The outward–pointing principal null direction of the Schwarzschild Rie-mann tensor is null hypersurface–forming. If the Schwarzschild mass spontaneously jumps across one such hypersurface then the hypersurface is the history 1 of an outgoing light–like shell. The outward– pointing principal null direction of the Kerr Riemann tensor is asymptotically (in the neighbourhood of future null infinity...

Long-range beam-beam collisions may limit the dynamic aperture and the beam lifetime in colliders. Their effect can be compensated by a current-carrying wire mounted parallel to the beam. A compensation scheme based on this principle has been proposed for the Large Hadron Collider (LHC). To demonstrate its viability, a prototype wire was installed at the CERN SPS in 2002. First successful machi...

Maxillary denture bases having three types of palatal vault shapes –shallow, medium and deep– were used in this study. The reinforced materials used were the round metal wire-diametered in 1.50 mm, semirounded metal wire -thickened 1.50×0.75 mmand the stainless steel mesh (70mmx2.5mmx2.5mm). A total of 132 acrylic denture bases were prepared with the conventional method from heat-cured acrylic ...

Human carbonic anhydrase II (HCA II), among the fastest enzymes known, catalyzes the reversible hydration of CO 2 to HCO 3 (-). The rate-limiting step of this reaction is believed to be the formation of an intramolecular water wire and transfer of a proton across the active site cavity from a zinc-bound solvent to a proton shuttling residue (His64). X-ray crystallographic studies have shown thi...

Copper wire bonding has gained popularity due to its economic advantage and superior electrical performance. However, copper is harder than gold, and replacing gold wire with copper wire introduces hardness related issues. This article reports investigations of the properties including microhardness of the copper balls bonded using /25.4-lm copper wire and different combinations of electronicfl...

This paper develops a computational method for numerical control (NC) of traveling wire electric discharge machining (EDM) operation from geometric representation of a desired cut profile in terms of its contours. Normalized arc length parameterization of the contour curves is used to represent the cut profile and a subdivision algorithm is developed together with kinematic analysis to generate...

During metallic wire drawing processes, the presence of knots and the failure to detect them can lead to long production interruptions, significant economic losses and a lower quality of final product. Consequently, there is a pressing need to develop methods for real-time detection and prevention of this fault. In this paper a sensor to prevent the formation of knots during the metallic wire d...

A 60-lm bond-pad-pitch wire-bonding process was developed using test dies with a SiO2 dielectric layer under aluminium pads, and was then fine-tuned for a low-k device using three types of gold wires with different mechanical properties. Bulk material hardness of the wires were characterised using a wire-bonding machine, the force applied and diameters of squashed free-air balls. It was found t...

Wire electrical discharge machining (WEDM) is a special form of traditional electrical discharge machining in which the electrode is a continuously moving conducting wire. The mechanism of metal removal in wire electrical discharge machining involves the complex erosion effect from electric sparks generated by a pulsating direct current power supply. The sparks generated between two closely spa...