Bonding strength of a carbon nanofiber array to its substrate

2006 ◽  
Vol 21 (11) ◽  
pp. 2922-2926 ◽  
Author(s):  
Yi Zhang ◽  
Ephraim Suhir ◽  
Yuan Xu ◽  
Claire Gu
Keyword(s):  
Bonding Strength ◽  
Carbon Nanofiber ◽  
Copper Substrate ◽  
Applied Force ◽  
Stress Model ◽  
Shearing Stress ◽  
Shearing Force ◽  
Interface Failure ◽  
Interfacial Shearing Stress

The bonding strength of a carbon nanofiber array (CNFA) grown on a copper substrate is evaluated based on the measured shearing force-at-failure and the developed analytical stress model that enables one to determine the magnitude and the distribution of the interfacial shearing stress causing the measured (given) shearing force. The experiment is conducted using specially designed test specimens. A table version of the Instron tester is used to measure the applied force and the corresponding displacement in shear. The maximum predicted shear-off stress is about 300 psi (0.211 kgf/m2), and was determined, based on the developed stress model, as a product of the measured 5 kgf/m force at the interface failure and the computed parameter k = 0.0422 m–1 of the interfacial shearing stress.

Finite-Element Analysis of a Measuring Model for FeAlCrBSiNb Coating Bonding Strength of Revolution Body

2014 ◽  
Vol 577 ◽  
pp. 722-725
Author(s):  
Jia Ying Zhang ◽  
Gang Zhao ◽  
Ye Wang Sun ◽  
Jun Wei Yang ◽  
Huai Bin Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Bonding Strength ◽  
Bonding Interface ◽  
Shearing Stress ◽  
Measuring Process ◽  
Element Analysis

The stress distribution of the coating interface in measuring bonding strength of revolution body coating was emulated. The stress curves of coating bonding interface were obtained. The abscission characteristics of coating were analyzed. It showed that Stress concentration occurred in the symmetric centre of the coating bonding interface. The coating peeled off from the symmetric centre to both sides of the sample interface in the measuring process. Avoiding shearing stress was a method to promote the measuring test of bonding strength of revolution body coating.

The viscosity of a suspension of spheres

1960 ◽  
Vol 7 (2) ◽  
pp. 230-236 ◽  
Author(s):  
A. D. Maude
Keyword(s):  
Shear Flow ◽  
The Other ◽  
Shearing Stress ◽  
Shearing Force ◽  
Velocity Change ◽  
Perturbation Field ◽  
Plane Normal ◽  
Perturbation Velocity ◽  
The Mean

It is shown that in Stokes's flow the perturbation field, due to the addition of one more sphere to a shear flow of a fluid containing a number of non-interacting spheres, has the property that the total additional shearing force, acting on any plane normal to the direction of velocity change, is zero. However, the perturbation velocity, integrated over such a plane, takes a constant value, positive if the plane lies on one side of the sphere and negative if it lies on the other side. It follows that the effect of all the spheres is not to alter the shearing stress at all, but to reduce the mean shear by a factor 1 – 2·5c, where c is the concentration. This suggests that Einstein's viscosity law should be altered to η = η0/(1 – 2·5c) when c is not small.

scholarly journals Effects of Er:YAG laser pre-treatment on dentin structure and bonding strength of primary teeth: An in vitro study

2020 ◽  
Author(s):  
Jun hui WANG ◽  
Kuan YANG ◽  
Bai ze ZHANG ◽  
Zhi fei ZHOU ◽  
Zi rui WANG ◽  
...  
Keyword(s):  
Shear Strength ◽  
Surface Treatment ◽  
Bonding Strength ◽  
Primary Teeth ◽  
Er:Yag Laser ◽  
Testing Machine ◽  
Acid Etching ◽  
Control Group ◽  
Interface Failure ◽  
Pre Treatment

Abstract Background: To investigate the effects of Er:YAG laser pre-treatment on the dentin structure and shear bond strength of primary teeth.Methods: Dentin specimens were prepared using freshly extracted intact primary molars and divided randomly into four groups based on the surface treatment applied. The control and etchant groups received no treatment and conventional acid etching treatment, respectively, while the energy and frequency groups received laser surface treatment with variable energy (50-300 mJ) and frequency (5-30 Hz) parameters. The morphology was observed using scanning electron microscopy. The surface-treated dentin slices were bonded to resin tablets, followed by thermocycle treatment. The shear strength was determined using a universal testing machine and de-bonded surfaces were observed using a stereomicroscope.Results: SEM observation showed that the surface morphology of the dentin slices changed after etching as well as after Er:YAG laser pre-treatment with different energy and frequency values. The dentin tubules opened within a specific energy (50-200 mJ) and frequency (5-20 Hz) range. Beyond this range, the intertubular dentin showed cracks and structural disintegration. Shear strength tests showed no significant changes after acid etching. The shear strength increased significantly (P<0.05) after Er:YAG laser pre-treatment compared with that of the control group. The shear strength increased within the same energy (50-200 mJ) and frequency (5-20 Hz) range as the tubule opening, but not significantly (P>0.05). The most common mode of interface failure was adhesive (interface) failure, followed by mixed and resin cohesive failure.Conclusions: Pre-treatment using Er:YAG laser opens the dentinal tubules without the formation of a smear layer and improves the bonding strength between the primary teeth dentin and the resin composites.

