Comparative performance of squeeze film air journal bearings made of aluminium and copper

This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. Copyright @ 2012 The Authors - The article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.Two tubular squeeze film journal bearings, made from Al 2024 T3 and Cu C101, were excited by driving the single-layer piezoelectric actuators at a 75-V AC with a 75-V DC offset. The input excitation frequencies were coincident with the 13th modal frequency, at 16.32 and 12.18 kHz for the respective Al and Cu bearings, in order to produce a ‘triangular’ modal shape. The paper also provided a CFX model, used to solve the Reynolds equation and the equation of motion, to explain the squeeze film effect of an oscillating plate with pressure end leakage. The dynamic characteristics of both bearings were studied in ANSYS and then validated by experiments with respect to their squeeze film thickness and load-carrying capacity. It was observed that whilst both bearings did levitate a load when excited at mode 13, the Al bearing showed a better floating performance than Cu bearing. This is due to the fact that the Al bearing had a higher modal frequency and a greater amplitude response than the Cu bearing.This article is made available through the Brunel Open Access Publishing Fund

A Bioeconomic Analysis of the Northwestern Hawaiian Islands Lobster Fishery

Several surplus production-based bioeconomic models are applied to the Northwestern Hawaiian Islands (NWHI) commercial lobster fishery. The model which best explains the biological dynamics of the fishery is a modification of the Fox model developed by the authors. Economic costs are applied within a number of conceptual frameworks to develop the first integrated bioeconomic model of the fishery. In another development, the opportunity cost of labor based on crew share at the open access equilibrium level of fishing effort is used instead of proxy wage levels. Given the costs incurred, the fishery appears to be self-regulating in terms of long-term fishing effort for maximum sustainable yield.biological production models, fisheries economics, fisheries management, spiny lobster, slipper lobster, Environmental Economics and Policy, Resource /Energy Economics and Policy,

Instanton and Superconductivity in Supersymmetric CP(N-1) Model

The two dimensional supersymmetric CP(N-1) model has a striking similarity to the N=2 supersymmetric gauge theory in four dimensions. The BPS mass formula and the curve of the marginal stability (CMS), which exist in the four dimensional gauge theory, appears in this two dimensional CP(N-1) model. These two quntities are derived by a one-dimensional n-vector spin model in the large n limit for the N=2 case. This mapping is further investigated at the critical point. An application of the study of the BPS mass formula is proposed to the phenomena of the spin and charge separations in the Higgs phase.Comment: 6 page

rCBFand the rCMRglucose in experimental hydrocephalus measured by the double tracer method of autoradiography

開始ページ、終了ページ: 冊子体のページ付

Positron Emission Tomography in Pituitary Tumors: A Report of Three Cases

開始ページ、終了ページ: 冊子体のページ付