8,021 research outputs found
Photoelectron spectra of fluorine substituted diazanaphthalenes: “Even cases”
The high resolution He 584 Å photoelectron spectra of three diazanaphthalenes and some of their fluorine derivatives are presented. The qualitative model that is used frequently in the discussion of lone-pair level splittings is examined
Splash wave and crown breakup after disc impact on a liquid surface
In this paper we analyze the impact of a circular disc on a free surface
using experiments, potential flow numerical simulations and theory. We focus
our attention both on the study of the generation and possible breakup of the
splash wave created after the impact and on the calculation of the force on the
disc. We have experimentally found that drops are only ejected from the rim
located at the top part of the splash --giving rise to what is known as the
crown splash-- if the impact Weber number exceeds a threshold value
\Weber_{crit}\simeq 140. We explain this threshold by defining a local Bond
number based on the rim deceleration and its radius of curvature,
with which we show using both numerical simulations and experiments that a
crown splash only occurs when , revealing that the rim
disrupts due to a Rayleigh-Taylor instability. Neglecting the effect of air, we
show that the flow in the region close to the disc edge possesses a
Weber-number-dependent self-similar structure for every Weber number. From this
we demonstrate that \Bond_{tip}\propto\Weber, explaining both why the
transition to crown splash can be characterized in terms of the impact Weber
number and why this transition occurs for .
Next, including the effect of air, we have developed a theory which predicts
the time-varying thickness of the very thin air cushion that is entrapped
between the impacting solid and the liquid. Our analysis reveals that gas
critically affect the velocity of propagation of the splash wave as well as the
time-varying force on the disc, . The existence of the air layer also
limits the range of times in which the self-similar solution is valid and,
accordingly, the maximum deceleration experienced by the liquid rim, what sets
the length scale of the splash drops ejected when We>\Weber_{crit}
Hysteretic clustering in granular gas
Granular material is vibro-fluidized in N=2 and N=3 connected compartments,
respectively. For sufficiently strong shaking the granular gas is
equi-partitioned, but if the shaking intensity is lowered, the gas clusters in
one compartment. The phase transition towards the clustered state is of 2nd
order for N=2 and of 1st order for N=3. In particular, the latter is
hysteretic. The experimental findings are accounted for within a dynamical
model that exactly has the above properties
Misinformation perceived as a bigger informational threat than negativity: A cross-country survey on challenges of the news environment
This study integrates research on negativity bias and misinformation, as a comparison of how systematic (negativity) and incidental (misinformation) challenges to the news are perceived differently by audiences. Through a cross-country survey, we found that both challenges are perceived as highly salient and disruptive. Despite negativity bias in the news possibly being a more widespread phenomenon, respondents across the surveyed countries perceive misinformation as a relatively bigger threat, even in countries where negativity is estimated to be more prevalent. In conclusion, the optimism of recent research about people’s limited misinformation exposure does not seem to be reflected in audiences’ threat perceptions
Breaking waves on a dynamic Hele-Shaw beach
We report the formation of quasi-steady beaches and dunes via breaking waves in our tabletop ‘Hele-Shaw’ beach experiment. Breaking waves are generated by a wave maker, and zeolite particles act as sand. The tank is narrow, just over one-particle diameter wide, creating a quasi-2D set-up. Classical breaker types are observed on a time-scale of about a second. Beach formation under breakers occurs on a longer time-scale, and is a matter of minutes for a range of mono-chromatic wave frequencies. Alternating the wave maker motion between two frequencies generally leads to beach formation but occasionally to formation of a stable dune with water on either side. Finally, the Hele-Shaw configuration explored here experimentally lends itself to multi-scale modeling of beach dynamics
Fight or flight? Attributing responsibility in response to mixed congruent and incongruent partisan news in selective exposure media environments
The implementation of the EU directive on information and consultation
Employee consultation in the UK, traditionally part of an event-driven approach taken by employers, is about to be challenged by the introduction of the European Directive of 2005, which essentially advocates a process-driven approach to employee consultation. With reference to two recent case studies, this paper considers whether or not the new Directive may in future lead to a reduction in asymmetry of information and power imbalance which currently lies strongly in employers' favour
Balancing roles: bridging the divide between HRM, employee participation and learning in the Dutch knowledge economy.
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