• Journal of Welding and Joining
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• v.25 no.4
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• pp.28-34
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• 2007

The heating unit of direct heating method manufactured as the plasma spray coating of $TiO_2/NiCr$ conductive heating material on the surface of heating unit in order to improve the disadvantages of indirect heating method. $TiO_2$ and NiCr (80wt.%Ni-20wt.%Cr) that had the properties of conduction and heating was chosen for the conductive heating material. The compositions of the composite powders were studied $TiO_2-30wt.%NiCr\;and\;TiO_2-10wt.%NiCr$. As the heating temperature was increased, the hardness of heating layer was increased because of the fine microstructure and the decrease of porosity. The adhesion strength was decreased for coarsening and connection of voids in the insulation layer, and the electrical resistivity of heating layer was increased for fine crack formation and growth. In this study, the best efficient sprayed coatings with heating unit was concluded as the plasma sprayed $TiO_2-10wt.%NiCr$ coatings that was heat treated at $300^{\circ}C$.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1205-1210
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• 1999

Far infrared ceramic/aluminum composite powders for thermal spray were fabricated by spray drying method and investigated the characteristics of the plasma sprayed coating layers, I.e. microstructure, phases, thermal shock resistance and spectral emissivity. The shape of the spray dried composite powder was spherical and the particle size distribution was 34~105${\mu}m $. Aluminum was distributed homogeneously in the spray dried composite powder. Spectral emissivity of the plasma sprayed coating layer ranges from 3 to 14${\mu}m $ whereas spectral emissivity of the raw ceramic powder ranges from 8 to 14${\mu}m $. And then spectral emissivity of the coatings was better than that of the raw powder but spectral emissivity was decreased with increasing aluminum content. It was found that aluminum content ranging from 20 to 30wt% was suitable for fabricating far-infrared radiator by plasma spraying method.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.165-175
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• 1996

Fourteen(14) large commercial buildings located in Seoul with friable sprayed-on surface insulation material on ceiling were investigated for fiber types in bulk material and for airborne fiber concentrations in buildings by transmission electron microscopy (TEM) in order to compare the results with those by polarized light microscopy (PLM) and phase contrast microscopy (PCM). The results were as follows: 1. Chrysotile asbestos was found in one bulk sample out of total 14 bulk samples collected. Glass fiber and mineral wool were the two major constituents of the bulk samples. 2. The Na-Mg-Si-Ca-Fe-Al ratios of the EDX spectra which were normalized with the Si peak were 0-1.0-10-8.3-4.0-4.0 in mineral wool and 0-5-10-21-0-0 in chrysotile asbestos, respectively. 3. Airborne fiber concentrations were log-normalcy distributed and the geometric mean (geometric standard deviation) fiber concentrations by TEM in the underground parking lots and inside buildings were 0.0048 f/cc(1.93) and 0.0040 f/cc(2.27), respectively with no statistical difference. In the outdoor ambient air, statistically significantly lower concentration of 0.0018 f/cc(2.04) was measured. 4. The TEM/PCM ratios of airborne fiber concentrations ranged 0.5 - 2.0 for 80 % of airborne samples analyzed, end the regression equation between TEM and PCM was PCM=-0.2724+1.1355(TEM) with the coefficient of determination $R^2=0.52$. The results of this study confirmed that the sprayed-on surface insulation material found in some commercial buildings may possibly be contaminated with asbestos fiber. Since statistically significant relationship of fiber concentrations measured by PCM and TEM inside buildings and ambient air was found, previous results by PCM in ambient air could be used to estimate the ambient fiber concentrations in knowing the ratio of TEM/PCM.

• Journal of the Korea Institute of Building Construction
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• v.20 no.6
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• pp.481-488
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• 2020

The arc thermal metal spraying method (ATMSM) has been used in Korea to improve the electromagnetic pulse (EMP) shielding effect of building and infrastructure by three machines of MS, KMS and HMS (Metal Spray, Korea Metal Spray, High-frequency Meta Spray). The adhesion ability of sprayed metal was found to be 58.32, 64.66 and 87.62% for MS, KMS and HMS, respectively. The metal sprayed area per hour of MS, KMS and HMS was calculated and found to be 14.3, 19.25 and 22.16㎡/h, respectively. The HMS showed the highest metal spray area attributed to the diameter of metal wire i.e. 1.6mm which sprayed 80 mm with 18 m/min. There was minimum loss of metal and the highest efficiency by HMS compared to others. Therefore, it is suggested to use HMS for metal spraying by ATMSM to enhance the EMP shielding effect.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1035-1045
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• 2022

