• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.2
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• pp.52-60
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• 2001

The need to control the oil content in oily bilge water discharges to meet the increasing stringent seawater pollution standards has led to the development of gravity type separators. Among the several gravitational methods, a plate type oily water separator can be used as an assistant equipment for the oil filtering system to meet the present IMO standard of 15 ppm, because it is believed to be an efficient method dealing with a large amount of rich oil with high specific gravity. The purpose of this paper is to examine the efficiency of oil/water separation with the characteristics of separating plate arrangement. An experimental study was carried out to analyse an efficient treatment oil-water mixture with variation of operating parameters, including flow rates, inlet oil concentrations and the height between the plates. The experimental results show that the height between the plates has a significant effect on the separation efficiency. The best efficiency was acquired when the ration of the height between the plates the plates to distance(H/Ci) was 2 with lower inlet oil concentration and lower flow rate.

• Journal of Marine Bioscience and Biotechnology
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• v.9 no.1
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• pp.8-13
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• 2017

Cost-effective microalgae harvesting methods are necessary for economical production of algal biodiesel. In this study, membranes with various pore sizes and materials were examined for their potentials in application to gravity-filtration of Tetraselmis sp. KCTC12432BP. For this test, 10 L of Tetraselmis sp. culture (2 g/L) was loaded on each membrane and filtration rates were measured. Among the tested materials, a woven cotton fabric showed the fastest water drain rate (0.73 L/hr) without serious cell leakage. Cell density of the concentrates after filtration was 6.8 g/L, indicating 3.4-fold concentration compared with the initial algal culture. The result suggests that the woven cotton fabric could serve as filtration membrane for harvesting Tetraselmis sp. among the tested ones.

• Journal of Environmental Health Sciences
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• v.1 no.1
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• pp.9-13
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• 1974

For the purpose of determining the degree of freshness and bacterial contamiation of poultry farm eggs, the author collected 550 specimens from poultry farm, during the period from July 22 through October 3, 1973. Eggs of poultry farm were stored at $4{\pm} 1{\circ}$(Relative humidity 67~86%), $18\pm 1\circ$(70~80%) and $25\pm 1\circ$(73~82%) during 20 days. The results are summarized as follows: 1) Egg weight was decreased $0.97\pm 0.27$ gm at $4\pm 1\circ$, $1.68\pm 0.25$ gm at $18\pm 1\circ$ and $2.76\pm 0.30$ gm at $25\pm 1\circ$ after 20 days. 2) Specific gravity of fresh eggs was found to average 1.0785. 3) Yolk index of fresh eggs was found to average 0.419. 4) The regression equation between Yolk index and days was obtained y=0.417-0.001x (r=-0.481, p<0.05) at $4\pm 1\circ$, y=0.394-0.004 x (r=-0.738, p<0.01) at $18\pm 1\circ$ and y=0.391-0.011 x (r=-0.958, p<0.001) at $25\pm 1\circ$. 5) The regression equation between Yolk index and NaCl concentration (specific gravity) was obtained y=-0.001+0.04 x (r=0.796, p<0.001). 6) pH of albumin was changed from 8.0 to 8.8, 9.2 and 9.3 at $4\pm 1\circ$, $18\pm 1\circ$ and $25\pm 1\circ$ after 20 days. 7) Total Viable Bacteria in air cell was increased slowly according to the stored period at each temperature.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.189-194
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• 2022

The formation of a new world order is primarily caused by new conditions and military operations on the European continent. The intensification of military-political tension led to the formation of new centers of power and gravity, which in turn led to the concentration of weapons and general militarization. Changes in the world order as a result of military conflicts and an increase in hot spots in the world, an increase in threats and the formation of centers of military gravity, the inability of existing institutions to resolve the situation lead to the need to develop new security mechanisms. Studies show that in the current situation, the countries of the Baltic countries are especially actively increasing their level of technologization of the army and militarization in general. The creation of any alliance is always conditioned by the presence of external threats. Naturally, the increase in the number of threats creates preconditions for the development of new forms of cooperation within existing military alliances. It seems obvious that due to the current situation in the context of the military conflict and military aggression of Russia in Ukraine, as well as its constant threats, including to the Baltic countries, there is a need to form a certain alliance that can protect the eastern border of Europe and form a certain border between European countries and aggressor countries. The Baltic countries are actively involved in these processes, in addition, it is the Baltic countries that can enter the new military alliance proposed by Britain, which will unite Poland, Ukraine, the Baltic countries and, possibly, Great Britain.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.5
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• pp.208-215
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• 2005

