• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.185-190
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• 1982

In utilization of small size red muscled fishes like mackerel, sardine, and filefish, mechanical dressing is usually required. The removal of dark muscle is also necessary to improve qualify of the product, which could hardly be done by mechanical process. As a method of separating dark muscle, specific gravity method using sugar solution was investigated in this study. And the effects of the level of specific gravity, the size and density of meat particles, and stability of meat particle float on the separation of dark muscle were discussed. From the results, effective specific gravity, in case of sucrose solution, ranged 1.067 to 1.072 for mackerel, 1.062 to 1.070 for sardine, and 1.072 to 1.077 for filefish, respectively. The maximum separation of more than $90\%$ was obtained at specific gravity of 1.075, 1.070, and 1.075 in cases of mackerel, sardine and filefish, respectively. The size of meat particles which were ground with 0.2cm orifice plate was adequate to yield $90\%$ separation or above. The meat particle float in the glucose solution began to precipitate within 5 minutes after separation while 25 minutes in case of sucrose solution. Lipids were also fairly removed by the dark muscle separation process.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.71-84
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• 2007

Masan Bay is a representative semi-closed bay acted as a sedimentation reservoir with a slow current velocity and a poor water circulation in Korea. The pollutants from terrestrial sources into the Masan Bay have apparently environmental pollution problems, such as eutrophication, red tied, and hypoxia. In this study, An ecological modeling work was performed to estimate the material circulation including the growth of bivalve in ecosystem. Furthermore, the effect of water purification was calculated by filter feeding bivalve to particulate organic matter just like COD and phytoplankton. And Water quality management strategy by bio-purification of bivalve is derived through selection of location, quantification of bivalve aquaculture farm. The results showed that the optimum location for bivalve farming is where phytoplankton accumulation by physical processes is maximized and the optimum density and area of bivalve are 35 individuals $m^{-3}$ and ca. 500 hectare, respectively. When assuming conditions for the optimum growth of bivalve, COD could decrease by up to 18% even without other reduction of pollution loads.

• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.233-243
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• 2015

The bimodal flocculation of cohesive sediments in water environments describes the aggregation and breakage process developing a bimodal floc size distribution with dense flocculi and floppy flocs. A two class population balance equation (TCPBE) was tested for simulating the bimodal flocculation by a model-data fitting analysis with two sets of experimental data (low and high turbulent flows) from 1-D flocculation-settling column tests. In contrast to the Single-Class PBE (SCPBE), the TCPBE could simulate interactions between flocculi and flocs and the flocculation mechanism by differential settling in a low turbulent flow. Also, the TCPBE could perform the same quality of simulation as the elaborate Multi-Class PBE (MCPBE), with a small number of floc size classes and differential equations. Thus, the TCPBE was proven to be the simplest model that is capable of simulating the bimodal flocculation of cohesive sediments in water environments and water, wastewater treatment systems.

• Journal of Korea Water Resources Association
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• v.38 no.2
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• pp.133-142
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• 2005

The settling concentration of fine suspended solid particles(alumina(Al$_2$O$_3$) and quartz(SiO$_2$)) is investigated with the physico-chemical effects(initial concentration, pH and NaCl). Laboratory tests have confirmed the significant influence of increasing initial concentration and salinity which can lead to flocculation due to the intermolecular attraction. Furthermore, the influence of the pH value on the concentration-time corves of alumina has been on firmed. Besides a numerical model to predict the behaviour of cohesive deposit under still water is analyzed by solving the unsteady one-dimensional diffusion-advection equation with a explicit, implicit, Crank-Nicolson and finite difference scheme. The model predicts the existence of an equilibrium concentration. Application of the model with implicit centered difference to data from settling experiments shows a similar distribution.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.89-96
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• 2011

