Spelling suggestions: "subject:"porousmaterials"" "subject:"porousmaterial""
111 |
A numerical study of bacteria transport through porous media using the green element method.Ramsuroop, Suresh. January 2000 (has links)
The continued widespread contamination of the subsurface environment by microbial
pathogens and chemical wastes has resulted in an increased interest in the factors that
influence microbial transport through porous media.
In this work a numerical study is undertaken to determine the influence of various
processes that contribute to microbial transport in porous media. The evaluations were
conducted by the simulation of a typical macroscopic transport model, using a novel
numerical technique referred to as the Green Element Method (GEM). This
computational method applies the singular boundary integral theory of the Boundary
Element Method (BEM) to a discretised domain in a typical Finite Element Method
(FEM) procedure.
Three models are presented to evaluate the effects of the various parameters and
factors: a constant porosity model was formulated to verify the GEM formulation against
an analytical solution, a variable porosity linear model was developed and used for the
simulation of the transport process involving first order type clogging, and a variable
porosity nonlinear model used to evaluate effects of nonlinear type clogging. All three
models were validated by simulations in specific applications in which analytical or
deduced solutions were available. The parameters and factors evaluated included the
effects of substrate concentrations, decay rates, source concentrations (boundary
conditions), flow velocity, clogging rates, dispersivity, point and distributed sources,
and nonlinear clogging.
The results show that the trends predicted were consistent with the trends expected
from theory. The conditions that enhanced bacteria transport included high velocities,
low decay rate constants, high substrate concentrations, and low clogging rates. The
range of dispersivities investigated showed little variation in the bacteria concentration
in the longitudinal direction. Reduction in porosity resulted in retardation of the
migrating plume. Conditions that led to significant loss in porosity are high bacteria
loadings and high growth rates.
The GEM formulation showed no restrictions or limitations in solving transient linear
and transient nonlinear applications. In the nonlinear application, the Newton Raphson
algorithm was successfully used for the iterative solution procedures. In addition, the
GEM formulation easily facilitated the application of distributed and point sources in the
problem domain. / Thesis (M.Sc.Eng.)-University of Durban-Westville, 2000.
|
112 |
Radiatively induced ignition of PMMA in the presence of forced convectionKoski, Jennifer Rose 12 1900 (has links)
No description available.
|
113 |
Open-celled microcellular themoplastic foamRodeheaver, Bret Alan 08 1900 (has links)
No description available.
|
114 |
A three-dimensional mechanistic model of steam condensers using porous medium formulationAl-johani, Mohammed S. 05 1900 (has links)
No description available.
|
115 |
Experimental study of a bimolecular reaction in Poiseuille and porous media flowsRaje, Deepashree Shrikant 05 1900 (has links)
No description available.
|
116 |
Influence of vapor mass flux on simultaneous heat and mass transfer in moist porous mediaBoo, Joonhong 12 1900 (has links)
No description available.
|
117 |
Multiphase description of deforming porous media by the finite element methodArduino, Pedro 12 1900 (has links)
No description available.
|
118 |
Honeycomb tructured porous films from different polymer architectures - preparation, mechanism, analysis and post-treatmentGuerrero, Maribel Hernandaz, Chemical Sciences & Engineering, Faculty of Engineering, UNSW January 2008 (has links)
This dissertation studies and examines the process of formation of honeycomb structured porous films using various polymer architectures ranging from linear, comb, star polymers and a random copolymer. Four casting methods were designed and applied for the production of structured porous materials. The airflow casting technique, cold-stage casting technique, casting on water technique and emulsion casting technique all based in either direct water introduction to the system or indirect condensation from the environment showed to be viable options for casting of high quality porous materials. The control and study of the effect of environmental conditions towards the quality of the films has been examined through the design of a casting device and the use of the casting methods. Furthermore, the versatility of each of the architectures towards the production of honeycomb porous films has been studied. Highly regular honeycomb structured porous films were obtained from all the complex architectures namely comb polymers, star polymers and the random copolymer. However, the linear polymers did not result in regular films. Moreover the quality of the films has been assessed and mathematically quantified. In addition, some mechanistic aspects of the process of formation of honeycomb structured porous films have been addressed. Variables such as the viscosity and evaporation of polymer solutions were examined. Furthermore, the precipitation behaviour of various polymer architectures was inspected. Only the polymer architectures showing a lower viscosity and late precipitation deemed highly regular films. Finally, the modification of highly regular films from a comb polymer and a random copolymer was successfully performed for the first time by grafting a thermoresponsive polymer from the RAFT groups already present in the porous material. The non-treated films showed a typical hydrophobic behaviour for a porous membrane however after the grafting, the films exhibited hydrophilic behaviour.
|
119 |
Contaminant induced flow fffects in variably-saturated porous mediaHenry, Eric James. January 2001 (has links) (PDF)
Thesis (Ph. D - Hydrology and Water Resources) - University of Arizona. / Includes bibliographical references (leaves 177-179).
|
120 |
Reactive polymer enhanced miscible displacement in porous media /De, Debnath January 1996 (has links)
Thesis (Ph.D.) -- McMaster University, 1997. / Includes bibliographical references Also available via World Wide Web.
|
Page generated in 0.0819 seconds