• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.575-582
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• 2011

A cleaning blade is an attachment installed in the toner cartridge of a laser printer for removing the residual toner from an organic photo-conductive drum. There have been many studies on the performance and life of the rubber blade. We focus on optimally designing the blade shape parameters to minimize the maximum stress of the blade while satisfying design constraints on the cleaning performance and part interference. The blade is optimally designed using a design of experiments, meta-models and an optimization algorithm implemented in PIAnO (process integration, automation, and optimization), a commercial PIDO (process integration and design optimization) tool. We integrate the CAE tools necessary for the structural analysis of the cleaning blade, automate the analysis procedure, and optimize the solution using PIAnO. We decreased the maximum stress by 32.6% in comparison with that of the initial design.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.307-313
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• 2013

This study was carried out to investigate the residual characteristics of fungicide azoxystrobin and difenoconazole in Prunus mume fruits, and establish pre-harvest residue limits (PHRL) based on dissipation and biological half-lives of fungicide residues. The fungicides were sprayed onto the crop at recommended dosage once and 3 times in 7 days interval, respectively. The samples were harvested at 0, 1, 2, 4, 6, 8, 10, 12 and 14 days after treatment. These residual pesticides were extracted with QuEChERS method, clean-up with $NH_2$ SPE cartridge, and residues were analyzed by HPLC/DAD and GLC/ECD, respectively. Method quantitative limits (MQL) of azoxystrobin were 0.03 mg $kg^{-1}$ and of difenoconazole were 0.006 mg $kg^{-1}$. Average recovery were $93.2{\pm}2.49%$, $85.5{\pm}1.97%$ for azoxystrobin at fortification levels at 0.3 and 1.5 mg $kg^{-1}$, and $100.8{\pm}6.74%$, $87.6{\pm}9.92%$ for difenoconazole at fortification levels at 0.06 and 0.3 mg $kg^{-1}$, respectively. The biological half-lives of azoxystrobin were 5.9 and 5.2 days at recommended dosage once and 3 times in 7 days interval, respectively. The biological half-lives of difenoconazole were 9.3 and 8.0 days at recommended dosage once and 3 times in 7 days interval, respectively. The PHRL of azoxystrobin and difenoconazole were recommended as 5.32 and 1.64 mg $kg^{-1}$ for 10 days before harvest, respectively.

• Journal of Electrochemical Science and Technology
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• v.9 no.3
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• pp.220-228
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• 2018

This study introduced a carbon-free electrode for $Li-O_2$ cells with the aim of suppressing the side reactions activated by carbon material. Micro-particles of poly(3,4-ethylenedioxythiophene) (PEDOT), a conducting polymer, were used as the base material for the air electrode of $Li-O_2$cells. The PEDOT micro-particles were treated with $H_2SO_4$ to improve their electronic conductivity, and LiBr and CsBr were used as the redox mediators to facilitate the dissociation of there action products in the electrode and reduce the over-potential of the $Li-O_2$ cells. The capacity of the electrode employing PEDOT micro-particles was significantly enhanced via $H_2SO_4$ treatment, which is attributed to the increased electronic conductivity. The considerable capacity enhancement and relatively low over-potential of the electrode employing $H_2SO_4$-treated PEDOT micro-particles indicate that the treated PEDOT micro-particles can act as reaction sites and provide storage space for the reaction products. The cyclic performance of the electrode employing $H_2SO_4$-treated PEDOT micro-particles was superior to that of a carbon electrode. The results of the Fourier-transform infrared spectroscopic analysis showed that the accumulation of residual reaction products during cycling was significantly reduced by introducing the carbon-free electrode based on $H_2SO_4$-treated PEDOT micro-particles, compared with that of the carbon electrode. The cycle life was improved owing to the effect of the redox mediators. The refore, the use of the carbon -free electrode combined with redox mediators could realize excellent cyclic performance and low over-potential simultaneously.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.138-146
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• 2008

The chemical compositions, cell wall biopolymers and non-isothermal behavior of the stem biomass of Nicotiana Tabacum originated from tobacco industry were investigated in depth. On a weight basis, the contents of total ash and total sugar are 19.1% and 20.7% respectively. Lignin content was around 3% of tobacco stem biomass while pectin was over 7%. The holo-cellulose content in cell wall biopolymer was around 13% and the $\alpha$-cellulose constitutes 60% of the total holo-cellulose. The thermal behavior of stem biomass showed different patterns depending on either inert (nitrogen) or oxidizing (air) atmospheric condition. In the air atmosphere, the rapid thermal decompositions at around $473^{\circ}C$ and $581^{\circ}C$ were recorded as the peaks in DTG curve, while the peaks were not shown in the nitrogen atmosphere condition. The thermal analysis of the freeze dried soluble obtained from hot water extraction of tobacco stem biomass showed that the rapid thermal decomposition at around $581^{\circ}C$ in the air atmosphere was due to the residual char originated from the soluble fraction. The distinct difference in thermal decomposition between hemicellulose and cellulose were easily found in the DTG curve obtained in the nitrogen atmosphere.

