• The Korean Journal of Pesticide Science
• /
• v.12 no.4
• /
• pp.351-356
• /
• 2008

This study was carried out to assess adoptability and environment impacts of ultra low volume (ULV) pesticide spray solutions aerially sprayed by manned-helicopter. Uniformity of the deposited amount in paddy fields was uneven, showing $3.1{\sim}4.7$ times differences among surveyed sites. Drifting distance of aerially sprayed droplets from the target area was within 30 m in the wind direction and 20 m in the opposite direction. Most of the aerially sprayed pesticides were deposited in/on rice plants, while those in submerged paddy water and soil were relatively small. The degradation rate of the deposited pesticides was in the decreasing order of rice plants, paddy water and soil. Soil residues of pesticides in the aerially sprayed rice paddy fields after harvest ranged from non-detected to 0.201 mg/kg. However, no pesticides were detected in brown rice and rice straw. No phytotoxic symtoms were observed in rice plants and nearby non-target crops by the sprayed pesticides.

• Journal of the Korean institute of surface engineering
• /
• v.42 no.5
• /
• pp.208-215
• /
• 2009

We employed atmospheric plasma to reactively remove the lubricant sprayed onto such industrial electronic parts as LCD chassis during sheet-metal forming processes and investigated basically the effect of plasma parameters on cleansing the surfaces of zinc-electroplated steel plates (EGI). Specimen prepared with some controlled amount of lubricant sprayed on their surfaces beforehand were subjected to two different kinds of atmospheric plasma, one being generated by using air and the other generated by using nitrogen (99.9% purity). Locating the plasma beams at the height range between 3.5 and 13.5 mm from the surface of each specimen and radiating for 5 to 30 seconds resulted out that the cases with a position of 3.5 mm and a duration of 5 seconds or longer showed the surfaces completely cleansed without a trace of lubricant. Furthermore we found out that the plasma generated by using simple air depicted higher cleansing ability than the other one generated by using expensive nitrogen, interestingly useful very much for industrial purposes. On another aspect, we confirmed that the drilled or cut surfaces of Zn-plated steel substrate would not be oxidized even under the influence of plasma during its cleansing process. Therefore, we could probably conclude from this fore-survey that a dry process adopting atmospheric plasma for cleansing industrial parts might be determined to become successful in terms of commercialization, cautiously.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.2 no.1
• /
• pp.75-78
• /
• 2001

The whitefly, Dialeuropora decempuncta Quaintance and Baker (Homoptera : Aleyrodidae) causing considerable damage to mulberry, Morus alba. Crop loss caused by the whitefly was estimated in mulberry. Quantitative yield loss was estimated on the basis of harvest data from both sprayed and unsprayed plots. Data on pest incidence has been recorded at weekly intervals in both sprayed and unsprayed plots from 30 th day of plant age till harvesting i.e., 60 days after pruning in August October season. An attempt has been made to establish a relationship between whitefly population and percentage of crop loss due to it. Percentage of crop loss due to whitefly has got a linear relationship with the whitefly population. An initial population of 24 adults/top leaf would be able to cause 24% loss (l,630 Kg leaf/ha ) in a period of 30 days. Economic analysis postulates that application of pesticide can stove a net amount of 1,630 Kg leaf/ha which is sufficient to produce 67.65 Kg of additional multivoltine cocoons. This determines the cost/benefit ratio which will enable to workout the economics of management practices.

• Journal of Sericultural and Entomological Science
• /
• v.38 no.2
• /
• pp.108-112
• /
• 1996

This experiment was carried out to investigate the feeding effect of rutin (quercetin-3-o-${\beta}$-rutinoside) and ${\gamma}$-aminobutyric acid(GAB) sprayed on mulberry leaves on silkworm growth. Amount of ingest, digest and feces showed no difference statistically except rutin. Rutin made 6% increase of amount of digest, compared to the control. However, rutin or GABA decreased maximaly silkworm weight by 28% during the experimental period. GABA showed body weight loss by 15%, rutin by 7% respectively, compared to the control. Rutin and GABA extended three days larval period and extended one day mounting period and decreased 15.4% and 91% in number of mounted silkworm compared with the control, respectively.

• Journal of the Korea Institute of Building Construction
• /
• v.13 no.6
• /
• pp.594-601
• /
• 2013

One of the important problems associated with building demolition is the dust generated during the work. The only way to reduce the demolition dust is to use a dust net during water spraying. However, it is difficult to supply the necessary amount of water to remove demolition dust, thus making it difficult to apply this method on a demolition site. This work attempted to find an alternative approach to dust removal by incorporating surfactant and high range AE water reducer in the water being sprayed. Through the experiment, it was found that the addition of surfactant did not contribute to the removal of demolition dust. However, the use of high range AE water reducer showed better performance than spraying plain water, indicating that some amount of demolition dust had been adsorbed on the high range AE water reducer.

