• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1381-1387
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• 1998

Laminated films were prepared by casting corn-zein and fatty acid mixed solutions onto ${\kappa}-carrageenan$ films, and the effect of various fatty acids with different concentrations on the film properties such as water vapor permeabilities (WVP), tensile strength (TS) and elongation was investigated. WVP of the film decreased as concentration of fatty acids increased, and the lowest WVP value $(0.497\;ng\;m/m^2\;s\;Pa)$ was achieved with laminated films containing 30% lauric acid/corn-zein. The TS of laminated edible film seemed to decrease as the concentration of fatty acids increased, and TS of the laminated film was the highest (36.21 MPa) when the film contained 10% oleic acid. Weight loss of the minced mackerels packaged with corn-zein/carrageenan film which did not contain fatty acid was 11.7%, but weight losses of the samples packaged with oleic acid and lauric acid were 6.97% and 0.81%, respectively, after 30 days storage at $-20^{\circ}C$. The laminated films had an effect on preventing oxidation of the minced mackerels during storage because of high oxygen barrier property of the film. All of the minced mackerels packaged with the laminated films greatly reduced the peroxide value (POV) compared with unpackaged minced mackerels during storage. Also, thiobarbituric acid (TBA) values of the minced mackerels packaged with the laminated films were lower than that of unpackaged minced mackerels during storage.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.72-87
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• 2022

For the sustainable development and conservation of the national land, planned development and efficient environmental conservation must be accompanied. To this end, it is possible to induce development and conservation to harmonize by deriving factors affecting development through analysis of previously developed areas and applying appropriate management measures to areas with high development pressure. In this study, the relationship between the area where the land cover changed from forest to urbanization and various social, geographical, and restrictive factors was implemented in a regression formula through logistic regression analysis, and potential development sites were analyzed for Yongin City. The factor that has the greatest impact on the analysis of potential development area is the restrict factors such as Green Belt and protected areas, and the factor with the least impact is the population density. About 148km²(52%) of Yongin-si's forests were analyzed as potential development area. Among the potential development sites, the area with excellent environmental value as a protected area and 1st grade on the Environment Conservation Value Assessment Map was derived as about 13km². Protected areas with high development potential were riparian buffer zone and special measurement area, and areas with excellent natural scenery and river were preferred as development areas. Protected areas allow certain actions to protect individual property rights. However, there is no clear permit criteria, and the environmental impact of permits is not understood. This is identified as a factor that prevents protected areas from functioning properly. Therefore, it needs to be managed through clear exception permit criteria and environmental impact monitoring.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.367-375
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• 2009

Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. However, it is inherent the problem which causes pop-out by free-CaO contained in slag In this study, we've got the plan to assure the chemical stability of EAF slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.87-95
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• 2008

One way to shield an atypical structure to secure the occupant safety of an impact vehicle is to stack energy absorbing material modules around the structure. To be applicable to a cushion module, material must have enough energy absorbing capabilities while satisfying the safety requirements of the vehicle occupant. Static compression test of the potential materials gives a good indication which material is good for a slacking module. This paper presents the mechanical properties that a cushion material must have to satisfy the safety requirements. Static tests are performed for Quard-Guard system module, sand bag, recycled tires, Geo-Container, Geo-Cell and Expanded Polystyren (EPS) Blocks. Static test results are discussed and EPS block of $30kg/m^{3}$ density showed good potential for a cushion module. To check the dynamic effect of EPS block, drop tests have been made up to 35.6km/h impact speed. Drop test results are compared with static test results and no appreciable difference was found. To improve the EPS module property, making holes to the block is suggested and drop test are performed for the modified blocks. From the drop test results, design values are suggested.

• Nuclear Engineering and Technology
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• v.18 no.3
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• pp.218-227
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• 1986

Studies were conducted to determine the extent of oxidation and same of the mechanical property changes of Zircaloy-4 fuel cladding after it was exposed to hot steam environment. The purpose of these tests was to provide some informations on the embrittlement behavior of CANDU type fuel cladding, which could be experienced under the loss-of-coolant accident conditions. The Zircaloy fuel cladding tubes were exposed in a steam environment at the temperature of 90$0^{\circ}C$, 1,00$0^{\circ}C$. The growth of the ZrO$_2$ layer combined with an oxygen rich $\alpha$-phase layer into the Zircaloy tube material was found as a function of time t and temperature of steam exposure, E=1.1√Dt+0.002 where D is a temperature dependent diffusion coefficient. The tensile strength of the specimens exposed for a short period increased but decreased continuously with further exposure. The circumferential elongation was drastically changed with the exposure time while the hoop strength did't decrease greatly. The X-ray measurement of preferred orientation of the Zircaloy tube material indicated that grains in the as received tube were oriented such that the poles of the basal (0001) planes were predominantly radial, while the poles of the basal plane in the tube materials heattreated at 1,00$0^{\circ}C$ were oriented tangentially. It appears that this reoriented texture may contribute to lessening the decrease of the hoop strength of the heat treated Zircaloy tube material.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.4
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• pp.235-247
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• 2009

