Permeability and Dispersivity of Variable-Aperture Fracture Systems
A number of recent experiments have pointed out the need of including the effects of aperture variation within each fracture in predicting flow and transport properties of fractured media....
A Stratified Percolation Model for Saturated and Unsaturated Flow Through Natural Fractures
The geometry of the asperities of contact between the two surfaces of a fracture and of the adjacent void spaces determines fluid flow through a fracture and the mechanical deformation...
Study of Fractal Aperture Distribution and Flow in Fractures
This study examines the roughness profiles and aperture distributions of fractures and faults by using concepts from fractal geometry. Simple models of flow of fluid in rough fractures...
Geochemical Modeling: An Integrated Approach to Nuclear Waste Disposal Issues
To meet nuclear waste repository licensing requirements, the response of repository components and of the enclosing host rocks and fluids to temperature fluctuations, fluid flow, radionuclide...
Simulation of Heat Transfer in the Unsaturated Zone
It is well known that heat transfer can play an important roll in fluid flow near the emplacement site of high-level nuclear waste (K. Pruess and J.S.W. Wang, 1987). Heat transfer effects...
Combined Analytical/Numerical Approaches to Solving Fluid Flow Problems in the Unsaturated Zone at Yucca Mountain
Various analytical and numerical approaches are presented for the study of unsaturated flow processes in the vicinity of the Yucca Mountain, Nevada, the proposed site of an underground...
Modeling of Coupled Heat-Mass-Stress Effects in Geologic Media
To investigate the importance of coupled hydraulic-thermal-mechanical processes for the potential nuclear waste storage repository at the Yucca Mountain, a computer code is being developed....
Method for Determining the Fuel Contribution to the Source Term in Trasnport Casks
A comprehensive source term characterization methodology has been developed for the determination of the fuel contribution to the potentially releasable radioactivity in spent fuel shipping...
Fluid Line Deployment and Repair for Space Station
Deployment of the utility system for providing services to the NASA Space Station Freedom provides a unique challenge in design and material technology. The system must be lightweight,...
Post-MECO Propulsion System Requirements for Placement of an STS External Tank in Low Earth Orbit
This paper discusses the findings of a series of computer simulations carried out at the National Institute of Standards and Technology to investigate the requirements for powered flight...
Motion Control of Space Structures
A new area of civil engineering is emerging as we begin to establish a permanent presence in space. The new area of civil engineering is the motion control of space structures. This paper...
Effects of Initial Conditions on Large Space Structures
Effects of initial conditions of axial deformation (length) and attitude (pitch) angle have been investigated on the subsequent orbital motion, attitude (librational) motion, and axial...
Actively Controlled Optimum Structural Design
This paper deals with the investigation of the number and location of actuators and sensors on the optimum structure and control design of space structures. The optimization problem is...
Wave Propagation in Hyper-Structures
The concept of hyperelement was introduced by E. Kausel and J.M. Roesset, 1977 in connection with the derivation of the dynamic stiffness matrix for layered continuum problems involving...
The Truss-Beam and Space Technology
A method is presented herein to determine the dynamic characteristics of truss-beam systems for both planar and space structures. Results from this approach are compared with those of...
Dynamics of Composite Tubes
A displacement-based stiffness method is used to study the characteristics of dispersive wave propagation in laminated composite cylindrical tubes. It is assumed that the tube is composed...
Effect of Gravity on Dynamic Behavior of Beams
Large space structures will be needed to provide structural framework for maintaining relative positions of individual components of systems in low earth orbit. Particularly because of...
Fluid Behavior Considerations for Waste Management in Low-Gravity Environments
Design of waste recycling systems for spacecraft requires a knowledge of fluid behavior in microgravity. As gravity is reduced, phenomena usually ignored in the One-G environment of earth...
Design Considerations for a Ceramic Fabric Radiator
The design of an Advanced Ceramic Fabric (ACF) thermal management device for use in both interplanetary and near-earth space must consider several important aspects of the environment....
Identification of Aquifer Parameters in Confined Groundwater Flow
The logarithm of the aquifer properties, log transmissivity (log T) and log storativity (log S), are regarded as realizations of stochastic processes whose estimates are required. The...
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