The purpose of this study is to examine whether spraying an anti-microbial agent into the slurry pit will reduce the noxious odor substances from piggery barns. For this, a total of 200 crossbred ([Landrace × Yorkshire] × Duroc) growing pigs with an initial average body weight (BW) of 23.58 ± 1.47 kg were selected and housed in two different rooms, i.e. control (CON) and treatment (TRT). Each room has 100 pigs (60 gilts and 40 borrows). For a period of 42 days, all pigs were fed with corn-soybean meal-based basal diet. Later the noxious odor substances were measured by the following methods. First, fecal samples were randomly collected and stored in sealed and unsealed containers, and sprayed with the non-anti-microbial agent (NAMA) (saline water) and multi-bacterial spraying (MBS) agent (200 :1, mixing ratio-fecal sample : probiotic), Second, the slurry pit of CON and TRT rooms were directly sprayed with NAMA and MBS, respectively. The fecal sample that was stored in sealed and un-sealed containers and sprayed with MBS significantly reduced NH₃ and CO₂ concentration at the end of day 7. However, at the end of day 42, the fecal sample showed a lower H₂S, methyl mercaptans, acetic acid, and CO₂ concentration compared to the unsealed container. Moreover, at the end of days 7, 14, 21, 28, 35, and 42 compared to the CON room and TRT room slurry pit emits lower concentrations of NH₃, acetic acid, H₂S, and methyl mercaptans, and CO₂ into the atmosphere. Based on the current findings, we infer that spraying anti-microbial agents on pig dung would be one of the better approaches to suppress the odor emission from the barn in the future.

• The Korean Journal of Pesticide Science
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• v.18 no.1
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• pp.26-32
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• 2014

This study was conducted to evaluate pest control efficacy of environment-friendly agricultural materials (EFAMs) according to their spray time and frequency against alfalfa weevil, Hypera postica Gyllenhal, at Chinese milk vetch field in Miryang, Korea. Larva, pupa and adult of H. postica occurred more in year 2010 than those in 2011, and the larval population peaked 5 days faster in year 2010 than on $10^{th}$ May in 2011. Control efficacies of EFAMS sprayed on various time and in several frequencies to H. postica during April in 2010 were 73.6%, 71.9% and 66.2% at single spray in early, middle and late April, respectively and ranged from 77.1% to 78.9% when sprayed twice. With three times spray the control efficacy averaged 87.2%. Control efficacies of EFAMs with a single application in early, middle and late April in 2011 were 57.9%, 66.8% and 65.2%, respectively and ranged from 73.7% to 76.8% when sprayed twice. Control efficacy averaged with 82.7% when EFAMs were sprayed for three times. Accordingly, control efficacy of EFAMs against was increased with increasing spray frequency. Among the tested, Ungsamee(R), Wangjoongwangeco(R) and Muchungjidae(R) with a single application showed relatively higher control efficacy with a 4 to 16% lower control rate than a chemical insecticide, etofenprox 20EC. Therefore, Ungsamee(R), Wangjoongwangeco(R) and Muchungjidae(R) can be effectively used for management of H. postica when sprayed at early April for high occurring population and middle April for low occurring population with a single spray.

• FLOWER RESEARCH JOURNAL
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• v.19 no.2
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• pp.89-95
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• 2011

