• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.469-477
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• 2003

삼림에서 벌채된 목재는 대부분 건조공정을 거쳐 산업용 재료가 되므로 건조정도에 따라 목질 재료의 품질이 결정된다. 목재에 포함된 과도한 수분을 제거하여 운송비용을 줄일 수 있으며 목재를 적절하게 건조하게 되면 목재 사용 중에 발생할 수 있는 수축 및 팽윤을 제한할 수 있을 뿐만 아니라 건조과정을 통해 비틀림, 갈라짐, 할열 등과 같은 결함의 발생을 크게 줄일 수 있다. 또한 건조된 목재는 생재에 비해 기계 가공이 보다 용이하기 때문에 정확한 치수로 재단이 가능하며, 각각의 부품으로 재단한 부재를 못이나 나사못, 볼트, 접착제 등을 사용하여 견고하게 짜 맞출 수 있다. 그리고 도장성능이 향상되어 기능성을 증진시킬 수 있으며, 건조 후의 방부처리를 통해 장기간의 사용이 가능하다. (중략)

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1242-1248
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• 2013

This study was performed to determine the effects of pretreatment (NT: non-treatment, BTS: boiling treatment with 3% sodium chloride, DTG: dipping treatment in glycerol) and drying methods (sun drying, hot air drying, and cold air drying) on the physicochemical properties and antioxidant activities of dried jujube (Zizyphus jujuba Mill.) fruits. Our results show that moisture content is lower (P<0.05) with DTG, and that moisture content is lower with hot air drying compared to other drying methods. The bulk density was highest with BTS. The soluble solids content was highest with DTG. Additionally, the soluble solids content were highest in the following order: hot air drying> cold air drying> sun drying. The titratable acidity of hot air drying was highest of all the drying methods. The titratable acidity was higher with NT and DTG, and the brix and acid ratio of sun drying was higher than other drying methods. Among the drying methods, BTS showed the best browning-retarding effect, whereas boiling treatment affected quality and color. The total polyphenol content from hot air drying and NT or DTG treatment was relatively higher than the content from BTS. The flavonoid content was highest with BTS, and all dried jujube showed relatively high antioxidant activities. The sensory evaluation results indicated that the organoleptic scores for overall preference were higher in the NT and DTG treatment groups. These results suggest that pretreatment and drying methods affect the quality of dried jujube fruit, and show that glycerol treatment with hot air drying can be applied to the production of high quality dried jujube.

• Food Science and Preservation
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• v.24 no.5
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• pp.658-665
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• 2017

The current study was performed to investigate the changes of bio-activities of Salicornia europaea (SE) depending on the different dry methods. The ethanol extracts were prepared from the freeze-drying SE (FD), hot-air drying SE (HD), and shade drying SE (SD). Their anti-oxidant and anti-thrombosis activities were compared. The yields of ethanol extraction in FD, HD, and SD were 14.4, 13.2 and 11.9%, respectively. The highest contents of total polyphenol (4.6 mg/g) and total sugar (23.4 mg/g) were shown in FD, whereas, the highest content of reducing sugar (14.6 mg/g) was observed in HD. In anti-oxidation activity assay, the FD and HD showed similar radical scavenging activities and reducing power. However, in SD, nitrite scavenging activity and reducing power were severely decreased. In anti-coagulation activity assay, the thrombin time (TT), prothrombin time (PT) and activated partial thromboplastin time (aPTT) of FD, HD and SD did not show significant changes at 5 mg/mL concentration. But the HD at 7 mg/mL had strong inhibitions against thrombin and blood coagulation factors. The platelet aggregation and hemolysis activities were not affected by dry methods. Our results suggest that both FD and HD are effective to maintain the functional ingredient of SE, and HD is economic and efficient dry process for production of functional food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1353-1358
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• 2010

Improvement in the utilization of grape pomace, antioxidant activities and antioxidant compounds of grape pomace was analyzed to clarify the influence of drying method such as $80^{\circ}C$ hot air and freeze ($-70^{\circ}C$) drying process. For proximate composition, crude protein and fat contents of hot air drying sample were higher than freeze drying sample. The lightness and redness values of freeze drying sample were higher than hot air drying sample, but yellowness of hot air drying sample was higher. The contents of total polyphenols and anthocyanins were higher in freeze drying sample. DPPH radical scavenging activity and ABTS scavenging activity of freeze drying sample were higher than hot air drying sample. The reducing power and FRAP value of hot air drying sample was higher than freeze drying sample. The result indicated that freeze drying method is slightly better than hot air drying method for antioxidant compounds and antioxidant activity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.67-74
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• 2001

