• Journal of Power System Engineering
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• v.10 no.3
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• pp.5-10
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• 2006

In a conventional and lean operating engine, the state of mixture is very important in the combustion and emission characteristics. Lean operation is known to decrease the formation while maintaining a good fuel economy, but the unstable operation due to misfire and erratic combustion prevents engines from being operated at very lean mixtures, so both combustion rates and exhaust emission formation need to be satisfied comparably. In this study, it is designed and experimented the modified engine, and analyzed the combustion and exhaust emission according to the change of engine speed and with adding ozone. The conclusions were drawn out and enumerated as follows. 1. At the experimental result of automobile diesel engine, it has been verified that the formation of particulate matter(PM) gas is able to be lower with the addition of optimum quantities of ozone. 2. Carbon monoxide(CO) was formed by the lack of oxygen and the thermal dissociation in the combustion process. Therefore, with the change of swirl valve's position and addition of oxygen and ozone, CO formation was decreased by the increasing of excessive O2, but it was increased by the temperature of combustion gas growing higher. As a result of the two effects, CO formation was decreased in this study. 3. Hydrocarbon(HC) was formed by the lack of O2, and the flow of mixture in cylinder. According to opening of the swirl valve and adding the oxygen and ozone, hydrocarbon gas was decreased by 20%, 9%, and 27.5%, respectively. 4. Nitric oxides($NO_x$) was strongly affected by the combustion gas temperature. As a result of respectively experimental conditions, $NO_x$ formation was increased about 20% due to (be the) high(er) combustion gas temperature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.2
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• pp.51-57
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• 1985

In the design of civil engineering structures, the designers are invariably faced to the uncertainties and the randomness of the design parameters such as material properties and loads. Even when the structures are built, the actual geometries of the structures are also subject to their random variations from their nominal design values. Thus, the reliability of a structure in terms of these uncertainties and variations becomes a matter of great concern to the structural designers. This study employs the First Order Second Moment Method to evluate numerically the reliability of a simple tension member and discusses the influence on the final failure probability of that structure due to: 1) use of equivalent normal distribution in place of non-normal distribution, 2) linearization of non linear limit state equation. A discussion is also made on the necessity of fundamental studies on the distrubution characteristics of the strength of locally produced construction materials and those of the loads frequently encountered in the structural design.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.75-81
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• 1996

The dry matter (DM) disappearance and ruminal solubility of calcium (Ca), phosphorus (P), magnesium (Mg) and potassium (K) in eight Philippine forages were studied. The forages were: paragrass (Brachiaria mutica (Forsk.) Stapf), stargrass (Cynodon plectostachyum Pilger), napiergrass (Pennisetum purpureum Schumach), clopo (Calopogonium mucconoides Desv.), centrocema (Centrocema pubescens Benth.), gliricidia (Gliricidia sepium (Jacq.) Walp.), leucaena (Leucaena leucocephala (Lam.) de Wit.) and sesbania (Sesbania grandiflora (L.) Poir. Nylon bags with samples were incubated for 0, 3, 6, 12, 24, 48 and 72 h in rumen cannulated sheep. The 0-h bags were washed with deionized water. For the 0-h samples, 20.4, 17.2, 50.7, 52.2 and 80.1% of the DM, Ca, P, Mg and K was solubilized, respectively. At 3-h incubation period, DM disappearance was 10 percentage units higher than that of 0-h incubation whereas mineral disappearance increased by 43, 21, 30 and 13% for Ca, P, Mg and K, respectively. At 72-h incubation period, greater proportion of DM, Ca, especially in P, Mg and K was solubilized with a value of 73.8, 71.5, 85.6, 91.4 and 98.2%, respectively. The average particulate passage rate obtained in the present study was 1.9%/h where as the range of disappearance rates of various mineral elements were : 0.4 to 1.2%/h for Ca, 0.1 to 1.6%/h for P, 0.7 to 2%/h for Mg and 0.1 to 2%/h for K. The effective ruminal solubilization (ERS) of the macrominerals was calculated where particulate passage rate and disappearance rate of the various elements were included in the equation. The ERS of Ca, P, Mg and K was 50.0, 72.6, 83.9 and 94.5%, respectively. Species differences (p<0.05) on the various mineral solubilities were also observed. This study shows that ruminal solubility of macrominerals in selected Philippine forages is K > Mg > P > Ca.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.368-378
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• 2005

