10,458 research outputs found
A numerical technique for analysis of wave drag at lifting conditions
Numerical technique for analysis of wave drag at lifting conditions for supersonic aircraf
Program computes zero lift wave drag of entire aircraft
Computer program computes zero lift wave drag of an entire aircraft including any combination of the wing, body, pods, fins, and carnard. The program computes the external volume of the wing and the axial area distribution of the wing equivalent body
Supersonic aircraft Patent
Design of supersonic aircraft with novel fixed, swept wing planfor
Polymers in long-range-correlated disorder
We study the scaling properties of polymers in a d-dimensional medium with
quenched defects that have power law correlations ~r^{-a} for large separations
r. This type of disorder is known to be relevant for magnetic phase
transitions. We find strong evidence that this is true also for the polymer
case. Applying the field-theoretical renormalization group approach we perform
calculations both in a double expansion in epsilon=4-d and delta=4-a up to the
1-loop order and secondly in a fixed dimension (d=3) approach up to the 2-loop
approximation for different fixed values of the correlation parameter, 2=<a=<3.
In the latter case the numerical results need appropriate resummation. We find
that the asymptotic behavior of self-avoiding walks in three dimensions and
long-range-correlated disorder is governed by a set of separate exponents. In
particular, we give estimates for the 'nu' and 'gamma' exponents as well as for
the correction-to-scaling exponent 'omega'. The latter exponent is also
calculated for the general m-vector model with m=1,2,3.Comment: 13 pages, 5 figure
New Pigeon Pea (\u3cem\u3eCajanus Cajan\u3c/em\u3e) Hybrids With Desirable Forage Traits
Pigeon pea is a tropical forage legume usually sown in mixed pastures with tropical forage grasses. Most of the available cultivars shows erect and tall plants with poor tillering potential, breakable thick stems, low leaf/stem ratios (fresh/dry matter) and low persistence under animal grazing. It shows a high dry matter production, due to low leaf/stem ratios (Barnes & Addo, 1997). Pigeon pea shows good crude protein levels/dry matter (ranging from 14-23%) and regular in vitro digestibility indexes (52-58%) (Karachi & Matata, 1996); animal consumption is affected by high tannin levels of young leaves. Being a self-pollinated species, the variability for forage traits occurs among cultivars available at germplasm banks. No significant variation is observed for any forage character within a given population. Effective selection and releasing of new genetic materials bearing desirable morpho-agronomic and forage traits is mostly dependent on increases of genetic variation, which may be accomplished through artificial crossings between selected parentals. This research work was aimed at the synthesis of new pigeon pea hybrids, hopefully bearing new desirable forage characters
The origin of intergalactic thermonuclear supernovae
The population synthesis method is used to study the possibility of
explaining the appreciable fraction (20^+12_15%) of the intergalactic (no-host)
type Ia supernovae observed in galaxy clusters (Gal-Yam ete al. 2003) by binary
whote dwarf merginngs in the cores of globular clusters. In a typical globular
cluster, the number of merging double white dwarfs is fount to be smaller than
10^{-13} per year per average cluster star during the entire evolution of the
cluster, which is a factor of 3 higher than in a Milky-Way-type galaxy. From 5
to 30% of the merging white dwarfs are dynamically expelled from the cluster
with barycenter velocities up to 150 km/s. SN Ia explosions during the mergers
of binary white dwarfs in dense star clusters may account for \sim 1% of the
total rate of SN Ia in the central parts of galaxy clusters if the baryon mass
fraction in such star clusters is \sim 0.3%.Comment: 8 pages, 3 figs. Astronomy Letters (in press
Non-conservative Evolution of Cataclysmic Variables
We suggest a new mechanism to account for the loss of angular momentum in
binaries with non-conservative mass exchange. It is shown that in some cases
the loss of matter can result in increase of the orbital angular momentum of a
binary. If included into consideration in evolutionary calculations, this
mechanism appreciably extends the range of mass ratios of components for which
mass exchange in binaries is stable. It becomes possible to explain the
existence of some observed cataclysmic binaries with high donor/accretor mass
ratio, which was prohibited in conservative evolution models.Comment: LaTeX, 32 pages, to be published in Astron. Z
Block-Diagonalization and f-electron Effects in Tight-Binding Theory
We extend a tight-binding total energy method to include f-electrons, and
apply it to the study of the structural and elastic properties of a range of
elements from Be to U. We find that the tight-binding parameters are as
accurate and transferable for f-electron systems as they are for d-electron
systems. In both cases we have found it essential to take great care in
constraining the fitting procedure by using a block-diagonalization procedure,
which we describe in detail.Comment: 9 pages, 6 figure
Verbal autopsy of 80,000 adult deaths in Tamilnadu, South India
BACKGROUND: Registration of the fact of death is almost complete in the city of Chennai and not so in the rural Villupuram district in Tamilnadu, India. The cause of death is often inadequately recorded on the death certificate in developing countries like India. A special verbal autopsy (VA) study of 48 000 adult (aged â„ 25 yrs) deaths in the city of Chennai (urban) during 1995â97 and 32 000 in rural Villupuram during 1997â98 was conducted to arrive at the probable underlying cause of death to estimate cause specific mortality. METHODS: A ten day training on writing verbal autopsy (VA) report for adult deaths was given to non-medical graduates with at least 15 years of formal education. They interviewed surviving spouse/close associates of the deceased to write a verbal autopsy report in local language (Tamil) on the complaints, symptoms, signs, duration and treatment details of illness prior to death. Each report was reviewed centrally by two physicians independently. Random re-interviewing of 5% of the VA reports was done to check the reliability and reproducibility of the VA report. The validity of VA diagnosis was assessed only for cancer deaths. RESULTS: Verbal autopsy reduced the proportion of deaths attributed to unspecified and unknown causes from 54% to 23% (p < 0.0001) in urban and from 41% to 26% (p < 0.0001) in rural areas in Tamilnadu for adult deaths (â„ 25). The sensitivity of VA to identify cancer was 95% in the age group 25â69. CONCLUSION: A ten day training programme to write verbal autopsy report with adequate feed back sessions and random sampling of 5% of the verbal autopsy reports for re-interview worked very well in Tamilnadu, to arrive at the probable underlying cause of death reliably for deaths in early adult life or middle age (25â69 years) and less reliably for older ages (70+). Thus VA is practicable for deaths in early adult life or middle age and is of more limited value in old age
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