• Journal of Bio-Environment Control
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• v.23 no.3
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• pp.199-204
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• 2014

This study evaluated the effect of water content in the substrate during pre- and post-grafting period on the survival rate and quality of tomato plug seedlings. Nine combinations of three water levels (high, medium, and low) were set up in the substrate of both scion and rootstock. The water content in the substrate of the scion did not affect the survival rate of grafted tomato seedlings, while the survival rate was statically different among the various water contents in the substrate of the rootstock. The maximum survival rates (100%) were observed in seedlings treated with high water levels in the substrate of the rootstock, and the survival rates declined with decreasing water content in the rootstock substrate. The growth characteristics were not significantly affected by different water content in the scion substrate, while they were statically different among the seedlings treated with various water contents in the rootstock substrate. The growth characteristics decreased with decreasing water content in the rootstock substrate. The highest value of compactness was observed in grafted seedlings, which combined medium water level in the scion and high water level in the rootstock substrate treatment. The root morphology of tomato seedlings was also affected by water content in the rootstock substrate. The total root surface area, total root length, and number of root tips decreased with deceasing water content in the rootstock substrate.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.41-42
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• 2001

The objectives of this study were to investigate the effect of the physical properties of wick on the water absorption of substrate. Physical properties of wick in this study were cotton composition, width and length. The water Infiltration rate through the wick was 0.24 ㎝/s at 90 -95% cotton content, which was faster than at 80-85% (0.13 cm/s) and 70-75% (0.08 cm/s). As the cotton content increased, the water absorption of substrate became greater : the amount of absorbed water was about 5-7g higher at 90-95% than at 80-85% and 70-75% at a wick width of 1 ㎝, the velocity of water absorption through the wick was fastest with 0.25 ㎝ㆍs/sup -1/. The amount of absorbed water was higher at 3 ㎝ than at 1 and 2 ㎝. However, the water absorption rate through the cross - sectional area of wick (g H₂O /㎠/hr) was higher at a wick width of 2 ㎝ than at those of 1 and 3 ㎝. The amount of absorbed water in the substrate was higher at 2 : 1 than at 1 : 1 (length in substrate : length out of substrate). Absorbed water amount was larger at 30-40% initial moisture content than any other treatment.

• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.27-36
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• 2021

A capacitive water sensor was developed to measure the capacitance over a wide part of a substrate using an insulated electrode plate (30 cm × 10 cm) with copper and Teflon attached on either side of the substrate. This study aimed to convert the capacitance output obtained from the condenser-type capacitance sensor into the substrate water content. The quantification experiment was performed by measuring the changes in substrate water weight and capacitance while providing a nutrient solution and by subsequently comparing these values. The substrate water weight and capacitance were measured every 20 to 30 seconds using the sensor and load cell with a software developed specifically for this study. Using a curve-fitting program, the substrate water content was estimated from the output of the capacitance using the water weight and capacitance of the substrate as variables. When the amount of water supplied was increased, the capacitance tended to increase. Coefficient of variation (CV) in capacitance according to the water weight in substrate was greater with the 1.0 kg of water weight, compared with other weights. Thus, the fitting was performed with higher than 1.0 kg, from 1.7 to 6.0 kg of water weight. The correlation coefficient between the capacitance and water weight in substrate was 0.9696. The calibration equation estimated water content from the capacitance, and it was compared with the substrate water weight measured by the load cell.

• Journal of Life Science
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• v.5 no.4
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• pp.155-161
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• 1995

The effects of substrate concentration, enzyme concentration, reaction temperature, and water content were investigated in intramolecular esterification. This study used cyclohexane as organic solvent, power lipase as enzyme, and benzyl alcohol and octanoic acid as substrate. The initial reaction rate was found to be proportional to enzyme concentration; followed Michaelis-Menten equation for octanoic acid; and was inhibited by benzyl alcohol . The observed initial reaction rate first increased, then decreased with increasing reaction temperature, giving rise to the maximum rate at 20$\circ$. The drop in the reaction rate at higher temperature was to partition equilibrium change of substrate between organic solvent and hydration layer of enzyme molecule in addition to the deactivation by enzyme denaturation. Water layer surrounding enzyme molecule seemed to activate in organic solvent and the realistic reaction was done in the water layer. In the enzymatic reaction in organic solvent, the initial reaction rate was influenced by partition quilibrium of substrate, so the optimum condition of substrate concentration, enzyme concentration, reaction temperature, and water content would give a good design tool.

