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Performance studies of externally pressurized air thrust bearings何光偉, Ho, Kwong-wai. January 1976 (has links)
published_or_final_version / Industrial Engineering / Master / Master of Philosophy
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An investigation of journal bearing behaviour in the superlaminar flow regimeMason, Peter J. January 1983 (has links)
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.
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Farm machinery merchandising : farmer and dealer preferences concerning used equipment guarantees, farm service centers and information servicesSingh, Ashok K. 23 December 1970 (has links)
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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Gear drive transmission errorsDalt, K. J. January 1980 (has links)
No description available.
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Friction and wear of ceramic fibre guidesGibbs, N. K. January 1982 (has links)
No description available.
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The use of tangential accelerometers in gear drivesEcheverria-Villagomez, Jose Salvador January 1991 (has links)
No description available.
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The simulation and control of centrifugal compressorsBoulton, C. B. January 1982 (has links)
No description available.
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Evaluation of technical systems at the design stageAguirre-Esponda, Guillermo Jose January 1992 (has links)
No description available.
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149 |
Great drive transmission errorsDaly, K. J. January 1980 (has links)
No description available.
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150 |
Calculation and measurement of the eight oil film stiffness and damping coefficients for a variable impedance hydrodynamic bearingFang, Yuefa January 1994 (has links)
No description available.
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