• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.109-116
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• 1999

To establish optimum cycle of the inverter-driven heat pump with a variation of frequency, the bypass orifice, which is a short tube having a bypass hole in the middle, was designed and tested. Flow characteristics of the bypass orifice were measured as a function of orifice geometry and operating conditions. Flow trends with respect to frequency were compared with those of short tube orifices and capillary tubes. Generally, the bypass orifice showed the best flow trends among them, that will enhance the seasonal energy efficiency ratio of an inverter heat pump system. Based on experimental data, the semi-empirical flow model was developed to predict mass flow rate through bypass orifices. The maximum difference between measured data and model's prediction was within ${\pm}5%$.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.127-131
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• 2022

The effect of bypass diodes on the output energy of solar cells was investigated under the condition of partial shading. The maximum power point was estimated using the perturbation & observation algorithm, taking into account the correlation effect between the arrangement and number of bypass diodes. The performance of the bypass diode was tested under the consideration of the partial shading effect and simulated using a Matlab/Simulink.

• Journal of Chest Surgery
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• v.33 no.8
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• pp.648-654
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• 2000

Background: Cardiopulmonary bypass during open heart surgery causes systemic inflammatory respose. IL-10 is an anti-inflammatory cytokine that inhibits inflammatory process and protects organ function by down regulation of pro-inflammatory cytokine release and maintenance of blood level balance with pro-inflammatory cytokines. Mateial and Method: Plasma IL-10 levels were measured and analyzed in 22 patients who underwent open heart surgery (11 cases of coronary artery bypass graft, 11 cases of valve replacement) under cardiopulmonary bypass since 1988 January to July at Department of Thoracic and Czardiovascular surgery, Yeungnam University Hospital. 1g of methylprednisolone was administrated to thirteen patients randomly. Blood samp.es were taken and collected at the time of induction of anesthesia, 10 min before cardiopulmonary bypass, 10 min after starting of CPB, 10 min aftr aortic cross clamping, 10 min after ACC release, and 10 min, 2 hours, and `5 hours after CPB respectively. The plasma levels of IL-10 were determined by enzyme-linked immunosorbent assays(ELISA). Wilcoxon-Raule Sum test was used for statistical analysis. Result: In all 22 patients, cardiopulmonary bypass time was used for statistical analysis. Result: In all 22 patients, cardiopulmonary bypass time was 171$\pm$41.4 min and aortic cross clamp time was 118$\pm$36.5 min. Peak IL-10 level was achieved at 10 min after ACC(361.0$\pm$52.81pg/ml) and was decreased sharply at 2 hours after CPB. Peak IL-10 level was correlated positively with aortic cross clamp time(p=0.011); however, it did not correlated with bypass time(p=0.181). In valve replacement group, mean IL-10 level at peak point was 567.89$\pm$107.69 pg/ml and was significantly higher than that of coronary artery bypass group(205.67$\pm$192.70 pg/ml)(p<0.001). ACC time in valve replacement group was significantly longer than that of coronary artery bypass group(p<0.01), however, bypass time was not(p=0.212). Thirteen patients with steroid pretreatment before starting of CPB showed relatively higher plasma IL-10 level than in control group, however, no statistical significance was noted(p=0.19). Conclusion: plasma level of IL-10 was increased in association with cardiopulmonary bypass and revealed peak at 10 min after ACC release. IL-10 level was correlated positively with ACC time. Therefore, systemic inflammatory respeonse in association with cardiopulmonary bypass could be decreased by reducing ACC time during cardiac surgery.

• Journal of Microbiology and Biotechnology
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• v.7 no.5
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• pp.287-292
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• 1997

The role of glyoxylate bypass in lysine production by Corynebacterium glutamicum ssp. lactofermentum ATCC21799 was analyzed by using cloned aceA and aceB genes which encode enzymes catalyzing the bypass. Introduction of a plasmid carrying aceA and aceB to the strain increased enzyme activities of the bypass to approximately 5 fold on acetate minimal medium. The strain with amplified glyoxylate bypass excreted 25% more lysine to the growth medium than the parental strain, apparently due to the increased availability of intracellular oxaloacetate. The final cell yield was lower in the strain with amplified glyoxylate bypass. These changes were specific to the lysine-producing C. glutamicum ssp. lactofermentum ATCC21799, since the lysine-nonproducing wild type Corynebacterium glutamicum strain grew faster and achieved higher cell yield when the glyoxylate bypass was amplified. These findings suggest that the lysine producing C. glutamicum ssp. lactofermentum ATCC21799 has the ability to efficiently channel oxaloacetate, the TCA cycle intermediate, to the lysine biosynthesis pathway whereas lysine-nonproducing strains do not. Our results show that amplification of the glyoxylate bypass efficiently increases the intracellular oxaloacetate in lysine producing Corynebacterium species and thus results in increased lysine production.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.153-159
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• 2012

Bypass anastomosis is frequently adopted for surgical treatments of stenosed coronary arteries. Optimal coronary bypass grafting should be investigated to improve the patency in arterial bypass techniques. The objective of this study is to analyze the effects of Y-grafting bypasses and T-grafting bypasses for various bifurcation and anastomotic angles. In order to find the optimal geometric configuration, the hemodynamic characteristics are obtained and compared with each other for different geometries. We found that both the left anterior descending artery (LAD) and left circumflex artery (LCX) blood flows were distributed evenly when the bypass grafting angle and bifurcated angle were $30^{\circ}$ and $15^{\circ}$, respectively,.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.107-112
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• 1992

Feeding of bypass protein to lactating animals have been suggested by many research scientists as a way to increase the nutrient supply at the intestinal level thereby enhance animal production in ruminant animals. A feeding trial with a formulated bypass protein feed on straw based ration was carried out by using lactating cross bred cows at the stage of 4th month of their lactation. Bypass protein feed was fed at 5 different levels. Urea Molasses Block was used as a nitrogen source to the rumen microflora. In order to reduce the heat increment straw intake was restricted to all the animals. Urea Molasses Block intake was noticed varying in proportion with the bypass protein feed intake. Milk production was observed increasing in accordance with the level of bypass protein feed intake. However, the maximum response was noticed in cows that were fed 3 kg bypass protein feed. The nutrient availability at this stage was below the NRC (1988) requirements. Other remarkable finding was that the cows maintained the persistency of milk production even after 3rd month of lactation when the ambient temperature was $40^{\circ}C$.

