• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.112-118
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• 1978

Four domestic frying oils (soybean, corn, rapeseed and rice bran oil) were studied on their changing properties according to thermal oxidation by means of chemical analysis of their compositions and measurements of various physical and chemical properties. The content of linoleic acid which is an essential unsaturated fatty acid and the total amount of unsaturated fatty acids were highest in soybean oil (53.2% and 80.3% respectively) among the unheated frying oils and the degree of its thermal degradation was lowest during the continuous heating period for 48 hours at $180^{\circ}C$. However in general, the contents of unsaturated fatty acids were sharply decreased by thermal oxidation whereas the saturated fatty acid contents ranging 10-17% were not changed considerably, which largely agreed with the results of iodine value measurements. The free acid and peroxide values were also lowest in soybean oil (0.09 and 5.6 respectively) among the unheated oils whereas an anomalously high free acid value was observed in rapeseed oil (54.8) which was packed in unleveled glass bottles. Such a high value is probably ascribed to the photo-catalyzed oxidation during storage. The viscosity measurements have shown similar values before heating, but after thermal oxidation for 32 hours the rapeseed and rice bran oils became too thick to measure viscosity by capillary flow method with heavy darkening in color.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.8
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• pp.420-427
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• 2016

This study was conducted on the sediment remediation using micro-bubble to remove fine particles. For this study, characteristics of contamination and release in sediment were analyzed. And then, the characteristics of bubbles on removal efficiency was investigated at various operation conditions. In particle size distribution of the sediment used for the study, the proportion of clay and silt (<0.075 mm) was about 7.7%, sand (0.075~4.75 mm) was about 67.8%, and gravel (${\geq}4.75$) was 24.5%. Total nitrogen (TN) and total phosphorus (TP) of the sediment were 2,790~3,260, 261~311 mg/kg respectively. Ignition loss and water content were 4.1~9.6, 32.9~53.2% respectively. In analysis of removal efficiency according to operation conditions of micro-bubble, it was the highest when operation condition is pressure 6 atm, pressurized water ratio 30%, and coagulant dosage 15 ppm. At the time, the sediment's removal efficiency was 19.9%. Accordingly removal efficiency of TN and TP were 21.4, 22.6% respectively. Finally a research was found that fine particles in sediment were almost removed by micro-bubble, which led to decrease nutrients' release at about 20.1~64.3% in comparison to sediment including lots of fine particles.

• Fire Science and Engineering
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• v.15 no.1
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• pp.23-33
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• 2001

The utility tunnels are the important facility as a mainstay of country because of the latest communication developments. However, the utilities tunnel is difficult to deal with in case of a fire accident. When a cable burns, the black smoke containing poisonous gas will be reduced. This black smoke goes into the tunnel, and makes it difficult to extinguish the fire. Therefore, when there was a fire in the utility tunnel, the central nerves of the country had been paralyzed, such as property damage, communication interruption, in addition to inconvenience for people. This paper is based on the fire occurred in the past, and reenacting the fire by making the real utilities tunnel model. The aim of this paper is the scientific analysis of the character image of the fire, and the verification of each fire protection system whether it works well after process of setting up a fire protection system in the utilities tunnel at a constant temperature. The fire experiment was equipped with the linear heat detector, the fire door, the connection water spray system and the ventilation system in the utilities tunnel. Fixed portion of an electric power supply cable was coated with a fire retardant coating, and a heating tube was covered with a fireproof. The result showed that the highest temperature was $932^{\circ}c$ and the linear heat detector was working at the constant temperature, and it pointed at the place of the fire on the receiving board, and Fixed portion of the electric power supply cable coated with the fire retardant coating did not work as the fireproof. The heating tube was covered with the fireproof about 30 minutes.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.178-187
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• 2017

The aim of this study was to investigate the effect of different light sources on the levels of glucosinolates (GSLs) in rocket salad (Eruca sativa L.). The light sources used in the study were: natural light (Control-1 or 2), red light-emitting diodes(LEDs), blue LEDs, mixed red and blue LEDs (R+B LEDs), white LEDs, fluorescent lamps (FL), and fluorescent lamps plus UV-C (FL+UV-C). Two separate experiments were conducted [Experiment I: Control-1, Red LED, Blue LED, Mix (R+B) LED and Experiment II: Control-2, White LED, FL, FL+UV-C] because of the limited number of growth chambers in our laboratory. The rate of increase in the length of rocket salad leaves was the highest under red LEDs and, FL confirming that red LED and, FL affect the growth of rocket salad. We separated and identified seven types of GSLs from the rocket salad:glucoraphanin, diglucothiobeinin, glucoerucin, glucobrassicin, dimeric 4-mercaptobutyl GSL, 4-methoxyglucobrassicin, and gluconasturtiin. The highest total GSL contents in Eexperiment I was found in plants grown under in red LEDs ($4.30{\mu}mol{\cdot}g^{-1}\;dry$ weight, DW), and the lowest under blue LEDs ($0.17{\mu}mol{\cdot}g^{-1}\;DW$). The highest total GSL contents in Experiment II was found in plants grown under FL ($13.45{\mu}mol{\cdot}g^{-1}\;DW$), and the lowest in FL+UV-C ($0.39{\mu}mol{\cdot}g^{-1}\;DW$). Especially in Experiment II, the content of dimeric 4-mercaptobutyl, which has a strong aroma and spicy flavor in rocket salad, was higher under FL and white LEDs than in Control-2, increasing by approximately 14.9 and 3.2-fold respectively. Therefore, light sources such as red LEDs, white LEDs and FL affected the accumulation of GSLs in rocket salad.

