Graduation date: 1992

Characterization of semi-permeable films promotes the systematic selection of membranes and process design. When acquiring the diffusive and sorption properties of gas transport in non-porous membranes, the time lag method is considered the conventional method of characterization. The time lag method involves monitoring the transient accumulation of species due to permeation on a fixed volume present in a downstream reservoir. In the thesis at hand, an alternative approach to the time lag technique is proposed, termed as the short cut method. The short cut method appoints the use of a two reservoir system, where the species decay in the upstream face of the membrane is monitored, in combination with the accumulation on the downstream end. The early and short time determination of membrane properties is done by monitoring the inflow and outflow flux profiles, including their respective analytical formulas. The newly proposed method was revealed to have estimated the properties at 1/10 the required time it takes for the classical time lag method, which also includes a better abidance to the required boundary conditions. A novel design of the upstream reservoir, consisting of a reference and working volume, is revealed, which includes instructional use, and the mechanics involved with its operation. Transient pressure decay profiles are successfully obtained when the reference and working volumes consisted of only tubing. However when tanks were included in the volumes, large errors in the decay were observed, in particular due to a non-instantaneous equilibration of the pressure during the start up. This hypothesis was further re-enforced by examining different upstream tank-based configurations. iii In the end, a validated numerical model was constructed for the purpose of simulating the two reservoir gas permeation system. A modified form of the finite differences scheme is utilized, in order to account for a concentration-dependent diffusivity of penetrants within the membrane. Permeation behavior in a composite membrane system was disclosed, which provided a new perspective in analyzing the errors associated with the practical aspect of the system.

A methodology to measure in-plane permeability of fibrous media using a transient one dimensional air flow is developed. The method, based on the measurement of gas pressure at the boundaries throughout the transient flow, is convenient, clean and fast, avoids usage of a gas flow meter and offers a way to study the gas transport within fibrous media. The gas transport through fibrous porous media is described by several models to comply with different flow regimes. The permeability, only depending on the fibrous structure, is determined by inverse method, fitting the simulation results to the experimental data obtained using rising or dropping pressure methods. The results of viscous permeability Kv of Glass/Carbon Twill Woven fabrics (viscous permeability Kv ranging from 10-11 to 10-10 m2) measured using gas match well the permeability measured with liquid compression and injection techniques from previous works. The deviation from Darcy's law caused by gas sliding effect on low permeability Carbon Uni-Directional fabrics (Kv from 10-14 to 10-12 m2) is analyzed and a related parameter of fabric material shows a dependence in permeability, with a similar trend as the Klinkenberg sliding parameter in soils and rocks.The experimental errors due to dimensions, thermal effect, pressure variation, sample handling, and trapped gas at boundaries are analyzed. It comes out that the sensitivities of pressure sensors and trapped gas volumes at the boundaries have the most important effects. A design for 2D measurement using gas to obtain 2D permeability tensor in one single test is proposed to avoid the issues of trapped gas at boundaries. Simulated experiments show that the measurements based on pressure measured at three proposed locations could provide robust and accurate results for fabrics of anisotropic permeability ratios (K1/K2) ranging from 0.1 to 10, with various principal permeability direction orientations.

Porous asphalt pavements offer an alternative technology for stormwater management. A porous asphalt pavement differs from traditional asphalt pavement designs in that the structure permits fluids to pass freely through it, reducing or controlling the amount of run-off from the surrounding area. By allowing precipitation and run-off to flow through the structure, this pavement type functions as an additional stormwater management technique. The overall benefits of porous asphalt pavements may include both environmental and safety benefits including improved stormwater management, improved skid resistance, reduction of spray to drivers and pedestrians, as well as a potential for noise reduction. With increasing environmental awareness and an evolving paradigm shift in stormwater management techniques, this research aims to provide guidance for Canadian engineers, contractors, and government agencies on the design of porous asphalt pavement structures. One of the keys to the success of this pavement type is in the design of the asphalt mix. The air void percentage, which is ultimately related to the effectiveness of the pavement to adequately control the runoff, is a critical component of the mix. However, special consideration is required in order to obtain higher air void percentages while maintaining strength and durability within a cold climate. The objectives of this study were to evaluate several laboratory porous asphalt mix designs for durability and strength in cold climate conditions. The porous asphalt mixes consisted of a porous asphalt Superpave mix design method whereby the asphalt binder type was varied. Performance testing of the porous asphalt including draindown susceptibility, moisture-induced damage susceptibility, dynamic modulus, and permeability testing were completed. Based on the preliminary laboratory results, an optimal porous asphalt mix was recommended for use in a Canadian climate. Initial design guidelines for porous asphalt were provided based on preliminary findings and hydrological analysis.

