Objectives This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-galliumgarnet (Er,Cr:YSGG) laser and the conventional acid-etching technique. Materials and Methods This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divid...

Castings of aluminum and plastics are of high importance in the industrial world. They are usually made using permanent metallic moulds for pressure die-castings and injection molding. Die-tools are usually produced from chromium maraging hot work tool steel and are heat treated to hardness between 29 and 48 HRC, 1-3 . Die life is a mayor factor of a die-casting process and it strongly affects ...

An experimental study of cracks that develop during the annealing of hydrogen-rich amorphous silica films deposited on crystalline silicon substrates shows an interesting duality of behaviour. Cracks in films deposited on cubic (001) silicon surfaces tend to form in two principal directions, cube-edge directions such as [100] or diagonal directions [110] and, while the [100] cracks are straight...

This study deals with two different aspects of scattering from the cracks. The first one is the measurement of crack resonances by local probes and the second is the effect of the roughness of the crack forces on the scattering data. Unlike the scattering measurement reported elsewhere, these measurements of crack resonances are to be performed by local probes. Two different types of probes are...

Repair welding (RW) with wire cladding is a common procedure to extend the in-service life of heavily loaded tool parts for die and mould industries 1-5 . The main advantages of repair welding are short downtime and cost efficiency compared to production of new tool part. Repair welding in general lowers the tool cost in the final part and enables higher added value to the die casting and injec...

Usually ultrasonic techniques tend to evaluate the closed cracks as smaller than the actual size. In this paper, we describe two strategic techniques for accurately evaluating the closed cracks by means of ultrasound. First, we show the advanced technique utilizing the thermal stress induced by cooling a cracked part. It is shown that a small amount of temperature decrease is effective to open ...