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Invariant mechanical properties of calcium-silicate-hydrates (C-H-S) in cement-based materials : instrumented nanoindentation and microporomechanical modeling
(Massachusetts Institute of Technology, 2006)
Random porous solids such as bone and geomaterials exhibit a multiphase composite nature, characterized by water-filled pores of nm- to m-scale diameter. The natural synthesis and operating environments of such materials ...
Hydrologic data assimilation of multi-resolution microwave radiometer and radar measurements using ensemble smoothing
(Massachusetts Institute of Technology, 2006)
Previously, the ensemble Kalman filter (EnKF) has been used to estimate soil moisture and related fluxes by merging noisy low frequency microwave observations with forecasts from a conventional though uncertain land surface ...
Understanding the role of trading in water quality management : based on U.S. experience
(Massachusetts Institute of Technology, 2006)
This research demonstrates an overview of the performance of water quality trading programs currently implemented within the U.S. The role of trading in water quality management is identified through systematical comparisons ...
Dynamic Planning and control Methodology : understanding and managing iterative error and change cycles in large-scale concurrent design and construction projects
(Massachusetts Institute of Technology, 2006)
Construction projects are uncertain and complex in nature. One of the major driving forces that may account for these characteristics is iterative cycles caused by errors and changes. Errors and changes worsen project ...
Resource allocation problems in stochastic sequential decision making
(Massachusetts Institute of Technology, 2009)
In this thesis, we study resource allocation problems that arise in the context of stochastic sequential decision making problems. The practical utility of optimal algorithms for these problems is limited due to their high ...
Momentum and scalar transport in vegetated shear flows
(Massachusetts Institute of Technology, 2005)
Environmental aquatic flows are seldom free of vegetative influence. However, the impact of submerged vegetation on the hydrodynamics and mixing processes in aquatic flows remains poorly understood. In this thesis, I present ...
Effects of water on chemomechanical instabilities in amorphous silica : nanoscale experiments and molecular simulation
(Massachusetts Institute of Technology, 2007)
We elucidate the tensile failure mechanism of amorphous silica and the effects of water on the process, combining: (a) atomic force microscope (AFM) bending tests, (b) molecular dynamics (MD) simulation and (c) molecular ...
The nanogranular origin of concrete creep : a nanoindentation investigation of microstructure and fundamental properties of calcium-silicate-hydrates
(Massachusetts Institute of Technology, 2008)
With an annual per capita consumption of one cubic meter, concrete is the most manufactured material on Earth. But concrete subject to sustained load creeps, like chewing gum, at a rate that deteriorates the durability and ...
Measuring and modeling activity and travel well-being
(Massachusetts Institute of Technology, 2009)
This thesis develops methods for the measurement of activity and travel well-being and models for linking well-being and behavior. The hypotheses underlying this research are that (1) activities are planned to maintain or ...
On triangular finite elements for general shell structures
(Massachusetts Institute of Technology, 2004)
In general, triangular elements are most efficient to discretize arbitrary shell geometries. However, in shell finite element analysis, usually quadrilateral elements are used due to their better performance. Indeed, there ...