• Journal of the Korean Wood Science and Technology
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• v.28 no.1
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• pp.65-70
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• 2000

Ergosterol is an indicator chemical of fungi and involves in fungal cell growth as a major component in fungal cell membranes. Thus, this chemical can be used to estimate live fungal biomass within various solid substrates. Ergosterol content in liquid culture of Lentinula edodes had a linear relationship (r=0.98) with the hyphal mass of the fungus. This chemical content differed depending on the fungal strains, age of culture and water content levels of sawdust substrate. Ergosterol content was 0.13% in the 10 weeks old liquid culture while it was 0.10% in 20 weeks old one. The chemical content in the sawdust cultures of the fungus varied 0.015% to 0.042% depending upon strains and water content levels within sawdust substrate. Ergosterol content in the culture of a L. edodes strain, Sanrim 4, was higher by $20{\mu}g$ to $140{\mu}g$/g dry substrate than those of strains, Mok-H and Sanrim 6. And the chemical contents in the sawdust cultures with 125% or 175% water, 297 to 425 ${\mu}g$/g dry substrate, were higher than those with 75% or 225% water, 148 to $286{\mu}g$/g dry substrate. We conclude that ergosterol analysis can estimate the fungal biomass within solid substrate such as logs and sawdust.

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.88-94
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• 2001

Physical and chemical properties, the salt accumulation and leaching of salt by water of coal fly ash ball (ash ball) were evaluated in comparison with perlite and granule rockwool (rockwool). Bulk density, particle density, solid phase, and porosity of ash ball were 0.93 g.cm$^{-3}$ , 2.29 g.cm$^{-3}$ , 40.6%, 59.4%, respectively. The bulk density of ash ball was greater, while porosity was smaller, than that of perlite and rockwool. Saturation moisture capacity was 52% in ash ball, 71% in perlite, and 90% in rockwool. Water contents after drainage for 1 hr of ash ball, perlite, and rockwool were 21%, 27%, and 80%, respectively. Water content of small granules (3-5 mm) of ash ball was 5% greater than that of large (7-15 mm) grannules. The ash ball was a weak alkali substrate with pH 7.6, but not electric conductivity (EC), of the nutrient solution supplied to ash ball slightly increased. When the absorption of mineral ions to substrates were analyzed, ash ball and RW absorbed mainly PO￣$_4$. On tomato culture, salt accumulation in ash ball substrate was similar to that in perlite. Most of the salts in the ash balls were removed by submerging the substrate eight times in distilled water. It is concluded that water holding capacity of ash ball substrate was lo as compared to other substrates, but air permeability, and water diffusion was excellent, making control of medium water content easy.

• Journal of Bio-Environment Control
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• v.9 no.1
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• pp.20-26
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• 2000

This study aims at analyzing physical and chemical properties of perlite substrate. Particles of substrate were divided into five categories In size: gravel, very-coarse, coarse, medium and fine grade. Particles of very-coarse and greater grades in perlite substrate occupied 98.5％ of total particles. The air phase of total particles was distributed between 76.8％ and 87.7％ with especially showing that of very-coarse grade was lower than that of coarse or smaller one. However, the liquid and solid phases were vice versa. The cation exchange capacity (CEC) measured was highest in the fine grade. In drainage experiments, the water being drained from the substrate increased with the ratio of drain area, and the 65~70％ of total water reduced within five minutes after irrigation. The drained volume was proportional to the depth of the substrate, which contained about 2mL.cm$^2$：by depth (cm). Due to quick reduction of the water in the substrate, the pF value increased in four minutes after irrigation and showed the highest negative correlation ($R^2$＝0.997) with the moisture content of the substrate. The physical and chemical properties including drainage characteristics analyzed in this study can be, therefore, utilized to control the moisture content of perlite substrate, efficiently.

