• Journal of Environmental Science International
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• v.24 no.11
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• pp.1485-1491
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• 2015

There are two treatment processes that are currently applied to ships are the biological treatment process using the activated sludge and the electrochemical treatment. However, neither of them are able to remove both nitrogen and phosphorus due to their limited ability to remove organic matters, which are main causes of the red tide. This study was conducted to identify the characteristics of nitrogen removal factors from manure wastewater by replacing the final settling tank in SBR (Sequencing Batch Reactor) process and applying immersion type hollow fiber membrane. SBR process is known to have an advantage of the least land requirement in special environment such as in ship and the immersion type hollow fiber membrane is more stable in water quality change. As the result, the average in the cases of DO (Dissolved Oxygen) is 2.9(0. 6~3.9) mg/L which was determined to be the denitrifying microorganism activity in anaerobic conditions. The average in the cases of ORP (Oxidation Reduction Potential) is 98.4~237.3 mV which was determined to be the termination of nitrification since the inflection point was formed on the ORP curve due to decrease in the stirring treatment after the aeration, same as in the cases of DO. Little or no variation in the pH was determined to have positive effect on the nitrification. T-N (Total Nitrigen) removal efficiencies of the finally treated water were 71.4%, 72.3% and 66.5% in relatively average figures, thus was not a distinct prominence. In being applied in ships in the future, the operating conditions and structure improvements are deemed necessary since the MEPC (Marine Environment Protection Committee). 227(64) ship sewage nitrogen is less than the standard of 20 Qi/Qe mg/L or the removal rate of 70%.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.1-8
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• 2004

In this study, the change of the current in the coastal zone before and after the construction of Jeju new harbor was predicted by using the numerical model, which uses Hardy-Cross method. The numerical model was carried out for the present state, before the construction, and the state after the construction, and for the wave direction the NNW direction for winter and NE direction for summer were tested so that the seasonal change may be considered. The computation result shows that a large amount of the wave induced current was occurred when there were high waves coming in from NNW direction before and after the construction. Also, before the construction a longshore current occurred moving from the west to the east at the new harbor construction site so that it formed a rip current in the Hwabuk-dong front sea. And also, after the construction, the tip current produced changed into nearshore circulating current and a small circulating current appeared at the harbor entrance. On the other hand, at Samyang 4each, which is 3.0km away from the new harbor in the NE direction, shows that there was a longshore current occurred from the west to the east, which is in the opposite direction the new harbor, and the effect on the new harbor by sediment transport at Samyang beach is thought to be very small.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.2
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• pp.62-75
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• 1986

An experimental investigation of the machining characteristics such as cutt- ing resistance, surface roughness and tool wear in turning the test pieces of SM45C steel with both coated and uncoated carbide tool tips under various cutting conditions was conducted. Also a specially designed simple vibration damping device was experimentally evaluated for its effectiveness on machined surface roughness and a vibration test was conducted to confirm its ability to reduce the amplitude. Based on these tests finding, the following conclusions are made; 1. The cutting resistance($\textrm{p}_{1}$) increases as the depth of cut(d) increases at fixed feed rate(f) over the cutting speed(v) range of 43-226 m/min and p decreses about 18% average when V is increased for fixed d and f. At V= 226m/min, $\textrm{p}_{1}$/for A, C tips are about the same level but $\textrm{p}_{1}$ for B tip is 15% less than A, C tips. 2. The specific cutting resistance(Ks) at V=226 m/min was derived for A, B, C tips respectively and the value of Ks for B rip is about 20% less than A, C tips. 3. The surface roughness(Ra) improves significantly as the cutting speed(V) is increased and this effect was greater when V>100 m/min. On the other hand, Ra deteriorates as the feed rate(f) is increased and this trend was accelerated when f>0.3 mm/rev. With regard to the difference of Ra values among A, B, C tips, at V=226m/min, d=0.4mm, and f=0.31-0.61mm/rev, Ra values for B.C tips are about 17% less than tip A. 4. The experimental tool wear equations were derived for A, B, C tips and from these equations, the tool life($\textrm{T}_{\textrm{L}}$) baced on the I.S.O. criteria was calculated to be $\textrm{T}_{\textrm{L}}$<$\textrm{T}_{\textrm{LB}}$<$\textrm{T}_{\textrm{LC}}$ for both flank wear($\textrm{V}_{\textrm{B}}$) and boundary wear($\textrm{V}_{\textrm{N}}$). Hence, the coated tips are superior to the uncoated tip and tip C is considered to be the best. 5. The cutting resistance may be slightly reduced and the surface rounghness improved when the damper is used especially when V>100 m/min. Therefore this damping device is considered to be effective and practical. The experimental surface roughness equations were also derived. Based on the vibration test, it is established that the surface roughness improvement was the result of amplitude reduction made possible by the damper.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.3
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• pp.149-156
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• 2011