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.91-97
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• 2007

To evaluate the physiological status of laying flocks, the blood chemistry values were measured and analyzed in various ages under different feeding conditions. Total 671 birds from 48 Hyline brown hens flocks from 13 different poultry farms were bled at the ages of day(s) 1, 11, 21, 50, 80, 120, 180, 240, 300, 400, and 500. The 17 blood chemistries including glucose, lipids, proteins, enzymes, electrolytes and metabolic by-products were measured with an autoanalyzer. Blood glucose showed the highest at the hatching day not relate with the dietary carbohydrates and energy, but tended to decrease during the rest of growth stage in hens. Total blood protein, albumin and globulin increased depending on the ages even though dietary protein was decreased. Blood lipid was greatly changed at different growth stages. Cholesterol was the highest at hatching period and maintained consistently until the 120 days of age. It was increased in birds after 180 days of age. HDL was also highest in hatchery, but decreased greatly after 180 days of age. However, TG was the lowest at one day old, but was increased up to 10 times after 180 days of age compared to that of one day old. The enzyme activities were different. AST, ALT, and GGT showed comparatively contained consistently, whereas amylase was slowly decreased. Blood P, Na, K and Cl showed consistency, but Ca content was increased upto two times of the one day of age. The results from this study showed that the blood chemistry values were affected by the general metabolic status of the host with ages not by feeding conditions. Further, the standard data of age-dependent blood chemistry values in the laying flocks were obtained, which can be utilized for early detection of the changes in the physiological status occurred by the infectious or metabolic diseases. The results of these analyses seemed to be useful to increase the productivity of laying flocks through rapid and proper veterinary medical treatments.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.213-222
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• 2010

In this study, chemical compositions - holocellulose, lignin and monomeric sugars - were characterized with two poplar wood cell walls, one of which was grown at normal condition (CPW) and the other was genetically modified by antisence suppression of CCoAOMT gene expression (ACPW). Milled wood lignins were isolated from CPW and ACPW and subjected to methoxyl group, DFRC, Py-GC/MS, GPC, $^{13}C$-NMR analysis, respectively. There were few differences in holocellulose contents in both cell walls, which were determined to 81.6% in CPW and to 82.3% in ACPW. However, lignin contents in ACPW was clearly decreased by the suppression of CCoAOMT gene expression. In CPW 21.7% of lignin contents was determined, while lignin contents in ACPW was lowered to 18.3%. The relative poor solubility of ACPW in alkali solution could be attributed to the reduction of lignin content. The glucose contents of CPW and ACPW were measured to 511.0 mg/g and 584.8 mg/g and xylose contents 217.8 mg/g and 187.5 mg/g, respectively, indicating that suppression of CCoAOMT gene expression could be also influenced to the formation of monomeric sugar compositions. In depth investigation for milled wood lignin (MWL) isolated from both samples revealed that the methoxyl contents at ACPW was decreased by 7% in comparison to that of CPW, which were indirectly evidenced by $^{13}C$-NMR spectra and Py-GC/MS. According to the data from Py-GC/MS S/G ratios of lignin in CPW and ACPW were determined to 0.59 and 0.44, respectively. As conclusive remark, the biosynthesis of syringyl unit could be further influenced by antisense suppression of CCoAOMT during phenylpropanoid pathway in the plant cell wall rather than that of guaiacyl unit.

• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.175-182
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• 2014

This study investigates the free radical-scavenging activities of Amaranth (Amaranthus spp. L.) red and purple flower extracts. The methanol and hot water extracts of flower are being evaluated for its total polyphenol and flavonoid contents, scavenging activities by the DPPH and ABTS analysis, SOD-like activity, and inhibition activities of superoxide radical on the HL-60 cells and nitric oxide of the RAW 264.7 cells. The PFM (purple flower extracted with MeOH) showed the highest total phenolic and flavonoid content, 606.95 mg GAE/100 g and 254.69 mg CE/100 g, respectively. Amongst the scavenging activities of the DPPH radicals, PFM($RC_{50}=155.06{\mu}g/m{\ell}$) is the highest of all the samples. The ABTS radical-scavenging activity is also highest for PFM (53.16%) at the $250{\mu}g/m{\ell}$ concentration. But, the SOD-like activity of the PFW (purple flower extracted with hot water) increases more than 3 folds of the PFM. In the leukemia HL-60 cell, the PFM shows strongly inhibited superoxide radical generations at a concentration of $200{\mu}g/m{\ell}$ at 72.34%, which increases with 1.79 folds more than the RFW (red flower extracted with hot water). The inhibition activity of nitric oxide in Raw 264.7 cells is the highest for PMF (46.90%) at a $250{\mu}g/m{\ell}$ concentration. In conclusion, PMF show the highest flavonoid contents and the most powerful free radical-scavenging activity. Our results suggest that the increase of antioxidant activities depend on flavonoid contents. Thus, Amaranth flower can be useful for natural antioxidant compounds.

