Experimental study of vibro-acoustic response of stiffened cylindrical shells

Vibrational response of stiffened cylindrical shell to reverberant acoustic field

Electrostatic instability of ring current protons beyond the plasmapause during injection events

The stability of ring current protons with an injection spectrum modeled by an m = 2 mirror distribution function was examined for typical ring current parameters. It was found that the high frequency loss cone mode can be excited at wave numbers K lambda sub Di about = to 0.1 to 0.5, at frequencies omega about = to (0.2 to 0.6) omega sub pi and with growth rates up to gamma/omega about = to 0.03. These waves interact with the main body of the proton distribution and propagate nearly perpendicular to the local magnetic field. Cold particle partial densities tend to reduce the growth rate so that the waves are quenched at or near to the plasmapause boundary. Wave e-folding lengths are comparable to 0.1 R sub e, compared to the value of about 4 R sub e found for ion cyclotron waves at the same plasma conditions

Wildlife-livestock interactions and risk areas for cross-species spread of bovine tuberculosis

The transmission of diseases between livestock and wildlife can be a hindrance to effective disease control. Maintenance hosts and contact rates should be explored to further understand the transmission dynamics at the wildlife-livestock interface. Bovine tuberculosis (BTB) has been shown to have wildlife maintenance hosts and has been confirmed as present in the African buffalo (Syncerus caffer) in the Queen Elizabeth National Park (QENP) in Uganda since the 1960s. The first aim of this study was to explore the spatio-temporal spread of cattle illegally grazing within the QENP recorded by the Uganda Wildlife Authority (UWA) rangers in a wildlife crime database. Secondly, we aimed to quantify wildlife-livestock interactions and cattle movements, on the border of QENP, using a longitudinal questionnaire completed by 30 livestock owners. From this database, 426 cattle sightings were recorded within QENP in 8 years. Thirteen (3.1%) of these came within a 300 m–4 week space-time window of a buffalo herd, using the recorded GPS data. Livestock owners reported an average of 1.04 (95% CI 0.97–1.11) sightings of Uganda kob, waterbuck, buffalo or warthog per day over a 3-month period, with a rate of 0.22 (95% CI 0.20–0.25) sightings of buffalo per farmer per day. Reports placed 85.3% of the ungulate sightings and 88.0% of the buffalo sightings as further than 50 m away. Ungulate sightings were more likely to be closer to cattle at the homestead (OR 2.0, 95% CI 1.1–3.6) compared with the grazing area. Each cattle herd mixed with an average of five other cattle herds at both the communal grazing and watering points on a daily basis. Although wildlife and cattle regularly shared grazing and watering areas, they seldom came into contact close enough for aerosol transmission. Between species infection transmission is therefore likely to be by indirect or non-respiratory routes, which is suspected to be an infrequent mechanism of transmission of BTB. Occasional cross-species spillover of infection is possible, and the interaction of multiple wildlife species needs further investigation. Controlling the interface between wildlife and cattle in a situation where eradication is not being considered may have little impact on BTB disease control in cattle

A method for determining the characteristic functions associated with the aeroelastic instabilities of helicopter rotors in forward flight

Computer program for determining characteristic functions of aeroelastic instabilities of helicopter rotor in forward fligh

Double window viewing chamber assembly

A viewing chamber which permits observation of a sample retained therein includes a pair of double window assemblies mounted in opposed openings in the walls thereof so that a light beam can directly enter and exit from the chamber. A flexible mounting arrangement for the outer windows of the window assemblies enables the windows to be brought into proper alignment. An electrical heating arrangement prevents fogging of the outer windows whereas desiccated air in the volume between the outer and inner windows prevents fogging of the latter

First principle computation of stripes in cuprates

We present a first principle computation of vertical stripes in $La_{15/8}Sr_{1/8}CuO_4$ within the LDA+U method. We find that Cu centered stripes are unstable toward O centered stripes. The metallic core of the stripe is quite wide and shows reduced magnetic moments with suppressed antiferromagnetic (AF) interactions. The system can be pictured as alternating metallic and AF two-leg ladders the latter with strong AF interaction and a large spin gap. The Fermi surface shows warping due to interstripe hybridization. The periodicity and amplitude of the warping is in good agreement with angle resolved photoemission experiment. We discuss the connection with low-energy theories of the cuprates.Comment: 5 pages,4 figure

Study of zero-gravity, vapor/liquid separators

Heat exchange, mechanical separation, surface tension, and dielectrophoretic methods of separating vapor from liquid at zero gravity for vapor ventin

Wireless Sensor Networks:A case study for Energy Efficient Environmental Monitoring

Energy efficiency is a key issue for wireless sensor networks, since sensors nodes can often be powered by non-renewable batteries. In this paper, we examine four MAC protocols in terms of energy consumption, throughput and energy efficiency. A forest fire detection application has been simulated using the well-known ns-2 in order to fully evaluate these protocols

The Physics of a Sextet Quark Sector

Electroweak symmetry breaking may be a consequence of color sextet quark chiral symmetry breaking. A special solution of QCD is involved, with a high-energy S-Matrix that can be constructed ``semi-perturbatively'' via the chiral anomaly and reggeon diagrams. An infra-red fixed point and color superconductivity are crucial components of the construction. Infinite momentum physical states contain both quarks and a universal ``anomalous wee gluon'' component, and the spectrum is more limited than is required by confinement and chiral symmetry breaking. The pomeron is approximately a regge pole and the Critical Pomeron describes asymptotic cross-sections. The strong coupling of the pomeron to the electroweak sector could produce large $x$ and $Q^2$ events at HERA, and vector boson pairs at Fermilab. Further evidence for the sextet sector at Fermilab would be a large $E_T$ jet excess, due in part to the non-evolution of ${\alpha}_s$, and other phenomena related to the possibility that top quark production is due to the $\eta_6$. The sextet proton and neutron are the only new baryonic states. Sextet states dominate high energy hadronic cross-sections and stable sextet neutrons could produce both dark matter and ultra high energy cosmic rays. The cosmic ray spectrum knee suggests the effective sextet threshold is between Fermilab and LHC energies, with large cross-section effects expected at the LHC. Jet and vector boson cross-sections will be very much larger than expected, and sextet baryons should also be produced. Double pomeron produced states could provide definitive evidence for the existence of the sextet sector in the initial low luminosity running.Comment: Version to be publishe