• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.34-42
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• 1998

Three hardwood (ash, alder and black locust) and three softwood (Japanese red pine, radiata pine and Western hemlock) specimens were dried in microwave(MlW) oven and their drying rates were obtained. Their specific permeabilities were also measured by using a modified liquid permeability measuring device. The correlation between the M/W drying rates and permeabilities of six species were statistically analyzed. It was revealed that within a species there is a logarithmic relationship between the M/W drying rates and average moisture contents and that among species there is a linear relationship between the M/W maximum drying rates and the average specific permeabilities. A exception was Western hemlock, which was of low permeability and of high drying rate. A Me-time equation, which showed a good agreement with the actual data, was derived. Thus using this equation the moisture contents of wood and the drying end points of M/W drying could be predicted. Infrared images of the thermal distribution in wood were illustrated.

• Journal of Biosystems Engineering
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• 제25권2호
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• pp.89-96
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• 2000

In this study, experiments were performed for various drying air temperatures, air flow rates tray distance to analyze drying characteristics of batch type tunnel dryer. In comparison of tunnel drying with cabinet drying which is currently used in the farm, the results of drying simulation model of cabinet dryer was used and then the possibility of applying the drying simulation model of cabinet dryer to batch type tunnel dryer was investigated. The results showed that as the drying temperature increased, the drying rte and moisture difference in the direction of air flow increased and as the air flow rate increased, the drying rate increased and moisture differences decreased. In tunnel dryer, drying through bottom of the tray had large effect on drying rate and the effect was more significant when the drying temperature increased. As air flow rate increased, the difference of drying rates between tunnel and cabinet drying increased and drying rate of tunnel of drying was higher. The drying simulation model could estimate moisture content in tunnel more precisely by using modified effective moisture diffusion coefficient for air flow rate.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1993년도 학술대회지
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• pp.155-163
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• 1993

An American ginseng(Panax quillquefolium L) industry has emerged in British Columbia, Canada over the past ten years. Interest has grown very rapidly and with this development, attention is now moving away from field production issues and emphasis is being directed to enhancements in ginseng storage, drying and processing. There is a dearth of knowledge on these aspects even though they are crucial to international competitiveness. Enhancement dicatates the application of a systems approach to optimizing the harvest and post - harvest production system(crop digging, pre - washing cold storage. washing, drying and post - drying storage). Research in British Columbia to date has focussed on drying and storage issues and has resulted in the design of an enhanced commercial drying system. The role of dryer management, loading rates, airflow rates and pre - drying cold storage on American ginseng root drying rates and root quality were examined. From the dryer management experiments, there are distinct advantages to size sorting root to yield optimum drying rates. If unsorted root is used, efficiency is increased if the trays are systematically rotated. Loading rate experiments illustrate that increasing rates above those currently used in commercial dryers are possible without any sacrifice in quality. This has significant implications for commercial drying. Pre - drying cold storage is a most significant tool for managing drying operations. Over a period of six weeks, no discernable decrease in quality was found as a consequence of cold storage. Further, the moisture loss and the associated root surface changes(loss of surface soil in storage for example) provide new challenges for root quality management. Continued research and technological innovation will be crucial in addressing the demanding challenges of the future.

• 한국산림과학회지
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• 제87권4호
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• pp.577-583
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• 1998

우리 전통 악기용 밤나무와 오동나무 향판용재를 여름 초순부터 잔적하여 70일간 옥외 천연건조와 150일간 옥내 천연건조하여 함수율, 건조속도 및 건조시간을 비교하였다. 밤나무 판재의 평균 최종함수율과 건조속도는 옥외천연건조의 경우 각각 20.6%와 0.78%/일(日)이었고, 옥내 천연건조의 경우 각각 16.6%와 0.44%/일(日)이었다. 오동나무 판재의 평균 최종함수율과 건조속도는 옥외 천연건조의 경우 각각 16.7% 와 1.53%/일(日)이었고, 옥내 천연건조의 경우 각각 13.5%와 0.77%/일(日)이었다. 이들 수종의 옥외 평균 천연건조속도는 옥내 경우보다 2배 정도 더 컸었는데 섬유포화점(30%) 이상에서 매우 컸었으며 감율건조하다가, 섬유포화점 이하에서는 불규칙하게 감소하였다. 그러나 옥내 천연건조속도는 밤나무의 경우 함수율 55% 이상, 그리고 오동나무의 경우는 함수율 80% 이상에서 컸었으며 감율건조하다가, 이들 함수율 이하부터 불규칙하게 감소하였다.

• Journal of the Korean Wood Science and Technology
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• 제25권4호
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• pp.51-60
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• 1997

We investigated the characteristics of air-and vacuum-drying heated by hot plates for 8~14cm-diameter logs or 6~12cm-thick pillars of Pinus koraiensis. And we evaluated the effects of longitudinal kerf and vacuum drying heated by hot plates. The vacuum drying times from green to 10.9~18.6% MC were 15 days, and these times were one-fifth compared to the air-drying times. The longitudinal kerfing had no significant, effect on drying rates during both air-drying and vacuum drying. But drying defects such as surface checks and V-shaped cracks were effectively prevented during air-drying and vacuum drying by longitudinal kerfing. The vacuum drying was more advantageous than air-drying for preventing of surface checks, end checks and V-shaped cracks, and especially, the vacuum dried pillars with longitudinal kerf were almost free from drying defects. In accelerated weathering conditions the resin did not exude for all specimens.

