• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.43-48
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• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzaolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3∼4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2374-2382
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• 2002

Aluminum alloy/aramid fiber reinforced plastic(Al/AFRP) laminates consists of high strength metal(A15052) and laminated aramid fiber with structural adhesive bond. The mixture ratio effect of epoxy resin curing agent accelerator on the tensile strength and T-peel strength characteristic in Al AFRP laminates were investigated in this study. The epoxy. diglycidylether of bisphenol A(DCEBA), It'as cured by methylene dianiline(MDA) with or without an accelerator(K-54). Eight different kinds of resin mixture ratios were selected for the test , five kinds of Al/AFRP laminates were named as Al/AFRP(1) and three others of Al/AFRP laminates were named as Al/AFRP(2). The comparison of tensile strength and T-peel strength with variation of resin mixture ratio were studied. Respectively. Al/AFRP(1) and Al/AFRP(2) indicated approximately 6.0 times and 7.0 times more improved maximum tensile strength in comparison with those of monolithic A15052. Al/AFRP(2) indicated approximately 1.5 times more impoved maximum T-peel strengths in comparison with those of Al/AFRP(1). As results. Al/AFRP(2) turned out to have more effective characteristics on the tensile strength and T-peel strength than those of Al/AFRP(1).

• Korean Journal of Materials Research
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• v.16 no.9
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• pp.533-537
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• 2006

The effects of binary solvent mixtures with various ratios of toluene and ethanol on the properties of slurries and green sheets were investigated. Viscosity of slurry was changed by varying the ratio of solvent mixture which affected the solubility of binder. The relative solvency behavior of a solvent mixture could be predicted with the Hildebrand solubility parameter(${\delta}$) and hydrogen bonding index( ${\gamma}$). The minimum viscosity, the best dispersion of binder, was reached at the composition of toluene:ethanol=4:6, which corresponded to our forecast. The mechanical properties of green sheets related to evaporation of solvents were influenced by the composition of the solvent mixture. At the azeotrope the skin was formed on a drying cast during the drying process because of fast evaporation. At a range of concentrations over 50wt% toluene, green sheets could not be fully dried at low temperature due to excessive toluene. The mechanical properties of green sheets were excellent at the azeotrope-like composition of toluene:ethanol=4:6 which has a little excess of toluene over the azeotrope.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.140-146
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• 2014

This study investigated the engineering characteristics of non-sintering binder-stabilized mixtures consisting of different ratios of a hardening agent(3%, 6%, 9%, 12%) for recycling industrial by-products through several series of laboratory tests. The hardening agents consisted of two kinds of non-sintering binders(NSB-1, NSB-2), which were developed by using inter-chemical reactions among blast furnace slag, phospho-gypsum, and an alkali activator. In addition, ordinary Portland cement(OPC) was used to compare the engineering characteristics of the stabilized mixture. An unconfined compressive test showed that the unconfined compressive strength increased with the curing time and mixing ratio. Experimental test results indicated that the 7-day strength of the NSB-1 mixture was similar to that of the OPC mixture. However, its 28-day strength was higher than that of the OPC mixture. The secant module of elasticity showed a range of $E_{50}=(42-109)q_u$ regardless of the agents. Based on the results of triaxial tests, the cohesion and friction angle increased with the mixing ratio.

• Journal of the Korean institute of surface engineering
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• v.34 no.1
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• pp.56-61
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• 2001

In this work, the surface treatment of aluminum/composites (graphite-epoxy composites) was investigated. The surface of composites was treated by $Ar^{+}$ ion beam under oxygen environment. The surface of aluminum was treated by DC plasma. The optimal condition of surface treatment for the composites was determined by measuring the contact angle as a function of ion dose. The optimal treatment condition of the aluminum was determined by measuring the contact angle and T-peel strength as a function of mixture ratio of acetylene gas to nitrogen gas. The mixture ratios used were 1:9, 3:7, 5:5, 7:3, and 9:1. The results showed that the contact angle of composites decreased from$ 81^{\circ}$ to $8^{\circ}$ as the ion dose increased from zero to $1$\times$10^{17}$ions/$\textrm{cm}^2$. The optimal condition of ion dose was $1$\times$10^{16}$ions/$\textrm{cm}^2$. The results also showed that the contact angle of aluminum was a minimum for the mixture ratio of 5:5. Similarly, the T-peel strength was a maximum for the mixture ratio of 5:5, which indicates that the optimal condition of mixture ratio of acetylene gas to nitrogen gas is 5:5.

