Particle Analysis of Material Behavior?A Note on Continuum Assumptions
Continuum models of materials have dominated our approach to the analysis of material behavior. Recently a number of discrete particle methods have been proposed which offer a different...
Fracture Toughness of DMMC
The fracture toughness of discontinuous metal matrix composites (DMMC) is always less than the fracture toughness of the matrix, in the same heat treatment or annealed condition. If a...
Flow Visualization of Lid-Driven Cylindrical Cavity Flow
The lid-driven cylindrical cavity flows in the laminar region are quantitatively visualized by a new flow visualization method called the digital vector velocimetry method. Particle streak...
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...
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...
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...
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....
Mars Containers: Dust on Teflon Sealing Surfaces
As part of an evaluation of suitable hermetic seals for containers for Martian rock and soil samples, teflon (TFE) o-ring static face seals were challenged with silica gel, basalt, and...
Environmental Aspects of Lunar Helium-3 Mining
Three potential detrimental effects of lunar 3He mining have been identified; visual changes, atmospheric contamination, and solid waste disposal....
Impact Craters on Cosmic Dust: Do Damage to the Spacecraft
The discovery and study of impact crater on cosmic dust to understand the overall micrometeoroid environment and space engineering requirement are important. In this paper, we attempt...
Lunar He-3 Mining: Improvements on the Design of the UW Mark II Lunar Miner
One of the minor consituents of the solar wind which has been implanted in the lunar regolith over its several billion year history, is helium 3 (He-3), a rare isotope of helium which...
Space Habitat Contaminant Growth Models?Part II
This paper reports on the continuation of work being done at NASA's Center for Space Environmental Health (CSEH) at the University of Colorado at Boulder on contaminant growth modelling...
Mitigation of Dust Contamination During EVA Operations on the Moon and Mars
The Space Exploration initiative is charting a new course for human exploration of the Moon and Mars. Advances in EVA system have been identified as being critical for enabling long-duration...
Medical Care on the Moon
Eventually, people will return to the Moon to stay for prolonged periods of time. When they do, they will be exposed to a wide range of threats to their health including, decompression...
Regenerative Life Support Technology Challenges for the Space Exploration Initiative
Regenerative life support systems have been identified as one of the critical enabling technologies for future human exploration of space. This discipline encompasses processes and subsystems...
Mitigation of Adverse Environmental Effects on Lunar-Based Astronomical Instruments
The galactic cosmic-ray flux incident on the Moon was examined for its potential adverse impact on the performance of the large lunar telescope (LLT) proposed as a part of NASA's Space...
A Systems Approach to Water Recycling Research
Because of the cost of Earth resupply, water recycling from wastewater is a critical enabling technology for long duration space missions. The need and the fact that water quality is not...
Effective Airport Environs Planning in the 1990s
A properly coordinated environs planning effort provides a guide for development and redevelopment of the land and facilities surrounding the airport. Airport environs planning, coupled...
Minneapolis/St. Paul International (MSP) Part 150 Implementation Design Overview
In February 1991, Matropolitan Airports Commission (MAC) selected the consulting team of Aviation Planning Inc., Wyle LAboratories Inc. and the Center for Energy and the Urban Environment...
Return to search