Organochlorine Residues in Suspended Solids Collected from the Mouths of Canadian Streams Flowing into the Great Lakes 1974–1977

Suspended solids were collected from 105 streams on the Canadian side of the Great Lakes during snow melt and spring flow between 1974 and 1977. Analyses were performed for organochlorine and organophosphorus insecticides and three industrial chemicals. All streams sampled contained suspended solids that were contaminated with DDT, its metabolites, and polychlorinated biphenyl (PCB). The highest mean concentrations of ΣDDT (356 μg/kg) occurred in 1974 from streams draining the Niagara Peninsula and entering Lake Ontario; these were correlated to areas of high use on fruit in the past. The highest loadings by lake section, however, were along the north shore of Lake Erie involving a very much larger delivery of suspended solids. The highest concentrations of PCB were on suspended solids entering Lake Ontario in 1974 along the northern (191 μg/kg) and southwestern (172 μg/kg) shore and were associated with the high urban-industrial activity in the megalopolis of Hamilton-Burlington-Oakville-Mississauga-Toronto. However, the highest loadings occurred along Lake St. Clair where two large rivers, the Thames and Sydenham, discharge a much larger volume of suspended solids. The highest individual concentrations of HEOD (dieldrin) were found on suspended solids in two streams entering along the southwestern shoreline of Lake Ontario. However, the highest mean residues on solids for all streams was in waters entering Lake Erie (3 μg/kg) and the highest loadings were into Lake St. Clair. Endosulfan, chlordane, and heptachlor epoxide were detected in some streams entering all five lakes. No aldrin, endrin, mirex, heptachlor, or organophosphorus insecticides were detected.     

Review of The social psychology of reading.

Reviews the book, The Social Psychology of Reading by John Edwards (Ed.) (1981). This volume, unlike many edited books, consists of original papers. Unlike many current volumes in reading, this one addresses broad socio- and psychological correlates of reading achievement. This book is a unique collection of data-based chapters, surveys and reviews. If the aim of the volume was to provide a perspective within which reading can be better understood, the authors have achieved success. It is an excellent reference and has good potential for senior undergraduate or early graduate required reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reaction diffusion and associated nonequilibrium effects in the Au-Co system

Inerdiffusion in two-phase Au-Co couples was investigated using metallographic and elec-tron microprobe analyses. Deviations from local equilibrium at the moving α-@#@ α interface were observed. These deviations were significant for short (1 to 2 h duration) anneals and, as the annealing time increased, the interface compositions approached the equilibrium val-ues. The interdiffusion coefficients (~D) and intrinsic diffusivities (D_Au and D_Co) in the α-Au terminal solid solution at 950° and 900°C were determined.     

Cover Picture: A Germanium Inverse Woodpile Structure with a Large Photonic Band Gap (Adv. Mater. 12/2007)

Germanium inverse woodpile 3D photonic crystals with a large (25%) photonic band gap in the infrared (background image) were fabricated through a multistep replication procedure. A polymer scaffold was first created by direct‐write assembly, followed by the conformal growth of oxide and semiconductor layers, and removal of the polymer and oxide (foreground), as reported on p. 1567 by Paul Braun, Jennifer Lewis, and co‐workers.     

Environmentally assisted cracking of aluminium alloys

A short review of the stress corrosion cracking (SCC) behaviour of aluminium alloys is given. Mechanisms of environmentally assisted cracking are outlined. For aluminium alloys, in which stress corrosion cracks propagate predominantly along grain boundaries, anodic dissolution and hydrogen embrittlement have been proposed. Transgranular stress corrosion cracking occurring at severe loading conditions has found particular interest concerning localised corrosion‐deformation interactions. Accelerated test methods for assessing the SCC behaviour are described, including the slow strain rate testing technique and the breaking load method. Results of recent studies on environmentally assisted cracking of aluminium alloys are summarised. Most of the work published in the last two decades has been on aluminium‐lithium based alloys and improved high strength Al‐Zn‐Mg‐Cu alloys in corrosion resistant retrogressed and re‐aged tempers.     

A 'Model-on-Demand' identification methodology for non-linear process systems

An identification methodology based on multi-level pseudo-random sequence (multi-level PRS) input signals and 'Model-on-Demand' (MoD) estimation is presented for single-input, single-output non-linear process applications. 'Model-on-Demand' estimation allows for accurate prediction of non-linear systems while requiring few user choices and without solving a non-convex optimization problem, as is usually the case with global modelling techniques. By allowing the user to incorporate a priori information into the specification of design variables for multi-level PRS input signals, a sufficiently informative input-output dataset for MoD estimation is generated in a 'plant-friendly' manner. The usefulness of the methodology is demonstrated in case studies involving the identification of a simulated rapid thermal processing (RTP) reactor and a pilot-scale brine-water mixing tank. On the resulting datasets, MoD estimation displays performance comparable to that achieved via semi-physical modelling and semi-physical modelling combined with neural networks. The MoD estimator, however, achieves this level of performance with substantially lower engineering effort.