• KIEAE Journal
• /
• v.7 no.5
• /
• pp.65-71
• /
• 2007

The purpose of this study was to analyze the difference of thermal sensation by radiant floor heating as ecological design element. The experimental investigations were carried out in climate chamber, and subjects were 34 college-age females in good health. The experimental variable was radiant heat by floor heating, and experimental controlled conditions were indoor temperature, relative humidity, and air velocity in climate chamber and clothing value and activity of subjects. The results are as follows. (1) Indoor temperature($21{\pm}0.5^{\circ}C$) in climate chamber were maintained as controlling. Clothing values of the subjects were controlled as average 0.73 clo. In the floor heating-off, globe temperature was average $23.2^{\circ}C$(22.4~24.1), but in the floor heating-on, globe temperature was average $24.8^{\circ}C$(23.0~25.5). (2) In the floor heating-off, thermal sensation rating was average -1.03(slightly cool), in the floor heating-on, thermal sensation rating was average +1.03(slightly warm). (3) There were the differences of thermal sensation by radiant floor heating although indoor temperatures were maintained in an equal state. (4) The thermal sensation rating was tending upward according as the globe temperature was getting higher.

• Journal of Korean Society for Atmospheric Environment
• /
• v.26 no.1
• /
• pp.77-84
• /
• 2010

The diffusion and partition coefficients of polyurethane foam (PUF) are estimated using a microbalance experiment and small chamber test. The microbalance is used to measure sorption/desorption kinetics and equilibrium data. When the diffusion condition is controlled in the chamber of the sample, interactions between volatile organic compounds (VOCs) and PUF can lead to the estimation of a relatively homogenous rate of mass transfer in the interiors and surfaces of PUF. The estimates of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) are shown to be independent of the concentrations of VOCs. This approach, if applied to a diffusion-controlled or physically-based model, can facilitate more precise prediction of their source/sink behavior. Although further research and more rigorous validation is needed, an emission model applied with the diffusion and partition coefficients from this research holds promise for the improvement of reliability in predicting the behavior of VOCs emitted from porous building materials by D and K.

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.4
• /
• pp.225-234
• /
• 2012

The anechoic chamber is essential tool to measure the various acoustic parameters with high precision. The chamber provides the climate controlled indoor environments but requires the dedicated room at a great cost in order to isolate and absorb sound field. Provided the purpose of the chamber is specific to the experiments of sound localization, the performance requirements excluding free field can be alleviated for cost effective solution. This paper designs low cost and profile anechoic chamber based on acoustic pyramids and evaluates the performance specified by the Annex of ISO 3745. Data analysis is employed to measure the free and hemi-free field performance over five straight paths for working areas and four paths for non-working areas. The identical two measurement campaigns were conducted for free and hemi-free field chamber which is easily interchangeable by simple labor in this chamber design. In the working area with conventional speaker, the results of these analyses demonstrate that lab-designed anechoic chamber is in conformance with ISO 3745 for 250 Hz - 16 kHz one-third octave band at free field chamber and for 1 kHz - 16 kHz one-third octave band at hemi-free field chamber.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.4
• /
• pp.374-380
• /
• 2010

This experiment was carried out to investigate the effect of light qualities and lighting types provided by LED Chamber System which designed by Rural Development Administration on growth and development of Chrysanthemum (Dendranthema grandiflorum L., cv. 'Cheonsu') plantlet cultured in vitro. The explants of single-node cuttings were exposed to monochromic or mixture radiation of blue, red, or green under continuous and intermittent lighting for 42 days. The intermittent lighting of 20 sec. on and off per minute significantly stimulated shoot elongation with lower number of internodes compared with continuous lighting treatments. However, continuous blue, red, or green light gave greater dry weight comparing the intermittent lighting, and the lowest weight was recorded at the continuous fluorescent lamp. Otherwise, the plantlet growth in dry weight or leaf area was inhibited by the green light controlled at 50 times intermittence but internode elongation was significantly increased. These results showed that the plantlets were successfully grown under the LED Chamber System controlled with different light qualities and lighting types. Quantitative growth of the plantlets was improved under the shorter photoperiod with a intermittent lighting cycle compared with continuous lighting using fluorescent lamps. It is concluded that the growth and development of in vitro plantlets such as single-node cuttings can be achieved by the controlling of light quality or lighting type during the photoperiod per day with a lower electric cost compared with conventional continuous lighting system.

