• Computers and Concrete
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• v.24 no.3
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• pp.193-206
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• 2019

Although concrete is the most widely used construction material, its deficiency in shrinkage and low tensile resistance is undeniable. However, the aforementioned defects can be partially modified by addition of fibers. On the other hand, possibility of adding waste materials in concrete has provided a new ground for use of recycled concrete aggregates in the construction industry. In this study, a constant combination of recyclable coarse and fine concrete aggregates was used to replace the corresponding aggregates at 50% substitution percentage. Moreover, in order to investigate the effects of fibers on mechanical and durability properties of recycled aggregate concrete, the amounts of 0.5%, 1%, and 1.5% steel fibers (ST) and 0.05%, 0.1% and 0.15% polypropylene (PP) fibers by volumes were used individually and in hybrid forms. Compressive strength, tensile strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, toughness, elastic modulus and shrinkage of samples were investigated. The results of mechanical properties showed that PP fibers reduced the compressive strength while positive impact of steel fibers was evident both in single and hybrid forms. Tensile and flexural strength of samples were improved and the energy absorption of samples containing fibers increased substantially before and after crack presence. Growth in toughness especially in hybrid fiber-reinforced specimens retarded the propagation of cracks. Modulus of elasticity was decreased by the addition of PP fibers while the contrary trend was observed with the addition of steel fibers. PP fibers decreased the ultrasonic pulse velocity slightly and had undesirable effect on water absorption. However, steel fiber caused negligible decline in UPV and a small impact on water absorption. Steel fibers reduce the drying shrinkage by up to 35% when was applied solely. Using fibers also resulted in increasing the ductility of samples in failure. In addition, mechanical properties changes were also evaluated by statistical analysis of MATLAB software and smoothing spline interpolation on compressive, flexural, and indirect tensile strength. Using shell interpolation, the optimization process in areas without laboratory results led to determining optimal theoretical points in a two-parameter system including steel fibers and polypropylene.

• Journal of Sericultural and Entomological Science
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• v.21 no.2
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• pp.11-19
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• 1979

This has been carried out how the sericin insoluble fixations of raw silk should be with potassium alum. This is learned from the leather tanning technique which the process works with collagen, a kind of proteins. Former reports had shown such works, however, they did not consider the moisture absorbability after their process reports by using chromium alum, formalin or vinyl acetate grafting. This report, however, paid attention to protect such absorbability as well as sericin fixation, so far it may be useful for plactical use of silk. In order to clear how the sericin is fixed with such chemicals, fundermental mechanism of weding process and chemical reaction against proteins were also discussed. The obtained results of the report are as followings. 1. Alum should not be treated for raw silk with high temperature bath like other reports because such treat induces raw silk to be stiffly after the treat. 2. It is recommended that raw silk should be treated with alum solution at room temperature for more than three hours. Even in this case, the use of only alum with raw silk could to fix sericin some how, but it increased the water proofness of the silk. 3. 1% of alum solution was found to be able to fix the sericin of raw silk. 4. In case we consider only sericin fixations, a combination treat of 1% alum for three hours and 0.5% NaOH for ten minutes method showed the best result. 5. In case we consider sericin insoluble fixation and moisture absorbility, the reversive combination of the above process was found to be the best results. 6. Sericin fixing evidence was shown with drying feature curves of wed each treated silk where we could to analyze how the chemical nature is changed after each treat. 7. Deguming ratio may be obtained up to 4.3% after the alum combination treat with regular raw silk. Such ratio was considered to be good enough for the purpose when the textile is washed with warm soap water. 8. Moisture absorbability of the combination treat of alum and NaOH was found to be good enough as well as non treated silk. 9. The tenacity and elongation of the treated silk did not change even after three month. 10. Above all, this method is considered to be better process than other coloured fixing (tannin method. Cr-alum method) or smell fixing (formalin method. vinyl acetate method).