Papers are coated in order to improve the properties of the surface, to improve printability and to include new functionalities like barriers properties. Typical coating formulation contains a high number of components, some are made from minerals and others are manufactured from petroleum. The barrier properties of today's paper based packages are plastics and/or aluminum             foil. Environmentally friendly substitutie of these nonrenewable materials are needed.  Nanocellulose is a promising material                 and of a growing interest as an alternative to petroleum-based materials, since nanocellulose films/coatings have been shown to have excellent mechanical and barrier properties.   This project aimed to evaluate nanocellulose in combination with minerals in paper coatings. The project had two approaches. One was to evaluate the barrier properties of MFC coatings with mineral included. The second part was about coatings for           printing matters, and evaluation of the possibility to replace petroleum-based binders in the coating color with MFC. Barrier properties were evaluated by measuring the air permeability of the coatings. The properties of the coating affecting the         printability in offset printing examined was the surface energy, the gloss, the roughness of the coatings, the strength and the offset ink setting.   Carboxymethylated nanocellulose formed denser films and had superior barrier properties compared with enzymatically pretreated nanocellulose. Adding of minerals did not affect the barrier properties of the MFC coatings to a significant extent.         Therefore, minerals cannot be added to enhance the barrier but it can be added to reduce the cost of the coating process without losing any barrier properties.                                 The print quality depends on how the ink interacts with the coating. These coatings did have a relatively high surface energy, which is preferable for printing with waterborne ink. It was also shown that the absorption abilities increased when the amount of MFC was increased. However, offset printing demands high surface strength and addition of MFC in the coating color                     drastically decreased the strength. This means that the coatings produced in this work are not strong enough and thereby not           suitable for offset printing. However other printing technologies put lower demand on surface strength and are still possible.

Chitosan membrane has found applications in biomedical, wastewater treatment, and petrochemical fields that involve the use of silver ions (Ag+). However, mobility of Ag+ in chitosan membranes has seldom been studied. In this study, transport properties of Ag+ in chitosan membranes are studied in-depth, to determine diffusivity coefficient, permeability coefficient, and sorption uptake of Ag+ in chitosan. All parameters are evaluated based on the influence of feed concentration, membrane thickness and operating temperature. The diffusivity is determined from the time lag obtained from transient diffusion experiments. The permeability is determined from the steady state of permeation experimentally. The diffusivity and corresponding permeability coefficients of Ag+ in chitosan range from to 2.0 10-7 (cm2/s) and from 6.6 10-8 to 2.0 10-7 {mol m/[m2 s (mol/L)]}, respectively, over the conditions tested. Temperature dependencies of these two parameters are found to follow the Arrhenius relationship. Sorption uptake of the silver salt in chitosan correlates well with the Langmuir isotherm. Also determined from the sorption tests are degree of membrane swelling at different concentrations. This information allows diffusivity coefficients to be determined from the steady state permeation rate. These values of diffusivity are compared with that obtained using the time lag method.

Porous asphalt pavements offer an alternative technology for stormwater management. A porous asphalt pavement differs from traditional asphalt pavement designs in that the structure permits fluids to pass freely through it, reducing or controlling the amount of run-off from the surrounding area. By allowing precipitation and run-off to flow through the structure, this pavement type functions as an additional stormwater management technique. The overall benefits of porous asphalt pavements may include both environmental and safety benefits including improved stormwater management, improved skid resistance, reduction of spray to drivers and pedestrians, as well as a potential for noise reduction. With increasing environmental awareness and an evolving paradigm shift in stormwater management techniques, this research aims to provide guidance for Canadian engineers, contractors, and government agencies on the design of porous asphalt pavement structures. One of the keys to the success of this pavement type is in the design of the asphalt mix. The air void percentage, which is ultimately related to the effectiveness of the pavement to adequately control the runoff, is a critical component of the mix. However, special consideration is required in order to obtain higher air void percentages while maintaining strength and durability within a cold climate. The objectives of this study were to evaluate several laboratory porous asphalt mix designs for durability and strength in cold climate conditions. The porous asphalt mixes consisted of a porous asphalt Superpave mix design method whereby the asphalt binder type was varied. Performance testing of the porous asphalt including draindown susceptibility, moisture-induced damage susceptibility, dynamic modulus, and permeability testing were completed. Based on the preliminary laboratory results, an optimal porous asphalt mix was recommended for use in a Canadian climate. Initial design guidelines for porous asphalt were provided based on preliminary findings and hydrological analysis.

