The purpose of this research was to quantify feedstock supply risk over the lifetime of an agricultural residue-based (straw and chaff) biorefinery and to determine the range of delivered prices. The Peace River region of Alberta was used as a case study for analysis, with a geographic information system utilized for data analysis. Inter-year availability of crop residues was highly variable over the 20 year period under study, which created significant differences in the delivered price of feedstock between minimum, average, and maximum availability scenarios. At the four primary study sites (Fahler, Grimshaw, Peace River, and Sexsmith), the range was from double the average availability for the maximum scenario to zero biomass available for the minimum scenario. Biomass availability is a function of grain yield, the biomass to grain ratio, the cropping frequency, and residue retention rate used to ensure future crop productivity. Using minimum, average, and maximum supply scenarios, delivered price was determined using the dynamic (time-dependent) Integrated Biomass Supply Analysis and Logistics (IBSAL) simulation model. Five biorefinery capacities, ranging from 50,000 to 500,000 tonnes of feedstock per year, were analyzed. Since no biomass was available to model in true minimum years, a simulated minimum of half the average availability was used. Delivered cost, including harvest and transportation, for the 50,000 t plant ranged from $24.01 t-1 for the maximum availability scenario at the Sexsmith site to $42.63 t-1 for the simulated minimum scenario at the Fahler site. The range for the 500,000 t plant at the Sexsmith site was $41.78 for the maximum availability and $70.98 for the simulated minimum availability. As no biomass is available (and hence the true cost is unknown) in some years, storage strategies must be implemented and alternate feedstock sources identified to supply biorefineries in low-yield years. Since feedstock cost is a large component of total operating cost of a biorefinery, feedstock supply variability and delivered cost inconsistency should be primary decision criteria for any future biorefinery projects.

Halifax Harbour is one of the world's largest natural harbours and has significant environmental and economic value. A good understanding of oceanographic processes is required for pollution control and sustainable development of the Harbour. A five-level nested-grid coastal ocean circulation model known as the Nested-grid Coastal Ocean Prediction System for Halifax Harbour (NCOPS-HFX) is used to reconstruct the three-dimensional circulation and hydrography and associated temporal and spatial variability of the Harbour. The NCOPS-HFX is driven by tides, meteorological forcing, and buoyancy forcing associated with river and sewage discharges. Model performances are assessed by comparing model results with available observations including sea level from tide gauges, CTD observations, current meter records and monthly mean climatology of temperature and salinity. Model results are also used to examine the main physical processes affecting circulation and hydrography in the Harbour. It is found that the near-surface currents in the Harbour are significantly affected by tides and wind forcing with an intense tidal jet in the Narrows and a salinity front in the upper layer of Bedford Basin. The time-mean circulation produced by the model is characterized by a typical two-layer estuarine circulation with seaward flow in the upper layer and landward flow in the lower layer. The model also reproduces reasonably well the seasonal changes of temperature and salinity in the Harbour. Dispersion and retention in the Harbour are studied based on numerical passive tracer and particle tracking experiments. The e-folding flushing time is about 40 and 90 days in the upper and entire Bedford Basin respectively, 2-5 days over the Inner and Outer Harbour, and about 1 day in the Narrows.

No description available.

No description available.

The objective of this dissertation is to extend the use of spatial predictive modelling for use by biosecurity agencies to help prevent the introductions of new and emerging invasive plants (i.e., pests). A critical review of international and national policy instruments found that they did not effectively articulate how spatial predictive modelling could be incorporated into the biosecurity toolbox. To determine how spatial predictive modelling could be extended I modelled the potential distribution of Tamarix and Lythrum salicaria in Prairie Canada using a genetic algorithm. New seasonal growth data was used to interpolate a growing degree-day’s risk surface for L. salicaria. Models were developed using suites of predictive variables as well as different data partitioning methods and evaluated using different performance measures. Expert evaluation was found to important in final model selection. The results indicated that both invasive plants have yet to reach their potential distribution in Prairie Canada. The spatial models can be used to direct risk-based surveillance efforts and to support biosecurity policy decisions. The results of this dissertation conclude that spatial predictive modelling is an informative tool that needs to be incorporated into the biosecurity toolbox. A phytosanitary standard is proposed to guide toolbox development.

One-dimensional steady flow pollutant transport models assume that the river reach modelled has a uniform cross-sectional shape which manifests as a constant average velocity in the model equations. Rarely do rivers meet this criterion. Their channels are seldom uniform in shape, but rather alternate in a quasi-periodic manner between pool and riffle sections. This bedform sequencing imparts a corresponding variation in the average cross-sectional velocity which is not accounted for in constant velocity transport models. The literature points out that the pool and riffle planform may be the reason for the sometimes poor predictions obtained from these models. This thesis confirms that the fluctuation in average cross-sectional velocity caused by the pool and riffle planform does have a marked effect on transport in rivers. The pool and riffle planform promotes an enhanced decay of a pollutant when a first order biochemical reaction is simulated. This effect becomes more pronounced as flow declines. The reason for this is that travel time in a pool and riffle channel is greater than for a uniformly shaped channel. Current one-dimensional models assume a uniform channel and therefore overestimate the velocity of a substance moving downstream. To show this an equation is developed that describes the variation in average cross-sectional velocity along a pool and riffle channel. The parameters of the equation can be easily evaluated for any river. The equation is incorporated into a mass balance analysis and a new form of the river transport model is derived. Analysis shows that the transport of a substance in a pool and riffle channel is governed by travel velocity which is different from the average cross-sectional velocity used in the traditional advection model. Replacing average velocity with travel velocity provides a simple fix for the traditional model. The new transport model is tested on the Athabasca River with excellent results. The variable velocity model successfully simulates the DO dynamics on a 550 kilometre stretch of the river. This suggests that the model has good potential for simulating pollutant transport in other rivers. Since analysis shows that the effect of the pool and riffle planform on contaminant transport is magnified at low flow levels, the model has good potential for use in determining TMDLs for contaminants, because these regulatory levels are set for low flow conditions.

