scholarly journals Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer

10.3791/52931 ◽  
2015 ◽  
Author(s):  
Sheng Dong ◽  
Marcelo Dapino
Keyword(s):  
Optical Profilometer ◽  
Ultrasonic Lubrication

Rubber–Road Contact: Comparison of Physics-Based Theory and Indoor Experiments

2016 ◽  
Vol 44 (3) ◽  
pp. 150-173 ◽  
Author(s):  
Mehran Motamedi ◽  
Saied Taheri ◽  
Corina Sandu
Keyword(s):  
Rough Surface ◽  
Practical Importance ◽  
Surface Profile ◽  
Surface Characteristics ◽  
Mechanical Analysis ◽  
Friction Model ◽  
Rubber Friction ◽  
Optical Profilometer ◽  
Viscoelastic Modulus ◽  
Longitudinal Slip

ABSTRACT For tire designers, rubber friction is a topic of pronounced practical importance. Thus, development of a rubber–road contact model is of great interest. In this research, to predict the effectiveness of the tread compound in a tire as it interacts with the pavement, the physics-based multiscale rubber-friction theories developed by B. Persson and M. Klüppel were studied. The strengths of each method were identified and incorporated into a consolidated model that is more comprehensive and proficient than any single, existing, physics-based approach. In the present work, the friction coefficient was estimated for a summer tire tread compound sliding on sandpaper. The inputs to the model were the fractal properties of the rough surface and the dynamic viscoelastic modulus of rubber. The sandpaper-surface profile was measured accurately using an optical profilometer. Two-dimensional parameterization was performed using one-dimensional profile measurements. The tire tread compound was characterized via dynamic mechanical analysis. To validate the friction model, a laboratory-based, rubber-friction test that could measure the friction between a rubber sample and any arbitrary rough surface was designed and built. The apparatus consisted of a turntable, which can have the surface characteristics of choice, and a rubber wheel in contact with the turntable. The wheel speed, as well as the turntable speed, could be controlled precisely to generate the arbitrary values of longitudinal slip at which the dynamic coefficient of friction was measured. The correlation between the simulation and the experimental results was investigated.

scholarly journals Corrosion of Steel Rebars in Anoxic Environments. Part II: Pit Growth Rate and Mechanical Strength

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2547
Author(s):  
Elena Garcia ◽  
Julio Torres ◽  
Nuria Rebolledo ◽  
Raul Arrabal ◽  
Javier Sanchez
Keyword(s):  
Mechanical Strength ◽  
Chloride Content ◽  
Element Model ◽  
Offshore Structures ◽  
Anoxic Environments ◽  
Electrochemical Parameters ◽  
Cathode Area ◽  
Optical Profilometer ◽  
Set Up ◽  
Corrosion Of Steel

Reinforced concrete may corrode in anoxic environments such as offshore structures. Under such conditions the reinforcement fails to passivate completely, irrespective of chloride content, and the corrosion taking place locally induces the growth of discrete pits. This study characterised such pits and simulated their growth from experimentally determined electrochemical parameters. Pit morphology was assessed with an optical profilometer. A finite element model was developed to simulate pit growth based on electrochemical parameters for different cathode areas. The model was able to predict long-term pit growth by deformed geometry set up. Simulations showed that pit growth-related corrosion tends to maximise as cathode area declines, which lower the pitting factor. The mechanical strength developed by the passive and prestressed rebar throughout its service life was also estimated. Passive rebar strength may drop by nearly 20% over 100 years, whilst in the presence of cracking from the base of the pit steel strength may decline by over 40%.

Focus-wavelength encoded optical profilometer

1984 ◽  
Vol 49 (4) ◽  
pp. 229-233 ◽  
Author(s):  
G. Molesini ◽  
G. Pedrini ◽  
P. Poggi ◽  
F. Quercioli
Keyword(s):  
Optical Profilometer

Quality Assessment of Machined Surfaces by an Optical Profilometer

2015 ◽  
Vol 669 ◽  
pp. 443-450
Author(s):  
Jana Gerková ◽  
Ľuboslav Straka
Keyword(s):  
Quality Assessment ◽  
Surface Quality ◽  
Production System ◽  
Head Movement ◽  
Movement Speed ◽  
Technological Parameters ◽  
Cutting Head ◽  
Optical Profilometer ◽  
Machined Surfaces

Technological parameters affecting the surface quality of cutting edges in production system with the AWJ technology include cutting head movement speed. The article examines and evaluates the quality of processed surface by the AWJ technology on selected materials as related to the change of cutting head movement speed. It was discovered that the movement speed for the AWJ technology has a significant effect on the surface quality

scholarly journals Rapid, Chemical-Free Generation of Optically Scattering Structures in Poly(ethylene terephthalate) Using a CO2 Laser for Lightweight and Flexible Photovoltaic Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Simon D. Hodgson ◽  
Alice R. Gillett
Keyword(s):  
High Speed ◽  
Ethylene Terephthalate ◽  
Fold Increase ◽  
Processing Parameters ◽  
Scanning Velocity ◽  
Average Value ◽  
Free Process ◽  
Poly Ethylene Terephthalate ◽  
Optical Profilometer ◽  
Poly Ethylene

Highly light scattering structures have been generated in a poly(ethylene terephthalate) (PET) film using a CO2 laser. The haze, and in some cases the transparency, of the PET films have been improved by varying the processing parameters of the laser (namely, scanning velocity, laser output power, and spacing between processed tracks). When compared with the unprocessed PET, the haze has improved from an average value of 3.26% to a peak of 55.42%, which equates to an absolute improvement of 52.16% or a 17-fold increase. In addition to the optical properties, the surfaces have been characterised using optical microscopy and mapped with an optical profilometer. Key surface parameters that equate to the amount and structure of surface roughness and features have been analysed. The CO2 laser generates microstructures at high speed, without affecting the bulk properties of the material, and is inherently a chemical-free process making it particularly applicable for use in industry, fitting well with the high-throughput, roll to roll processes associated with the production of flexible organic photovoltaic devices.

scholarly journals Effect of Removal of Enamel on Rebonding Strength of Resin Composite to Enamel

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
L. Kilponen ◽  
L. Lassila ◽  
M. Tolvanen ◽  
J. Varrela ◽  
P. K. Vallittu
Keyword(s):  
Surface Layer ◽  
Bond Strength ◽  
Resin Composite ◽  
Optical Profilometer ◽  
Bond Strengths

Objective. To examine the effect of removing the surface layer of enamel on the rebonding strength of resin composite.Methods. Teeth in four groups (n=10) were etched, a small amount of resin composite was bonded and debonded, then specimens in three groups were ground for different lengths of time (10 s, 20 s, 30 s) to remove an increasing amount of enamel, one group was left untouched. The teeth were bonded again and the bond strengths of 1st and 2nd bonding were compared and analysed against the amount of enamel loss in different groups (7 µm (±2); 12 µm (±1); 16 µm (±3)). Specimens were examined with SEM and by noncontacting optical profilometer.Results. Although results indicated higher rebonding strength with increasing enamel removal ANOVA showed low statistical differences between the groups (p>0.05). However, values between first bonding and rebonding strengths differed significantly (p<0.05) in the group that was not ground. SEM revealed that enamel-surfaces that were ground after debonding etched well, compared to the surfaces that still contained adhesive remnants.Conclusions. Removal of small amount of enamel refreshed the surface for rebonding. Rebonding strengths without grinding the surface before bonding were lower than bond strength to intact enamel.

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