• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.56-64
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• 1997

Since there are three hydroxyl groups on each anhydroglucose ring of the cellulose, the renewable resources, we can get various functional papers by the chemical modification of cellulose. The reaction involving the introduction of the ${\beta}$-cyanoethyl ($-CH_2-CH_2$-CN) group into organic substances containing reactive hydrogen atoms is known as cyanoethylation. Cellulose reacts with acrylonitrile in the presence of strong alkalis in a typical manner of primary and secondary alcohols to form cyanoethyl ethers. In cyanoethylation, important factors of reaction are temperature, concentration of the NaOH, and addition rate of acrylronitrile. FT-IR spectra of cyanoethyl group was confirmed at $2250cm^{-1}$, which corresponds the introduction of aliphatic nitrile group. Effect of cyanoethyl DS(degree of substitution) on strength properties was resulted that cyanoethylated BKP of DS 0.04 appeared to be the best choice for overall strength properties. Also, excellent thermal stability in aging characteristics was obtained.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2489-2497
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• 2024

The current study aims to develop new clay bricks doped with metallic waste for radiation shielding applications. The aforementioned new bricks were fabricated with various metallic waste concentrations under a pressure rate reaching ≈114 MPa and firing temperature of 1100 ℃. The impacts of the metallic waste and the firing temperature on the developed brick samples' physical, radiation shielding, and structural properties were studied. In order to identify the fabricated bricks' mineral content, the X-ray diffraction pattern was used. Additionally, the fabricated bricks' porosity and density were experimentally determined, where the porosity was reduced by 28.03%, while their densities increased by ≈ 10.5% by raising the concentration of metallic waste. The linear attenuation coefficient (LAC) for the developed brick was investigated experimentally using a NaI (Tl) scintillation detector over the 0.033-1.408 MeV energy interval. The measured LAC values were enhanced by increasing the concentrations of metallic waste within the fabricated bricks over the examined energy interval. The fabricated brick's LAC enhancement improves the gamma-ray shielding characteristics. Therefore, the fabricated bricks are a cheap and suitable choice for radiation protection applications.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.45-49
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• 2010

To reduce the astringent taste of lotus root, the effects of various treatment methods such as drying, soaking, steaming and roasting on the physicochemical properties and sensory characteristics were investigated. The following process conditions were selected: 1) drying (D), 2) soaking followed by drying ($SK{\rightarrow}D$), 3) steaming followed by drying ($ST{\rightarrow}D$), 4) drying followed by roasting ($D{\rightarrow}R$), 5) soaking and then drying followed by roasting ($SK{\rightarrow}D{\rightarrow}R$), 6) steaming and then drying followed by roasting ($ST{\rightarrow}D{\rightarrow$}. The tannin content of the lotus root was lowest when it was treated by steaming followed by drying ($ST{\rightarrow}D$). The astringent taste of lotus root was reduced by steaming, and the roasted taste was improved by roasting in terms of sensory and flavor characteristics. Consequently, lotus root treated by steaming and then drying followed by roasting ($ST{\rightarrow}D{\rightarrow}R$) showed the highest preference with respect to astringent and roasted taste.

• Journal of the Korean Geotechnical Society
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• v.25 no.11
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• pp.87-103
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• 2009

To determine the reliable probabilistic distribution model of geotechnical properties, outlier and randomness test for analysis data, parameter estimation of probabilistic distribution model, and goodness-of-fit test for model parameter and probabilistic distribution model have to be performed in sequence. In this paper, the probabilistic distribution model's geotechnical properties of Songdo area in Incheon are estimated by the above proposed procedure. Also, the coefficient of variation (COV) representing the variability of geotechnical properties is determined for several geotechnical properties. Reliable probabilistic distribution model and COV of geotechnical properties can be used for probability-based design procedure and reasonable choice of design value in deterministic design method.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.34 no.4
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• pp.259-283
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• 2023

This study acknowledges that prevailing regulation concerning for the long-term preservation of electronic records focus mainly on document types, neglecting the preservation of electronic records from various administrative information systems. With the growing interest in data management in the era of big data, it is imperative to establish clear standards for the long-term preservation of datasets. The choice of preservation format for electronic records is based on the specific standards for each type of electronic record. These standards are formulated according to the significant properties relevant to the electronic record type. This study aims to identify the significant properties of electronic records of each record type, before creating specific preservation format selection criteria for these record types. To achieve this, we reviewed and analyzed R&D studies by the National Archives of Korea and the NARA in the United States. As a result of the research, 9 significant properties were identified for database-type entities, and 7 significant properties were identified for structured data-type entities.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.509-512
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• 2011

