• Journal of Biosystems Engineering
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• v.25 no.3
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• pp.227-232
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• 2000

A natural air in-bin grain dryer with a grain circulator was developed for on farm use. Natural air drying test for rough rice was carried out to evaluate drying rate, uniformity of moisture content distribution in grain bed and energy consumption. It took 10 days to dry 8 ton of paddy rice from 21.9%(w.b) of moisture contents to 16.7%(w.b), by prototype dryer and the average drying rate was 0.52%/day. The uniformity of moisture content after drying was superior to a conventional natural air dryer in which grains were not mixed during drying periods. The dryer performance evaluation index was 738.3kJ/(kg.water), which was more effective than that of grain circulation type hot air dryer(3,500∼5,000 kJ/kg.water)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.13-18
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• 1978

The present study was conducted to elucidate the pattern in changes of trimethylamine oxide and related compounds in the muscle of Alaska pollack during drying, especially referred to formaladehyde and dimethylamine. Three kinds of dried samples of Alaska pollack, sun dried, hot-air dried, and salted-sun dried, were prepared and analyzed for their contents of trimethylamine oxide, trimethylamine, dimethylamine, and formaldehyde. The amount of trimethylamine oxide remained in the salted-sun dried sample was relatively higher than those in the other two samples. In the content of trimethylamine, the hot-air dried sample showed an exceedingly high value shelving forty-two times higher than the raw sample while the other two samples showed barely three to four times content based on the raw sample. The dimethylamine content in the hot-air fried sample was comparatively lower than those in the other two samples, the former marked about ten folds of the raw sample's and tile latter showed about fifteen folds, respectively. Refering to the content of formaldehyde, it decreased to eighty-three percent of initial content in the hot-air dried sample. On the contrary, it increased about two times initial content in the other two samples, respectively. As a tendency, the formaldehyde content appeared increased or decreased correlatively with the dimethylamine content, whereas the case was reverse for the trimethylamine content.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.741-750
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• 2004

Air voids in hardened concrete have an important influence on concrete durability such as freeze-thaw resistance, surface scaling resistance, and water permeability, and they have been characterized by spacing factor Linear traverse and point count methods in ASTM standard have been used in estimating an air void system in hardened concrete. However, these methods require lots of time and efforts, further they are not repeatable. Image analysis method could be utilized In estimating an air void systems in hardened concrete with a developments of microscope, digital camera and computer program. The purpose of this study was to develope image analysis method and provide a guideline by comparing the results from ASTM method and image analysis method. The concerns were at air void content and diameter distribution, air voids system as well as spacing factors. The experimental variables included air content by air entrained agent (0, 0.01, $0.03\%$) and depth of specimen (top, middle, bottom). The result showed that it was possible to calculate spacing factor using image analysis technique, as well as air content, air diameter distribution, and air structure. This study also contributed in developing an reasonable and repeatable image analysis method.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.2
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• pp.136-141
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• 2000

This study was conducted to analyze the properties of the roasted dandelion tea prepared after various pre-treatments such as pre-drying, steaming and air blast drying. The dandelion tea was prepared by roasting the pre-treated dandelion leaves and its total yield, pH, soluble solid content, turbidity, browning and sensory value were evaluated. Total yield and soluble solid content were the highest in case of air blast drying. Turbidity and browning degree were similar in all the teas regardless of their pre-treatment including pre-drying, steaming or air blast drying. The best palatability in the sensory evaluation was obtained at the steaming condition for 60 sec without pre-drying. Longer air blast drying time resulted in the increase in the a and b values. turbidity, browning degree, total yield and soluble solid content in the air blast dried tea.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.27-31
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• 2003

This paper presents the results of air-drying processes and mositure content (MC) distribution of red pine (P. densiflora) and Japanese larch (L. leptolepis) square timber with 14 cm and 16.5 cm of face size, respectively. The air-drying rates of square timber were comparatively high during the first 8 weeks, after that gradually decreased. The time to air dry square timber from initial MC to specified MC of 18 percent required about 26 weeks for 14.0 cm and 32 weeks for 16.5 cm square of red pine, and 32 weeks for 14.0 cm and 48 weeks for 16.5 cm square of Japanese larch. The longitudinal- and transverse MC distribution of these air-dried squares showed slight moisture gradient. The effect of face size on moisture gradient of Japanese larch square was more pronounced comparing with red pine one.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.109-122
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• 2022

