Electrorepulsive actuator

The invention is a linear actuator that operates under the principle that like charges repel and opposite charges attract. The linear actuator consists of first and second pairs of spaced opposed conductors where one member of each pair of conductors is attached to a fixed member, and where the other member of each pair of conductors is attached to a movable member such as an elongated rod. The two pairs of spaced conductors may be provided in the form of two spacedly interwound helical vanes where the conductors are located on the opposite sides of the two helical vanes. One helical vane extends inwardly from a housing and the other helical vane extends outwardly from an elongated rod. The elongated rod may be caused to move linearly with respect to the housing by applying appropriate charges of like or opposite polarity to the electrical conductors on the helical vanes

Water tunnel flow visualization using a laser

Laser systems for flow visualization in water tunnels (similar to the vapor screen technique used in wind tunnels) can provide two-dimensional cross-sectional views of complex flow fields. This parametric study documents the practical application of the laser-enhanced visualization (LEV) technique to water tunnel testing. Aspects of the study include laser power levels, flow seeding (using flourescent dyes and embedded particulates), model preparation, and photographic techniques. The results of this study are discussed to provide potential users with basic information to aid in the design and setup of an LEV system

“The electrical charges on Mercury drops in sulphuric acid and other solutons”

Mercury drops falling vertically through an electrolyte may be deflected from their course by application of a horizontal field in the electrolyte. A method of photographing the curve followed by any drop is described, and it is shown possible to deduce the ionic charge on the drop from a study of the shape of the curve. In Sulphuric acid of fixed concentration the drop charge is found to be proportional to its volume. Results are also given for the charges in various acid concentrations between 0.1N and 0.001N. All charges are found to be reduced when the acid is saturated with mercurous sulphate. This seems to afford evidence that, in acid, the charges are due to hydrogen ions, and not to mercurous ions as had been assumed by several investigators. Results obtained in other electrolytes are also given. Some remits for drop charges, measured by a ballistic galvanometer method, are included for comparison. The method is less accurate but confirms the original results. A description is given of similar experiments with amalgam drops. Silver amalgam is similar in behaviour to pure mercury, but Cadmium and Zinc amalgams show a curious phenomenon. The drops are naturally positive, but their charge may be reversed in sign by application of a 'sufficiently strong field. A possible explanation of this, effect is discussed. Some attention is given to the fact { that Zinc and Cadmium appear naturally positive. Several results showing charges in various potential gradients, and. for amalgams of various compositions, are included. A few final pages are devoted to similar experiments using air bubbles and the possibilities of the method for cataphoresis experiments

The consumption of atmospheric methane by soil in a simulated future climate

A recently developed model for the consumption of atmospheric methane by soil (Curry, 2007) is used to investigate the global magnitude and distribution of methane uptake in a simulated future climate. In addition to solving the one-dimensional diffusion-reaction equation, the model includes a parameterization of biological CH<sub>4</sub> oxidation that is sensitive to soil temperature and moisture content, along with specified reduction factors for land cultivation and wetland fractional coverage. Under the SRES emission scenario A1B, the model projects an 8% increase in the global annual mean CH<sub>4</sub> soil sink by 2100, over and above the 15% increase expected from increased CH<sub>4</sub> concentration alone. While the largest absolute increases occur in cool temperate and subtropical forest ecosystems, the largest relative increases in consumption (>40%) are seen in the boreal forest, tundra and polar desert environments of the high northern latitudes. Methane uptake at mid- to high northern latitudes increases year-round in 2100, with a 68% increase over present-day values in June. This increase is primarily due to enhanced soil diffusivity resulting from lower soil moisture produced by increased evaporation and reduced snow cover. At lower latitudes, uptake is enhanced mainly by elevated soil temperatures and/or reduced soil moisture stress, with the dominant influence determined by the local climate

DISTINGUISHING THE SOURCE OF MARKET POWER: AN APPLICATION TO CIGARETTE MANUFACTURING

We compare nonparametric and nonstructural market power tests using data from the cigarette manufacturing industry. Tests are implemented to examine both monopoly and monopsony power exertion by cigarette manufacturers. Results indicate that market power in the tobacco industry, previously attributed to monopoly power exertion, should at least in part be attributed to monopsony market power in the upstream tobacco market.market power, nonparametric, nonstructural, monopsony, monopoly, cigarette manufacturing, Agribusiness,

Estimation of Real-Time Runway Surface Contamination Using Flight Data Recorder Parameters

Within this research effort, the development of an analytic process for friction coefficient estimation is presented. Under static equilibrium, the sum of forces and moments acting on the aircraft, in the aircraft body coordinate system, while on the ground at any instant is equal to zero. Under this premise the longitudinal, lateral and normal forces due to landing are calculated along with the individual deceleration components existent when an aircraft comes to a rest during ground roll. In order to validate this hypothesis a six degree of freedom aircraft model had to be created and landing tests had to be simulated on different surfaces. The simulated aircraft model includes a high fidelity aerodynamic model, thrust model, landing gear model, friction model and antiskid model. Three main surfaces were defined in the friction model; dry, wet and snow/ice. Only the parameters recorded by an FDR are used directly from the aircraft model all others are estimated or known a priori. The estimation of unknown parameters is also presented in the research effort. With all needed parameters a comparison and validation with simulated and estimated data, under different runway conditions, is performed. Finally, this report presents results of a sensitivity analysis in order to provide a measure of reliability of the analytic estimation process. Linear and non-linear sensitivity analysis has been performed in order to quantify the level of uncertainty implicit in modeling estimated parameters and how they can affect the calculation of the instantaneous coefficient of friction. Using the approach of force and moment equilibrium about the CG at landing to reconstruct the instantaneous coefficient of friction appears to be a reasonably accurate estimate when compared to the simulated friction coefficient. This is also true when the FDR and estimated parameters are introduced to white noise and when crosswind is introduced to the simulation. After the linear analysis the results show the minimum frequency at which the algorithm still provides moderately accurate data is at 2Hz. In addition, the linear analysis shows that with estimated parameters increased and decreased up to 25% at random, high priority parameters have to be accurate to within at least ±5% to have an effect of less than 1% change in the average coefficient of friction. Non-linear analysis results show that the algorithm can be considered reasonably accurate for all simulated cases when inaccuracies in the estimated parameters vary randomly and simultaneously up to ±27%. At worst-case the maximum percentage change in average coefficient of friction is less than 10% for all surfaces