• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.5
• /
• pp.589-598
• /
• 1995

Filtering rates of Crassostrea gigas were experimentally investigated with reference to effects of water temperature and size. Absorptiometric determinations of filtering rates with oysters being fed diatom Chaetoceros calcirtans were carried out in a closed system. Optical density of 675nm in path length 100mm cell used as the indication of food particles absorption was appeared directly In proportion with the concentration of diatom pigment $chlorophyll-\alpha$. In the closed system where $C_0$ is $OD_{675}$ at initial time 0, $C_t$, at time t, and Z is the decreasing coefficient of OD as meaning of instantaneous removal speed, then $C_t=C_0{\cdot} e^{-2t}$, $Z=In(C_t/C_0)/t$. On the assumption that the filtering rate is constant, then removal rate per unit time (d) is $d=-e^{-z}$. If t is used to time unit of hour (hr), the filtering rate (FR) in I/hr is given by $FR=V{\cdot}d=V(1-e^{-z})$, where V is the water volume (I) of the experimental vessel. Filtering rate increased as exponential function with increasing temperature while not over critical limit. The critical temperature for filtering rate was assumed to be between $28^{\circ}C$ and $29^{\circ}C$. And the weight exponent for filtering rate is 0.223. The model formula derived from the results as FR, $Ihr^{-1}$ = $Exp(0.208{\cdot}T-4.324){\cdot} (DW)^{0.223}$ (T<29 $^{\circ}C)$ where T is water temperature $(^{\circ}C

• International Journal of Industrial Entomology and Biomaterials
• /
• v.10 no.1
• /
• pp.45-49
• /
• 2005

Respiration in Antheraea mylitta was studied using constant pressure respirometer. Oxygen uptake in different stages of life showed that moth has highest rate of oxygen uptake as compared to larva and pupa. At each stage significant sexual differentiation was observed. Depression in the rate of oxygen uptake in diapausing pupa was found to be higher in male ($65.75\%$) than female ($60.65\%$) as compared to non-diapausing counterparts. During diapause lowest oxygen uptake was recorded in the month of February, and were in the order of February < January < December < March < November < April < May < June in male, and, February < January < December < March < April < November < May < June in female. Significant sexual differentiation in oxygen uptake was recorded throughout the period of diapause (November to June) where female pupae registered lower rate of oxygen uptake than that of male. Oxygen uptake in female pupae declined upto $28.89\%$ in non-diapausing and $18.29\%$ in diapausing broods over male. Highest respiratory quotient value was recorded in the moth of November (0.68 in male and 0.70 in female) and, the lowest in the month of March in male (0.54) and May in female (0.55). Percentage loss in pupa weight always remained at a significantly higher level in male (except in February and March). The lowest oxygen uptake rate and weight loss in the month of February shows that the pupae were at peak of their dormancy during this month.

• Journal of Ginseng Research
• /
• v.23 no.3 s.55
• /
• pp.172-175
• /
• 1999

The effect of Korean red ginseng extract on the pharmacokinetics of ethanol was examined in 14 male rats and 10 healthy male volunteers. Aqueous red ginseng extract (200 mg/kg), or an equivalent volume of water was administered orally to the rats and followed immediately by treatment with $50\%$ (v/v) ethanol orally (3.2 g/kg). The area under the curve (AVC) and elimination rate constant (Ke) of ethanol were $29.2{\pm}6.2\;g{\cdot}min{\cdot}dl^{-},\;0.51{\pm}0.06\;mg{\cdot}dl^{-}{\cdot}min.^{-}$ in ginseng-treated group and $28.0{\pm}5.6\;g{\cdot}min.{\cdot}dl^{-},0.5{\pm}0.1\;mg{\cdot}dl^{-}{\cdot}min.^{-}$ in control group. These differences were not significant. The volunteers were given orally with 3g of aqueous ginseng, or an equivalent volume of water, followed immediately by Korean alcoholic beverage, Soju (2.4 ml/kg). The AUC and Ke of ethanol for volunteers were $10.6{\pm}2.0\;g{\cdot}min.{\cdot}dl^{-}$ and $0.21{\pm}0.05\;mg{\cdot}dl^{-}{\cdot}min.^{-}$ in ginseng-treated group and $11.0{\pm}2.2\;g{\cdot}min.{\cdot}dl^{-}$ and $0.22{\pm}0.04\;mg{\cdot}dl^{-}{\cdot}min.^{-}$ in control group. These differences were not also significant. These results suggest that an application of red ginseng extract does not have any clinically significant effect on the pharmacokinetics of ethanol.