Golgi SNAP receptor complex 1 (GS28) has been implicated in vesicular transport between intra-Golgi networks and between endoplasmic reticulum (ER) and Golgi. Additional role(s) of GS28 within cells have not been well characterized. We observed decreased expression of GS28 in rat ischemic hippocampus. In this study, we examined the role of GS28 and its molecular mechanisms in neuronal (SK-N-SH) cell death induced by hydrogen peroxide ($H_2O_2$). GS28 siRNA-transfected cells treated with $H_2O_2$ showed a significant increase in cytotoxicity under glutathione (GSH)-depleted conditions after pretreatment with buthionine sulfoximine, which corresponded to an increase of intracellular reactive oxygen species (ROS) in the cells. Pretreatment of GS28 siRNA-transfected cells with p38 chemical inhibitor significantly inhibited cytotoxicity; we also observed that p38 was activated in the cells by immunoblot analysis. We confirmed the role of p38 MAPK in cotransfected cells with GS28 siRNA and p38 siRNA in the cell viability assay, flow cytometry, and immunoblot. Involvement of apoptotic or autophagic processes in the cells was not shown in the cell viability, flow cytometry, and immunoblot analyses. However, pretreatment of the cells with necrostatin-1 completely inhibited $H_2O_2$-induced cytotoxicity, ROS generation, and p38 activation, indicating that the cell death is necroptotic. Collectively these data imply that $H_2O_2$ induces necroptotic cell death in the GS28 siRNA-transfected cells and that the necroptotic signals are mediated by sequential activations in RIP1/p38/ROS. Taken together, these results indicate that GS28 has a protective role in $H_2O_2$-induced necroptosis via inhibition of p38 MAPK in GSH-depleted neuronal cells.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.647-653
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• 2010

The objectives of this research are to evaluate and compare the oxygen transfer coefficients($K_{La}$) in both a general bubbles reactor and a micro-nano bubbles reactor for effective operation in sewage treatment plants, and to understand the effect on microbial kinetic parameters of biomass growth for optimal biological treatment in sewage treatment plants when the micro-nano bubbles reactor is applied. Oxygen transfer coefficients($K_{La}$) of tap water and effluent of primary clarifier were determined. The oxygen transfer coefficients of the tap water for the general bubbles reactor and micro-nano bubbles reactor were found to be 0.28 $hr^{-1}$ and 2.50 $hr^{-1}$, respectively. The oxygen transfer coefficients of the effluent of the primary clarifier for the general bubbles reactor and micro-nano bubbles reactor were found be to 0.15 $hr^{-1}$ and 0.91 $hr^{-1}$, respectively. In order to figure out kinetic parameters of biomass growth for the general bubbles reactor and micro-nano bubbles reactor, oxygen uptake rates(OURs) in the saturated effluent of the primary clarifier were measured with the general bubbles reactor and micro-nano bubbles reactor. The OURs of in the saturated effluent of the primary clarifier with the general bubbles reactor and micro-nano bubbles reactor were 0.0294 mg $O_2/L{\cdot}hr$ and 0.0465 mg $O_2/L{\cdot}hr$, respectively. The higher micro-nano bubbles reactor's oxygen transfer coefficient increases the OURs. In addition, the maximum readily biodegradable substrate utilization rates($K_{ms}$) for the general bubbles reactor and micro-nano bubbles reactor were 3.41 mg COD utilized/mg active VSS day and 7.07 mg COD utilized/mg active VSS day, respectively. The maximum specific biomass growth rates for heterotrophic biomass(${\mu}_{max}$) were calculated by both values of yield for heterotrophic biomass($Y_H$) and the maximum readily biodegradable substrate utilization rates($K_{ms}$). The values of ${\mu}_{max}$ for the general bubbles reactor and micro-nano bubbles reactor were 1.62 $day^{-1}$ and 3.36 $day^{-1}$, respectively. The reported results show that the micro-nano bubbles reactor increased air-liquid contact area. This method could remove dissolved organic matters and nutrients efficiently and effectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.456-462
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• 2012

