the aisi 316 l stainless steel (ss) specimens were exposed to passivation surface through two different processes including; holding in 40-vol% hno3 at temperature of 60 ºc for 30 min and 15-vol%h2so4 at ambient temperature for 1 hour. the corrosion behavior of specimens was evaluated in physiological solutions by electrochemical in vitro tests through linear and tafel polarization tests. cycli...

The liquefaction resistance of soil can be evaluated using laboratory tests such as cyclic simple shear, cyclic triaxial, cyclic torsional shear as well as field methods like Standard Penetration Test (SPT), Cone Penetration Test (CPT) and Shear Wave Velocity (Vs). In this regard, this study attempts to compare the results of the SPT based on the simplified procedure proposed by Seed and Idriss...

NiTi instruments have a high risk of separation due to torsional or flexural fatigue (cyclic fatigue). Chemomechanical preparation, cleaning procedures, chemical disinfection and sterilization cause the corrosion of endodontic instruments that may weaken the fracture resistance of the instruments. Objective To assess the effects of NaOCl immersion and autoclave sterilization on the cyclic fatig...

Emerging evidence shows that cyclic hypoxia exists in most solid cancers. It is believed that under cyclic hypoxic conditions cancer cells exhibit more malignant biological behaviors than under chronic hypoxic conditions. In this review, we provide a collection of evidence showing the molecular mechanisms by which cyclic hypoxia induces aggressiveness, malignant progression, and therapeutic res...

Aim: In vitro study evaluation of the cyclic fatigue resistance of reciprocating and rotary single-file system [Wave One Gold (WOG), Reciproc, Hyflex electrical discharge machining (EDM) file systems] utilizing cyclic fatigue testing device. Materials and methods: Three nickel–titanium rotary systems (Hyflex EDM size #25, 0.06 taper and Reciproc and WOG size #25, 0.06 taper) were used in this s...

INTRODUCTION In recent years, with the advances in counterfeiting methods, counterfeit products have reached the dental market. The purpose of this study was to compare the cyclic fatigue resistance of original and counterfeit rotary root canal instruments. MATERIALS AND METHODS The cyclic fatigue of original and counterfeit ProTaper F2 endodontic instruments was tested (n = 20) in 3 mm radiu...

chromate conversion coating is applied on aluminum 6061. the optimum conditions for chromate bath composition and immersion time are also obtained for standard requirements provision such as corrosion resistance in salt spray test, electrical resistance and coating quality. the applied coatings are electrochemically tested in sea and distilled water. according to tafel and cyclic polarization c...

OBJECTIVES To investigate the effects of cyclic antibiotic selection pressure on resistance in a simple mathematical model. METHODS The model assumed that resistance in microbial ecologies changes slowly with changing selection pressure, at a rate proportional to the difference between the current resistance level and the resistance level that would be in equilibrium with current selection pr...