Harvest weed seed controls (HWSC) destroy weed seeds that are retained by the plant at crop harvest, which would typically be spread by the harvester along with other field residues. HWSC exploits coincidental maturity between crops and weeds, so an experiment was designed to collect weed seeds as they shatter throughout the growing season and through a simulated harvest delay. This experiment monitored four economically important broadleaf species and two grass species in a soybean (Glycine max (L.) Merr.) field. Results indicated that broadleaf species shattered seed at rates accelerating through the growing season, while grass species shattered more seed early in the growing season. Field experiments in organic and conventional winter wheat (Triticum aestivum L.) fields infested with Italian ryegrass (Lolium perenne L. ssp. multiflorum (Lam.) Husnot) compared two HWSC techniques to grower-standard weed management programs in each system, including both no-till and full-till standard treatments in the conventional system. Italian ryegrass populations were monitored, and wheat yield was measured both before and after HWSC application. In both organic and conventional cropping systems, HWSC treatments did not provide better Italian ryegrass control than the grower-standard treatments. The conventional program including tillage boosted Italian ryegrass populations. These results suggest that HWSC treatments did not enhance Italian ryegrass control compared to grower-standard practices in either the organic or conventional systems. Additionally, broadleaf weeds may retain enough seeds to be viable targets for HWSC. Incorporating best practices, such as a timely crop harvest, is key for understanding and optimizing HWSC. / Master of Science

MSCAGR ( Plant Production) / Department of Plant Production / See the attached abstract below

Brittle bodies differ from the rigid ones in the possibility of shattering into small pieces according to the laws of physics. The brittle body simulation therefore uses principles of a general rigid body simulation and requires solutions to the other problems related to object decomposition into fragments and involving these fragments of the original object in the simulation. Description and evaluation of the possible solutions to this problem and a proposal with a reference implementation of such simulation are the goals of this thesis.

<p> Inland degradational trends of coastal dolomite pavements (on the Amabel formation near Tobermory Ontario Map 1) were examined in three wave energy settings: passive, intermediate, and active shores. </p> <p>Six pavement property trends were examined to determine the effect of low fetch lengths (7-10 km - Ford 83) and long shallow wave approach (Map 1) on the break-up of passive coastal pavements (south-west Bear's Rump Island): vegetation cover , grike dimensions, fracturing, pitting, shattering and flaking, and soil and rubble depths. </p> <p> Detailed analysis of small scale surface solution features, "karren", was undertaken at five 1 m sample grids on the intermediate average fetch 70-90 km -Grosset 85) Cyprus Lake provincial park pavements. </p> <p> / Thesis / Bachelor of Arts (BA)

Some Epidemic models with fractional derivatives were proved to be well-defined, well-posed and more accurate [34, 51, 116], compared to models with the conventional derivative. An Ebola epidemic model with non-linear transmission is fully analyzed. The model is expressed with the conventional time derivative with a new parameter included, which happens to be fractional (that derivative is called the 􀀀derivative). We proved that the model is well-de ned and well-posed. Moreover, conditions for boundedness and dissipativity of the trajectories are established. Exploiting the generalized Routh-Hurwitz Criteria, existence and stability analysis of equilibrium points for the Ebola model are performed to show that they are strongly dependent on the non-linear transmission. In particular, conditions for existence and stability of a unique endemic equilibrium to the Ebola system are given. Numerical simulations are provided for particular expressions of the non-linear transmission, with model's parameters taking di erent values. The resulting simulations are in concordance with the usual threshold behavior. The results obtained here may be signi cant for the ght and prevention against Ebola haemorrhagic fever that has so far exterminated hundreds of families and is still a ecting many people in West-Africa and other parts of the world. The full comprehension and handling of the phenomenon of shattering, sometime happening during the process of polymer chain degradation [129, 142], remains unsolved when using the traditional evolution equations describing the degradation. This traditional model has been proved to be very hard to handle as it involves evolution of two intertwined quantities. Moreover, the explicit form of its solution is, in general, impossible to obtain. We explore the possibility of generalizing evolution equation modeling the polymer chain degradation and analyze the model with the conventional time derivative with a new parameter. We consider the general case where the breakup rate depends on the size of the chain breaking up. In the process, the alternative version of Sumudu integral transform is used to provide an explicit form of the general solution representing the evolution of polymer sizes distribution. In particular, we show that this evolution exhibits existence of complex periodic properties due to the presence of cosine and sine functions governing the solutions. Numerical simulations are performed for some particular cases and prove that the system describing the polymer chain degradation contains complex and simple harmonic poles whose e ects are given by these functions or a combination of them. This result may be crucial in the ongoing research to better handle and explain the phenomenon of shattering. Lastly, it has become a conjecture that power series like Mittag-Le er functions and their variants naturally govern solutions to most of generalized fractional evolution models such as kinetic, di usion or relaxation equations. The question is to say whether or not this is always true! Whence, three generalized evolution equations with an additional fractional parameter are solved analytically with conventional techniques. These are processes related to stationary state system, relaxation and di usion. In the analysis, we exploit the Sumudu transform to show that investigation on the stationary state system leads to results of invariability. However, unlike other models, the generalized di usion and relaxation models are proven not to be governed by Mittag-Le er functions or any of their variants, but rather by a parameterized exponential function, new in the literature, more accurate and easier to handle. Graphical representations are performed and also show how that parameter, called ; can be used to control the stationarity of such generalized models. / Mathematical Sciences / Ph. D. (Applied Mathematics)

Kraft recovery boiler smelt is shattered into small droplets by an impinging steam jet to prevent smelt-water explosions in the dissolving tank. Inadequate shattering increases the likelihood of dissolving tank explosions. While industry has not dedicated much effort to smelt shattering, the safety implications require smelt shattering to be studied in detail. An experimental set-up was constructed to simulate the shattering operation using a water-glycerine solution and air instead of smelt and steam respectively. The objective was to examine how physical properties and flow characteristics affect shattering. It was found that increasing shatter jet velocity greatly reduced droplet mean diameter. Increasing the liquid flow rate greatly increased droplet size, as expected. Shattering was not significantly affected by viscosity, unless a weak shatter jet was used on a highly viscous fluid. Increasing the proximity of the shatter jet nozzle decreased droplet size.

Kraft recovery boiler smelt is shattered into small droplets by an impinging steam jet to prevent smelt-water explosions in the dissolving tank. Inadequate shattering increases the likelihood of dissolving tank explosions. While industry has not dedicated much effort to smelt shattering, the safety implications require smelt shattering to be studied in detail. An experimental set-up was constructed to simulate the shattering operation using a water-glycerine solution and air instead of smelt and steam respectively. The objective was to examine how physical properties and flow characteristics affect shattering. It was found that increasing shatter jet velocity greatly reduced droplet mean diameter. Increasing the liquid flow rate greatly increased droplet size, as expected. Shattering was not significantly affected by viscosity, unless a weak shatter jet was used on a highly viscous fluid. Increasing the proximity of the shatter jet nozzle decreased droplet size.