In the new changing scenario, the goal of agriculture is shifting from traditional to sustainable and environment-friendly agriculture. Therefore, in this experiment, we analyzed economic efficiency of two methods of rice cultivation i.e. new cultural method and conventional method, at farmers' fields. In the new cultural method, cost of materials and machines (rice-transplanting and sowing machine) was found 245% higher than the conventional method. Depreciation of cost and working hours were also higher in the new cultural method by 1.9 and 1.1 time, respectively. However, cost of seeds and seedbed soil were 44.0% and 49.2% lower and total material cost was 4.4% lower than the conventional method. In the new cultural method, overall working cost of nursery raising and transplanting per 10a was 229.8% higher than the conventional method. However, in spite of high input cost, yield of rice in new cultural method was higher by 6.7% than the conventional method. Our results showed that new cultural method was better than the conventional method except the input cost. If government provide 80% subsidy for machine cost then its input cost will be reduced by 45.4% than the conventional method.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1329-1336
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• 2011

The objectives of this study are to examine the processing of oils contamination soil by means of using a micronano-bubble soil washing system, to investigate the various factors such as washing periods, the amount of micro-nano bubbles generated depending on the quantity of acid injection and quantity of air injection, to examine the features involved in the elimination of total petroleum hydrocarbons (TPHs) contained in the soil, and thus to evaluate the possibility of practical application on the field for the economic feasibility. The oils contaminated soil used in this study was collected from the 0~15 cm surface layer of an automobile junkyard located in U City. The collected soil was air-dried for 24 hours, and then the large particles and other substances contained in the soil were eliminated and filtered through sieve No.10 (2 mm) to secure consistency in the samples. The TPH concentration of the contaminated soil was found to be 4,914~5,998 mg/kg. The micronano-bubble soil washing system consists of the reactor, the flow equalization tank, the micronano- bubble generator, the pump and the strainer, and was manufactured with stainless material for withstanding acidic phase. When the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 30 minutes were respectively identified as 4,931 mg/kg (18.9%), 4,678 mg/kg (18.9%) and, 4,513 mg/kg (17.7%). And when the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 120 minutes were respectively identified as4,256 mg/kg (22.3%), 4,621 mg/kg (19.7%) and 4,268 mg/kg (25.9%).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.4
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• pp.1-20
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• 1986

Physical, chemical and biological surveys on Nakdong River estuary were made from October, 1985 to September, 1986. 1. For all the seasons except summer, the sea surface temperature in northwest area of the line which linked from Seo Island to Jisim Island was I-2$^{\circ}$C lower than in southeast area, but in summer the sea surface temperature in northwest area was I-2$^{\circ}$C higher than in southeast area. On the contrary, bottom temperature of coastal area was 1$^{\circ}$C higher than that of oceanic area except winter. 2. Surface salinity in summer and fall has minimum value of 1. 9%0 and maximum value of 32.9%0. This large variation was caused by the runoff of the Nakdong River. Effect of less saline Nakdong River water in northwest area of the line which linked from Seo Island to Jisim Island was greater than in southeast area. A strong current rip always formed near this line. 3. The yellowish-green colored zone was observed in the Nakdong River estuary throughout the year by influence of river discharge. The characteristics of the water quality in the zone have shown that the water color was grade 7 by the Forel water-color meter, transparency was less than 4 m, and concentration of suspended solids was more than 5 mg/1. This water body was in the state of eutrophication in terms of chlorophyll-a and inorganic nitrogen concentration during summer season. 4. During the study period, total 276 taxa were identified. Most of them were diatoms and dinoflagellates which consisted of 97.5%. The component ratio of the above two groups was 84.4% and 13.1 % respectively. Diatoms were plentiful in December and dinoflagellates in July. Dominant species were Nitzschia seriata in October, Thalassiosira rotula in December, Skeletoncma costatum in April, and Nitzschia longissima in July. 5. A total of 47 zooplankton taxa was identified from the samples collected. Copepods were numerically the most important components of zooplankton communities in the study area. The domir:ant copepod species were Paracalanus parvus, Acartia clausi and Temora turbinata. Noctiluca scintillans was the next important component. The other zooplankton with minor abundance were Cladocera. Sagitta spp., Cnidaria, Mysidacea, Lucifer spp. and Amphipoda. 6. During the study period, fishes from 47 families and 87 species were sampled in th~ study area. The four most abundant fish species were Rep~mucen//'s valencicnnei, Leiognathus n~cha!is, Amblychaeturicllthys hexanema and Sardirel/a zun:zsi. The fish species of the secondary importance in abundance were Cynoglossus joyneri, Sillago sihama, Engra~lis japonicus, Encdrias nebulos'l, Acanthogobius flavimanus, Trichiurus lepturus, LiParis tanai/ai, Cynagloss//'s interruptus, Aj)ogon line:z!us, Thrissz la 1l.'1la!ensis, and Limanda yokohamac.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.85-94
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• 2005

