• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.111-112
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• 2015

There is high possibility of steel corrosion on the reinforced concrete exposed to marine environment by chloride ion penetration. And it show a big difference of concrete durability under conditions of splash zone, tidal zone, and immersion zone. Therefore, in this paper, half-cell potential and chloride ion penetration depth was measured to evaluate the durability of slag concrete by marine exposure experiment. As a result, SC70 specimen showed no steel corrosion, regardless of the marine exposed conditions. Also, a deterrent effect on chloride ion penetration by replacement of slag in tidal zone and immersion zone could be confirmed.

• Food Science and Preservation
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• v.6 no.1
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• pp.55-60
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• 1999

A three variables by three level factorial design and response surface methodology were used to determine optimum conditions for osmotic dehydration of banana. The moisture loss, solid gain, weight loss and reduction of moisture content after osmotic dehydration were increased as temperature, sugar concentration and immersion time increased. The effect of concentration was more significant than those of temperature and time on mass transfer. Color difference and titratable acidity were decreased by higher concentration. Sweetness was increased by increasing sugar concentration, temperature, immersion time during osmotic dehydration. The regression models showed a significant lack of fit (p>0.5) and were highly significant with satisfying values of R2. To optimize osmotic dehydration, based on surface response and contour plots, superimposing the individual contour plots for the response variables. the optimum conditions for this process wire 26$^{\circ}C$, 44 $^{\circ}$brix and 2 hrs for moisture content, sweetness and color difference are less than 72%, 24 obrix and 10 degree.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.3
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• pp.256-260
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• 1982

This paper presents the characteristics of fuel spray in a diesel engine. In this paper, in order to obtain spray droplet size in a diesel engine, water was injected into the cylinder at room temperature and pressure by injection system. Spray droplet size was measured by liquid immersion technique with a lubricant used as an immersion liquid for spray water from injection nozzle. In this experiment, single hole type throttle nozzle are used at same operating conditions, which included opening pressure of nozzle, fuel delivery, and injection speed. Sauter mean diameter decrease with the increase of injection pressure and decrease in injection nozzle diameter. The rate of spray penetration increased with increasing injection pressure and diameter of injection nozzle at the constant spray conditions.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.199-205
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• 2018

A geopolymer was produced from coal ash generated from an integrated gasification combined cycle (IGCC) plant and its water resistance was evaluated. For this purpose, the geopolymer specimens were immersed in water for 30 days to measure changes in microstructure and alkalinity of the immersion liquid. Particularly, the experiment was carried out with foaming status of the geopolymers and parameters of room temperature aging condition, and immersion time. The foamed geopolymer containing 0.1 wt% Si-sludge had pores with a diameter of 1 to 3 mm and exhibited excellent foamability. Also, the calcium-silicate-hydrate crystal phase appeared in the foamed geopolymer. In the geopolymer immersion experiment, the pH of the immersion liquid increased with time, because the un-reacted alkali activator remained was dissolved in the immersion liquid. From the pH change of the immersion liquid, it was found that geopolymer reaction in the foamed specimen was completed faster than the non-foamed specimen. Through this study, it was possible to successfully produce foamed and non-foamed geopolymers recycled from IGCC coal ash. Also the necessary data for the safe application of IGCC coal ash-based geopolymers to areas where water resistance is needed were established; for example, the process conditions for room temperature aging time, effect of foaming status, immersion time and so on.

• Computers and Concrete
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• v.5 no.6
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• pp.573-597
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• 2008

Among artificial intelligence-based computational techniques, adaptive neuro-fuzzy inference systems (ANFIS) are particularly suitable for modelling complex systems with known input-output data sets. Such systems can be efficient in modelling non-linear, complex and ambiguous behaviour of cement-based materials undergoing single, dual or multiple damage factors of different forms (chemical, physical and structural). Due to the well-known complexity of sulfate attack on cement-based materials, the current work investigates the use of ANFIS to model the behaviour of a wide range of self-consolidating concrete (SCC) mixture designs under various high-concentration sodium sulfate exposure regimes including full immersion, wetting-drying, partial immersion, freezing-thawing, and cyclic cold-hot conditions with or without sustained flexural loading. Three ANFIS models have been developed to predict the expansion, reduction in elastic dynamic modulus, and starting time of failure of the tested SCC specimens under the various high-concentration sodium sulfate exposure regimes. A fuzzy inference system was also developed to predict the level of aggression of environmental conditions associated with very severe sodium sulfate attack based on temperature, relative humidity and degree of wetting-drying. The results show that predictions of the ANFIS and fuzzy inference systems were rational and accurate, with errors not exceeding 5%. Sensitivity analyses showed that the trends of results given by the models had good agreement with actual experimental results and with thermal, mineralogical and micro-analytical studies.

