• Journal of Korean Society for Atmospheric Environment
• /
• v.18 no.1
• /
• pp.59-65
• /
• 2002

The application of local air circulation models in the field of air pollution research has become more and more popular with increasing demands of detailed wind data for obtaining precise information on spatial and temporal variations. However the prediction of air circulation near the surface is generally not a simple task because of intricate interactions between surface and air. Particularly in Korea, many areas are mountainous with a complicated shoreline. Because considerable errors could be introduced into the model predictions, it is necessary to confirm their feasibility by comparing model predictions with observations. In this paper, the results from the evaluation of model predictions in selected publications in Korea as well as their procedures were reviewed. Various aspects of errors in the model predictions. such as possible sources, vulnerable conditions, and reduction methods, were discussed.

• Journal of Ocean Engineering and Technology
• /
• v.14 no.3
• /
• pp.46-54
• /
• 2000

Three dimensional numerical experiments that included the land-use transformation by the large scale reclamation were used to investigate the mesoscale air flow over the coastal regions. In this paper the surface temperature of the inland was determined through the surface heat budget consideration with inclusion of a layer of vegetation. The vertical diffusion coefficients of momentum, heat and specific humidity in the constant flux layer were taken from the Mellor and Yamada(1975). It has shown that the resulting model is able to reproduce the air circulation in coastal regions, and the simulated characteristics agree with the known properties of this circulation. A series of numerical experiments were then carried out to investigate the diurnal response of the air flow to various types of surface inhomogeneities.

• KSBB Journal
• /
• v.22 no.2
• /
• pp.91-96
• /
• 2007

The saccharogenic liquid (SFW) obtained by the enzymatic saccharification of food wastes was used as a medium for production of bacterial cellulose (BC). The enzymatic saccharification of food wastes was carried out by the cultivation supernatant of Tricoderma inhamatum KSJ1 culture. Acetobacter xylinum KJ1 was employed for the BC production culture. Under the scaled-up aeration condition of 1.0 vvm, 5.64 g/L of BC was produced in 3 days cultivation in 50 L air circulation bioreactor using SFW medium with addition of 0.4% agar. The productivity was similar to that of 10 L air circulation bioreactor (5.84 g/L). This cultivation method with 50 L air circulation bioreactor decreasing shear stress and increasing oxygen transfer coefficient ($k_La$) was very useful in BC mass production. The physical properties, such as morphology, molecular weight, crystallinity, and tensile strength of BC produced by the static culture (A), the air circulation culture using 10 L bioreactor (B) and 50 L bioreactor (C) were investigated. The number average molecular weight of BCs produced under the different culture conditions (A-C) showed 2,578,000, 1,975,000, and 1,809,000, respectively. Tensile strength was 1.72 $kg/mm^2$, 1.19 $kg/mm^2$, and 1.18 $kg/mm^2$, respectively. All of the BCs had a form of cellulose I representing pure cellulose. The relative degree of crystallinity showed the range of 86.2$\sim$87.8%. BC production by the air circulation culture mode brought more favorable results in terms of the physical properties and its ease of scale-up. Therefore, it is expected that the new BC production method, the air circulation culture using SFW, would contribute greatly to BC-related manufacturing.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1925-1930
• /
• 2006

A quasi depth-varying mathematical model for wind-generated circulation in coastal areas, expressed in terms of the depth-averaged horizontal velocity components and free surface elevation was validated and used to understand the diurnal circulation process. The wind velocity is considered as a dominant factor for driving the wind generated current. In this paper, three dimensional numerical experiments that included the land topography were used to investigate the mesoscale air flow over the coastal regions. The surface temperature of the inland was determined through the surface heat budget consideration with inclusion of a layer of vegetation. A series of numerical experiments were then carried out to investigate the diurnal response of the air flow and wind-generated circulation to various types of surface inhomogeneities.

• Air Cleaning Technology
• /
• v.12 no.1 s.44
• /
• pp.81-86
• /
• 1999

• Journal of Bio-Environment Control
• /
• v.10 no.1
• /
• pp.23-29
• /
• 2001

This experiment was conducted to investigate to investigate the effect of air circulation and forced ventilation of greenhouse on the development of fermented fruits in an oriental melon. An air circulation system and a forced ventilation system were operated during 09:30~17:00 at a 15 min. interval from Apr. 6, 5 days after fruit setting, to Jun. 29, everyday except rainy days. Wind velocities in the greenhouse were 0.06~0.08, 0.24~0.32, and 0.60~0.72m.s$^{-1}$ in the naturally ventilated (control), in the air circulated, and including leaf length and width, were observed between treatments. However, the amount of xylem exudate increased in the air circulated treatment as compared to the control. Percent of fermented fruits significantly decreased in the air circulated treatment as compared to the control. The forced ventilation treatment showed no significant difference in percent of fermented fruits as compared to the control or to the air circulated treatment.

• Journal of Bio-Environment Control
• /
• v.8 no.2
• /
• pp.99-107
• /
• 1999

The experiment was conducted to investigate the relationship between $Ca^{2＋}$ uptake and development of fermented fruit through the forced-air circulation of ambient fruit. Air circulation of ambient fruits were adjusted with 0.3m/sec wind velocity for three hours a day from 10：00 to 13：00. Treatments consisted of 0, 10 day, 20 day, 30 day of forced air circulation of ambient fruit. Although the results varied depend on the duration forced air circulation, in general, treated fruit increased fruit weight, flesh thickness, fruit hardness, soluble solids, and chromaticity, and decreased the number of fermented-fruit. $Ca^{2＋}$ content in fruit.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.33 no.11
• /
• pp.1806-1816
• /
• 2009

This study analyzes the efficiency of a solar cell attached to an air circulation jacket. A commercially available silicon solar panel was selected and attached at four spots where the body angle was $40-60^{\circ}$ and voltage ($V_{oc}$, V), current ($I_{sc}$, A), and output power (P, W) were measured to determine the efficiency. The solar panel was applied to the outer jacket that operates with two fans to increase the convection that lowers the body temperature. The heavy work of standing, walking, and sweeping of a street sweeper was simulated in the field test. The microclimate within the jacket (with or without a fan) was measured and the subjective thermal, humidity, and comfort sensations were surveyed. SPSS 12.0 statistical package was used for a t-test and Wilcoxon signed-rank test. The results show that the highest efficiency of the solar cell was at the incident angle of $60^{\circ}$ in terms of voltage, current and output power distribution. The microclimate temperature of the air circulation jacket decreased significantly with the high power of the fan and subjects felt cooler than the jacket with a fan at the incident angle of $60^{\circ}$. Air circulation jackets operated by a silicon solar panel showed a significant cooling effect on the wearers.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.250-254
• /
• 1998

This paper shows how the environmental parameters(temperature, humidity) in the greenhouse are influenced by air movement produced by air circulation fans. When the fans were used, they could make indoor temperature and humidity homogenious, but there was no significant difference in the location and number of fans. When the fans were not used during the night time, there was no significant difference in the temperature and humidity, but the standard deviation was reduced by using the fans.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.19 no.4
• /
• pp.225-232
• /
• 1990