Drilling is a widely used machining process. As the hole drilling operation progresses, a drill-bit gradually degrades until it breaks at the end of its life. Replacing a drill-bit after it is breakage can be costly in certain special applications. At the same time an early tool replacement decision may lead to lower tool life utilisation. This calls for methods that enable accurate prediction ...

The escalation hypothesis posits that predation by increasingly powerful and metabolically active carnivores has been a major driver of metazoan evolution. We test a key tenet of this hypothesis by analyzing predatory drill holes in fossil marine shells, which provide a ~500-million-year record of individual predator-prey interactions. We show that drill-hole size is a robust predictor of body ...

Scarab is a prospecting rover for lunar missions to survey resources, particularly water ice, in polar craters. It is designed for the deployment of a deep coring drill and for transport of soil analysis instruments. Its chassis can transform to stabilize the drill in contact with the ground and can also adjust to ascend and descent steep slopes of unconsolidated soil. Additional features inclu...

In this paper we investigate the dynamics and bifurcations of an oil-well drill-string model that takes the form of a neutral delay differential equation (NDDE). We consider the torsional mode of the drill-string and investigate the associated stick-slip motion. To analyse the model we develop numerical continuation routines based on Fourier-methods since existing routines based on polynomial a...

The paper describes a novel method of drilling into hard non-conductive materials by localized microwave energy (US patent 6,114,676). The Microwave Drill implementation may utilize a conventional 2.45GHz magnetron, to form a portable and relatively simple drilling tool. The drilling head consists of a coaxial guide and a near-field concentrator. The latter focuses the microwave radiation into ...

Histopathological changes occur very rapidly in the pulp when the highspeed drill, which cuts into the dentin, is used. In this investigation, we wanted to confirm possible changes occurring in the histology of healthy, vital pulp within the first thirty post-operative minutes. Six premolars extracted for orthodontic reasons in adolescents between 12 and 17 years of age were evaluated. The teet...

Cutting force sensors and neural networks have been used for the occupational safety of the drilling process. The drill conditions have been online classified into 3 categories: safe, caution, and danger. This approach can change the drill just before its failure. The inputs to neural networks include drill size, feed rate, spindle speed, and features that were extracted from drilling force mea...

Position: 39°21.9370′N, 72°41.6750′W Start hole: 1400 hr, 29 June 1997 End hole: 1500 hr, 2 July 1997 Time on hole: 73 hr (3.04 days) Seafloor (drill pipe measurement from rig floor, mbrf): 109.5 Total depth (drill pipe measurement from rig floor, mbrf): 416.3 Distance between rig floor and sea level (m): 11 Water depth (drill pipe measurement from sea level, m): 98.1 Penetration (mbsf): 306.8 ...

Information analysis often involves decomposing data into sub-groups to allow for comparison and identification of relationships. Breakdown Visualization provides a mechanism to support this analysis through user guided drill-down of polyarchical metadata. This metadata describes multiple hierarchical structures for organizing tuple aggregation and table attributes. This structure is seen in sp...