• 한국유가공학회:학술대회논문집
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• 2002.04a
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• pp.59-60
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• 2002

Edible films such as wax coatings, sugar and chocolate covers, and sausage casings, have been used in food applications for years$^{(1)}$ However, interest in edible films and biodegradable polymers has been renewed due to concerns about the environment, a need to reduce the quantity of disposable packaging, and demand by the consumer for higher quality food products. Edible films can function as secondary packaging materials to enhance food quality and reduce the amount of traditional packaging needed. For example, edible films can serve to enhance food quality by acting as moisture and gas barriers, thus, providing protection to a food product after the primary packaging is opened. Edible films are not meant to replace synthetic packaging materials; instead, they provide the potential as food packagings where traditional synthetic or biodegradable plastics cannot function. For instance, edible films can be used as convenient soluble pouches containing single-servings for products such as instant noodles and soup/seasoning combination. In the food industry, they can be used as ingredient delivery systems for delivering pre-measured ingredients during processing. Edible films also can provide the food processors with a variety of new opportunities for product development and processing. Depends on materials of edible films, they also can be sources of nutritional supplements. Especially, whey proteins have excellent amino acid balance while some edible films resources lack adequate amount of certain amino acids, for example, soy protein is low in methionine and wheat flour is low in lysine$^{(2)}$. Whey proteins have a surplus of the essential amino acid lysine, threonine, methionine and isoleucine. Thus, the idea of using whey protein-based films to individually pack cereal products, which often deficient in these amino acids, become very attractive$^{(3)}$. Whey is a by-product of cheese manufacturing and much of annual production is not utilized$^{(4)}$. Development of edible films from whey protein is one of the ways to recover whey from dairy industry waste. Whey proteins as raw materials of film production can be obtained at inexpensive cost. I hypothesize that it is possible to make whey protein-based edible films with improved moisture barrier properties without significantly altering other properties by producing whey protein/lipid emulsion films and these films will be suitable far food applications. The fellowing are the specific otjectives of this research: 1. Develop whey protein/lipid emulsion edible films and determine their microstructures, barrier (moisture and oxygen) and mechanical (tensile strength and elongation) properties. 2. Study the nature of interactions involved in the formation and stability of the films. 3. Investigate thermal properties, heat sealability, and sealing properties of the films. 4. Demonstrate suitability of their application in foods as packaging materials. Methodologies were developed to produce edible films from whey protein isolate (WPI) and concentrate (WPC), and film-forming procedure was optimized. Lipids, butter fat (BF) and candelilla wax (CW), were added into film-forming solutions to produce whey protein/lipid emulsion edible films. Significant reduction in water vapor and oxygen permeabilities of the films could be achieved upon addition of BF and CW. Mechanical properties were also influenced by the lipid type. Microstructures of the films accounted for the differences in their barrier and mechanical properties. Studies with bond-dissociating agents indicated that disulfide and hydrogen bonds, cooperatively, were the primary forces involved in the formation and stability of whey protein/lipid emulsion films. Contribution of hydrophobic interactions was secondary. Thermal properties of the films were studied using differential scanning calorimetry, and the results were used to optimize heat-sealing conditions for the films. Electron spectroscopy for chemical analysis (ESCA) was used to study the nature of the interfacial interaction of sealed films. All films were heat sealable and showed good seal strengths while the plasticizer type influenced optimum heat-sealing temperatures of the films, 130$^{\circ}$C for sorbitol-plasticized WPI films and 110$^{\circ}$C for glycerol-plasticized WPI films. ESCA spectra showed that the main interactions responsible for the heat-sealed joint of whey protein-based edible films were hydrogen bonds and covalent bonds involving C-0-H and N-C components. Finally, solubility in water, moisture contents, moisture sorption isotherms and sensory attributes (using a trained sensory panel) of the films were determined. Solubility was influenced primarily by the plasticizer in the films, and the higher the plasticizer content, the greater was the solubility of the films in water. Moisture contents of the films showed a strong relationship with moisture sorption isotherm properties of the films. Lower moisture content of the films resulted in lower equilibrium moisture contents at all aw levels. Sensory evaluation of the films revealed that no distinctive odor existed in WPI films. All films tested showed slight sweetness and adhesiveness. Films with lipids were scored as being opaque while films without lipids were scored to be clear. Whey protein/lipid emulsion edible films may be suitable for packaging of powder mix and should be suitable for packaging of non-hygroscopic foods$^{(5,6,7,8,)}$.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.304-309
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• 2007

