24,998 research outputs found
VALUE AND VALUES - WHAT MOTIVATES CORPORATE CITIZENSHIP IN SOUTH AFRICA?
The expectation that business has a responsibility to the immediate communities in which they operate and to national development imperatives has become entrenched in society. Globally, businesses have responded by embracing the discourse and practice of corporate social responsibility (CSR), albeit at different levels. Such responses have been shaped by local business cultures and the national economic and political contexts.The discourse on CSR or corporate social investment (CSI) has ascended to global prominence, and there are numerous definitions of what it consists of. However, emerging and common themes point towards legislative compliance, meeting stakeholder expectations and contributing to the upliftment of the broader society while increasing and sustaining business profitability
An investigation of combustion instability in aircraft-engine reheat systems
The principal objective of this study was to examine experimentally
the effects of upstream temperature, velocity, gutter blockage, tailpipe
length, and main and pilot fuel flows, on the form of combustion instability
encountered in aircraft reheat systems which is sometimes referred to as 'buzz'.
Tests were carried out at atmospheric pressure for upstream temperatures of
between 200 and 500°C, and upstream velocities ranging from 140 to 200 ft/sec.
Three values of stabilizer blockage were employed, namely 25, 30 and 35%.
The tailpipe length was varied between 9 and 45 inches. Auto-correlation
techniques were used in the frequency analysis of the buzz waveforms.
It was found that a certain minimum tailpipe length is necessary in
order to produce buzz which is then strengthened as the tailpipe length is
increased. Buzz also becomes more pronounced with an increase in gas velocity
but stabilizer blockage appears to have no discernible effect … [cont.]
The Solar Neighborhood VIII: Discovery of New High Proper Motion Nearby Stars Using the SuperCOSMOS Sky Survey
Five new objects with proper motions between 1.0 arcsec/yr and 2.6 arcsec/yr
have been discovered via a new RECONS search for high proper motion stars
utilizing the SuperCOSMOS Sky Survey. The first portion of the search,
discussed here, is centered on the south celestial pole and covers declinations
-90 degrees to -57.5 degrees.
Photographic photometry from SuperCOSMOS and JHKs near-infrared photometry
from 2MASS for stars nearer than 10 pc are combined to provide a suite of new
M_Ks-color relations useful for estimating distances to main sequence stars.
These relations are then used to derive distances to the new proper motion
objects as well as previously known stars with mu >= 1.0 arcsec/yr (many of
which have no trigonometric parallaxes) recovered during this phase of the
survey.
Four of the five new stars have red dwarf colors, while one is a nearby white
dwarf. Two of the red dwarfs are likely to be within the RECONS 10 pc sample,
and the white dwarf probably lies between 15 and 25 pc. Among the 23 known
stars recovered during the search, there are three additional candidates for
the RECONS sample that have no trigonometric parallaxes.Comment: 17 pages, 5 figures; accepted for publication in Astronomy Journa
The formation of glycocyamine in man and its urinary excretion
Glycocyamine was first isolated from human and dog urine and identified by Weber (1-3). He supported the view that glycocyamine is a normal precursor of creatine and that its appearance in urine (2) is “an overflow phenomenon of an intermediate metabolic product ...” He expressed no views on the mechanism of its formation
Sun-Like Magnetic Cycles in the Rapidly-Rotating Young Solar Analog HD 30495
A growing body of evidence suggests that multiple dynamo mechanisms can drive
magnetic variability on different timescales, not only in the Sun but also in
other stars. Many solar activity proxies exhibit a quasi-biennial (2
year) variation, which is superimposed upon the dominant 11 year cycle. A
well-characterized stellar sample suggests at least two different relationships
between rotation period and cycle period, with some stars exhibiting long and
short cycles simultaneously. Within this sample, the solar cycle periods are
typical of a more rapidly rotating star, implying that the Sun might be in a
transitional state or that it has an unusual evolutionary history. In this
work, we present new and archival observations of dual magnetic cycles in the
young solar analog HD 30495, an 1 Gyr-old G1.5V star with a rotation
period near 11 days. This star falls squarely on the relationships established
by the broader stellar sample, with short-period variations at 1.7 years
and a long cycle of 12 years. We measure three individual long-period
cycles and find durations ranging from 9.6-15.5 years. We find the short-term
variability to be intermittent, but present throughout the majority of the time
series, though its occurrence and amplitude are uncorrelated with the longer
cycle. These essentially solar-like variations occur in a Sun-like star with
more rapid rotation, though surface differential rotation measurements leave
open the possibility of a solar equivalence.Comment: 12 pages, 6 figures. Submitted to Ap
Flight tests of a direct lift control system during approach and landing
Flight tests of modified aileron direct lift control system during approach and landing of F8-C aircraf
The oxidation of ascorbic acid and its reduction in vitro and in vivo
The outstanding chemical property of ascorbic acid (vitamin C) is that it is a reducing agent. The suggestion is obvious that its physiological function may be associated with this property, and, if it is oxidized reversibly, with its behavior in an oxidation-reduction system. It is desirable therefore to know the oxidation-reduction potential of ascorbic acid
Orientation filtering by growth-velocity competition in zone-melting recrystallization of silicon on SiO_2
We describe a method of controlling the in-plane directions of grains in (100)-textured silicon films produced by zone-melting recrystallization over amorphous SiO2. Grains having in-plane orientation within a narrow range are able to grow through an orientation filter consisting of a pattern of crystallization barriers, while grains having other orientations are occluded. The results of experiments using an orientation filter, and the parameters which optimize filter performance, are reported
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