In order to elucidate the cause of Cochlodinium polykrikoides blooms in the Korea southern coastal water, we investigated observational data of water temperatures and salinities in summer and winter, obtained from the stoppage of ship by NFRDI (National Fisheries Research and Development Institute) as well as composite images by NOAA from 1995 to 2008. Cochlodinium polykrikoides blooms occurred when water temperature was approximately $25.0{\sim}26.0^{\circ}C$ and salinity was 31.00 psu on average in Narodo neighboring seas. Different thermohaline fronts were observed between the Korea southern coastal water and the open sea water in summer and winter, respectively. That is, in winter four fronts were observed between the Korea southern coastal water with low temperature and low salinity, intermediate water originated from Tsushima Warm Current, Tsushima Warm Current with high temperature and high salinity, and the China coastal water with low temperature and low salinity. In contrast, in summer two fronts were observed between the Korea southern coastal water with low temperature and high salinity, Tsushima Warm Current with high temperature and low salinity, and the China coastal water with high temperature and high salinity. These thermohaline fronts also proved to be formed by two water masses with a different physical property, in terms of T-S diagrams. Consequently, we noticed that C. polykrikoides blooms occurring in Narodo neighboring seas in summer had a close relationship with thermohaline fronts observed between the Korea southern coastal water and Tsushima Warm Current.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.103-111
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• 2012

One of the basic physical properties of the hardened cement paste, the rigidity, is deteriorated during concrete matrix forming, depending on the replacement rate of the crushed stone powder, and due to drying shrinkage. Therefore, the concrete containing crushed stone powder has been limitedly used as non-structural construction material. To improve these disadvantages, a hydrothermal reaction employing method can be considered. High-temperature and high-pressure water is involved in the hydrothermal reaction in the mixing with specific materials. The rigidity improving mechanism is related to the synthesis of calcium silicate. The calcium silicate is produced through reaction between calcium compounds and the silicic acid. Various kinds of calcium silicate can be produced depending on the CaO/$SiO_2$ mole ratio, the temperature of the hydrothermal synthesis, the pressure, and the reaction time. The product of the synthesis mechanism, tobermorite crystal, plays a pivotal role for the rigidity reinforcement. The crushed stone powder, analyzed in this study, contains 50 to 60% of $SiO_2$ and 10 to 20% $Al_2O_3$. The composite rate is appropriate to create the tobermorite crystal through formation of hardened cement matrix under the hydrothermal synthetic conditions and with the CaO in the cement. Moreover, further reinforcement was promoted using the property of material under the identical density through promoting the formation of tobermorite crystal.

• Journal of Korean Society of Steel Construction
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• v.27 no.6
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• pp.493-501
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• 2015

Superelastic shape memory alloys (SMAs) are metallic materials that can automatically recover to their original condition without heat treatment only after the removal of the applied load. These smart materials have been wildly applied instead of steel materials to the place where large deformation is likely to concentrate. In spite of many advantages, superelastic SMA materials have been limited to use in the construction filed because there is lack of effort and research involved with the development of the material model, which is required to reproduce the behavior of superelastic SMA materials. Therefore, constitutive material models as well as algorithm codes are mainly treated in this study for the purpose of simulating their hysteretic behavior through numerical analyses. The simulated curves are compared and calibrated to the experimental test results with an aim to verify the adequacy of material modeling. Furthermore, structural analyses incorporating the material property of the superelastic SMAs are conducted on simple and cantilever beam models. It can be shown that constitutive material models presented herein are adequate to reliably predict the behavior of superelastic SMA materials under cyclic loadings.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.133-140
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• 2016

Software reliability in the software development process is an important issue. Software process improvement helps in finishing with reliable software product. Infinite failure NHPP software reliability models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, we were proposed the reliability model with the exponential and inverse exponential distribution, which made out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on mean square error (MSE) and coefficient of determination($R^2$), for the sake of efficient model, were employed. Analysis of failure, using real data set for the sake of proposing the exponential and inverse exponential distribution, was employed. This analysis of failure data compared with the exponential and inverse exponential distribution property. In order to insurance for the reliability of data, Laplace trend test was employed. In this study, the inverse exponential distribution model is also efficient in terms of reliability because it (the coefficient of determination is 80% or more) in the field of the conventional model can be used as an alternative could be confirmed. From this paper, the software developers have to consider life distribution by prior knowledge of the software to identify failure modes which can be able to help.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.501-511
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• 2014

Bio-oil derived from biomass through fast pyrolysis process has the potential to displace a significant amount of petroleum fuels. However, the use of bio-oil in a diesel engine is very limited because of its poor properties, e.g., its low energy density, low cetane number, and high viscosity. Therefore, bio-oil should be emulsified or blended with other fuels that have high centane numbers. Because bio-oil has poor miscibility with petroleum fuels, the most suitable candidate fuels for direct mixing are alcohol fuels. In this study, bio-oil was blended with ethanol, and two types of cetane improvers were added to a blended fuel to improve the self-ignition property. The two types of cetane improvers, PEG 400 and 2-EHN, made it possible for bio-oil blended fuels to combust in a diesel engine with a maximum bio-oil content of 15 wt%. A high-compression-ratio piston is also proposed for the combustion of bio-oil in a diesel engine.