Soybean is useful source of protein, especially in Asia. But soybean needs heat inactivation or fermentation process before consumption, since it contains the toxic lectin and various protease inhibitors. Therefore, production of soybean boiling-waste liquor (SBWL) as a byproduct is inevitable. In this study, the chemical composition of SBWL and the optimization of culture conditions for Bacillus pumilus JB-1, a selected strain for functional chungkuk-jang fermentation, using SBWL were investigated. The SBWL contains 88% water, 9.5% free sugar, 1.6% crude protein, 0.3% crude fat, 0.1% crude fiber and 2.1% ash, respectively. The contents of total polyphenol, total flavonoids and free amino acid in SBWL were 55%, 76%, and 30% of those of raw soybean, respectively. Culture conditions for B. pumilus JB-1 in SBWL were optimized. The 1/10-diluted, 0.1 % of $(NH_4)_2SO_4$ added SBWL without pH adjustment and carbon source addition was cultured at $37^{\circ}C$ for 48 h with agitation (120 rpm). The 0.5% of inoculation was enough. The large scale fermentation in 5-L jar fermentor showed that the SBWL is a good resource for production of chungkuk-jang starter and functional ingredients.

• Journal of Korean Society of societal Security
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• v.4 no.2
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• pp.73-78
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• 2011

In order to resolve the problem of change in global climate which is worsening as days go by and to preemptively cope with strengthened restriction on carbon emission, the government enacted 'Framework Act on Low Carbon Green Growth' in 2010 and selected green technology and green industry as new national growth engines. For this reason, the necessity to use the un-utilized waste heat across the whole industrial system has become an issue, and studies on and applications of recycling in the agricultural and fishery fields such as cultivation of tropical crops and flatfishes by utilizing the waste heat and thermal effluent generated by large industrial complexes including power plants are being actively carried out. In this study, we looked into the domestic and overseas examples of having utilized waste heat abandoned in the form of power plant thermal effluent, and carried out economic efficiency evaluation of sturgeon aquaculture utilizing thermal effluent of Yeongwol LNG Combined Cycle Power Plant in Gangwon-do. In this analysis, we analyzed the economic efficiency of a model business plan divided into three steps, starting from a small scale in order to minimize the investment risk and financial burden, which is then gradually expanded. The business operation period was assumed to be 10 years (2012~2021), and the NVP (Net Present Value) and economic efficiency (B/C) for the operation period (10 years) were estimated for different loan size by dividing the size of external loan by stage into 80% and 40% based on the basic statistics secured through a site survey. Through the result of analysis, we can see that reducing the size of the external loan is an important factor in securing greater economic efficiency as, while the B/C is 1.79 in the case the external loan is 80% of the total investment, it is presumed to be improved to 1.81 when the loan is 40%. As the findings of this study showed that the economic efficiency of sturgeon aquaculture utilizing thermal effluent of power plant can be secured, it is presumed that regional development project items with high added value can be derived though this, and, in addition, this study will greatly contribute to reinforcement of the capability of local governments to cope with climate change.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.379-387
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• 1999

During the past several decades, electricity generating plant increased with remarkable rapidity in Korea. Recently the increase has been much more rapid as the rate of industrialization has accelerated. Construction of nuclear power plants in coastal areas inevitably caused the perturbation of critical coastal habitats and thus influenced marine algal species composition. Particularly, an increase in the building of nuclear power plants led the amounts of heat discharged to increase exponentially. As far as the effects of cooling water and thermal discharges are concerned, benthic marine algae are likely to be vulnerable to a discharge. Heated effluents from nuclear power plants, with the temperature rises of 7~12$^{\circ}C$ under normal operating and design conditions, are discharged through the discharge canal and into natural water bodies. It is clear that the characteristic marine algal community is developed in the area affected by the thermal discharges; i.e. low species richness and low species diversity. Nevertheless, it is worthwhile to note that elevated temperatures exert differential effects depending on the algal populations. Benthic marine algae grown at the discharge canal can be regarded as warm tolerant species. 35 species (4 blue-green, 9 green, 8 brown and 14 red algae) of marine algae occurred more than 20eye frequency at discharge canal of three nuclear power plants in the east coast during 1992 ~ 1998 and thus can be categorized as warm tolerant species in Korea. To minimize the ecological impacts of waste heat on benthic marine algae, it is recommended that, in the future, nuclear power plants will have to employ some form of closed-cycle cooling for the condensers.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.2
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• pp.92-103
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• 1993

