57,966 research outputs found
Several different gas-liquid contactors utilizing centrifugal force
Gas-liquid contactors utilizing centrifugal forc
A two component jet model for the X-ray afterglow flat segment in short GRB 051221A
In the double neutron star merger or neutron star-black hole merger model for
short GRBs, the outflow launched might be mildly magnetized and neutron rich.
The magnetized neutron-rich outflow will be accelerated by the magnetic and
thermal pressure and may form a two component jet finally, as suggested by
Vlahakis, Peng & K\"{o}nigl (2003). We show in this work that such a two
component jet model could well reproduce the multi-wavelength afterglow
lightcurves, in particular the X-ray flat segment, of short GRB 051221A. In
this model, the central engine need not to be active much longer than the
prompt ray emission.Comment: 11 pages, 2 figure; Accepted for publication by ApJ
Two-step Emergence of the Magnetic Flux Sheet from the Solar Convection Zone
We perform two-dimensional MHD simulations on the solar flux emergence. We
set the initial magnetic flux sheet at z=-20,000 km in the convection zone. The
flux sheet rises through the convective layer due to the Parker instability,
however, decelerates beneath the photosphere because the plasma on the flux
sheet piles up owing to the convectively stable photosphere above. Meanwhile,
the flux sheet becomes locally unstable to the Parker instability within the
photosphere, and the further evolution to the corona occurs (two-step emergence
model). We carry out a parameter survey to investigate the condition for this
two-step model. We find that magnetic fluxes which form active regions are
likely to have undergone the two-step emergence. The condition for the two-step
emergence is 10^21 - 10^22 Mx with 10^4 G at z=-20,000 km in the convection
zone.Comment: 41 pages, 15 figures, 1 table, Accepted for publication in Ap
A knowledge-based decision support system for payload scheduling
This paper presents the development of a prototype Knowledge-based Decision Support System, currently under development, for scheduling payloads/experiments on space station missions. The DSS is being built on Symbolics, a Lisp machine, using KEE, a commercial knowledge engineering tool
Do External Auditors Perform a Corporate Governance Role in Emerging Markets? Evidence from East Asia
In emerging markets, the concentration of corporate ownership has created agency conflicts between controlling owners and minority shareholders. Conventional corporate control mechanisms such as boards of directors and takeovers are typically weak in containing the agency problem. This study examines whether external independent auditors could be employed as monitors and as bonding mechanisms to alleviate the agency conflict. Using a broad sample of firms from eight East Asian economies, we document that firms are more likely to employ Big Five auditors when they are more subject to the agency problem imbedded in their ultimate ownership structure. One possible reason that this documented relation between auditor choice and the agency problem is more evident than the inconsistent results using U.S. and U.K. data is that alternative governance mechanisms are limited in East Asia. In addition, among East Asian auditees subject to the agency problem, Big Five auditors charge a higher fee and set a lower audit modification threshold while non-Big Five auditors do not. Taken together, the evidence suggests that Big Five auditors in emerging markets do have a corporate governance role.http://deepblue.lib.umich.edu/bitstream/2027.42/39784/3/wp400.pd
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