In this study, we examined the effect of orifice diameter on atomization performance such as SMD(Sauter Mean Diameter), MMD(Mass median diameter), particle size distribution, spray distance, and spray angle when water was sprayed through a siphon nozzle. In addition, the behavior characteristics of spray were analyzed using the CFD(Computational Fluid Dynamics) commercial program. In the downstream direction of the flow, the dispersion and diffusion power of the droplets increased, greatly improving atomization performance. The spray spread in the radial direction when the jet velocity of water increased. As a result, atomization performance improved as the jet velocity increased.

PURPOSES : The increasing heat wave warnings during the summer season in Korea have significant impacts on daily life and industry as a whole, especially in urban areas (such as areas with asphalt and sidewalk pavements). Heat waves directly affect urban heat island and heat dome phenomena. Various urban temperature reduction measures are being discussed to reduce urban heat islands and heat dome phenomena and to improve citizen safety against summer heat waves; suggestions include thermal packaging, rooftop greening, and expansion of vegetation areas. There is a lack of analysis on the methodology for increasing the road spraying effect during summer heat waves (e.g., there is no systematic engineering study on the effect from reducing the temperature of the road spraying during a heat wave in the city) and on the types of road pavements in the city. In addition, as the asphalt pavements of roadways and block pavements installed in sidewalks account for a considerable portion of all pavements, this study provides a more systematic and scientific approach and procedures for reducing temperatures through road spraying in the city by tracking the effects of heat waves. METHODS : In this preliminary experiment, four types of road pavement materials were selected as test specimens: asphalt test specimens (AP- 300 mm × 300 mm × 50 mm), concrete test specimens (CP-300 mm × 300 mm × 50 mm), impermeable blocks (IB-200 mm × 200 mm × 60 mm), and self-permeable blocks (PB-200 mm × 200 mm × 60 mm). As a test method to evaluate the size and duration of each spray effect package type, the surface temperature of each specimen was measured using thermal imaging cameras every 20 min after spraying at the maximum temperature point of each specimen, and the average surface temperature was analyzed based on the collected temperature data. In addition, to conduct a quantitative analysis of the effect of reducing the surface temperature of road pavements by road spraying in summer, field tests were conducted on asphalt roads and watertight blocks for sidewalks. RESULTS : As a result of the comparative analysis of the spray effect under a 36 ℃ air temperature based on a heat wave warning, the surface temperatures were, from high to low, the asphalt (68.8 ℃), concrete (59.1 ℃), impermeable block (57.3 ℃), and permeable block (58.7 ℃). The asphalt pavement had the greatest effect on the heat island and heat dome phenomena. From measuring the temperature reduction effect and sustainability of each type of road pavement, the surface temperature reduction effects were ranked in the following order: water-permeable block (Δ18.0 ℃), asphalt test piece (Δ17.5 ℃), concrete test piece (Δ12.2 ℃), and water-permeable block (over 240 min). In the report pitching block, the average road surface temperature reduction between the pore recovery and treatment was expected to continue to decrease by approximately -4.3 ℃ on the day of work and approximately -2.4 ℃ on the next day. The expected effect of the temperature reduction owing to simple spraying on the surface of the pore block was evaluated to be limited to the day. CONCLUSIONS : In the road spray effect analysis conducted on the common asphalt road, there was a slight difference in the initial temperature reduction size as the test specimen was measured, but the surface temperature difference between the non-spray section and spray section tended to be approximately Δ3°C after 140 minutes of spraying. Therefore, it was determined that the asphalt pavement temperature reduction plan through road spraying in urban areas in summer would be the most effective if it was repeated twice or more in an hour (between 13:00 and 14:00) on the day of the heat wave.

