ECONOMIC IMPACTS OF CALIFORNIA'S GOLF COURSE FACILITIES IN 2000

People spent $4.350 billion at California golf course facilities in 2000. The total sales, income, and tax impacts on the state economy were$7.872 billion, $4.546 billion, and$1.370 billion in 2000. Direct sales of $4.251 billion directly supported 62,173 jobs, and , through indirect and induced sales impacts, an additional 37,609 jobs.Land Economics/Use,

Nanoadhesion of elastic bodies : roughness and temperature effects

We present a simple model which illustrates the nature of the contact between an elastic solid and a hard surface with cosine-corrugation profile. In the continuum limit, the contact mechanics depends only on two dimensionless parameters, namely the ratio between the height and wavelength of the substrate corrugation, and the ratio between a surface energy and an elastic energy. The theory shows that the complete contact state is always a local energy minima (in the zero temperature limit), but for large enough surface roughness the global minima correspond to a partial contact state. We show that at nonzero temperature, the contribution to the free energy from the vibrational entropy is very important, and favors the detached state. Computer simulations results are also presented where we study more complicated roughness geometries and the influence of temperature on the adhesion. Simulation results agrees well with the analytical predictions. (C) 2003 American Institute of Physics

Theory and simulations of squeeze-out dynamics in boundary lubrication

The dynamics of expulsion of the last liquidlike monolayer of molecules confined between two surfaces (measured recently for the first time [J. Chem. Phys. 114, 1831 (2001)]) has been analyzed by solving the two-dimensional Navier-Stokes equation combined with kinetic Monte Carlo simulations. Instabilities in the boundary line of the expelled film produce a rough boundary for all length scales above a critical value. The squeeze-out of liquid is shown to result from the 2D-pressure gradient in the lubrication film in the contact area. The Monte Carlo simulations agrees well with experiments, reproducing most qualitative and quantitative features. In particular it shows the formation of small islands, which (in the absence of pinning mechanism) drift slowly to the periphery of the contact area. We calculate the drift velocity analytically as a function of the distance of the island to the periphery of the contact area. Experiments indicate that some kind of pinning mechanism prevails, trapping fluid pockets for very long times. When including such pinning areas in the simulations, three distinct squeeze phases and time scales were observed: (1) initial fast squeeze of most of the fluid; (2) slower squeeze of unpinned fluid pockets; (3) long term pinning of fluid pockets. We also show that a distribution of small pinning areas may produce a synergistic effect, slowing down the second phase of the squeeze, compared to a small number of big pinning areas. The paper presents a new stochastic numerical approach to problems of moving boundaries which naturally accounts for thermal fluctuations and their effect in unstable dynamics. (C) 2001 American Institute of Physics

Non-Kolmogorov atmospheric turbulence and optical signal propagation

International audienceIn the present review, we make an attempt to attract attention to the effect of non-Kolmogorov behavior of turbulence in various scales on the characteristics of electromagnetic waves propagation through a turbulent atmosphere on the example of certain atmospheric experiments. We discuss the interpretation of experimental data based on the model of spectral behavior of a passive scalar field within a broad range of scales, which has been developed recently