441 research outputs found
Analysis of Tangential Slot Blowing on F/A-18 Isolated Forebody
The generation of significant side forces and yawing moments on an F/A-18 fuselage through tangential slot blowing is analyzed using computational fluid dynamics. The effects of freestream Mach number, jet exit conditions, jet length, and jet location are studied. The effects of over- and underblowing on force and moment production are analyzed. Non-time-accurate solutions are obtained to determine the steady-state side forces, yawing moments, and surface pressure distributions generated by tangential slot blowing. Time-accurate solutions are obtained to study the force onset time lag of tangential slot blowing. Comparison with available experimental data from full-scale wind-tunnel and subscale wind-tunnel tests are made. This computational analysis complements the experimental results and provides a detailed understanding of the effects of tangential slot blowing on the flowfield about the isolated F/A-18 forebody. Additionally, it extends the slot-blowing database to transonic maneuvering Mach numbers
Finite size effects and magnetic order in the spin-1/2 honeycomb lattice compound InCu{2/3}V{1/3}O{3}
High field electron spin resonance, nuclear magnetic resonance and
magnetization studies addressing the ground state of the quasi two-dimensional
spin-1/2 honeycomb lattice compound InCu{2/3}V{1/3}O{3} are reported.
Uncorrelated finite size structural domains occurring in the honeycomb planes
are expected to inhibit long range magnetic order. Surprisingly, ESR data
reveal the development of two collinear antiferromagnetic (AFM) sublattices
below ~ 20 K whereas NMR results show the presence of the staggered internal
field. Magnetization data evidence a spin reorientation transition at ~ 5.7 T.
Quantum Monte-Carlo calculations show that switching on the coupling between
the honeycomb spin planes in a finite size cluster yields a Neel-like AFM spin
structure with a substantial staggered magnetization at finite temperatures.
This may explain the occurrence of a robust AFM state in InCu{2/3}V{1/3}O{3}
despite an unfavorable effect of structural disorder.Comment: revised version, accepted as a Rapid Communication in Phys. Rev. B
(2010
The incarnation of the Nersesyan-Tsvelik model in (NO)[Cu(NO3)3]
The topology of the magnetic interactions of the copper spins in the
nitrosonium nitratocuprate (NO)[Cu(NO3)3] suggests that it could be a
realization of the Nersesyan-Tsvelik model, whose ground state was argued to be
either a resonating valence bond (RVB) state or a valence bond crystal (VBC).
The measurement of thermodynamic and resonant properties reveals a behavior
inherent to low dimensional spin S = 1/2 systems and provides indeed no
evidence for the formation of long-range magnetic order down to 1.8 K.Comment: 12 pages, 6 figure
The Use of Laparoscopy in the Management of Trauma Patients : Brief review
Laparoscopy is one of the most effective intervention modalities, resulting in improved outcomes for major surgeries. In the past decade, the laparoscopic approach in trauma patients has shown better diagnostic outcomes than traditional laparotomies. Furthermore, this approach is cost-effective, significantly reduces the length of hospital stay and contributes to reduced complication rates. However, the use of laparoscopies in trauma cases is generally restricted to patients with normal haemodynamic parameters and is contraindicated for individuals with head injuries. With advances in knowledge and improved training, laparoscopies can also be used in the treatment of other conditions, such as diaphragmatic injuries and organ lacerations. This article briefly reviews the extent of laparoscopy use and its significance in the management of trauma patients
Molecular markers as a prognostic system for hepatocellular carcinoma
AbstractThe gene expression profile p16, c-erbB-3 and bcl2 in hepatocellular carcinoma (HCC) patients with and without associated HCV infection, was assessed. Forty-eight subjects were included in the study and divided equally into two groups: HCC with and without HCV associated infection. Adjacent paracancerous tissues were assessed as control samples. Correlations with various clinico-pathological parameters of the tumour were assessed: stage, grade, and tumour size. The c-erbB-3 oncogene was expressed in 83.33% (40/48) of the total HCC sample and in 31.25% (15/48) of the noncancerous lesions. C-erbB-3 was expressed in 87.5% (21/24) of the HCC cases with associated HCV infection and in 79.16% (19/24) of the HCC cases without associated HCV infection. Gene expression of c-erbB-3 was significantly correlated with the clinico-pathological parameters of the tumour. P16 gene expression was found in 12.5% (6/48) of the total HCC sample and in 25% (12/48) of the para-cancerous lesions. P16 was expressed in 12.5% (3/24) of HCC cases with and without associated HCV infection. Gene expression of p16 exhibited significant negative correlation with clinico-pathological parameters of the tumour. Bcl2 gene expression was found in 20.8% (10/48) of the total HCC sample and in the para-cancerous lesions. Bcl2 was expressed in 20.8% (5/24) of the HCC cases with and without HCV associated infection. Gene expression of bcl2 did not show significant correlations with the clinico-pathological parameters of the tumour. In conclusion, gene expression profiles of p16 and c-erbB-3 could be used as prognostic molecular markers in HCC
On using micro-clouds to deliver the fog
The cloud is scalable and cost-efficient, but it is not ideal for hosting all applications. Fog computing proposes an alternative of offloading some computation to the edge. Which applications to offload, where to, and when is not entirely clear yet due to our lack of understanding of potential edge infrastructures. Through a number of experiments, we showcase the feasibility and readiness of micro-clouds formed by collections of Raspberry Pis to host a range of fog applications, particularly for network-constrained environments
New variables of separation for particular case of the Kowalevski top
We discuss the polynomial bi-Hamiltonian structures for the Kowalevski top in
special case of zero square integral. An explicit procedure to find variables
of separation and separation relations is considered in detail.Comment: 11 pages, LaTeX with Ams font
Atlas of two-dimensional irreversible conservative lagrangian mechanical systems with a second quadratic integral
This paper aims at the most comprehensive and systematic construction and
tabulation of mechanical systems that admit a second invariant, quadratic in
velocities, other than the Hamiltonian. The configuration space is in general a
2D Riemannian or pseudo-Riemannian manifold and the determination of its
geometry is a part of the process of solution. Forces acting on the system
include a part derived from a scalar potential and a part derived from a vector
potential, associated with terms linear in velocities in the Lagrangian
function of the system. The last cause time-irreversibility of the system. We
construct 41 multi-parameter integrable systems of the type described in the
title mostly on Riemannian manifolds. They are mostly new and cover all
previously known systems as special cases, corresponding to special values of
the parameters. Those include all known cases of motion of a particle in the
plane and all known cases in the dynamics of rigid body. In the last field we
introduce a new integrable case related to Steklov's case of motion of a body
in a liquid. Several new cases of motion in the plane, on the sphere and on the
pseudo-sphere or in the hyperbolic plane are found as special cases.
Prospective applications in mathematics and physics are also pointed out.Comment: Paper to be published in "Journal of Mathematical Physics", Vol. 48,
issue 7, July 200
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