• Title/Summary/Keyword: Droplet volume

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Enhancement of Physical Properties and Efficacy of Pesticide Spray Solution by Addition of Adjuvants (Adjuvant에 의한 농약살포액의 물리성 개선 및 약효증진 효과)

  • Jin, Yong-Duk;Lee, Hee-Dong;You, Oh-Jong;Kim, Jin-Bae;Kwon, Oh-Kyung
    • The Korean Journal of Pesticide Science
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    • v.12 no.4
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    • pp.421-428
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    • 2008
  • This study was carried out to elucidate the effects of adjuvants on physicochemical properties and pest control efficacy of pesticide spray solution. Spray droplet sizes of pesticide solution decreased by addition of adjuvants even though its effect varied according to the pesticides. The adhesive effect of pesticides sprayed on target crops by addition of adjuvants varied according to the properties, the application methods, and the spray volume of pesticides. Wash-off of the deposited amount of active ingredients of the solution of tricyclazole WP and fenobucarb EC by simulated rainfall after spraying on rice plants dramatically reduced by adding adjuvants. The retained amount of active ingredients of the pesticides were $1.5{\sim}4.1$ times higher than those without adjuvants when subjected to simulated rainfall 6 hours after spraying. Addition of adjuvants to the propanil EC spray solution enhanced the control efficacy in barnyard grass, Echinocloa crus-galli Beauv. by $8{\sim}30%$, which showed a potential to reduce pesticide use.

Effect of Nozzle Shape and Injection Pressure on Performance of Hybrid Nozzle (노즐 형상 및 분사 압력이 하이브리드 노즐 성능에 미치는 영향 연구)

  • Ro, Kyoung-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.74-79
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    • 2017
  • The fire extinguishing performance of hybrid nozzle systems is improved by injecting an extinguishing agent concentrically into the target site and, in this study, water mist is used as a water curtain to confine the droplets of the agent. In this study, we numerically investigated the effect of the foundation angle and injection pressure on the performance of a hybrid nozzle by evaluating the mean radius of the volume fractions of the agent and water mists. An experiment involving a water mist nozzle was carried out to validate the numerical method and then the droplet behaviors, e.g., stochastic collision, coalescence and breakup, were calculated with 2-way interaction Discrete Particle Modeling (DPM) in the steady state for the hybrid nozzle system. The mean radius of the water mists increased by about 40 %, whereas that of the agent decreased by about 21 %, when the injection pressure was increased from 30 bar to 60 bar. In addition, the mean radius of the agent increased by about 24 % as the foundation angle of the hybrid nozzle head increased from $30^{\circ}$ to $60^{\circ}$. As a result, it can be inferred that the injection angle and pressure are important factors for hybrid water mist designs.

The effect of solvent evaporation of dentin adhesive on bonding efficacy (상아질 접착제의 용매 증발이 접착 효율에 미치는 영향)

  • Cho, Min-Woo;Kim, Ji-Yeon;Kim, Duck-Su;Choi, Kyoung-Kyu
    • Restorative Dentistry and Endodontics
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    • v.35 no.5
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    • pp.321-334
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    • 2010
  • Objectives: The purpose of this study is to evaluate bonding efficacy by means of measuring the effect of remained solvent on Degree of conversion(DC) and ${\mu}TBS$ and FE-SEM examination. Materials and Methods: Two 2-step total etching adhesives and two single-step self etching adhesives were used in this study. First, volume weight loss of 4 dentin adhesives were measured using weighting machine in process of time in normal conditions and calculate degree of evaporation (DE). Reaction/reference intensity ratio were measured using micro-Raman spectroscopy and calculate DC according to DE. Then 2 experimental groups were prepared according to air-drying methods (under, over) and control group was prepared to manufacturer's instruction. Total 12 groups were evaluated by means of micro tensile bond strength and FE-SEM examination. Results: Degree of evaporation (DE) was increased as time elapsed but different features were observed according to the kind of solvents. Acetone based adhesive showed higher DE than ethanol and butanol based adhesive. Degree of conversion (DC) was increased according to DE except for $S^3$ bond. In ${\mu}TBS$ evaluation, bond strength was increased by additional air-drying. Large gaps and droplets were observed in acetone based adhesives by FE-SEM pictures. Conclusions: Additional air-drying is recommended for single-step self etching adhesive but careful consideration is required for 2-step total etching adhesive because of oxygen inhibition layer. Evaporation method is carefully chose and applied according to the solvent type.

Effects of Magnolia Officinalis Bark Extract on Improvement of Lip Wrinkles (요엽후박나무 추출물의 입술 주름 개선에 대한 연구)

  • Lee, Seonju;Kim, Mina;Park, Sung Bum;Kim, Ki Young;Park, Sun-Gyoo;Kim, Mi-Sun;Kang, Nae-Gyu
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.45 no.1
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    • pp.95-103
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    • 2019
  • Lips have a defect in maintenance of moisture due to their thin layer. As aging progresses, lips lose volume and redness, and become wrinkled. Fat grafting and filler surgery have been used to achieve attractive lips, but little research has been reported to develop better materials to replace the present methods. Recently, a study suggests that the increase of adipocyte number can be enhancing the expansion endogenous fat. In previous study, we identified that the efficacy of Magnolia officinalis bark extract (MOBE) was effective on the induction of adipogenic differentiation. In this study, we confirmed that MOBE enhanced the differentiation of human adipose-derived stem cells on the fat mimic 3D structure built by 3D bioprinting method From further experiments in human, we established a method to quantify the severity of lip wrinkle by measurement of standard deviation of gray value using Image J software. Finally, we found that topical treatment with 1% MOBE formulated lip balm significantly improved the lip wrinkle after using for 12 weeks. In conclusion, these findings suggest that MOBE has great potential, as a cosmetic ingredient, to reduce the lip wrinkle through the effect of promoting adipogenic differentiation.