• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.641-650
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• 2010

The concrete cracking from the restrained stress caused by the shrinkage may play significant cause of deterioration of concrete structures by allowing the permeation of sulphate and chloride ions which in turn triggers corrosion of steel reinforcement. In particular, the cracking becomes more critical as water binder ratio (W/B) is reduced and concrete strength increases. Therefore, it needs to evaluate correctly the comprehensive shrinkage behavior of concrete with high strength: high-strength concrete (HSC), ultra-highstrength concrete (UHSC). The unrestrained shrinkage tests, however, cannot estimate the net shrinkage effectively which affects cracking after full development of strength and stiffness because it does not consider the degree of restraint, strength development, stress relaxation, and so on. Therefore, in this study, both free and restrained shrinkage tests with variables of W/B (W/B of 30, 25 and 16%) and admixtures (fly ash (FA) and granulated blast-furnace slag (BFS)) for HSC, very-high-strength concrete (VHSC) and UHSC were performed. The test results indicated that the autogenous shrinkage and total shrinkage at drying condition were reduced as W/B increased and FA, BFS were added, and the cracking behavior was suppressed as W/B increased and FA was added.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.61-72
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• 2008

Leaf area index (LAI) is a key biophysical variable influencing land surface processes such as photosynthesis, transpiration and energy balance, and is a required input to estimate evapotranspiration in various ecological and hydrological models. The development of more correct and useful LAIs estimation techniques is required by these importance, but LAIs had been assumed in most LAI research through simple relations with the normalized difference vegetation index (NDVI) because the field measurement is difficult on wide area. This paper is to evaluate the MODIS LAI Product's practical use by comparing with LAIs that is derived from NOAA AVHRR NDVIs and the 2 years (2003-2004) measured LAIs of Korea Forest Research Institute in Gyeongancheon watershed (561.12 $Km^2$). As a result, the MODIS LAIs of deciduous forests showed higher values about 14 % and 15~30 % than the measured LAIs and NOAA LAIs. In the year of 2003, the MODIS LAIs in coniferous forests were 5 % higher than the measured LAIs, and showed about 7 % differences comparing with the NOAA LAIs except April. These differences come from the insufficient field data measured in partial points of the target area, and the extracted reference data from MODIS LAIs include the limits of spatial resolution and the error of incorrect land cover classification. Thus, using the MODIS data by the proper correction with the measured data can be useful as an input data for ecological and hydrological models which offers the vegetation information and simulates the water balance of a given watershed.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.9
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• pp.624-629
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• 2013

The relation between performance maintenance conditions and those cost efficiency was studied to choose an optimum operating condition in the seawater desalination pretreatment system. A hollow fiber microfiltration module, which was developed with domestic technology, was tested with the various operating conditions such as chemically enhanced backwash cycles and design dosages of a cleaning chemical. Transmembrane pressure was measured to investigate membrane fouling status and cleaning degree. In addition, economic analysis was performed to compare water production costs by the operation condition. As a result, The operation mode III, chemically enhanced backwash at once a day with 100 mg/L of sodium hypochlorite (NaOCl) was selected. The concurrent evaluation between membrane filtration performance and its economic analysis will be suitable to choose an efficient optimum condition.

• Journal of the Society of Disaster Information
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• v.10 no.3
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• pp.432-441
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• 2014

The purpose of this research is to investigate characteristics of lathe scrap for manufacturing fiber reinforced cementitious composites(FRCCs) to use lathe scrap as a alternative materials of steel fiber. It should be noted that the use of the lathe scrap for making FRCCs raised friendly environmental effect as well as economy because the lathe scrap was a by-product of steel manufactures. For this purpose, various steel scraps were collected from processing plants of metal and then their physical properties were evaluated. Also, steel scraps were classified and analyzed according to the KS D 2101 and then of these scraps, lathe scrap as a alternative materials of steel fiber was suggested. In addition, FRCCs containing lathe scraps were made according to their total volume fractions of 0.0, 0.5, 1.0, 1.5, and 2.0% for water-binder ratios of 30%, 40%, respectively, and then characteristics, such as the workability, compressive strength, and flexural strength of those were evaluated. It was observed from the test result that the compressive strengths at 7 and 28 days of FRCCs containing lathe scrap were slightly small but the flexural strengths at 28 days of those increased by 10% compared with plain concrete.

