We investigate the cause of the unusually strong semiannual variation of geomagnetic activity observed in the solar minimum years of 1954 and 1996. For 1996 we separate the contributions of the three classical modulation mechanisms (axial, equinoctial, and Russell-McPherron) to the six-month wave in the aam index and find that all three contribute about equally. This is in contrast to the longe...

A plain journal bearing is spontaneously unstable above a critical speed and loses much of its load carrying capacity when subjected to a load rotating at about half the speed of the shaft. The almost axially symmetric flow in a compressor can break down at low flow into a rotating pattern of stall cells but only the special case of a single propagating stall cell gives rise to a mechanical cou...

Introduction Since 1991, when optical coherence tomography (OCT) was first introduced as a tool for investigation in ophthalmology, OCT has become the mainstay in retinal imaging and, in some situations, has supplanted fundus fluoresce in angiography which is regarded, even today, as the gold standard for investigations in choroidal and retinal disorders. By definition, OCT represents a non-inv...

BACKGROUND Animals control the speed of motion to meet behavioral demands. Yet, the underlying neuronal mechanisms remain poorly understood. Here we show that a class of segmentally arrayed local interneurons (period-positive median segmental interneurons, or PMSIs) regulates the speed of peristaltic locomotion in Drosophila larvae. RESULTS PMSIs formed glutamatergic synapses on motor neurons...

This paper gives a brief introduction to some of the experimental facilities at Caltech being used for instruction and research. Two experiments are described: a ight control experiment using a vector thrust engine, and a low-speed, axial ow compressor rig. A common hardware and software infrastructure is used to control these experiments, allowing easy transition from instructional to research...

BACKGROUND End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed with work rate would increase organ blood flow. METHODS AND RESULTS Invasively determined CO and ...

After a brief review of varistor fundamentals, including a discussion of the infamous " speed of response " issue, the report describes several unconventional packaging implementations of varistor material (usually a flat disc between metallized electrodes), such as molded axial package, bulkhead connectors, coaxial mounting, reconstituted material, and varistor substrates with surface conducti...

By using staggering magnets, we obtain a particular type of magneting bearings, owning very interesting properties : plane gap, null axial force, and absence of coupling produced by magnetization non-homogeneities. These bearings are well adapted for low rotational speed systems, and for partially-magnetic suspensions.

A = constant b = vortex spacing C = constant to adjust turbulent spreading q = rms turbulence velocity R = mean radius T = parameter for vortex age t = time u = axial velocity v = lateral velocity w = descent speed y = spanwise coordinate, positive for port vortex z = vertical coordinate, positive pointing upwards = circulation = eddy dissipation rate = standard deviation = (effective) kinemati...

the use of bio-ethanol as an alternative diesel engine fuel is rapidly increasing. bio-ethanol is mixed with diesel fuel at different ratios and used in ci and si engines. since vibrations have direct effects on users and engine components, for this reason analysis of vibration resulting from combustion in ci engines is very important. in this study, evaluation of vibration was performed for bo...