OBJECTIVE The aim of this study was to determine the effects of light intensity and type of light unit (quartztungsten-halogen [QTH] or light-emitting diode [LED]) on the hardening of various resin cements and a resin composite restorative. METHODS Disk specimens were prepared from 4 dual-cured resin cements (Variolink II, Calibra, Nexus 2 and RelyX ARC). Two QTH light-curing units (Visilux 2...

objective: shear bond strength is an important property inherent to the durability of tooth-colored restorative materials namely composite resins. it has been years that halogen light sources have been used for polymerization of composite resins. in recent years light emitting diodes (led) have been introduced for this purpose. with respect to their longer bulb life, needless of a filter and no...

We prove that if q 5 is an integer, then every qth power of an integer contains at least 5 nonzero digits in its binary expansion. This is a particular instance of one of a collection of rather more general results, whose proofs follow from a combination of refined lower bounds for linear forms in Archimedean and non-Archimedean logarithms with various local arguments.

Correlation inequalities are presented for functionals of a ferromagnetic Potts model with external field, using the random-cluster representation. These results extend earlier inequalities of Ganikhodjaev–Razak and Schonmann, and yield also GKS-type inequalities when the spin-space is taken as the set of qth roots of unity.

The Thomas model is the most common equation to describe dynamics of fixed-bed adsorption columns. However, its parameters’ validity strongly depends on region breakthrough curve considered for data fitting. A rigorous analysis based different error functions was carried out determine accuracy both linear and non-linear forms model. proved be more robust less susceptible experimental error, wit...