Carrier correlation effects in a quantum-well semiconductor lasermedium

This paper describes the results of a microscopic treatment of carrier-carrier scattering effects in the optical gain and refractive index spectra of a quantum-well semiconductor laser structure. The approach uses the Semiconductor Maxwell Bloch equations to describe the interaction between the carriers and the laser field, in the presence of many-body Coulomb interactions. Coulomb correlation effects are treated at the level of quantum kinetic theory in the Markovian limit. This approach shows the presence of nondiagonal Coulomb correlation contributions, in addition to the familiar diagonal contributions giving rise to polarization dephasing     

A review of heat pipe systems for heat recovery and renewable energy applications

Advancements into the computational studies have increased the development of heat pipe arrangements, displaying multiphase flow regimes and highlighting the broad scope of the respective technology for utilization in passive and active applications. The purpose of this review is to evaluate current heat pipe systems for heat recovery and renewable applications utility. Basic features and limitations are outlined and theoretical comparisons are drawn with respect to the operating temperature profiles for the reviewed industrial systems. Working fluids are compared on the basis of the figure of merit for the range of temperatures. The review established that standard tubular heat pipe systems present the largest operating temperature range in comparison to other systems and therefore offer viable potential for optimization and integration into renewable energy systems.     

Self Assembly–Assisted Additive Manufacturing: Direct Ink Write 3D Printing of Epoxy–Amine Thermosets

The use of self‐assembling, pre‐polymer materials in 3D printing is rare, due to difficulties of facilitating printing with low molecular weight species and preserving their reactivity and/or functions on the macroscale. Akin to 3D printing of small molecules, examples of extrusion‐based printing of pre‐polymer thermosets are uncommon, arising from their limited rheological tuneability and slow reactions kinetics. The direct ink write (DIW) 3D printing of a two‐part resin, Epon 828 and Jeffamine D230, using a self‐assembly approach is reported. Through the addition of self‐assembling, ureidopyrimidinone‐modified Jeffamine D230 and nanoclay filler, suitable viscoelastic properties are obtained, enabling 3D printing of the epoxy–amine pre‐polymer resin. A significant increase in viscosity is observed, with an infinite shear rate viscosity of approximately two orders of magnitude higher than control resins, in addition to, an increase in yield strength and thixotropic behavior. Printing of simple geometries is demonstrated with parts showing excellent interlayer adhesion, unachievable using control resins.     

Discrediting in a Message Board Forum: The Effects of Social Support and Attacks on Expertise and Trustworthiness

Given the prevalence of online media today, credibility continues to be a popular subject of empirical research. However, studies examining the effects of discrediting strategies are rare. This issue is significant given the popularity of online media and the ease of such sources to spread misinformation. Therefore, the present study examines the effects of attacking the expertise and trustworthiness of a proponent of a major social issue. Results showed that support as well specific combinations of discrediting attack strategies significantly reduced message board readers' perceptions of the proponent's credibility. In addition, attacks on either the proponent's expertise or trustworthiness resulted in a reduced likelihood of readers taking action with respect to the issue.     

Megasonic agitation for enhanced electrodeposition of copper

In this paper we propose an agitation method based on megasonic acoustic streaming to overcome the limitations in plating rate and uniformity of the metal deposits during the electroplating process. Megasonic agitation at a frequency of 1 MHz allows the reduction of the thickness of the Nernst diffusion layer to less than 600 nm. Two applications that demonstrate the benefits of megasonic acoustic streaming are presented: the formation of uniform ultra-fine pitch flip-chip bumps and the metallisation of high aspect ratio microvias. For the latter application, a multi-physics based numerical simulation is implemented to describe the hydrodynamics introduced by the acoustic waves as they travel inside the deep microvias.     

Durability of fire retardant treated wood products at humid and exterior conditions review of literature

Fire retardants may considerably improve the fire properties of wood products, but the durability, e.g. in exterior applications, has not been addressed fully. This paper reviews the existing knowledge and experience mainly from the USA with the aim of supporting further development in Europe. The review is concentrated on pressure impregnated fire retardant treated wood products which have the best opportunities for increased durability. Copyright © 2001 by John Wiley & Sons, Ltd.     