The focus of this thesis is the inclusion of stochasticity into mathematical models of assembly with particular interest to the in vitro polymerisation of intermediate filaments, one of three components of the cytoskeleton. From the chemical master equation (CME), two additional models (the reaction rate equations or RREs and the two-moment approximation equations or 2MA equations) are derived. As analysis of the CME is generally intractable, we present the stochastic simulation algorithm (SSA) as a means of reproducing the most probable state of the CME at a given time. The results from the SSA are compared to simulations of both the RREs and the 2MA equations and we find that the three models are in good agreement. Further, the numerical results are compared to mean lengths and length distributions of experimental data which all models are shown to mimic. Mathematical analyses of the RREs demonstrate the conservation of mass in the system, and the unique positive equilibrium is proven to be globally asymptotically stable. Further, the 2MA equations are also shown to have conservation of mass and to possess an analogous equilibrium to the one found in the case of the RREs. In general, this study illustrates how randomness can be incorporated in polymerisation models and highlights the advantages and disadvantages of the different approaches.

In conventional finite element analysis of reinforced concrete the steel bars are normally assumed to lie along the concrete element edges and very often the bond gripping the steel to the concrete is assumed to be infinitely stiff. The first assumption makes it difficult to model all steel bars leading to the inclusion of only a few representative bars. Shear reinforcement is usually ignored. Thin concrete cover also creates difficulty by causing long thin finite elements in that region. The second assumption does not reflect the true behaviour of the system. In this research a new method for the modelling of steel in reinforced concrete by finite element analysis has been developed which allows all steel reinforcement to be included in the analysis. The method is based on modelling the steel and concrete separately, the two materials being interconnected by the bond forces between them. Thus, bond stiffness is naturally included in the analysis. Such interconnection of steel and concrete is achieved by an interface bond matrix which is derived from the relative displacements between the steel and the concrete at the steel nodes. A linear bond slip relation is assumed for the bond, and a linear stress strain relation is assumed for the concrete and the steel. The work has extended also to nonlinear bond stress-slip relation. Concrete is represented by 8-noded isoparametric quadrilateral elements, and the steel is represented by two noded bar elements. The bond is represented by springs joining each steel node to all 8-concrete nodes. The solution of the resulting system of equations is achieved in an iterative manner which converges quite rapidly, and which requires less computation than the direct solution needs. Three types of problems are analysed in two dimension to demonstrate the application of this new method. These are beam, cantilever and pullout problems. The first two, being real problems, demonstrate the ability of the method to handle complex steel arrangements, thin concrete covers and anchorage of steel, while the third problem shows the application of load to the steel rather than to the concrete. Concrete and steel deformations and stresses are calculated at their nodes. Bond stresses are given at all steel nodes. In the nonlinear bond analysis, deterioration of bond will be demonstrated in pullout and pushout tests at high loads.

No description available.

Lab‐On‐a‐Chip (LOC) or Micro Total Analysis System (μTAS) technology requires precise control of minute amounts of liquid. Moving liquids in small capillaries requires bulky expensive external pumps that defy the purpose of microfabrication. By integrating a micropump into the device, it allows the system to be transportable, reliable, energy efficient and inexpensive. Such a microsystem built on a chip has been designed to study separation by dielectrophoretic chromatography. Nanobeads were successfully separated and used separately to measure fluid velocity and study the electroosmosis effect. Cell or beads of different type can be trapped in this system. This system encompasses a solid‐state AC electroosmotic pump for the manipulation of liquid‐containing cells or molecules. AC Electroosmosis is the movement of induced charges over polarised electrodes created by a non‐uniform electric field. The charges undergo Coulomb forces and drag the fluid with their motion. This results in bulk flow over the electrodes. This micro pump is used in a LOC by fabricating the pump on two sides of a microfluidic channel. The transport of material from what can be an analyte to a cell is of critical interest. The described system in the second part of this thesis presents the advantage of having a defined number of droplets, each of which is a lab on chip. The paradigm is the droplet and therefore the vessel that carries the information. Surfaces are then the place of interaction with the vessel which carries the second aspect of this thesis. Several approaches have been investigated, in particular by enclosing the droplet between two slides in order to increase the change of contact angle under the presence of polarised electrodes. This system is known as EWOD (ElectroWetting On Dielectric). It follows the approach of modified Lippmann laws and the modification of the apparent contact angle and therefore the motion of the droplet. The lid is somewhat a problem and the possibility of using liquid dielectrophoresis to create a multitude of droplets of calibrated volume is an advantage, as it is harder to create fixed‐volume droplets with an open geometry by EWOD due to contact angle hysteresis.