To study the effect of freezing rate on the quality of freeze-dried rice porridge, freeze-dried rice porridge products were prepared with rice porridge pre-frozen at three different temperatures of -20, -40, and -70$^{\circ}C$. The porridge properties such as microstructure, mechanical properties, textural properties, and rehydration rate were determined. Scanning electron microscopy images indicated that fewer air cells were obtained with a larger size of freeze-dried rice porridge frozen at -20$^{\circ}C$ compared with that frozen at -40 and -70$^{\circ}C$. In contrast, quick frozen products at -70$^{\circ}C$ had more dense texture with higher mechanical strength, whereas slow frozen products exhibited higher rehydration rates than those of quick frozen products. In conclusion, the proper choice of pre-freezing temperature plays a decisive role when preparing freeze-dried rice porridge with optimum quality and convenience.

• Communications for Statistical Applications and Methods
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• v.15 no.2
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• pp.283-292
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• 2008

Smoothing parameter or bandwidth plays a key role in nonparametric classification based on kernel density estimation. We consider choosing smoothing parameter in nonparametric classification, which optimize the Bayes risk. Hall and Kang (2005) clarified the theoretical properties of smoothing parameter in terms of minimizing Bayes risk and derived the optimal order of it. Bootstrap method was used in their exploring numerical properties. We compare cross-validation and bootstrap method numerically in terms of optimal order of bandwidth. Effects on misclassification rate are also examined. We confirm that bootstrap method is superior to cross-validation in both cases.

• KSBB Journal
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• v.23 no.4
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• pp.335-339
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• 2008

Biodiesel is an alternative and renewable energy source, which is hoped to reduce global dependence on petroleum and environmental problem. Biodiesel produced from a variety of oil sources such as vegetable oil, animal fat and waste oils, and has properties similar to those associated with petro-diesel, including cetane number, volumetric heating value, flash point, viscosity and so on. In this study, we investigate the effect of quality of raw materials on alkali-catalyzed transesterification for producing of biodiesel. The increase of content of free fatty acid and water in oil were caused the sharp decrease of conversion yield. Also, the low purity of methanol in reactant was inhibited the reaction rate. In the case of addition of sodium sulfate as absorbent to prepare catalyst solution, the content of fatty acid methyl ester in product was increased more about 1.6% than that of control. However, the addition of zeolite, sodium chloride and sodium sulfate as absorbent in reactant to remove water generated from reaction did not show any enhancement in the reaction yield. This result may provide useful information with regard to the choice and preparation of raw materials for more economic and efficient biodiesel production.

• Journal of Navigation and Port Research
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• v.40 no.5
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• pp.337-343
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• 2016

The core decisions of bulk shipping businesses can be summarized as the timing and the choice of period for which carrying capacity is traded. In particular, frequent decisions to trade freight either with repeated spot transactions or with a one-off long-term deal critically impact business performance. Even though a variety of freight trading strategies can be employed to facilitate the decisions, chartering practitioners have not been active in utilizing these strategies, and academic research has rarely proposed applicable solutions. The specific properties of freight as a tradable commodity are not properly reflected in existing studies, and limitations have been reported in their application to the real world. This research focused on the establishment of applicable freight trading strategies by taking into account two properties of freight: time perishability and term-dependant pricing. In addition to traditional trading strategies, artificial neural networks were applied for the first time to the test of freight trading strategies. The performances of the trading strategies were measured and compared to produce a remarkable outperformance of the ANN. This research is expected to make a significant contribution to chartering practices by enhancing the quality of chartering decisions and eventually enabling the effective management of freight rate risk. In addition to methodological expansion, the result will propose a way to approach the controversial issue of freight market efficiency.

• Textile Coloration and Finishing
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• v.24 no.3
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• pp.221-231
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• 2012

Rayon fabrics were treated with some commercial non-formaldehyde and low-formaldehyde resins, and then their effect on the physicochemical properties of fabrics, including formaldehyde release, tear strength, shrinkage, and wrinkle recovery, were investigated respectively. Rayons treated with non-formaldehyde resin, little formaldehyde release was observed. Considering other factors, the optimal concentration of non-formaldehyde resin was shown to be 11-13%, and curing temperature was $170{\sim}175^{\circ}C$. In case of low-formaldehyde type, 9-11% resin concentration and curing temperature of $170{\sim}180^{\circ}C$ were recommended for optimal finishing condition. The choice and combination of resins and catalysts were also important factors, and preliminary considerations before resin-finishing of rayon are also important to get much better results.