A sunday system with a horizontal bin-type composter was constructed and operated to evaluate its composting performance for four days for each test in October, 1992. A sundry system is one of popular systems for composting livestock manure, of which main benefit is to utilize unlimited, clean, and free solar radiation. A rectangular concrete bin(composter) with dimension of 300cm(length) X90cm(width) X60cm(height) was bedded alternatively with four lanes of aeration pipes and heating pipes, and was insulated at three walls with 50mm styrofoam. Each aeration pipe of a diameter of 25mm had 4mm perforated holes at every 15cm longitudinally, and supplied air of about 2m$^3$/min to the composter to maintain aerobic condition . A stirrer rotating at 1 rpm made one round trip every 20 minutes on the conveying chain along the the length of the composter. Five tests (Test 1~Test 5) were implemented to evaluate the composting effectiveness of a sundry system with a horizontal bin-type composter. Treatments of two levels of the mixture ratio of swine manure and paper sludge cakes(manure : paper sludge cakes= 1 : 4 and 1 : 2) and two levels of the water content(W/C ; 70% and 50%) were made to test the significance of the physicochemical properties for decomposition of the mixture materials. Temperature, C/N ratio, water content, microbial activity of the composting materials were taken measurements to evaluate its performance with the lapse of composting time for tests. A small-scale sundry system with a bin-type composter did not appear to be an appropriate system for composting livestock manure. Since heat generation by the composting materials could not overcome heat loss due to areation in a small-scale composter, a proper thermal enviroment could not be maintained to propagate massively thermopilic microorganism relatively in a short period of time. Different from the result of Chol et al.(1992) 6), a temperature variation of the composting materials did not show the peak clearly and C/N ratio didn't lower with time as expected. Mesophilic microoragnism seemed to play an important role for decomposition of the mixture materials. A sundry system with a bin-type composter may be good for a large-scale livestock farm household which may produce enough animal manure. Therefore a decision should be made very carefully to choose a system for composting livestock waste.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.514-520
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• 2014

In this study, the production potential of alternative coagulant ($Al_2(SO_4)_3$ solution) having the identical coagulation activity with respect to the commercial coagulant was investigated. The raw material of alternative coagulant was a spent catalyst including aluminium (waste activated alumina) generated in the manufacturing process of the polymer. The alternative coagulant was produced through a series of processes: 1) intense heat and grinding, 2) chemical polymerization and substitution with $H_2SO_4$ solution, 3) dissolution and dilution and 4) settling and separation. To determine the optimal operating conditions in the lab-scale autoclave and dissolver, the content of $Al_2O_3$ in alternative coagulant was analyzed according to changes of the purity of sulfuric acid, reaction temperature, injection ratio of sulfuric acid and water in the dissolver. The results showed that the alternative coagulant having the $Al_2O_3$ content of 7~8% was produced under the optimal conditions such as $H_2SO_4$ purity of 50%, reaction temperature of $120^{\circ}C$, injection ratio of $H_2SO_4$ of 5 times and injection ratio of water of 2.3 times in dissolver. In order to evaluate the coagulation activity of the alternative coagulant, the Jar-test was conducted to the effluent in aerobic reactor. As a result, in both cases of Al/P mole of 1.5 and 2.0, the coagulation activity of the alternative coagulant was higher than that of the existing commercial coagulant. When the production costs were compared between the alternative and commercial coagulant through economic analysis, the production cost reduction of about 50% was available in the case of the alternative coagulant. In addition, it was identified that the alternative coagulant could be applied at field wastewater treatment plant without environmental problem through ecological toxicity testing.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.13-29
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• 2016

In this study, we analyzed the causes of major faults in the biogas plant through the case of gas engine failure when cogenerating electricity and heat using biogas as a fuel in the actual sewage treatment plant and suggested countermeasures. Hydrogen sulfide in the biogas entering the biogas engine and water caused by intermittent malfunction of the water removal system caused intercooler corrosion in the biogas engine. In addition, the siloxane in the biogas forms a silicate compound with silicon dioxide, which causes scratches and wear of the piston surface and the inner wall of the cylinder liner. The substances attached to the combustion chamber and the exhaust system were analyzed to be combined with hydrogen sulfide and other impurities. It is believed that hydrogen sulfide was supplied to the desulfurization plant for a long period of time because of the high content of hydrogen sulfide (more than 50ppm) in the biogas and the hydrogen sulfide was introduced into the engine due to the decrease of the removal efficiency due to the breakthrough point of the activated carbon in the desulfurization plant. In addition, the hydrogen sulfide degrades the function of the activated carbon for siloxane removal of the adsorption column, which is considered to be caused by the introduction of unremoved siloxane waste into the engine, resulting in various types of engine failure. Therefore, hydrogen sulfide, siloxane, and water can be regarded as the main causes of the failure of the biogas engine. Among them, hydrogen sulfide reacts with other materials causing failure and can be regarded as a substance having a great influence on the pretreatment process. As a result, optimization of $H_2S$ removal method seems to be an essential measure for stable operation of the biogas engine.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.479-482
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• 2008

