The goal of Howitt’s positive mathematical programming procedure is to calibrate a mathematical programming model so that it will reproduce a set of base data for the primal variables. This article develops an analogous procedure allowing one to specify the levels of both primal and dual variables. This article also sheds light on a potential ambiguity of Howitt’s procedure (with attendant poli...

Interspecific competition for resources is generally considered to be the selective force driving ecological character displacement, and displacement is assumed to reduce competition. Skeptics of the prevalence of character displacement often cite lack of evidence of competition. The present article uses a simple model to examine whether competition is needed for character displacement and whet...

This paper studies the usefulness of the P-model in the analysis of the behaviour of prices in Iranian economy. The P-model is based on the Quantity of Theory of Money. This model believes that the price level tends to move towards the equilibrium price level. The model uses price gap to forecast inflation, if the equilibrium price is greater than the current price, there is a tendency for the ...

A model system inspired by recent experiments on the dynamics of a folded protein under the influence of a sinusoidal force is investigated and found to replicate many of the response characteristics of such a system. The essence of the model is a strongly overdamped oscillator described by a harmonic restoring force for small displacements that reversibly yields to stress under sufficiently la...

In this paper, an electrothermal shape memory alloy helical spring actuator constructed from with copper-cored enameled wire is presented and fabricated. Based on the shear constitutive model of a alloy, Thermo equilibrium equation geometrical establish thermomechanical theoretical alloys under different scenarios. The behaviors were verified by numerical simulation experimental tests, properti...

in this paper, the effects of carbon nanotube (cnt) orientation and aggregation on the static behavior of functionally graded nanocomposite cylinders reinforced by cnts are investigated based on a mesh-free method. the used nanocomposites are made of the straight cnts that are embedded in an isotropic polymer as matrix. the straight cnts are oriented, randomly or aligned or local aggregated int...

A new approach is proposed to evaluate the non-limit active earth pressure in c–? soil based on horizontal slices method and limit equilibrium method, which takes into account arching effect, displacement, mobilized friction angle, tension cracks, shear stress of layer. The accuracy was demonstrated by comparing experimental results other theoretical methods. comparison showed that appropriate ...

using the quarterly data of 1990:1 to 2008:1 and in a general equilibrium approach, we investigate the long run equilibrium path of the equilibrium interest rate as well as the potential output. we implement a structural reduced form of a general equilibrium model consistent with iran’s economy and estimate the unobservable variables by employing the kalman filtering technique. a exponential ut...

Based on digital images of a tested sample, taken at different stages of loading, displacement fields are measured by using digital image correlation. The technique used here directly provides continuous displacement fields decomposed onto finite elements. From the latter, the equilibrium gap method allows one to estimate a scalar damage field over the same region of interest. Last, under the a...