• Journal of the Korean Wood Science and Technology
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• 제35권5호
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• pp.1-6
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• 2007

Boiling-in-oil process was performed to investigate the high-temperature drying characteristics of 25, 50, and 70 mm-thick flat-sawn Douglas-fir lumber. Drying rates, moisture profiles and temperature profiles were monitored. Fully refined paraffin wax was used as drying agent and heated to $130^{\circ}C$. Average drying rates of 25, 50, and 70 mm-thick specimen were 11.6, 6.7, 5.0%/h, respectively. The moisture content differences between cores and ends were 1~2% in 25 mm-thick and 200 mm-long sample and over 10% in 50 mm-thick and 600 mm-long sample.

• 한국식품과학회지
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• 제38권5호
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• pp.635-641
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• 2006

본 연구에서는 자연건조 및 온풍건조에서의 문제점을 보완하고자 냉풍건조공정을 이용하여 말린 오징어의 품질 특성을 비교 하였다. 건조속도는 온풍건조가 15시간만에 목적하는 수분함량에 도달하여 가장 단시간에 건조가 완료되었으며 자연건조, 냉풍건조 순이었는데 $7^{\circ}C$ 냉풍건조가 건조시간이 165시간으로 가장 많이 소요되었다. 건조방법과 건조온도에 따른 ${\Delta}E$ 값은 자연건조가 57.78로 색의 변화가 가장 컸으며, 물성은 냉풍건조가 다른 간조방법에 비해 조직감이 우수하였다. TBA 가는 건조시간 및 온도가 증가할수록 높아지는 경향이었고 총아미노산 및 지방산 함량은 냉풍건조 $15^{\circ}C$가 다른 건조방법에 비해 우수하였다. 콜레스테롤 함량은 온풍건조 $30^{\circ}C$에서 488.5 mg/100 g으로 가장 많이 감소하여 건조조건이 마른오징어의 콜레스테롤 함량에 많은 영향을 끼침을 확인하였다. 종합적인 기호도는 지질의 산화에 의한 향미 변화와 갈변의 발생정도가 낮은 $15^{\circ}C$ 냉풍건조가 가장 우수하였다.

• Journal of the Korean Wood Science and Technology
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• 제19권2호
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• pp.30-39
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• 1991

Internal moisture gradients of 3cm-thick radiata pine (Pinus radiata) sapwood and meranti(Shorea spp.) heartwood were determined by using slicing method during drying and were predicted by Hart's Sorption Simulation. The shapes of internal moisture gradients. moisture contents and drying rates, which were obtained by the slicing method. were compared with those predicted by Sorption Simulation. After the 2nd fitting attempts. the differences between the gravimetric drying rates and the drying rates predicted by Sorption Simulation were less than 0.021%/hr for radiata pine and 0.043%/hr for meranti. The shapes of the internal moisture gradients predicted by Sorption Simulation were in good agreement with those obtained by the slicing method. It could be concluded that Sorption Simulation be an excellent tool to predict internal moisture gradients of wood.

• 한국식품저장유통학회지
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• 제8권2호
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• pp.140-145
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• 2001

Although the drying times of paddies were significantly shortened by the application of higher drying temperatures, the 12, 10 and 8 hours were needed for the reduction of moisture contents from 23.55 to 15% at the temperatures of 45, 50 and 55$\^{C}$, respectively. Milling yields(MY) and rice rates(HRR) were decreased by increasing of the drying temperature. The MY ratios were 75.50, 75.42 and 75.31% and HRR were 93.28, 92.14 and 91.12% in drying temperature of 40, 50 and 55$\^{C}$, respectively. In the milling processes of tough rice with the used of a milling machine equipped with both of abrasive and friction types in a body, the reduction rates of bran and the occurrence of broken rice increased with the pressures at outlet or the recycled passing tines. In the process for humidified friction whitening of rice, it was found that the optimum addition rate of water for the best quality was the 11.2 liters per tone of white rice.

• Food Science and Biotechnology
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• 제14권5호
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• pp.661-666
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• 2005

The specific objectives of this study were to dry yam chips using microwave vacuum drying, freeze drying and hot air drying, then to coat the dried yam chips with ascorbic acid cocrystallized sucrose, and finally to compare the quality of yam chip snack foods with respect to drying and coating characteristics. The microwave vacuum dried sample showed the highest drying rates and much less surface damage than the hot air dried one did. The shape and color of the microwave vacuum dried/coated sample were allocated between those of the freeze dried/coated sample and the hot air dried/coated sample. The freeze dried/coated sample scored excessively low in organoleptic hardness and chewiness to be suitable as a snack. The hot air dried/coated sample was too deep in color, wrinkled, excessively high in organoleptic hardness and chewiness, and excessively low in mouthfeeling. Therefore, the microwave vacuum dried/coated sample presented the best overall attributes as a snack, with respect to organoleptic characteristics, shape, color, and drying rates.