• Polymer(Korea)
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• v.34 no.4
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• pp.333-340
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• 2010

Zaltoprofen, a propionic acid derivative non-steroidal anti-inflammatory drug (NSAID), is known to have powerful inhibitory effects on acute, subacute and chronic inflammation. We developed poly(lactide-co-glycolide)(PLGA) microspheres loaded with zaltoprofen for sustained controlled delivery using an oil-water solvent evaporation methods by varying PLGA molecular weight and cosurfactant contents. Physicochemical properties and morphology of zaltoprofen-loaded PLGA microspheres were investigated by scanning electron microscope, X-ray diffraction and differential scanning calorimeter. The size of microspheres increased with the molecular weight of PLGA and the content of cosurfactants. The increase of PLGA molecular weight and cosurfactant content decreased the porosity of microspheres, subsequently resulting in the slow drug release. The results demonstrated that the adjustment of PLGA molecular weight and the cosurfactant content allowed us to control the drug release profiles of drug-loaded microspheres.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.503-516
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• 2021

Autonomous fire detection and suppression system requires advanced technology for complex detection technology and injection/control technology for accurate hitting by fire location. Also, foam spraying should be included to respond to oil fires. However, when a single spray monitor is used in common, water and foam spray properties appear different, so for accurate fire suppression, research on the spray trajectory and distance will be required. In this study, experimental studies and numerical analysis studies were combined to analyze the foam spray characteristics through the spray monitor developed for the establishment of an autonomous fire extinguishing system. For flow analysis of foam injection, modeling was performed using OpenFOAM analysis software, and the commonly used foaming agent (Aqueous Film-Forming Foam) was applied for foam properties. The injection distance analysis was performed according to the injection pressure and the injection angle according to the form of the foam, and at the same time, the results were verified and presented through the injection experiment.

• Journal of the Korean Society of Food Culture
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• v.23 no.4
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• pp.507-513
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• 2008

The development of soy cutlets containing textured soy protein (TSP) as a meat analog was studied. In order to decrease the beany flavor and to increase the texture, TSP was treated with 0.3% Flavourzyme or 0.1% Protamex for 10 or 20 min, respectively. The degree of hydrolysis for TSP treated with Protamex was higher than that treated with Flavourzyme. Hydrolysis was observed to increase as the reaction time was increased for both Flavourzyme and Protamex. The water holding capacity of TSP treated with Protamex for 10 min was the highest, and that treated with Flavourzyme for 20 min was similar to that of Protamex treatment for 20 min. The oil binding capacity of TSP treated with Protamex for 20 min was the highest. The hardness of the soy cutlets using TSP treated with Flavourzyme for 10 min was higher than that treated for 20 min, while that of Protamex treated for 20 min was higher than that treated for 10 min. The cohesiveness of the soy cutlets using TSP treated with Flavourzyme or Protamex for 10 min was higher than those treated for 20 min. The chewiness of the soy cutlets treated with Flavourzyme for 10 min was higher than for those treated for 20 min, while those treated with Protamex for 20 min was higher than those treated for 10 min. The springiness of TSP treated with Flavourzyme for 20 min was higher than those treated for 10 min, and higher than those treated with Protamex for 10 or 20 min. For sensory evaluation, the beany flavor of the soy cutlets treated with Protamex for 20 min was the weakest. The flavor and chewiness of both a pork cutlet and a soy cutlet treated with Protamex for 20 min were the best. In the overall quality, soy cutlets treated with Protamex for 20 min was the most desirable. In conclusion, soy cutlets treated with 0.1% Protamex for 20 min could be a reasonable substitute of pork cutlets.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.53-64
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• 2020

A 2㎥/d combined wastewater treatment pilot plant containing the multi-stage vertical stacking type nitrification reactor was installed and operated for more than 1 year under the operating conditions of the short-circuit nitrogen process (pH 8, DO 1mg/L and Internal return rate 4Q from nitrification to denitrification reactor). For economically the combination treatment of food wastewater and the leachate from a landfill, the optimal combination ratio was operated by adjusting the food wastewater with the minimum oil content to 5-25% of the total throughput. The main treatment efficiency of the three-phase centrifugal separator which was introduced to effectively separate solids and oil from the food wastewater was about 52% of SS from 116,000mg/L to 55,700mg/L, and about 48% of normal hexane (NH) from 53,200mg to 27,800 mg/L. During the operational period, the average removal efficiency in the combined wastewater treatment process of BOD was 99.3%, CODcr 94.2%, CODmn 90%, SS 70.1%, T-N 85.8%, and T-P 99.2%. The average concentrations of BOD, CODcr, T-N, and T-P of the treated water were all satisfied with the discharge quality standard for landfill leachate ("Na" region), and SS was satisfied after applying the membrane process. On-site leachate had a relatively high nitrite nitrogen content in the combined wastewater due to intermittent aeration of the equalization tanks and different monthly discharges. Nevertheless nitrite nitrogen was accumulated, denitrification from nitrite nitrogen was observed rather than denitrification after complete nitrification. The average input of anti-forming chemical during the operation period is about 2L/d, which seems to be economical compared to the input of methanol required to treat the same wastewater.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

