• Korean Chemical Engineering Research
• /
• v.52 no.6
• /
• pp.807-813
• /
• 2014

The Ag-impregnated activated carbon was produced from bamboo activated carbon by soaking method of silver nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. Soaking conditions are the variation of silver nitrate solution concentration (0.002~0.1 mol/L) and soaking time (maximum 24 h). The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20{\sim}850^{\circ}C$) and NO gas partial pressure (0.1~1.8 kPa). As results, Ag amounts are saturated within 2h, Ag amounts increased 1.95 mg Ag/g (0.2%)~ 88.70 mg Ag/g (8.87%) with the concentration of silver nitrate solution in the range of 0.002~0.1 mol/L. The specific volume and surface area of bamboo activated carbon of impregnated with 0.2% silver were maximum, but decreased with increasing Ag amounts of activated carbon due to pore blocking. In NO reaction, the reaction rate of impregnated bamboo activated carbon was retarded as compare with that of bamboo activated carbon. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.69l[BA(Ag)] and 80.5 kJ/mol[BA], 66.4 kJ/mol[BA(Ag)], respectively.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.7
• /
• pp.692-698
• /
• 2020

This paper examines the effects of a multi-stage pilot split injection strategy on combustion and exhaust emission factors in a single-cylinder diesel engine. One analysis noted that in the single-injection condition, the maximum in-cylinder pressure and rate of heat release were highest. The pilot injection quantity was evenly divided, showing a tendency to decrease as the number of injections increased. In another injection condition, when the multi-stage pilot split injection strategy was applied, IMEP, engine torque, and combustion increased. The COV_IMEP was greatest with the lowest combustion efficiency. The combustion ability was poor. In a single injection condition, the O₂ concentration in the exhaust gas was the lowest and the CO₂ was the highest. When the multi-stage split injection strategy was applied, the low temperature combustion process proceeded, and the oxidation rate of CO₂ decreased while the emission level increased. In a single injection condition in which a locally rich mixture was formed, the HC emission level showed the highest results. A 55.6% reduction of NOx emission occurred under a three-stage pilot injection condition while conducting a multi-stage pilot split injection strategy.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.3
• /
• pp.144-149
• /
• 2016

The metal-impregnated activated carbon was produced from bamboo activated carbon by soaking method of metal nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use as de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20^{\circ}C{\sim}850^{\circ}C$) and NO gas partial pressure (0.1 kPa~1.8 kPa). As results, the specific volume and surface area of bamboo activated carbon impregnated with copper were decreased with increasing Cu amounts of activated carbon. In NO reaction, the reaction rate of Cu impregnated bamboo activated carbon[BA(Cu)] was promoted to compare with that of bamboo activated carbon[BA]. But the reaction rate of Ag impregnated bamboo activated carbon[BA(Ag)] was retarded. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.92[BA(Cu)], and 80.5 kJ/mol[BA], 48.5 kJ/mol[BA(Cu)], 66.4 kJ/mol[BA(Ag)], respectively.

• Journal of Food Hygiene and Safety
• /
• v.13 no.4
• /
• pp.406-411
• /
• 1998

Representive cured products such as ham and sausage produced in Korea were purchased at retail and cooked using heating tools such as a gas range (GR), an electric range (ER) and electric range after boiled (BE). Changes of N-nitrosamine (NA), nitrate and nitrite in the cured meats containing< $2.0\;\mu\textrm{g}/kg$ of N-nitrosodimethylamine (NDMA) were checked and analyzed during their cooking process. Contents of nitrate and nitrite in ham products prior to cooking were 2.0 and 1.8 mg/kg, respectively; their contents in regular hams were slightly increased, but those of nitrate in press hams were decreased while those of nitrite were increased during its cooking process. Their contents in sausage products were 1.8 and 0.9 mg/kg; those of nitrate were decreased, while nitrite were slightly increased during its cooking process. NDMA detected only NA in all the collected cured products. Changes of NDMA, regardless of cooking methods, tend to drastically increase in all samples after their cooking; Its contents were increased by average 6.0~70.7 times in the GR samples, by average 2.4~39.2 times in the ER samples and by average 7.0~56.3 times in the BE samples. Virtually, the fact that all of this nitrosamine appeared to arise by the action of precursor such as NOx was produced during the cooking of cured products.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.3
• /
• pp.639-647
• /
• 2011