A three dimensional ecological model(EMT-3D) was applied to Ulsan Bay for the simulation of Dioxins. The simulated results of dissolved Dioxins were in agreement with the observed values, with a correlation coefficient(R) of 0.7951 and a coefficient of determination($R^2$) of 0.6265. The results of sensitivity analysis showed that partition rate, adsorption rate and bioconcentration factor were important factors. Therefore, the parameters must be carefully considered in the modeling. In the case of 50% and 80% total loads reduction, concentration of dissolved Dioxins was shown to be lower than 0.150 and 0.250 pg WHD-TEQ/L, respectively.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.44-50
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• 1986

Two fractions of ${\beta}-glucanase$(CMCase), two fractions of filter paper degradation enzyme (FPase) and one ${\beta}-glucanase$ fraction were partially purified from Fusarium moniliforme and applied to recovery process of red bean starch. Red bean were incubated with the fractions of CMCase and FPase at $50^{\circ}C$ for 2 hours and the starch granules are separated. Maximal sedimentation rate of red bean starch granules was obtained with treatment of the mixture solution of 0.004 units/ml of FPase and 0.3 units/ml of CMCase. In the enzyme treated process percent recovery of red bean starch granule increased about 7% and suspended solid in waste water was reduced about 40%, compared with those of control. The results indicated that red bean cell treated with cellulase fractions absorbed water more rapidly and specific gravity of starch granule increased.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.640-644
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• 2010

하천, 호소 등에서 공사 시 준설작업으로 인해 고탁수가 발생되며 이러한 탁수의 이송 확산은 수환경에 변화를 초래한다. 탁수는 준설작업 시 커터헤드(cutter head)가 해저면에 닿는 순간부터 작동을 멈출 때까지 계속하여 발생하며, 이러한 과정들이 반복되면서 많은 양의 부유토사가 발생하게 되고 고탁수현상이 일어난다. 이렇게 발생한 탁수는 수체흐름에 따라 이송 및 확산된다. 탁수발생은 수중의 빛 투과를 감소시켜 일차 생산자인 부유성 및 부착조류의 생육을 저해하고, 이들의 생산성 감소와 군집구성의 변화는 수서생태계의 먹이사슬을 통해 이들을 먹이로 하는 저서무척추동물과 어류의 현존량 감소와 종 구성에 영향을 미치고, 고농도의 현탁 입자는 어류 아가미에 염증을 유발하거나 점막의 파괴와 감염을 유발하여 치사시킬 수도 있다. 또한 과도한 부유 입자는 하류로 침강되어 하천 바닥에 서식하는 부착조류, 무척추 동물 및 곤충의 생육에 피해를 주고, 이것은 어류의 먹이에 영향을 미쳐 어류 개체수를 감소시키거나 산란된 물고기 알을 매몰시키거나 질식시키는 등 여러 가지 방법으로 수서생물상에 영향을 미치게 된다.(낙동강수계관리위원회, 2005) 따라서 준설작업에 있어 탁수의 이송 확산범위를 사전에 예측하고 국내 실정과 환경여건에 알맞게 적용되고, 실용화될 수 있는 수치모델링에 대한 기반핵심 기술개발이 필요하다. 현재 낙동강에서 진행되고 있는 준설현장에서 발생하는 부유탁수의 이송 확산과정을 이차원 흐름해석모형인 RAM2 모형과 오염물 이송 확산해석모형인 RAM4 모형을 이용하여 수치해석을 하고 분석함으로써 수치해석에 의한 부유탁수의 이송 확산모의 결과가 환경영향 범위를 예측하는 데에 적용될 수 있는지를 알아보고자 한다.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.423-430
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• 2004