• Journal of Chest Surgery
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• v.21 no.2
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• pp.240-245
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• 1988

This study was prospectively planned to realize the reduction of calcium ion in serum along with the cardiopulmonary bypass[CPB], to find out the cause of the reduction, and to verify the justification of the classical methods of calcium replacement. Nine patients with various open heart surgeries by CPB in 1987 wee selected at random. Calcium chloride was added as follows:: For each unit of ACD blood transfusion, 600mg of calcium chloride was added. In case of massive transfusion, 600 mg of calcium chloride was injected every 2 or 3 units of transfusion. On occasions such as weaning from CPB, or following defibrillation, or hypotension, weak myocardial contractility of the heart, calcium chloride was needed in an amount of 10 mg / kg. In ICU, calcium chloride was limited to use in low serum level or in emergency use. Total calcium decreased early bypass and progressively increased above the preoperative value during late bypass and three hours thereafter, Ionized calcium increased during late bypass and three hours following. Total and ionized calcium depicted similar patterns of change during open heart surgery. Decrease of the calcium at the early bypass was thought from reduction of total protein and alkalosis during bypass. Meanwhile, increase of both calciums during the end of surgery was presumably attributable to addition of calcium chloride in priming solution, injections of calcium chloride in the process of termination of bypass. We conclude that enough calcium was replaced by the classical methods of calcium supplement.

• Journal of computational fluids engineering
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• v.14 no.2
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• pp.59-67
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• 2009

An accurate prediction of the bypass flow is of great importance in the VHTR core design concerning the fuel thermal margin. Nevertheless, there has not been much effort in evaluating the amount and the distribution of the core bypass flow. In order to evaluate the behavior and the distribution of the coolant flow, a unit-cell experiment was carried out. Unit-cell is the regular triangular section which is formed by connecting the centers of three hexagonal blocks. Various conditions such as the inlet mass flow rate, block combinations and the size of bypass gap were examined in the experiment. CFD analysis was carried out to analyze detailed characteristics of the flow distribution. Commercial CFD code FLUENT 6.3 was validated by comparing with the experimental results. In addition, SST model and standard k-$\varepsilon$ model were validated. The results of CFD simulation show good agreements with the experimental results. SST model shows better agreement than standard k-$\varepsilon$ model. Results showed that block combinations and the size of the bypass gap have an influence on the bypass flow ratio but the inlet mass flow rate does not.

• Journal of Energy Engineering
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• v.11 no.2
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• pp.130-135
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• 2002

Bypass air conditioning systems are divided into three types; outdoor air bypass, mixed air bypass and return air bypass system. Among bypass air conditioning systems, a return air bypass system is more effective than other two systems because it doesn't induce unconditioned outdoor air into conditioned room. The numerical study on the bypass air conditioning system shows this system can maintain indoor RH(Relative Humidity) less than a conventional CAV (Constant Air Volume) air conditioning system by adjusting face and bypass dampers at part load. A simulator was built to compare results of a numerical experiment and those of a simulator experiment. The results of the simulator experiment was nearly same as those of the numerical experiment; when a design sensible load (the ratio of sensible load to total sensible load) was 70 percent (at this time, RSHF=0.7), indoor relative humidity (in case of both numerical experiments and simulator experiments) was maintained below 60% specified by ASHRAE STANDARD 62-1999. The bypass air conditioning system is expected to be applied to many buildings where the Percentage of latent loads or air change tate is high.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.571-574
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• 1997

Attempts were made in the laboratory to produce bypass fat using acid oil by precipitation and fusion methods. The degree of saponification by both of these methods was above 80 percent. Where heating facilities are not available, precipitation method could be used, otherwise, fusion method of bypass fat production is found to be more convenient, especially for commercial scale operations as handling of large volume of solutions is eliminated. Bypass fat thus produced was tested in vitro for rumen fermentation. Incorporation of acid oil in the incubation medium reduced TVFA conc. from 127.06 to 124.09 mM/l SRL and increased ammonia-N levels from 210.50 to 223 mg/l SRL indicating that the microbial activity was affected on incorporation of acid oil in the incubation medium. However, incorporation of bypass fat in the incubation medium did not significantly affect TVFA conc. as well as ammonia-N levels. In another experiment, nine rumen fistulated sheep in three groups of three each were fed bypass fat at two different levels. Dry matter disappearance in 24 h from the nylon bags suspended in the rumen of animals under different groups was found to be $47.74{\pm}1.10$, $47.55{\pm}0.21$ and $50.74{\pm}1.11$ in group I (control), group II (fed bypass fat 50 g/day) and group III (fed bypass fat 100 g/day), respectively. These studies indicated that it is possible to produce bypass fat from acid oils, a by-product of oil refining process, and its feeding did not affect rumen fermentation.