• Ecology and Resilient Infrastructure
• /
• v.7 no.1
• /
• pp.63-71
• /
• 2020

Various types of amendments have been studied for heavy metal stabilization in soil. However, researches on the effect of amendments on alkali soil and their effects on the plants at various edible parts are insufficient. The aim of this study was to evaluate the stabilization efficiency of heavy metals and their transfer into edible parts of food crops. Abandoned mine area was selected and 3 types of amendments (lime stone, LS; steel slag, SS; acid mine drainage sludge, AMDS) was applied with 3% (w/w). in field. After 6 month aging, Chinese cabbage (leafy), bok choy (leafy), garlic (root) and red pepper (fruit) were transplanted and cultivated. For chemical assessment, total concentration and bioavailability using Mehlich-3 solution were determined. For biological assessment, fresh weight and heavy metal uptakes were analyzed. It was revealed that AMDS reduced bioavailability most effectively, resulting in the decrease in heavy metal concentration in edible parts of all crops. When explaining the heavy metal uptake of plants, the bioavailability was more appropriate than the total contents of soil heavy metals. Therefore, bioavailability-based further research and management practices should be carried out continuously for the sustainable environment management, safe crop production, and human health risk reduction.

• Research in Plant Disease
• /
• v.12 no.3
• /
• pp.240-248
• /
• 2006

Control of white rot which is one of the most serious apple diseases in Korea has mainly relied on periodical spray of protective fungicides. As the main inoculum source of the disease is pycnidiospores produced in the warts formed on affected stems of apple tree, it can be conceivable that inhibition of spore production might be an effective means for controlling the disease. Inhibitory efficacy of eight selected fungicides against sporulation of the fungus was assessed by counting the number of spores produced at detached warts treated with the fungicides of recommended dilution. They showed diverse effect on sporulation. Carbendazim and azoxystrobin suppressed sporulation almost completely, the former irreversively. Thiram and folpet promoted sporulation as producing much more number of spores than untreated control. Others showed almost no effect on sporulation. Effects of suppression and promotion in the sporulation shown by the fungicides on the control of white rot were examined by incidences of disease and infection at the plots adopted the spray programs of which the fungicide at late May was substituted by carbendazim, azoxystrobin, folpet and thiram, respectively. Disease incidence and infection frequency at the plots sprayed former two chemicals which suppressed sporulation were much lower than those of the plots adopted latter two chemicals and untreated plot at which the fungicide spray was skipped at that time. These facts were reconfirmed in the experiments conducted with carbendazim and thiram, in which 100 fruits were bagged just prior to each spray from late May to late July for elucidating the effect of the two fungicides on the action of subsequent ones. Disease incidence and infection frequency on the fruit bagged just prior to each spray were gradually increased as the seasons going on. The increase rate at the carbendazim plot was much lower than that of thiram. Especially, the fruit infected till late July at the carbendazim plot were almost completely cured by the three fungicides, iminoctadine-triacetate, tebuconazole and samzinwang, a combined formular of iminoctadine-triacetate and difenoconazole, sprayed at late July and hence. In thiram plot, infected fruit were also cured by the 3 fungicides but not remarkable. From these results, it can be concluded that control efficiency of white rot can be greatly enhanced by selecting the fungicide capable of suppress the sporulation of white rot fungus at the season when the mass dispersal of spores is not initiated.

• Korean Journal of Organic Agriculture
• /
• v.13 no.1
• /
• pp.85-99
• /
• 2005

This trial was carried out to determine effects of organic feeds in comparison to conventional diet on feed intake, digestibility, and nitrogen retention in Korean native goats. Twelve Korean native goats were allotted to treatments in four groups of three goats and then they were housed in separate metabolism cages for 21 days. Treatments included conventional diet (A) as a control group and three organic feed groups (B: organic rice straw, C: organic nee leaves, D: organic mixture of rice straw and tree leaves). The A treatment, conventional diet, consisted of common rice straw and commercial concentrates at a proportion of 60 and 40%, respectively. All ingredients of organic feeds treatments were organically produced-agricultural products without any application of chemical fertilizer and pesticide. Four experimental diets were formulated to have the same ratio of forage to concentrate and similar contents for protein and carbohydrate across treatments and they were offered to goats ad libitum. Feed intake, apparent nutrient digestibility and nitrogen retention were investigated. For chemical compositions of experimental diets, all nutrients except crude ash and ether extract were not significantly different across treatments as we expected. Crude ash content was highest in the A treatment (P<0.05), however, it was not significantly different among organic feeds treatments. Ether extract content was higher (P<0.05) in C and D treatments than in A and B. Even if dry matter intakes for organic feeds treatments were not significantly different among them, they were significantly higher (P<0.05) compared with conventional diet. Fecal excreta were not significantly different across treatments, resulting in significantly higher digestible dry matter (g/day) in treatments of organic feeds (P<0.01). Average daily gain (ADG) and feed efficiency (FE) were more increased (P<0.01) in treatments of organic feeds compared with conventional diet. Digestibilities for most of nutrients except NFC had the same trend as ADG and FE, however, NFC digestibilities for C and D treatments were significantly lower (P<0.01) than those of A and B. Nitrogen intakes for organic feeds treatments were significantly higher (P<0.001) than conventional diet, with no difference among organic feeds treatments. Fecal nitrogen loss was higher (P<0.05) for C and D treatments than for A and B. Retained nitrogen contents were significantly higher (P<0.05) for organic feeds treatments than for conventional diet, but nitrogen retention rate did not show any difference across treatments. The results showed that organic feed supplementation more improved feed intake, digestibility and nitrogen retention in comparison with conventional diet, and thus they could be concluded that organic feeds might contribute to animal performance and a safer production of animal product.

