Steady state viscosity and thixotropy of hydrophobically modified hydroxyethyl cellulose ~HMHEC! and nonassociative cellulose water solutions are studied. Although all the samples are shear thinning, only the HMHEC is thixotropic, since the migration of hydrophobes to micelles is controlled by diffusion. The Cross model fits steady state curves. The Mewis model, a phenomenological model that pr...

The usual conclusion in the literature is that sunspots reduce welfare because of the agents’ risk aversion. However, if sunspots can lead to escape from an inferior steady state (poverty trap), this conclusion does not necessarily hold. Escaping trajectories can have much higher welfare than those remaining in the poverty trap. The ex—post welfare effect can be positive for initial conditions ...

This is Part-II of a two-part article that presents analytical solutions to multi-species reactive transport equations coupled through sorption and sequential first-order reactions. In Part-I, we provide the mathematical derivations and in this article we discuss the computational techniques for implementing these solutions. We adopt these techniques to develop a general computer code and use i...

This paper investigates the stability of monetary exchange equilibria and the conditions necessary for an equilibrium of this type to emerge endoge-nously. Previous research on money as a medium of exchange has depended on either initial conditions or steady state conditions to pinpoint equilibria. These approaches are not satisfactory for addressing the issue of emergence, either because the d...

In this paper, genetic programming (GP) is employed to model learning and adaptation in the overlapping generations model, one of the most popular dynamic economic models. Using a model of inflation with multiple equilibria as an illustrative example, we show that our GP-based agents are able to coordinate their actions to achieve the Paretosuperior equilibrium (the low-inflation steady state) ...

Societies under similar geographic and economic conditions and subject to similar external influences nonetheless develop very di↵erent types of states. At one extreme are weak states with little capacity and ability to regulate economic or social relations. At the other are despotic states which dominate civil society. Yet there are others which are locked into an ongoing competition with civi...

This paper explores the dynamic properties of price-based policies in a model of competition between two jurisdictions. Jurisdictions invest over time in infrastructure to increase the quality of the environment, a global public good. They are identical in all respects but one: initial stocks of infrastructure. This is a dynamic type of heterogeneity that disappears in the long run. Therefore, ...

This paper reviews statistical methods for analyzing output data from computer simulations of single systems. In particular, it focuses on the problems of choosing initial conditions and estimating steady-state system parameters. The estimation techniques include the replication/deletion approach, the regenerative method, the batch means method, and the standardized time series method.

The ongoing characterization of hot Jupiters has motivated a variety of circulation models of their atmospheres. Such models must be integrated starting from an assumed initial state, which is typically taken to be a wind-free, rest state. Here, we investigate the sensitivity of hot-Jupiter atmospheric circulation models to initial conditions. We consider two classes of models—shallow-water mod...

An analysis has been developed to model a rotorcraft with power loss. Partial power recovery to a flyaway condition, partial power landing, and autorotation to landing with a complete power loss are considered. An optimal control procedure is implemented to predict the pilot response to the power loss with the objective of minimizing the horizontal and vertical impact velocities in the case of ...