In this paper, we introduce a design methodology of data-centroid Radial Basis Function neural networks with extended polynomial function. The two underlying design mechanisms of such networks involve K-means clustering method and Particle Swarm Optimization(PSO). The proposed algorithm is based on K-means clustering method for efficient processing of data and the optimization of model was carried out using PSO. In this paper, as the connection weight of RBF neural networks, we are able to use four types of polynomials such as simplified, linear, quadratic, and modified quadratic. Using K-means clustering, the center values of Gaussian function as activation function are selected. And the PSO-based RBF neural networks results in a structurally optimized structure and comes with a higher level of flexibility than the one encountered in the conventional RBF neural networks. The PSO-based design procedure being applied at each node of RBF neural networks leads to the selection of preferred parameters with specific local characteristics (such as the number of input variables, a specific set of input variables, and the distribution constant value in activation function) available within the RBF neural networks. To evaluate the performance of the proposed data-centroid RBF neural network with extended polynomial function, the model is experimented with using the nonlinear process data(2-Dimensional synthetic data and Mackey-Glass time series process data) and the Machine Learning dataset(NOx emission process data in gas turbine plant, Automobile Miles per Gallon(MPG) data, and Boston housing data). For the characteristic analysis of the given entire dataset with non-linearity as well as the efficient construction and evaluation of the dynamic network model, the partition of the given entire dataset distinguishes between two cases of Division I(training dataset and testing dataset) and Division II(training dataset, validation dataset, and testing dataset). A comparative analysis shows that the proposed RBF neural networks produces model with higher accuracy as well as more superb predictive capability than other intelligent models presented previously.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.4
• /
• pp.1307-1319
• /
• 2018

As interests in the air pollution increases, many kinds of researches are underway on the reduction of air pollutants. The removal of nitrogen oxides from the emission gas of diesel vehicles using urea solution has shown a great effect. The quality of urea solution is strictly defined by domestic law, but the increase of impurities in urea solution reduces the effect of reducing nitrogen oxides. Therefore, in this study, the change of physical properties of urea solution was analyzed after heating the urea solution for a certain temperature and time. Also, the changes of physical properties of urea solution were analyzed according to kinds of storage container and temperature for storing the urea solution. After heating the urea solution for a certain period of time, the biuret content in urea solution increased and the content of urea decreased. As the urea content decreased, both density and refractive index decreased. In the storage stability test carried out at a constant temperature with iron and PET containers, no change in physical properties was observed.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.25 no.2
• /
• pp.108-116
• /
• 2023

Recently, the concentration of fine dust causative substances (NOx, VOC, etc.) in the atmosphere has increased, resulting in high concentrations of tropospheric ozone (O3) and increased damage to crops. This study aimed to analyze the impact of high concentrations of ozone gas on the initial growth of rice plants and investigate the relationship between ozone damage resistance and anthocyanin biosynthesis. To achieve this, rice plants were exposed to elevated levels of ozone g as using an ozone chamber, and subsequent measurements were taken to assess changes in growth, the percentage of damaged leaves, and the anthocyanin content. The results revealed that varieties with a higher proportion of damaged leaves exhibited a relative increase in anthocyanin biosynthesis following ozone exposure. Notably, detrimental effects on growth, such as decreased biomass, were mitigated. Additionally, Anthocyanin biosynthesis genes in rice were listed by selecting homologous genes from Arabidopsis and Maize. The expression of OsF3H2, OsFLS1 and OsLDOX3 was induced during ozone treatment. This result is expected to contribute to the study of the protection mechanism of plants from ozone damage.