A fungal isolate was newly collected from Zoysiagrass 'Anyang-Joongji' in small circular patches on a fairway ofa golf course in Korea, which seriously occurred during the early summer period of 2005. The isolate presented on PDAmedium, named Scz1, was closely identical to Sclerotinia homoeocarpa, a casual fungus of dollar spot disease, in cool season turf grasses such as creeping bentgrass. Hereby, this study was accomplished to characterize the isolate and compare it with the fungus, named Scb1, isolated from dollar spot-infected creeping bentgrass (Agrostis palustris Huds. cv Penncross). On PDAmedium, individual mycelial appearance of three isolates was very similar except for the pigment. Mycelial pigments of Scz1 and Scz2 (another analogous isolate collected) were light pinkish on the reverse side of PDA medium but that of Scb1 was dark brownish. In a microscopic study, three isolates were barely distinguishable in the appearance of mycelia. As expected, in the temperaturesensitivity assay, all pathogens were very delicate to $32^{circ}C$ above but not to $30^{circ}C$ below, in which was explained to be one of typical characteristics in S. homoeocarpa. In an artificial inoculation assay, disease symptoms including leaf spots in Zoysiagrass were appeared within 6-7 days after inoculation through the hand inoculation method with the isolate-infested soil. Then the fungus was re-identified from the infected leaf tissues. Interestingly, inoculation of isolate Scz1 gave rise to distinct symptoms in only Zoysiagrass but not in creeping bentgrass 'Penncross' and Kentucky bluegrass 'Midnight'. The observation might be involved in host specific pathogenecity of S. homoeocarpa Scz1 to Zoysiagrass. In a chemical sensitivity assay for the isolate, Scz1, showed a high mycelial inhibition against two fungicides, iprodione and propiconazole. All results described above suggest that S. homoeocarpa Scz1 is a primary pathogen of Zoysia dollar spot disease.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.244-250
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• 2008

The purpose of this study was to measure fundamental data required for the prediction of milling ratios, and to develop regression models to predict the head rice ratio of milled rice using NIR spectra of hulled rice. A total of 81 rice samples used in this study were collected from Jeongeup, Jeonbuk province in 2006. NIR spectra were measured using one mode of measurement, reflection. The reflectance spectra were measured in the wavelength region of 400-2500 nm with an NIR spectrophotometer "NIRSystems 6500" (Foss, Silverspring, USA). Calibration equations were developed by the modified partial least squares (MPLS), partial least squares (PLS), and principal components regression (PCR). Math treatments were 1-4-4-1, 1-10-10-1, 2-4-4-1, and 2-10-10-1. The software used was WinISI (Infrasoft International, State College, USA). Automatic head rice production and quality checking system used was "SY2000-AHRPQCS" (Ssangyong, Korea). The calibration was made with the first derivative and the spectrum designated was in 8 nm interval. The determination coefficients of head rice ratios were 0.8353, 0.8416 and 0.5277 for the MPLS, PLS and PCR, respectively. Those obtained with 20 nm interval were 0.8144, 0.8354 and 0.6908 for the MPLS, PLS and PCR, respectively. The calibration was made with second derivative that spectrum designated was 8 nm in interval. The determination coefficients of head rice ratios were 0.7994, 0.8017 and 0.4473 for the MPLS, PLS and PCR, respectively. Those with 20 nm interval were 0.8004, 0.8493 and 0.6609 for the MPLS, PLS and PCR, respectively. These results indicate that the accuracy of determination coefficient for MPLS and PLS is higher than that of PCR.