• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.2
• /
• pp.53-59
• /
• 1994

The characteristics of the shielded suspended substrate strip transmission line(SSSL) are analyzed by the point matching method and the variational method in Quasi-TEM mode. The accuracy of this solution is confirmed by analyzing and comparing this solution with the empirical solution obtained from the same dimension. The characteristic impedance and the effective dielectric constant are also studied by increasing the air-layer height of SSSL.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.11a
• /
• pp.276-277
• /
• 2002

One of drawbacks of the inertial impactor measurement is the required long sampling time (Keskinen et al., 1992). In a gravimetric method, an impaction substrate must be weighed and placed on the corresponding collection plate before being assembled. After sampling, the inertial impactor is disassembled and the collection plate is weighted again. The sampling time depends on the sampled particle mass because the collected particle mass must be sufficiently high to be measured by a sensitive microbalance. (omitted)

• Journal of Mushroom
• /
• v.20 no.3
• /
• pp.127-137
• /
• 2022

Effects of substrate bed interior environments on mushroom qualities were investigated in oyster mushroom cultivation facilities in which either Reversible Air-Circulation Fans (RACF) blowing air in two directions (upwards and downwards) or customary Convection Fans (CF) with air blowing only upwards were operated throughout the cultivation period. Two days before harvest, the deviation ranges of the bed interior temperature and relative humidity in the facility using RACF were in the ranges of 1.0-1.3℃ and 7.8-9.0% in the first growing cycle, and within 0.7-1.1℃ and 10.0-11.4% in the second cycle. In the facility using CF, the ranges of variation in the indoor environment parameters (5.8-6.4℃ and 21.3-23.1% in the first growing cycle, and 3.4-5.7℃ and 14.6-18.3% in the second growing cycle) were much enlarged compared to those associated with RACF. These results strongly indicate that RACF significantly enhances air uniformity. Some mushroom qualities differed between growing cycles. For instance RACF in the first cycle gave somewhat better qualities than CF, but some qualities, like pileus diameter and stipe length, were slightly lower than those described for CF in the second cycle when the cultivation substrate weakened. The observation that some qualities worsened under RACF conditions, despite better air uniformity during the growing cycle, revealed the possibility that downward wind may exert a non-negligible negative effect on mushroom growth. Therefore in the future, making wind measurements on the interior and exterior of substrate beds is necessary to obtain insights into their influences on mushroom qualities. The RACF operation manual needs to be edited to convey this necessity.

• Journal of People, Plants, and Environment
• /
• v.21 no.6
• /
• pp.445-460
• /
• 2018

Exposure to indoor air pollution is an emerging world-wide problem, with growing evidence that it is a major cause of morbidity worldwide. Whilst most indoor air pollutants are of outdoor origin, these combine with a range of indoor sourced pollutants that may lead to high pollutant levels indoors. The pollutants of greatest concern are volatile organic compounds (VOCs) and particulate matter (PM), both of which are associated with a range of serious health problems. Whilst current buildings usually use ventilation with outdoor air to remove these pollutants, botanical systems are gaining recognition as an effective alternative. Whilst many years research has shown that traditional potted plants and their substrates are capable of removing VOCs effectively, they are inefficient at removing PM, and are limited in their pollutant removal rates by the need for pollutants to diffuse to the active pollutant removal components of these systems. Active botanical biofiltration, using green wall systems combined with mechanical fans to increase pollutant exposure to the plants and substrate, show greatly increased rates of pollutant removal for both VOCs, PM and also carbon dioxide ($CO_2$). A developing body of research indicates that these systems can outperform existing technologies for indoor air pollutant removal, although further research is required before their use will become widespread. Whilst it is known that plant species selection and substrate characteristics can affect the performance of active botanical systems, optimal characteristics are yet to be identified. Once this research has been completed, it is proposed that active botanical biofiltration will provide a cheap and low energy use alternative to mechanical ventilations systems for the maintenance of indoor environmental quality.

• Korean Journal of Chemical Engineering
• /
• v.36 no.6
• /
• pp.975-980
• /
• 2019

Infrared (IR) spectroscopy is a powerful technique for observing organic molecules, as it combines sensitive vibrational excitations with a non-destructive probe. However, gaseous volatile compounds in the air are challenging to detect, as they are not easy to immobilize in a sensing device and give enough signal by themselves. In this study, we fabricated a thin nanocrystalline metal-organic framework (nMOF) film on a surface plasmon resonance (SPR) substrate to enhance the IR vibration signal of the gaseous volatile compounds captured within the nMOF pores. Specifically, we synthesized nanocrystalline HKUST-1 (nHKUST-1) particles of ca. 80 nm diameter and used a colloidal dispersion of these particles to fabricate nHKUST-1 films by a spin-coating process. After finding that benzene was readily adsorbed onto nHKUST-1, an nHKUST-1 film deposited on a plasmonic Au substrate was successfully applied to the IR detection of gaseous benzene in air using surface-enhanced IR spectroscopy.