• Resources Recycling
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• v.10 no.3
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• pp.51-59
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• 2001

Impurities removal from waste carbon black was carried out to produce high-grade carbon black. A large amount of hydrophilic carbon black is produced as a byproduct of the hydrogen production process by flame decomposition of water. Due to its impurities content such as sulphur, iron, ash, etc., it can only be used as low-grade carbon or burnt out. High-grade hydrophilic carbon black is 3~5 times more expensive than oil-based carbon black because of high production cost associated with process complexly and pollutant treatment. Hydrophilic carbon is normally used for conductive materials for batteries, pigment for plastics, electric wire covering, additives for rubber, etc. In these applications, impurity content must be blow 1 fe. In this study, magnetic separation, froth flotation and ultrasonic treatment were employed to remove impurities from the low-grade hydrophilic carbon black. Results showed that the ash, iron and sulphur content of product decreased to less than 0.01 wt.%, 0.01 wt.% and 0.3 wt % respectively and the surface area of product was about 930 $m^2$/g for conductive materials.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.488-494
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• 2006

This study was carried out in order to investigate the feasibility of utilizing concentrated sunmul (soybean curd whey), which is a waste by-product of soybean curd processing, as a functional food ingredient. Sunmul Powder was concentrated by ultrafiltration and spray dried with or without dextrin. Oil adsorption capacity of UF retentate powder was similar to that of ISP (Isolated Soy Protein) and higher than that of sunmul powder, whereas water holding capacity of UF retentate powder was lower than that of ISP. Protein solubility of all types of UF retentate powder was significantly higher than that of ISP at pH 2.0-10.0 with the lowest protein solubility seen at pH 4.0 and solubility increasing as the conditions became more acidic or alkaline. Emulsifying activity indexes of UF retentate powder at pH 2.0-10.0 were not influenced by pH. Emulsion stability of 4% sunmul solution was lowest at pH 4.0, but that of UF retentate powder was higher at acidic pH values and decreased with increasing pH. Foaming capacities of sunmul and UF retentate powder were high at pH 4.0-6.0, but the foam of UF retentate powder disappeared within 20 minutes in all conditions of pH.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.317-331
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• 1989

Chaenogobius laevis inhabit brackish waters. Adult male protects egg mass laid under the stones. The egg with small oil globule varied from 3.40 to 4.04 mm in diameter. When water temperature is $22.0\~23.0^{\circ}C$, larvae hatched about 113 hours after fertilization. The newly hatched larvae reared for 33 days grow up to 12.10 mm in total length and developed to the jevenile. When larvae length attained about 8.0 mm, jaw bones were more rapidly ossified than vertebrae and cranium.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.150-168
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• 1991

A practical procedure for the ultimate compressive strength-based safety and reliability assessment of the double skin upper deck structure is described. The external compressive stress acting on the upper deck structure which is due to the still water and wave-induced sagging moment is approximately estimated by using the existing rule of classification society. The ultimate compressive stress of double skin structure under the action of sagging moment is analyzed by using idealized structural unit method. Here an idealized plate element subjected to uniaxial load is formulated by idealizing the nonlinear behaviour of the actual element taking account of the initial imperfections in the form of initial deflection and welding residual stress. The interaction effect between the local and global failure in the structure is also taken into consideration. The accuracy of the present method is verified comparing with the present solution and the existing numerical and experimental results for unit member and welded box columns. The safety of the structure is evaluated using the concept of conventional central safety factor and the reliability assessment is made by using Cornel's MVFOSM method. The present procedure is then applied to upper deck structure of double skin product oil carrier. The influence of the initial imperfections and the yield stress of the material on the safety and reliability of the structure is investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.898-904
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• 2021

This experimental study aims to investigate the use of a wet electrostatic precipitator as a post-treatment device to satisfy the strict emission regulations for sulfur oxides and particulate matter (PM). The inlet/outlet of a wet electrostatic precipitator was installed in a funnel using a marine four-stroke diesel engine (STX-MAN B&W) consuming marine heavy fuel oil (HFO) with a sulfur content of about 2.1%. Measurements were then obtained at the outlet of the wet electrostatic precipitator; an optical measuring instrument (OPA-102), and the weight concentration measurement method (Method 5 Isokinetic Train) were used for the PM measurements and the Fourier transform infrared (FT-IR; DX-4000) approach was used for the sulfur oxide measurements. The experimenst were conducted by varying the engine load from 50%, to 75% and 100%; it was noted that the PM reduction efficiency was a high at about 94 to 98% under all load conditions. Additionally, during the process of lowering the exhaust gas temperature in the quenching zone of the wet electrostatic precipitator, the sulfur dioxide (SO₂) values reduced because of the cleaning water, and the reduction rate was confirmed to be 55% to 81% depending on the engine load.