• Culinary science and hospitality research
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• v.6 no.3
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• pp.281-289
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• 2000

By adding mushroom powder in baking white bread all the edible ingredients and numerous effectiveness of green tea can be consumed completely and the beautiful natural colors of green tea can result the variety of colors of cookies and breads. In this thesis, I used sensory evaluation and mechanical test to decide the appropriate amount of mushroom powder added in baking white bread among the ratios of 1%, 2%, 3%, 4%, 5% of mushroom powder relative to flour. I find the followings. In sensory evaluation. the color of white bread resulted from the addition of mushroom powder was most attractive in The 3% mixtures tasted most salty and other than this mixtures made no differences in salty tastes. The 3% mixture tasted most sweet and the same mixture resulted best in astringent taste. On the other hand, the overall test agreed almost with the sensory tests and there were some significant differences when p< 0.05. In summing up the above findings of our investigations, the 3% mixture of mushroom powder produces the best white Bread.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.97-104
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• 2007

The object of this work is to analyze the macroscopic spray performance and atomization characteristics between diesel and biodiesel fuels. In this study, the effects of mixture ratios of biodiesel fuel on the spray tip penetration, fuel injection rate, spray cone angle, and the atomization characteristics such as droplet size, droplets distribution, and spray arrival time according to the axial distance were investigated at various injection parameters. It is revealed that the injection rate is more affected by injection pressure than mixture ratio. And, the spray development process is closely matched between diesel and biodiesel fuels. However, the droplet atomization characteristics of biodiesel shows deteriorated results as the mixture ratio of biodiesel increased because of the high viscosity and density.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.27-33
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• 2004

The Noise generation mechanisms of propane laminar premixed flames on a slot burner have been studied experimentally. The sound levels and frequencies were measured for various mixture flow rates (velocities) and equivalence ratios. The primary frequency of self-induced noise increases with the mean velocity of mixture as $f{\;}{\propto}{\;}U_f^{1.144}$ and the measured noise level increases with the mixture flow rate and equivalence ratio as $p{\;}{\propto}{\;}U_f^{1.7}$$F^{8.2}$. The nature of flame oscillation and the noise generation mechanisms are also investigated using a high speed CCD camera and a DSRL camera. The repetition of sudden extinction at the tip of flame is evident and the repetition rates are identical to the primary frequencies obtained from the FFT analysis of sound pressure signals. CH chemiluminescence intensities of the oscillating flames were also measured by PMT with a 431 nm(10 FWHM) band pass filter and compared to the pressure signals.

• Journal of Welding and Joining
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• v.20 no.2
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• pp.65-70
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• 2002

This study was to evaluate GMA welding characteristics of the A15083-O aluminum alloy according to the shield gas mixing ratio and heat input change. The GMA welding of the base metal was carried out with flour different shield gas mixing ratios(Ar100%+He0%, Ar67%+He33%, Ar50%+He50%, and Ar33%+He67%). Regarding the if1uence on the bead shape of the shield gas mixing ratio and heat input, the bead width was greatest in Ar100%+He0% mixture. But the penetration depth and area were greatest in Ar33%+He67% mixture considering that the lower Ax gas ratio, the higher bead depth and area. Also, dilution was also best in the shield gas mixing ratio. The size and number of deflects were least in Ar33%+He67% mixture. Higher He gas ratio resulted in less deflects detected by the radiographic inspection.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.273-276
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• 2003

The non-evaporable water and calcium hydroxides were measured by TG/DTA for studying the temperature effect on hydration of concrete mixture. The experimental parameters introduced in this study were the curing temperatures, ages and W/C ratios. The mixing temperature was also controlled to improve the efficiency of experimental work. While the mixture cured at high temperature showed the large quantity of non-evaporable water and calcium hydroxides at early age, the production rate of these hydration products was decreased as increasing the curing age, and the quantity of hydration product became smaller than that of the corresponding mixture cured at lower temperature at later age.