published_or_final_version / Industrial Engineering / Master / Master of Philosophy

Review of the literature clearly illustrated the need for more information on journal bearings operating in the transition vortex regime. Especially in the light of recent information indicating that many real applications may be operating in this region and to date most consideration has been given to fully turbulent studies. Accordingly, an experimental test rig was designed to measure torque and both circumferential and axial pressure profiles. The test bearing was circular and of central circumferential supply groove design. LID ratio was 0.25 for each land and a clearance ratio of 0.00307 used to conform with "real" modelling of high speed bearings. Lubricant inlet and outlet temperature were measured (with Rem based on the latter) together with shaft speed and displacement. Three lubricants were used, Tellus 22, Tellus RIO and water to allow a Reynolds number range of 30 - 10, 000 to be covered, and thus encompassing lamina_r, transition and turbulent flow regimes. Low Reynolds number results agreed well with laminar theory and transition from laminar to vortex flow was observed to occur around the speed predicted by Taylor. In the transition region, inertial effects were found to be very small but were taken into consideration for all comparisons between theory and experiment. Existing super laminar theories were in poor agreement with experiment. An empirical theory based on friction factor results was developed including inertia and led to much improved estimates of circumferential pressure distribution. The best agreement being observed in the mid transition region were a "hump" in the friction factor v's Reynolds number results had been measured. Due to the method of measuring pressure profiles interesting observations are reported on cavitation phenomena.

Many changes have been taking place in Oregon's agriculture. Average size of farms has increased. The trend is toward fewer but larger, highly mechanized farms, leading to changed demand for farm machinery and consequently changes in farm machinery firms to meet the changing demands of farmers. In general, the research question of interest was: "What are the most effective and efficient ways farm machinery firms might adjust to the changing demands of farmers for used farm machinery and related products and services. The specific purposes of this study were to 1) evaluate farmers' and dealers' attitudes and preferences relative to guarantees on used equipment, farm service centers and information services, 2) to evaluate inconsistencies between farmers and dealer attitudes and preferences, and 3) to evaluate which of selected farm, farmer, dealer, and dealership characteristics may or may not be related to respective attitudes and preferences of farmers and dealers. Farm machinery dealers in Oregon, Washington and Western Idaho were sent questionnaires. Questionnaires were also sent to a sample of all Oregon farmers. The relationships of interest were tested for significance via a computerized contingency analysis. The farmers' attitudes and preferences suggest strongly that gross sales of used equipment could be increased if machinery dealers would provide guarantees more acceptable to farmers. Apparently, smaller farmers in particular might be induced to purchase more used equipment if guarantees were more acceptable to them. Farmers in general indicated a preference for used equipment guarantees that cover all breakdowns for a longer period, with larger farmers preferring guarantees covering only major breakdowns. Farmers were divided as to whether used equipment guarantees should cover all or half the labor costs of repairing breakdowns, but felt more strongly that guarantees should cover all parts costs. They were also divided as to whether the guarantee period should be 30, 60 or 90 days. Dealers, however, strongly preferred guarantees covering 30 days and 1/2 the labor and parts costs. Farmers preferred to have more acceptable guarantees rather than lower prices, which suggests a willingness to pay some price for the added services. Farmers indicated farm service centers would be more convenient for them. Smaller farmers were more inclined than larger farmers to prefer doing business with a farm service center. The study indicates about 2/5 of a service centers' customers would be within 25 miles and 4/5 within 50 miles. Farmers much preferred to have service centers house competing suppliers of products and services, and decidedly felt the service center should be located outside the city limits of towns. Farmers were divided as to whether the service center should be operated as a farmers' cooperative, as independent business or as a combination of both. Three fourths or more of the farmers preferred that farm service centers carry the following products, listed in order of priority, highest priority first: Farm machinery; fertilizer; chemicals; hardware and power tools; tires, batteries and accessories; and feed, followed closely by a preference for a blacksmith and machine shop, and irrigation supplies. Farmers indicated a substantial preference for machinery related information/educational services, with primary preference for material relating to machinery and equipment maintenance, minor engine repairs, equipment leasing and engine tune-ups. The information/ educational services appealed particularly to larger farmers, farmers planning larger machinery expenditures and younger farmers. / Graduation date: 1971

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