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.325-329
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• 2014

To maintain the quality of sweet persimmon during storage, the samples were treated with a combination of 50 ppm $ClO_2$ and 0.1% fumaric acid after harvest, packaged with low density polyethylene film, and stored at $1{\pm}1^{\circ}C$ for 35 days. The combined treatment reduced the populations of total aerobic bacteria, yeast and molds by 1.82 and 2.07 log CFU/g, respectively, compared to the control. During storage, hardness of all samples decreased, but total soluble solids and weight loss were not significantly different among treatments. In addition, high-quality dehydrated sweet persimmon was prepared using red algae extract as a dehydrating agent. The rehydration ratio and vitamin C content of red algae extract-treated sample were greater than those of hot-air dried sample. These results suggest that the combined treatment of $ClO_2$ and fumaric acid can be useful for maintaining microbiological safety of sweet persimmon during storage and dehydration of sweet persimmon slices using red algae extract is an efficient drying method for the preparation of high-quality dehydrated sweet persimmon.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.593-600
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• 2016

The paper presented investigates the effects of kaolinite on strength properties of alkali-activated multi-component cement. The binders of this study was blended of ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF) and kaolinite (KA). In this study, the specimens of combination of 20%~70% GGBFS, 10%~60% FA, 10% SF (constant ratio) and 10%~50% KA binder were used for strength properties tests. The water/binder ratio was 0.5. The binders (GGBFS + FA + SF + KA) was activated by sodium hydroxide (NaOH) and sodium silicate ($Na_2SiO_3$) was 10% by total binder weight (10% NaOH + 10% $Na_2SiO_3$). The research carried out is on the compressive strength, water absorption, ultrasonic pulse velocity (UPV) and X-ray diffraction (XRD). The compressive strength decreased as the contents of KA increase. One of the major reason for this is the low reactivity of KA compared with other raw materials used as precursors such as GGBFS or FA. The presence of remaining KA indicates that the initially used quantity has not fully reacted during hydration. Moreover, the results have indicated that increased of KA contents decreased UPV under all experimental conditions. The drying shrinkage and water absorption increased as the content of KA increase. Test result clearly showed that the strength development of multi-component blended cement were significantly dependent on the content of KA and GGBFS.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.718-731
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• 2018

The beneficial effects of lactic acid bacteria (LAB) have been intensively investigated in recent decades with special focus on modulation of the host intestinal microbiota. Numerous discoveries of effective probiotics are driven by a significantly increasing demand for dietary supplements. Consequently, technological advances in the large-scale production and lyophilization are needed by probiotic-related industries for producing probiotic LAB for commercial use. Our study had a dual objective, to determine the optimum growth medium composition and to investigate appropriate cryoprotective additives (CPAs) for Lactobacillus salivarius, and compare its responses with other Lactobacillus species. The one-factor-at-a-time method and central composite design were applied to determine the optimal medium composition for L. salivarius cultivation. The following composition of the medium was established (per liter): 21.64 g maltose, 85 g yeast extract, 1.21 ml Tween 80, 6 g sodium acetate, $0.2g\;MgSO_4{\cdot}7H_2O$, $0.02g\;MnSO_4{\cdot}H_2O$, $1g\;K_2HPO_4$, $1.5g\;KH_2PO_4$, $0.01g\;FeSO_4{\cdot}7H_2O$, and 1 g sodium citrate. A cryoprotective additive combination comprising 10% (w/v) skim milk and 10% (w/v) sucrose supplemented with 2.5% (w/v) sodium glutamate was selected for L. salivarius, and its effectiveness was confirmed using culture-independent methods in the freeze-dried cells of the Lactobacillus strains. In conclusion, the optimized medium enhanced the species-specific cultivation of L. salivarius. On the other hand, the cryoprotective effects of the selected CPA mixture may also be dependent on the bacterial strain. This study highlights the necessity for precise and advanced processing techniques for large-scale production of probiotics in the food and feed industries.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.302-314
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• 2016

This study was carried out to confirm the effects of the knife-incising and kerfing pretreatment on the moisture content and surface check occurrence of Douglas-fir heavy timber. In the case of moisture content, the moisture gradient that formed in the inner part of the specimen was observed in all specimens. In addition, the moisture gradient was formed differently from the surface layer to 72 mm depending on the pretreatment conditions, and it was formed gradually in the kerfing than the knife-incising. In addition, it was found that the solid volume should be considered when measuring the average moisture content. In the case of surface check, the surface check occurrence was reduced in the knife-incising, kerfing, and the combination of knife-incising and kerfing than the control. In particular, the kerfing treatment was shown that the expansion of surface check width was effectively suppressed. In the case of knife-incising treatment, although the surface check was less than the control, the preventive effect on the surface check occurrence did not reach the level of the kerfing treatment.

