Ratcheting behavior of steel 304L cylindrical shell under cyclic combined and axial loading are investigated in this paper, numerically. Cylindrical shells were fixed oblique at angle of 20° and normal with respect to the longitudinal direction of the shell and subjected to force-controlled cycling with non-zero mean force, which causes the accumulation of plastic deformation or ratcheting beha...

Introduction: Due to undeniable effect of surface treatment on restoration bond strength, this study was conducted to measure and compare the shear bond strength of hybrid ionomer and compomer using the three different methods of surface conditioning. Methods: In this in vitro experimental study, 72 samples were prepared from hybrid ionomer (Vitremer-3M) and compomer (Compoglass-Vivadent) re...

Selective laser melting is one of the modern methods manufacturing parts in production machine-building equipment, a special place occupied by complex technological processes used manufacture high-load units pneumatic-hydraulic system from heat-resistant alloys. The research was carried out on samples made powder material - stainless steel AISI 316L martensite class. Metallographic studies show...

: The purpose of giving space maintainer in primary dentition is to prevent the migration adjacent teeth, thus holding dental arch for succedaneous tooth erupt. Molar band fundamental component maintainer. retention surface important ensure fixed appliance therapy. Several methods have been described improve mechanical retentive surfaces bands including sandblasting, burs, etc. Sandblasting met...

the purpose of this ex- vivo study was to evaluate the fracture resistance of simulated immature teeth, obturated with gutta-percha or resilon and reinforced by either composite resin or fiber post.eighty-four human maxillary incisors were divided into seven groups (n=12). teeth in all groups were prepared until peeso #5 (1.5mm) could be passed through the apex. root ends received 4mm of mta pl...

background and aims. because of compromised angulations of implants, the abutments are sometimes prepared. the purpose of this study was to investigate the effect of removing one wall of the implant abutment on the retention of cement-retained crowns. materials and methods. four prefabricated abutments were attached to analogues and embedded in acrylic resin blocks. the first abutment was left ...

bending and compression strength of paulownia fortunie wood grown in educational and research forest located at shastkalate, gorgan were studied. paulownia trees were selected among five years old plantation. sampling spot was conducted following standard procedure. trees were cut into logs, which were then cut into 6 cm thickness wood blocks based on geographic directions. wood blocks were div...

Introduction: This study aimed to evaluate the effect of pretreatment with a neutral fluoride agent on shear bond strength (SBS) and microleakage of orthodontic brackets, and to investigate any significant relationship between SBS and microleakage. Methods: Forty intact premolars were selected and randomly divided into 2 groups. Group 1 served as the control, while group 2 underwent treatment w...