The 10mm diameter aggregates made of clay, carbon and $Fe_2O_3$ were prepared to investigate the mechanism of black core formation. The specific gravity, absorption rate, percent of black core area, fracture strength, total Fe analysis, and XRF were measured at various compositions, sintering temperatures, sintering times, sintering atmospheres, and sintering methods. Small addition of $Fe_2O_3$ did not affect physical properties of the aggregates; however, the percent of black core area increased with increasing carbon contents and increasing sintering temperature. Specific gravity of the aggregates decreased and the water absorption ratio increased with increasing percent of black core area. The aggregates sintered at oxidation atmosphere showed clear border between shell and black core area. Hence, the aggregates sintered at reduction atmosphere showed only black core area in the cross-section of the aggregates. The specific gravity of the aggregates sintered at reduction atmosphere increased with increasing carbon contents and that was the lowest of all comparing other aggregates sintered at different atmospheres. Adsorption rate increased with increasing carbon contents at all atmospheres. The fast sintered aggregates showed lower specific gravity, higher absorption rate, and more black core area than the normally sintered aggregates. It was turned out that the aggregates having more black core area showed higher fracture strength than that of aggregates with no black core area. From the total Fe analysis, the concentration of Fe and FeO was higher at black core area than at shell. Because the concentration of $Fe_2O_3$ in the shell was higher than other area, the color of the shell appeared red. It was also turned out from the XRF analysis that carbon was exist only at black core area.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.401-410
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• 2016

Since the late 19th century, scientific logic and techniques have been used extensively in the field of clinical pathology, including many laboratory tests utilizing various apparatuses and instruments. Among the techniques to measure hemoglobin, the visual color comparison method was most popular around this time; the specific gravity method and gasometric method were not widely adopted. Instruments that use the visual color comparison method include Gowers' hemoglobinometer, von Fleischl's hemoglobinometer, Dare's hemoglobinometer, Oliver's hemoglobinometer, Haden-Hausser hemoglobinometer, and Spencer Hb meter. Initially, the visual color comparison methods were used to diluate and hemolyze blood with distilled water and then to measure its color. Later, these methods were further developed to measure hemoglobin without dilution, and improved with the formation of acid or alkaline hematin ensuring the stability of color development. Hammerschlag's method as well as the Schmaltz and Peiper's methods were based on specific gravity measurement, but they were not widely used. The gasometric method used the Van Slyke gasometer, indirectly measuring the hemoglobin concentration. This method provides the most accurate results. This survey examined the characteristics and limitations of hemoglobinometers and methods used to measure hemoglobin from the late 19th century to the early-and mid-20th century. Moreover, this study aims to improve the understanding and applicability of the current methods and emerging technologies used in measuring hemoglobin. It is also expected that this investigation is the starting point to promote awareness of the need to organize historical data for a variety of historical relics of the diagnostic laboratory tests.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.2
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• pp.108-119
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• 2004

The breakwater extension at Anmok Harbor has resulted in erosional stresses along the wide range of shorelines immediately south of the harbor. In this study, therefore, the downdrift affects caused by the breakwater extension are investigated through both analytical and numerical approaches. In addition, this study stresses the need of monitoring and analysis system for the effective integrated coastal zone management and shows through the case study of Anmok Harbor how the numerical experiments are accomplished for the coastal zone management. The numerical model system, which predicts the seabed changes obtained from the difference between the rates of sediment pickup and settling due to gravity, is combined with the wave, wave-induced currents, and suspended sediment transport models. A new relationship between the near-bed concentration and the depth-mean concentration, which is required in estimating the settling rates. is presented by analyzing the vertical structure of concentration.