• Proceedings of the KWS Conference
• /
• 2010.05a
• /
• pp.51-51
• /
• 2010

Recently just as in the automobile industry, shipbuilders also try to reduce material consumption and weight in order to keep operating costs as low as possible and improve the speed of production. Naturally industry is ever searching for welding techniques offering higher power, higher productivity and a better quality. Therefore it is important to have a details research based on the various welding process applied to steel and other materials, and to have the ability both to counsel interested companies and to evaluate the feasibility of implementation of this process. Submerged-arc welding (SAW) process is usually used about 20% of shipbuilding. Similar to gas metal arc welding(GMAW), SAW involves formation of an arc between a continuously-fed bare wire electrode and the work-piece. The process uses a flux to generate protective gases and slag, and to add alloying elements to the weld pool and a shielding gas is not required. Prior to welding, a thin layer of flux powder is placed on the work-piece surface. The arc moves along the joint line and as it does so, excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared with 25% for manual metal arc). SAW process offers many advantages compared to conventional CO2 welding process. The main advantages of SAW are higher welding speed, facility of workers, less deformation and better than bead shape & strength of welded joint because there is no visible arc light, welding is spatter-free, fully-mechanized or automatic process, high travel speed, and depth of penetration and chemical composition of the deposited weld metal. However it is difficult to application of thin plate according to high heat input. So this paper has been focused on application of the field according to SAW process for thin plate in ship-structures. For this purpose, It has been decided to optimized welding condition by experiments, relationship between welding parameters and bead shapes, mechanical test such as tensile and bending. Also finite element(FE) based numerical comparison of thermal history and welding residual stress in A-grade 3.2 thickness steel of SAW been made in this study. From the result of this study, It makes substantial saving of time and manufacturing cost and raises the quality of product.

• Journal of Korean Society of Water and Wastewater
• /
• v.13 no.2
• /
• pp.55-65
• /
• 1999

AF(anaerobic filter)/BAF(biological aerated filter) system and UASB(upflow anaerobic sludge blanket)/BAF system, of which system effluents were recirculated to the anaerobic reactors in each system, were operated in order to investigate the performance in simultaneous removal of organics and nitrogen in high-strength dairy wastewater. Advanced anaerobic treatment processes of AF and UASB were evaluated on applicability as pre-denitrification reactors, and BAF was also evaluated on the performance in oxidizing the remaining organics and ammonia nitrogen. At system HRTs of 4.0 to 4.5 days and recirculation ratios of one to three, the AF/BAF system could achieve more than 99% of organics removals and 64 to 78% of total nitrogen removals depending upon the recirculation ratio. Although the UASB/BAF system also showed more than 99% of organics removals, total nitrogen removals in the UASB/BAF system were 53 to 66% which are lower than those in the AF/BAF system at the corresponding recirculation ratios. Optimum recirculation ratios considering simultaneous removal of organics and nitrogen and cost-effectiveness, were in the range of two to three. The upflow AF packed with crossflow module media, as a primary treatment of the anaerobic reactor/BAF system, showed better performances in denitrification, SS removals, and gas production than the UASB. Higher loading rate of suspended solids from the UASB increased the backwashing times in the following BAF. Especially, at a recirculation ratio of three in the UASB/BAF system, the increase in head loss due to clogging in the BAF caused frequent backwashing, at least once d day. The BAF showed the high nitrification efficiency of average 99.2% and organics removals more than 90% at organics loading rate less than $1.4KgCOD/m^3/d$ and $COD/NH_3-N$ ratio less than 6.4. It was proved that the simplified anaerobic reactor/BAF system could maximize the organics removal and achieve high nitrogen removal efficiencies through recirculation of system effluents to the anaerobic reactor. The AF/BAF system can, especially, be a cost effective and competitive alternative for the simultaneous removal of organics ana nitrogen from wastewaters.

