Application of NMR to Rotating Granular Flow
Granular flow in a steadily rotating cylinder, having a large length-to-diameter ratio, is measured by nuclear Magnetic Resonance Imaging (MRI). This non-invasive technique is capable...
Postbuckling Behavior of Stiffened Composite Shell Panels
The paper summarizes the current status of an ongoing study on the postbuckling behavior of thick and moderately thick composite stiffened shells. Axially compressed moderately thick panels...
Dynamic Stability of Composite-Material Circular Cylindrical Shells with Orthogonal Stiffeners
The governing equations are formulated for general (axisymmetric or unsymmetric) vibrations of thin circular cylindrical shells of composite material and reinforced with axial (stringer)...
Variational Solutions of the Von Karman Plate Theory Based on a Mixed Formulation
A mixed formulation, involving the transverse deflection w(x,y) and the in-plane stress function F(x,y) as the unknown variables, will be used to obtain improved variational solutions...
Equivalence Between Motions with Noise-Induced Jumps and Chaos with Smale Horseshoes
For certain sets of parameters multi-stable oscillators excited by noise can exhibit irregular jumps. We consider one-degree-of-freedom near-integrable multi-stable systems whose unperturbed...
Bifurcations and Chaos in Structural Control
We study a harmonically forced oscillator with nonlinear soft spring subjected to a linear feedback control with time delay. This system can be written as a three dimensional dynamical...
Analog Electronic Simulations of a Nonlinear System
We perform electronic analog simulations of a harmonically forced Duffing oscillator. The addition of noise perturbations of sufficient intensity is shown to induce transitions between...
Routes to Chaos of a Vertically Rotating Pendulum
Each blade of a mechanical shredder may be modeled by a pendulum whose pivot rotates in a vertical circle. The transition to chaos of small periodic motion about radial lines us the driving...
Regularization Methods for Identification of Structural Damage
Generally, various non-unique solutions may be obtained from ill-conditioned equations. Several methods are available to obtain a unique (minimum energy) solution to a modified and thus...
Updating Dynamic Models and Their Associated Uncertainties for Structural Systems
The problem of updating a structural model and its associated uncertainties using dynamic test data is addressed, considering uncertainties which arise from measurement noise, modeling...
Applications of Viscoelastic Damper to Jointed Structures for Seismic Mitigation
Some structures, such as dams, are built with contraction joints that might carry some small tensile stresses. Such joints are expected to open and close during an earthquake. That will...
Anatomy of the Loma Prieta Earthquake Records of Two Steel Buildings Using MIMO System Identification
The Loma Prieta strong-motion records of a 4-story and a 47-story steel building are analyzed using system identification. A time variation study from the 4-story building records reveals...
Effect of Active Control on Closely Spaced Natural Frequencies
Current problems in structural control involve structures with closely spaced natural frequencies (M.J. Balas, 1983). The purpose of this paper is to show how control affects a structure...
A Hydraulic Study of Venous Valve Closure
The functions of the veins is to convey blood from the periphery to the heart. The distribution and transportation of blood between different parts of the body is regulated by a host of...
Systolic Anterior Motion of the Mitral Valve: In Vitro Flow Studies
Using an in-vitro approach, the goal of this study was to determine and to characterize the mechanism of systolic anterior motion of the mitral valve in obstructive hypertrophic cardiomyopathy....
Leakage Characteristics of the St. Jude Heart Valve
The requirement for anticoagulant therapy in patients implanted with mechanical heart valve prostheses is well known. A plausible explanation for this requirement is that the leakage flow...
Intra Vena Cava Balloon Pumping
An innovative prototype intravenous hollow-fiber oxygenator was developed in 1984 by B.G. Hattler. The device consisted of a microporous, hollow-fiber membrane oxygenator inserted into...
Flow Visualization Studies in the Novacor Left Ventricular Assist System
This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical...
An Evaluation Study of Modified Mohr-Coulomb and Cap Models
Two failure criteria, namely Mohr-Coulomb and cap models, are considered in this paper with some modifications. Mohr-Coulomb theory is applied to concrete after stress and strain cut-offs...
Seismic Stability Analysis of Landfill
The failure mechanism of a waste containment system is not well understood due to the complexity and the heterogeneity of the system. The recent slope failure of the Kettleman Hills waste...
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