In the paper the results of the acoustic emission (AE) based detection and characterization of stress-corrosion cracking (SCC) in stainless steel are presented. As supportive methods for AE interpretation, electrochemical noise, specimen elongation measurements, and digital imaging of the specimen surface were used. Based on the defined qualitative and quantitative time and power spectra characteristics of the AE bursts, a manual and an automatic procedure for the detection of crack related AE bursts were introduced. The results of the analysis of the crack related AE bursts indicate that the AE method is capable of detecting large scale cracks, where, apart from intergranular crack propagation, also some small ductile fractures occur. The sizes of the corresponding ductile fracture areas can be estimated based on a relative comparison of the energies of the detected AE bursts. It has also been shown that AE burst time and power spectra features can be successfully used for the automatic detection of SCC.
COBISS.SI-ID: 14050843
In natural environment, such as saliva, dental alloys are exposed to pronounced corrosion process, especially when exposed to wear during orthodontic treatment. Ni-Ti dental alloys are used in first stage of healing when movements are greater, while stainless steel (AISI 304) archwires are used in the later phases when the teeth movements are minimal. Tribocorrosion tests on two different dental wires – stainless steel and nickel titanium will be performed in conditions similar to natural, coefficient of friction and changes of open circuit potential will be monitored. Wear rate will be determined in order to describe the process during application. Different electrochemical properties will be studied in artificial saliva in the presence of fluoride and at lower pH. Metal releases in artificial saliva at different times of exposure and their increase during tribocorrosion process will be monitored by ICP-MS analysis. The study aims at obtaining the information which processes affect medical treatment or/and are potentially dangerous for patient’s health.
COBISS.SI-ID: 2147943
To assess skeletal and dentoalveolar effects of fixed functional appliances, alone or in combination with multibracket appliances (comprehensive treatment), on Class II malocclusion in pubertal and postpubertal patients. Literature survey was conducted using the Medline, SCOPUS, LILACS, and SciELO databases and The Cochrane Library, and through a manual search. The studies retrieved had to have a matched untreated control group. No restrictions were set regarding the type of fixed appliance, treatment length, or to the cephalometric analysis used. Data extraction was mostly predefined at the protocol stage by two authors. Supplementary mandibular elongation was used for the meta-analysis. Twelve articles qualified for the final analysis of which eight articles were on pubertal patients and four were on postpubertal patients. Overall supplementary total mandibular elongations as mean (95% confidence interval) were 1.95 mm (1.47 to 2.44) and 2.22 mm (1.63 to 2.82) among pubertal patients and -1.73 mm (-2.60 to -0.86) and 0.44 mm (-0.78 to 1.66) among postpubertal patients, for the functional and comprehensive treatments, respectively. For pubertal subjects, maxillary growth restraint was also reported. Nevertheless, skeletal effects alone would not account for the whole Class II correction even in pubertal subjects with dentoalveolar effects always present. Fixed functional treatment is effective in treating Class II malocclusion with skeletal effects when performed during the pubertal growth phase, very few data are available on postpubertal patients.
COBISS.SI-ID: 31524569