Roll-Waves on a Non-Newtonian Mud Layer
This article extends the theory of roll-waves due to Dressler (1949) to a thin layer of mud modeled as a power law fluid. Roll-waves are periodic bores moving at a constant velocity down...
Erosion of Steep River Banks and Time Evolution Towards Equilibrium Channel Shape
A numerical analysis of the time evolution of straight river channels is presented. The bed and bank, material is taken to be coarse, non-cohesive and uniform in size. As a result of the...
Stability of Systems of Rigid Bodies by Bounding Theorems
The stability of systems of systems of rigid bodies subjected to conservative and dissipative forces is investigated by considering the minimization of a work function subject to the kinematic...
Nonlinear Eigensolver for Exact Vibration Analysis
Vibration analysis of structural systems is concerned with accurately predicting the free vibration modes and frequencies of the vibrating system. This analysis process involves two general...
Flow Dynamics in an End-to-End Vascular Graft Junction
A study consisting of both experimental and numerical methods was performed to determine flow dynamics in the vicinity of an end-to-end anastomosis. The experimentally determined geometries...
Numerical Simulations of Diastolic Flow Patterns in a Model Left Ventricle with Varying Degrees of Mitral Stenosis
Blood flow patterns in the left ventricle are undoubtedly influenced by the physical and mechanical state of the natural mitral valve apparatus or the geometry of an artifical valve replacement....
A Multiple Disk Centrifugal Pump as an Artifical Ventricle
A pulsatile, multiple disk, centrifugal pump has been analysed and tested for potential use as an artificial ventricle. The pump is similar to a Tesla Turbine design which consists of...
Granular Flow on a Bumpy Inclined Chute
Theoretical predictions for steady, uniform granular flows of identical, smooth, nearly elastic disks and spheres on bumpy inclined chutes are obtained. Kinetic constitutive theory is...
Pattern Formation and Time-Dependence in Flowing Sand
The authors present results for a number of experiments on flowing granular materials and a novel cellular automata model for the flow of these materials when the grains are long and thin....
Modeling the Chaotic Behavior in Simple Shear Granular Flows
Simple shear granular flows have demonstrated a variety of puzzling phenomena. Both computer simulations and physical experiments have discovered particle grouping, layering and shear...
Mechanics of Granular Materials at Very Low Effective Stress Levels
Gravity's influence on laboratory specimens of uncemented granular materials subjected to low effective stresses, makes it impossible to evaluate constitutive properties in an unambiguous...
Influence of Gas Phase Turbulence on the Transport of Particles
An interesting and perhaps unexpected flow feature characterizing the transport of a gas-solid suspension in a vertical duct is the radial nonuniformity of particles over the tube cross-section....
Structural Characterization of an Articulated-Truss Joint
A first generation space crane articulated-truss joint was statically and dynamically characterized in a configuration which approximated an operational environment. The articulated-truss...
Hydrogen Reduction of Lunar Soil and Simulants
Carbotek, Inc., and the Energy and Environmental Research Center (EERC) are cooperating on further development of the Carbotek process to produce oxygen from lunar ilmenite by hydrogen...
Transient Analysis of Flexible Space Structures
A new approach for numerical analysis of flexible space frames subjected to impact forces is presented. The method is particularly effective in the analysis of large amplitude vibration...
Structural Considerations in the Design of a Mars Mission Aerobrake
A new area of civil engineering is emerging. This area will provide structures for outposts on the moon, resource development and exploration of Space. Spacecraft traveling at very high...
On-Orbit Assembly and Refurbishment of Lunar Transfer Vehicles
Initial flights of space-based manned lunar transfer vehicles (LTV) will require some on-orbit assembly and checkout due to mass and volume limitations of the Earth-to-orbit (ETO) launcher....
Response of Space Structures Under Sudden Local Damage
Damages to space structures can come from such adverse events as impact by foreign objects, docking, drastic temperature changes, and exposure to radiation and charged particles. This...
Regolith Dynamics
Due to the differences of the gravitational accelerations of the Earth and Lunar environments, geotechnical engineering must be applied differently in the two environments. This study...
Principles of Control for Robotic Excavation
Excavation can be considered one of the most unstructured problems in the construction environment. On one hand, many technologies have been developed in the past to build shelters using...
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