• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.399-408
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• 1998

The effect of low molecular alginates feeding on the cholesterol levels and fatty acid compositions of rat serum and liver lipid were investigated. After one week basal diet feeding, four week old Sprague-Dawley male rats were fed with water soluble and acid $\cdot$alkali soluble alginate extracted from sea mustard (Undaria pinnatifida) and giant kelp (Macrocystis pyrifera), and their low molecular alginates prepared by the HCl partial hydrolysis. The feeding efficiency of the alginate fed group was ranged in 0.37$\~$0.44, which was 0.03$\~$0.05 lower than that of the basal diet group. Also, there was much less increase of liver weight in the alginate fed group. The water soluble alginate showed more significant effect in reducing the total cholesterol, free cholesterol, LDL-cholesterol, triglyceride and phospholipid of serum and liver lipid than the acid$\cdot$alkali soluble alginate. The effect was much better with low molecular alginate (reducing effect by the low-molecularization : Water soluble alginate - serum lipid; total cholesterol $59\%$, free cholesterol $65\%$, LDL-cholesterol $96\%$, triglyceride $50\%$, and phospholipid $36\%$. liver lipid: total cholesterol $4\%$, free cholesterol $62\%$, LDL-cholesterol $44\%$, triglyceride $33\%$, and phospholipid $44\%$. acid$\cdot$alkali soluble alginate - serum lipid; total cholesterol $52\%$: free cholesterol $97\%$, LDL-cholesterol $78\%$ triglyceride $32\%$, and phospholipid $64\%$. liver lipid; total cholesterol $11\%$, free cholesterol $12\%$, LDL-cholesterol $10\%$, triglyceride $27\%$, and phospholipid $21\%$). The effect of low molecular alginate feeding on the fatty acid composition of serum and liver lipid reflects the remarkable increase of polyenoic acid, over $44\%$ in serum lipid and about $70\%$ in liver lipid, comparing to the cholesterol fed group. The overall results indicated that feeding of low molecular alginates improves physiological function of rats by changing the serum and liver lipid composition.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.101-111
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• 2017

Mineral carbonation is a technology in which carbonates are synthesized from minerals including serpentine and olivine, and industrial wastes such as slag and cement, of which all contain calcium or magnesium when reacted with carbon dioxide. This study aims to develop the mineral carbonation technology for commercialization, which can reduce environmental burden and process cost through the reduction of carbon dioxide using steel slag and the slag reuse after calcium extraction. Calcium extraction was conducted using NH4Cl solution for air-cooled slag and convert slag, and ${\geq}98%$ purity calcium carbonate was synthesized by reaction with calcium-extracted solution and carbon dioxide. And we conducted experimentally to minimize the quantity of by-product, the slag residue after calcium extraction, which has occupied large amount of weight ratio (about 80-90%) at the point of mineral carbonation process using slag. The slag residue was used to replace silica sand in the manufacture of cement panel, and physical properties including compressive strength and flexible strength of panel using the slag residue and normal cement panel, respectively, were analyzed. The calcium concentration in extraction solution was analyzed by inductively coupled plasma optical emission spectrometer (ICP-OES). Field-emission scanning electron microscope (FE-SEM) was also used to identify the surface morphology of calcium carbonate, and XRD was used to analyze the crystallinity and the quantitative analysis of calcium carbonate. In addition, the cement panel evaluation was carried out according to KS L ISO 679, and the compressive strength and flexural strength of the panels were measured.