In this study, using the plasma spray method, tensile and compression fatigue tests are performed in saline solution to examine the effect of Ti undercoat on corrosion fatigue behavior of alumina-coated specimens. The alumina-coated material using Ti in the undercoat shows better corrosion fatigue strength than the base material in the entire stress amplitude range. Fatigue cracking of UT specimens occurs in the recess formed by grit-blasting treatment and progresses toward the base metal. Subsequently, the undercoat is destroyed at a stage where the deformation of the undercoat cannot follow the crack opening displacement. The residual stress of the UT specimen has a tensile residual stress up to about 100 μm below the surface of the base material; however, when the depth exceeds 100 μm, the residual stress becomes a compressive residual stress. In addition, the inside of the spray coating film is compressive residual stress, which contributes to improving the fatigue strength characteristics. A hardened layer due to grit-blasting treatment is formed near the surface of the UT specimen, contributing to the improvement of the fatigue strength characteristics. Since the natural potential of Ti spray coating film is slightly higher than that of the base material, it exhibits excellent corrosion resistance; however, when physiological saline intrudes, a galvanic battery is formed and the base material corrodes preferentially.

경기도농업기술원에서는 2016년도에 고온기 생육 및 개화 특성이 우수한 절화용 스프레이 국화 ‘Perky Star’ 품종을 개발 하였다. 2012년도에 화색이 진한 노란색이면서 좁고 긴 설상화를 가진 ‘Sei-vista’ 품종을 모본(♀)으로, 화형이 좋은 ‘Amisa’ 품종을 부본(♂)으로 인공교배를 하였고 2014년부터 2016년까지 억제재배, 촉성재배, 가을재배 작형에서 생육 및 개화특 성을 검정하였다. 2016년 기호도 조사를 통해 최종적으로 GCS12-81-150계통을 선발하여 ‘Perky Star’로 명명하였고 2017 년에 국립종자원에 품종보호출원(제2017-64호)한 후 2018년에 품종보호권이 등록(제7465호)되었다. ‘Perky Star’ 품종은 노란 색 홑꽃형으로 고온에서 화색발현과 생육이 좋았으며 꽃잎이 두꺼워 여름철 수출품종으로 적합하다고 판단되었다. 가을재 배작형, 억제작형, 촉성작형에서 단일처리 후 개화소요일 수는 각각 49, 49, 53일, 절화장은 88.3, 84.2, 103.3cm, 꽃의 직경은 5.1, 4.8, 4.8cm, 줄기당 착화수는 25.0, 21.5, 38.8개로 고온에서 절화장과 착화수가 증가하는 경향을 보였다. 흰녹병 에 완전한 저항성을 갖지는 못한 품종이며, 자연개화 작형에서 절화수명은 21.3일로 대조품종 20.2일에 비해 조금 길었고, 5점 척도로 기호도를 조사한 결과 4.2점으로 대조품종 4.1과 비슷한 선호도를 보였다.

선창은 선박의 화물을 싣는 공간으로 구조적 문제로 인해 세정작업은 위험성이 크고 작업 난이도가 높은 작업이다. 이 연구에서는 전용 선창세정기의 설계 자료로 활용하기 위해 압력변화에 따른 분무특성을 고찰한 결과 노즐 형상의 최적화를 위한 변수 요소를 확인 하였다

Butanol has an ability to improve the ignition quality due to its lower latent heat of vaporization; it has an advantage to reduce a volume of a fuel tank because its energy density is higher than that of ethanol. Also, butanol-diesel oil blending quality is good because butanol has an effect to prevent the phase-separation between two fuels. Even if the blended oil contains water, it can reduce the corrosion of the fuel line. Thus, it is possible to use butanol-diesel oil blended fuel in diesel engine without modification, and it may reduce the environment pollution due to NOx and particulate and the consumption of diesel oil. Therefore, some studies are being advanced whether butanol is adequate as an alternative fuel for diesel engines, and the results of the combustion and exhaust gas emission characteristics are being presented. Though the injection and spray characteristics of butanol are more important in diesel combustion, the has not yet dealt with the matter. In this study, the influence in which differences of physical properties between butanol and diesel oil may affect the injection and spray characteristics such as injection rate, penetration, spray cone angle, spray velocity and process of spray development were examined by using CRDI system, injection rate measuring device and spray visualization system. The results exhibited that the injection and macroscopic spray characteristics of two fuels were nearly the same.

