• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.391-400
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• 2008

Odor management is significantly concerned with sustainable livestock production because odor nuisance is a primary cause for complaint to neighbors. This study was conducted to measure the concentration of odorous compounds, odor intensity, and odor offensiveness at unit process in animal waste treatment facility combined composting and methane fermentation process by an instrumental analysis and direct olfactory method. Ammonia, sulfur-containing compounds, and volatile fatty acid were analyzed at each process units and boundary area in summer and winter, respectively. Higher concentration of odorants occurred in the summer than in the winter due to high ambient temperature. The maximum concentration of odorants was detected in composting pile when mixed manure was being turned followed by inlet, curing, outlet, and screen & packing process. Highest concentration of detected odorous compounds was ammonia ranging from 3.4 to 224.7 ppm. Among the sulfur-containing compounds measured, hydrogen sulfide was a maximum level of 2.3 ppm and most of them exceeded reported odor detection thresholds. Acetic acid was the largest proportion of VFA generated, reaching a maximum of 51 to 89%, followed by propionic and butyric acid at 1.9 to 35% and 1.8 to 15%, respectively. Malodor assessment by a human panel appeared a similar tendency in instrumental analysis data. Odor quotient for predicting major odor-causing compounds was calculated by dividing concentrations measured in process units by odor detection thresholds. In the composting process, hydrogen sulfide, ammonia, dimethyl sulfide, and methyl mercaptan were deeply associated with odor-causing compounds, while the major malodor compounds in the inlet process were methyl mercaptan, hydrogen sulfide, and butyric acid.

• Resources Recycling
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• v.24 no.3
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• pp.59-65
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• 2015

Recycling of vulcanized rubber products is a serious problem in the world. A quantity of generated waste tires becomes much more and more because of increasing demands on automobiles, resulted in the cause of serious secondary pollution by sulfur component that is crosslinked to incineration or landfill. In addition, crosslinked surfur is used to interfere with the binding of the raw material rubber. In this study, we analyzed the degree of devulcanization by the chemical devulcanization. Devulcanization ratio of the samples were systematically analysed by variables such as time and temperature. In addition, the effect of swelling method as a pre-treatment process was also measured. A rubber specimen was deepened in a organic 2-buthanol solutions during various times of 1 ~ 5 hrs at 100, 150, $200^{\circ}C$ respectively, then to calculate the crosslink density and the number average molecular weight by using a parallel expansion process, which showed devulcanization degree of analyzed samples quantitatively. Also, the mechanical properties were measured with the samples prepared by using a hot press.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.294-301
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• 2017

In this study, we found the optimal manufacturing conditions of livestock manure sludge RDF with the oil-drying method. We performed oil evaporation, oil drying and pelletizing of the sludge to evaluate the value of the product (sludge RDF), and measured the performance of the product using calorimeter and PXRF equipment. Also, we conducted the calorie comparison test between sludge RDF manufactured in this study and wood RDF generally used in the field. Experimental results showed that 30g of the sludge treated by vegetable oil at $130^{\circ}C$ for 25 minutes were the optimal conditions to make the sludge RDF (considering the aspects of eco-friendly and mass production). The caloric value of the sludge RDF manufactured in this study was 5211kcal/kg which is higher than that of wood RDF used widely in the market. Finally, PXRF results showed sludge RDF contains no heavy metals with the exception of sulfur. Therefore, we recommend more study about the sulfur control process for future development of the industrial manufacturing process.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.809-818
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• 2019

Since January 1, 2020, the International Maritime Organization (IMO) has put in place strong regulations to reduce air pollution caused by ships by lowing the upper limit of ship fuel oil sulfur content from 3.5% to 0.5% for ships passing through all sea areas around the world. Although it is important to reduce air pollutants by using fuel oil with low sulfur content, reducing the amount of energy waste through the economic operation of a ship can also help reduce air pollutants. Ships can follow designated routes accurately even under the influence of noise using autopilot systems. However, regardless of their quality, the performance of these systems is af ected by noise; heading angles with added measurement noise from the gyroscope are input into the autopilot system and degrade its performance. A technique to solve these problems reduces noise effects through the application of a Kalman filter, which is widely used in condition estimation. This method, however, cannot completely eliminate the effects of noise. Therefore, to further improve noise removal performances, in this study we propose a better denoising method than the Kalman filter technique by applying a multi-layer perceptron (MLP) in forward direction motion and a Kalman Filter in rotation motion. Simulations show that the proposed method improves forward direction motion by preventing the malfunction of a rudder more so than merely using a Kalman Filter.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.4
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• pp.162-168
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• 2016

