In aerostatic thrust bearings (ATBs), a high-pressure gas film with certain bearing capacity and stiffness is formed by passing between the moving surface static surface. Aerostatic have outstanding advantages in following aspects: high precision, speed, long service life, etc. They are widely used many fields, such as high-speed air spindles, precision machine tools, air-bearing guideways, tur...

Engineering design of computer hard disk drives is a continuously evolving area where fierce competition drives innovations in smaller, faster, higher-density designs. Different elements of the overall hard drive design involve various branches of science and engineering including materials science, electromagnetics, control theory, electrical engineering, mechanical engineering and fluid dynam...

Some tests with trapped vortices in supersonic flow-by-SUMMARY An arrangement known briefly as a vortex bearing, or trapped vortex, is described. This was devised initially with the object of improving supersonic air intakes featuring internal compression and focussing of the compression waves at the throat, Tests were made with simple rigs to check various aspects of the performance of such vo...

A new class of one-component Pd precatalysts bearing biarylphosphine ligands is described. These precatalysts are air- and thermally stable, are easily activated under normal reaction conditions at or below room temperature, and ensure the formation of the highly active monoligated Pd(0) complex necessary for oxidative addition. The use of these precatalysts as a convenient source of LPd(0) in ...

To disperse their spores to new sites, filamentous fungi and bacteria need to erect aerial filaments, which develop into fruiting bodies and spore-bearing structures. The first challenge to aerial development is breaking surface tension at an aqueous-air interface, and in both groups of microorganisms, surface-active proteins take part in the initiation of aerial morphogenesis. Comparative anal...

[reaction: see text] Palladium(II) complexes bearing a single N-heterocyclic carbene ligand serve as effective catalysts for the aerobic oxidative cyclization of alkenes with pendant sulfonamides. The use of carboxylic acid cocatalysts (AcOH and PhCO(2)H) often leads to significant improvements in catalyst stability and product yield and enables catalytic turnover to be achieved with air, rathe...

A tandem arylation/oxidation of diarylmethanes for the convenient synthesis of unsymmetrical triarylmethanols bearing different aryl and heteroaryl groups is described. A Pd(OAc)2-NiXantphos catalyst system efficiently catalyzed arylation of weakly acidic sp3-hybridized C-H bonds of diarylmethanes with aryl bromides, and the arylation products were then oxidized in situ to carbinols by simply o...

"Stately, plump Buck Mulligan came from the stairhead, bearing a bowl of lather on which a mirror and a razor lay crossed. A yellow dressing-gown, ungirdled, was sustained gently behind him by the mild morning air. . . . Solemnly he came forward and mounted the round gunrest. He faced about and blessed gravely thrice the tower, the surrounding country and the awaking mountains." Ulysses. James ...

Rotor cage faults as broken rotor bars, increased bars resistance and end-ring faults can be caused by thermal stresses, due to overload, overheating and thus mechanical stresses, magnetic stresses and dynamic stresses due to shaft torques. Environmental stresses as contamination or abrasion also contributes to the rotor cage faults. The rotor cage faults can also lead to the shaft vibration an...

A small scale, high precision co-ordinate table was developed as part of a project to solve measurement problems originating from microtechnic. Construction with a single reference surface was selected and vacuum preloaded air bearing applied in order to enable smooth motion and eliminate stick slip. Laser interferometers were applied to measure both the displacement and the angular error. The ...