32,362 research outputs found
Transport of First Rocks of The Solar System by X-winds
It has been suggested that chondrules and calcium-aluminum-rich inclusions
(CAIs) were formed at the inner edge of the protoplanetary disk and then
entrained in magnetocentrifugal X-winds. We study trajectories of such solid
bodies with the consideration of the central star gravity, the protoplanetary
disk gravity, and the gas drag of the wind. The efficiency of the gas drag
depends on a parameter , which is the product of the solid body size and
density. We find that the gravity of the protoplanetary disk has a
non-negligible effect on the trajectories. If a solid body re-enters the flared
disk, the re-entering radius depends on the stellar magnetic dipole moment, the
disk's gravity, the parameter , and the initial launching angle. The
disk's gravity can make the re-entering radius lower by up to 30%. We find a
threshold , denoted as , for any particular configuration of the
X-wind, below which the solid bodies will be expelled from the planetary
system. sensitively depends on the initial launching angle, and also
depends on the mass of the disk. Only the solid bodies with a larger
than but very close to can be launched to a re-entering radius larger
than 1 AU. This size-sorting effect may explain why chondrules come with a
narrow range of sizes within each chondritic class. In general, the size
distributions of CAIs and chondrules in chondrites can be determined from the
initial size distribution as well as the distribution over the initial
launching angle.Comment: Accepted for publication in Ap
Ethnic Studies in Academe: Challenges and Prospects for the 21st Century. NAES Plenary Session , Kansas City,1995 Missouri, March 19, 1994
The primary intent of organizing the plenary that follows was to engage a number of dedicated and experienced ethnic studies scholar-activists in a focused conversation on the current state of ethnic studies in the academy. At this point many of us have been involved in ethnic studies for more than twenty years. The perspectives and observations offered in this monograph are transcribed from the recordings of the plenary. It offers the reader a far-ranging discussion of the field, its history, its struggles, its pedagogy, and some of its underlying principles
Oil quality in diesel engines with on line oil cleaning using a heated lubricating oil recycler
A method of cleaning the oil on line was investigatedusing a bypass fine particulate filter followed by an infra
red heater to remove water and light diesel fractions in
the oil. This was tested on a range of on road vehicles
and a Ford 1.8 litre IDI passenger car engine on a test
bed. Comparison was made with the oil quality on the
same vehicles and engines without the on-line recycler.
Test times were from 200 to 1500 hours of oil ageing and
some of the tests showed that the oil quality was still
good after 4 times the normal oil life. The results showed
that the on line oil recycler cleaning system reduced the
rate of fall of the TBN and rate of increase of the TAN.
There was a very significant reduction in the soot in oil
and the fuel dilution. There was also a consistent reduction
in all the wear metals apart from copper and a
decrease in the rate of reduction of oil additives. There
was also measured on the Ford IDI engine a 5% reduced
fuel consumption. Many of these effects were attributed
to an influence of the cleaner oil on reduced engine
deposits
Local field distribution near corrugated interfaces: Green's function formulation
We have developed a Green's function formalism to compute the local field
distribution near an interface separating two media of different dielectric
constants. The Maxwell's equations are converted into a surface integral
equation; thus it greatly simplifies the solutions and yields accurate results
for interfaces of arbitrary shape. The integral equation is solved and the
local field distribution is obtained for a periodic interface.Comment: Presented at the Conference on Computational Physics (CCP2000), held
at Gold Coast, Australia from 3 - 8, December 2000. To be published in
Proceedings of CCP200
Oil quality in diesel engines with on line oil cleaning using a heated lubricating oil recycler
A method of cleaning the oil on line was investigatedusing a bypass fine particulate filter followed by an infra
red heater to remove water and light diesel fractions in
the oil. This was tested on a range of on road vehicles
and a Ford 1.8 litre IDI passenger car engine on a test
bed. Comparison was made with the oil quality on the
same vehicles and engines without the on-line recycler.
Test times were from 200 to 1500 hours of oil ageing and
some of the tests showed that the oil quality was still
good after 4 times the normal oil life. The results showed
that the on line oil recycler cleaning system reduced the
rate of fall of the TBN and rate of increase of the TAN.
There was a very significant reduction in the soot in oil
and the fuel dilution. There was also a consistent reduction
in all the wear metals apart from copper and a
decrease in the rate of reduction of oil additives. There
was also measured on the Ford IDI engine a 5% reduced
fuel consumption. Many of these effects were attributed
to an influence of the cleaner oil on reduced engine
deposits
Smart Content Recognition from Images Using a Mixture of Convolutional Neural Networks
With rapid development of the Internet, web contents become huge. Most of the
websites are publicly available, and anyone can access the contents from
anywhere such as workplace, home and even schools. Nevertheless, not all the
web contents are appropriate for all users, especially children. An example of
these contents is pornography images which should be restricted to certain age
group. Besides, these images are not safe for work (NSFW) in which employees
should not be seen accessing such contents during work. Recently, convolutional
neural networks have been successfully applied to many computer vision
problems. Inspired by these successes, we propose a mixture of convolutional
neural networks for adult content recognition. Unlike other works, our method
is formulated on a weighted sum of multiple deep neural network models. The
weights of each CNN models are expressed as a linear regression problem learned
using Ordinary Least Squares (OLS). Experimental results demonstrate that the
proposed model outperforms both single CNN model and the average sum of CNN
models in adult content recognition.Comment: To be published in LNEE, Code: github.com/mundher/NSF
Observation of one electron charge in an enhancement-mode InAs single electron transistor at 4.2K
We propose and demonstrate experimentally a novel design of single-electron
quantum dots. The structure consists of a narrow band gap quantum well that can
undergo a transition from the hole accumulation regime to the electron
inversion regime in a single-top-gate transistor configuration. We have
observed large size quantization and Coulomb charging energies over 10meV. This
quantum dot design can be especially important for scalable quantum computing.Comment: 5 figure
Modelling and predicting fatigue crack growth in structural adhesive joints
The present paper examines crack growth in a range of structural adhesive joints under cyclic-fatigue loadings. It is shown that cyclic-fatigue crack-growth in such materials can be modelled by a form of the Hartman and Schijve crack-growth equation which aims to give a unique and linear ‘master’ representation for the fatigue data points that have been experimentally obtained. This relationship is shown to capture the experimental data representing the effects of test conditions, such as the R-ratio (=σmin /σmax) present in the fatigue cycle and test temperature. It also captures the typical scatter often seen in such tests, especially at low values of the fatigue crack-growth rate. Furthermore, the methodology is shown to be applicable to, and to unify, the results from Mode I (opening tensile), Mode II (in-plane shear) and Mixed-Mode I/II fatigue tests. Finally, it is used to predict successfully the rate of fatigue crack-growth in two bonded-repair type joints where naturally-occurring disbonds have initiated and grown
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