2,125 research outputs found
Recommended from our members
The problem of pika control in Baluchistand, Pakistan
The collared pika, Ochotona rufescens, has been recorded as a serious pest in apple orchards in the uplands valley of Ziarat in Baluchistan. In the winter, when the natural vegetation is lacking, the pikas debark the apple tree trunks or branches resulting in the killing of the tree and reduced fruit production. In summer, damage to wheat, corn and potatoes is also very severe. It is estimated that pikas cause hundreds of thousands of dollars (US) in annual apple production losses. The apple production in Baluchistan accounts for about 35 percent of the total provincial income through food production. During the six years (1974-1979), the winter of 1973-74 was noted for heavy damage to apple trees and thereafter it declined steadily. The control measures evaluated were of various kinds among which repellent "Ostico" was very effective in protecting the trees. Poison baiting with brodifacoum (0.005%), Vacor (1%) and thallium sulphate (1%) were also effective in reducing the pika population. To alleviate damage caused by pikas, the farmers also practice some traditional protective methods which in some cases are quite effective but very laborious
Bicycling Seminar and Ignatian Pedagogy for Sustainability
In a bicycling First Year Seminar at Xavier University students experience and respond to the Ignatian Pedagogy for Sustainability (IPS) in their final assignments. The IPS is derived from the Ignatian Pedagogy Paradigm of context, experience, reflection, action and evaluation and is being applied to interdisciplinary sustainability teaching in a number of Jesuit institutions currently
Flow around a sphere in a circular tube
The vector potential for the flow of an ideal fluid through a tube containing a concentric spherical obstacle is found for ratios of sphere radius to tube radius of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.95. The flow is confined to the space between sphere and cylinder by thin vortex sheets of variable strength and a table of their circulation intensity on the spherical surface is given. Accuracies vary from about one part in 108 for small spheres to one part in 107 for large ones. The increase in the scalar velocity potential between the ends of the tube caused by the insertion of the sphere is expressed in terms of the effective increase in tube length. This also gives the increase in resistance of a solid conducting cylinder due to the presence of a concentric spherical bubble
Fighting Telemarketing Scams
Interstate telemarketing fraud has become an increasing problem in recent years. Unscrupulous telephone sellers victimize all segments of society, costing consumers tens of billions of dollars each year. Moreover, the costs of this type of fraud extend beyond consumers to credit card companies, banks, and legitimate telemarketers. Most of these con artists are never caught, however, because gaps in enforcement permit them to operate undetected and unprosecuted, and because sanctions against them are often impossible to enforce. This Note discusses the scope of the telemarketing fraud problem, analyzes the limitations of current detection, prosecution, and enforcement mechanisms, and proposes national legislation as a possible solution
<i>Favartia (Favartia) paulboschi</i> (Muricidae: Muricopsinae): a new muricid from Oman
This paper describes a new species of muricid, Favartia paulboschi, from Oman. The shell, operculum and radula are illustrated. This species was first noticed in December 1980 on Masirah, Oman and since then 19 living and 28 dead examples have been recorded from Masirah and the mainland near Muscat, Oman
Improved perfluoroalkylether fluid development
The feasibility of transforming a commercial linear perfluoroalkylether fluid into a material stable in the presence of metals and metal alloys in oxidizing atmospheres at 300 C without the loss of the desirable viscosity temperature characteristics was determined. The approach consisted of thermal oxidative treatment in the presence of catalyst to remove weak links, followed by transformation of the created functional groups into phospha-s-triazine linkages. It it found that the experimental material obtained in 66% yield from the commercial fluid exhibits, over an 8 hr period at 300 C in the presence of Ti(4Al, 4Mn) alloy, thermal oxidative stability better by a factor of 2.6x1000 based on volatiles evolved than the commercial product. The viscosity and molecular weight of the developed fluid are unchanged and are essentially identical with the commercial material. No metal corrosion occurs with the experimental fluid at 300 C
Melting temperature of screened Wigner crystal on helium films by molecular dynamics
Using molecular dynamics (MD) simulation, we have calculated the melting
temperature of two-dimensional electron systems on \AA-\AA helium
films supported by substrates of dielectric constants
at areal densities varying from cm to cm. Our results are in good agreement with the available
theoretical and experimental results.Comment: 4 pages and 4 figure
Numerical modelling of liquid droplet dynamics in microgravity
Microgravity provides ideal experimental conditions for studying highly reactive and under-cooled materials where there is no contact between the sample and the other experimental apparatus. The non-contact conditions allow material properties to be measured from the oscillating liquid droplet response to perturbations. This work investigates the impact of a strong magnetic field on these measurement processes for weakly viscous, electrically conducting droplets. We present numerical results using an axisymmetric model that employs the pseudo-spectral collocation method and a recently developed 3D model. Both numerical models have been developed to solve the equations describing the coupled electromagnetic and fluid flow processes. The models represent the changing surface shape that results from the interaction between forces inside the droplet and the surface tension imposed boundary conditions. The models are used to examine the liquid droplet dynamics in a strong DC magnetic field. In each case the surface shape is decomposed into a superposition of spherical harmonic modes. The oscillation of the individual mode coefficients is then analysed to determine the oscillation frequencies and damping rates that are then compared to the low amplitude solutions predicted by the published analytical asymptotic theory
No anomalous scaling in electrostatic calibrations for Casimir force measurements
In a recent paper (Phys.Rev.A78, 020101(R) (2008)), Kim at al. have reported
a large anomaly in the scaling law of the electrostatic interaction between a
sphere and a plate, which was observed during the calibration of their Casimir
force set-up. Here we experimentally demonstrate that in proper electrostatic
calibrations the scaling law follows the behavior expected from elementary
electrostatic arguments, even when the electrostatic voltage that one must
apply to minimize the force (typically ascribed to contact potentials) depends
on the separation between the surfaces.Comment: Final versio
Thermal oxidative degradation reactions of perfluoroalklethers
The objective of this contract was to investigate the mechanisms operative in thermal and thermal oxidative degradation of Fomblin Z and hexafluoropropene oxide derived fluids and the effect of alloys and additives upon these processes. The nature of arrangements responsible for the inherent thermal oxidative instability of the Fomblin Z fluids has not been established. It was determined that this behavior was not associated with hydrogen end-groups or peroxy linkages. The degradation rate of these fluids at elevated temperatures in oxidizing atmospheres was found to be dependent on the surface/volume ratio. Once a limiting ratio was reached, a steady rate appeared to be attained. Based on elemental analysis and oxygen consumption data, -CF2OCF2CF2O-, not -CF2CF2O-, is one of the major arrangements present. The action of the M-50 and Ti(4 Al, 4 Mn) alloys was found to be much more drastic in the case of Fomblin Z fluids than that observed for the hexalfuoropropane oxide derived materials. The effectiveness of antioxidation/anticorrosion additives, P-3 and phospha-s-triazine, in the presence of metal alloys was very limited at 316 C; at 288 C the additives arrested almost completely the fluid degradation. The phospha-s-triazine appeared to be at least twice as effective as the P-3 compound; it also protected the coupon better. The Ti(4 Al, 4 Mn) alloy degraded the fluid mainly by chain scission processes; this took place to a much lesser degree with M-50
- …