introduction: the aim of this study was to evaluate the influence of different levels of external irrigation during irradiation with an erbium, chromium: yttrium-scandium-gallium-garnet (er,cr:ysgg) laser on the roughness and wear of dental tissue during scaling procedures. methods: twenty-five uniradicular bovine teeth had the proximal surfaces planed and divided into 3 regions: upper, middle ...

The aim of the present work is to determine the influence of technologically produced boron surface layers on the friction parameters in the sliding pairs under mixed friction conditions. The current boronizing processes allow obtaining surface layers of high hardness and high resistance to corrosion and wear, with low brittleness and no tendencies towards cracking However, the operation charac...

Abstract The results of combined using laser metal deposition technology with layer-by-layer heat treatment are presented and the experimental setup is described to unite remelting and/or surface hardening implementation. layers formed at stages additional alternate in material. ratio between thicknesses obtained during crystallization stage shown vary widely depending on technological paramete...

A latent hardening model based on binary junction-induced hardening can effectively describe the anisotropy measured in multiaxial tests. However, this approach still has some descriptive and predictive limitations. Recent findings show that binary junctions generated by interactions of pairs of dislocations can only induce short-term hardening effect due to the unzipping process of binary junc...

Although a laser beam with small diameter (< 1 mm) can significantly improve surface morphology, the polishing efficiency is very low, and improvement of hardness negligible. In this work, novel polishing-hardening (LPH) method integration high for treatment AISI D2 tool steel using large-size (Φ2.8 was proposed, effects hardening (LH), (LP), LPH treatments on topography microhardness were exam...

introduction: the aim of this study was to evaluate the composite surface treated by different powers of erbium-doped yttrium aluminum garnet (er:yag) laser in comparison with bur preparation via scanning electron microscope. methods: fourteen composite resin blocks with 15× 10 × 10 mm dimensions were used in this study. the samples were divided to seven groups as follow: group 1 (power: 1 w, e...

The stability of compressive residual stresses and the stability of strain hardening states are seen to have high technical importance. For a laser beam welded AlMgSiCu-alloy, results of applied stress and residual stress relaxation at elevated temperatures 100<T<150°C are presented. These experiments prove the existence of back stresses. The level of these stresses can be estimated to be in th...

Highly stressed components of modern aircraft engines, like fan and compressor blades, have to satisfy stringent requirements regarding durability and reliability. The induction of compressive residual stresses and strain hardening in the surface layer of these components has proven as a very promising method to significantly increase their fatigue resistance. The required surface layer propert...

studying gaussian beam is a method to investigate laser beam propagation and abcd matrix is a fast and simple method to simulate gaussian beam propagation in different mediums. of the abcd matrices studied so far, reflection and refraction matrices at various surfaces have attracted a lot of researches. however in previous work the incident beam and the principle axis of surface are in parallel...