• Journal of the Korean institute of surface engineering
• /
• v.27 no.1
• /
• pp.12-18
• /
• 1994

The plasma spray process was used to deposit coatings of $ZrO_2$-8wt%Y2O3 powders on mild steel sub-strate, and the characteristics of as-deposited and heat treated coatings have been investigated. Particulary, the variations of porosity, wear resistance, thermal barrier and thermal shock resistance in $ZrO_2$-8wt% $Y_2O_3$coatings after heat treatment under vacuum circumstance have been investigated. The porosity of the coating layer was increased with increased spray distance. In the case of the arc current of 450A and at the spray distance of 50mm, it was obtained the lowest amount of porosity. After heat treatment, the amount of porosity was found to be decreased, and the wear resistance, microhardness and thermal shock resistance were im-proved. However, the thermal barrier was decreased.

• Journal of Animal Environmental Science
• /
• v.15 no.2
• /
• pp.99-106
• /
• 2009

We conducted a comparison experiment of our wide-area spraying high speed fan with a fan which was developed by Japan MARUYAMA Inc. have been much recognized for it's history and skills in a field of spraying machine. In result, MARUYAMA Inc. fan sprayed up to 120 m and, on the other hand, wide-area spraying high speed fan of our own making was able to spray up to more than 160 m. Wide-area spraying machine have been supplied to domestic demands by importing from Japan, but it is determined to be possible that home products will occupy market for it's ability, price and A/S environment in future. The main research results are below. Some plastic cups which are in the open market are used for our experiment. After distributing 90 cups in a range of 10m vertically with localizing 5 cups horizontally and 18 cups vertically, spraying machine was moved and finally we make distribution charts by estimating the sprayed amounts on each cup. Vertical distance was set up to 5m and we calculated average values by using sprayed amount and data of 4 observers. In result our fan showed much sprayed amounts than MARUYAMA Inc. all over the field except situations of vehicle departing and stopping.

• Clean Technology
• /
• v.25 no.1
• /
• pp.19-32
• /
• 2019

As regional air pollution gets worse by the sulfur oxides emitted from various types of vessels passing through the many countries, the International Maritime Organization establishes the emission control areas and regulates sulfur dioxide in those areas. In order to satisfy these regional regulations, the fuel selection method and the exhaust gas post-treatment device are applied to the ships. Due to the economic reasons, the post-treatment method of exhaust gas for reducing the amount of sulfur oxides discharged is mainly preferred. The scrubber which is dominantly used in the ships are the spray type system where the sprayed liquid drops used for capturing the soluble sulfur dioxides in the exhaust gas. The performance of the spray type system depends on the size distribution of the sprayed droplets. In order to evaluate this performance, we designed counterflow type scrubber and cyclone scrubber and evaluated the desulfurization efficiency and the amount of droplet evaporation according to the size of each droplet by using computational fluid dynamics. The Eulerian-Eulerian analysis method was used because the scrubber had a gas-liquid two-phase flow inside the scrubber. When the diameter of the droplet was $100{\mu}m$, $300{\mu}m$, $500{\mu}m$ and $700{\mu}m$. As a result, both of scrubbers showed high desulfurization efficiency and low evaporation amount at $500{\mu}m$ and $700{\mu}m$.

• Korean Journal of Environmental Agriculture
• /
• v.5 no.2
• /
• pp.119-129
• /
• 1986

Disappearence of the trichlorfon (Dipterex) in the forest, following aerial to control Agelastica coerulea B., were studied by sampling deposits on slide glasses, soils, water, and leaves, and analysing with a gas chromatograph equipped with an electron capture detector. By analysing the amount remained on slide glasses, it was shown that the pesticide was adequately sprayed and nearly all deposit was lost in a day. The amount deposited under the tree was about 1/100 of the amount at an exposed site. Concentration of trichlorfon in creek water was 10 to 100 times as high as the acute toxic level to zooplankton for 6 to 24 hours, The rain could recontaminate the stream water up to the toxic level. Loss rate of trichlorfon from soils showed variations by sampling sites and was generally slower than from slide glasses. Amount deposited on leaves were less than the calculated or expected amount. The loss from leaves were similar to that from soil.

• Journal of ILASS-Korea
• /
• v.28 no.1
• /
• pp.43-48
• /
• 2023

The waste-heat-recovery boiler with water spray (HR-B/WS) applies the heat exchange between the inlet air and exhaust gas with the water spray into the inlet air. The evaporation of water in the inlet air promotes heat recovery from the exhaust gas so that thermal efficiency can be improved by the enhanced condensing effect. The NOx emission can also be reduced by lowering the flame temperature due to the dilution effect of the water. In this study, the validity of this concept is examined by the practical boiler test performed with a 24 kW condensing boiler under the full load condition according to the water injection amount. The theoretical amount of water injection is calculated under the assumption of full evaporation of the sprayed water, which is calculated as 50 g/min. Since the injected water cannot evaporate fully in the actual system, the maximum water spray amount is set as 100 g/min. The results showed that the water injection can increase the thermal efficiency up to 95.59% and reduce NOx and CO emissions simultaneously to 8.9 ppm and 35 ppm at 0% of O₂. Although the heat energy loss increased due to the unevaporated water, the increase in water injection amount caused higher thermal efficiency due to the increased amount of the evaporated water.