This study was conducted to improve commercial quality of cut spray chrysanthemums 'Charming Eye' and 'Pink Pride' bred in Korea by foliar application of daminozide, suppressing excessive elongation of peduncle caused by high temperature in greenhouse. Applications were made at two floral-bud-developmental stages and concentrations used were 0, 500, 1000, and $2000mg{\cdot}L^{-1}$. As for 'Charming Eye', cut flower length, peduncle diameter, stem diameter, flower bud diameter, and the number of flower buds did not show any significant difference among all treatments including control. However, the suppressing effect of peduncle elongation, widening angle of flower cluster arrangement on apical part, and increasing parallel flower buds in stage I showed better than those in stage II regardless of daminozide concentration. As for 'Pink Pride', cut flower length, peduncle diameter, and stem diameter did not show any significant difference among all treatments including control but angle of flower cluster on apical part increased compared to control as daminozide was sprayed at stage I and II except $2,000mg{\cdot}L^{-1}$ daminozide-sprayed at stage II. The number of flower buds and flower bud diameter showed the greatest increment through $1,000mg{\cdot}L^{-1}$ daminozide-sprayed at stage I and did the least values as sprayed with $2,000mg{\cdot}L^{-1}$ daminozide at stage II. Daminozide also gradually reduced peduncle length in a concentration-dependant manner but elongation of peduncle foliar-sprayed at stage I showed the more suppressing effect than that at stage II. Increasing the number of parallel flower buds showed the best results when sprayed with $2,000mg{\cdot}L^{-1}$ at stage I. In conclusion, we recommended that foliar spraying with $500-1,000mg{\cdot}L^{-1}$ daminozide at stage I and foliar spraying with $1,000-2,000mg{\cdot}L^{-1}$ daminozide at stage I improved cut flower quality of 'Channing Eye' and 'Pink Pride', respectively.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.412-418
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• 2009

This study is conducted in order to know the residue patterns of insecticide cypermethrin and fungicide diethofencarb in ginseng sprayed by various application methods. Two pesticides were sprayed separately on ginseng using traditional, soil and vinyl mulching applications. The vinyl mulching application was that head part of ginseng protected from pesticides. When cypermethrin was sprayed on ginseng by traditional application, its residue amount in ginseng was 0.25 mg/kg which exceeded 0.1 mg/kg, maximum residue limit(MRL) established by Korea Food & Drug Administration(KFDA). But in case of vinyl mulching and soil application, its residue amounts were 0.04 and 0.07 mg/kg, respectively. The residue amount of diethofencarb in ginseng was 3.01 mg/kg which exceeded the MRL, 0.3 mg/kg. Further, in case of vinyl mulching and soil application, its residue amounts were 1.71 and 9.39 mg/kg which exceeded the MRL 0.3 mg/kg. Although the residue amounts of both pesticides exceeded the MRLs for ginseng, we can explain that pesticides remained in head part of ginseng is probably the reason why higher pesticides residue levels were observed.

• Journal of the Korean Institute of Gas
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• v.18 no.1
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• pp.17-24
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• 2014

LNG storage tank is a facility to store liquefied natural gas (LNG) and its safety and stability to be greatly needed. When there is a LNG leakage in case of primary container problem, a special facility such as a bund wall should be constructed to store the leaked LNG. But this method makes the land usage inefficient and construction price high. So nowadays the full containment type LNG storage tank is selected instead of constructing a bund wall. In the full containment type tank, the concrete sidewall has the ability to store LNG temporarily. There are largely two methods to give the concrete sidewall the ability. In a method, rebar should be used when constructing the side wall of the LNG storage tank. In the other method, the protecting material such as sprayed polyurethane foam should be applied on the inner surface of the concrete sidewall. Sprayed PUF keeps the temperature of the sidewall above the specified temperature during the specified periods. Recently the thermal stability reinforcing method using sprayed polyurethane foam has been applied to all LNG storage tank built in Korea.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.299-304
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• 2007

Surveying, laboratory and field trial were performed to elucidate the causes of non-spinning syndrome of silkworm, Bombyx mori, abnormal symptoms of silkworm instars observed in certain sericultural fanning region. Mortality and growth of silkworm was still influenced by feeding the mulberry leaves sprayed with 10,000 fold diluted solution of standard spray of diflubenzuron WP (25%). Mortality and growth of silkworm fed with diflubenzuron-sprayed mulberry leaves with recommended spray solution were entirely affected even six weeks after spraying irrespective to the instars. Larval period of 5th instar and cocooning duration of silkworm was not affected in case 50m of buffer zone has maintained in near-by orchard field sprayed with diflubenzuron WP (25%). However, survival rate of pupae was not influenced in case 100 m of buffer zone has kept. Insect growth regulating insecticides were required to keep a certain distance of buffer zone when sprayed with water-diluted solution, 100 m from the application site at least in order to prevent contamination of the spraying drift by the chemicals.