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.167-172
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• 2006

The objective of this study was to determine the effects of substrate water content and electrical conductivity (EC) on the incidence of brown fruit stem and blossom end rot in glasshouse sweet pepper (Capsicum annuum cv. Special). Three levels of water content and EC had been treated since the first fruit reached 3cm in diameter: that is, 49 (low), 65 (medium), and 86% (high) for water content, and 2.4 (low), 4.2 (medium) and $6.3dS{\cdot}m^{-1}$(high) for EC. Shoot growth was reduced with decreasing water content, and it was lower in both high and low EC treatments than medium EC treatment. Fruit weight at harvest was greater in both medium and hish water content treatments than low water content treatment (158g vs 146g). High EC reduced fruit weight compared to or low EC treatments. The incidence of brown fruit stem increased with increasing water content and with decreasing EC. The highest incidence was shown in the high water content/low EC treatment (38%), which was considerably higher than 2.4% of the low water content/high EC treatment. Blossom end rot occurred in general in the low water content and/or high EC conditions. These results indicated that substrate water content and EC should be controlled differently according to the growth stage, to reduce the incidence of blossom end rot and brown fruit stem in glasshouse sweet pepper. First, to reduce blossom end rot incidence, water content should be maintained high (86%) and EC low ($2.4dS{\cdot}m^{-1}$) until Sweets after fruit set. Secondly, to reduce brown fruit stem incidence, water content should be maintained low (49%) and EC high ($6.3dS{\cdot}m^{-1}$), especially after completion of fruit growth.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.14 no.1
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• pp.47-58
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• 2003

Brown rice was used as material for solid-substrate cultivation of Ganoderma lucidum. The hydration time with cold water appeared to be 10 hours for brown rice, but the final water content was much less than optimum water content(65%). Hot water reduced the hydration time of brown rice, and the water content reached to 65% within 40 mins. From this result, hot water was better than cold water for the hydration of brown rice. We attempted to develop a practically applicable process by combining the soaking and sterilization. The water content of 65% appeared to be the best for the growth of the fungi and production of glucosamine related to the amount of mycelium. The content of free sugar increased far more in brown rice fermented with mycelium than in brown rice which was not fermented. Addition was most suitable 20% when add mushroom-rice to brown rice.

• The Korean Journal of Mycology
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• v.24 no.1 s.76
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• pp.81-88
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• 1996

Cereals were used as solid-substrate for the cultivation of Ganoderma lucidum. The hydration time with cold water appeared to be 10, 11 and 12 hours for Malt, Danyeob and Black soybeans respectively, and the water content was enough for mycelial growth in this condition. The hydration times required for sorghum, job's tears, barley, brown rice and wheat were 2.5, 4, 5, 10 and 12 hours respectively, but the final water content was much less than optimum water content (65%). Hot water reduced the hydration time of soybeans, and the water content reached to 65% within $120{\sim}150$mins. This condition showed the optimum for the mycelial growth. For the other cereals, it took about $17{\sim}120$ mins to reach the optimum water content (65%). From this result, hot water was better than cold water for the hydration of cereals. We attempted to develop a practically applicable process by combining the soaking and sterilization. This process was successful with soybean and about 1.1 times of water based on the weight of soybean appeared to be suitable. In all varieties of cereal, the water content of 65% appeared to be the best for the growth of the fungi and production of glucosamine related to the amount of mycelium. The mycelial growth rate in accordance with kinds of solid-state materials was in the order of barley > wheat > job's tears > sorghum > brown rice > soybean. The glucosamine content for determing the mycelial growth in solid material was in the order of wheat> barley > brown rice > job's tears > sorghum > soybean.