• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.187-193
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• 2003

The performance of a foam fractionator to remove TAN, $NO_2,\;NO_3$, TSS, protein, and $PO_4-P$ at different superficial air velocities and foam overflow heights was evaluated in a lab-scale seawater recirculating system for culture of Korean rockfish (Sebastes schlegeli). The foam overflow rates increased with the increase of superficial air velocities, but decreased with the increase of foam overflow heights. Concentrations of all the water quality variables in the foam condensates increased with the increase of foam overflow height, but decreased with the increase of superficial air velocities. TSS, protein, and phosphate enrichment factors were within the range of 6.4-39.4, 1.6-7.3 and 1.2-3.9, respectively. Low values of TAN, $NO_2,\;and\;NO_3$ enrichment factors were obtained and they indicate that foam fractionation is rot an effective way to remove dissolved inorganic nitrogen. The calculated maximum daily removal values for TSS and protein were 10.9 and 1.4g, respectively.

• Journal of Aquaculture
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• v.16 no.4
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• pp.216-222
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• 2003

In a simulated seawater aquaculture system, effects of different operating factors like the superficial air velocity (SAY), hydraulic residence time (HRT), protein concentration and foam overflow height on the removal of total suspended solids (TSS) by a foam fractionator, with 20 cm diameter and 120 cm height, were investigated. This experiment was performed on batch and consecutive modes for different combinations of the tested factors, using synthetic wastewater. In 5 consecutive trials, TSS concentration in culture tank water decreased faster, when the foam fractionator was operated at higher SAV and lower HRT. In batch trials, with increasing SAV, TSS removal rate increased, but decreased with increasing HRT. Higher protein concentration in the bulk solution resulted in higher TSS removal rate. TSS concentration in the collected foam condensates increased but the foam overflow rate decreased with increasing foam overflow height. Foam fractionation was effective for removing TSS in seawater aquaculture systems and its performance largely depended on the operating parameters, especially superficial air velocity.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.129-134
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• 2005

The behavior of whole system is affected by a minor change of system in the hydronic radiant floor heating system. Under partial load condition, the change of system resistance causes overflow of supply water. This unexpected effect is the cause of several problems in the heating system. In this study, we find some factors were validated with several computer simulations. After validation of this result, several conceptual solutions are evaluated to prevent overflow.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.774-788
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• 1999

To examine the enhancement mechanism of condensing heat transfer through microfin tube, the condensation experiments with refrigerant HCFC 22 are performed using 4 and 6 kinds of microfin tubes with outer diameter of 9.52mm and 7.0mm, respectively. Used microfin tubes have different shape and number of fins with each other The main heat transfer enhancement mechanism is known to be the enlargement of heat transfer area and turbulence promotion. Together with these main factors, we can find other enhancement factors by the experimental data, which are the overflow of the refrigerant over the microfin and microfin arrangement. The overflow of the refrigerant over the microfin can be analyzed by the geometric shape of the microfin. Microfin tubes having a shape which can give much overflow over the microfin show large condensing heat transfer coefficients. The effect of microfin arrangement is related to the heat transfer resistance of liquid film of refrigerant. The condensing heat transfer coefficients are high for the microfin tube with even distribution of liquid film.

• Ocean and Polar Research
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• v.25 no.3
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• pp.269-275
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• 2003

Effects of different operating factors including superficial air velocity (SAV), hydraulic residence time (HRT), protein concentration, and foam overflow height on protein removal by a foam fractionator in simulated seawater aquaculture system were investigated. This experiment was conducted on batch and consecutive modes at different combinations of the affecting factors. The foam fractionator had a diameter of 20cm and a height of 120cm and the experiment was conducted with synthetic wastewater. In 5 consecutive trials, protein concentrations in culture tank water decreased faster when the foam fractionator was operated at higher SAVs and lower HRTs. In batch trials, protein removal rates increased with an increase in SAV but decreased with an increase in URT. Higher protein concentrations in the bulk solution resulted in higher protein removal rates. Protein concentrations in the collected foam condensates increased but the foam overflow rates decreased with the increase of foam overflow heights. The results of this experiment indicate that foam fractionation would be an effective way for protein removal in seawater aquaculture systems and the performance of the foam fractionator depends largely on the operating parameters, especially SAV.

• Journal of Korea Game Society
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• v.20 no.1
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• pp.33-46
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• 2020

The purpose of this study was to examine the differences in the factors that determine the game immersion of adolescents by the level of school. The results of this research showed that among the internal variables, loneliness, self-control, and among the psychological variables, game leadership, game subjective norm, and game efficacy played a common role in game addiction in all groups. To be specific the factors determining game overflow by the level of the school were identified as discriminatory. These findings can help making policies or developing a program on adolescent's overflow.

• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.251-259
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• 2002

Flow characteristics occurring a side-weir overflow in rectangular channel is investigated in this study. A numerical model based on the two -dimensional shallow-water equations is employed to review the factors influencing on the side- weir overflow discharge and the change of flow depths and velocities. It is found that the discharge coefficient which has the most significant influence on the overflow is affected by geometric characteristics of a side-weir, Froude number of the main channel flow and the flow depth of the main channel at the starting point of a side-weir. And the discharge coefficient applicable to a practical design of a side-weir is proposed by deriving a relationship between Froude number of the main channel flow at the starting point of a side-weir and Froude number of the main channel flow.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.388-398
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• 2012

In this study, Entropy method and PROMETHEE(Preference Ranking organization METHod for Enrichment Evaluations) which is one of the multi criteria decision making methods are applied to estimate the relative inundation risk ranking of the urban sewer systems. Then, the evaluation factors were selected considering two main items to estimate the inundation risk using Entropy and PROMETHEE. In the first item considering topographical and environmental factor, average elevation, average slope, width of area, population, density of conduit were selected as the detailed factors of first item which have influence of the overflow occurrence and damage scale in urban sewer system. And, the relative reliability of sewer network was considered as the second item which can quantify the inundation appearance. Then, the reliability is estimated considering the number of overflow nodes and overflow volume simultaneously. Therefore, the suggested inundation risk evaluation method can be used as the evaluation index for sewer networks and contribute to decision making for the sewer rehabilitation policy.

• Journal of the Korean GEO-environmental Society
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• v.16 no.3
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• pp.5-13
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• 2015

Wave overflow can cause a failure of sea dike structure. Based on the results of the field surveys on mound-type sea dike, the failure of vicinity of crown and the scouring of toe at the landward was revealed as the most representative failure example. One of the main factors related to this failure pattern is overflow-induced pressure and velocity. Thus, in this study the analytical equations which can determine the pressure and the velocity induced by overflow in sea dike were proposed and verified. To accomplish this, assumed that the flow is quasi-steady and irrotational, and concentric circular streamlines around the vicinity of crown and toe of the sea dike. Flow was assumed as critical state and Bernoulli equation was used to develop the equations that can determine the pressure and velocity at the vicinity of crown and toe of the sea dike. Using these equations, the pressure and the velocity were calculated in condition of various overflow depths and radiuses of circular streamline. Based on the calculation results, while a negative pressure was occurred at the vicinity of crown, a significant amount of positive pressure occurred at the toe. The existence of flow-induced shear stresses was also confirmed. In addition, the limitation of the proposed equations was discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.23-27
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• 2006

Brazing Failure has been occurred in the process of thrust chamber assembly. The possible factors have been analyzed by sample tests. The actual causes of 'Overflow' phenomenon have been investigated horn Brazing Material and fabrication of Piece Parts. The rejection rate of process has been improved by appling this results to a real brazing process.