403 research outputs found
Polymer/montmorillonite nanocomposites with improved thermal properties: Part II. Thermal stability of montmorillonite nanocomposites based on different polymeric matrixes.
In previous part of this work factors influencing the thermal stability of
polymer nanocomposite materials were indicated, such as chemical constitution of
organic modifier, filler content, nanocomposites’ structure and the processing-
dependent degree of homogenization of nanofiller, were presented. In this part
the basic changes in thermal behaviour of different polymeric matrixes (e.g.
polyolefins, polyamides, poly(vinyl chloride) and styrene-containing polymers)
upon addition of montmorillonite have been described. Brief description of the
kinetics of the decomposition process in inert and oxidative environment, as
well as analysis of volatile and condensed products of degradation, have also
been present
Revealing side effects of quota rules on group cooperation
ArticleThe quota rule in employment is a legal tool to promote gender equality in professions and positions where women are underrepresented. An accompanying assumption is that gender diversity positively affects one of the aspects of team performance in form of group cooperation.
However, it is unclear whether this positive effect can be achieved if diversity increases due to a quota rule. In two fully incentivized experiments involving a real-effort task (N1 = 188 and N2 = 268), we examined the impact of quotas as compared to performance-based promotion on group
cooperation. We thereby categorized participants either with regard to gender or to an artificial category that was randomly assigned. Cooperation within groups declined when promotion was based on quota compared to performance-based promotion, irrespective of the categorization
criterion. Further analyses revealed that this negative effect of quota rules on cooperation is not driven by procedural fairness perceptions or expectations about performance of the promoted group member. Implications of the results for the implementation of equality and diversity
initiatives are discussed
Radiation pressure acting on the neutral He atoms in the Heliosphere
The Interstellar Neutral Helium (ISN He) is an important source of
information on the physical state of the Local Interstellar Medium. Radiation
pressure acting on the neutral helium atoms in the heliosphere has always been
neglected, its effect has been considered insignificant compared to
gravitational force. The most advanced numerical models of ISN He take into
account more and more subtle effects, therefore it is important to check if the
effect of radiation pressure is still negligible. In this paper, we use the
most up-to-date version of the Warsaw Test Particle Model (WTPM) to calculate
the expected helium distribution in the heliosphere, and simulate the flux of
ISN He observed by the Interstellar Boundary Explorer (IBEX) and in the future
by the Interstellar Mapping and Acceleration Probe (IMAP). We compare results
calculated with and without radiation pressure during low and high solar
activity. The results show that in the analysis of IBEX-Lo observations the
radiation pressure acting on typical helium causes flux differences at a level
of 1-4% and is comparable to the observational errors. For the more sensitive
IMAP-Lo instrument, there are some regions in the considered observations
configurations where radiation pressure causes potentially statistically
significant changes in the calculated fluxes. The effect can be up to 9% for
the indirect beam and is likely to be higher than the estimated errors.
Therefore, we claim that in the future analysis of the IMAP-Lo observations
radiation pressure acting on ISN He should be considered.Comment: Accepted to Ap
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