Chemical Reaction Dynamics within Anisotropic Solvents in Time-Dependent Fields

The dynamics of low-dimensional Brownian particles coupled to time-dependent driven anisotropic heavy particles (mesogens) in a uniform bath (solvent) have been described through the use of a variant of the stochastic Langevin equation. The rotational motion of the mesogens is assumed to follow the motion of an external driving field in the linear response limit. Reaction dynamics have also been probed using a two-state model for the Brownian particles. Analytical expressions for diffusion and reaction rates have been developed and are found to be in good agreement with numerical calculations. When the external field driving the mesogens is held at constant rotational frequency, the model for reaction dynamics predicts that the applied field frequency can be used to control the product composition.Comment: 13 pages, 5 figure

The Secondary Market for Capacity in Natural Gas Transportation

The purpose of this paper is to consider the problem of allocating the costs of a public facility with large fixed costs and increasing returns to scale. A particular case is considered for the natural gas transportation industry. A model for allocating capacity over time is considered. The approach is to find optimal pricing so that social welfare is maximized while the common facility is efficiently used. If individuals have property rights to the capacity of the common facility, the result of the analysis leads to the existence of market-clearing prices through a secondary market for the capacity of the common facility.

Dissipating the Langevin equation in the presence of an external stochastic potential

In the Langevin formalism, the delicate balance maintained between the fluctuations in the system and their corresponding dissipation may be upset by the presence of a secondary, space-dependent stochastic force, particularly in the low friction regime. In prior work, the latter was dissipated self-consistently through an additional uniform (mean-field) friction [Shepherd and Hernandez, J. Chem. Phys., 115, 2430-2438 (2001).] An alternative approach to ensure that equipartition is satisfied relies on the use of a space-dependent friction while ignoring nonlocal correlations. The approach is evaluated with respect to its ability to maintain constant temperature for two simple one-dimensional, stochastic potentials of mean force wherein the friction can be evaluated explicitly when there is no memory in the barriers. The use of a space-dependent friction is capable of providing qualitatively similar results to those obtained previously, but in extreme cases, deviations from equipartition may be observed due to the neglect of the memory effects present in the stochastic potentials.Comment: 9 pages, 5 figures, to appear in J. Chem. Phy

WELFARE LOSSES UNDER ALTERNATIVE OLIGOPOLY REGIMES: THE U.S. FOOD AND TOBACCO MANUFACTURING INDUSTRIES

This article systematically estimates the allocative efficiency losses in the U.S. food and tobacco manufacturing industries under alternative oligopoly pricing regimes using a formal model of oligopoly. Using 1987 data for 44 industries and an industry-wide oligopoly pricing scheme, these losses were estimated at approximately 3% of sales--2% in the food industries and 19% in the tobacco industries. Five additional oligopoly pricing regimes, four of which are price leaderships, are simulated and their results compared and tested relative to the industry-wide pricing regime. Findings underscore the importance of cost structure assumptions and that the impact of the type of oligopoly behavior assumed is not as dramatic when differences in demand and cost specifications are smoothed out.Food and tobacco industries, Market power, Welfare loss, Industrial Organization,

TESTING PROTECTION FOR SALE IN THE FOOD INDUSTRIES

This paper tests the Grossman-Helpman Protection for Sale model using panel data from U.S. food processing industries with endogenous protection, import penetration, and political campaign. The results support the key predictions of the model: organized industries are granted higher protection that decreases with import penetration and the price elasticity of imports. Furthermore, the presence of import quotas raises the level of protection substantially. The estimated weight on aggregate welfare is strikingly similar those found by Goldberg and Maggi (1999) and Gawande and Bandopadhyay (2000), implying that protection is not for sale in these industries.Agribusiness,