• Journal of Bio-Environment Control
• /
• v.23 no.1
• /
• pp.39-42
• /
• 2014

The objective of this study was to estimate cardinal temperatures for germination of lettuce (Lactuca sativar L.) using bilinear, parabolic, and beta distribution functions. Seeds of lettuce were germinated in a growth chamber at 7 constant temperatures: 10, 14, 16, 20, 24, 28, and $32^{\circ}C$. Four replicates of 100 seeds were placed on two layers of filter paper in a 9 cm petri-dish. Radicle emergence of 1 mm was scored as germination. The time course of germination was modeled using a logistic function. These minimum, optimum, and maximum temperatures were estimated by regression of the inverse of time to 50% germination rate against the temperature gradient. In bilinear function, minimum, optimum, and maximum temperatures were $7.9^{\circ}C$, $23.3^{\circ}C$, and $28.0^{\circ}C$, respectively. In parabolic function, minimum, optimum, and maximum temperatures were $9.7^{\circ}C$, $19.5^{\circ}C$, and $29.4^{\circ}C$, respectively. In beta distribution function, minimum, optimum, and maximum temperatures were $3.7^{\circ}C$, $20.7^{\circ}C$ and $32.0^{\circ}C$, respectively. Minimum, optimum, and maximum ranges of temperatures were $3.7{\sim}9.7^{\circ}C$, $19.5{\sim}23.3^{\circ}C$, and $28.0{\sim}32.0^{\circ}C$, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.6C
• /
• pp.303-311
• /
• 2009

In this study, weakly cemented sand was cured at air dry condition with different periods (3, 7, 14, 21, 28 days) and its unconfined compressive strength was evaluated. As a result, the strength of specimens with low cement ratios such as 4 and 8% increases until 7 days curing but, after 7 days, their strength continuously decreases. The strength of specimens with relatively high cement ratios such as 12 and 16% increases up to 7 days curing and then stays almost constant until 21 days. After 21 days curing, their strength suddenly dropped down, which is much lower than the strength of 3 days curing specimen. A cemented sand and gravel called CSG, which is highly permeable, could be exposed to repetitive drying and wetting conditions due to rainfall or groundwater table change during curing. In this study, the weakly cemented sand is exposed to repetitive drying and wetting and then its unconfined compressive strength was evaluated. As a result, the strength of a specimen with 27 days drying condition following 1 day wetting was at maximum 35% lower than the one cured under 28 days drying. The strength degradation due to wetting decreases as a cement ratio increases. However, the strength of a specimen with repetitive drying and wetting increases as the number of wetting increases until 3 cycles. After 3 cycles of drying and wetting, the rate of strength increase decreases due to an insufficient water for hydration or stays constant. If the sufficient water supply is provided to cemented sand during curing, the target or design strength increase can be achieved. Otherwise, the strength degradation due to wetting should be considered at the design stage.

• Korean Journal of Community Nutrition
• /
• v.20 no.6
• /
• pp.468-478
• /
• 2015

Objectives: The objective of this study was to evaluate the thermic effects, the macronutrient oxidation rates and the satiety of medium-chain triglycerides (MCT). Methods: The thermic effects of two meals containing MCT or long-chain triglycerides (LCT) were compared in ten healthy men (mean age $24.4{\pm}2.9years$). Energy content of the meal was 30% of resting metabolic rate of each subject. Metabolic rate and macronutrient oxidation rate were measured before the meals and for 6 hours after the meals by indirect calorimetry. Satiety was estimated by using visual analogue scales (VAS) at 8 times (before the meal and for 6 hours after meal). Results: Total thermic effect of MCT meal (42.8 kcal, 8.0% of energy intake) was significantly higher than that (26.8 kcal, 5.1% of energy intake) of the LCT meal. Mean postprandial oxygen consumption was also significantly different between the two types of meals (MCT meal: $0.29{\pm}0.35L/min$, LCT meal: $0.28{\pm}0.27L/min$). There were no significant differences in total postprandial carbohydrate and fat oxidation rates between the two meals. However, from 30 to 120 minutes after consumption of meals, the fat oxidation rate of MCT meal was significantly higher than that of the LCT meal. Comparison of satiety values (hunger, fullness and appetite) between the two meals showed that MCT meal maintained satiety for a longer time than the LCT meal. Conclusions: This study showed the possibility that long-term substitution of MCT for LCT would produce weight loss if energy intake remained constant.

