• Smart Structures and Systems
• /
• v.32 no.2
• /
• pp.123-133
• /
• 2023

This paper proposes a thermography-based coating thickness estimation method for steel structures using model-agnostic meta-learning. In the proposed method, a halogen lamp generates heat energy on the coating surface of a steel structure, and the resulting heat responses are measured using an infrared (IR) camera. The measured heat responses are then analyzed using model-agnostic meta-learning to estimate the coating thickness, which is visualized throughout the inspection surface of the steel structure. Current coating thickness estimation methods rely on point measurement and their inspection area is limited to a single point, whereas the proposed method can inspect a larger area with higher accuracy. In contrast to previous ANN-based methods, which require a large amount of data for training and validation, the proposed method can estimate the coating thickness using only 10- pixel points for each material. In addition, the proposed model has broader applicability than previous methods, allowing it to be applied to various materials after meta-training. The performance of the proposed method was validated using laboratory-scale and field tests with different coating materials; the results demonstrated that the error of the proposed method was less than 5% when estimating coating thicknesses ranging from 40 to 500 ㎛.

• Tribology and Lubricants
• /
• v.36 no.6
• /
• pp.315-319
• /
• 2020

In various fields, several studies based on carbon nanotubes (CNTs) have been conducted. The results of previous studies, wherein CNT coatings have been incorporated as solid lubricants, demonstrate that the friction and wear characteristics of CNT coatings can be improved through the absorption/dispersion of the contact pressure by controlling the stiffness of the nanomesh structure comprising CNT strands. In this study, the friction and wear characteristics of the following are compared: CNT coating formed by spin coating of CNT solution, compressed CNT coating, and compressed/heated CNT coating (wherein CNT strands are squeezed through compression and/or heating). It is observed that the friction coefficient of the CNT coating having the largest number of voids between the CNT strands is significantly lower than those of the compressed CNT coating and the compressed/heated CNT coating. The wear tracks of the compressed CNT coating and the compressed/heated CNT coating indicate that some parts become torn or adhere into a lump. However, in the case of the CNT coating, a smooth wear surface is formed by rubbing. Furthermore, as the void space between the squeezed and adhered CNT strands decreases, the resistance to structural deformation increases, thereby resulting in an increased frictional force and a wear pattern that becomes torn or forms a lump. Hence, the results obtained from this study corroborate that the friction and wear characteristics of CNT coatings can be enhanced through the absorption/dispersion of the contact pressure by controlling the stiffness of the nanomesh structure of CNT coatings.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.3
• /
• pp.73-80
• /
• 2014

In this study, in order to investigate the influence of insolubilizer on the double coating structure, we carried out basic research related to the double coating formulation with four insolubilizers having various chemical types such as amino aldehyde, glyoxal and two metallic salts. It was found that although the four insolubilizers showed similar results on optical and surface properties of the coated papers, they gave different results in the printabilities of the coated papers since coating structure was significantly influenced by different reacting mechanism of the insolubilizers. Three of the insolubilizers (glyoxal, two metallic salts) showed better results than amino aldehyde type one when they were applied to top coating formulation. Metallic salts type insolubilizers showed good results in the print gloss when it was applied to top coating formulation. It was believed that amino aldehyde type insolubilizer applied top coating formulation showed good both of dry-pick and wet-pick strength.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.5
• /
• pp.80-86
• /
• 2005

High velocity oxy-fuel thermally sprayed coating of the WC-Co cermet material is a well-established process for modifying the surface properties of the structural components exposed to the corrosive and wear attacks. The hard WC phase in the coating resists to the wear while the soft metallic Co increases the adhesive and cohesive bonding properties. The coating properties deposited by the HVOF process are greatly dependent on the feedstock materials and processing parameters. The effects of the feedstock material and process coating parameters including the in-flight particle parameters and resultant coating microstructures were observed in this paper.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.4
• /
• pp.35-39
• /
• 2019

The shielding effectiveness (SE) of the EMI spray coating film was measured in a three-dimensional structure. The shielding effectiveness was measured by AST D4935 using coaxial type TEM cell. A standard sample of the cylindrical slab is fabricated to measure the shielding effectiveness using the ASTM D4935. At this time, spray coating was performed by bonding a three-dimensional structure with NAND flash memory to a standard sample. In the case of spray coating, it was uniformly coated not only on the horizontal plane but also on the vertical plane of the three-dimensional structure. As a result of measurement, shielding effectiveness of maximum 59 dB was measured in a three-dimensional structure similar to the case without three-dimensional structure. As a result, it was confirmed that the spray coating can be uniformed even in the three-dimensional structure.