• Analytical Science and Technology
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• v.25 no.1
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• pp.83-90
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• 2012

The objective of the study was to estimate the measurement uncertainty associated with determination of creatinine (Cr) in urine samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Centrifuged urine samples (10 ${\mu}L$) were diluted with 390 ${\mu}L$ of distilled water. To 20 ${\mu}L$ aliquots of diluted urine samples, 30 ${\mu}L$ of internal standard solution (Cr-$d_3$, 5 ${\mu}g/mL$) and 10 ${\mu}L$ of acetonitrile were added and filtered. The samples (1 ${\mu}L$) were introduced into LC-MS/MS with no further pretreatment. Cr was separated on a multi-mode ODS column (Scherzo SM-C18, 75 ${\times}$ 2.0 mm I.D., 3 ${\mu}m$) and quantified by LC-MS/MS operating in MRM mode (Cr, m/z 114.0${\rightarrow}$ 86.0; Cr-$d_3$, m/z 117.0${\rightarrow}$ 89.1). The four factors that contribute uncertainty to the final result were extracted and evaluated. The principal factors of contribution to combined standard uncertainty were sample dilution, calibration curve and repeatability, while the preparation of standard solution was only a minor factor. Relative extended uncertainty of the measured concentration was 14.2% in a real urine sample.

• Journal of Animal Science and Technology
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• v.60 no.4
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• pp.9.1-9.11
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• 2018

Background: In recent years, with the prohibition of antibiotics used as growth stimulants in the nutrition of farm animals, researchers have searched for alternative natural and reliable products in order to be able to sustain the developments experienced during the use of antibiotics and to overcome the possible inconveniences. In this context, studies on evaluation of essential oils in poultry nutrition have been reported to improve the utilization of feed, stimulate the release of digestive enzymes, increase absorption in the stomach and intestines, antimicrobial and anti-parasitic effects and thus, can be an alternative to antibiotics and improve meat quality as well. Indeed, this study has been carried out to explore the effects of the addition of 150 mg/kg capsicum oleoresin (CAP), carvacrol (CAR), cinnamaldehyde (CIN) or their mixture (CAP+CAR+CIN) into the broilers' ration over sensory, physical and chemical properties in breast meat and leg meat. Methods: Experiments were conducted over 400 male and female broiler chicks (Ross-308) in 5 groups (1 control group and 4 treatment groups), each composed of 80 chicks. The control group was fed without feed additives while the second, third, fourth and the fifth groups were fed with 150 mg CAP/kg feed, 150 mg CAR/kg feed, 150 mg CIN/kg feed, and 150 mg CAP+CAR+CIN/kg feed, respectively. Results: Addition of CAP, CAR, CIN or CAP+CAR+CIN had effects on the sensory (of taste, tenderness, juiciness and overall acceptability); physical properties (of $L^*$ value and toughness), the chemical properties (of DM, CF, CP, linoleic, EPA, behenic, MUFA, PUFA and ${\Sigma}n-6$ of the leg meat), the physical characteristics (of toughness and firmness), and the chemical properties (of CF, CP, linoleic, ecosenic, EPA, lignoseric, MUFA and ${\Sigma}n-3$) of the breast meat in comparison to control group. Furthermore, while the treatments had positive impacts on thawing loss, cooking loss and water holding capacity in both breast and leg meat; no effect was observed on pH value and lipid oxidation on day 1, day 4 and day 8. Conclusion: The results strongly suggested that the addition of CAP, CAR, CIN or CAP+CAR+CIN to the rations of the broiler chicks changed the sensory, physical and chemical properties of breast and leg meat. It was also observed that these compounds were more effective when they were added to the ratio as a mixture rather than adding them individually.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.580-586
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• 2019

Fried-fish snacks containing surimi are a popular seafood product in Asia. To prepare fried-fish snacks, various ingredients are added to surimi. Among them, starch is important for producing snacks of desirable texture and taste. We investigated the physicochemical properties of fried-fish snacks containing arrowroot, potato, sweet potato, corn, and tapioca starches. The fried-fish snack with arrowroot starch showed the highest drying rate; after drying for 3 hours, the water content was unchanged. None of the starches affected the total volatile basic nitrogen values of the fried-fish snacks, which were approximately 1.5 mg/100 g, indicating freshness. The fried-fish snacks with corn and arrowroot starches had the highest brightness (L) values and the fried-fish snack with tapioca starch, the lowest L value. The hardness value of the fried-fish snack with tapioca starch was significantly higher than that of the other fried-fish snacks. In the sensory evaluation, the fried-fish snacks with arrowroot starch showed the best overall acceptance.