This study intended to understand movements of turbid water in selective with drawal reservoirs before and after summer monsoon. Mean rainfall during November-May was low, compared to that during June-October. The reservoir water was discharged through watergates when previous rainfall and inflow exceeded 50 mm and $80\;m^3s^{-1}$, respectively. Intake towers were generally used except for the period of the high runoff. Average turbidity in gown-reservoir showed a difference of 29.9 NTU between premonsoon and postmonsoon. Diameter of particles of turbid water ranged between 0.435 and $482.9\;{\mu}m$. Fine particles such as clay were much denser than the larger particle. In the whole stations, clay component was relatively higher with a proportion of that in the particle distribution. Particle composition of turbid water showed that clay consisted of 94.4-98.9% and silt made of 1.1-5.6%. Analysis on turbid water movements derived from particle distribution showed a linear increase from the deep layer toward the surface layer in lower area of a reservoir. This was closely related with the hydraulic behavior of the reservoir, and heavily affected by the discharges through selective withdrawal towers and watergates. Turbid water originated from stream sediments in the middle area then resuspended in the down-reservoir causing a movement between the surface and middle layers of the reservoir. Therefore, such phenomenon needs to be understood for reservoir water quality management.

• Applied Microscopy
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• v.41 no.1
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• pp.55-60
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• 2011

Reduced plants of Spirodela polyrhiza consisting only of fronds, stalks and roots form turions during dormancy. In development, mature fronds produce offspring fronds by vegetative reproduction, and turions arise laterally from the mother frond before dormancy. The turion primordium is derived from the frond, while the frond primordium forms within the turion tissue. In the present study, cellular features, especially those of the plastids, of the above four tissue types have been examined and compared using electron microscopy. Proplastids, found to be numerous in the frond and turion primordia, differentiated into chloroplasts rapidly upon growth. The proplastids were small and the thylakoidal membrane system was rudimentary, howerver the chloroplasts exhibited variation by cell type. Chloroplasts were found within cells of the frond, stalk and root tissue. The thylakoidal membrane system, which formed grana stacks, was moderately developed within frond chloroplasts, while only a few were present in those of the stalk and root cortical cells. One to two starch grains were accumulated within frond chloroplasts, but little to none were found in stalk and root cortical chloroplasts. Contrary to other types of root chloroplasts, those found in the root cap cells developed chloroplasts similar to the frond type. Unlike proplastids of the turion primordia, numerous large amyloplasts occupied most of the turion cell volume. Moreover, the turion cell produced quite large starch grain (s) within the amyloplasts. Accumulation of the starch grains continued until they occupied the most of the stroma and in some cases, individual starch grains reached up to $9.0{\mu}m$ in length. None to little, if any, thylakoidal or internal membranous systems were seldom detected in these amyloplasts. Although the degree of cellular and tissue differentiation was rather minimal within their reduced body, the functional differentiation of Spirodela polyrhiza was very efficient, as is the case in other advanced species.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.299-309
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• 2019

This study was designed to assess the quality and quantity of food resources such as the chlorophyll a concentration (Chl-a), the particulate organic carbon (POC) and the particulate organic nitrogen (PON), on blood cocke (Tegillarca granosa Linnaeus) farms from May to November 2017 in the northwestern area of Yeoja Bay, Korea. The values of Chl-a, POC and PON were $1.69-7.68{\mu}g{\cdot}L^{-1}$ (average: $3.48{\mu}g{\cdot}L^{-1}$ in the surface), 0.88-2.58 mM (average: 1.97 mM) and 0.17-0.90 mM (average: 0.54 mM), respectively, and these values were higher in the spring and summer and lower in the autumn. Furthermore, Chl-a and POC had higher values on the bottom layer than those vales on the surface, while PON had higher values on the surface than those values on the bottom. The POC/PON ratio and POC/Chl-a ratio were 1.56-7.88 (average: 3.71 on the surface of the water) and 216-967 (average: 700 on the bottom of the water), respectively, with most of the carbon sources being sediment-accumulated particle organic matter, and the contribution by phytoplankton was assessed as being low. These results show that the food source of the blood cockle farms in the northwest area of Yeoja Bay seems to be abundant in quantity, but this is considered to be very poor in quality.