• The Journal of Advanced Prosthodontics
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• v.8 no.6
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• pp.433-438
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• 2016

PURPOSE. The aim of this in vitro study was to evaluate the mechanical properties (bending strength and hardness) of seven different fiber reinforced composite posts, in relation to their microstructural characteristics. MATERIALS AND METHODS. Two hundred eighty posts were divided into seven groups of 40, one group for each type of post analyzed. Within each group, 15 posts were subjected to three-point bending strength test, 15 to a microhardess meter for the Knoop hardness, and 10 to Scanning Electron Microscope in order to determine the diameter of the fibers and the percentage of fibers embedded in the matrix. To compare the flexural strength in relation to the type of fiber, matrix, and the hardness of the posts, a Kruskal-Wallis H test was used. The Jonckheere-Terpstra test was used to determine if the volume percent of fibers in the post influenced the bending strength. RESULTS. The flexural strength and the hardness depended on the type of fibers that formed the post. The lower flexural strength of a post could be due to deficient bonding between the fiber and the resin matrix. CONCLUSION. According to the results, other factors, besides the microstructural characteristics, may also influence the mechanical properties of the post. The feature that has more influence on the mechanical properties of the posts is the type of fiber.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.23-35
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• 2023

The Ministry of Agriculture, Food and Rural Affairs has announced design standards for disaster-resilient greenhouses capable of resisting wind speeds with a 30-year frequency to respond to the destruction of greenhouses caused by strong winds. However, many greenhouses are still being maintained or newly installed as conventional standard facilities for the supply type. In these supply-type greenhouses, a small pile called a steel peg is used as reinforcement to resist wind-induced damage. The wind resistance of steel pegs varies depending on the soil environment and installation method. In this study, a correlation analysis was performed between the wind resistance of steel pegs installed in loam and sandy loam, using a soil hardness meter. To estimate the pull-out force of steel pegs based on soil water content and compaction, soil compaction tests and laboratory soil box and field tests were performed. The soil compaction degree was measured using a soil hardness meter that could easily confirm soil compaction. This was used to analyze the correlation between the soil compaction degree in the tests. In addition, a correlation analysis was performed between the pull-out force of steel pegs in the soil box and field. The findings of this study will be useful in predicting the pull-out force of steel pegs based on the method of steel peg installation and environmental changes.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.580-585
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• 2006

UV-thermal dually curable coating materials were prepared by the sol-gel method. Nano-sized colloidal boehmite was treated with various organo silane coupling agents. These materials could be well dispersed in various alcohols and relatively polar organic solvents such as tetrahydrofuran and acetonitrile. The coating films were prepared by a spin coating method on various substrates, which were characterized by FT-IR, Si/Al CP MAS NMR spectra, UV-Vis spectrophotometer, FE-SEM, Taber abraser, haze meter, and pencil hardness tester. The effects of molar ratio and types of silane coupling agents, curing method and ion-shower treatment were investigated. Dually curable coating method offered an optimally good quality film in both hardness and transmittance. The transparency and the hardness of the prepared films were increased with amounts of 3-(trimethoxysilyl)propylmethacrylate, and (3-glycidyloxypropyl)trimethoxysilane, respectively. The adhesion between coated layer and substrate could be enhanced by ion-shower treatment.

• Elastomers and Composites
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• v.46 no.2
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• pp.158-163
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• 2011

Rigid polyurethane foam (PUF) was synthesized with different contents of aliphatic polyester polyol, aromatic polyester polyol and aliphatic polyether polyol to know change of properties under sea water. UTM(universal testing machine), DSC(differential scanning calorimetry), hardness meter and FT-IR(Fourier transform spectroscopy) were used to study the PUF`s physical properties under sea water. Compressive strength and hardness of PUF decreased with increasing the content of aromatic polyester polyol under sea water as aging. According to the results of IR spectral analysis, reduction of urethane and urea peak was found and allophanate and biuret peak increased. Although glass transition temperature of PUF increased, mechanical properties of PUF decreased under sea water, because PUF gets brittle when crosslink density increase.

• Korean journal of food and cookery science
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• v.21 no.4 s.88
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• pp.482-489
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• 2005

Chungmiraejulpyuns made with various levels of Chungmirae leaf powder$(0-7\%)$ was studied to investigate the sensory and mechanical characteristics. Chungmirae juipyun was prepared with 3% Chungmirae leaf powder showed the most favorable tendencies in color, flavor and overall-acceptability. However, Chungmiraejulpyun prepared with $1\%$ Chungmirae leaf powder showed the most excellent tendency in taste, moistness and after-swallowing. In the texture meter measurement for Chungmiraejulpyun, hardness and springiness tended to increase with increasing Chungmirae leaf powder. Adhesiveness and cohesiveness showed significant differences. Texture characteristics of Chungmiraejulpyuns was prepared with $5\%\;and\;7\%$ Chungmirae leaf powder and stored at $20^{\circ}C$ for 60 days showed less change than those of the $0\%$ and $1\%$ groups. Gumminess and chewiness showed a similar tendency as hardness and there were significant differences due to changes in the additional rate of Chungmirae and storage time.

