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<p> High-speed machining (HSM) concepts were developed in response to productivity, quality and cost concerns. Significant advancements in controls and machining technologies have recently come together to enable the wide spread use of HSM on the plant floor. However, with the advancement of HSM technology, dynamic problems associated with modern machine-tool structures have not been fully addressed and are currently limiting performance in some applications. <p> A key aspect in the modelling of HSM processes is capturing the dynamics of the system during cutting. Machining over a wide range of rotational speeds necessitates the inclusion of many more higher modes in the system than traditionally considered. In addition many of the instruments used to assess performance such as force dynamometers are not designed to measure the cutting forces at high rotational speeds and hence the specific cutting force values being used are often times not being estimated properly. </p> <p> Thus the focus of this research is to develop a new procedure for predicting the specific cutting forces in the end-milling process for high-speed machining. An improved mechanistic model to predict the specific cutting force using acceleration data captured from the workpiece fixture was developed. The development of the new procedure has also lead to an improvement in the extraction technique used to establish the modal parameters of a machining system. This new extraction technique was found to be more flexible and easier to use than other available techniques. </p> <p> The new procedure was investigated to test the effect of choosing the number of modes of the improved modal parameters extraction technique on the estimation of the specific cutting force. The effect of filtrating the acceleration signal and the importance of including the run-out of the cutting tool in the model were also investigated. </p> <p> The new procedure was tested on different setups and with different cutting force models. Experimental validation of the proposed estimation procedure was carried out, analyzed and compared to the open literature. The new procedure was found to be more accurate while being easier to implement. </p> / Thesis / Doctor of Philosophy (PhD)

<p> This thesis provides a means of measuring the type and number of livestock on a given farm in southern Ontario using as a data base aerial photographs of medium scale. The feasibility of making such measurements is shown to be an extension of past work in the field of agricultural air photo interpretation. The methodology is presented in the form of a model. The inputs from aerial photographs are crop acreages, building type and dimensions, and silo sizes. Average yields in each study area, in combination with crop acreage gives feed available. A comparison is made between feed weight and housing space available and required feed weights and stabling facilities (taken as constants in southern Ontario) to support cattle of a given type. This comparison technique, within the model, yields an output of farm type and actual numbers of cattle. The accuracy of prediction so obtained is high and is independent of the location or attributes of the widely spaced sample areas.</p> / Thesis / Master of Arts (MA)

Cover crops (CC) can contribute to production in pastures, but the diversity of CC mixtures and defoliation frequency (DF) may alter productivity. A 2-yr experiment conducted at Raymond, MS, quantified CC × DF effects on forage mass (FM) and nutritive value of winter CC and subsequent summer hay production. Treatments were factorial combinations of 10 CC (using several species of grasses, legumes, and brassicas) and three DF (harvested every 4 or 8-wk or cut and left as mulch) in a split-plot arrangement of a randomized complete block design experiment with three replications. Generally, mixtures with legumes had greater FM and better nutritive value. Summer hay production did not respond to difference in CC composition, however, harvesting of CC reduced summer hay but increased year-long FM. These results suggest that CC when harvested can contribute to forage production with improved nutritive value and can increase year-long FM, but summer hay production can benefit when the CC is left as mulch.

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