A field experiment was carried out to determine the effects of chemical/mechanical treatments at mowing on the field drying rate and hay quality of alfalfa(Medicago sativa L., cv. Vernal) and spring oats(Avena satvia L., cv. Swan). The chemical drying agent of 2% $K_2CO_3$, mechanical mower conditioning, and no treatment(control) were treated for hastening hay-making in the spring of 1997. The forages were harvested at early bloom stage in alfalfa and heading stage in oats. After field dry, square bales were made by hay baler, and the dry matter(DM) loss, visual estimation and nutritive value of hay were evaluated after storing two months. The field drying rates of alfalfa and oats were high at mechanical treatment, but the drying effectiveness of chemical agents alone was very low. With mower conditioning, the duration of field dry was shortened by 1 day compared with control. therefore, mower conditioning enhance the field drying rate of alfalfa and oats. The DM loss of alfalfa and oats hay was reduced by mechanical treatment, but the efficiency by chemical alone was low. The visual score(leafiness, green color, odor and softness) of hay at mechanical treatment was slightly higher than that of chemical and control. The nutritive value(ADF, NDF, in vitro digestibility, and relative feed value) of hay was also high with treatment of mechanical, but those of chemical alone were similar compared with control. The nutritive value of hay after two months in both alfalfa and oats was decreased when compared with at harvest.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.428-439
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• 1992

Drying process in a fixed bed red pepper dryer was modeled and simulated. Drying efficiency describing the effectiveness of energy usage in red pepper drying was defined as a ratio of energy used for moisture evaporation to total energy consumption, and expressed in combination of measurable temperature variables. The efficiency was compared with real evaporative efficiency and tested in the simulated and experimental drying. An overall drying efficiency was derived, and analyzed for various control variables consisting of drying temperature, air recycle ratio and air flow rate. Optimal operation conditions of drying was then searched by Box's complex method by using it as an objective function. Carotenoids retention was simulated and put as a constraint of product quality in the optimization. The optimization results gave that two staged drying operation could improve the ding efficiency compared with single staged drying. As a technique for further energy saving automatic termination of drying appeared feasible by monitoring an exit air temperature from dryer.

• Magazine of the Korea Concrete Institute
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• v.9 no.6
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• pp.217-223
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• 1997

재생콘크리트의 압축강도와 휨강도는 재생골재의 혼입량이 증가할수록 감소하였으며 플라이애쉬를 혼화재로 사용할 때 그 양이 증가할수록 재생콘크리트의 조기 압축강도는 떨어졌다. 골재원에 따른 압축강도는 재생골재의 혼입량이 적을수록, 양생기간이 길어질수록 증가하엿으나, 전반적으로 비슷한 강도변화의 경향을 보여주고 있다. 재생콘크리트의 휨강도 발현은 보통 콘크리트와 비슷하나, 휨강도에 대한 압축강도비는 보통 콘크리트에 비하여 낮았다. 재생콘크리트의 건조수축은 재생골재의 혼입량이 증가할수록 증가하였으며 , 특히 재령2주와3주사이에 건조수축량이 보통 콘크리트에 비해 월등히 높았다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.198-203
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• 2006

This study was conducted to select the temperature for hot air drying method, cutting method, and solution that inhibits enzymatic browning in making high quality powder from sweetpotato roots. It was observed that $70^{\circ}C$ was the best temperature for air drying method wherein the dry matter rating, dry matter time, flour yield and chemical component were considered. The proper cutting thickness should be 2.0 mm considering the vitamin C content and sensory evaluation of sweetpotato flour. Also, 1% vitamin C solution inhibited enzymatic browning of sweetpotato.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.87-93
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• 2006

To evaluate the deformational characteristics of subgrade soils, four subgrade samples in Korea were tested using the RC and TS tests with various dry unit weight and water content. Both the maximum modulus and normalized modulus reduction curves of subgrade soils were affected by the dry unit weight. The normalized modulus was decreased about 20% with increasing of relative compaction of 5%. It was founded that the variations of modulus of subgrade soils in Korea were over 40% with water content variation of $\pm$2%, and those effects can be estimated by exponential model. However, the normalized modulus reduction curves were almost identical and independent of water content. It was also founded that confining pressure, loading frequency, dry unit weight, and water content have an affect on modulus of subgrade soils independently. Therefore, it can be considered that those effects are independent variables.

• Journal of Energy Engineering
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• v.7 no.2
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• pp.180-186
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• 1998

In this study, the effect of shear rate on the viscosity variation is examined to understand the flow characteristics of the mixture of bentonite and water. The variation of film thickness according to mixing ratio and viscosity is measured to characterize the film formation. And, the separation of dried film is studied according to film thickness. Specific surface area affecting on adsorption capability is measured using BET method. The viscosity decreases and the film thickness increases as the mixing ratio increases. The separation characteristic of dried film is suitable within a range of 40 to 150 ${\mu}{\textrm}{m}$ in film thickness and 5 to 10% in mixing ratio.