• Title/Summary/Keyword: Uniformity of Spray

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Study on Experimental Verification of Uniform Control using Agricultural Drone (농업용 방제 드론을 이용한 균일 방제에 관한 실험적 검증)

  • Wooram Lee;Sang-Beom Lee; Jin-Teak Lim
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.2
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    • pp.575-580
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    • 2023
  • This study was prevent the decrease in crop output by insect pests and spraying by application uniformity. A flight level 4 m height and 4-5 m/sec. speed are difficult to maintain with a agricultural drone for aerial application, which has been affected by the methods or environmental factors, such as changes in the wind. Therefore, which can allow a controlled application width and spray rate automatically and verified experimentally using drone. The sprayed particles began to decrease from about 3.75 m on the left and right sides of the spray nozzle. According to the number of particles, the effective spraying width was observed to be about 7.5 m, and it was verified that the proposed spraying system was effective in uniform control system.

A Study on the Macro-Scopic Spray Characteristic of Homogeneous Degree for the GDI Injector According to Mixture(Gasoline-Diesel) Ratio Using Mie-Scattering Method and the Entropy Analysis (Mie 산란 방법과 엔트로피 해석 방법을 이용한 혼합연료비에 따른 분무 균질도 특성에 관한 연구)

  • Lee, Chang-Hee;Lee, Ki-Hyung;Lee, Chang-Sik;;Bae, Jae-Il
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.1
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    • pp.69-75
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    • 2003
  • In this study, his technique was applied to a GDI spray in order to investigate the mixture distribution. In addition, the homogeneity degree and diffusion effect according to ambient temperature in the high pressure chamber were analyzed by using an entropy analysis method. From this experiment, we could find that entropy analysis is very effective method for the analysis of mixture formation, and the entropy values increase with the progress of uniformity in diffusion Process. we tried to provide the fundamental data for parameter which effects on the spray macroscopic characteristics with mixture ratio of diesel and gasoline. In addition, the mixture formation was analyzed by using entropy analysis. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. From the entropy analysis results we could find that the direct diffusion phenomena is a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially in vaporizing conditions. As to increasing ambient temperature and increasing gasoline rate, the entropy intensity using the statistic thermodynamics method is increased because evaporation rate is higher gasoline than diesel.

The Prediction of Etching Characteristics Using Monte-Carlo Simulation in Etching Process of Lead-Frame (Lead-Frame 에칭공정에서 몬테카를로 시뮬레이션을 이용한 에칭특성 예측)

  • Jeong Heung-Cheol;Choi Gyung-Min;Kim Duck-Jool
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.1 s.178
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    • pp.72-79
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    • 2006
  • The objective of this work is to simulate the etching characteristics for the optimization on the etching process of Lead-Frame. The etching characteristics such as etching factor, etching uniformity were investigated under different the actual operating conditions. The correlation between the etching characteristics and the spray ones were analyzed to simulate the etching characteristics in the etching process. To improve the etching characteristics in the etching process, effects of the various operating conditions such as pressure, distance from nozzle tip, pipe pitch, and feed speed should be understood in detail. The spray characteristics obtained by experiment using PDA system were simulated by the Monte-Carlo simulation. The etching process model was coded by Java language. It was found that the spray characteristics were correlated with the etching ones and simulation results generally agreed well with the measured results of etching characteristics in the etching process of Lead-Frame. The optimal operating parameters were successfully found under variable conditions.

Flow Analysis of PM/NOX Reduction System for Emergency Generator (비상발전기용 PM/NOX 저감장치의 유동특성 연구)

  • Bang, Hyo-Won;Park, Gi-Young;Lee, Seong-Wock
    • Journal of ILASS-Korea
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    • v.26 no.4
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    • pp.163-170
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    • 2021
  • Emergency generators normally use diesel engines. The generators need to conduct weekly no-load operation inspections to ensure stable performance at emergency situations. In particular, the generators with large diesel engines mainly use rectangle type filter substrates. In order to minimize hazardous emissions generated by generators, optimizing the reduction efficiency through CFD analysis of flow characteristics of PM/NOX reduction system is important. In this study, we analyzed internal flow by CFD, which is difficult to confirm by experimental method. The main factors in our numerical study are the changes of flow uniformity and back pressure. Therefore, changes in flow characteristics were studied according to urea injector locations, selective catalyst reduction (SCR) diffuser angle, and filter porosity.

Fabrication of Carbon Nanotube Strain Sensors (카본나노튜브 스트레인 센서 제작 기술)

  • Chang, Won-Seok;Song, Sun-Ah;Kim, Jae-Hyun;Han, Chang-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.10
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    • pp.773-777
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    • 2009
  • In this study, the strain sensing characteristics of single-wall carbon nanotubes(SWCNTs) networks were investigated to develop a film sensor for strain sensing. The SWCNTs film are formed on flexible substrates of poly(ethylene terephthalate) (PET) using spray process. In this manner we could control the transparency and obtain excellent uniformity of the networked SWCNT film. The carbon nanotube film is isotropic due to randomly oriented bundles of SWCNTs. Using experimental results it is shown that there is a nearly linear change in resistance across the film when it is subjected to tensile stress. The results presented in this study indicate the potential of such films for high sensitive transparent strain sensors on macro scale.

