Maxwell and the science of colour

This non-technical review of Maxwell's contributions to the quantitative theory of colour was presented at a symposium in Aberdeen to celebrate the 150th anniversary of his appointment as professor of natural philosophy at Marischal College. Maxwell maintained his interest in the science of light and colour from his childhood to the last decade of his life. He lavished the same care and imagination on these studies as he did on his epochal contributions to electromagnetism and statistical physics.     

Comparison of the group V and VI transition metal carbides for methane dry reforming and thermodynamic prediction of their relative stabilities

The DME‐SCR activity was suppressed upon exposure of a γ-alumina catalyst to SO₂, in contrast to methanol‐SCR, which remains active at the same surface sulphate coverage. This difference in behaviour is attributed to the limited availability of surface methoxy, which may be regarded as a prerequisite for NOx- reduction over γ-alumina under lean conditions, in the case of dimethyl ether in the presence of SO₂. This revised version was published online in July 2006 with corrections to the Cover Date.     

Composition of chlorinated hydrocarbon contaminants among major adipose tissue depots of polar bears (Ursus maritimus) from the Canadian high Arctic

Monitoring of environmental contaminants in Canadian Arctic polar bears (Ursus maritimus) typically has used superficial adipose tissue samples collected as part of controlled native subsistence hunts. However, little attention has been paid to the compositional difference in contaminants that may exist among the major adipose depots that are routinely collected. To address this knowledge gap, we investigated the profiles and concentrations of chlorinated hydrocarbon contaminants (CHCs), including major polychlorinated biphenyl (PCB) congeners and organochlorine (OC) pesticides and metabolites, in six major adipose depots (i.e. superficial, inter-muscular and intra-abdominal regions) obtained from adult male polar bears in the vicinity of Resolute Bay, Canadian high Arctic. Concentrations and congener patterns of PCBs (20 congeners) and OCs (14 compounds; chlordanes and dichlorodiphenyltrichloroethanes and metabolites, chlorinated benzenes, hexachlorocyclohexane isomers, octachlorostyrene and dieldrin) were found to be relatively uniform throughout the adipose tissue of male polar bears. The only exception was the inter-muscular adipose depot from the cervical region, which was characterized, compared to other major depots routinely sampled, by lower proportions of higher-chlorinated and recalcitrant congeners such as CB170/190, 180, 194 and 206, and higher contribution of the lower-chlorinated PCBs, CB47, 74 and 99. No difference in the OC makeup and concentrations was found among the adipose depots investigated. In view of this, we conclude that the determination of CHCs in adipose tissue of polar bears from any major depots, with the potential exception of the fat under the neck muscles, would give a representative picture of the overall CHC composition and concentrations in polar bear fat for purpose of trend monitoring.     

一种有约束矩形排样问题的求解算法

对属于NP完全问题的有约束矩形排样问题，国内外多采用计算复杂度较小、时间较快、便于控制问题约束条件的启发式方法.分析了启发式排料算法影响优化程度的原因，提出利用回溯寻求优化零件组合的混合启发式策略，并利用排样过程中产生的小剩余区域划分与合并的方法和现有的矩形排样启发式算法相比，说明该方法可以更大地提高板材的利用率.     

Maintaining the security of supply in the Australian national electricity Market with higher levels of renewable energy

This paper examines security of supply concerns in an Australian electricity market under transition and considers potential policy pathways to address them. It details the current state of Australia’s electricity industry, considers the extent to which supply security in the electricity sector may be considered a public good, and examines the features likely to impact on the efficacy of current and potential future market designs.     

Rigid‐Rod Polymers: Synthesis,Processing, Simulation,Structure, and Properties

Synthesis, structure, and properties of rigid‐rod polymers with special emphasis on poly(p‐phenylene benzobisoxazole) (PBO) and poly(p‐phenylene benzobisthiazole) (PBZT) have been reviewed. Recent studies on chemical modifications and molecular simulations have also been given. After nearly 20 years of research and development, PBO fiber was commercialized in the late 1990s. However, due to processing difficulties, the concept of the so called molecular composites has not been successful. Development of the high compressive strength M5 and dihydroxy‐PBI fibers clearly suggest that there is potential for further developing properties of this class of materials. Opto‐electronic properties have also been reviewed.

Synthesis of PBZT.     

Mechanistic Studies of the Solvolyses of Carbamoyl Chlorides and Related Reactions

Carbamoyl chlorides are important intermediates, both in the research laboratory and in industrial scale syntheses. The most studied and used are the disubstituted derivatives, incorporating either aryl or alkyl groups (Ar₂NCOCl or R₂NCOCl). Sometimes, the groups are tied back to give a ring and piperidino- and morpholino-derivatives are commonly encountered. Some studies have been made with two different groups attached. Solvolyses tend to occur at the carbonyl carbon, with replacement of the chloride ion. Studies of both rate and products are reviewed and the solvolysis reactions are usually S_N1, although addition of an amine leads to a superimposable bimolecular component. Many of the studies under solvolytic conditions include the application of the extended Grunwald–Winstein equation. The monosubstituted derivatives (ArNHCOCl or RNHCOCl) are less studied. They are readily prepared by the addition of HCl to an isocyanate. In acetonitrile, they decompose to set up and reach equilibrium with the isocyanate (ArNCO or RNCO) and HCl. Considering that the structurally related formyl chloride (HOCOCl) is highly unstable (with formation of HCl + CO₂), the unsubstituted carbamoyl chloride (H₂NCOCl) is remarkably stable. Recommended synthetic procedures require it to survive reaction temperatures in the 300–400 °C range. There has been very little study of its reactions.     

Taxonomy of interpolation constraints on recursive subdivision curves

Published online: 14 May 2002     

Eliciting information about organizational culture via laddering

Abstract. Eliciting information about organizational culture is an important part of system analysis and design. However, eliciting knowledge of this sort is difficult. Laddering is an established technique that is particularly suitable for eliciting information about goals and for eliciting explanations, which are important issues when investigating organizational culture. This paper describes the method, its strengths and limitations, its use in several case studies and its relation to other elicitation techniques. Recommendations for further work are given.