Inorganic matters originated from stone quarries and manufacturing plants could alter the ecological characteristics of adjacent aquatic systems, especially the structure and function of benthic macroinvertebrate community. In such situation, the locality of stone quarry and the quantity of inorganic matters would be important factors that determined the disturbing strength to the benthic macroinvertebrate community. Locality patterns of stone quarries were classified into 3 types in relation to the stream ecosystem; stream-proximity, upstream-inclusion and tributary-inclusion type. In the result of species:abundance analysis, stone quarry B (upstream-inclusion type) showed geometric distribution, while others showed broken-stick distribution pattern. The benthic macroinvertebrate communities closer to stone quarries showed smaller species numbers and standing crops among all types of stone quarries. However the values of species evenness index were not seriously different between controls and directly affected sites. These results indicated that the effect of inorganic disturbance would differ from those of organic pollution that induced the highly dominant state occupied by tolerant species. Number of occurred species, standing crops, community indices and biotic indices indicated that the community of upstream-inclusion type was the most seriously damaged from the inorganic disturbance, and the community would be very simple and unstable. Tributary-inclusion stone quarry heavily damaged to tributary system in biologically, but influence to the main stream seemed to be depended on the scale of main stream. Among 3 types of stone quarry localities, stream-proximity type induced the least damages to benthic macroinvertebrate community, though the degrees of damage were different along with distances between stream and stone quarry.

• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.537-546
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• 2013

In the Seoul Metropolitan Area(SMA) photochemical air pollutants, nitrogenic compound and particulate matters have increased substantially due to mobile sources, power plants and so on. Therefore 'Special Act on Seoul Metropolitan Air Quality Improvement' was enacted on 2003 in order to improve air quality in the SMA. According to the Special Act, Central and local government have developed the state implementation plan(SIP) to reduce air pollutant emissions from various local sources. One of the key elements of the SIP development is the air quality modeling since modeling results can be used to establish emissions control strategies as well as to demonstrate attainment of air quality goals for ozone, particulate matter, and so on. Air quality modeling, therefore, can be usefully utilized to investigate the effects of government's efforts according to control strategies or measures. Using the air quality model, we can determine whether the implementation plan should be revised or not. A number of questions, however, has been raised concerning accuracy, consistency and transparency of modeling results because if we do not trust modeling results, all the measures dependent on modeling becomes in vain. So, without dealing with these questions, we can not guarantee the reliability and utilizability of air quality modeling results. In this study, we tried to establish standard methodology for air quality modeling in order to ensure consistency and transparency of modeling results used in the development and evaluation of national air policy. For this purpose, we established air quality modeling guideline to provide or recommend modeling procedures, vertical and horizontal domains, input data of meteorological and air quality modeling and so on.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.153-159
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• 2007

Nano-Particles are influenced on the environmental protection and human health. The relationships between transient vehicle operation and nano-particle emissions are not well-known, especially for diesel passenger vehicles with DPF. In this study, a diesel passenger vehicle was measured on condition of DPF regeneration and no regeneration on a chassis dynamometer test bench. The particulate matter (PM) emission from this vehicle was measured by its number, size and mass measurement. The mass of the total PM was evaluated with the standard gravimetric measurement method while the total number and size concentrations were measured on a NEDC driving cycle using Condensation Particle Counter (CPC) and EEPS. Total number concentration by CPC was $1.5{\times}10^{1l}N/km$, which was 20% of result by EEPS. This means about 80% of total particle emission is consist of volatile and small-sized particles(<22nm). During regeneration, particle emission was $6.2{\times}10^{12}N/km$, was emitted 400 times compared with the emission before regeneration. As for the particle size of $22{\sim}100nm$ was emitted mainly, showing peak value of near 40nm in size. This means regeneration decreased the mean size of particles. Regarding regeneration, PM showed no change while the particle number showed about 6 times difference between before and after regeneration. It seems that the regeneration influences on particle number emissions are related to DPF-fill state and filtration efficiency.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.625-632
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• 2003