• Atmosphere
• /
• v.27 no.4
• /
• pp.499-509
• /
• 2017

Possible links among cosmic ray, cloud, and climate have scientific uncertainties. The reputed topics have been highly controversial during several decades. A link between the atmospheric ionization by galactic cosmic rays (GCR), which is modulated by solar activities, and global cloud cover was firstly proposed in 1997. Some researchers suggested that the GCR can stimulate the formation of cloud condensation nuclei (CCN) in the atmosphere, and then the higher CCN concentrations may lead to an increase of cloud cover, resulting in a cooling of the Earth's climate, and vise versa. The CLOUD (Cosmic leaving outdoor droplets) experiment was designed to study the effect of GCR on the formation of atmospheric aerosols and clouds under precisely controlled laboratory conditions. A state-of-the-art chamber experiment has greatly advanced our scientific understanding of the aerosol formation in early stage and its nucleation processes if the GCR effect is considered or not. Many studies on the climate-GCR (or space weather) connection including the CLOUD experiment have been carried out during the several decades. Although it may not be easy to clarify the physical connection, the recent scientific approaches such as the laboratory experiments or modeling studies give some implications that the research definitively contributed to reduce the scientific uncertainties of natural and anthropogenic aerosol radiative forcing as well as to better understand the formation processes of fine particulate matters as an important parameter of air quality forecast.

• Fashion & Textile Research Journal
• /
• v.11 no.6
• /
• pp.947-952
• /
• 2009

The purpose of this study is to analyze skin wettedness($w$) used as the rate index of thermal comfort, and to evaluate the wear comfort of outdoorwear. Skin wettedness is widely used to express the degree of thermal comfort. If skin wettedness exceeds a certain threshold, the body feels damp and discomfort. An experiment which consisted of rest(30 min), exercise(30 min) and recovery(20 min) periods was administered in a climate chamber with 10 healthy male participants. Two kinds of outdoorwears made of 100% cotton fabrics (Control) and specially engineered fabrics having feature of quick sweat absorbency and high speed drying fabric (Functional) were evaluated in the experiment. The condition of climate chamber was controlled according to the thermal insulation of 4 kinds of experimental ensembles(E1~E4). Total sweat loss, sweat loss absorbed into clothing and skin temperature were measured. Skin wettedness was calculated from the ratio of evaporative rate to the maximal evaporative capacity. Skin wettedness of 'Functional' was lower than 'Control' in the 3 kinds of ensembles(E1, E2, E4) because the materials of 'Functional' were composed of quick sweat absorbency and high speed drying fabrics, water vapour permeability and waterproof fabrics.

• Fashion & Textile Research Journal
• /
• v.10 no.5
• /
• pp.683-689
• /
• 2008

The purpose of this study was to investigate physiological responses such as rectal temperature, skin temperature, micro climate, sweat rate and subjective sensations using cold protective clothing with five different clo value. The clo value was measured by thermal manikin in windless condition. Healthy five 20's males volunteered as subjects for wearing trial experiment. The climate chamber was controlled at $50^{\circ}C$, 65% RH. The experiment consisted of repeated exercise and recovery periods. We found that the higher clo value has, the higher mean skin temperature, micro climate and sweat rate show. They felt warm and wet with higher insulation clothing. Thermal comfort increased in the last recovery period after exercise. There was significant difference between five cold protective clothing. In correlation analysis of clo value, it showed that correlation coefficient(r) values were more than 0.8. Therefore, in terms of clothing insulation, we found that correlation between thermal manikin experiment and wearing trial experiment was high. Clothing insulation could be variable according to many factors such as body movement, covering area, clothing gap, layering and design. Considering the body movement, we thought that insulation measurement need to carry out both thermal manikin experiment and wearing trial experiment.

