• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.386-408
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• 1988

A study was conducted to develop a model for estimating evapotranspiration and yield of Chinese cabbages from meteorological factors from 1981 to 1986 in Suweon, Korea. Lysimeters with water table maintained at 50cm depth were used to measure the potential evapotranspiration and the maximum evapotranspiration in situ. The actual evapotranspiration and the yield were measured in the field plots irrigated with different soil moisture regimes of -0.2, -0.5, and -1.0 bars, respectively. The soil water content throughout the profile was monitored by a neutron moisture depth gauge and the soil water potentials were measured using gypsum block and tensiometer. The fresh weight of Chinese cabbages at harvest was measured as yield. The data collected in situ were analyzed to obtain parameters related to modeling. The results were summarized as followings: 1. The 5-year mean of potential evapotranspiration (PET) gradually increased from 2.38 mm/day in early April to 3.98 mm/day in mid-June, and thereafter, decreased to 1.06 mm/day in mid-November. The estimated PET by Penman, Radiation or Blanney-Criddle methods were overestimated in comparison with the measured PET, while those by Pan-evaporation method were underestimated. The correlation between the estimated and the measured PET, however, showed high significance except for July and August by Blanney-Criddle method, which implied that the coefficients should be adjusted to the Korean conditions. 2. The meteorological factors which showed hgih correlation with the measured PET were temperature, vapour pressure deficit, sunshine hours, solar radiation and pan-evaporation. Several multiple regression equations using meteorological factors were formulated to estimate PET. The equation with pan-evaporation (Eo) was the simplest but highly accurate. PET = 0.712 + 0.705Eo 3. The crop coefficient of Chinese cabbages (Kc), the ratio of the maximum evapotranspiration (ETm) to PET, ranged from 0.5 to 0.7 at early growth stage and from 0.9 to 1.2 at mid and late growth stages. The regression equation with respect to the growth progress degree (G), ranging from 0.0 at transplanting day to 1.0 at the harvesting day, were: $$Kc=0.598+0.959G-0.501G^2$$ for spring cabbages $$Kc=0.402+1.887G-1.432G^2$$ for autumn cabbages 4. The soil factor (Kf), the ratio of the actual evapotranspiration to the maximum evapotranspiration, showed 1.0 when the available soil water fraction (f) was higher than a threshold value (fp) and decreased linearly with decreasing f below fp. The relationships were: Kf=1.0 for $$f{\geq}fp$$ Kf=a+bf for f$$I{\leq}Esm$$ Es = Esm for I > Esm 6. The model for estimating actual evapotranspiration (ETa) was based on the water balance neglecting capillary rise as: ETa=PET. Kc. Kf+Es 7. The model for estimating relative yield (Y/Ym) was selected among the regression equations with the measured ETa as: Y/Ym=a+bln(ETa) The coefficients and b were 0.07 and 0.73 for spring Chinese cabbages and 0.37 and 0.66 for autumn Chinese cabbages, respectively. 8. The estimated ETa and Y/Ym were compared with the measured values to verify the model established above. The estimated ETa showed disparities within 0.29mm/day for spring Chinese cabbages and 0.19mm/day for autumn Chinese cabbages. The average deviation of the estimated relative yield were 0.14 and 0.09, respectively. 9. The deviations between the estimated values by the model and the actual values obtained from three cropping field experiments after the completion of the model calibration were within reasonable confidence range. Therefore, this model was validated to be used in practical purpose.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.79-87
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• 2008

Many researchers have studied on rooftop greening that can be installed in abandoned spaces on a building roof. The most important issue in rooftop greening is the soil weight problem. The light greening materials are needed to solve this problem. Therefore, many alternative materials against the soil were investigated for rooftop greening. In this study, the waste wood chips and the waste paper slurry were evaluated as the lightweight vegetation foundation for rooftop greening. It also has a meaning for recycling of waste materials. The mixture ratio of waste wood chips to waste paper slurry for the board (the foundation of greening) was 60 to 40. The wet strength resin and the sizing agent were additionally added with different amount. After the forming of the board, physical and chemical properties were tested with the variation of wet strength resin and sizing agent. As the result of the test, the board with 15% of wet strength resin in the wet condition showed the highest strength. Futhermore, the moisture evaporation loss from the board surface with sizing agent was much lower than that from the board without sizing agent. Therefore, it was clear that the sizing agent was effective for water retention. The change of thickness in the wet condition was less than 1 mm, and it showed that the board is the predominant material on the dimensional stability. The average pH value of the board was ranged from 7.6 to 8.25.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.426-434
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• 2009