• Fashion & Textile Research Journal
• /
• v.14 no.4
• /
• pp.635-640
• /
• 2012

In this study, thermoplastic urethane (TPU) coating yarns were prepared at various extruding temperatures. The fine structure and mechanical properties of resultant TPU coating yarns examined by the wide angle X-ray diffractometer (WAXD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and tensile test. TPU coating yarns (prepared at extruding temperatures at $175^{\circ}C$) were confirmed as a stable fine structure that obtained excellent tensile strength and flexibility. The C samples prepared by optimized conditions made by TPU woven floor mat. The structure of the woven mat is $4{\times}4$ basket weave and have laminated with the EVA foam to obtained final TPU woven floor mat products. The resultant TPU woven floor mat was obtained to 1.5MN of tensile strength, 22% of the elongation, and 0.2MN of tear strength. The weight loss abrasion and the resilience by the ball rebound of the TPU-woven floor mat was prior to those of the PVC subsequently, we were able to develop a woven floor mat with TPU coating yarn and produce an eco-friendly high valuable woven floor mat using an interior product.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.44 no.4
• /
• pp.16-24
• /
• 2012

To characterize the coating structure, diverse methods such as mercury intrusion, nitrogen adsorption and oil absorption methods have been developed and widely employed. These indirect techniques, however, have some limitation to explain the actual coating structure. Recently microscopic observation methods have been tried for analyzing structural characteristics of coating layers. Preparation of the undamaged cross section of a coating layer is essential for obtaining high quality image for analysis. In this study, distortion-free cross-section of the coating layer was prepared using a grinding and polishing technique. The coated paper was embedded in epoxy resin and cured. After curing the resin block it was ground with abrasive papers and then polished with diamond particle suspension and nylon cloth. Polished coating layer was sufficient enough to obtain undamaged cross sectional images with scanning electron microscope under backscattered electron image mode. In addition, the SEM images allowed distinction of the coating layer components. Also S/B latex film formed between pigment particles was visualized by osmium tetroxide staining. Pore size distribution and pore orientation were evaluated by image analysis from SEM cross-sectional images.

• Journal of the Korean Ceramic Society
• /
• v.35 no.12
• /
• pp.1257-1265
• /
• 1998

Hertzian contact tests were used to investigate the evolution of fracturedamage in the coating layer as functions of contact load and coating thickness by studying crack patterns in porcelain on glass-infiltrated alumina bilayer system conceived to simulate the crown structure of a tooth. Cone cracks initiated at the coating top surface without delamination at interface and crack propagation to substrate. Preferentially the cracks made multi-cracks at the coating top surface rather than proceeding to interface. The cracks were highly stabilized with wide ranges between the loads to initiate first cracking and to cause final failure im-plying damage-tolerant capability. Finite element modelling was used to evaluate the stress distribution. Maximum tensile stress were responsible for the cracking at the coating layer and had a profound influence on the crack pattern and fracture damage in the layered structure materials.

• Journal of the Korean Society for Heat Treatment
• /
• v.25 no.1
• /
• pp.1-5
• /
• 2012

The purpose of this study is to prepare a high strength fiberglass reinforced metal. Aluminum covering was carried out over carbon materials such as carbon fiber in order to increase their wettability to molten metals such as aluminum. A sputtering apparatus with a cylindrical target was fabricated to carry out the covering. Sputtering was caused by glow discharge between the target and the two anode plates attached to its top and bottom. As the substrate for preliminary test, a thin carbon wire was used instead of carbon fiber, and the wire was placed at the central axis of the target. Aluminium coating was formed on the whole surface of the substrate. The formation rate and structure of coating were varied by controlling the electrical potential of substrate. When the substrate was electrically isolated, coating with columnar structure was formed with a formation rate of $15{\mu}m/hr$. In case of grounded substrate, coating with amorphous structure was formed with a formation rate of $7{\mu}m/hr$.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.21 no.1
• /
• pp.78-85
• /
• 1979

In order to obtain the basic data for designing optimum flat plate solar air heaters, which can be operated with relatively low temperature for drying farm products, 8 different treatment of solar air heaters were devised and tested for their heating performances and efficiencies. The results were analised and summarized as follows. 1. The primary factors, structure of air path (C), black coating materials (A) and bottom coating methods (B) showed very high significant effect of far above 1% level. With respect to the mutual multiplying effect of secondary factors, 1% level of significance was found with coating materials and methods (AB), and 5% level of significance was found with coating materials and air path structure (AC). 2. The heating performance of the air heaters with winding air path showed about twice those with straight air path. 3. The Korean black ink which is less expensive than dim oil paint showed 3-4% better heating efficiencies as the black coating material of flat plate solar air heaters. 4. The heating efficiencies of the solar air heaters whose bottoms were not black coated were 2-3% higher than those with black coated bottoms. 5. The highest heating efficiency of solar air heater among 8 different treatment was found in the plot of Korean black ink-bottom not coated-winding air path showing 29.0-34.5%