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.582-588
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• 2002

IrO$_2$-RuO$_2$ films were deposited on plasma sprayed TiO$_2$ buffer layer above Ti metal by sol-gel and dip-coating method. Organic vehicle (ethyl cellulose and $\alpha$-terpineol) and glass frit were added to improve adherence of the coatings. Taguchi method and L$_{18}$ (2$^1$$\times$3$^{7}$ ) orthogonal arrays were evalvated in terms of current density to determine the optimal combination of levels of factors that best satisfy the bigger is better quality characteristic. The observed conditions were as fellows: ethyl cellulose (100 cp), drying temperature and time (17$0^{\circ}C$,20 min), heat treatment temperature and time (75$0^{\circ}C$,10 min), the weight ratio of IrO$_2$-RuO/powders to glass frit (99:5), final heat treatment time (120 min) and flow rate of air (5 sccm), respectively. ANOVA analysis suggested that the influence of the factors within $\alpha$= 0.1 was significant with a 90% confidence level.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.639-645
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• 2014

For the construction materials, concrete, as the most widely used material, is focused on its improvement of performance. Although concrete has many advantages of easiness of handling, economical benefits, and high compressive strength, low tensile strength, brittleness and drying shrinkage are reported as the drawbacks of concrete. Hence, to solve these drawbacks of concrete, many research has conducted especially using fiber-reinforced concrete technology. Especially, HPFRCC which has high volume of fiber reinforcement was suggested as a solution of these drawbacks of normal concrete with increased ductility while it has the possibility of workability loss with fiber clumping which can cause low performance of concrete. Therefore, in this paper, optimized fiber combination with either or both metal and organic fibers is suggested to provide better performance of HPFRCC in tensile strength and ductility. As the results of experiment, better workability was achieved with 1 % of single fiber rather than multiple fibers combinations, espeically, short steel fiber showed the best workability result. Furthermore, in the case of organic fibers which showed higher air content than steel fibers, higher compressive strength was achieved while lower tensile and flexural strength were shown.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.3
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• pp.71-76
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• 2014

Master packaging system is a technology combining primary and secondary packaging to preserve the fresh produce in the supply chain. Master packaging system with tailor-designed gas transfer and $CO_2$ absorber of $Ca(OH)_2$ was applied to fresh shiitake mushroom in its supply from farm to retail store. The temperature, humidity and package atmosphere were monitored through the distribution and/or storage until the packages were opened to measure the mushroom quality. Conventional perforated individual packages without secondary master pack were prepared and travelled the same path for comparison purpose. While high temperature history was observed in some initial period of actual practice of the mushroom transportation and storage unexpectedly, the package atmosphere around the produce in the master packaging system was maintained at modified atmosphere consisting of $O_2$ concentration of 0.4 to 4.2% and $CO_2$ concentration of 0.7 to 1.7%, which is known to be beneficial for the mushroom preservation. While curing the mushrooms with precooled drying was effective for quality preservation, positive effect of master packaging system could be apparent for the uncured mushroom. Harmonized combination of curing treatment, master packaging system and temperature management was suggested for the best quality preservation of the fresh shiitake mushroom.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.50-57
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• 2016

In this study, kim (dried laver) bugak ("KB"), Aster yomena bugak ("SB"), and namul (vegetables)-kim bugak (combination of Aster yomena and kim) ("NB") were prepared and their quality characteristics were investigated. NB was made by slicing Aster yomena, seasoning it with perilla seeds, attaching it to kim and applying glutinous rice paste, followed by freeze-drying. SB had a higher oil absorption rate than KB, reflecting the high oil absorption rate of namul (here, Aster yomena). DPPH radical scavenging activity was highest for SB; whereas, NB had higher DPPH radical scavenging activity than KB, indicative of the higher antioxidant capacity of namul, as compared to kim. With longer storage period, moisture content tended to be increased, while maximum load, yield stress and hardness tended to be decreased. Overall preference was in the order of NB>KB>SB, without statistical significance. Acid value and peroxide value of NB, stored at $25^{\circ}C$ for 40 days, tended to be increased gradually but did not meet the criteria for rancidity. Therefore, NB could be stored at $<25^{\circ}C$ for > 40 days. Furthermore, it would be possible to make functional bugak using a variety of namul, as well as Aster yomena.