• Structural Engineering and Mechanics
• /
• v.68 no.2
• /
• pp.171-182
• /
• 2018

For the first time, nonlocal damped vibration and buckling analyses of arbitrary tapered bidirectional functionally graded solid circular nano-plate (BDFGSCNP) are presented by employing modified spectral Ritz method. The energy method based on Love-Kirchhoff plate theory assumptions is applied to derive neutral equilibrium equation. The Eringen's nonlocal continuum theory is taken into account to capture small-scale effects. The characteristic equations and corresponding first mode shapes are calculated by using a novel modified basis in spectral Ritz method. The modified basis is in terms of orthogonal shifted Chebyshev polynomials of the first kind to avoid employing adhesive functions in the spectral Ritz method. The fast convergence and compatibility with various conditions are advantages of the modified spectral Ritz method. A more accurate multivariable function is used to model two-directional variations of elasticity modulus and mass density. The effects of nanoscale, in-plane pre-load, distributed dashpot, arbitrary tapering, pinned and clamped boundary conditions on natural frequencies and buckling loads are investigated. Observing an excellent agreement between results of current work and outcomes of previously published works in literature, indicates the results' accuracy in current work.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.5 s.133
• /
• pp.66-75
• /
• 2005

Soybean-based adhesives have recently been reconsidered as alternatives to petroleum-based adhesives due to the uncertainty of availability of petrochemical products and the increased demand for wood adhesives. This study was conducted to investigate the adhesive properties of alkaline phenolic soy (APS) resin for hybrid poplar flakeboard. The APS resin was formulated by crosslinking an alkaline soy flour hydrolyzate with lab-prepared PF resin in the soy hydrolyzate to PF resin weight ratios of 70/30, 60/40, and 50/50. The APS resins were used to fabricate homogeneous hybrid poplar flakeboards with different resin solid levels (5%, 7%, and 9%), press temperatures (175 and $200^{\circ}C$), and press times of 8 and 10 minutes. The IB, wet MOR, and dimensional stability properties of board improved with increasing press time, press temperature, and PF level in APS resins. Increasing press time can be used to offset poor IB strength associated with a 9% resin solid level and the excessive moisture content in the mat. The following conditions were concluded to meet the requirements of the CSA standard for exterior-grade flakeboard: a 50% PF level, a 5% resin content, a $200^{\circ}C$ press temperature, and an 8 minute press time.

• Journal of the Korean institute of surface engineering
• /
• v.44 no.6
• /
• pp.269-276
• /
• 2011

Phase evolution and tribological behavior of Cr-Mo-N multi compositional films with different interlayer were investigated. The films were deposited by hybrid PVD (Physical Vapor Deposition) system consisted of dc unbalanced magnetron (UBM) sputtering and arc ion plating (AIP) sources. A pure molybdenum (Mo) was used as sputtering target and also a pure Cr was used as AIP target to form the Cr-Mo-N films. Various growth planes were found, no textured surface, in all of the multi composition films. Maximum value of microhardness was measured in Cr-Mo-N film with Mo interlayer as 29 GPa. Composition film was mainly showed the aspect of the adhesive wear than CrN film. The friction coefficient was decreased from 0.6 for pure CrN coating to 0.35 for Cr-Mo-N film with Mo interlayer. This result may come from the formation of metal oxide tribo-layer which is known as solid lubricant during the wear test.

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.623-630
• /
• 1995

Silicone rubber-based sodium-selective membranes are developed for solid-state ion sensors. It was shown that the potetiometric performance of SR-based membranes are greatly dependent on the type of neutral carriers employed; among the three ionophores, N,N,N',N'-tetracyclohexyl-1,2-phenylenedioxydiacetamide (ETH 2120), bis[(12-crown-4)methyl]dodecylmethylmalonate (D12C4DMM) and monensin methyl ester (MME), examined, only ETH 2120 was compatible with the SR-based matrix. Addition of about 20 wt% plasticizer to the SR-based matrix provided the resulting membranes with potentiometric properties essentially equivalent to those of the corresponding PVC-based membranes. Owing to the strong adhesive strength of SR-based membranes, the CWEs coated \vith those membranes exhibited long lifetime with conventional electrode-like performance. Blending of PU into the SR matrix increased the lifetime of CWEs from two weeks to one month.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.3
• /
• pp.164-176
• /
• 2012

