AN EXPERIMENTAL INVESTIGATION OF YIELD STRESS OF WESTERN CANADIAN COAL WATER FUELS

The concept of a yield value is important to many areas of slurry coal water fuel transport such as in predicting its stability or estimating the pressure requirements for pipe-line start-up and turbulent flow. This paper describes techniques to accurately measure coal water fuel yield point. In order to display a wide variation in coal water fuel properties, slurries made from two Western Canadian coals were made available to CRL for yield point study. The proprietory Salzgiter Industrial AG technology (DENSECOAL) was used for a low volatile or bituminous coal (A) and the CARBOGEL process for a medium volatile bituminous (B).     

Embeddings of Star Graphs into Optical Meshes without Bends

We show an embedding of the star graph into a rectangular optical multichannel mesh ofddimensions such that the embedding has no bends; that is, neighbors in the star graph always differ in exactly one coordinate in the mesh, to facilitate one-hop optical communication. To embed ann-star, the mesh can have any number of dimensionsdbetween 1 andn− 1. The embedding has load 1 and an expansion of at mostn^{d − 1}/d!. The size of the mesh will be at most We optimize the size of the host mesh using clique-partitioning to produce embeddings with expansions as low as unity. In two dimensions, for evenn, the mesh will be no larger thann×n(n− 2)!, and have an expansion of no more than 1 1/(n− 1). Further, we show how we can use a contraction method to efficiently embed the star graph into an optical mesh with near-unity aspect ratios. Contraction on a two-dimensional embedding will yield a mesh of size no larger thann×nfor evennwith a load of (n− 2)!.     

Electrostatic effects of smooth muscle calponin on actin assembly

The contribution of electrostatic interactions to the effects of chicken gizzard calponin on the kinetics of actin polymerization and the bundling of F-actin were characterized by a combination of fluorescence, light-scattering, co-sedimentation, and electron-microscopic methods. Stoichiometric amounts of calponin accelerate actin polymerization in low-ionic-strength solutions, but this effect is diminished at [KCI] = 150 mM. At low ionic strengths, micromolar concentrations of calponin induce the formation of large bundles of actin filaments, and lower concentrations of calponin quench the fluorescence of pyrene-labeled F-actin. The latter effect is related to binding of calponin to F-actin rather than to bundling of the filaments. The concentration of calponin required to bundle a fixed concentration of actin filaments increases with increasing ionic strength, as the average diameter of the bundles decreases. Millimolar concentrations of ATP, GTP or ITP are equally efficient at dispersing actin bundles to single filaments or smaller aggregates, even though a significant fraction of calponin remains bound to F-actin. Our findings show that the binding of calponin to actin is determined at least in part by electrostatic interactions, and that the polycationic nature of calponin is primarily responsible for the formation of F-actin bundles via its ability to reduce the electrostatic repulsion between the negatively charged actin filaments.     

Reaction of α-cellulose with SbCl3–KOH–AsCl3

α-Cellulose dissolves in a mixture of SbCl₃, KOH, and AsCl₃. The resulting product as identified by PMR and infrared spectroscopy is α-D -glucose. This product is unexpected, and an explanation for its formation is suggested.     

Social loafing and group evaluation.

Recent work (e.g., S. Harkins; see PA, Vol 75:20027; K. Szymanski and Harkins; see PA, Vol 75:7410) has suggested that social loafing occurs because participants' outputs cannot be evaluated by the experimenter, by the coactors, or by the participants themselves. This analysis had focused on the output of the individual, but in loafing research, participants work together to produce a group product. However, in this prior work participants have been unable to make anything of this group product, because no standard of comparison has been made available. Several recent formulations (e.g., G. Goethals and J. Darley, 1987) have suggested that the potential for group evaluation could motivate performance. Testing this hypothesis in 2 experiments, 1 using an optimizing task and the other a maximizing task, we found that providing a standard that allowed the "group" to evaluate its performance eliminated the loafing effect. The implications of these findings for current theories of group evaluation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verallgemeinerung desCoulombschen Grundgesetzes

Übersicht Geschlossene Ausdrücke für die Summe der durch gegenseitige Spiegelung an Kugelflächen entstandenen Ladungen. Kapazität der Systeme zweier Kugeln. Krafteinwirkungen bei Kugeln mit konstanten Potentialen und Ladungen (gleiche und verschiedene Vorzeichen). Elektrostatisches Gleichgewicht.Mit 13 Abbildungen