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.1
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• pp.57-66
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• 2003

The purpose of the present study was to investigate physicochemical changes in olive flounder and korean rockfish muscle subjected to the cold brine, and to find the optimal immersion condition. Effects of various immersion conditions in a sliced raw fish quality were investigated in the rigor index, breaking strength, ATP related compounds, and lactate accumulation in the muscle. The onset of rigor-mortis was accelerated by the increase of immersion time. Also, the time reaching full rigor was shortened remarkably too. However, the rigor index of samples immersed in the cold brine decreased more than that of samples killed instantly. Rigor index was the highest in samples killed instantly, followed by 2.5 min, 5min, 7.5 min, 10 min and 15 min in order. Breaking strength of all samples immersed in the cold brine decreased significantly after reaching the maximum values. The content of ATP related compounds in olive flounder, korean rockfish were $12.0{\mu}mole/g$ and $8.3{\mu}mole/g$, respectively. However, ATP decreased in the samples immersed in the cold brine. The content of ATP was lower, at the optimal condition and then it was increased. Also, lactates increased, at the optimal condition and then it decreased, in contrast with the ATP. The results suggested that the optimal immersion condition of olive flounder and korean rockfish was at -${12.5}^{\circ}C$ for 5min.

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.647-657
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• 2015

The purpose of this study is to investigate how young children's excessive immersion in smartphone games affects their prosocial and problematic behavior. To achieve the purpose, a qustionnaire survey was conducted with 147 children aged 3 to 5 going to two kindergartens and two child-care centers which were judged to have similar social and economic conditions, their mothers, and 16 teachers in charge of them. For data processing, SPSS 18.0 program was used to conduct frequency analysis, correlation analysis, and simple regression analysis. The study results were presented as follows. First, the more seriously the young children had excessive immersion in smartphone games, the more negatively their prosocial behavior was influenced. Secondly, the more severely the young children had excessive immersion in smartphone games, the more problematic behavior the young children had. This study is meaningful in the point that it analyzed the impact of their addiction in smartphone games on their prosocial and problematic behavior, and thereby helped to improve a plan of effectively using smartphones as educational media.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.145-149
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• 2006

The effect of alkaline environmental condition on durability of GFRP composites according to additives has been investigated. Additives used were polyvinyl alcohol (PVA), kaolin and alumina powder. Weight gains increased with immersion time in all GFRP composites at $80^{\circ}C$. But weight gain of specimen added PVA did not differ through the whole immersion time in both tap water and alkaline solution at 20 and $80^{\circ}C$. Tensile strength decreased with immersion time in all environment conditions. Tensile strength of GFRP composites regardless of additives decreased rapidly up to 5 days of immersion and then decreased slowly up to 30 days in alkaline solution environment at $80^{\circ}C$. The weight gains were not much difference in both tap water and alkaline solution at $20^{\circ}C$. But the ones of GFRP composites added PVA was smaller than the composites without additive in all aqueous at $20^{\circ}C$. Test strength of GFRP composites added polyvinyl alcohol has improved through the whole immersion time in both tap water and alkaline solution environment at $20^{\circ}C$.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.24-30
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• 2013

Today, the modification of carbon foam for high performance remains a major issue in the environment and energy industries. One promising way to solve this problem is the optimization of the pore structure for desired properties as well as for efficient performance. In this study, using a sol-gel process followed by carbonization in an inert atmosphere, hollow spherical carbon foam was prepared using resorcinol and formaldehyde precursors catalyzed by 4-aminobenzoic acid; the effect of carbonization temperature and re-immersion treatment on the pore structure and characteristics of the hollow spherical carbon foam was investigated. As the carbonization temperature increased, the porosity and average pore diameter were found to decrease but the compression strength and electrical conductivity dramatically increased in the temperature range of this study ($700^{\circ}C$ to $850^{\circ}C$). The significant differences of X-ray diffraction patterns obtained from the carbon foams carbonized under different temperatures implied that the degree of crystallinity greatly affects the characteristics of the carbon form. Also, the number of re-impregnations of carbon form in the resorcinol-formaldehyde resin was varied from 1 to 10 times, followed by re-carbonization at $800^{\circ}C$ for 2 hours under argon gas flow. As the number of re-immersion treatments increased, the porosity decreased while the compression strength improved by about four times when re-impregnation was repeated 10 times. These results imply the possibility of customizing the characteristics of carbon foam by controlling the carbonization and re-immersion conditions.

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.107-113
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• 2022

In this paper, we propose the relationship between the expectation of home training, exercise commitment, and exercise continuation intention. The subject of this study is the police officers belonging to the Busan and Gyeongnam Provincial Police Agency as of March 2021. Among them, a survey was conducted targeting 337 people who had experience participating in home training. As a result of the study, first, it was found that the expectations of home training were significantly correlated with exercise immersion and exercise continuation intention factors. Second, it was found that the expectation of home training participants had a significant effect on exercise immersion and exercise continuation intention. Third, exercise immersion of home training participants was found to have a significant effect on exercise continuation intention. Home training will be usefully used to prepare physical conditions for various public safety situations. If you training with a long-term plan rather than short-term training, you will be able to achieve the effect that home training seeks.