scholarly journals Laser-Milled Microslits Improve the Bonding Strength of Acrylic Resin to Zirconia Ceramics

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 817
Author(s):  
Saiji Shimoe ◽  
Tzu-Yu Peng ◽  
Yuki Wakabayashi ◽  
Hiroto Takenaka ◽  
Shogo Iwaguro ◽  
...  
Keyword(s):  
Bond Strength ◽  
Bonding Strength ◽  
Failure Modes ◽  
Acrylic Resin ◽  
Thermal Cycles ◽  
Air Abrasion ◽  
Zirconia Ceramics ◽  
Interface Failure ◽  
Bonding Durability ◽  
Strength And Durability

Heightened aesthetic considerations in modern dentistry have generated increased interest in metal-free “zirconia-supported dentures.” The lifespan of the denture is largely determined by the strength of adhesion between zirconia and the acrylic resin. Thus, the effect on shear bond strength (SBS) was investigated by using an acrylic resin on two types of zirconia ceramics with differently sized microslits. Micromechanical reticular retention was created on the zirconia surface as the novel treatment (microslits (MS)), and air-abrasion was used as the control (CON). All samples were primed prior to acrylic resin polymerization. After the resin was cured, the SBS was tested. The obtained data were analyzed by using multivariate analysis of variance(α = 0.05). After the SBS test, the interface failure modes were observed by scanning electron microscopy. The MS exhibited significantly higher bond strength after thermal cycles (p < 0.05) than the CON. Nevertheless, statistically comparisons resulted in no significant effect of the differently sized microslits on SBS (p > 0.05). Additionally, MS (before thermal cycles: 34.8 ± 3.6 to 35.7 ± 4.0 MPa; after thermal cycles: 26.9 ± 3.1 to 32.6 ± 3.3 MPa) demonstrated greater SBS and bonding durability than that of CON (before thermal cycles: 17.3 ± 4.7 to 17.9 ± 5.8 MPa; after thermal cycles: 1.0 ± 0.3 to 1.7 ± 1.1 MPa), confirming that the micromechanical retention with laser-milled microslits was effective at enhancing the bonding strength and durability of the acrylic resin and zirconia. Polycrystalline zirconia-based ceramics are a newly accessible material for improving removable prosthodontic treatment, as the bond strength with acrylic resin can be greatly enhanced by laser milling.

scholarly journals Effects of Er:YAG laser pre-treatment on dentin structure and bonding strength of primary teeth: An in vitro study

2020 ◽  
Author(s):  
Jun hui WANG ◽  
Kuan YANG ◽  
Bai ze ZHANG ◽  
Zhi fei ZHOU ◽  
Zi rui WANG ◽  
...  
Keyword(s):  
Shear Strength ◽  
Surface Treatment ◽  
Bonding Strength ◽  
Primary Teeth ◽  
Er:Yag Laser ◽  
Testing Machine ◽  
Acid Etching ◽  
Control Group ◽  
Interface Failure ◽  
Pre Treatment

Abstract Background: To investigate the effects of Er:YAG laser pre-treatment on the dentin structure and shear bond strength of primary teeth. Methods: Dentin specimens were prepared using freshly extracted intact primary molars and divided randomly into four groups based on the surface treatment applied. The control and etchant groups received no treatment and conventional acid etching treatment, respectively, while the energy and frequency groups received laser surface treatment with variable energy and frequency parameters. The morphology was observed using scanning electron microscopy. The surface-treated dentin slices were bonded to resin tablets, followed by thermocycle treatment. The shear strengths were determined with a universal testing machine and de-bonded surfaces were observed with a stereomicroscope. Results: SEM observation showed that the surface morphology of the dentin slices changed after etching as well as after Er:YAG laser pre-treatment with different energy and frequency values. The dentin tubules opened within a specific energy (50-200 mJ) and frequency (5-20 Hz) range. Beyond this range, the intertubular dentin showed cracks and structural disintegration. Shear strength tests showed no significant change after acid etching. The shear strength increased significantly (P<0.05) after Er:YAG laser pre-treatment compared with that of the control group. The shear strength increased within the same energy (50-200 mJ) and frequency (5-20 Hz) range as the tubule opening, but not significantly (P>0.05). The most common mode of interface failure was adhesive (interface) failure, followed by mixed and resin cohesive failure. Conclusions: Er:YAG laser pre-treatment may improve the bonding strength between the dentin and the resin in primary teeth.

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