• Journal of Korea Port Economic Association
• /
• v.39 no.3
• /
• pp.47-60
• /
• 2023

A thorough inventory of ship emissions, particularly ship's emission of in-port area is necessary to identify significant sources of exhaust gases such as NOx, SOx, PM, and CO₂ and trends in emission levels over time, and reduce their serious effects on the environment and human health. Therefore, the goal of this study is to assess the volume of emissions from ships in Mokpo port, which serves as a gateway to the southwest coast of Korea, using a bottom-up methodology and data from the automatic identification system (AIS) and the Korean Port Management Information System (Port-MIS). In this work, an analysis of ship movement utilizing AIS data and an actual set of data on ship specification were gathered. By examining ship movement using AIS data, We also proposed a new approach for identifying cruising/maneuvering mode. Finally, the results were classified by ship operating mode, by exhaust gas, by ship type, and by berth, which provides a thorough and in-depth analysis of the air pollution caused by ships in Mokpo port.

• Journal of Korean Society of Transportation
• /
• v.17 no.4
• /
• pp.99-110
• /
• 1999

With a growing awareness, transportation is the maior source of urban air pollution. Planners and policy-makers are strongly urged to care the impacts of transportation management strategies on environment. Since transport-related air Pollution can be regarded as negative externalities of transport, it is indispensable to evaluate chanties in air quality which seems to occur when proposed transport measures are implemented. In addition, transport measures should be integrated in a set of combined Paradigm regarding transport and environment. Based on the integrated Paradigm between transportation demand management(TDM) and environmental planning, the main focus is given to apply environment cost internalizing measures to the short-term congestion management Program(SCMP) in Seoul, that has been developed in 1998 by Seoul Development Institute. Three modules are analyzed: without and/or with ￦500, ￦1000 emission plus gas tax, respectively. From the empirical applications on Seoul city, one of the most exemplary findings in SCMP program is that, emission plus gas tax can be a very useful measure to reduce vehicular emissions by targeting major Pollutants differently, rather than by dealing with pollutants collectively. Further research that provides (1)showing the spatial variation of pollution levels along the intersections, (2)more developing combined Paradigm between transport, land use, and environment, (3)using environmental road capacity rather than Physical-aspects of road capacity, and (4)continuing R&D on air quality constrained TDM, can contribute significantly to applications of the real and efficient environment-constrained transportation planning.

• Korean Chemical Engineering Research
• /
• v.51 no.3
• /
• pp.313-318
• /
• 2013

In order to investigate the effect of $V_2O_5$ loading of $V_2O_5-WO_3/TiO_2$ catalyst on the NO reduction and the formation of $N_2O$, the experimental study was carried out in a differential reactor using the powder catalyst. The NO reduction and the ammonia oxidation were, respectively, investigated over the catalysts compose of $V_2O_5$ content (1~8 wt%) based on the fixed composition of $WO_3$ (9 wt%) on $TiO_2$ powder. $V_2O_5-WO_3/TiO_2$ catalysts had the NO reduction activity even under the temperature of $200^{\circ}C$. However, the lowest temperature for NO reduction activity more than 99.9% to treat NO concentration of 700 ppm appeared at 340 with very limited temperature window in the case of 1 wt% $V_2O_5$ catalyst. And the temperature shifted to lower one as well as the temperature window was widen as the $V_2O_5$ content of the catalyst increased, and finally reached at the activation temperature ranged $220{\sim}340^{\circ}C$ in the case of 6 wt% $V_2O_5$ catalyst. The catalyst of 8 wt% $V_2O_5$ content presented lower activity than that of 8 wt% $V_2O_5$ content over the full temperature range. NO reduction activity decreased as the $V_2O_5$ content of the catalyst increased above $340^{\circ}C$. The active site for NO reduction over $V_2O_5-WO_3/TiO_2$ catalysts was mainly related with $V_2O_5$ particles sustained as the bare surface with relevant size which should be not so large to stimulate $N_2O$ formation at high temperature over $320^{\circ}C$ according to the ammonia oxidation. Currently, $V_2O_5-WO_3/TiO_2$ catalysts were operated in the temperature ranged $350{\sim}450^{\circ}C$ to treat NOx in the effluent gas of industrial plants. However, in order to save the energy and to reduce the secondary pollutant $N_2O$ in the high temperature process, the using of $V_2O_5-WO_3/TiO_2$ catalyst of content $V_2O_5$ was recommended as the low temperature catalyst which was suitable for low temperature operation ranged $250{\sim}320^{\circ}C$.