• Computers and Concrete
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• v.33 no.6
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• pp.631-642
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• 2024

The present study concerns the corrosion mitigation of electrochemical chloride extraction (ECE) in concrete structure. Concrete specimen was fabricated with 5.0% chloride in cast, while the other specimen was exposed to 4.0M NaCl solution for 1 year to accelerate corrosion of steel. Then, the ECE was applied to the concrete specimen with 1000 mA/m² of the current density for 2, 4 and 8 weeks, respectively. During the ECE, the corrosion current density and corrosion potential were regularly monitored. As a result, the ECE was very effective in mitigating the degree of corrosion on the steel surface. The corrosion current density was significantly reduced from thousands to decades mA/m², while the corrosion potential was mostly shifted to positive direction. Assuming that the corrosion starts at 1.0 mA/m² of the corrosion current density or/and -275 mV vs SCE of the corrosion potential, the ECE could not fully achieve the repassivation of the steel, although its degree was lowered more or less depending on the duration of the treatment and type of chloride contamination. A visual examination confirmed that an increase in the duration of the treatment could lower the rust formation, but never fully removed all rust stains.

• Research in Plant Disease
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• v.21 no.4
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• pp.337-340
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• 2015

During July to November 2014, severe rust infection was consistently found on Peucedanum japonicum growing farm in Yeosu, Korea. The rust was observed mainly on lower leaf surfaces. Symptoms of typical plants included yellow-orange rust pustules were observed on the petiole and leaf surface with small yellowish to chlorotic lesions on the upper surface. No symptom was observed on flowers. Uredinia were occurred amphigenous on leaf surface, and occasionally caulicolous, scattered or loosely aggregate, rounded to oblong, 0.4 to 4 mm in diameter, covered by epidermis, then naked, surrounded by ruptured epidermis, pulverulent, and brown. Urediniospores were ovate-ellipsoid, ellipsoid or subglobose, light brown, 20 to $45{\times}15$ to $35{\mu}m$, walls 2 to $4{\mu}m$ thick. The resulting sequences were deposited in GenBank with accession No. KT778808, KT778809, and KT778810, respectively. Since this was the first accession of 28S sequence Puccinia jogashimensis, there was no exact match in GenBank nucleotide database. On the basis of the morphological characteristics and phylogenetic analyses of 28S rDNA, the fungus was identified as P. jogashimensis. To our knowledge, this is the first confirmed report on the occurrence of P. jogashimensis on P. japonicum in Korea.

• Korean Journal Plant Pathology
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• v.3 no.4
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• pp.277-284
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• 1987

Infection rate of the blister rust was investigated with special reference to the effect of eight stand factors at 221 plots selected from 131 Korean pine(Pinus koraiensis S. et Z,) stands, and the data were analyzed by multivariated statistical analysis. Environmental factors such as the density of Pedicularis spp., alternate hosts of the Korean pine blister rust, altitude, stand age, aspect, and pruning treatment, from the highest to the lowest were found to be related to the occurrence of the rust disease, Density of Pedicularis spp, was the most closely related to the' infection rate than any other factors, Especially, Pedicularis spp. growing naturally inside the pine stand had an important effect on the infection rate, but those on the outside more than 100m away had little effects, The higher the elevation, the heavier the infection rate. Infection was the heaviest at the altitudes of above 1,000m with high relative humidity and cool temperature. Infection rate was severe in young stands below 10 years old and had a reducing tendency as they mature. Stands above 16 years old were more resistant. The infection rate by the aspect of stand was higher at E- NE and W -SW exposures than at S-SE and N -NW. The infection rate at non-pruning stands was higher than at pruning stands with the lowest branch being at least 60cm high from the ground.

• Research in Plant Disease
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• v.19 no.1
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• pp.45-48
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• 2013

Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. Rusts can affect a variety of plants. Development of new effective and environmentally benign agents against rusts is of great interest. In this study, we investigated the disease control efficacy of the emulsion concentrate (EC10) and wettable powder (WP20) type formulations of the extract of Magnolia officinalis (Magjia90; containing honokiol and magnolol at 90%) against rust diseases of perilla and zoysiagrass in fields. The treatment of EC10 and WP20 of Magjia90 showed control values of 47.9% to 69.6% and Magjia90-WP20 reduced more effectively the development of rust symptoms on perilla plants than Magjia90-EC10. Magjia90-WP20 also highly suppressed zoysiagrass rust with control values of 65.7% to 80.5%. On the other hand, no harmful effect of Magjia90-EC10 and Magjia90-WP20 was observed on the perilla and zoysiagrass plants tested. The results strongly indicate that the extract of M. officinalis (Magjia90) can be used as a natural fungicide for the control of rust diseases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2391-2400
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• 2015

