• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.5
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• pp.691-699
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• 1997

The effects of concave hemispherical surface curvature on the local heat transfer from a turbulent round impinging jet were experimentally investigated. The liquid crystal transient method was used for these measurements. This method, which is a variation on the transient method, suddenly exposes a preheated wall to an impinging jet while video recording the response of liquid crystals for the measurement of the surface temperature. The Reynolds number ranges from Re=11,000 to 50,000, the nozzle-to- surface distance from L/d=2 to 10, and the surface curvature from D/d=6 to 12.The present results are also compared to those for the flat plate case. In the experiment, the local Nusselt numbers tend to increase in all regions with an increasing surface curvature. The maximum Nusselt number for all Reynolds numbers occurred at L/d .ident. 6 and a second maximum in the Nusselt number occurred at R/d .ident. 2 for both Re=23,000 and Re=50,000 in the case of L/d=2 and for Re=50,000 only in the case of L/d=4. Meanwhile, as the surface curvature increases, the value of the secondary maximum Nusselt number decreases. All the other cases exhibit monotonically decreasing values of the Nusselt number along the curved surface. The stagnation point Nusselt numbers are well correlated with Re, L/d, and D/d.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.3
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• pp.22-30
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• 2011

There is a many way of LPRE throttling methods, high-pressure-drop systems, dual-manifold injector, gas injection, multiple chambers, pulse modulation and movable injector components. Especially dual-manifold injector is essentially combines two fixed-area injectors into a common structure, with independent feed systems controlling flow to each injector manifold. In this paper, using indirect photography and liquid film thickness measurement with various injection pressure and tangential entry diameter to decide stability of spray over a wide thrust range in dual manifold injector.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.148-153
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• 1995

Glyphosate (N-[phosphonomethyl]glycine) applied to the assimilate-exporting leaves or sprayed to the whole plants of tomato(Lycopersicon esculentum Mil var. Moneymaker) induced the rapid inhibition of 5-enolpyruvyl skimic acid 3-phosphate synthase(EPSP-synthase). It shows that EPSP-synthase activity precedes chlorophyll loss. There is no difference in EPSP-synthase activity between in vivo tomato meristem and cell suspension culture if glyphosate is not applied. The EPSP-synthase activity is in a range of 4 to 6 nkat per mg protein. The inhibition of EPSP-synthase action is induced within 36 h after glyphosate application while the Chl contents were reduced 48 h after the application. In cell suspension culture of tomato and Corydalis (Corydalis sempervirens), a sublethal concentration of glyphosate retards the fresh weight increase and prolonged lag phase. The fresh weight is reached maximal about 14 days after the subculture in the presence of glyphosate. The inhibitory effect of glyphosate on EPSP-synthase is remarkably induced in lag phase.