This study was carried out to derive the most optimal production process for the wood fuels(chip and pellet), by collecting cost data on each procedure through the life cycle assessment approach, and to compare between the profitability and efficiency, from the view points of producers and consumers, irrespectively. The costs accounted in this analysis were based on the opportunity cost. The results show that wood chips are cheaper than wood pellets in production costs. In respect to the process with the lowest production cost, while wood chips should be to crush collected residues into pieces on the spot for merchandizing, wood pellets need to be transported to manufactory for pelletizing. The study findings also include that the profits, which is estimated by subtracting expenses from gained sale revenue, were a bit higher for wood chips than wood pellets. Additionally, the price ratio of wood pellets to wood chips for getting the same caloric value appears to be 1.27. Despite of economic benefits of processing wood chips, there are several problems in practice. For producers, there is a possible increase in not only transportation cost for conveying crushers to the dispersed places, but storage cost due to the lack of the marketplaces in the immediate surroundings. For consumers, on the other hand, there are some challenging issues, such as bulky storage facility requirement, additional labor for fuel supplement, frequent ashes disposal, and decomposition in summer and freezing in winter caused by wood chips' own moisture.

• Culinary science and hospitality research
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• v.22 no.3
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• pp.55-65
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• 2016

The purpose of this study was to determine the most appropriate ratio for burdock glutinous rice Dasik. Burdock glutinous rice Dasik was prepared with different levels of burdock powder (0, 3, 6, 9 and 12%) and the quality characteristics of burdock glutinous rice Dasik were analyzed. Moisture contents of burdock glutinous rice Dasik increased as the amount of burdock powder increased (p<0.001) compared to the control group. The L-value, a-value, and b-value of burdock glutinous rice Dasik showed a tendency to decrease compared to the control group. The sugar content of burdock glutinous rice Dasik increased (p<0.001) with the amount of burdock powder. The hardness and adhesiveness of the glutinous rice Dasik with burdock powder of 6% or less were decreased, but those with 9% or more burdock powder had higher hardness and adhesiveness than the control group. In addition, the cohesiveness, springiness, gumminess, and chewiness of glutinous rice Dasik with burdock powder increased compared to the control group. The DPPH free radical scavenging activity of the glutinous rice Dasik with 9% and 12% burdock powder were higher than that of the control group (p<0.001). In the sensory test of burdock glutinous rice Dasik, the samples added with 3% and 6% burdock powder gained higher preferences, but the evaluations of others were lower than that of the control group. The glutinous rice Dasik with less than 6% burdock powder was highly evaluated, so it is considered as the most appropriate sample.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.174-179
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• 2015

This experiment was conducted to determine the optimal harvesting time for barley and wheat grain for the production of fermented grain feeds, and to investigate their fermentation quality according to harvesting time. As a result, grain moisture content was decreased with late harvest, whereas spike weight ratio and 1000 grain weight were increased with prolonged period after heading. Grain yielding was increased with late harvesting time significantly at p<0.05. Crude protein content was increased with late harvesting time, but crude fiber content was decreased. Crude fat and ash content were slightly decreased, but not statistically significant. Comparing the effects of fermentation on feed value of winter cereal grain, the approximate compositions were slightly increased after fermentation, but the difference was not significant. Fermentations resulted in increasing the pH value of winter cereal grain silage with late harvesting time, but decreasing the lactic acid content (p<0.05). No significant difference was found in acetic acid, and butyric acid was not detected. Considering the quantity and quality of fermentation, barley and wheat can be used for winter cereal grain silage when they were harvested at 35 days and 40-45 days after heading, respectively.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.42-46
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• 1984

This study was carried out to obtain the advanced basic data for hillside erosion control works. Recovery of vegetation in the hillside erosion control districts depends on various factors i.e., topographies, soil qualities, rain conditions and erosion control methods. The only relations between topographies and vegetation coverage were surveyed, since the other factors were equal in all those surveyed areas. The results obtained are summarized as follows; 1) Mean coverage values were decreased in order of 80%, 78.7%, 64.0% and 56.5%r in concave slope, uniform slope, compound slope and convex slope respectively. The mean coverage of all aspects was 69.8%. The slope pattern have a influence on formation of coverage. 2) Moisture ratio in soil and mean slope have an effect on the mean coverage value. 3) In the beginning of the hillside erosion control working, coverage (14.8%) by arbor species was too low comparing with that by herb. 4) It is more desirable to recover regetation by artificial planting or seed planting than by the natural vegetation in the barren hillside. In the beginning of the hillside erosion control working, it is difficult to expect vegetation recovery by natural species.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.532-539
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• 2012