In the present study, rapeseed flour (RSF), which is a by-product from the production of edible oil and biodiesel extracted from rapeseed, was used to develop alternative adhesives for the production of plywood panels. To examine the effects of the enzyme on the adhesive properties and formaldehyde emission of the RSF-based adhesive resins, three enzymes, such as cellulase (CEL), pectinase (PEC) and protease (ALC), were used either separately or together. As a crosslinking agent, PF prepolymers, which were prepared with 1.5, 1.8 and 2.1 mole formaldehyde and 1 mol phenol (1.8-, 2.1- and 2.4-PF), were added into the RSF hydrolyzates. The adhesive resins formulated with CEL- or CEL-PEC-RSF hydrolyzates and 1.8-F/P PF prepolymers exhibited excellent adhesive strengths and formaldehyde emission. The tensile shear strength and formaldehyde emission of the plywood panels bonded with the formulate resins were satisfied with the minimum requirement of the KS standard for ordinary plywood panels (0.6 N/$mm^2$). In addition, formaldehyde emissions of the plywood panels approached to that of E0 specified in the KS standard (0.5 mg/${\ell}$), and even had much better than those of commercial UF glue mixes. Overall, the use of RSF-based adhesive resins for the production of plywood panels might provide durable adhesive properties and an environmentally friendly substitute for petroleum-based adhesive resins. However, further researches - the increase of solid content of RSF-based adhesives for reducing press time and the microscopic observation of plywood specimen for identifying the relationship between tensile shear strength and the penetration of adhesives into wood structure - are required to commercialize the RSF-based adhesives.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.702-705
• /
• 2005

Metallic sandwich plates with Inner dimpled shell subjected to 3-point bending have been analyzed and then optimized for minimum weight. Inner dimpled shells can be easily fabricated by press or roll with high quality precision and bonded with same material skin sheets by resistance welding or adhesive bonding process. Optimized shape of inner dimple is a hemispherical shell to minimize weight without failure, including face yielding, face buckling and inner dimple buckling. It is demonstrated that bending stiffness of sandwich plate is 2 or 3 times than solid plates with same strength

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1125-1128
• /
• 2007

The laminating technique for developing flexible liquid crystal display was demonstrated by using a thin UV curable polymer film and a plastic substrate with patterned polymer wall structure. We adopted the rigid wall structure to provide a solid mechanical support for the stable molecular alignment of liquid crystals (LCs) in the device. The cover film was prepared to have an ability of aligning LC molecules by patterning a micro-groove structure using the soft-lithographic process. These two substrates can be assembled tightly by the laminating and one-step UV irradiation process because of the adhesive nature of the used UV curable polymers. Proposed method can be used to fabricate the flexible LC display with simplicity and also be applicable for a cost-effective roll-to-roll process.

• Proceedings of the KWS Conference
• /
• 2002.10a
• /
• pp.1-14
• /
• 2002

There is a continuous development of the most common welding processes like MMA, MIG/MAG, PAW and SAW. At the same time there is a conversion from stick electrodes to solid and cored wires with an increased productivity as a result. In parallel with these changes new processes are introduced and implemented. The number of Friction Stir Welding installations is starting to grow fast Hybrid laser welding has probably made a technical break through. The Magnetic Pulse Welding process is taking off. The different mechanical joining methods; clinching and self-piercing riveting; must not be forgotten. Structural adhesive is another method to consider.

• Journal of the Korean Home Economics Association
• /
• v.37 no.2
• /
• pp.113-126
• /
• 1999

In order to investigate the detergency effect of stained cotton and PET fabric, respectively, these fabrics stained with solid soils such as carbon black, liquid paraffin, and fat and examined the detergency effect in the optimum washing condition. The evaluation of washing efficiency of washed fabrics studied by using the surface reflectance measurement before and after washing treatment. The maximum detergency effect of stained cotton and PET fabric obtained in the mixed washing liquor-bleachig agen(ml)/concentrated washig agent(g/l). To obtain the excellent detergency effect, 2-step washing treatment, pre-washing by bleaching agent only and washing by concentrated detergent, is preferred. In comparing the detergency of polyester and cotton fabric, the detergency of stained polyester fabric superior than that of stained cotton fabric because of the difference of adhesive force between soil material and fabric in preparing soled stained fabric. In this study, we also studied the degree of fabric damage by the measurement of tensile strength change. From the results of the tensile strength measurement, the damage of washed fabric before and after washing treatment was nearly changed.

• Ceramist
• /
• v.9 no.6
• /
• pp.30-36
• /
• 2006

Joining ceramics to metals has a variety of applications both in the structural and the electronics fields. One of the great benefits of the adoption of joining into the structural applications is to provide reliability to the ceramic components by backing up with metal components. In joining ceramics and metals, two key factors, i.e., establishing chemical bonding at interfaces and dissipation of thermal stress across interfaces, should be paid for attention. Many joining methods have been already established such as adhesive and mechanical joining, brazing and soldering, and solid state bonding. Each has its own benefits with some drawbacks. One can select a suitable process and materials following the requirements of the application. This report focuses on the current status of joining technology for ceramics/metal system.