• Korean Journal of Human Ecology
• /
• v.7 no.1
• /
• pp.119-127
• /
• 1998

The purpose of this study was to evaluate thermal properties of pesticide protective clothing made of three different nonwoven fabrics which have barrier properties of pesticide. In order to assay the thermal properties of experimental clothing, thermal resistance measurements for clo value and thermographic assessment were conducted using a surface temperature controlled thermal manikin. The thermal manikin was dressed with underwear and experimental clothing. Air temperature in a climate chamber was kept at $28^{\circ}C$ and its humidity was 70% RH. Air velocity was controlled at less than 0.15m/s. Inner radient temperature was almost equal to the air temperature. The basic thermal insulation value(Icl) of underwear was 0.28 clo. The thermal properties of the experimental clothing were varied according to the type of material used in construction. The basic clothing insulation value for C1(spunbonded nonwoven fabric), C2(spunlaced nonwoven fabric), C3(SMS nonwoven fabric) were 0.705 clo, 0.725 clo, 0.738 clo respectively. The C3 experimental clothing made of SMS resulted in higher surface temperatures than the others with more yellowing spots being evident on the thermogram.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.14 no.1
• /
• pp.19-27
• /
• 2012

The open-top chamber (OTC) system is designed for long term studies on the climate change impact on the major tree species and their community in Korea. In Korea Forest Research Institute (KFRI), the modified OTC system has been operating since September 2009. The OTC facility consists of six decagon chambers (10 meters in diameter by 7 meters high) with controlled gas concentration. In each chamber, a series of vertical vent pipes are installed to disperse carbon dioxide or normal air into the center of the chamber. The OTC is equipped with remote controlled computer system in order to maintain a stable and elevated concentration of carbon dioxide in the chamber throughout the experimental period. The experiment consisted of 4 treatments: two elevated $CO_2$ levels ($1.4{\times}$ and $1.8{\times}$ ambient $CO_2$) and two controls (inside and outdoors of the OTC). Average operational rate was the lowest (94.2%) in June 2010 but increased to 98% in July 2010 and was 100% during January to December 2011. In 2010~2011, $CO_2$ concentrations inside the OTCs reached the target programmed values, and have been maintained stable in 2011. In 2011, $CO_2$ concentrations of 106%, 100% and 94% of target values has been recorded in control OTC, $1.4{\times}$ $CO_2$-enriched OTC and $1.8{\times}$ $CO_2$-enriched OTC, respectively. With all OTC chambers, the difference between outside and inside temperatures was the highest ($1.2{\sim}2.0^{\circ}C$) at 10 am to 2 pm. Temperature difference between six OTC chambers was not detected. The relative humidity inside and outside the chambers was the same, with minor variations (0~1%). The system required the highest amount of $CO_2$ for operation in June, and consumed 11.33 and 17.04 ton in June 2010 and 2011, respectively.

• Journal of the Korean Home Economics Association
• /
• v.27 no.3
• /
• pp.29-38
• /
• 1989

The purpose of this study is to investigate the physiological respones and subjective wearing sensations of the body of different materials of underwears. Experimental underwears were round neck-line shirts made of 100% cotton (60's plain stitch), 100% untreated nylon and hydrophillic finished 100% nylon (140 D. tricot). Four healthy female served as subjects. The experimental chamber was controlled at a constant temperature (23±1℃), constant relative humidity (53±3%) and air velocity of 0.25m/sec. The skin temperature, rectal temperature, pulse rate, clothing climate of temperature and humidity, and subjective wearing sensations were measured every five minutes during 75min. The results showed the level of the fiber hygroscopic properties was most relevant in the sensations of wearing: thus, cotton and treated nylon were felt by the subjects as more confortable fabrics, than untreated nylon.