• Microbiology and Biotechnology Letters
• /
• v.7 no.4
• /
• pp.211-216
• /
• 1979

Air lift fermentor (ALF) is widely used for production of single-cell protein (SCP) from hydrocarbon and other carbon sources, because oxygen transfer efficiency is believed to be superior in the ALF to that in other conventional fermentors. However, the performance of ALF in terms of mixing is somewhat questionable. In this research, we studied about the performance of the ALF in SCP production using methanol fermentation process as a model system. The results show that ALF could be employed for SCP production or other fermentation processes when substrate is miscible and used at low concentration. With a high substrate concentration, it must be operated under high pressure or low dilution rate to meet the adequate oxygen transfer requirement.

• KIEAE Journal
• /
• v.13 no.5
• /
• pp.67-77
• /
• 2013

Based on the increasing demand for a solution to reduce thermal load, extensive green roofs have great opportunity for application to existing roofs due to their light-weight and easy maintenance. The present study delivers data regarding thermal behavior and heat reduction potential in relation to vegetation coverage between green roof types. 1) In the hottest hour in a day, green roofs showed considerable potential to mitigate heat load in roof environments, which can be up to $10^{\circ}C$ difference. 2) Compared to conventional cement roofs, the extensive green roofs only have a slight potential to cool the air over green roofs. By statistical analysis of linear regression, green coverage has little to do with the reduction of air temperature; the cooling effect was proven only in nighttime. 3) Green roofs act as an insulating roof membrane, the inner substrate of green roofs remained cooler than cement roof surfaces in the daytime, but in the nighttime the green roofs generally were warmer than the cement roof surfaces. 4) The variable of vegetation coverage resulted in no significant difference in thermal behavior in the air, but had the greatest effect in keeping the substrate cool in the daytime. The high vegetation coverage also hindered the rapid cooling of the substrate in the nighttime, and therefore was warmer than other measured temperatures. In order to draw a clear conclusion to combat urban heat island effect with extensive green roofs, the experiment needs to be applied on a larger scale.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.3
• /
• pp.335-342
• /
• 2013

In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.2
• /
• pp.257-262
• /
• 2008

In this paper, the key parameters of $CO_2$ laser(focus depth, air blow rate, total laser beam time, number of pulse) are experimented for thru-hole and scribing line on AIN(aluminum nitride) substrate with high thermal conductivity. And, microstrip line & spiral planar inductor are fabricated on AIN substrate using 5 um Cu-plating with self-masking technique. The microstrip line of AIN has 0.1 dB/mm attenuation at 10 GHz and 6 nH spiral planar inductor has 56 maximum quality factor at 1 GHz. Thus, the AIN substrate is promising for GHz applications of high power area.

• Journal of Bio-Environment Control
• /
• v.24 no.3
• /
• pp.243-251
• /
• 2015

This study aimed to determine the effects of root zone cooling using air duct on air temperature distribution and root zone and leaf temperatures of sweet pepper (Capsicum annum L. 'Veyron') grown on coir substrate hydroponic system in a greenhouse. When the air duct was laid at the passage adjacent the slab, the direction of air blowing was upstream at $45^{\circ}$. The cooling temperature was set at $20^{\circ}C$ for day and $18^{\circ}C$ for night. For cooing timing treatments, the cooling air was applied at all day (All-day), only night time (5 p.m. to 1 a.m.; Night), or no cooling (Control). The air temperature inside the greenhouse at a height of 40 and 80cm above the floor, and substrate and leaf temperatures, fruit characteristics, and fruit ratio were measured. Under the All-day treatment, the air temperature was decreased about $4.4{\sim}5.1^{\circ}C$ at the height of 40cm and $2.1{\sim}3.1^{\circ}C$ at the height of 80cm. Under the Night treatment, the air temperature was decreased about $3.4{\sim}3.8^{\circ}C$ at the height of 40cm and $2.2{\sim}2.7^{\circ}C$ at the height of 80cm. The daily average temperature in the substrate was in the order of the Control ($27.7^{\circ}C$) > Night ($24.1^{\circ}C$) > All-day ($22.8^{\circ}C$) treatment. Cooling the passage with either upstream blowing at $45^{\circ}$ or horizontal blowing at $180^{\circ}$ was effective in lowering the air temperature at a height of 50cm; however, no difference at a height of 100cm. Cooling the passage with perpendicular direction at $90^{\circ}$ was effective in lowering the air temperature at the height between 100 and 200cm above the floor; however, no effect on the temperature at the height of 50cm. A greater decrease in leaf temperature was found at 7 p.m. than that at 9. a.m. under both All-day and Night treatments. Fresh weight partitioning of fruit was in the order of the All-day (48.6%) > Night (45.6%) > Control (24.4%) treatment. A higher fruit production was observed under the All-day treatment, in which the accumulated average temperature was the lowest, and it may have been led to a higher proportion of photosynthate distributed to fruit than other treatments.