Analysis and measurements of permanent magnet `bifilar' helicalwigglers

Analysis and measurements of the permanent magnet `bifilar' helical wiggler, composed of a cylindrical array of staggered bar magnets are presented. The discreteness of the magnets is taken into account, thus enabling a calculation of the field strengths of the fundamental and higher spatial harmonics. Calculations show that the performance of this wiggler is expected to be comparable or to better than that of a planar wiggler similar parameters. In addition, samarium-cobalt-iron hybrids in which soft iron tubes were used to enhance and/or taper the wiggler field amplitude were studied experimentally and analytically     

Trans boundary transport of pollutants by atmospheric mineral dust

The transport of anthropogenic pollution by desert dust in the Eastern Mediterranean region was studied by analyzing major and trace element composition, organic species, and Pb isotope ratios in suspended dust samples collected in Jerusalem, Israel. Dust storms in this region are associated with four distinct synoptic conditions (Red Sea Trough (RS), Eastern High (EH), Sharav Cyclone (SC), and Cold Depression (Cyprus low, CD)) that carry dust mostly from North African (SC, CD, EH) and Arabian and Syrian (RS, EH) deserts. Substantial contamination of dust particles by Pb, Cu, Zn, and Ni is observed, while other elements (Na, Ca, Mg, Mn, Sr, Rb, REE, U, and Th) display natural concentrations. Sequential extraction of the abovementioned elements from the dust samples shows that the carbonate and sorbed fractions contain most of the pollution, yet the Al-silicate fraction is also contaminated, implying that soils and sediments in the source terrains of the dust are already polluted. We identified the pollutant sources by using Pb isotopes. It appears that before the beginning of the dust storm, the pollutants in the collected samples are dominated by local sources but with the arrival of dust from North Africa, the proportion of foreign pollutants increases. Organic pollutants exhibit behavior similar and complementary to that of the inorganic tracers, attesting to the importance of anthropogenic-pollutant addition en route of the dust from its remote sources. Pollution of suspended dust is observed under all synoptic conditions, yet it appears that easterly winds carry higher proportions of local pollution and westerly winds carry pollution emitted in the Cairo basin. Therefore, pollution transport by mineral dust should be accounted for in environmental models and in assessing the health-related effects of mineral dust.     

Predicting behavior: Combining intention with investment.

In recent years, several social researchers have focused on ways to improve the prediction of behavior from attitudes. We examined the use of a measure of investment from the Rusbult and Farrell model of commitment as a means for enhancing prediction in the Ajzen and Fishbein intention model. Analysis of data collected from 95 subjects who were asked about their intention to participate in music-related activities over the next week and month showed that investment and its interaction with intention explain additional behavior variance beyond intention alone. The full model consisting of intention, investment, and their interaction explained, for the one-week period, nearly 53% of the criterion variance, and for the one-month period, nearly 78% of the criterion variance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Irradiation induced grain boundary flow-a new creep mechanism at the nanoscale

A new mechanism of irradiation enhanced creep is proposed for nanocrystalline materials. It derives from local relaxations within the grain boundaries as they absorb point defects produced by irradiation. The process is studied by inserting point defects into the grain boundaries and following the materials response by molecular dynamics. Calculated creep compliances are found in good agreement with those measured in dilute nanocrystalline Cu-W alloys [Tai, K.; Averback, R. S.; Bellon, P.; Ashkenazy Y. Scr. Mater.2011, 65, 163]. The simulations provide a direct link between irradiation induced creep in nanocrystalline materials with radiation-induced viscous flow in amorphous materials, suggesting that grain boundaries in these materials can be treated as an amorphous phase. We provide a simple analytic model based on this assumption that reproduces the main features of the observed creep rates, a linear dependence on stress, inverse dependence of grain size, a weak dependence on temperature, and a reasonable estimate of the absolute creep rate.     

Perceived similarity and accuracy of peer ratings.

The hypothesis that raters will be more accurate in rating peers perceived to be similar to themselves, suggested by Mumford (1983) and derived from social comparison theory, was examined. Subjects were 681 Israeli entrants to a military training program. Shortly after course inception, subjects were asked to review the performance of squad members and to forecast their final grade. Subjects also judged peers' similarity to self overall (general similarity), in course achievement (foreground similarity), and in military experience (background similarity). Analysis revealed that accuracy was markedly lower in the evaluation of dissimilar others. Although the same patterns of results was observed for all forms of similarity, stronger effects resulted when similarity was measured in terms of general and foreground characteristics. Implications for future theory and research as well as for the practical application of peer assessment are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)