Full and Half-Wavelength Ultrasonic Percussive Drills

Half empty or half full?

The Application of Ultrasonic Vibration Drills in Traumatology

The dynamics of ultrasonic vibration drills having the common source of rotational and reciprocal movement of the driven element has been examined. The method, the mathematical model and the specific software for the calculation of the dynamic characteristics of the drills have been developed, with regard to the power limitation of the source, namely the rod ultrasonic vibrating system. The loa...

The prediction of penetration rate for percussive drills from indirect tests using artificial neural networks

pits, quarries, and on construction sites. The prediction of the penetration rate of drilling machines is very important for cost estimation and planning of rock excavation projects. Many researchers have investigated percussive drilling theoretically or experimentally and correlated the penetration rate with various rock properties. Protodyakonov (1962) developed drop tests and described the c...

Half full or half empty VATS?

Cardiothoracic Surgeons of Great Britain and Ireland. Tom Treasure is responsible to the society for the collection and collation of these data and has a mandate from the society’s annual general meeting of its members to disseminate information based on the data. Contributors: AS, TT, and JvdM were responsible for study concept and design. TT and AS were responsible for acquisition of the data...

Synaptic Vesicles: Half Full or Half Empty?

The regulation of quantal size through pre- rather than postsynaptic mechanisms has recently received considerable attention as a potential mechanism for plasticity. Vesicular transporters catalyze the filling of synaptic vesicles with transmitter and are thus potential substrates for such presynaptic regulation. In this issue of Neuron, Prado et al. pursue this line of investigation and show t...