• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1273-1276
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• 1999

Several reports have indicated that a rectal temperature of buffaloes is easily influenced by their surroundings. To clarify an effect of changing environmental temperature on thermoregulatory responses of buffaloes, an environment with diurnal temperature changes of $25^{\circ}C$ to $35^{\circ}C$ was created using an artificial climate laboratory. Three swamp buffaloes and three Friesian cows were exposed to three different experimental periods as follows: Period 1 (constant temperature of $30^{\circ}C$, Period 2 (diurnally changing temperature) and Period 3 (diurnally changing temperature and fasting). Heat production, rectal temperature, respiration rate, heart rate and respiration volume were measured during each period. Rectal temperature of the buffaloes fluctuated diurnally with the changing temperature (Periods 2 and 3), but remained constant in cows. Mean heat production was significantly lower in buffaloes than in cows in Period 2 and 3. However, the maximum rectal temperature and the increment of heat production were not always lower in buffaloes than in cows during Period 2. These results show that a rectal temperature and heat production in buffaloes are markedly influenced by the diurnal changes in temperature. Compared with Bos Taurus cows, the differences may be attributed to the physiological features of buffaloes including a high heat conductivity of their bodies and an lower heat production.

• Applied Biological Chemistry
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• v.17 no.1
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• pp.42-48
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• 1974

Hot air thin layer drying method was studied for red pepper, Capsicum annum var. longum as the whole and cut pod states, at various temperature and air velocities. Drying curve of whole pod showed a settling down period followed by the first and second falling rate periods. By lowering the drying temperature, the first falling rate period approached to a constant rate one. Cut drying curve had simple falling rate period and also cut drying method could effectively shorten the drying time. Drying rate constant, k, was varied with time for both the drying methods and the plots of k vs. time in two methods sugested the different drying mechanisms. When an average k was taken as a constant value, the following equations; $M-M_e/M_o-M_e=e^{-0.118t}$ and $M-M_e/M_o-M_e=e(-0.342t^{0.128})$ were applicable for whole and cut drying, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.411-418
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• 2019

In this study, to investigate the effect of physical and chemical properties of butanol on the engine performance and combustion characteristics, the coefficient of variations of IMEP (indicated mean effective pressure) and fuel conversion efficiency were obtained by measuring the combustion pressure and the fuel consumption quantity according to the engine load and the mixing ratio of diesel oil and butanol. In addition, the combustion pressure was analyzed to obtain the pressure increasing rate and heat release rate, and then the combustion temperature was calculated using a single zone combustion model. The experimental and analysis results of butanol blending oil were compared with the those of diesel oil under the similar operation conditions to determine the performance of the engine and combustion characteristics. As a result, the combustion stabilities of D.O. and butanol blending oil were good in this experimental range, and the indicated fuel conversion efficiency of butanol blending oil was slightly higher at low load but that of D.O. was higher above medium load. The premixed combustion period of D.O. was almost constant regardless of the load. As the load was lower and the butanol blending ratio was higher, the premixed combustion period of butanol blending oil was longer and the premixed combustion period was almost constant at high load regardless of butanol blending ratio. The average heat release rate was higher with increasing loads; especially as butanol blending ratio was increased at high load, the average heat release rate of butanol blending oil was higher than that of D.O. In addition, the calculated maximum. combustion temperature of butanol blending oil was higher than that of D.O. at all loads.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.183-192
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• 2002

Indoor air quality is affected by source strength of pollutants, ventilation rate, decay rate, outdoor level and so on. Although technologies exist to measure these factors directly, direct measurements of all factors are impractical in most field studies. The purpose of this study was to develop an alternative methods to estimate these factors by multiple measurements. Daily indoor and outdoor NO$_2$concentrations for 21 days in 20 houses in summer and winter, Seoul. Using a mass balance model and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor(emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the ventilation and source strength were estimated. During sampling period, geometric mean of natural ventilation was estimated to be 1.10$\pm$1.53 ACH, assuming a residential NO$_2$decay rate of 0.8 hr$^{-1}$ in summer. In winter, natural ventilation was 0.75$\pm$1.31 ACH. And mean source strengths in summer and winter were 14.8ppb/hr and 22.4ppb/hr, respectively. Although the method showed similar finding previous studies, the study did not measure ACH or the source strength of the house directly. As validation of natural ventilations, infiltrations were measured with $CO_2$tracer gas in 18 houses. Relationship between ventilation and infiltration was statistically correlated (Pearson r=0.63, p=0.02).