절화용으로 재배중인 스프레이 국화 10 품종을 재료로 사용하여 각 착생 부위별 소화경의 길이와 줄기와 화서 내 엽면적 등의 형태적 특성, 절화 시 수분 흡수 및 절 화수명 등과 관련된 생리적 특성을 조사하였으며 이를 기 초로 품종 별 형질들의 변이 계수, 유전력 및 유전자 전 이율 등의 유전 분석을 통하여 금후 국화의 육종 계획 수립에 활용코자 수행한 결과를 요약하면 다음과 같다. 착생 부위별 줄기와 화서내 엽면적은 거의 모든 품종에 서 하부로부터 상부로 올라갈수록 엽면적이 증가하는 경 향이었으며 품종 간 통계학적 유의차는 인정되었다. 변 이계수와 표현형 변이계수, 유전 변이계수는 줄기 내 엽 면적에 비해 화서 내 엽면적이 상당히 높은 편이었고 오 차 또는 환경 변이계수 또한 같은 경향이었다. 유전력은 착생부위에 관계없이 현저히 높았다. 유전자 전이는 비교적 낮은 편이었으며 유전자 전이율은 줄기에 비해 화 서 내 엽면적이 현저히 높은 편으로 모든 착생 부위의 엽면적에서 100% 이상이었다. 소화경의 길이의 경우 모든 품종에서 상부로부터 하부 화서로 내려감에 따라 길어지 는 경향이었다. 각 부위별 화서의 길이의 평균치는 품종 간 차이를 나타냈으며 통계학적 유의성이 있었다. 변이계수, 표 현형 변이계수, 유전 변이계수는 비교적 높은 편이었고 오 차 또는 환경 변이계수는 낮은 편이었다. 유전력은 높은 반면 유전자 전이와 유전자 전이율은 낮은 편이었다. 꽃 목의 직경은 대부분의 품종에서 1번째 소화경의 꽃목의 직경이 가장 굵었고 아래쪽으로 내려 갈수록 가늘어지는 경향이었으며 품종 간 꽃목 직경은 거의 2배 정도로 차 이가 있었으며 통계학적 유의차가 인정되었나, 착생 부 위별 직경의 차이는 거의 없었다. 변이계수, 표현형 변 이계수, 유전 변이계수는 다소 높은 편이었으나 오차 또 는 환경 변이계수는 낮은 편이었다. 유전력은 대단히 높 았고 유전자 전이와 유전자 전이율은 대단히 낮은 편이 었다. 꽃목의 경도는 착생부위별로 일정한 경향치를 나 타내지 않았고 꽃목 경도의 평균치는 품종 간 통계학적 유의차가 인정되었다. 변이계수, 표현형 변이계수, 유전 변 이계수는 다소 높은 편이었으나 오차 또는 환경 변이계 수는 낮은 편이었다. 유전력은 대단히 높았고 유전자 전 이와 유전자 전이율은 중정도였다. 절화한 꽃을 화병에 꽂은 후 기간별로 생체중을 계측했을 때 품종 간 생체 중의 차이가 2배 이상에 달하였으며 품종 간 통계학적 유의차는 인정되었다. 변이계수, 표현형 변이계수, 유전 변 이계수는 비교적 높은 편이었으며 환경 또는 오차 변이 계수는 대단히 낮았다. 유전력은 대단히 높은 편이었고 유전자 전이는 낮은 편이었고 유전자 전이율은 중정도인 편이었다. 물의 누적 흡수량은 흡수량의 정도에 따라 3 개의 품종군으로 구분할 수 있었고 물의 흡수 속도는 1.5cm ~ 3.9cm/minute였으며 절화 수명은 ‘Pink Pride’가 21.3일로서 상당히 긴 편이었고 ‘Arctic Queen’이 9.3일 로서 대단히 짧았다. 물의 흡수량, 흡수 속도 및 절화 수 명 실험 결과, 모든 평균치의 품종 간 통계학적 유의차 가 인정되었다. 변이계수, 표현형 변이계수, 유전 변이계 수는 전반적으로 높은 편이었나, 오차 또는 환경 변이계 수는 낮았다. 유전력은 높은 편이었으나, 유전자 전이는 비교적 낮았다. 유전자 전이율은 중정도 또는 높은 경향 이었으나 특히 절화 2~3일째 수분 흡수량의 전이율은 100%이상으로 대단히 높았다.

