• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.10
• /
• pp.1139-1146
• /
• 2004

The effect of triangular tabs attached at the perimeter of jet nozzle on heat transfer enhancement was investigated experimentally. The modified flow structure was visualized using a smoke-wire method. Four different types of jet nozzle having 0, 4, 6 and 8 tabs were tested at jet Reynolds number Re=15,000 to investigate the effect of tabs on the variation of heat transfer rate. The local and average Nusselt numbers are increased with increasing the number of tabs. At nozzle-to-plate distance of L/D=4, the average Nusselt number was increased about 9.9% at Re=15,000 in the impingement region for the case of 8 tabs attachment. As the nozzle-to-plate distance increases, however, the heat transfer enhancement effect of triangular tabs is reduced. For the case of 4 tabs, the heat transfer enhancement is not so distinctive at L/D=8. As the protrusion depth of tabs into the jet flow increases, the heat transfer rate is also enhanced when the nozzle-to-plate distance is smaller than L/D=6.

• Journal of Korean Society of Rural Planning
• /
• v.20 no.1
• /
• pp.37-49
• /
• 2014

With the globalized coming of the knowledge-based society following the post-industrial period, both the crises and opportunities have been occurring together as non-special affairs, which is the same situation in Rural Korea. A crucial key for maximization of potentialities of emerging opportunities is to mobilize the multi-valuedness embedded in rural areas as one of new growth powers. In order to realize a variety of multi-valuedness of rurality, it should be needed to re-discover and re-evaluate rural resources by paradigm shift and to identify the multi-valuedness of resources systematically and scientifically. On the basis of this understanding, this study aimed at setting up the evaluation indicators system by rural village types to identify systematically the multi-valuedness embedded in rural villages in the initial step. Integrated evaluation indicators system was made with 4-level hierarchies; high-leveled one with 3 fields(society, environment, regional economy); middle-leveled one with 8 areas; lower-leveled one with 19 sub-areas; detailed indicators totally with 39 items. These indicators were divided into 12 basic indicators applied to all types and 27 specialized indicators determining the characteristics of village types.

• Journal of computational fluids engineering
• /
• v.17 no.3
• /
• pp.39-44
• /
• 2012

In this study, a longitudinal pitch effect on in-line tube bank heat transfer has been analyzed numerically. To verify the accuracy of the solver model and boundary conditions, global Nusselt number(Nu) and pressure drop across the 2 row tube bank are compared with the existing experimental correlations under 500 ~ 2,000 Reynolds number(Re) range. By changing transverse pitch($S_T$) or longitudinal pitch($S_L$) separately in tube bank, we're trying to identify the each effect on heat transfer. We found that the effect of transverse pitch can be accounted for Reynolds number evaluated with maximum velocity($V_{max}$) at the smallest flow area similar to most existing correlations. Variation of the longitudinal pitch($S_L$) has a greater impact on the heat transfer compared to the transverse pitch($S_T$). Overall Nusselt number increases with larger longitudinal pitch($S_L$), however individual Nusselt number of the tube row has significant difference after the first row.

• Korean Journal of Medicinal Crop Science
• /
• v.13 no.5
• /
• pp.254-261
• /
• 2005

To evaluate the effects of cultivar, environment, age and cultivation times on ginsenoside content among 8 wild populations of American ginseng (Panax quinquefolium), the concentrations of 6 ginsenosides in root were determined at the time of collection (T0) of plants from the wild and 1 year after (T1) transplanting the roots to each of two different forest garden locations. Both location and population had significant effects on root and shoot growth. Overall, ginsenoside Rb1 was most abundant. The second most abundant ginsenoside were Re and Rg1, however the contents of them were not significantly different from each other. Concentrations of Rg1 and Re were inversely related. Ginsenoside Re was influenced by population and location. Ginsenoside Rg1, Rb1, Rc, Rb2 and Rd were influenced by population, location and age. Ginsenoside levels were consistently lower but growth was consistently higher at the more intensively managed garden location.