Electron spin resonance (ESR) spectroscopy of gamma-irradiated fresh broccoli and kimchi cabbage was conducted to identify their irradiation history. Different pretreatments, such as freeze-drying (FD), oven-drying (OD), alcoholic-drying (ALD), and water-washing and alcoholic-drying (WAD) were used to lower the moisture contents of the samples prior to ESR analysis. The non-irradiated samples exhibited a single central signal ($g_0$=2.0007) with clear effect of $Mn^{2+}$, especially in kimchi cabbage. Upon irradiation, there was an increase in the intensity of the central signal, and two side peaks, mutually spaced at 6 mT, were also observed. These side peaks with $g_1$ (left)=2.023 and $g_2$ (right)=1.985 were attributed to radiation-induced cellulose radicals. Leaf and stem in broccoli, and root and stem in kimchi cabbage provided good ESR signal responses upon irradiation. The signal noise was reduced in case of ALD and WAD pretreatments, particularly due to $Mn^{2+}$ signals. The ALD treatment was found most feasible to detect the improved ESR spectra in the irradiated samples.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.159-164
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• 2016

This study was conducted to investigate the quality characteristics and antioxidant properties of cookies supplemented with 1-4% (w/w) persimmon leaf powder (PLP). pH and density of the cookie dough increased significantly with increase in PLP concentration (p<0.05). The moisture content, spread ratio, and loss rate of cookies decreased significantly with increase in PLP concentration (p<0.05). Lightness ($L^*$), redness ($a^*$), and yellowness ($b^*$) also decreased significantly with increase in PLP concentration (p<0.05). The use of PLP significantly increased the hardness of the cookies. Moreover, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities were significantly elevated (p<0.05). The consumer acceptance test indicated that addition of PLP at a concentration of up to 2% (w/w) garnered a favorable response from consumers with respect to softness, taste, and overall preference. On the basis of the overall observations, cookies supplemented with 2% (w/w) PLP were found to benefit from the functional properties of PLP, without compromising on consumer acceptance.

• Food Science and Preservation
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• v.21 no.6
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• pp.824-830
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• 2014

In this study, the quality characteristics of cookies with added purple kohlrabi (Brassica oleracea var. gongylodes) powder were investigated and analyzed through chemical and sensory evaluation. Samples were prepared with different levels (0, 1, 3, and 5%) of freeze-dried kohlrabi powder. The addition of Kolarbi powder decreased the moisture and fat contents, but the ash content was significantly increased (p<0.05). The pH and density of the cookie dough decreased significantly with the increasing levels of kohlrabi powder added (p<0.05). The spread ratio of the cookies generally decreased as more kohlrabi powder was added, but the decrease was not statistically significant. The hardness of the cookies increased significantly, however, with the increasing levels of kohlrabi powder added (p<0.05). The Hunter's color L, a, and b values significantly decreased with increasing kohlrabi powder compared to those of the control (p<0.05). In the sensory evaluation, the cookies to which 3 and 5% kohlrabi powder were added showed remarkably higher values for color, taste and appearance. These results suggest that purple kohlrabi powder is a good ingredient for improving the sensory and quality characteristics of cookies.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.3-12
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• 2006

The behavior of concrete structures subject to fire is complex, depending on many factors. The factors usually considered in research include the level and endurance of temperatures in concrete and reinforcing bars, the mechanical properties of the steel and concrete, moisture contents, cover thickness, existence of eccentricity, and member geometry among others. Although there are a few sophisticated numerical models which can trace the effects of these important parameters on the residual capacity of reinforced concrete columns damaged by fire, practical predictive formulas are in need for rapid yet reasonable assessment in practice. The practical formulas are developed in this study for fire-damaged normal strength reinforced concrete square columns, which can approximate the predictions of those sophisticated numerical models with ease in use. The formulas take into account the effects of exposure time to fire, concrete strength, reinforcement ratio and sectional area. The developed formulas are seen to correlate with the predictions of numerical model in a reasonable agreement. Some examples are also presented in determining the residual strength, safety and additionally needed strengths for a fire-damaged reinforced concrete column.