Europe as Consumer of Exotic Biodiversity: Greek and Roman times

Landscapes at the edge of the city comprise vast areas that ‘lie fallow’, awaiting future urban development. During this time new landscape values evolve. It is argued that the complexity of urban fringe landscapes is not adequately considered either within landscape research or in the practice of spatial planning. A key to understanding landscapes at the inner urban fringe is to focus on landscape dynamics, and on the interactions between spatial plans and everyday activities. The study is divided into three parts. First, theoretical considerations about landscape dynamics and the character of the inner urban fringe are presented. Thereafter, the relationship between spatial planning and everyday places is analysed in a case-study area at the edge of the city of Malmö in southernmost Sweden. The case study demonstrates the complexity of landscape dynamics at the inner urban fringe, as well as problems regarding the handling of ephemeral and transitory aspects within spatial planning. The study concludes with a discussion concerning the importance of studies of landscape dynamics within landscape research.     

Book reviews

RESOURCE TRENDS AND POPULATION POLICY: A TIME FOR REASSESSMENT, by Lester R. Brown. Worldwatch Institute, Washington, D.C., May 1979; Worldwatch Paper 29. (Paperback $2.00)

THE NEXT SEVENTY YEARS: POPULATION, FOOD AND RESOURCES, by B. Gil‐land. Abacus Press, London, 1979. 133 pp. (£9.50)

POPULATION POLICY ANALYSIS, edited by M. E. Kraft and M. Schneider. D. C. Heath, London, 1979. (£0.00)

ENVIRONMENTAL IMPACT ASSESSMENT, by Brian B. Clark, Ronald Bisset and Peter Wath‐ern. Manssell, London and Bowker, New York, 1980. 516 pp. (£0.00)

ADVANCES IN ECOLOGICAL RESEARCH, Vol. 11, edited by Amyan MacFadyen. Academic Press, London, 1980. 428 pp. (£25.00)

MICROBIAL GROWTH AND SURVIVAL IN EXTREMES OF ENVIRONMENT, edited by G. W. Gould and Janet E. Cory. Academic Press, London, 1980. 244 pp. (£16.00)

UNDER NEW MANAGEMENT: Port Growth and Emerging Coastal Management Programs, by Marc Hershman, Robert Goodwin, Andrew Ruot‐sala, Maureen McCrea and Yehuda Hayuth. A Washington Sea Grant Publication, 1978. 212 pp. ($12.50)

HANDBOOK OF INDUSTRIAL ENERGY ANALYSIS, by J. Boustead and G. F. Hancock. Ellis‐Harwood, Chichester, U.K., 1979. (£25.00)

TREE GROWTH AND ENVIRONMENTAL STRESSES, by T. T. Kozlowski. University of Washington Press, Seattle and London, 1979. vii + 192 pp. (£12.50)

ALL GOOD THINGS AROUND US, by Pamela Michael. Illustrated by Christabel King. Ernest Benn Ltd., London, 1980. 240 pp. (£12.95)

HUMAN GEOGRAPHY (2nd Edition), by A. V. Perpillou. Longman Group, London, U.K., 1977. xviii + 570 pp. 37 pls., 27 maps and diagrams, Index. (Paperback £5.50)

INDUSTRIAL AND HAZARDOUS WASTES IMPOUNDMENT, by N. P. Cheremisinoff, P. N. Cheremisinoff, F. Ellerbeck and A. J. Perna. Ann Arbor Science, Michigan, 1979. ix + 475 pp. Index. (£16.25)

PHOSPHORUS IN THE ENVIRONMENT: ITS CHEMISTRY AND BIOCHEMISTRY. (Ciba Foundation No. 57, New Series), by Ruth Porter and David W. Fitzsimons. Elsevier, 1978. (£18.15)

TOXIC AND HAZARDOUS WASTE DISPOSAL. Vol. II, edited by R. B. Pojasek (Options for Sterilization Solidifications). Ann Arbor Science, Michigan, U.S.A., 1979, 259 pp. (£19.80)

SON OF THE WILDERNESS (The Life of John Muir), by Linnie Marsh Wolfe. The University of Wisconsin Press, Madison, 1978. 364 pp. (Paperback £4.90)

NATURE'S PRICE, by W. van Dieren and M. G. W. Hummelinck. Marion Boyars, London, Boston, 1979. (Paperback £3.50)

PERMACULTURE ONE, by Bill (B. C.) Molli‐son and David Holmgren. Corgi Books, Trans‐world Publishers Ltd., Melbourne, Australia. 128 pp. (A $4.95)

ENVIRONMENTAL AERODYNAMICS, by R. S. Scorer. Ellis Horwood, Chichester, U.K., 1978. 488 pp. (Hardback £20.00; paperback £7.50)