• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.189-199
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• 2011

Installation of a proper root barrier in a green roof system is very important in order to protect the concrete slab of roof and the root penetration in the waterproofing layer. To select the proper root barrier materials and methods, it is necessary to understand the environmental conditions affecting the waterproofing-root barrier system in green roof construction site. Therefore, we suggested as the environmental performance indexes four kinds of performance requirements; root penetration, chemical attack by chemical agent or fertilizer, load impact by soil depth and size of plant, and water pressure. The related four test methods were suggested for the inspection of these performance indexes. In this research, we could suggest for kinds of test methods as standard test methods to evaluate the environmental performance of waterproofing-root barrier for greening roof system.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.13-21
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• 2016

A hybrid precast concrete beam system with a simple rigid connection was proposed to compensate the limitations and shortcomings of the conventional bolt connection associated with the H-beams embedded into concrete beams. Three beam specimens with fixed both ends were tested under one-point top cyclic loading to explore the effectiveness of the developed hybrid beam system in transferring externally applied flexure to a column. The main parameter considered was the length ($L_s$) of H-beam, which was selected to be $0.25L_I$, $0.5L_I$, and $1.0L_I$, where $L_I$ is the distance from the support to the point of inflection. All beam specimens showed a better displacement ductility ratio than the reinforced concrete beams with the same longitudinal reinforcement index, indicating that the cyclic load-deflection curve and ductility were insignificantly affected by $L_s$. The continuous strain distribution along the beam length and the prediction of the ultimate load based on the collapse mechanism ascertained the structural adequacy of the developed rigid connection.

• Korean Journal of Occupational Health Nursing
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• v.17 no.2
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• pp.216-223
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• 2008

Purpose: This study was performed to evaluate the worker's job stress status in the workplace of a local area. Method: Data were collected from October to December, 2007. The subjects were 208 workers at 2 work sites in Busan Metropolitan area, who were examined using Job-Strain-Model Questionnaire. Data were analyzed by SPSS 12.0 Win Program to get the percentage, mean, standard deviation, t-test, ${\chi}^2$-test, ANOVA. Results: The results of this study were as follows: In the mean sub-factors job stress level, the mean of job demand was $28.7{\pm}4.4$(median 29.0), the mean of job discretion was $54.7{\pm}8.2$(median 54.0), the mean of social support was $21.8{\pm}2.9$(range:8-32). This study's subjects were appeared as active group with relatively higher score of job demand and job discretion than the average value of those. There was no statistically significant difference of general characteristics among the different job strain groups. There was statistically significant difference with of social supports among the different job strain groups. Conclusion: In conclusion, the subjects of this study's were active group. Thus, it is suggested that it is be necessary to repeated the education of the job task work for active group with high score of job demand and job discretion.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.8 s.251
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• pp.931-940
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• 2006

Defect assessment of a weld zone is important in fitness-for-service evaluation of plant components. Typically a J and $C^*$ estimation method for a defective homogeneous component is extended to a mismatched component, by incorporating the effect due to the strength mismatch between the weld metal and the base material. The key element is a mismatch limit load. For instance, the R6/R5 procedure employs an equivalent material concept, defined by a mismatch limit load. A premise is that if a proper mismatch limit load solution is available, the same concept can be used for any defect location (either a weld centre defect or a heat affected zone (HAZ) defect) and for any material combination (either two-material or multi-material combinations; either similar or dissimilar joints). However, validation is still limited, and thus a more systematic investigation is needed to generalise the suggestion to any geometry, any defect location and any material combination. This paper describes the effect of structural geometry on the $C^*$ integral for defective similar welds, based on systematic elastic-creep 2-D and 3-D finite element (FE) analyses, to attempt to elucidate the questions given above. It is found that the existing 'equivalent material' concept is valid only for limited cases, although it provides conservative estimates of $C^*$ for most of cases. A modification to the existing equivalent material concept is suggested to improve accuracy.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.297-302
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• 2007

Discharge variations of perforated hose and drip irrigation systems were examined to evaluate irrigation uniformity at different pressures and length of branch line. Evaluation using statistical uniformity indicated that button drippers performed at excellent level but drip tapes and drip hoses were a little lower level. Nominal discharge of drip irrigation systems showed at the high side within the range of regulating pressure provided by the manufacturer. It is desirable that the length of branch line for drip hose, drip tape, and button dripper should be limited to 50 m, 70 m, and 100 m, respectively. Irrigation uniformity of perforated hoses showed very low level. So it is recommended that the length of branch line for perforated hoses should be limited to $30{\sim}35m$.

• Molecular & Cellular Toxicology
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• v.5 no.1
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• pp.75-82
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• 2009

Saengshik is an uncooked and powdered functional food composed of various edible plants, and has been consumed widely due to its health benefits and convenient uptake. Recently, superfine ground saengshik, which contains a certain extent of nanoscale particles, has been commercialized to enhance efficacy, but its safety has not been determined. This study was conducted to evaluate the food safety of superfine saengshik (SS) through general toxicity examination after oral uptake in mice compared to conventional fine saengshik (FS). The SS particle size distribution was 0.479-26.303 f.1m in diameter, with about 68.92% of particles with a diameter < $0.955{\mu}m$. From our safety evaluation, the number of white blood cells (WBCs) and biochemical values in the serum fell into the normal range, and the weight of organs showed no significant difference between FS and SS groups. Histological observation of the liver, small intestine and large intestine did not show any abnormal or pathological findings under light microscopy. Our results suggest that oral intake of SS is not harmful to mice in terms of general toxicity.