• Journal of Korea Water Resources Association
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• v.52 no.9
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• pp.627-635
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• 2019

In Korea, snow damage has been happened in the region with no snowfalls in history. Also, casual damage was caused by heavy snow. Therefore, policy about the Natural Disaster Reduction Comprehensive Plan has been changed to include the mitigation measures of snow damage. However, since heavy snow damage was not frequent, studies on snowfall have not been conducted in different points. The characteristics of snow data commonly are not same to the rainfall data. For example, some parts of the southern coastal areas are snowless during the year, so there is often no values or zero values among the annual maximum daily snow accumulation. The characteristics of this type of data is similar to the censored data. Indeed, Busan observation sites have more than 36% of no data or zero data. Despite of the different characteristics, the frequency analysis for snow data has been implemented according to the procedures for rainfall data. The frequency analysis could be implemented in both way to include the zero data or exclude the zero data. The fitness of both results would not be high enough to represent the real data shape. Therefore, in this study, a methodology for selecting a probability density function was suggested considering the characteristics of snow data in Korea. A method to select probability density function using conditional joint probability distribution was proposed. As a result, fitness from the proposed method was higher than the conventional methods. This shows that the conventional methods (includes 0 or excludes 0) overestimated snow depth. The results of this study can affect the design standards of buildings and also contribute to the establishment of measures to reduce snow damage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.619-624
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• 2016

Chlorine dioxide ($ClO_2$) gas treatment (75 ppmv, 30 min) has been suggested to improve the microbial safety of postharvest paprika in a previous study. Based on these results, in this study, an additional combined treatment using low-concentration $ClO_2$ gas-generating sticks (3 ppmv) in paprika samples during storage was carried out at $8^{\circ}C$ and 90% relative humidity to further enhance the quality and reduce the decay rate of paprika for the purpose of lengthy storage. After the combined treatment, the initial populations of total aerobic bacteria as well as yeast and molds in the paprika samples decreased by 3.04 and 2.70 log CFU/g, respectively, compared with those of the control samples, and this microbial inactivation was maintained by the low-concentration $ClO_2$ gas-generating sticks during storage. In particular, the decay rate of samples with combined treatment was significantly lower than that of the control. Vitamin C content, hardness, and color quality parameters of paprika samples were not altered by treatment, while weight loss of the samples treated with the combined $ClO_2$ gas was lower than that of the control during storage. These results indicate that the combination of two different $ClO_2$ gas treatments is effective for retaining the quality of paprika during prolonged storage.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.129-137
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• 2005

In Korea, due to the insufficiency of natural aggregates and increasing needs of crushed stones, it is necessary to examine the alkali-silica reaction of the crushed stones. The reaction produces an alkali-silica reaction gel which can imbibe pore solution and swell to generate cracks that are visible In affected concrete. In general, crushed stones are tested by petrograptuc examination, chemical method and mortar-bar method, but the most reliable method Is mortar-bar test. This study tested alkali-silica reactivity of crushed stones of various rock types using ASTM C 227 and C 1260, and compared the results of two test methods. This study also analyzed effects of particle size and grading of reactive aggregate on alkali-silica reaction expansion of mortar-bar. The effectiveness of mineral admixtures to reduce detrimental expansion caused by alkali-silica reaction was investigated through the ASTM C 1260 method. The mineral admixtures used were nv ash, silica fume, metakaolin and ground granulated blast furnace slag. The replacement ratios of 0, 5, 10, 15, 25 and $35\%$ were commonly applied for all the mineral admixtures and the replacement ratios of 45 and $55\%$ were additional applied for the admixtures that could maintain workability. The results indicate that replacement ratios of $25\%$ for ay ash, $10\%$ for silica fume, $25\%$ for metakaolin or $35\%$ for ground granulated blast furnace slag were most effective to reduce alkali-silica reaction expansion under the experimental conditions.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1360-1365
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• 2007