• Journal of the Korean Society of Industry Convergence
• /
• v.9 no.4
• /
• pp.247-253
• /
• 2006

Power consumption for double-stage paddle impeller in spherical and cylindrical agitated vessel was measured over a wide range of Reynolds number from laminar to turbulent flow regions. The power correlation was obtained which was applied to both spherical and cylindrical vessel, when the apparent diameter of the spherical vessel was equal to the diameter of the cylindrical vessel which had a height equal to its diameter and had the same volume as the spherical vessel. The power consumption for the double-stage impeller was dependent upon the distance of among the impeller in the agitated vessels, as follows: $$f/2={\frac{C_L}{Re_G}}+{\frac{Ct}{2}}({\frac{C_tr}{Re_g}}+Re_g)^{-m}$$

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.156.4-156
• /
• 2001

The uncertainties of an atmospheric re-entry flight with respect to stability and controllability are aerodynamic error, measurement error of the angle of attack, variation of dynamic pressure, wind, and trim position of the control surfaces, etc. During hypersonic flight, a future angle of attack is biased from a nominal schedule. In order words, because the angle of attack is estimated from the navigation data, estimation error occurs due to wind, atmospheric density variation, etc. Error models used in this study, include a standard deviation of +-3 sigma, and are the normal distribution of statistics. This paper shows the appraisement of tracking performance onto the reference trajectory, satisfaction of the initial condition of TAEM about the re-entry system.

• KIEAE Journal
• /
• v.4 no.2
• /
• pp.3-10
• /
• 2004

The purpose of this study is to suggest the guidelines for suitability analysis of the environmentally friendly rural village housing site. And then this study is based on the rural village model for the rural village (re)development. The suitability analysis of environmentally friendly rural village housing site is conducted on Suryon dong, Wonju, Gangwon-do. The method of analysis is to secure validaty and reliability of the exact analysis of a geographic data for a decision-making statistical analysis. The results of this study is useful to prove it conclusively site-suitability to establish a principles and to change direction for the environmentally friendly rural village and rural housing (re)development.

• Journal of the Korean housing association
• /
• v.2 no.1
• /
• pp.57-68
• /
• 1991

This study is concerned with the functions of dwelling space effected by the tendency that the number of furniture in the household has increased in recent years. The functions of dwelling space were grasped on the basis of dwelling - behavior tenitories. The possession of furniture was surveyed In 144 units of apartment house. Observation with questionnaire was carried out through pilot and main survey. 1) The dwelling - behavior territories of Anbang, Living Room and D.K. each were classified into 4 kinds. These territories were assorted into two categories ; first, the similar territories were integrated and specific various territories formatted, second, new kind dwelling spaces were required2) Accordingly, Anbang have to be re - setted up Anbang and storage, Living Room and D.K. re - setted up L.D.K. and Utility. In this way, it coudld be possible, that creative reasonable space were formated for more satisfactory. Therefore relationships between furniture possession and the usage of dwelling spaces wre identified.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.2
• /
• pp.176-183
• /
• 1999

This paper is aimed to investigate behaviour of vortex in 2-D step cavity with high Reynolds numbers$(3.2{\times}10^{3},\;10^{4},\;3{\times}10^{4},\;5{\times}10^{4}\;and\;7{\times}10^{4})$. The SOLA algorithm which is MAC type was adopted to solution method computing the flow field on irregular grid. In case of $Re=7{\times}10^{4}$ flow behavior is steady bu periodic unsteady sinusoidal fluctuation of local velocity and kinetic energy is found for $Re=10^{4}$ Continuous movements of small eddies in the secondary flow regions are discov-ered for $3{\times}10^{4}$ Generation of eddies and their active migrating behavior are detected over $Re=5{\times}10^{4}$ resulting in complete unsteady and non-linear flow characteristics Furthermore a typhoon-like vortex(TLV) appears intermittently and rotates along the separation regions and boundary layers.

• Korean journal of food and cookery science
• /
• v.26 no.1
• /
• pp.13-17
• /
• 2010

The antioxidant activity of commercial sweet persimmon wine concentrate (SPWC) was evaluated by determining the total phenol content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, reducing power (RP), and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities. TPC in the SPWC was $9.29{\pm}0.11\;mg$ gallic acid equivalents (GAE)/g, which corresponds to 31.59 mg GAE/100 mL of the wine. The IC50 for the DPPH radical scavenging activity, RP, and ABTS radical scavenging activity of SPWC were 2.96, 1.44, and 0.48 mg/mL, respectively. The neuroprotective effect of SPWC against glutamate-induced neurotoxicity in N18-RE-105 cells was investigated. Treatment of N18-RE-105 cells with various SPWC concentrations under glutamate resulted in the induction of a protective effect in a dose-dependent manner, as determined by the MTT reduction assay. These results suggest that SPWC exhibits considerable antioxidant and neuroprotective activity.