In this study, the effects of two types of reward methods in cooperative learning were investigated upon students' achievement, learning motivation, perceptions of learning environment and perceptions of reward methods. Seventh graders (N=61) were selected from a co-ed middle school in Seoul, and were taught about 'three states of matter', 'motion of molecules' and 'change of state and thermal energy' for 14 class hours. Reward methods were classified into task-oriented reward and performance-oriented reward. The results revealed that high-level students performed better in the task-oriented reward group, and low-level students performed better in the performance-reward group for the 'application' subcategory of the achievement test. The scores of attention and relevance in learning motivation and task orientation, involvement, and order and organization in perceptions of learning environment test were significantly higher in the task-oriented reward group than those in the performance-oriented reward group.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.120.1-120.1
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• 2012

The Lunar Reconnaissance Orbiter (LRO) launched on June 16, 2009 has six experiments including of the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) onboard. The CRaTER instrument characterizes the radiation environment to be experienced by humans during future lunar missions. The CRaTER instrument measures the effects of ionizing energy loss in matter specifically in silicon solid-state detectors due to penetrating solar energetic protons (SEP) and galactic cosmic rays (GCRs) after interactions with tissue-equivalent plastic (TEP), a synthetic analog of human tissue. The CRaTER instrument houses a compact and highly precise microdosimeter. It measures dose rates below one micro-Rad/sec in silicon in lunar radiation environment. Forbush decrease (FD) event is the sudden decrease of GCR flux. We use the data of cosmic ray and dose rates observed by the CRaTER instrument. We also use the CME list of STEREO SECCHI inner, outer coronagraph and the interplanetary CME data of the ACE/MAG instrument.We examine the origins and the characteristics of the FD-like events in lunar radiation environment. We also compare these events with the FD events on the Earth. We find that whenever the FD events are recorded at ground Neutron Monitor stations, the FD-like events also occur on the lunar environments. The flux variation amplitude of FD-like events on the Moon is approximately two times larger than that of FD events on the Earth. We compare time profiles of GCR flux with of the dose rate of FD-like events in the lunar environment. We figure out that the distinct FD-like events correspond to dose rate events in the CRaTER on lunar environment during the event period.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.255-266
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• 2019

This paper examines the ink on paper technique that is being used in the animation works by the Canadian filmmaker Michēle Cournoyner from the National Film Board of Canada. It also discusses how in her animated film "Soif"(2013) this technique has been applied to compose the narrative significance and symbols through the use of metamorphosis as a form of artistic expression. Cournoyner had used the ink of paper technique as a means to abandon realistic representations of movement, and in "Soif" through expressive use of metamorphosis, portrayed changes of images in character and object not through chronological order of narrative flow, but through the body of the female character, which had been represented by the improvisation of the ink on paper technique in order to express the surrealistic and unconscious state of mind in animation. Also, the use of Surrealist automatism had been incorporated to evoke the film towards a form of abstract and metaphysical expression, which in terms of expression and technique connects with the character in the animation to give emphasis to its relevancy with the subject matter of the work.

• Asian Journal of Atmospheric Environment
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• v.10 no.2
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• pp.67-79
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• 2016

The forecasting of air pollution is an important and popular topic in environmental engineering. Due to health impacts caused by unacceptable particulate matter (PM) levels, it has become one of the greatest concerns in metropolitan cities like Karaj City in Iran. In this study, the concentration of $PM_{2.5}$ was predicted by applying a multilayer percepteron (MLP) neural network, a radial basis function (RBF) neural network and a Markov chain model. Two months of hourly data including temperature, NO, $NO_2$, $NO_x$, CO, $SO_2$ and $PM_{10}$ were used as inputs to the artificial neural networks. From 1,488 data, 1,300 of data was used to train the models and the rest of the data were applied to test the models. The results of using artificial neural networks indicated that the models performed well in predicting $PM_{2.5}$ concentrations. The application of a Markov chain described the probable occurrences of unhealthy hours. The MLP neural network with two hidden layers including 19 neurons in the first layer and 16 neurons in the second layer provided the best results. The coefficient of determination ($R^2$), Index of Agreement (IA) and Efficiency (E) between the observed and the predicted data using an MLP neural network were 0.92, 0.93 and 0.981, respectively. In the MLP neural network, the MBE was 0.0546 which indicates the adequacy of the model. In the RBF neural network, increasing the number of neurons to 1,488 caused the RMSE to decline from 7.88 to 0.00 and caused $R^2$ to reach 0.93. In the Markov chain model the absolute error was 0.014 which indicated an acceptable accuracy and precision. We concluded the probability of occurrence state duration and transition of $PM_{2.5}$ pollution is predictable using a Markov chain method.