• Journal of the Korea Concrete Institute
• /
• v.21 no.4
• /
• pp.501-511
• /
• 2009

This study was conducted to develop self-healing ability of concrete so that inspection could be available even in the event of minute cracks without complex works at any time for more economic concrete structure maintenance and longevity. A completely different method has been carried out in comparison with many of similar researches on self-healing concrete. This is a basic study on the development of self-healing concrete using microbial biomineralization. Compounds were generated except for cells by precipitation reaction of CaC$O_3$ during the microbial metabolism and we examined the use as a binder that hardens the surface of sand using biomineralization that Sporosarcina pasteurii precipitates CaC$O_3$. In result, the formation of new mineral and hardening of sand surface could be verified partly, and it was available for cracks to be repaired by calcite with organic (microorganism) and inorganic (CaC$O_3$) complex structure through the basic experiment a little bit. Therefore the use of biomineralization by this sort of microbial metabolism for concrete structure helps to develop absolute repair-concrete like this concrete with microorganism. The effect of microbial application will be one of the most important research tasks having influence on not only repair for concrete structure but also development of new materials able to reduce environmental problems.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.1
• /
• pp.146-151
• /
• 2004

To evaluate a gamgug (Chrysanthemun indicum L.) as a new food material, its physicochemical properties were analyzed. The proximate compositions of gamgug were that the moisture content 10.51%, 9.38% for crude protein, 3.47% for lipid, 4.87% for ash, 13.12% for reduing sugar, 9.03% for crude fiber, and 0.74% for vitamin C, respectively. The essential amino acid contained in gamgug accounted for 41.42% of the total amino acid, while the non-essential amino acid accounted for 58.58%. It was shown that the fatty acid consisted of 6 different kinds, of which 22.63% for palmitic acid followed by 17.51% for linoleic acid, 12.76% for linolenic acid, 4.36% for myristic acid, 3.16% for oleic acid, and 0.61% for stearic acid, respectively. The content of minerals was that K was 847.4 $\mu\textrm{g}$/g which was the largest, Mg 369.0 $\mu\textrm{g}$/g, Ca 300.8 $\mu\textrm{g}$/g, and Na 61.4 $\mu\textrm{g}$/g, respectively. It was also shown that gamgug contained 45 different kinds of volatile flavor compounds, of which a docosane accounted for 9.4%, a benzene, 1-(1,5-dimethyl-4-hexenyl)-4-methyl-benzene for 5.8%, and camphor for 5.4%, respectively.

• Journal of the Korean Ceramic Society
• /
• v.34 no.2
• /
• pp.163-170
• /
• 1997

The retarding effects of MgSiF6.6H2O on the hydration of portland cement were studied. The setting time, flow value and compressive strength of mortar were measured and the mechanism of retardation was also studied by ion concentration in solution, SEM, BET, and X-ray diffraction. The results are as follows ; 1. Setting time was delayed by the addition of MgSiF6.6H2O. 2. The flow value of mortar decreases depending upon the amount of MgSiF6.6H2O. 3. The compressive strength was almost same or some increase on 28 days hydration. 4. The main retardation mechanism of MgSiF6 on the hydration of portland cement may be explained by the following hypothesis. MgSiF6 depressing the Ca++ and K+ ion concentration of cement paste solution be-cause of the recrystalization of K2SiF6 and CaF2 phase. The new products of K2SiF6 and CaF2 deposit on the surface of unhydrated cement powder and harzard the mass transfer through these layer. The low con-centration of Ca++, K+ ion in solution was decreasing the hydration rate of portland cement.

• Korean Journal of Food Science and Technology
• /
• v.45 no.2
• /
• pp.213-220
• /
• 2013

Two types of onions cultivated with different methods of sulfur application (designated as S-1 and S-2) were examined for their physicochemical and sensory properties, and then compared with onions without sulfur application as a control. During cultivation, dietary sulfur methylsulfonylmethane (MSM) was sprayed on the leaves twice starting at 2 months before harvest, with one month intervals for S-1. For S-2, the MSM was applied once onto surface soils before sowing, and then once again on the leaves at 2 months before harvest. Thiosulfinate, a major sulfur-containing compound in onions, increased in the order of control, S-1, and S-2, without noticeable differences in the strength of spicy hot taste and flavor. The S-2 onions demonstrated a total reducing capacity three times higher than control and S-1 did. It indicates that the application of sulfur would positively affect the quality of onions under the condition where sufficient time is given for soil mineralization.