Currently, most of the pig manure generated from pig farms in Korea is in the form of a slurry with a moisture content of about 97%. Pig manure slurry is a mixture of pig manure and cleaning water in the pig house. In this study, changes in properties of pig manure liquid fertilizer according to whether air was supplied or not and with the passage of storage period were analyzed for 120 days. During the experimental period, the degree of maturity of the pig manure liquid fertilizer was higher in the experimental closed batch reactors supplied with air than in the same type reactors not supplied with air. As the liquid fertilizer storage period elapsed, there was a tendency that liquid fertilizer was converted to a state of complete maturity. In the batch reactor in which air was supplied, the moisture content of pig manure slurry, which had a moisture content of 97.90%, was reduced to 96.82% at the end of the experiment. On the other hand, the moisture content in the reactor without air was reduced to 97.33%. The pH of the liquid fertilizer, which was 8.82 at the start of the experiment, changed to 7.57 in the reactor with air supplied and 8.75 in the reactor without air at the completion of the experiment. The nitrogen content in the liquid fertilizer was 0.198 mg/L on average at the start of the experiment and it was lowered to 0.076 mg/L in the air supplied reactor at the end of the experiment. On the other hand, the nitrogen content of the liquid fertilizer was lowered to 0.121 mg/L in the reactor to which air was not supplied. The phosphoric acid (P₂O₅) concentration in the liquid decreased higher in the liquid fertilizer filled in the reactor without air than the liquid fertilizer filled in the reactor with air supplied as the storage period elapsed. Considering the experimental results, it is considered that the quality of pig manure liquid fertilizer is improved when air is supplied to pig manure slurry and the storage period of pig manure slurry is longer.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.3
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• pp.225-232
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• 2002

The purpose of this study is to find the mechanical properties of lightweight concrete using expanded clay. Thus, slump, air content, compressive strength, elastic modulus, tensile strength, length change ratio, unitweight change ratio and absorption of lightweight concrete have been investigated. The conclusions of this study are as follows ; 1. The loss of slump and air content of concrete increased as the expanded clay content increased and the size of coarse aggregate decreased. 2. The compressive strength of concrete using 100% expanded clay of 13, 19mm size at 28 days were respectively 282, $252kgf/cm^2$. 3. The elastic modulus and tensile strength of concrete decreased with increase of expanded clay content. 4. The length change ratio of concrete increased with the larger coarse aggregate size, and decreased with the increase of expanded clay content. 5. The unit weight of concrete decreased with the increase of expanded clay content, and the ratio of that was larger at the early age.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.423-432
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• 1993

The changes of quality of Fresh Shiitake (Lentinus edodes) was studied in this research work by investigating the effect of low $O_2$ content and high $CO_2$ content, well known as CA Treatment in storage, on the respiration rate and PPO Activity that was the main factor in Shiitake quality decay. CA Condition was conducted in 3 research periods that combined the $O_2$content(1%, 5% and 10%) and $CO_2$ content (5%, 10%, 15% and 20%) and air treatment as the control. The lower $O_2$content was the lower respiration rte that was showed in combination the lower respiration rate that was showed in combination of 20% $CO_2$ and 1% $O_2$ (the lowest), and the control air treatment was the highest . Very low $O_2$ content, conversly, did not show a satisfying result to the product.

• Food Science and Preservation
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• v.23 no.7
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• pp.1018-1025
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• 2016

To investigate biological activities in Aronia melanocarpa various drying methods were employed such as vacuum freeze drying, hot air drying and cold air drying. DPPH radical scavenging activity and ABTS radical scavenging activity of vacuum freeze dried Aronia melanocarpa was higher than hot and cold air dried Aronia melanocarpa. Vacuum freeze drying method showed the greatest contents of total phenol (15.34 g GAE/100 g), flavonoid (3.10 g GE/100 g) and tannin (2.46 g TE/100 g). Total anthocyanin content decreased to 163.52 mg C3G/100 g and 50.15 mg C3G/100 g for hot and cold air drying, respectively. Vacuum freeze-dried method increased the total anthocyanin content (743.09 mg C3G/100 g) when compared with fresh Aronia melanocarpa (163.52 mg C3G/100 g). Total proanthocyanidin content of vacuum freeze dried Aronia melanocarpa has increased to 6.21 g CE/100 g more than eight times compared with fresh Aronia melanocarpa (0.71 g CE/100 g). Chlorogenic acid and neochlorogenic acid content of vacuum freeze dried Aronia melanocarpa were higher than hot air dried and cold air dried Aronia melanocarpa, increasing about three times compared with fresh Aronia melanocarpa. These results suggested that vacuum freeze drying is optimal drying method to enhance biological activities in Aronia melanocarpa.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.20-26
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• 2016

This study investigated noise characteristics of air cleaners and humidifiers in terms of frequency domains and measurement directions. Noise levels of 31 air cleaners and 36 humidifiers were measured in an anechoic chamber according to the related group standards. As for air cleaners, 5 receiving points of 1 m off from front, rear, left, right and top surfaces of the product were considered. In case of humidifiers, 4 receiving points without the rear position were considered in the same manner as air cleaners. In each case, A-weighted equivalent continuous sound level was measured three times for 1 min. As a results, most of the measured air cleaners and humidifiers showed the highest noise levels at top directions due to the air ventilating location. In case of air cleaners, averaged noise levels of top and rear positions were 49.9 and 48.2 dB(A), respectively, whereas averaged noise level of other positions was all 45.2 dB(A). In case of humidifiers, averaged noise level of top position was 44.1 dB(A) whereas averaged noise levels of other positions were 38.7 to 39.1 dB(A). In addition, high frequency content of 1 kHz and 3.15 kHz to 4 kHz for air cleaners and middle frequency content of 500 Hz to 1.6 kHz for humidifiers showed significant contribution to determination of overall noise levels with correlation coefficient of 0.9 and above.