16,005 research outputs found
Viewfinder/tracking system for Skylab
Basic component of system is infrared spectrometer designed for manual target acquisition, pointing and tracking, and data-take initiation. System incorporates three main subsystems which include: (1) viewfinder telescope, (2) control panel and electronics assembly, and (3) IR-spectrometer case assembly
Fuse protects circuit from voltage and current overloads
Low-melting resistor connected in series with the load protects the circuit against current overloads. It protects test subjects and patients being monitored by electronic instrumentation from inadvertant overloads of current, and sensitive electronic equipment against high-voltage damage
Electrical Load Protection Device-Patent
Development of in-line fuse device for protection of electric circuits from excessive currents and voltage
The White Screen
There was laughter all around me, and I couldn’t help but join in.
I was at the orphanage, playing ball with a bunch of kids in Addis Ababa, Ethiopia. Despite being a little homesick and barely knowing the language, I was having few problems living here. I loved this place, with its ancient roots and friendly people. I loved hearing the morning’s call to prayer when I woke up. [excerpt
Ms. Marvel: Changing Muslim Representation in the Comic World
Examines the representation of Muslim women in the comic book world, and how Kamala Khan (the titular Ms. Marvel) along with some other characters usher in a new wave of how Muslim women are depicted in comics
Oppositional Defiant Disorder and Aggression in a Young Man with Mental Retardation: Long-Term Treatment in a Community-Based Setting
A longitudinal, intensive treatment program is described that was implemented over an 8-year period in a community-based setting for a young man with mental retardation and oppositional defiant disorder with severe physical aggression. The development of this disorder and its systematic treatment are described, with new components added based on improvement in the individual’s behavior. The individual made steady progress and has maintained good behavioral stability for the final three years of the treatment program. This paper highlights the inherent difficulties of applying empirically validated treatment strategies in community-based settings
A new stellar mixing process operating below shell convection zones following off-center ignition
During most stages of stellar evolution the nuclear burning of lighter to
heavier elements results in a radial composition profile which is stabilizing
against buoyant acceleration, with light material residing above heavier
material. However, under some circumstances, such as off-center ignition, the
composition profile resulting from nuclear burning can be destabilizing, and
characterized by an outwardly increasing mean molecular weight. The potential
for instabilities under these circumstances, and the consequences that they may
have on stellar structural evolution, remain largely unexplored. In this paper
we study the development and evolution of instabilities associated with
unstable composition gradients in regions which are initially stable according
to linear Schwarzschild and Ledoux criteria. In particular, we explore the
mixing taking place under various conditions with multi-dimensional
hydrodynamic convection models based on stellar evolutionary calculations of
the core helium flash in a 1.25 \Msun star, the core carbon flash in a
9.3\,\Msun star, and of oxygen shell burning in a star with a mass of
23\,\Msun. The results of our simulations reveal a mixing process associated
with regions having outwardly increasing mean molecular weight that reside
below convection zones. The mixing is not due to overshooting from the
convection zone, nor is it due directly to thermohaline mixing which operates
on a timescale several orders of magnitude larger than the simulated flows.
Instead, the mixing appears to be due to the presence of a wave field induced
in the stable layers residing beneath the convection zone which enhances the
mixing rate by many orders of magnitude and allows a thermohaline type mixing
process to operate on a dynamical, rather than thermal, timescale. We discuss
our results in terms of related laboratory phenomena and associated theoretical
developments.Comment: accepted for publication in Astrophysical Journal, 9 pages, 8 figure
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