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.1046-1053
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• 1999

The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.304-311
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• 2009

This article proposes a new time-based depreciation method using the accumulated depreciation rate function. The method can systematically compute the depreciation charge of each period, in every case where the charge is constant or decreasing or increasing, and solve the problems of depreciation methods currently used, by obtaining the accumulated depreciation charge at any given time. We can choose diverse rational depreciation types for the characteristic of every asset with the new method, and compute the depreciation charge with consistency in all cases where assets are owned for partial period.

• Journal of ILASS-Korea
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• v.24 no.3
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• pp.114-121
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• 2019

The effect of injector driving current pattern on fuel injection rate of solenoid diesel common rail injector was studied by computer simulation. The time resolved fuel injection rate and injected quantity per stroke of a common rail injector driven with the five current patterns were computer simulated. The fuel injection rate and injected quantity per stroke according to the rail pressure and fuel injection period were also computer simulated. When the common rail injector was driven with the five driving current patterns of peak & hold, there was no difference in the fuel injection rate in the peak section regardless of all the current patterns of the five cases. On the other hand, the magnitude of the hold current value influenced the injection rate and injected quantity per stroke. That is, in the current pattern of three cases where the hold current value is equal to or more than a constant value of the peak current value, the fuel injection rates for the given common rail rail pressure and injection period are same one another. On the other hand, the current pattern of the two cases, in which the hold current value is smaller than a certain value, there is a large fluctuation in the fuel injection rate.

• Environmental Analysis Health and Toxicology
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• v.23 no.3
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• pp.213-220
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• 2008

The characteristics of PAHs accumulated on pine needles which were used as passive samplers of atmospheric POPs were studied. Atmospheric PAHs were accumulated on pine needles. The absorbed rate of PAHs was higher in gaseous state than in particulate and is not constant. The accumulation rate did not change too much among different classes of pine trees. Therefore young pine needles is better as a passive sampler of atmospheric PAHs for short monitoring period.

• Journal of Environmental Health Sciences
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• v.22 no.4
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• pp.25-32
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• 1996

The Bioconcentration factor(BCF) is used as an important criterion in the risk assessment of environmental contaminants. Also it can be used as indicator of biomagnification of environmentally hazardous chemicals through food-chain as well as a tool for ranking the bioconcentration potential of the chemicals in the environment. This paper reports the measured BCF value on carbofuran in Carassius auratus(goldfish), under steady state, and examined corelation between the BCF value and the depuration rate constant. Carassius auratus(goldfish) was chosen as test organism and test periods were 1-day, 3-day and 5-day. Experimental concentrations were 0.05, 0.10 and 0.50 ppm. Carbofuran in fish tissue and in test water was extracted with n-hexane and acetonitril. GC-ECD was used to detect and quantitate carbofuran. The depuration rate of carbofuran from the whole body of goldfish is determined over the 24-h period after treatment. The obtained results were as follows: 1. It was possible to determine short term BCFs of carbofuran through relatively simple procedure in environmental concentrations. 2. $BCF_1$ of carbofuran in concentration of 0.05, 0.10 and 0.50 ppm were 1.66, 1.64 0.61, $BCF_3$ were 2.08, 2.14, 0.66 and $BCF_5$ were 2.21, 2.57, 0.86, respectively. 3. Carbofuran concentration in fish extract was increased as increasing test concentration and prolonging test period, but $BCF_s$ in concentration of 0.50 ppm was greately decreased. 4. Determined deputation rate constants of carbofuran in concentration of 0.05, 0.10, 0.50 ppm were 0.076, 0.082 and 0.089, respectively. 5. It is considered that great decrease of $BCF_s$ in concentration of 0.50 ppm is due to high water solubility and stability of carbofuran in testwater. 6. It is suggested that low BCF of carbofuran is due to its relatively high water solubility and depuration rate, compared to BPMC, carbaryl and chlorothalonil.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.3
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• pp.93-104
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• 1994

One of the typical assumptions of the studies to determine economic production quantity is that yield rate of a given manufacturing process is 100% or constant after setup. However, in the real world, there are many manufacturing processes of which yield rates are quite low just after setup and then increasing with time until they reach the target rates which are set strategically. This period is usually called "stabilization period". During the stabilization period, defectives are produced, which incur cost (defective cost). In this study, an optimal production quantity for this situation is presented. Also, it is shown that defective cost acts like setup cost and therefore, increases the economic production quantity.