrahlung produced by 10-keV and 20-keV electrons incident on Au at forward angles ranging from 0 degrees to 25 degrees are compared. Following corrections for photon absorption within the target, the detected radiation appears to be distributed anisotropically only for photon energies, k, that are approximately equal to the initial energy of the incident electrons, E. The results are compared to the theoretical angular distributions of Kissel et al. [At. Data Nucl. Data Tables 28, 381 (1983)]. The comparison suggests that when k/E is approximately equal to 1, the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the theoretical angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets.Comment: The following article has been accepted by AIP Conference Proceedings (Vol. 1525). After it is published, it will be found at http://proceedings.aip.org

Political animals

In the last few years the animal rights movement has grown out of all recognition. It's now an important political force that challenges our definition of the political

International development in transition

This is the pre-peer reviewed version of the following article: HARMAN, S. and WILLIAMS, D. (2014), International development in transition. International Affairs, 90: 925–941. doi: 10.1111/1468-2346.12148, which has been published in final form at http://dx.doi.org/10.1111/1468-2346.12148International development is in a period of transition. While the outcome of this is still unclear, this article argues that there are at least four areas in which the project of international development is changing. First, there is a debate, especially within the World Bank, about development strategy and how we think about development, particularly in terms of the balance between states and markets. This is evident in the debate over state failure and the new structural economics. Second, there is increasing evidence of a shift in lending, away from projects of 'small' human development, perhaps best encapsulated by the United Nations Millennium Development Goals, towards more transformative 'big' development projects such as infrastructure. Third, 'non-traditional' aid donors and new forms of private philanthropy are playing a more significant role in development financing and this, in turn, offers developing countries a new range of choices about what kinds of development assistance they receive. Fourth, aid relations are changing as a result of the renewed agency of developing states, particularly in sub-Saharan Africa, and shifts towards increased South-South cooperation are growing as evidenced by increased funding from regional development banks and increased trade flows. The article reviews these changes and suggests a series of questions and challenges that arise from them for analysts of international development, developing countries and traditional aid donors. © 2014 The Royal Institute of International Affairs

The Theory of Steady, One-dimensional, Laminar Flame Propagation for One-step Chemical Reactions

The Theory of Steady, One-dimensional, Laminar Flame Propagation for One-step Chemical Reactions. The present status of the theory of one-dimensional, steady, laminar flame propagation for one-step chemical reactions is reviewed with particular emphasis on methods of solution and on the physical processes that dominate observable results