8,662 research outputs found
Tornadoes in a Microchannel
In non-dilute colloidal suspensions, gradients in particle volume fraction
result in gradients in electrical conductivity and permittivity. An externally
applied electric field couples with gradients in electrical conductivity and
permittivity and, under some conditions, can result in electric body forces
that drive the flow unstable forming vortices. The experiments are conducted in
square 200 micron PDMS microfluidic channels. Colloidal suspensions consisted
of 0.01 volume fraction of 2 or 3 micron diameter polystyrene particles in 0.1
mM Phosphate buffer and 409 mM sucrose to match particle-solution density. AC
electric fields at 20 Hz and strength of 430 to 600 V/cm were used. We present
a fluid dynamics video that shows the evolution of the particle aggregation and
formation of vortical flow. Upon application of the field particles aggregate
forming particle chains and three dimensional structures. These particles form
rotating bands where the axis of rotation varies with time and can collide with
other rotating bands forming increasingly larger bands. Some groups become
vortices with a stable axis of rotation. Other phenomena showed include counter
rotating vortices, colliding vortices, and non-rotating particle bands with
internal waves
Happiness Research and Cost-Benefit Analysis
A growing body of research on happiness or subjective well-being (SWB) shows, among other things, that people adapt to many injuries more rapidly than is commonly thought, fail to predict the degree of adaptation and hence overestimate the impact of those injuries on their SWB, and, similarly, enjoy small or moderate rather than significant changes in SWB in response to significant changes in income. Some researchers believe that these findings pose a challenge to cost-benefit analysis, and argue that project evaluation decision-procedures based on economic premises should be replaced with procedures that directly maximize subjective well-being. This view turns out to be wrong or, at best, premature. Cost-benefit analysis remains a viable decision-procedure. However, some of the findings in the happiness literature can be used to generate valuations for cost-benefit analysis where current approaches have proven inadequate.
Neighbouring residue effects on the ^(15)N chemical shifts of some aliphatic dipeptides
The ^(15)N chemical shifts of a number of simple aliphatic dipeptides have been determined in a aqueous solution and while the amine nitrogen shift is independent of the nature of the neighbouring residue, the peptide nitrogen shift shows a marked dependence upon the nature of the adjacent amino-acid
Phase-locked loop with sideband rejecting properties Patent
Phase locked loop with sideband rejecting properties in continuous wave tracking rada
International photovoltaic program. Volume 2: Appendices
The results of analyses conducted in preparation of an international photovoltaic marketing plan are summarized. Included are compilations of relevant statutes and existing Federal programs; strategies designed to expand the use of photovoltaics abroad; information on the domestic photovoltaic plan and its impact on the proposed international plan; perspectives on foreign competition; industry views on the international photovoltaic market and ideas about the how US government actions could affect this market;international financing issues; and information on issues affecting foreign policy and developing countries
The Institutionalisation of Political Power in Africa
Evidently, the failure of Nigeria's President Obasanjo's third term bid and the process through which it was reached is indicative of a growing trend in Africa whereby the formal institutional rules are starting to constrain leaders' behavior and to shape political actors' strategies in new ways. In this case, the major challenge for limiting presidential power in Africa today is making certain that leaders adhere to constitutional limits on their
continued eligibility to contest them.NESG Economic Indicators Vol. 13 (1) 2007: pp. 15-2
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