• Journal of Environmental Impact Assessment
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• v.19 no.5
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• pp.475-481
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• 2010

Lots of pollutants typically originating from urban transportation are accumulating on the paved surfaces during dry periods and are washed-off directly to the river during a storm. Also, paved surfaces are contributing to increase in peak flows and volume of stormwater flows. These are the main reasons why the water quality of rivers and lakes remain polluted and still below standards. Currently, several management practices are being applied in developed countries but the design standards are still lacking. This research was conducted to develop a treatment technology that can be useful to address the problems concerning runoff quality and quantity. A lab scale infiltration device consisting of a pretreatment tank and media zone was designed and tested for various flow regimes characterizing the low, average and high intensity rainfall. Based on the experiments, the high intensity flow resulted to increase in outflow event mean concentration (EMC) of pollutants, about twice as much as the average outflow EMC. However, 78 to 88% of the total suspended solids were captured and retained in the pretreatment tank because of sedimentation. The removal of heavy metals such as zinc and lead was greatly affected by the vertical placement of woodchip layer prior to the media zone. It was observed that the high carbon content (almost 50%) in the woodchip provided opportunity for enhancing its uptake of metal by adsorption. The findings implied that the reduction of pollutants can be greatly achieved by means of proper pretreatment to allow for settling of particles with a combination of using high carbon source media like woodchip and a geotextile mat to reduce the flow before filtering into the media zone and finally discharging to the drainage system.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.701-709
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• 2008

Owing to the decreased work term and the convenience of construction work in Korea, the steel deck plate system has been widely used in the construction field. Most of all, due to its good stiffness and economic consideration, the steel-wire-integrated deck plate system (or truss deck plate system) has become very popular in recent years. But although it has many advantages, the truss deck plate system has a critical defect: it gets rusty in the welding joints between the lattice steel wire and the deck plate, resulting in the cracking of such welding joints and water leakage. To address these problems, a new type of truss deck plate system, which need not be welded and does not rust, was proposed herein: the TOX deck plate system. In this study, tests were conducted on 15 specimens to evaluate the structural safety of the proposed deck plate system during the construction stage. The test parameters were as follows: the depth of the slab the length of the span the diameters of the top, bottom, and lattice steel wire and the material properties of the zinc-coated steel sheets. The test results show that the TOX deck plate system can guarantee structural safety owing to its deflection and strength.

• Toxicological Research
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• v.29 no.4
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• pp.263-278
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• 2013

The silkworm extract powder contain 1-deoxynojirimycin (DNJ), a potent ${\alpha}$-glycosidase inhibitor, has therapeutic potency against diabetes mellitus. Therefore, natural products containing DNJ from mulberry leaves and silkworm are consumed as health functional food. The present study was performed to evaluate the safety of the silkworm extract powder, a health food which containing the DNJ. The repeated toxicity studies and gentic toxicity studies of the silkworm extract powder were performed to obtain the data for new functional food approval in MFDS. The safety was evaluated by a single-dose oral toxicity study and a 90 day repeated-dose oral toxicity study in Sprague-Dawley rats. The silkworm extract powder was also evaluated for its mutagenic potential in a battery of genetic toxicity test: in vitro bacterial reverse mutation assay, in vitro chromosomal aberration test, and in vivo mouse bone marrow micronucleus assay. The results of the genetic toxicology assays were negative in all of the assays. The approximate lethal dose in single oral dose toxicity study was considered to be higher than 5000 mg/kg in rats. In the 90 day study, the dose levels were wet at 0, 500, 1000, 2000 mg/kg/day, and 10 animals/sex/dose were treated with oral gavage. The parameters that were monitored were clinical signs, body weights, food and water consumptions, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, organ weights, and histopathological examination. No adverse effects were observed after the 90 day administration of the silkworm extract powder. The No-Observed-Adverse-Effect-Level (NOAEL) of silkworm extract powder in the 90 day study was 2000 mg/kg/day in both sexes, and no target organ was identified.