Newton’s Scholium on Time, Space, Place and Motion

In the Scholium to the Definitions at the beginning of the Principia, Newton distinguishes absolute time, space, place, and motion from their relative counterparts. He argues that they are indeed ontologically distinct, in that the absolute quantity cannot be reduced to some particular category of the relative, as Descartes had attempted by defining absolute motion to be relative motion with respect to immediately ambient bodies. Newton’s rotating bucket experiment, rather than attempting to show that absolute motion exists, is one of five arguments from the properties, causes, and effects of motion. These arguments attempt to show that no such program can succeed, and thus that true motion can be adequately analyzed only by invoking immovable places, that is, the parts of absolute space.

Optimization Design Study of Loader Working Mechanism Based on MATLAB Complex Method

The paper makes an analysis on the working device of loader, which plays an important role in the performance and economic benefit of the overall unit. The paper tries to develop the mathematical model of a loader working device, apply complex method taking the maximum breakout force of cylinder of rotating bucket as well as maximum lifting force of boom cylinder as the objective function and finally realize the optimization design of its design based on MATLAB software, probing into finding a efficient solution for the technical problems existing in the working device design and manufacturing.

Flow Analysis of Melted Urea in a Perforated Rotating Bucket

A comprehensive study of the internal flow field for the prilling application in a perforated rotating bucket has been carried out. Computational Fluid Dynamics (CFD) is used to investigate the flow field of urea melt inside the perforated rotating bucket. The bucket is mounted at the top of the prilling tower. In prilling process, urea melt is sprayed by the perforated rotating bucket to produce the urea droplets, which falls down due to gravity. These drops fall down through a cooling medium and solidify into prills. The velocity field in the bucket is very important to study, as it has great effect on the heat and mass transfer performance in prilling process. ANSYS 14.0 CFD package is used to simulate and Design Modeler and Catia V5 are used for geometrical model of the perforated prilling bucket. Velocity distribution on different planes are obtained and discussed.

Flow dynamics of the free surface flow in the rotating buckets of a Pelton turbine

The relative flow in the rotating buckets of a Pelton turbine was calculated with respect to the influences of centrifugal, Coriolis, and impact forces. Based on the assumption of frictionless flows, the so-called invariance equation was presented, which enables the changeable flow velocity in a rotating bucket to be calculated. The introduced jet layer method relying on the invariance equation significantly simplifies the computation of the entire jet expansion in the rotating bucket. For purely radial flows, contributions of centrifugal, Coriolis, and impact forces to the power exchange and the corresponding effectiveness relations were quantified. In general, the centrifugal force only performs the negligible work, if compared with the effectiveness of the Coriolis and the impact forces. Various calculation examples were presented to show the flow development and the effectiveness of all active forces in the rotating bucket and to explain the application of the invariance equation. The results presented in the article for frictionless flows can be applied as the reference for further computational and experimental investigations with respect to the flow friction effects on the hydraulic efficiency of a Pelton turbine.