• Research in Plant Disease
• /
• v.24 no.1
• /
• pp.33-40
• /
• 2018

This study was conducted to evaluate the antifungal activity of 19 agro-materials that have been registered for organic cultivation in Korea, after inoculation of pear leaves with Venturia nashicola and Gymnosporangium asiaticum. In V. nashicola, most of the nine agro- materials containing sulfur and copper completely inhibited spore germination, and some of the spores that germinated did not form appressoria. However, in only lime sulfur, Neobordeaux (cupric sulfate), and Wheengaris (sulfur)showed antifungal activity against G. asiaticum. Among the agro-materials containing plant extracts, Wheengarujaba (wood vinegar+spirits+rhubarb) inhibited conidial germination in V. nashicola and G. asiaticum by 100% and 71.6%, respectively. Among the agro-materials containing antifungal microorganisms, Cheongotan (Streptomyces griseus) reduced spore germination rate of V. nashicola to 88.8%; moreover, formation of appressoria or intracellular accumulation was not observed. Application of Topsid (Paenibacillus polymyxa) reduced spore germination rates in V. nashicola and G. asiaticum to 71.0% and 90.6%, respectively, and the formation of appressoria was not observed. Studying the antifungal activity of agro-materials because of cumulative applications under the field conditions is necessary, owing to their contact fungicidal effect and the induced-resistance by microbial metabolites and natural compounds.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.5
• /
• pp.449-470
• /
• 2018

A review of research trends on wood surface protection for exterior use obtained the following conclusions: It has been reported that inorganic compounds such as chrome and copper used as wood preservatives can protect wood from weathering. It has been shown that precoating with hydrophobic substances such as wax and oil, UV absorbers, and HALS (Hindered Amine Light Stabilizers) enhances weathering resistance on the surface of ACQ-treated wood. Opaque coatings of paint/stains and semitransparent stains on the surface of preservative treated wood can increase the synergistic effects on prevention of weathering deterioration. Also the need for repainting periodically for the protection of the preservative treated wood surface has also been suggested. ZnO or $TiO_2$ of fine particles, metal ions such as Co, Cr, Fe, Mn, Ni and Ti, and UV absorbers such as tris-resorcinol triazine derivatives, triazine and benzotriazole were introduced as additives for preventing UV in the transparent coating on wood. Several reports showed that chemical modification such as methylation, acetylation, or alkylations have made some increases the effects of preventing weathering with the increasing weight gain of chemical formulas. In heat-treated wood, there were various contradictory reports on the resistance of weathering, and there were some other reports emphasizing the necessity of painting with UV resistance, which leads to the necessity of more advanced studies.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.6
• /
• pp.733-738
• /
• 2012

Physiochemical characteristics of Luffa cylindrica (L.) Roem and antioxidant activities of its four extracts were analyzed. The chemical composition of L. Roem contained 93.69% moisture, 1.64% crude fiber, 0.52% crude protein, 0.27% crude fat, and 0.06% crude ash. The major minerals were potassium, phosphrous, and calcium. We also analyzed the major organic acids, acetic acid and succinic acid. In free amino acids, ${\beta}$-aminoisobutyric acid showed the highest concentration (100.74 mg/100 g), followed by phosphoethanolamine, urea, asparagine, and valine. Glutamic acid was the highest hydrolyzed amino acid with 1,039.99 mg/100 g followed by aspartic acid, lysine, and arginine. Four extracts from L. Roam, hot-water (LCH), cold-water (LCC), 80% ethanol (LCE), and methanol (LCM), were prepared. Total phenolic and flavonoid levels of LCE exhibited higher than three extracts. The antioxidant potential of extracts from L. Roem were investigated using DPPH, ABTS, and NBT assays. Of the four extracts, LCE had relatively high antioxidant capability on DPPH and superoxide anion radical scavenging activities (12.13%, 16.88%, and 26.61%). Based on the above results, it is suggested that an 80% ethanolic extract from L. Roem was a natural antioxidant material for health food and should be a good ingredient for functional food.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.11
• /
• pp.1375-1381
• /
• 2008

