• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.298-300
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• 2006

온도에 따른 건조속도의 변화는 온도가 높을수록 건조속도가 급가속화되고, 온도가 낮을수록 완만한 형태를 보임을 알 수 있었다. kW가 증가할수록 항률건조 시간이 줄어들고, 한계함수율에 도달하는 시간이 짧아지는 경향을 나타냈다.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.145-148
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• 1989

Shiitake mushrooms were dried by hot air, far infrared and freeze dryers in order to compare qualities after drying. When hot air drying was performed with the four temperature variations ranged from $45\;to\;70^{\circ}C$, there was tendency to increase volume retention but decrease rehydration ratio, as drying temperature increased. And the largest amout of 5'-GMP was contained in mushroom dried at $50^{\circ}C$. For far infrared drying, volume retentions were lower but rehydration ratios were higher, as compared with hot air drying at the same temperature. In freeze drying, freezing rate had no influence on volume retention but rehydration ratio was highest value when frozen at $-18^{\circ}C$. As shelf temperature increased(drying rate increased), rehydration ratio increased. Also, contents of 5'-AMP, 5'-GMP and 5'-XMP increased with the increase of freezing rate and drying rate.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.115-115
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• 2017

2013년 국내 시설(비닐, 유리 온실)에서 재배되는 토마토, 풋고추, 파프리카의 생산량은 총 632,315 톤으로 잎, 줄기 등 발생되는 부산물은 수확량의 약 30%에 해당되는 189,695 톤으로 추정되며 대부분 노지에 방치 유실되거나, 소각 처리된다. 본 연구에서는 이처럼 단순 폐기되는 농업폐기물을 재활용한 고형연료 제조에 필요한 건조장치를 개발하고 실험을 통해 그 성능을 확인하고자 하였다. 연구를 위해 건조용량 100 kg/hr인 실험실용 건조기를 제작하였다. 경상남도 진주시 농업기술원 온실에서 재배되는 파프리카, 토마토, 딸기, 가지, 고추 등의 부산물을 실험원료로 사용하였다. 원료성상, 원료이송방식, 송풍량, 건조온도, 건조시간에 따른 부산물 건조특성을 파악하였다. 원료를 비교적 짧게 절단하고 열풍이 배출되는 다공판위를 견인형 컨베어로 이송시키는 형태의 경우 건조실험 결과 세절된 원료에서 추출된 내부 수분이 외부로 유출되어 원료들 사이의 공극을 채워 건조공기가 원료층을 통과하지 못하게 하고, 특히 $100^{\circ}C$ 이상 고온에 노출되는 경우 원료표면에 잔류하는 유출 수분이 건조되면서 막을 형성하여 내부 원료들은 전혀 건조가 되지 못하는 현상이 관측되었다. 이러한 원료내부의 공극형성 불량으로 국부적으로 공기가 통과되는 부분만 집중적으로 급격한 건조가 진행되고 공급된 건조공기 대부분이 이 부분으로 유출되어 효과적인 건조가 전혀 진행되지 못하였다. 피건조물 사이의 공극형성을 위해 원료를 절단하지 않고 수행한 건조실험 결과 건조 풍량 및 온도에 따라 건조속도 및 처리용량이 다르게 나타나는 것을 알 수 있다. 특히 송풍량과 압력을 증가 시킨 건조 결과로 건조 상하층 간 불균일 건조 해소 및 건조속도, 건조능력에서 연구목표 치를 상회하는 결과를 보여준다. 특히 건조공기온도 $150^{\circ}C$ 이하에서 풍량을 증가시켜서 원하는 건조작업 수행이 가능함을 확인할 수 있었다.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1107-1113
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• 1998

This work was to study the potential use of germinated and microwave-vacuum-dried brown rite as a raw material for enzyme food. Brown rice was soaked in water at $15^{\circ}C$ for 2 days and then germinated at $25^{\circ}C$ for 4 days. The germin ated brown rice was then dried by different drying methods: microwave vacuum drying 1(drying only), microwave vacuum drying 2 $(drying{\rightarrow}crushing{\rightarrow}drying)$, hot air drying, vacuum drying and freeze drying. Each drier except freeze drier was set to maintain the sample temperature to be $60^{\circ}C$. During microwave vacuum drying 1 and 2 the sample reached $60^{\circ}C$ much faster (5 min) and was dried much faster (2 to 3 hrs for microwave vacuum drying 1 and 2 than the other drying methods. The initial drying rate of microwave vacuum drying was ten times faster than that of hot air drying. The microwave vacuum drying produced a dry sample of the highly retained enzymic activity, followed by freeze drying, vacuum drying and hot air drying.

• Journal of the Korean Wood Science and Technology
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• v.9 no.4
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• pp.1-21
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• 1981

Exterior grades of Douglas-fir and aspen plywood were impregnated with interior fire-retardant chemicals and redried under low-, intermediate-, and high-temperature drying conditions. Fire-retardant treatments included borax-boric acid, chromated zinc chloride, minalith, pyresote, and a commercial formulation. Drying processes included kiln and press-drying. Evaluated were drying rates and defects generated. The borax-boric acid and the commercial treatments redried at rates similar to water-treated controls. Other salt treatments were significantly slower drying and more defect prone. Chromated zinc chloride treatment was consistently the slowest drying and most defect prone. Press drying was three times faster at an equivalent temperature level. However, thickness shrinkage doubled because of 50 1b/in. platen pressure.

• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.175-184
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• 1989

Kinetics of ascorbic acid and browning that may use on the optimization of food dehydration were evaluated. Banana was chosen for this as the representative test material. We have described the destruction of ascorbic acid and browning as first and zero order reactions. The temperature dependence between two reactions were conducted with Arrhenius equation. Finally we have operated SPSS computer programs reapeatedly that we found very dose value of the parameter between result of ascorbic acid and browning. The attained Kinetic models were well prepared for the value of result experiments and the models may use on optimization for dehydration progress. Destruction rate of ascorbic acid and browning rate were low at initiation of progress, increased to show maximum at the low moisture on mid-progress and then decreased gradually. Freeze drying showed the most constant quality of product in this case.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.1-8
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• 2019

The primary purposes of this study are to understand a fundamental effects of electro-deposition on reinforcing steel in saturated Ca(OH)2 electrolyte, and evaluate the corrosion rates of rebars under cyclic 3wt.%NaCl immersion and dry corrosion environment. The three cement mortar specimens with cover thickness 5, 10 and 30mm, were prepared in the experiment. To monitor the corrosion rates of rebars in mortar, the three cement mortar specimens were exposed to 110 wet-drying cycles(8-hour-immersion in 3wt.%NaCl and 16-hour-drying in a room temperature) in the laboratory. During the wet-dry cycles, the polarization resistance, Rp, and solution resistance, Rs, were continuously measured. The instantaneous corrosion rates of rebars on the effect of electro-depositing with sat. Ca(OH)2 electrolyte were estimated from obtained R-1p and degrees of wetness were estimated from Rs values. From the experimental results, the corrosion rates of rebars were greatly accelerated by wet/dry cycles. During the mortars exposed to drying condition, the large increases in the corrosion rates were showed at all rebar surfaces in three mortar specimen, attributed from the accelerated reduction rates of dissolved oxygen in drying process. However, the corrosion rates on rebar surface electrochemically deposited with sat. Ca(OH)2 electrolyte showed the clear decreases, caused by calcium deposits in the porous rust layer.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.625-630
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• 1999

This work was to study drying characteristics of the brown rice koji, an enzymic health food, using microwave under vacuum. Cooked brown rice was inoculated with Aspergillus oryzae and incubated at $32^{\circ}C$ for 6 days. The brown rice koji was dried by different drying methods: microwave vacuum drying, hot air drying, vacuum drying and freeze drying. Each drier except freeze drier was set to maintain the sample temperature at $40^{\circ}C$. During microwave vacuum drying, the sample reached $40^{\circ}C$ much faster (within $5{\sim}10\;min$) and was dried much faster (2 hrs) than the other drying methods. The initial drying rate of microwave vacuum drying was ten times faster than that of hot air drying. The microwave vacuum drying produced a dry sample of the highly retained enzymic activity, followed by freeze drying, vacuum drying, and hot air drying.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.369-374
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• 2002

최고급 품질의 홍삼제조를 위한 공정을 개발하고자 건조기를 제작하였다. 건조기는 온도, 습도의 계측이 가능하고 이를 컴퓨터와 연결하여 사용자가 원하는 온도, 습도로의 제어가 가능하도록 설계하열다. 건조기의 작업용량은 1회에 원료수삼 30지가 처리되도록 설계되었다. 이를 위한 건조챔버의 크기는 6년근 1등급 수삼의 크기를 고려하여 700$\times$700$\times$1500mm로 결정하였고 건조과정중의 수삼의 상태변화를 알기 위하여 건조챔버 전면에 유리를 설치하여 육안 관찰 및 영상처리장치에 의한 모니터링이 가능하도록 하였다. 수삼의 균일한 건조를 도모하기 위하여 대나무 채반을 속도조절이 가능한 모터와 체인을 이용하여 챔버 내에 서 0~10rpm의 속도로 회전되도록 설계하였다. 그리고 건조시 챔버 내의 공기상태 계측 및 제어용 프로그램을 개발하였다. 제작된 홍삼제조용 건조기의 성능 평가결과 설정된 온도와 습도를 정밀하게 계측제어 할수 있었으며, 원하는 건조수준을 유지는데 성공했다. 건조기 내부에서의 온도 분포와 풍속분포를 SAS통계 package GLM을 이용하여 유의수준 5%의 범위에서 Student T~test를 한결과, 계측지점간의 유의 차가 없어 온도와 풍속의 분포가 균일한 것으로 나타났다.

• Magazine of the Korea Concrete Institute
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• v.8 no.1
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• pp.111-120
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• 1996

Drying shrinkage is a very important properties of concrete, which is affected by environmental conditions. The environmental conditions are temperature, relative humidity, and wind speed, which is quite variable and its effct on drying shrinkage is quite complex, too. In this study, environmental effects on drying shrinkage wrer integrated into one variable-evaporation rate. In several different environmental conditions, evaporation rate was measured with Evaporometer and compared with PCA chart, and also compared with measured drying shirnkage to verify the possibility of being a single parameter. The results are summarized in a prediction chart and prediction equation for drying shrinkage.