• Current Research on Agriculture and Life Sciences
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• v.29
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• pp.11-19
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• 2011

This research gives weight to establish practical improvement based on analysis of the landscape ecological character and value to realize the importance of small wetland and stream in cultivated areas functioning as a residual landscape element in rural landscape and to deal with ecological depression effectively. The results of summary are as follows. 1) The results of landscape ecological character analysis of wetlands biotop in total of 7 sites, for example, size of surface in site 5 was widely formed about $10,600m^2$, which was assessed satisfactory in terms of slope of waterfront, width of hedgerow, vegetation condition of composition and so on. Also, The number of flexibility showed 2 in site 8-1, the highest, and morphological diversity showed 1.47, the highest. 2) The results of problem analysis of wetland biotop, most of wetlands are analyzed that the width of hedgerow was below 1m. Also, the 4 wetlands in site 8 are appeared that hard to live slope vegetation in there because of slope of waterfronts are above $45^{\circ}$. 3) The results of landscape ecological character analysis of stream in total of 6 sites, for example, width of waterfront in site 4 showed 55m, the widest, and investigated consist of natural ingredients such as soil, rock, gravel. However, width of waterfront in site 2-2 showed 4m, the narrowest, and inclined angle of slope was formed a right angle. 4) The results of problem analysis of stream, width of waterfront hedgerow in site 2-1 showed about 5m, which was very narrower than width of waterfront, and toxic chemicals discharged from near cultivated area without any filtering. Also, all areas of site 2-2 was formed concrete, and was assessed dissatisfactory in terms of capacity of nature purification, flood control, habitat living space because of straight stream. 5) Based on the result above landscape ecological character and problem analysis, main improvement guidelines are set in terms of shape, vegetation, topography in case of wetlands, and which are set in terms of vertical, horizontal structure in case of stream.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.185-200
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• 2022

The risk of various hazardous substances in aquatic environment comprises not only the concentration of substances in the environmental medium but also their accumulation in fish through complex food web and the health risks to humans through the fish. In Korea, the monitoring of residual toxicant in aquatic ecosystems began in 2016 following the enforcement of the Acts on registration and evaluation for the management of chemicals used in daily life (consumer chemical products), and attention has been paid to potentially hazardous substances attributed to them. Recently, studies have been carried out to investigate the distribution of these hazardous substances in the ecosystem and calculate their emission factors. These include the accumulation and transport of substances, such as detergents, dyes, fragrances, cosmetics, and disinfectants, within trophic levels. This study summarizes the results of recently published research on the inflow and distribution of hazardous substances from consumer chemical products to the aquatic environment and presents the scientific implication. Based on studies on aquatic environment monitoring techniques, this study suggests research directions for monitoring the residual concentration and distribution of harmful chemical substances in aquatic ecosystems. In particular, this study introduces the directions for research on trophic position analysis using compound specific isotope analysis and trophic magnification factors, which are needed to fulfill the contemporary requirements of selecting target fish based on the survey of major fish that inhabit domestic waters and assessment of associated health risk. In addition, this study provides suggestions for future biota monitoring and chemical research in Korea.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.151-164
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• 2002

Genetic variance and covariance components of the linear traits and the ordered categorical traits, that are usually observed as dichotomous or polychotomous outcomes, were simultaneously estimated in a multivariate threshold animal model with concepts of arbitrary underlying liability scales with Bayesian inference via Gibbs sampling algorithms. A multivariate threshold animal model in this study can be allowed in any combination of missing traits with assuming correlation among the traits considered. Gibbs sampling algorithms as a hierarchical Bayesian inference were used to get reliable point estimates to which marginal posterior means of parameters were assumed. Main point of this study is that the underlying values for the observations on the categorical traits sampled at previous round of iteration and the observations on the continuous traits can be considered to sample the underlying values for categorical data and continuous data with missing at current cycle (see appendix). This study also showed that the underlying variables for missing categorical data should be generated with taking into account for the correlated traits to satisfy the fully conditional posterior distributions of parameters although some of papers (Wang et al., 1997; VanTassell et al., 1998) presented that only the residual effects of missing traits were generated in same situation. In present study, Gibbs samplers for making the fully Bayesian inferences for unknown parameters of interests are played rolls with methodologies to enable the any combinations of the linear and categorical traits with missing observations. Moreover, two kinds of constraints to guarantee identifiability for the arbitrary underlying variables are shown with keeping the fully conditional posterior distributions of those parameters. Numerical example for a threshold animal model included the maternal and permanent environmental effects on a multiple ordered categorical trait as calving ease, a binary trait as non-return rate, and the other normally distributed trait, birth weight, is provided with simulation study.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1825-1832
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• 2000