Many geoenvironmental applications make use of granular drainage layers. Design guidelines for these drains recommend a granular soil that provides for filtration of the adjacent base soil. Filtration criteria have been developed through laboratory studies in which fine soils under a concentrated gradient of water are protected from erosion by a filter soil. The primary objective in these studies has been the geotechnical stability of earth-fill structures, while drainage was a secondary consideration. Granular drainage layers have therefore been constructed using fine sand. The subsequent migration of fine soil into these drains has resulted in significant loss in permeability. The main research objective was to develop design criteria for granular drains to be used for long term operation in environmental applications. The secondary objective was to investigate the relationships between grain size distribution of drain materials and clogging by fines. This was done through a laboratory study where changes in permeability were measured in granular soils infiltrated with fines. Lastly, the effect of salinity on fines deposition was also investigated. The hypothesis of the current study is that coarser granular drains minimize the impact of clogging and provides a better alternative to traditional drain designs for long term environmental applications. The laboratory study was performed with three granular drainage soils: a French Drain sand designed using the traditional filter design method, a coarser uniform sand, and a coarser graded sand with approximately 40% gravel sized particles. Three fine soils were used to infiltrate the drainage soils; however, their particle size distributions were not significantly different from one another. The results indicate that the permeability of all three drainage soils could be reduced by approximately one order of magnitude with continuous flow of a high concentration of fines (5 g/L). The permeabilities of the sands were reduced to a lesser extent with a lower concentration of fines. Permeabilities of the graded soils decreased more slowly with a lower concentration of fines, when considering pore volumes of flow. However, the rate of permeability decrease was ultimately influenced by the amount of fines delivered to the sample. A lower concentration of fines did not significantly slow the rate of permeability reduction in the uniform sand. All three sands retained a similar mass of fines (samples were split and fines content measured following each test). Salinity in the pore water did not significantly affect deposition, likely due to the fact that the fines contained a small amount of clay sized particles. When considering that all three drainage soils became clogged with fines during the tests, the coarse soils maintained a relatively high permeability due to the fact that their pre-test permeabilities were high. This information, along with the results from the literature review, has led to the development of recommended new design criteria for granular drains to be used for long-term geoenvironmental applications. Test results from an earlier study found that dispersive soils subject to high gradients can be successfully protected by a filter coarser than the coarse graded soil used in the current study. It therefore follows that a granular soil intended for groundwater collection applications can be made to be coarser than the current accepted practice. A proposed granular drain design band is presented in the current study.

Molecular dynamics simulations were used to study the permeation of four different solutesthrough different cholesterol containing lipid bilayers. In all bilayers the limiting permeationbarrier shifted towards the hydrophobic core, as the cholesterol concentration was increased.Cholesterols reducing effect on the permeation rate was observed, but under certainconditions results indicating an increased permeation rate with increasing cholesterolconcentration were also obtained.

This study investigate water uptake in six different species of hardwood in tangential and radial section. Alder (Alnus glutinosa) and beech (Fagus sylvatika) represent semi-diffuse-porous hardwoods. Aspen (Popolus tremula) and birch (Betula pubescens) represent diffuse-porous group; oak (Quercus robur) and ash (Fraxinus excelsior) the ring-porous hardwoods. Spruce (Picea abies) was used as a reference sample. Significantly higher water uptake was observed in the diffuse-porous and the semi-diffuse-porous group. Water uptake varied among the species, nevertheless tangential section was more permeable in general. Any impact of density or annual rings width on water uptake was observed. Correlation between ratio of earlywood and latewood and water uptake in dependence on hardwood group was found out. Ring-porous species had low rate of earlywood and low water uptake, whereas diffuse-porous and semi-diffuse-porous hardwoods had high rate of earlywood and high water uptake. Relation between water uptake and microstructure of wood was observed.