• The Journal of Korean Academy of Prosthodontics
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• v.44 no.6
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• pp.683-689
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• 2006

Statement of problem. Interfacial toughness is important in the mechanical property of layered dental ceramics such as core-veneered all-ceramic dental materials. The interfaces between adjacent layers must be strongly bonded to prevent delamination, however the weak interface makes delamination by the growth of lateral cracks along the interface. Purpose. The purpose of this study was to determine the effect of the reaction layer on the interfacial fracture toughness of the core/veneer structure according to the five different divesting. Materials and methods. Thirty five heat-pressed Lithia-based ceramic core bars (IPS Empress 2), $20mm{\times}3mm{\times}2mm$ were made following the five different surface divesting conditions. G1 was no dissolution or sandblasting of the interaction layer. G2 and G3 were dissolved layer with 0.2% HF in an ultrasonic unit for 15min and 30 min. G4 and G5 were dissolved layer for 15min and 30min and then same sandblasting for 60s each. We veneered bilayered ceramic bars, $20mm{\times}2.8mm{\times}3.8mm$(2mm core and 1.8mm veneer), according to the manufacturer's instruction. After polishing the specimens through $1{\mu}m$ alumina, we induced five cracks for each of five groups within the veneer close to interface under an applied indenter load of 19.6N with a Vickers microhardness indenter. Results. The results from Vickers hardness were the percentage of delamination G1:55%, G2:50%, G3:35%, G4:0% and G5:0%. SEM examination showed that the mean thickness of the reaction layer were G1 $93.5{\pm}20.6{\mu}m$, G2 $69.9{\pm}14.3{\mu}m$, G3 $59.2{\pm}20.2{\mu}m$, G4 $0.61{\pm}1.44{\mu}m$ G5 $0{\pm}0{\mu}m$. The mean interfacial delamination crack lengths were G1 $131{\pm}54.5{\mu}m$, G2 $85.2{\pm}51.3{\mu}m$, and G3 $94.9{\pm}81.8{\mu}m$. One-way ANOVA showed that there was no statistically significant difference in interfacial crack length among G1, G2 and G3(p> 0.05). Conclusion. The investment reaction layer played important role at the interfacial toughness of body ceramic bonded to Lithia-based ceramic.

• Coupled systems mechanics
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• v.9 no.5
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• pp.473-498
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• 2020

This paper presents a careful theoretical investigation into interfacial stresses in reinforced concrete foundation beam repairing with composite plate. The essential issue in the analysis of reinforced structures with composite materials is to understand the individual behaviour of each material and its interaction with the remaining ones. The present model is based on equilibrium and deformations compatibility requirements in and all parts of the repaired RC foundation beam, i.e., the reinforced concrete foundation beam, the composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions, By comparisons between the existing solutions and the present new solution enable a clear appreciation of the effects of various parameters such as the geometric characteristics and mechanical properties of the components of the repaired beam, as well as the geotechnical stresses of the soil are considered. This research is helpful for the understanding on mechanical behaviour of the interface and design of the composite-concrete hybrid structures.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.158-161
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• 1987

A Series of hydrophilic-hydrophobic copolymeric surfaces of 2-hydroxyethyl methacrylate (HEMA) and various alkyl methacrylate (RMA) have been prepared by in-situ solution copolymerization using a redox radical initiator. Contact angles of various probing fluids on the polymeric surfaces were determined in air (hydrophobic environment) and under water (hydrophilic environment). From contact angle data, the dispersive interaction contribution (${\gamma}^d_s$) and the polar contribution (${\gamma}^p_s$) to the total surface free energy (${\gamma}^d_s$) and interfacial energetic quantities (e.g., water-polymer, liquid-polymer interface, etc.) were estimated by surface and interface physicochemical theory. From the comparison of surface energetic components between hydrophobic and hydrophilic media, it is found that surface and interface energetic components of polymeric surface as a representative low-energy surface are highly dependent on environmental fluids. Also, from the correlation between interfacial energetic results and surface energetic criterion of biocompatibility, we found that HEMA/BMA, HEMA/HMA copolymer systems are in the region of biocompatibility.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.3
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• pp.380-390
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• 1993