The purpose of this study is to present the basic data for nonpoint pollutant loads from bridge road drainage sediments using the results to analyze organic matter and heavy metals from the four bridge drainage sampling sites with sediments of different particle size ranges. The sediment sample was collected from the bridge road drainage and the masses of nine sediments fractions were obtained after drying the separated sediment in an over at $85^{\circ}C:>2,000{\mu}m$, $1,000\sim2,000{\mu}m$, $850\sim1,000{\mu}m$, $425\sim850{\mu}m$, $212\sim425{\mu}m$, $125\sim212{\mu}m$, $90\sim125{\mu}m$, $75\sim90{\mu}m$, $<75{\mu}m$. The sediment extract was analyzed water quality constituents, including chemical oxygen demand(COD), total nitrogen(T-N), total phosphorus(T-P), heavy metals and particle size distribution. The results indicate that most of particle size ranges of the bridge road sediments was $125\sim425{\mu}m$, and portion of $<75{\mu}m$ was low. But most of the pollutants are associated with the finer fractions of the load sediments. As the results of analysis, the range and average values of COD, T-N, T-P, Fe, Cu, Cr, and Pb were $177\sim198.8$ mg/kg(77.6 mg/kg), $23\sim200$ mg/kg(83 mg/kg), T-P $18\sim215$ mg/kg(129 mg/kg), and $1,508\sim5,612$ mg/kg(3,835 mg/kg), $9.2\sim69.3$ mg/kg(49 mg/kg), $19.1\sim662.2$ mg/kg(214 mg/kg), and $28.4\sim251.4$ mg/kg(114 mg/kg), respectively. The relationship between sediment size and pollutants concentration have an inverse proportion. The removal of road sediments with frequently could be reduced the significant nonpoint pollutant load, because of the bridge road sediment contains considerable micro-particles and heavy metals.

• Resources Recycling
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• v.31 no.5
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• pp.67-76
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• 2022

The furniture industry has a high possibility to create value-added and a high potential to create new occupations due to the characteristics of the industry, which mainly consists of small and medium-sized enterprises (SMEs). However, the used furniture, which has sufficient reuse value, is also crushed and used as solid refuse fuel (SRF) recently. Besides, the number of waste treatment companies continues to decrease, and it occurs congestion of wood waste. As a way to solve the issue, a business model development of remanufacturing used furniture can be suggested as an alternative due to its high circular economic efficiency. Remanufacturing business including furniture industry creates positive effects in various aspects such as economic, environmental and job creation. In other words, remanufacturing is an effective recycling way to reduce input resources and energy in the production process. The results of economic analysis show that the expected annual revenue from the single worker furniture remanufacturing site was 104 million won which is 3.11 times more than the average income of a single-worker household in Korea and its B/C ratio was estimated about 30 which means high business feasibility. Revenue through furniture remanufacturing also showed 320 times higher than that of SRF production from the perspective of weight. In addition, it is shown that the GHGs reduction from the furniture remanufacturing is 2.2 ton CO₂-eq. per year, which is similar to the amount of GHGs absorption effect of 937 pine trees or 622 Korean oak trees annually. Thus the results of this study demonstrate that it is important to adopt an appropriate recycling method considering the economic and environmental effects at the end-of-life stage.

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.172-180
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• 2023

In the current study, four groups; control, 500, 1000, and 2000 mg/L, were treated to investigate the effects of physiological and growth characteristics on Machilus thunbergii under various fertilization levels. As a result of the physiological response to the fertilization treatment, the fertilized group demonstrated relatively higher levels of A, ITE, WUEi, V_camx, PI_abs, and SFI_abs in comparison to the control. The best photosynthetic mechanism was most clearly seen at 1000 mg/L, which involved gas exchange through active stomatal opening and closing. For a productive photosynthetic mechanism. As seen in the growth response of M. thunbergii to fertilization treatment, the fertilized group has significantly higher height, DRC, leaf dry weight, stem dry weight, total dry weight, LWR, and SWR than the control group. A healthy seedling quality index was particularly evident at 1000 mg/L, and other growth indicators were also at a decent level. 500 mg /L also demonstrated growth characteristics that were comparable to those at 1000 mg/L. As a result, M. thunbergii featured the best physiological and growth characteristics in response to the fertilization treatment at 1000 mg/L, and 500 mg/L also showed a similar trend, which is considered to be a good option from an economical perspective.