The dry sliding friction and wear behaviors of TC11 titanium alloy subjected to the ultrasonic impacting and rolling process (UIRP) were studied in the present work. The microstructure of the deformation layer and the morphology of the worn surfaces were observed. The results clearly show that the wear performance of TC11 alloy after UIRP is better than that of TC11 alloy before UIRP under the ...

Gear’s normal contact stiffness played an important role in the mechanical equipment. In this paper, the M-B fractal model is modified and the contact surface coefficient is put forward to set up the fractal model, considering the influence of friction, which could be used to calculate accurately the involute arc cylindrical gears’ normal contact stiffness based on the fractal theory and Hertz ...

Introduction: The present study aimed to evaluate an experimental herbal mouthwash, as compared to sodium fluoride mouthwash on the frictional resistance and surface roughness between brackets and two rectangular archwire types. Methods: A total of 60 premolar׳s brackets engaged with 0.019×0.025 archwires made of stainless steel and nickel-titanium alloys were used in this study. The samples we...

The oxidation of stainless steels 304 and 304L during hot rolling is studied in this paper. Results show the oxide scale thickness decreases significantly with an increase of reduction, and the oxide scales of both 304 and 304L stainless steels were found more deformable than the steel substrate. Surface roughness shows a complicated transfer during the hot rolling process due to the complexity...

different construction materials with different roughness used to make circular weirs highly affect surface roughness and, in turn, flow hydraulics passing over these structures.  in the present research, numerous experiments under different hydraulic conditions were performed on a physical model to study the effects of roughness on flow hydraulics over a circular weir. the flow hydraulics incl...

This study examined the effect of cariogenic and erosive challenges (CCs and ECs, respectively) on the degradation of copper-nickel-titanium (CuNiTi) orthodontic wires. Sixty wire segments were divided into four treatment groups and exposed to CCs, ECs, artificial saliva, or dry storage (no-treatment control). CC and EC were simulated using a demineralizing solution (pH 4.3) and a citric acid s...

Modeling predictions and experimental measurements were obtained to characterize the electro-mechanical response of radio frequency (RF) microelectromechanical (MEM) switches due to variations in surface roughness and finite asperity deformations. Three-dimensional surface roughness profiles were generated, based on a Weierstrass–Mandelbrot fractal representation, to match the measured roughnes...

Kinetic friction during dry sliding along atomistic-scale Al 001 /Al 001 and -Al2O3 0001 / -Al2O3 0001 interfaces has been investigated using molecular dynamics MD with recently developed Reactive Force Fields ReaxFF . It is of interest to determine if kinetic friction variations predicted with MD follow the macroscopic-scale friction laws known as Coulomb’s law for dry sliding and Stokes’ fric...

The effect of an asymmetric distribution of asperity heights is accounted for in a recently developed scale-dependent multiasperity model of contact and friction. A Weibull distribution of asperity heights is used which allows the skew and kurtosis to be varied, but not independently of each other. The contact and friction model used includes the effects of adhesion and of scale-dependent frict...