Column experiments were conducted by using soil columns, to investigate feasibility and efficiency of in-situ ozone enhanced remediation for diesel-contaminated soil. The injection of gaseous ozone into soil column revealed the enhanced decomposition of ozone due to the catalytic reaction between ozone and metal (e.g., Fe, Mn etc.) oxides as evidenced by as much as 25 times shorter half-life of ozone in a sand packed column than in a glass beads packed column. Substantial retardation in the transport of and the consumption of ozone were observed in the diesel contaminated field soil and sand packed columns. After 16 hrs ozonation, 80% of the initial mass of diesel (as diesel range organic) concentration of $800{\pm}50mg/kg$, was removed under the conditions of the flow rate of 50mL/min and $6mg-O_3/min$. Whereas, less than 30% of diesel was removed in the case of air injection. Analysis of the residual TPH(total petroleum hydrocarbon) and selected 8 aliphatics of diesel compounds in the inlet and the outlet of the column confirmed that diesel nonselectively reacted with ozone and then shifted to lower carbon numbered molecules. Water content also was found to be an important parameter in employing ozone to the hydrocarbon-contaminated soil.

• Current Research on Agriculture and Life Sciences
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• v.16
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• pp.15-23
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• 1998

This experiment did comparison and analysis that protected soil particle migration have affect on function of the filter and therefore fall function of the filter. Results obtained are as follows: 1.High water head makes to be much movement of fine sand and out flow of particle to the outside. The filter have large opening size that reached stability an early stage, but much fine sand is washed away. If the velocity turns fast and becomes small, blocking phenomenon is remarkable nearby the filter-sand interface. 2. The movement of fine sand that effect on function of filter depend on opening size and change of water head. Under the same condition, USCE filter and USSPL filter is reached earlier than other filter that is stability of stage, because it's opening size is large. 3. Residual quantity of fine sand migration was largly come out in order of USSPL, USCE, USBR, Newton & Hurley, Bertram filter. 4. The time required to stability of flow was taken less in order of Bertram, Newton & Hurley, USBR, USSPL, USCE filter and coefficient of permeability was highly come out in order of USBR, Bertram, Newton & Hurley, USSPL, USCE filter. 5. It proved that USCE and USSPL is suitable for the filter criteria.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.130-140
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• 2014

Recently, some of the previous studies reported that tolclofos-methyl is still exist in ginseng cultivated soil, even though it is has been banned for ginseng. Therefore, the current study was aimed to examine the levels of absorption and translocation of tolclofos-methyl from ginseng cultivated soil to ginseng root and leaf stem for the period of 1 year. For this study, ginseng plants were transplanted in pots and treated with $5.0mg\;kg^{-1}$ of tolclofos-methyl (50% WP). At the end of each interval periods (every three months) the samples (soil, roots and leaf stems) were collected and analyzed the absorption and translocation levels of tolclofos-methyl using gas chromatography and mass spectrometry (GC-MS). The limit of quantitation of tolclofos-methyl was found to be $0.02mg\;kg^{-1}$ and 70.0~120.0% recovery was obtained with coefficient of variation of less than 10% regardless of sample types. In this study, a considerable amount of translocation of tolclofos-methyl residues were found in soil (4.28 to $0.06mg\;kg^{-1}$), root (7.09 to $1.54mg\;kg^{-1}$) and leaf stem (0.79 to $0.69mg\;kg^{-1}$). The results show that the tolclofos-methyl was absorbted and translocated from ginseng cultivated soil to ginseng root and ginseng leaf stem and found to be decreased time-coursely. Secondly, we were also analyzed soil, root and leaf stems samples from Hongcheon, Cheorwon, Punggi and Geumsan by GC-MS/MS (172 pesticides), LC-MS/MS (74 pesticides). In this study, 43 different pesticides were detected ($0.01{\sim}7.56mg\;kg^{-1}$) in soil, root and leaf stem. Further, tolclofos-methyl was detected 4 times separately in root sample alone which is less ($0.01{\sim}0.05mg\;kg^{-1}$) than their maximum residual limit (MRL) in ginseng. Consequently, the results from both studies indicate the residues of tolclofos-methyl found in ginseng cultivated soil and ginseng ensuring their safety level. Moreover, long-term evaluations are needed in order to protect the soil as well as ginseng free from tolclofos-methyl residues.