The aim was to investigate the effect of reducing the odorous and complex odor released during the decomposition of food wastes using effective microorganism (EM) as a function of time at $20^{\circ}C$ and $35^{\circ}C$. The variation of total microbial counts and dominant species counts in EM and leachate produced during food wastes decomposition was also observed. In general, the cumulative concentration of sulfur compounds ($H_2S$, $CH_3SH$) and complex odor released during food wastes decomposition increased with increasing elapsed time. The nitrogen compounds ($NH_3$, trimethyl amine), however, was not observed in all samples. The addition of EM in food wastes resulted in the reduction of concentration of sulfur compounds and complex odor, in spite of the increase of $CH_3CHO$ concentration. The dominant microbial species detected in EM were Lactobacillus species(Lactobacillus rhamnosus and Lactobacillus casei). In the leachate produced during food wastes decomposition, however, the various microbial community alternative to that detected in EM was observed. The EM could be potentially useful as a tools for reducing odor induced from the food waste decomposition process.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.359-369
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• 2011

The study was carried out to investigate the quality characteristics of pellets manufactured with adding soybean oil, waste soybean oil, ozonized soybean oil and ozonized waste soybean oil to Larix kaemferi Carr sawdust. The characteristics of pellet included moisture contents, heating value, ash contents, apparent densities, durabilities, absorption ratio and elementary analysis. Moisture contents were shown 7.66~9.48% which satisfied the first grade (less than 10%) of quality standard of wood pellets announced by Korea Forest Research Institute. The heating value of the manufactured wood pellets in this study exceeded the first grade of quality standard (more than 4,300 kcal/kg) and it appeared that the pellets manufactured with adding oils and ozonized oils had more heating value than the control pellets. Ash contents 0.34~0.42% also passed the first grade (less than 0.7%) of quality standard and apparent densities were adequate for the first grade (640 kg/$m^3$) on the quality standard. Durabilities of the pellets manufactured with adding soybean oil and ozonized waste soybean oil were shown over the first grade (97.5 kg/$m^3$) of quality standard. In the general results of durabilities, the pellets manufactured with additives had better values than the control pellets. After 24 hours absorption ratio experiment, absorption ratio of pellets manufactured with additives also appeared much lower moisture absorption than the control pellets and they still had the same results after 5days absorption ratio experiment. Elementary analysis of the sulfur content was satisfied the first grade (less than 0.05%) of quality standard of wood pellets and the nitrogen content was also adequate for the first grade (less than 0.3%) of quality standard of wood pellets.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.1
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• pp.62-69
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• 2008

There has been a recent trend in Korea that treatments for combustible wastes among municipal solid waste (MSW) by those methods, such as incineration and landfill are restricted as much as possible and Mechanical Biological Treatment (MBT) are encouraged actively in order to promote resource recovery. To build and operate properly these facilities, the physicochemical characteristics of MSW should be analyzed precisely beforehand. In particular, designing a crusher or separator properly which is the main process in MBT facilities of MSW. require the information on the size distribution characteristics of MSW, but they are nor sufficient in the qualities and quantities yet as of now. Accordingly, this study aims to evaluate size distribution characteristics of MSW and its physicochemical characteristics by size. The samples of MSW were collected from detached dwelling area, apartment area, business area, and commercial area of A city in Korea. According to the result of analysis, paper records 29.78~60.02% by wet weight basis, so it was the most regardless of the regions where the wastes were generated. And in terms of element analysis, Carbon(C) was 34.77~44.39%, the largest friction, and Oxygen(O) was the next occupying 19.46~33.71%. As indices of RDFs, Chlorine(Cl) was 0.39~0.83%, so it was less than the standard, 2.0%(by dry weight basis); moreover, Sulfur(S) did not exceed the standard, 0.6%, either. In the size distribution of MSW, waste fraction ranging 50~80mm in diameter was the most in combustible waste while 30~50mm was in incombustible waste.