• Journal of environmental and Sanitary engineering
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• v.24 no.1
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• pp.33-39
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• 2009

In order to investigate effect of metal ion and antioxidant on rancidity of crude rapeseed oil (CRO), $Fe^{2+}$, $Cu^{2+}$, $Co^{2+}$, $Ni^{2+}$, $Cr^{2+}$, $Sn^{2+}$, $Mn^{2+}$, $Zn^{2+}$, and antioxidants including BHA, Vitamin C, and Tocopherol were used. The specific gravity and refractive index of CRO were $0.92g/cm^3$ and 1.45, respectively. The chromaticities of light, red, and yellow in CRO were 88.6 and 98.7, respectively. Among various fatty acids, Oleic acid (C18:1) concentration was highest, 62.3% and Linoleic acid (C18:2) concentration was 19.16%. In the case of Linolenic acid (C18:3) and Palmitic acid (C16:0), they were 9.88 and 5.2%, respectively. The concentrations of unsaturated fatty acids and saturated fatty acid were 92.2 and 7.8%, respectively. The degree of expediting rancidity of CRO was an order of $Fe^{2+}$> $Cu^{2+}$> $Cr^{2+}$> $Zn^{2+}$> $Ni^{2+}$> $Al^{2+}$> $Mn^{2+}$> $Mn^{2+}$> $Sn^{2+}$> $Co^{2+}$> $Li^{2+}$. Especially, when $Cu^{2+}$ and $Fe^{2+}$ was used, the peroxide value concentration was about 4.0 fold higher than non addition of them. The inhibition effect of rancidity of CRO using antioxidant with $Cu^{2+}$ and $Fe^{2+}$ was an order of BHA> Vitamin C> Tocopherol.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.215-221
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• 2006

This research presents results from laboratory and pilot-scale experiments to remove high-nitrate in pickling wastewater using the sequencing batch reactor (SBR) as a biological method. During the experimental periods, the influent concentrations of NOx-N and $Ca^{+2}$ were analyzed to be 350-1,600 and 700-800 mg/L, respectively. In order to provide carbon source for denitrification, methanol has been added in proportion to the influent nitrate loading. The mean concentrations of MLSS and MLVSS, the fraction of volatile solids in sludge and the sludge volume index were measured to be 27 g/L, 5 g/L, 18.5% and 7.5, respectively. The solid retention time was kept in the range of 18 to 22 days, specific denitrification rate ($U_{dn}$) was $0.301g{NO_3}^--N/gVSS/day$. The oxidized nitrogen concentration of effluent ranged 2-34 mg/L with an average of 5.2 mg/L, the overall reduction in total nitrogen was more than 99.2%. In order to treat the pickling wastewater including the high concentration of nitrate and $Ca^{+2}$, the continuous flow process is not suitable because the specific gravity of the sludge is considerably increased by $Ca^{+2}$, thus the SBR process is shown to be very effective to treat the pickling wastewater.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.180-185
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• 2001

In order to regulate the physical characteristics of an ocean dumping material in the south-eastern East Sea, the diffusion characteristics with the observation, hydraulic experiment and numerical experiment data are investigated. The main results are as follows; (1) Spying CTD observation result of the area of Jung in the East Sea, the ocean dumping area had influenced the Tsushima warm current of high temperature and salinity. Horizontal turbulent diffusivity is 1.913${\times}$10$^{7}$ $\textrm{cm}^2$/sec by drogue tracking. (2) From the experiment of settling, the initial settling velocity of each material is 1.0∼2.7 cm/sec according to the specific gravity and initial concentration. In the pycnocline, particles didn't settle under the pycnocline any more and accumulated. It is signified that calculation of the sedimentation rate of the ocean dumping material including of vertical diffustion must be regard the pycnocline in the ocean area have well-developed pycnocline. (3) Vertical turbulent diffusivity were 2.219${\times}$10$^{-8}$∼8,874${\times}$10$^{-4}$ $\textrm{cm}^2$/sec from the experiment of settling. And, the pycnocline influenced the vertical turbulent diffusivity. (4) From the result of diffusion simulation in the East Sea, the co-concentration line of 0.05 ppm and 0.1 ppm are limited at dumping area after 200 days. The constant concentration line of 0.01 ppm is distributed to the vicinity of Ulleungdo and Tokdo, but isn't distributed to the coastal area of East Sea and southern area of Jung in the East Sea.