• Journal of Food Hygiene and Safety
• /
• v.17 no.1
• /
• pp.8-14
• /
• 2002

Cotinine, one of nicotine metabolites, has been blown to reduce 4-(methylnitro samino)-1-(3-pyridyl)-1-butanone(NNK)- induced $O^{6}$MeG DNA adducts significantly in A/J mice when administered together with NNK. In order to examine the effects of phyto-extract mixture on the conversion of cotinine from nicotine, cellular and clinical experiments were carried out. When the phyto-extract mixture was added to culture media, human liver cells (FLCFR5) produced cotinine from nicotine 2~3 times compared to the control. The phyto-extract mixture which was microinjected into Xenopus oocyte along with nicotine showed the almost similar production of cotinine compared with the results of hepatic cell culture. In clinical test employing 17 to 20 healthy men, concentrations of urinary cotinine derived from smoking after taking photo-extract mixture increased up to 2 times compared to the control group. These results indicatethat the phyto-extract mixture can increase the metabolic efficiency of nicotine to cotinine, leading to the reduced formation of $O^{6}$MeG DNA adducts.

• Journal of Science and Technology Studies
• /
• v.18 no.2
• /
• pp.269-306
• /
• 2018

Through this study, it is aimed to derive the policy direction considering the characteristics of the present Smart Factory, the industrial condition of Pohang area, and the promotion field. Secondly, the questionnaire data of the regional enterprises will prepare for the improvement of the industrial structure and the implications for efficiency, and preparation for regional preparation and industrial changes in preparation for the next generation of production revolution. The construction of Smart Factory in Pohang can be divided into two major directions. First, it is analyzed that smart factory pilot projects are highly needed, focusing on competitive medical precision manufacturing field among the SMEs in the region, primary metal and nonmetal manufacturing industries, and other machinery fields. In addition, local SMEs are willing to introduce smart factories for reasons of quality improvement and cost reduction, and it is confirmed that they will actively promote employee training and expertise if they can upgrade continuously.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.10
• /
• pp.712-720
• /
• 2001

Algorithms from the research of the layout migration were proposed in the paper. These are automatic recognition algorithm for the VLSI devices from it, graph based construction algorithm to maintain the constraints, dependencies, and design rule between the devices, and high speed compaction algorithm to reduce size of the VLSI area and reuse the design with compacted size for the new technology. Also, this paper describes that why proposed algorithms are essential for the era of the SoC (System on a Chip), design reuse, and IP DB, which are the big concerns in these days. In addition to introduce our algorithms, the benchmark showed that our performance is superior by 27 times faster than that of the commercial one, and has better efficiency by 3 times in disk usage.

• Transactions of the Korean hydrogen and new energy society
• /
• v.9 no.2
• /
• pp.77-84
• /
• 1998

Hydrogen isotope exchange in mixtures of $H_2O/D_2$, $H_2O/D_2O$, or $D_2O/H_2$ can be facilitated under electrical discharge. For example, a simple DC corona discharge through the mixture creates a plasma in which the reactants are excited energetically. The reactants in such plasma, due to increase in population of excited quantum levels or due to production of radicals or ions, undergo very rapid chemical reactions even at ambient temperature. The isotope exchange reaction of hydrogen(H) and deuterium(D) produces the third kind of heavy water(HDO) and isotopic hydrogen gas(HD), as shown in $D_2+H_2O{\rightarrow}HD$ K=11.257(at $25^{\circ}C$) The reaction products can be detected with temporal resolution using the Fourier transform infrared(FTIR) absorption spectroscopy. Since $H_2O$, $D_2O$ and HDO are all infrared active with different absorption peaks, FTIR proves to be a useful tool for monitoring the reaction. Experimental results show that the electrical method is indeed a useful means to promote the reaction, showing a better efficiency than traditional catalytic methods.

• Journal of Korean Society of Forest Science
• /
• v.98 no.6
• /
• pp.696-702
• /
• 2009

Yellow poplar (Liriodendron tulipifera L.) is an insect-pollinated tree species with large, perfect flower, and its seed sets average only about 10 percent naturally. In its controlled pollination, pollination bags are usually taken to prevent unwanted pollination, but bagging is an expensive and time-consuming process. Therefore, this study was conducted to determine the need of pollination bag by estimating how much unintended pollination would occur when different cross methods were applied. Five different pollination methods were applied as follows: 1) natural open pollination (i.e. insect pollination) as a reference, 2) self-pollination; no removing reproductive organs with bagging, 3) open pollination; emasculated(removing sepal, petal and stamen) without bagging, 4) controlled pollination; emasculated with bagging and 5) controlled pollination; emasculated without bagging. Very low value of full seed rate (0.2%) was observed in method 3, it was suggested that removing stamen and petal restrict the activity of pollen vectors like bee. Difference in the full seed rate between method 4 and method 5 was not significant (27.9% versus 24.0%, respectively). Consequently, controlled pollination without bagging might be an alternative method for extensive breeding and mass production of seeds in yellow poplar.