نتایج جستجو برای: stagnation
تعداد نتایج: 4515 فیلتر نتایج به سال:
v Abstract—The mixed convection stagnation point flow toward a vertical plate is investigated. The external flow impinges normal to the heated plate and the surface temperature is assumed to vary linearly with the distance from the stagnation point. The governing partial differential equations are transformed into a set of ordinary differential equations, which are then solved numerically usi...
Three-dimensional molecular dynamics simulations are conducted to study the nanometric cutting of germanium. The phenomena of extrusion, ploughing, and stagnation region are observed from the material flow. The uncut thickness which is defined as the depth from bottom of the tool to the stagnation region is in proportion to the undeformed chip thickness on the scale of our simulation and is alm...
Theories of economic growth hypothesize that the transition from pre-industrial stagnation to sustained growth is associated with a post-Malthusian phase in which technological progress raises income and spurs population growth while offsetting diminishing returns to labor. Evidence suggests that England was characterized by post-Malthusian dynamics preceding the Industrial Revolution. However,...
This article offers a theory of economic growth, stagnation, and demo-economic transition that originates from external effects of childbearing, health expenditure, and education under endogenous mortality. Facing a hierarchy of needs, parents always consume and want to have a family. Child quality, measured as a two-dimensional vector of child health and schooling, becomes only affordable when...
The present paper describes the analytical solutions for the steady boundary layer flow of a Jeffrey fluid over a shrinking sheet. The governing equations of motions are reduced into a set of nonlinear ordinary differential equations by using similarity transformations. Two types of problems, namely, (1) two-dimensional stagnation flow towards a shrinking sheet and (2) axisymmetric stagnation f...
We have measured the brightness of several helium free jet sources. Five converging nozzles with diameters between 0.6 and 5 m, and three tube nozzles with diameters between 2 and 10 m were studied at stagnation temperatures of 77 and 300 K and at stagnation pressures depending on nozzle size from 350 to 17000 kPa. Smaller nozzles produced higher brightness beams with values approaching 1028 s ...
Analysis of demographic catastrophes shows that, with the exception of perhaps only two critical events, they were too weak to influence the growth of human population. These results reinforce the conclusion that the concept of the Epoch of Malthusian Stagnation, the alleged first stage of growth claimed by the Demographic Transition Theory, is not supported by empirical evidence. They show tha...
A hybrid ant colony optimization technique to solve the stagnation problem in grid computing is proposed in this paper. The proposed algorithm combines the techniques from Ant Colony System and Max – Min Ant System and focused on local pheromone trail update and trail limit. The agent concept is also integrated in this proposed technique for the purpose of updating the grid resource table. This...
in our present research, we focus on the modeling of airflow related to natural disasters, such assand accumulation, with urban form studies. the objective is to find which urban form can promote sand passing andreduce as much as possible stagnation of sand in the building area (streets, alleys, etc.). the urban form design will bediscussed through the simulation of airflow by using computation...
This is a study of singular solutions of the problem of traveling gravity water waves on flows with vorticity. We show that, for a certain class of vorticity functions, a sequence of regular waves converges to an extreme wave with stagnation points at its crests. We also show that, for any vorticity function, the profile of an extreme wave must have either a corner of 120◦ or a horizontal tange...
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