The nutritional compositions and antioxidative activities of Korean commercial blueberry and raspberry were investigated. The proximate compositions were 10.47% and 22.67% in moisture, 2.66% and 2.64% in crude protein, 2.04% and 1.67% in crude fat, 81.36% and 70.19% in nitrogen free extracts, 1.48% and 0.85% in crude fiber, and 1.99% and 1.98% in ash of blueberry and raspberry, respectively. Total phenolics content were higher in blueberry (9.028 mg/g) than in raspberry (5.340 mg/g). Major elements of blueberry and raspberry were Ca (451.34 and 97.48 mg/100 g), K (355.40 and 215.20 mg/100 g), P (321.10 and 294.04 mg/100 g), and Na (137.58 and 137.67 mg/100 g). The total amino acid contents of blueberry and raspberry were 2,011.44 mg /100 g and 2,098.82 mg/100 g, respectively. Amino acid were mainly composed of glutamic acid, aspartic acid and leucine. The DPPH and ABTS radical scavenging activities of the 80% methanol extract from blueberry and raspberry were 88.67% and 62.77%, 76.34% and 30.53% at a concentration of 5 mg/mL. The 80% methanol extract from blueberry and raspberry showed considerable antioxidative activity against reducing power in dose-dependent manner. Antioxidative activities using $\beta$-carotene-linoleate and FTC method were twice higher in blueberry than raspberry.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.17
• /
• pp.135-142
• /
• 1974

A study on the metabolism of the chemical companents of endosperm and enbryonic othans of ginseng seeds during their germination were inverstigated and the results of the changes in the contents of nitrogen conponds, carbohydrates, lipids and phosphorus conpounds are summarized as follow; 1. When a seeding grows to 5cm the fresh weight of the embryonic organ incerases 13 times compared with that of its ripened embryo veore germination and its dry weight increases 4.5 times. On the other hand, about 65% of the dry weight of the endosperm is lost. 2. During germinarion the total nitrogen content of a sedding (endosperm+embryonic organ) decreases and when the seeding grows to 5cm there is a loss of 10% of total nitrogen content. At this time, soluble nitrogen content amounts to 40~50% of the total nitrogen, a comparatively high content. 3. When theseeding grows to 5cm, the total phosphorus content decreases by 15%. During the germination period 70~75% of the total phosphorus is distributed in the embryonic orang and 25% of it is in endosperm.In the embryonic organ 35~50% of the acid soluble phosphorus is inorganic phosphorus and in the endisperm, 20~25% of the acid soluble phosphorus is inorganic phosphorus,75~80% of the organic phosphorus is contained in the endosperm. 4.One the seedling grew to 2~3cm, carbohydrates such as soluble sugars,reducong sugars,nonreducong sugars, and crude starch interconverted remarkably. 5.After stratification (just before germination) the lipid content of the endosperm is about 54% of the total weight and lipid content of the embryo is about 61%. During germination 6.81mg of the fat contained in the endosperm per seed decreases to 4.13mg while the change of fat content in the embryonic organ is not so great.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.10
• /
• pp.1034-1038
• /
• 2008

Degradative Solidification/Stabilization(DS/S) is a modification of conventional Solidification/Stabilization(S/S) that incorporates degradative processes for organic contaminant destruction with the low cost of conventional S/S. Inorganic contaminants are immobilized and chlorinated organic contaminants are destroyed by DS/S treatment. In this study, a DS/S using cement/slag/Fe(II) systems as binder was investigated to assess its effectiveness in degrading chloroform(CF) and methylene chloride(MC) contained in hazardous liquid wastes. The initial concentration of CF was 0.26 mM, 1.0 mM, 8.4 mM, 25 mM and 42 mM and Fe(II) was 200 mM. The result showed that degradation of CF in various concentration was in one kind reaction as pseudo-first-order and 95% of 0.26 mM initial concentration of CF was removed in five days. 50 mg/L of heavy metal was added in order to accelerate the rate of degradation of MC and initial concentration of MC was 3.50 mM however, degradation did not occur in system. Thus additional studies needed for degradation of MC and more studies on other reaction pathways products will help elucidate reaction mechanisms and pathways for chlorinated methanes in cement/slag/Fe(II) systems.