Since late of 2000, KIER has developed a novel pyrolysis process for production of fuel oils from polymer wastes. It could have been possible due to large-scale funding of the Resource Recycling R&D Center. The target was to develop an uncatalyzed, continuous and automatic process producing oils that can be used as a fuel for small-scale industrial boilers. The process development has proceeded in three stages bench-scale unit, pilot plant and demonstration plant. As a result, the demonstration plant having capacity of 3,000 tons/year has been constructed and is currently under test operation for optimization of operation conditions. The process consisted of four parts ; feeding system, cracking reactor, refining system and others. Raw materials were pretreated via shredding and classifying to remove minerals, water, etc. There were 3 kind of products, oils(80%), gas(15%), carbonic residue(5%). The main products i.e. oils were gasoline and diesel. The calorific value of gas has been found to be about 18,000kcal/$m^3$ which is similar to petroleum gas and shows that it could be used as a process fuel. Key technologies adopted in the process are 1) Recirculation of feed for rapid melting and enhancement of fluidity for automatic control of system, 2) Tubular reactor specially-designed for heavy heat flux and prevention of coking, 3)Recirculation of heavy fraction for prevention of wax formation, and 4) continuous removal & re-reaction of sludge for high yield of main product (oil) and minimization of residue. The advantages of the process are full automation, continuous operation, no requirement of catalyst, minimization of coking and sludge problems, maximizing the product(fuel oil) yield and purity, low initial investment and operation costs and environment- friendly process. In this presentation, background of pyrolysis technology development, the details of KIER pyrolysis process flow, key technologies and the performances of the process will be discussed in detail.

• Journal of the Korea Furniture Society
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• v.19 no.6
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• pp.475-486
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• 2008

In this study, fire-retardant chemicals were melt with mixed composition ratios of dibasic ammonium phosphate and each half of boric acid and borax in hot water, in which hammer-milled chips were immersed to increase swelling of waste particleboards. Also, fire-retardant treated particles from sawn lumber chip and recycled particleboard chip were composed in ratio of 70:30 in core layer to improve boards' properties. Retention ratio of fire-retardant chemicals for the particles for face layer was high due to high specific surface area, and that of sawn lumber chips was somewhat higher than that of recycled particleboard chips. The mixture of particles from sawn lumber chips and recycled PB of 70:30 in weight ratio exceeded bending strength of 100 $kgf/cm^2$. It seemed that the relatively greater portions of dibasic ammonium phosphate affected adversely to dimensional stability, however fire-retardants treatment resulted in distinct effect lowering formaldehyde emission such as $E_0$ type(0.5mg/$\ell$ or less) in KS F 3104. In fire-retardancy, the recycled boards with a mixed ratio of dibasic ammonium phosphate to boric acid borax(50:50 mixture) of 70% to 30% in weight satisfied fire-retardancy 3rd grade in KS F 2271, and also this composition from cone calorimeter test met same standard grade figuring total heat release of 4.6MJ/$m^2$.

• Journal of Animal Environmental Science
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• v.5 no.3
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• pp.189-196
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• 1999

Anaerobic digestion is a naturally occuring microbial process involving the decomposition of organic materials such as livestock manure. This study explores the effect of the operating conditions, HRT (Hydraulic Retention Time) and feeding frequency on treatment efficiency for digestion of pig slurry, which has been one of most difficult organic waste for proper treatment in livestock production industry in Korea at the present time. The pilot-scale CSTR of 5 m3 in volume was designed. manufactured, and operated at the temperature of 35$\pm$1$^{\circ}C$. The digester was designed to hydraulically stir for complete mixing and to supply heat from the water bath to maintain mesophilic temperature. The HRT of the digester for Test 1 and Test 2, and Test 3 was set for 17 days and 13 days respectively and pig slurry was fed once a day with 300$\ell$ each for Test 1 and Test 3, while twice with 150$\ell$each for Test 2. Test 2 showed better performance by increase of 4% in VS removal efficiency and 5% in biogas production rate. This is mainly attributed to smaller temperature drop by feeding frequently with half amount, which eventually led to lesser impact on anaerobic mocrobes in the digester. Test 2 maintained optimum pH 7.8 which uplifted the activaton of sulfur-reduction bacteria, alkalinity of around 4,000mg/$\ell$, VA of over 3,000mg/$\ell$ for whole period of experiment. Further research may require to provide the practical operation strategy of anaerobic treatment system for treatment of pig slurry.