• Journal of Sericultural and Entomological Science
• /
• v.29 no.1
• /
• pp.1-6
• /
• 1987

Changes in water content, dry weight, total nitrogen (T-N), P, K, Ca, Mg, B, Fe, Cu, Zn and Mn and death rate were studied in winter buds of mulberry trees. Winter buds of the early season varieties, Hongolbbong and Chongolbbong, (Morus Lhou Koioz) and midseason varieties, Kaeryangbbong and Chongilbbong, (Morus alba L.) were sampled every 7 days from February 28 to April 28, 1986. The result were as follow : 1. Water content was increased by 20% over the level of 45% in late February. The water content in Chongolbbing was the highest, whereas that in the rest of the varieties was nearly equal. 2. Dry weights of winter buds of the early varieties were always greater than those of midseason varieties. The dry weight of buds of early season varieties began to increase in late February and increased rapidly after April 18. There was no weight gain until April 12 in buds of midseason varieties, followed by a slow increase thereafter. 3. T-N and P, K, B, Fe, Cu and Zn concentration increased with time, Mn decreased, and Ca and Mg levels were constant. 4. T-N and Mn levels were higher and P, Ca, Fe and Cu lower in Hongolbbong than in the other varieties. T-N, Mg and Cu levels were lower in Chongolbbong. 5. The death rate of winter buds increased with the approach of the budding season. The rate was highest in Chongolbbong and lowest in Hongolbbong.

• Korean Journal of Soil Science and Fertilizer
• /
• v.50 no.5
• /
• pp.325-335
• /
• 2017

This study was carried out for 30 days in aeration type and agitation type reactor to characterize organic matter decomposition and ammonia volatilization during the liquid composting of pig slurry, and organic matter and nitrogen removal rate through mass balance analysis was analyzed. In the aeration type reactor, the pH increased from 7.0 to 9.13, and TS 34.5%, VS 33.4%, $BOD_5$ 71.2%, $COD_{Cr}$ 62.3% and TOC 83.2% were removed. In addition, 44.6% of TN and 65.0% of ${NH_4}^+-N$ were removed. In the agitation type reactor, the pH increased from 7.0 to 8.10, and the removal rates of TS 0.9%, VS 0.5%, $COD_{Cr}$ 27.5%, $BOD_5$ 28.9% and TOC 41.3% were obtained. And TN and ${NH_4}^+-N$ showed removal rate of 25.3% and 29.2%, respectively. The first order kinetics constant related to $BOD_5$ degradation was $-0.039day^{-1}$ for aerobic liquid composting and $-0.013day^{-1}$ for agitated reactor. Nitrogen loss in aerobic liquid composting was about 2.3 times higher than that of agitated reactor, whereas FAN/TAN in aerobic liquid composting was about 7.9 times higher than that of agitation type reactor. Therefore, despite the low FAN/TAN in the agitation type reactor, the nitrogen loss rate was relatively high.

• Korean journal of applied entomology
• /
• v.61 no.3
• /
• pp.435-447
• /
• 2022

The soybean podborer, Matsumuraeses falcana (Lepidoptera: Tortricidae), is one of important pests in soybean crop. In the purpose of forecasting population dynamics of M. falcana, we investigated the effects of temperature on development of each life stage, adult longevity and fecundity of Matsumuraeses falcana at seven constant temperatures of 10, 13, 19, 22, 25, 28, and 31℃. Eggs hatched successfully at all temperature subjected. M. falcana developed from egg hatching to adult emergence at the tested temperatures except 10, 13, and 31℃. The developmental period of each life stage and adult longevity of M. falcana decreased as temperature increased. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of M. falcana were estimated by linear regression as 10.2℃ and 492.04DD, respectively. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. TL and TH from egg hatching to adult emergence using SSI model were 16.7℃ and 29.1℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of M. falcana was 12.4℃. We constructed the adult oviposition model of M. falcana using adult survivorship and fecundity. Temperature-dependent immature development and adult oviposition models will help constructing the population model of M. falcana and developing the strategies of integrated pest management in soybean fields.

• Korean Journal of Food Science and Technology
• /
• v.29 no.5
• /
• pp.939-946
• /
• 1997

Effects of moisture content on the gelatinization and recrystallization of non-waxy and waxy rice starch gels were investigated by differential scanning calorimetry (DSC). The recrystallization rates of the starch gels containing various moisture contents $(40{\sim}70%)$ were analyzed by Avrami equation. The waxy rice starch had higher gelatinization temperature and enthalpy than non-waxy one. The highest degrees of recrystallization in both rice starch gels stored at $4^{\circ}C$ were shown at 40%, and recrystallizations above 80% moisture content were not found. The degree of recrystallization of waxy one was higher than that of non-waxy one in the range of 40 to 60% moisture content. The Avrami exponents (n) of both rice starch gels were near to 1.0 and the time constant (1/k) was increased with increasing moisture content in the range of 40 to 70% moisture content. The recrystallization rate of waxy rice starch gel was slower than that of non-waxy one. The recrystallization of rice starch gels could be explained by the change of ice melting enthalpy during storage. The Wg's, represented the maximum practical amount of plasticizing water, were about 29.9% and 28.2% for non-waxy and waxy rice starch gels, respectively.