Results 271 to 280 of about 190,348 (307)

Longitudinal Relaxation of Initially Straight Flexible and Stiff Polymers

Physical Review Letters, 2004
The relaxation mechanism of an initially straight flexible or stiff polymer chain of length N in a viscous solvent is studied through Brownian dynamics simulations covering a broad range of time scales. After the short-time free diffusion, the chain's longitudinal reduction R2(0)-R2 approximately Nt1/2 at early intermediate times is shown to constitute
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Initial effect of collarless stem stiffness on femoral bone strain

The Journal of Arthroplasty, 1989
Stress shielding resulting from a stiffness mismatch between bone and femoral prosthesis stems (leading to bone resorption in the proximal femur) is believed to contribute to failure in total hip arthroplasty. In this study, strains were measured under compressive femoral head loads both in the intact femur and after implanting first a collarless steel
P D, Diegel, A U, Daniels, H K, Dunn
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Sensitivity Analysis of Stiff and Non-Stiff Initial-Value Problems

1998
The solution y(t, t 0, y 0) of an initial-value problem (IVP) y(t) = f(t, y, p) with initial value y(t 0) = y 0 at a point t is a differentiable function of the initial value y 0 and the parameter vector p, provided f y and f p are continuous. The computation of the derivatives of y(t, t 0, y 0) plays an important role in the efficient numerical ...
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Stiff ODE Initial Value Problems

2011
This chapter deals with stiff initial value problems for ODEs $$\dot{x}=F(x), \,x(0)={x_0}$$ The discretization of such problems is known to involve the solution of nonlinear systems per each discretization step–in one way or the other.
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The importance of swing-phase initial conditions in stiff-knee gait

Journal of Biomechanics, 2003
The diminished knee flexion associated with stiff-knee gait, a movement abnormality commonly observed in persons with cerebral palsy, is thought to be caused by an over-active rectus femoris muscle producing an excessive knee extension moment during the swing phase of gait.
Saryn R, Goldberg, Sylvia, Ounpuu, Scott L, Delp   +2 more
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Numerical integrators for Stiff and Stiff oscillatory First Order initial value problems

Journal of the Nigerian Association of Mathematical Physics, 2008
In this paper, efforts are geared towards the numerical solution of the first order initial value problem (I.V.P) of the form Y\' = F(X,Y), X∈[ a, b] , Y(a) = Y0, where Y\' is the total derivative of Y with respect to X.. The scheme so developed for the stated equation is in the same line of thought as Fatunla (1980). It is of order 6, L-stable
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Achieving tolerance proportionality in software for stiff initial-value problems

Computing, 1989
The paper presents a basis for a uniform interpretation of the user's accuracy requirement in codes for solving stiff initial value problems. It is shown that it is possible to design the local error control strategy in a code in such a way as to achieve the tolerance proportionality. The strategy is based on a control of the local error per unit step.
Wayne H. Enright, Wendy Louise Seward
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Mechanisms Controlling the Initial Stiffness of Frozen Sand

2013
This paper presents an extensive laboratory testing program undertaken to study the influence of interface bonding and particle size, roughness, and shape on the Young's modulus of ice-saturated frozen sand in triaxial compression. The program also included the influence of particle stiffness by testing plastic beads having a much lower modulus than ...
Gregory Da Re, John T. Germaine, Charles C. Ladd   +2 more
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An Analysis of Rosenbrock Methods for Nonlinear Stiff Initial Value Problems

SIAM Journal on Numerical Analysis, 1982
The paper presents an analysis of the Rosenbrock integration method applied to a stiff system of the form \[ (1)\qquad \dot x = f(t,x,y,\varepsilon ) + \varepsilon ^{ - 1} A(t)y,\quad \dot y = g(t,x,y,\varepsilon ) + \varepsilon ^{ - 1} \mu (t)By. \] This equation possesses the following desirable model properties.
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Determining Initial Values for Stiff Systems of Ordinary Differential Equations

SIAM Journal on Numerical Analysis, 1981
We consider a stiff system of nonlinear ordinary differential equations for which we know some but not all of the initial conditions. This paper presents an algorithm which determines the unknown initial values in such a way that the solution does not have an initial transient.
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