• Journal of Korean Home Economics Education Association
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• v.23 no.1
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• pp.87-111
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• 2011

The purpose of this study was to develop and evaluate practical problem-based Home Economics lesson plans applying to the multiple intelligence teaching learning strategy, focused on the unit 'Nutrition & Meals' of middle school Home Economics subject matter. To achieve this purpose, the lesson plans were developed and evaluated from the 72 middle school students in Chongju after implementing the instruction. The data from the questionnaire were analyzed by SPSS/WIN 12.0 and content analysis. The results were as follows: First, the objectives of practical problem-based 'Nutrition & Meals' Instruction using multiple intelligence teaching strategy were to understand the importance of nutrition and health in an adolescent period and to develop good eating habits. The Practical Problem was 'What should I do for good eating habits?' and the learning contents were healthy life, the kinds and functions of nutriments, food pyramid and a food guide. The learning activities were progressed by various types of teaching and learning methods including 8 types of multiple intelligence teaching strategy. The lesson plans were developed according to the process of practical problem solving model. 6 periods of lesson plans and worksheets were developed. Second, the practical problem-based instruction using multiple intelligence teaching-learning strategy were evaluated to increase students' positive learning attitudes, motivation, and good eating habits.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.855-867
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• 2018

When a weak zone exists ahead of tunnel face, the stress in the adjacent area would increase due to the longitudinal arching effect and the stability of the tunnel is affected. Therefore, it is critical to prepare a countermeasure through the investigation of the frontal weakness zone of the excavated face. Although there are several researches to predict the existence of weak zone ahead of tunnel face, such as geophysical exploration, numerical analysis and tunnel support, lack of studies on the relaxation zone depending on the width or distance from the vulnerable area. In this study, the impact of the weak zone on the formation of the relaxation zone was investigated. For this purpose, a series of laboratory test were carried out varying the width of the weak zone and the separation distance between tunnel face and weak zone. In the model test, sand with a water content of 3.8% was used to form a model ground. The model weak zone was constructed with dry sand curtains. The tunnel face was adjusted to allow a sequential excavation of upper and lower half part. load cells were installed on the bottom of the foundation and the tunnel face and measuring instruments for displacement were installed on the surface of the model ground to measure the vertical stress and surface displacements due to tunnel excavation respectively. The test results show that the width of weak zone did not affect the ground settlement while the ground subsidence drastically increased within 0.25D. The vertical stress and horizontal stress increased from 0.5D or less. In addition, the longitudinal arching effect is likely within the 1.0D zone ahead of the tunnel face, which may reduce the vertical stress in the ground following tunneling direction.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.545-555
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• 1994

The objective of the study was to provide the useful scientific data on the early rehabilitation of the legging road after timber harvesting in the forest area. This study was carried out at logging roads which were constructed during 1989 and 1994 in Mt. Baekwoon. The field survey was conducted in July, 1991. Judging from the analysis of soil bulk density, time required for recovery as the undisturbed forest soil condition was more than 10 years in the road which was left, and the regression equation is as follows, $$Y_1=1.4195-0.0744{\cdot}X(R^2=0.91)$$ $$Y_2=1.4673-0.0688{\cdot}X(R^2=0.73)$$ (X : elapsed year after road construction. $Y_1$, $Y_2$ : soil bulk density($g/cm^3$) at 0~7.5cm, and 7.5~15.0cm, respectively) Especially soil bulk density with buffer strip-woods was $0.890-0.903g/cm^3$, so it was 20% lower than that of logging road surface without buffer strip-woods. Among the 7 factors, location, sand content, and soil hardness had statistically significant effect on the soil bulk density in logging road surface. The pioneer species on logging road surface were Rhus cratargifolius, Prunus chinensis, and Lespedeza cyrtobotrya, etc. in woody species, and Pteridium aquilinum, Arundinella hirta, and Lysimachia clethroides, etc. in herb species. So, in process of year, average plant coverage were 70% on cutting and banking slope and 20% on logging road surface which elapsed 6 years after logging road construction. Through this research, buffer strip-woods must be remained for environmental conservation of forest conditions, and from the time to be closed the road, planting, seeding, and grazing works could be effective to the soil condition and vegetation recovery.