Injection rate, injection quantity and injection timing of fuel are controlled precisely by electric control in CRDI system.Particularly, injection rate being influenced with injection pressure affects to spray characteristics and fuel-air ratio, so it is a very important factor in diesel combustion. In this study, injection rates in accordance with injection pressure at a constant ambient pressure were measured with Zeuch's method. Under the same condition, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. Injection start time and injection period were practically affected with injection pressure. Also, initial injection rate, spray penetration, spray angle and breakup of high density droplets region in the spray were affected with injection pressure. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for common rail direct injection system.

Lanthanum/gadolinium zirconate coatings are deposited via suspension plasma spray with suspensions fabricated by a planetary mill and compared with hot-pressed samples via solid-state reaction. With increase in processing time of the planetary mill, the mean size and BET surface area change rapidly in the case of lanthanum oxide powder. By using suspensions of planetary-milled mixture between lanthanum or gadolinium oxide and nano zirconia, dense thick coatings with fully-developed pyrochlore phases are obtained. The possibilities of these SPS-prepared coatings for TBC application are also discussed.

Yttria-stabilized zirconia (YSZ) coatings are fabricated via suspension plasma spray (SPS) for thermal barrier applications. Three different suspension sets are prepared by using a planetary mill as well as ball mill in order to examine the effect of starting suspension on the phase evolution and the microstructure of SPS prepared coatings. In the case of planetary-milled commercial YSZ powder, a deposited thick coating turns out to have a dense, vertically-cracked microstructure. In addition, a dense YSZ coating with fully developed phase can be obtained via suspension plasma spray with suspension from planetary-milled mixture of Y2O3 and ZrO2.

In this study, Cu-5Ni-10Sn(wt%) spinodal alloy was manufactured by gas atomization spray forming, and the microstructural features and mechanical properties of Cu-5Ni-10Sn alloy have been investigated during homogenization, cold working and age-hardening. The spray formed Cu-5Ni-10Sn alloy consisted of an equiaxed microstructure with a mixture of solid solution -(CuNiSn) grains and lamellar-structure grains. Homogenization at and subsequent rapid quenching formed a uniform solid solution -(CuNiSn) phase. Direct aging at from the homogenized Cu-5Ni-10Sn alloy promoted the precipitation of finely distributed ' or phase throughout the matrix, resulting in a significant increase in microhardness and tensile strength. Cold working prior to aging was effective in strengthening Cu-5Ni-10Sn alloy, which gave rise to a maximum tensile strength of 1165 MPa. Subsequent aging treatment slightly reduced the tensile strength to 1000-1100 MPa due to annealing effects.

YAG:Ce yellow phosphor particles were synthesized by spray pyrolysis with changing the solution properties and their luminous properties, crystal structure, and morphological changes were studied by using PL measurement, XRD, and SEM analysis. It was clear that the solution properties significantly affected the crystal phase, crystallite size, the PL intensity, and the morphology of YAG:Ce particles. At low calcination temperature, the addition of urea only to the spray solution was helpful to form a pure YAG phase without any impurity phases, as the result, the highest luminescence intensity was achieved at the calcination temperature of . When the calcination temperatures were larger than , however, the YAG particles prepared without any additive showed the highest luminescent intensity. Regardless of the solution conditions, the emission intensity of YAG:Ce particles prepared by spray pyrolysis showed a linear relation with the crystallite size. In terms of the morphology of YAG:Ce particles, the addition of both DCCA and to the spray solution was effective to prepare a spherical and dense structured YAG particles.

In this study, the researcher investigated the effects of water mist nozzle shape on water mist according nozzle shape angle(=30°, 45°, 60°, 75° and 90°). It was found that the water mist spray with nozzle When exit angle of water mist nozzle is =90° as result examining about spray special quality of water mist, velocity distribution was expose to maximum. And temperature distribution of target plate was looked tendency that range low. Water mist spray system that consider in this research is one of the most important utilities providing water mist in order to supply fire extinguishing.