• International Journal of Concrete Structures and Materials
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• v.2 no.1
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• pp.15-19
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• 2008

The most typical capping method for concrete structures is a sulfur-mortar compound capping, provided it satisfied the standard criterion set forth by ASTM C 617, but this conventional bonded-type method has many problems. It exhibits relatively the smaller unreliable value of the strength of high-strength concrete due to the differences of elasticity and strength between the cylinder and the cap, and manifests poor serviceability such as dangerous working tasks or a waste of the working time. To prevent these problems, unbonded-type capping methods have taken the place of the conventional methods in recent years. One of the popular methods is the use of synthetic rubber like a neoprene pad. Serious problems still remain in this method, which include the consideration of its chemical characteristics in consideration of the selection, the safekeeping and the economy of the pads. Moreover, the synthetic rubber pads cannot be used in concrete cylinder with strength greater than 80 MPa according to ASTM C 1231-00. New 'sand-capping method' presented in this study, can be applicable to the compressive strength evaluation of the high strength concrete in the range of $70{\sim}100\;MPa$. This new method has better simplicity and reliability than those of existing 'sand-box', because usual materials such as standard sand and simply-devised apparatus are used for the capping system. The statistical analysis of the test results revealed that the new sand-capping method exhibited the smallest deviation and dispersion, attesting for its much better reliability than other methods specified in ASTM C 1231/1231M.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.2
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• pp.99-107
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• 2009

This paper reviews the current status of mercury research on exposure and contamination, mercury emissions, emission limits and control technologies, long-range transport and deposition research, and mercury management policy in Korea. According to a monitoring of the Ministry of Environment and the Ministry of Health and Welfare, blood mercury levels among Koreans are $5{\sim}8$ times higher than those of U.S. and Germany. The most dominant source of exposure to mercury is through dietary intake. Emissions of mercury from coal-fired power plants are estimated 8.93 ton/year in 2004. Emissions of mercury from other important sources, such as waste incineration, steel and cement manufacturing and non-ferrous metal smelting operations are to be further investigated. A study on long-range transport of mercury suggests that the dry deposition flux over the Yellow Sea was much greater than those for other oceans. As a whole, the amounts of wet depositions of nitrogen and sulfur were 1.9 and 1.5 times larger than the amounts of dry depositions in each species, respectively. Substantial influence from China caused by high emissions in East China and westerly wind was possibly suggested. However, the influence from nitrogen emission in Korea was also confirmed. Korean Government has already adopted stringent emission limits on mercury for incinerators and boilers in 2005. However, emission limits for coal-fired power plants and non-ferrous metal smelters are rather relaxed. As the above mentioned two sources can be two most important sources of mercury emissions, control strategy for those sources are to be considered.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.519-525
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• 2010

Ethanol was used as reductant to remove $NO_x$ over Ag/$Al_2O_3$ catalyst via SCR from stationary emission source. Among the tested hydrocarbon reductants, ethanol showed highest de-$NO_x$ performance over the Ag/$Al_2O_3$ catalyst. De-$NO_x$ efficiency of about 83% was obtained in the condition of GHSV 20,000 $hr^{-1}$, $NO_x$ 200 ppm, CO 200 ppm, $O_2$ 13%, $H_2O$ 5% and mole ratio of ethanol/$NO_x$ = 2 between temperature of $300^{\circ}C$ and $400^{\circ}C$. While $SO_2$ presence in the $NO_x$ exhaust suppressed the catalytic activity, catalyst with acid (0.7% $H_2SO_4$) treatment of catalyst showed higher catalytic activity, where In-Situ DRIFT showed S presence over catalyst surface was increased after acid treatment of catalyst. From in-situ DRIFT and SCR results, it was concluded that sulfur presence over the surface of Ag/$Al_2O_3$ catalyst was the dominant factor to control the de-$NO_x$ reaction yield via HC-SCR from the exhausted gas including $SO_2$.