• Journal of the Korean Society of Food Culture
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• v.30 no.2
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• pp.213-219
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• 2015

This study was conducted to promote the utilization of fish paste containing four different amounts (0%: control, 2, 4, and 6%) of cheonggukjang powder. For Hunter color values, L values of samples decreased as concentration of cheonggukjang powder increased, and a and b values increased. Folding tests for all samples showed good flexibility. In the texture meter test, hardness, cohesiveness, and springiness increased according to increasing concentrations of cheonggukjang powder. However, gumminess and brittleness of fish paste were reduced upon addition of cheonggukjang powder. In the sensory evaluation, fish paste prepared with 2% cheonggukjang powder was more preferred over other fish pastes. This study suggests that addition of 2% cheonggukjang powder to fish paste could be a good way to increase cheonggukjang powder without decreasing texture acceptability.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.4 no.2
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• pp.57-61
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• 2008

During the period of retubing work for the licensing renewal, the fuel channels, calandria tubes and feeders of CANDU Reactors will be replaced, and calandria visual examination will be performed. This period is a unique opportunity to inspect the inside of the calandria. The visual inspection for the calandria vessel and its internals of Wolsong NPP is scheduled for confirming the calandria integrity. The first visual inspection for the calandria is planned in Pt. Lepreau led by AECL. The visual inspection for Wolsong NPP, led by NETEC(Nuclear Engineering & Technology Institute) of KHNP, will employ 3D laser scanner and 3D CAD Mock-up for the first time in the world, in addition to a conventional video camera. The inspection system is composed of a robot with the 3D laser scanner, a video camera and a hardness meter.

• Journal of the Korean Society of Food Culture
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• v.29 no.5
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• pp.421-427
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• 2014

This study was conducted to promote the utilization of fish paste added with green laver powder as a food product. The tested concentrations of green laver powder were 0, 3, 5, and 7%. The pH of the samples ranged from 6.71 to 6.90, and moisture content ranged from 70.03 to 70.57%. The L and a values of the samples decreased as the concentration of green laver powder increased and b value increased. Folding test in all test samples showed AA that mean good flexibility. In the texture meter test, hardness, cohesiveness, and springiness increased according to increasing concentration of green laver powder. However, gumminess and brittleness of the fish paste decreased upon addition of green laver powder. In the sensory evaluation, fish paste prepared with 5% green laver powder was preferred over other fish pastes. These results suggest that green laver powder can be applied to fish paste for the purpose of high quality and functionality.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.6
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• pp.837-844
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• 2014

This study was conducted to promote the utilization of fish paste containing loquat leaf powder (LLP). The tested concentrations of LLP were 0, 3, 5 and 7%. The pH of samples ranged from 6.75 to 6.89, and moisture content ranged from 75.23 to 76.95%. The L values of samples decreased as the concentrations of LLP decreased, and a and b values increased. In the folding test, all test samples with AA showed good flexibility. In the texture meter test, hardness, strength, springiness, gumminess and chewiness increased according to increasing concentrations of LLP. In the sensory evaluation, fish paste prepared with 5% LLP was preferred over other fish pastes. These results suggest that LLP can be applied to fish paste for the purpose of high quality and functionality.

• Journal of the Korean Society of Food Culture
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• v.28 no.6
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• pp.657-663
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• 2013

This study analyzed fish paste containing Lagocephalus lunaris powder (LLP). The moisture, crude ash, crude protein, and crude lipid content of LLP were 6.21%, 1.03%, 74.50%, and 1.21% respectively. The tested concentrations of LLP were 0, 3, 5, and 7%. The pH of the samples ranged from 6.75 to 6.89, and moisture content ranged from 75.23% to 76.95%. The L values of the samples decreased as the concentrations of LLP decreased, and the a and b values increased. In addition, the folding test results in all test samples were "AA", indicating a good mean flexibility. In the texture meter test, the hardness, strength, springiness, gumminess, and chewiness increased according to increasing concentrations of LLP. In the sensory evaluation, the fish paste prepared with 5% LLP were preferred over other fish pastes. These results suggest that LLP can be applied to fish paste for substantially increasing its quality and functionality.