Fabrication of transparent conducting films of carbon nanotubes using a spray method

  • Geng, Hong Zhang;Lee, Kyu;Song, Young-Il;Kim, Gil-Yong;Choi, Ha-Kyu;Jun, Bae-Jung;Ahn, Kay-Hyeok;Lee, Young-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.525-528
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    • 2006
  • Transparent conducting films were fabricated on polyethylene terephthalate substrate by a spray method using double-walled carbon nanotubes dispersed in organic solvent and water-based solution. We analyzed the films by absorption spectra, sheet resistance, and scanning electron microscopy. Transparent conducting films with high uniformity and high transparency were fabricated by the spray method. We found that the dispersion particularly nanodispersion of CNTs was of crucial importance to improve the film performance.

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Coverage Distribution of Blasted Droplets by an Orchard Sprayer (과수방제기 살포입자의 도포율 분포특성)

  • 구영모;김상헌;신범수
    • Journal of Biosystems Engineering
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    • v.26 no.4
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    • pp.355-362
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    • 2001
  • Uniform application of agri-chemicals will improve orchard pest management. An air-blast(orchard) sprayer designed for vineyards has been used: however, few research on the uniformity and coverage of the sprays has been reported. Distributions of spray coverage were measured with artificial targets and analyzed to enhance the efficiency of spray application. A structure was built to place water sensitive papers, sampling spray droplets blasted from the orchard sprayer. The sampling cards were collected from five directions at three distances (2.5, 3.0 and 3.5m) for two fan speeds (2,075 and 3,031 rpm), and analyzed using an image analysis system. The distribution of the coverage percent area did not follow the wind velocity pattern. The coverage by the low fan speed was more uniform and higher than that by the higher fan speed. The coverage percent area decreased with an increase of distance. The distribution of droplet density was similar to that of coverage. However, the coverage contribution by smaller droplets became more significant as the distance increased. The upward blasting distance was limited within 3m, but the limit to the ground level was expanded the distance more than 3.5m because of the concentrated droplets.

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Effect of Slurry Flow in Spray Slurry Nozzle System on Cu CMP (스프레이 슬러리 노즐 시스템에서 슬러리 유동이 Cu CMP에 미치는 영향)

  • Lee, Da Sol;Jeong, Seon Ho;Lee, Jong Woo;Jeong, Jin Yeop;Jeong, Hae Do
    • Journal of the Korean Society for Precision Engineering
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    • v.34 no.2
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    • pp.101-106
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    • 2017
  • The chemical mechanical planarization (CMP) process combines the chemical effect of slurry with the mechanical effect of abrasive (slurry)-wafer-pads The slurry delivery system has a notable effect on polishing results, because the slurry distribution is changed by the supply method. Thus, the investigation of slurry pumps and nozzles with regard to the slurry delivery system becomes important. This paper investigated the effect of a centrifugal slurry pump on a spray nozzle system in terms of uniform slurry supply under a rotating copper (Cu) wafer, based on experimental results and computational fluid dynamics (CFD). In conventional tools, the slurry is unevenly and discontinuously supplied to the pad, due to a pulsed flow caused by the peristaltic pump and distributed in a narrow area by the tube nozzle. Adopting the proposed slurry delivery system provides a higher uniformity and lowered shear stress than usual methods. Therefore, the newly developed slurry delivery system can improve the CMP performance.

An Experimental Study on the Effects of the Shape of a Drencher Head on the Characteristics of a Water Curtain (드렌처 헤드의 형상에 따른 수막특성에 관한 실험적 연구)

  • Lee, Seung-Chul;Kim, Bong-Jun;Lee, Jae-Ou;Park, Chung-Hwa;Hwang, Cheol-Hong
    • Fire Science and Engineering
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    • v.30 no.3
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    • pp.86-93
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    • 2016
  • The effects of the shape of a drencher head on the flow characteristics and radiation attenuation of a water curtain, in order to prevent a fire spread, were experimentally studied. The distance (h) between the orifice exit and deflector and the diameter of deflector (D) were varied as the shape factors of the head, with the same orifice diameter (d). It was found that an increase in h leads to an increase in the water flow rate and spray angle. However, the change in the spray angle decreases with increasing D. Increasing D brings about a subtle increase in the water flow rate and a significant decrease in the spray angle. A larger value of D makes it possible to produce a flatter pattern of the water curtain, but reduces the uniformity of the droplets inside the spray angle. The mean droplet diameter decreases significantly as the operating pressure increases. However, the variation in the shape of the drencher head does not significantly affect the change in the mean diameter at the same operating pressure. Finally, it was found that the radiation attenuation afforded by the water curtain at the same operating pressure was affected by water flow rate and droplet uniformity, which were determined by h and D, respectively.

Development of Numerical Model for Predicting Deposition Thickness Distribution during Spray Process for Carbon Nanotube Thin Films (탄소나노튜브 박막 제조를 위한 분무공정에서의 증착 두께 분포 예측 모델 개발)

  • Choi, Du-Soon;Kim, Duck-Jong;Jang, Dong-Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.9
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    • pp.969-974
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    • 2011
  • A carbon nanotube (CNT) is a cylindrical carbon nanostructure with good transport properties along the tube's axis. As an approach for realizing the practical use of CNTs, CNT networks are fabricated and their applications in many fields are investigated. To fabricate thin CNT-based films, several methods have been proposed and used. Among these methods, the spray coating method is a robust method for fabricating a large area. However, it is difficult to achieve uniformity in the CNT network. To solve this problem, it is necessary to understand the effect of the sprayprocess parameters on the deposition thickness distribution. In this study, a numerical model for predicting the deposition thickness distribution during the spray process was developed. The spatial deposition thickness distributions obtained according to various nozzle paths were analyzed using the developed numerical model.