Weather proof steels are used for steel bridges due to its high corrosion resistance under atmospheric conditions. However, instead of forming stabilized rust layers, general rust occurs on weather proof steels under high humidity condition close to seawater or shady places. In Japan, therefore, they perform rust stabilization treatment instead of unpainted treatment due to severe atmospheric conditions. However, most of domestic weather proof steels were constructed unpainted in the form of closed box-girder, which makes the periodical repetition of dry and wet hard to occur. For the steel bridges constructed on the Han river, the evaporation of water, dew condensation due to temperature change, and stagnant water due to rain affect harmfully on the formation of passive film on weather proof steels. Thus, in this research, in order to analyze corrosion properties inside the closed box-girder for the unpainted weather proof steel bridge in the waterworks safety zone, multiple ways of analysis such as observation with eyes, cellophane-tape test, steel thickness measurement, surface corrosion potential measurement, electron microscope analysis, and X-ray diffraction analysis of the rust were performed. As a result, unstable rust layer was observed inside the closed box-girder, and severe corrosion was observed on the top and bottom of the flanges due to the effects of stagnant water caused by rain, dew condensation, and de-icing materials.

• 보존과학연구
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• s.33
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• pp.125-148
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• 2012

The Octagonal nine storied pagoda of Woljeongsa Temple consists mainly of granite with the rockforming minerals quartz, plagioclase, microcline, and biotite. The surface of the stone stupa is light brown that has been discolored by the rust from the metal ornament and aids. The surface of the stylobate and roof stone is colonized by biological contaminants. Therefore, a comprehensive deterioration diagnosis was carried out in this study, and conservation treatment was conducted. It was proven that the $Fe^{2+}$ yield increases depending on the count of poultice used with oxalic acid, but the $Mg^{2+}$, $Al^{3+}$, and $Ca^{2+}$ yields were marginal following the preliminary test. Therefore, the use of poultice is an effective way of removing the rust, and only marginally influences the rock. The biological contaminants were removed through dry cleaning, and the soil located under the contaminants was removed through wet cleaning. Based on this, the dry and wet cleaning of all the biological contaminants, and the use of poultice with oxalic acid, were done to remove the rust. For the conservation treatment of the metal ornament, the rust was removed through physical cleaning, and anticorrosion treatment was performed on the iron ornament using Renaissance wax and copper ornament by BTA.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.256-259
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• 2016

An obligate plant pathogenic fungus Puccinia zoysiae Dietel, the causal agent of rust disease, which is implicated in the damage of zoysiagrass (Zoysia spp.) in Korea. The fungus is one of the important pathogens, which attacks and colonizes susceptible zoysiagrass. Zoysia rust disease was observed in Jangseong, Hoengseong and Hapcheon in 2014 and 2015, Korea. The typical symptoms of the disease appeared first as small white spots on the leaf and stem of zoysiagrass plants, and turn brownish, dark brown spores revealed on the lesions. Uredospores were light brown in color, ellipsoid or spherical in shape and $22.0{\sim}25.0{\times}15.0{\sim}17.5{\mu}m$ in size. On the basis of the morphological characteristics, the fungus was identified as P. zoysiae. Pathogenicity of the fungus was proved by artificial inoculation on Z. japonica. The rust disease firstly appeared approx. early or middle June and then increased middle of October in Korea. In field, Z. matrella ecotypes were more resistant than Z. japonica ecotypes against the pathogen. Disease response against the pathogen was different among ecotypes of each species, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.465-476
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• 2021

Scale and rust generation in water pipes is a common phenomenon when cast iron water pipes have been used for a long time. A physical water treatment device is known among various means for suppressing rust in a water pipe, and a zinc ionization device for putting zinc metal into a pipe and emitting the zinc cation into water is one of such devices. This research measured the amount of zinc ion generated, which is known to exhibit an effect of inhibiting rust and scale generation in a pipe, and examined the scale and rust inhibition effect of the ionization device installed for ground or building water supply. In the case of distilled water, the concentration of zinc ion increased by circulating water in the ionization device several times, and it was verified to be hundreds of ㎍/L, and in the case of discharging ground or tap water, it was verified to be tens of ㎍/L. In addition, a verification pipe was installed to confirm the change inside the pipe before and after installation of the zinc ionization device, and the internal condition of the pipe was observed 3 months to several years after installation. It was confirmed that the corrosion area of the surface of the pipe was no longer increased by installing a corrosion inhibitor, and if the pipe was already filled with corrosion products, the amount of corrosion products gradually decreased every year after installation. The phenomenon of fewer corrosion products could be interpreted as expanding the space in the pipe due to the corrosion product as Fe₂O₃ adhered to the inner surface of the pipe and turned into a smaller black Fe₃O₄. In addition, we found that scale such as CaCO₃ together in the corrosion by-products gradually decreased with the attachment of the ionization device.

• The monthly packaging world
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• s.121
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• pp.138-141
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• 2003

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.49-51
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• 1983