• The Korean Journal of Food And Nutrition
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• v.32 no.6
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• pp.651-661
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• 2019

Suaeda asparagoides (Miq.) is a salt marsh plant, long been prescribed in traditional medicine for the treatment of hypertension and liver toxification in Asian countries. The powder of S. asparagoides was added at the ratio of 0, 5, and 10%, respectively, of grain-type Meju to manufacture Doenjang in brine according to the salt concentration (8 and 12%). After 24 weeks of fermentation, the Doenjang samples were determined to have an anti-inflammatory effect on RAW 264.7 cells. Evaluation of the anti-inflammatory effect of Doenjang added S. asparagoides powder extracted using 80% EtOH, was performed to study the inhibition of pro-inflammatory factors such as NF-κB (nuclar factor κB), NO (nitric oxide), TNF-α (tumor necrosis factor alpha), IL-6 (interleukin-6), iNOS (inducible nitric oxide synthase), and COX-2 (cyclooxygenase-2) in lipopolysaccharide (LPS)-induced RAW 264.7 cells. The results showed that the Doenjang extracts reduced the production of NO, IL-6, COX-2, and iNOS increased in the LPS-stimulated RAW cell without cytotoxicity. In the case of the NF-κB and TNF-α there was no significant difference between the control and samples. In conclusion, these results suggest that Doenjang added with the S. asparagoides powder acts as functional fermented food with anti-inflammation effect.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.177-183
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• 2011

The susceptibility of cultivars of three bentgrass species (creeping, colonial, and velvet bentgrass) was evaluated on detached leaves assays with pink snow mold 9 isolates caused by Microdochum nivale in Petri dishes and whole plants under controlled conditions. The pink snow mold isolates obtained from infected turfgrasses on golf courses in Wisconsin were tested on response of fungicides and temperature. Detached leaf assay and susceptibility of bentgrass cultivars were evaluated with potted adult seeding during 80 days. Nine isolates were susceptible to two fungicides and were significantly different among isolates. Mycelial growth was varied in response of temperatures among isolates. There were significant differences in development and colonization of the fungus on detached leaf assay among bentgrass species include culvitars. There were significant differences on whole plants in disease severities among the three bentgrass species, particularly between tetraploids (creeping and colonial) and diploid (velvet) species, and among cultivars within each species, indicating that there are varying levels of susceptibility in species and cultivars to M. nivale. This study could be applied to evaluate the susceptibility of bentgrass to pink snow mold and also to predict a prospective evaluation of bentgrass cultivars to pink snow mold in fields in a breeding program.

• The Journal of the Acoustical Society of Korea
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• v.15 no.1E
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• pp.5-19
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• 1996

This paper proposes a loose part monitoring system (LPMS) design with a signal processing method based on fuzzy logic. Considering fuzzy characteristics of metallic impact waveform due to not only interferences from various types of noises in an operating nuclear power plant but also complex wave propagation paths within a monitored mechanical structure, the proposed LPMS design incorporates the comprehensive relation among impact signal features in the fuzzy rule bases for the purposes of alarm discrimination and impact diagnosis improvement. The impact signal features for the fuzzy rule bases include the rising time, the falling time, and the peak voltage values of the impact signal envelopes. Fuzzy inference results based on the fuzzy membership values of these impact signal features determine the confidence level data for each signal feature. The total integrated confidence level data is used for alarm discrimination and impact diagnosis purposes. Through the perpormance test of the proposed LPMS with mock-up structures and instrumentation facility, test results show that the system is effective in diagnosis of the loose part impact event(i.e., the evaluation of possible impacted area and degree of impact magnitude) as well as in suppressing false alarm generation.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.186-193
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• 2016

This study focused on the evaluation of the antioxidative effects of lotus seeds from golden colored flowers. The lotus seeds were extracted with ethanol and then fractionated into 4 fractions, ethyl acetate (EtOAc), n-butanol, methylene chloride, and n-hexane. The comparison of antioxidative activities of the extract and fractions from the lotus seeds was carried out using an in vitro radical scavenging model and the total phenol content was analyzed. Of the tested extracts and fractions, the EtOAc fraction of the lotus seeds showed the strongest 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with 96.24% at a concentration of $100{\mu}g/mL$. In addition, the hydroxyl radical scavenging activity of the lotus seed EtOAc fraction was also increased in a concentration dependent manner with the concentrations tested ranging from 5 to $100{\mu}g/mL$. Moreover, the EtOAc fraction showed the highest scavenging activity for nitric oxide and superoxide anion radicals. In particular, of all the extracts and fractions, the EtOAc fraction showed highest contents of total phenols. These results indicate that lotus seeds have potential as an antioxidative agent against oxidative stress involving reactive oxygen species. Furthermore, the EtOAc fraction of lotus seeds includes promising oxidative stress-protective compounds.