Effect of interfacial electrical conditions on adhesion of ${\alpha}-Fe_2O_3$ particles to PET fabric and the removal of ${\alpha}-Fe_2O_3$ particles from PET fabric, were investigated as functions of pH, electrolyte and ionic strength. The ${\zeta}$ potential of PET fiber and ${\alpha}-Fe_2O_3$ particles in the electrolyte solution were measured by streaming potential and microelectrophoresis methods respectively. The potential energy of interaction between ${\alpha}-Fe_2O_3$ particles and PET fabric were calculated by using the heterocoagulation theory for a sphere-plate model. The negative ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle and PET fiber increased with pH, and then decreased certain pH and isoelectric points of ${\alpha}-Fe_2O_3$ particles and PET fiber were pH 6.5 and pH 3.5, respectively. The negative ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle and PET fiber affected by electrolytes, were relatively high with polyanion electrolytes in solutions and were low with neutral salts. However, at surfactant solution, ${\zeta}$ potential was levelled off. The influence of the ionic strength on the ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle was small but the negative ${\zeta}$ potential of PET fiber increased with the ionic strength. In the presence of anionic surfactant, the ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle and PET fiber increased regardless of solution conditions. The interaction energy between ${\alpha}-Fe_2O_3$ particle and PET fabric increased with pH. The interaction energy was relatively high with polyanion electrolytes in solution, and the influence of ionic strength on the interaction energy was small, and the effective thickness of electrical double layer increased with decreasing the ionic strength.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2696-2701
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• 2007

For the analysis of a two-phase flow, the interaction between two phases such as the interfacial momentum or heat transfer is proportional to the interfacial area. So the interfacial area concentration (IAC) is one of the most important parameters governing the behavior of each phase. This study focuses on the development of a computational fluid dynamics (CFD) code for investigating a boiling flow with a one-group IAC transport equation. It was based on the two-fluid model and governing equations were calculated by SMAC algorithm. For checking the robustness of the developed code, the experiment of a subcooled boiling in a vertical annulus channel was analyzed to validate the capability of the IAC transport equation. As the results, the developed code was confirmed to have the capability in predicting multi-dimensional phenomena of vapor generation and propagation in a subcooled boiling.

• Interaction and multiscale mechanics
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• v.1 no.4
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• pp.397-409
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• 2008

The interfacial thermal resistance of pristine and defective carbon nanotubes (CNTs) embedded in low-density polyethylene matrix is studied in this paper. Interface thermal resistance in nanosystems is one of the most important factors that lead to the large variation in thermal conductivities in literature and the novelty of this paper lies in the estimation of the interfacial thermal resistance for defective nanotubes-systems. Thermal properties of CNT nanostructures are estimated using molecular dynamics (MD) simulations and the simulations were carried out for various temperatures by rescaling the velocities of carbon atoms in the nanotube. This paper also deals with the mesoscale thermal conductivities of composite systems, using effective medium theories by considering the size effect in the form of interfacial thermal resistance and also using the conventional micromechanical methods like Hashin-Shtrikman bounds and Wakashima-Tsukamoto estimates.

• Tribology and Lubricants
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• v.17 no.1
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• pp.40-55
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• 2001

Acoustic emission(AE) signal has been widely utilized to monitor the interaction at the head/disk interface. In this work the relationship between the AE signal and the state of contact between the slider and the disk is presented. Results of the FFT(Fast Fourier Transform) analyses of the AE signal could be used to better understand the interfacial interaction. Also, it was found that wear particles affect the AE signal. Therefore, the signal can be used to monitor the wear particle presence at the interface.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.310-317
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• 1999

Acoustic emission(AE) signal has been widely utilized to monitor the interaction at the head/disk interface. In this work the relationship between the AE signal and the state of contact between the slider and the disk is presented. Results of the FFT analyses of the AE signal could be used to better understand the interfacial interaction. Also, it was found that wear particles affect the AE signal. Therefore, the signal can be used to monitor the wear particle presence at the interface.

• Journal of applied mathematics & informatics
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• v.8 no.1
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• pp.59-69
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• 2001

The paper deals with the interaction between three Griffith cracks propagating under antiplane shear stress at the interface of two dissimilar infinite elastic half-spaces. The Fourier transform technique is used to reduce the elastodynamic problem to the solution of a set of integral equations which has been solved by using the finite Hilbert transform technique and Cooke’s result. The analytical expressions for the stress intensity factors at the crack tips are obtained. Numerical values of the interaction efect have been computed for and results show that interaction effects are either shielding or amplification depending on the location of each crack with respect to other and crack tip spacing. AMS Mathematics Subject Classification : 73M25.

• Composites Research
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• v.31 no.5
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• pp.282-287
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• 2018

In this paper, we explore interfacial properties of the mineralized CNTs when they are employed as reinforcing fillers in a polymer nanocomposite using molecular dynamics (MD) simulations. Recently, several studies on mineralizing carbon nanotubes (CNTs) with an aid of nitrogen doping to CNTs have been reported. However, there is a lack of studies on the reinforcing effects of the mineralized CNTs when it is employed as a filler of nanocomposites. Silica ($SiO_2$) is used as a mineral material and poly (methyl metacrylate) (PMMA) is used as a polymer matrix. Pull-out simulations are conducted to obtain the interfacial energy and the interfacial shear stress. It was found that the silica mineralized CNTs have higher interfacial interaction with the polymer matrix. In the future, by examining various thermomechanical properties of the mineralized-CNT-filler/polymer nanocomposites, we will search for potential applications of the novel reinforcing filler.