129 Introduction The Platreef is a geological region of the Bushveld Complex—the largest source of primary platinum group metals, PGMs, in the world. PGM mineralization in the area was first reported by Dr Hans Merensky in 1924. The operation is part of the Anglo Platinum operations Potgietersrust Platinums Limited, ‘PPL’, being a wholly owned subsidiary. The operations are situated on the Nort...

An instantaneous rigid force model for prediction of cutting forces in ball-end milling of  sculptured surfaces is presented in this paper. A commercially available geometric engine is used to represent the cutting edge, cutter and updated part geometries. The cutter used in this work is an insert type ball-end mill. Intersecting an inclined plane with the cutter ball nose generates the cutting...

Neuronal circuits commonly receive simultaneous inputs from descending, ascending, and hormonal systems. Thus far, however, most such inputs have been studied individually to determine their influence on a given circuit. Here, we examine the integrated action of the hormone crustacean cardioactive peptide (CCAP) and the gastropyloric receptor (GPR) proprioceptor neuron on the biphasic gastric m...

Phasically active sensory systems commonly influence rhythmic motor activity via synaptic actions on the relevant circuit and/or motor neurons. Using the crab stomatogastric nervous system (STNS), we identified a distinct synaptic action by which an identified proprioceptor, the gastropyloric muscle stretch receptor (GPR) neuron, regulates the gastric mill (chewing) motor rhythm. Previous work ...

To ensure that these requirements were met, Chinalco and Jacobs Engineering selected ABB as a technology partner and principal supplier of the mine’s electrical and automation equipment. They awarded ABB contracts worth around $120 million to supply three gearless mill drive systems for the semi-autogenous (SAG) mill and two ball mills, a plant-wide electrical solution, and a process automation...

Background. A field study conducted by researchers found the balls used by visual impairment students at school basically used the sound by a small bell inside the ball. However, the sound emitted from the ball is very limited, the ball will sound when it is moved. This makes it difficult for students with visual impairments to find a missing ball that not emitted makes a sound. Objectives. A ...

OBJECTIVE The main purpose of this paper is to present a new method of predicting clinical performance using mechanical loading in a ball mill. METHODS A series of four experiments (two involving a hybrid composite and one each on orthodontic brackets and bands) is described in which the ball mill was used to subject specimens to mechanical fatigue. RESULTS A reproducibility study using com...

RATIONALE Isotope analysis of wood is an important tool in dendrochronology and ecophysiology. Prior to mass spectrometry analysis, wood must be homogenized, and a convenient method involves a ball mill capable of milling samples directly in sample tubes. However, sample-tube plastic can contaminate wood during milling, which could lead to biological misinterpretations. METHODS We tested poss...