Harmonic Excitation of an Unconstrained Saturated Particle Bed
Past research on the flow of concentrated cohensinless mixtures have historically emphasized steady or quasi-steady motions while dynamic effects have received little attention in comparison....
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)...
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...
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...
The Microstructure of Hardened Cement Paste and Concrete
Concrete is a composite material created from a mixture of a binder (hardened portland cement paste) and a filler (fine and coarse aggregates). Like any other composite material the physical...
The Morphology and Dynamics of Natural and Laboratory Grain Flows
Artificially generated sand flows that display considerable similarity with field examples on eolian dunes allow documentation of the relationships between grainflow scales and the characteristics...
Computer Simulation of Granular Flows
Discrete-particle computer simulations using up to 15,000 identical spheres reproduce particle-scale information obtained from high-speed motion picture observations of disperse, collision-dominated...
Discrete Mechanics of Sediment Transport
Usually a granular medium is being represented by a continuous approximation in which the degrees of freedom of individual grains are averaged away in favor of a partial differential equation...
Computer Simulation of Dry Layered Granular Flow Down an Incline Composed of Grains
Experiments show that gravity-driven dry granular flows are essentially layered for smooth spheres. This paper describes layer-to-layer interaction in the flow. Assuming two-dimensional...
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