• Journal of Biosystems Engineering
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• 제41권1호
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• pp.34-42
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• 2016

Purpose: This study was performed to improve the drying quality and drying rate of ginseng slices by combining microwave and far-infrared drying techniques. Methods: Based on single-factor experiments and analyses, a quadratic regression orthogonal rotation combination design was adopted to study the effects of the moisture content at the conversion point between the microwave and far-infrared techniques, the ginseng slice thickness and the far-infrared drying temperature on the chip drying time, the surface color difference value, the nutritional composition and the surface shrinkage rate index. Results: Compared to the far-infrared drying alone, the combined microwave and far-infrared drying resulted in an increase in the saponin content of the ginseng slices and reductions in the drying time, surface color difference, and shrinkage rate. Conclusions: We established a mathematical model of the relationships between the surface shrinkage rate index and the experimental factors using the multi-objective nonlinear optimization method to determine the optimal parameter combination, which was confirmed to be the following: microwave and far-infrared moisture contents of 65%, a ginseng slice thickness of 1 mm, and a far-infrared drying temperature of $54^{\circ}C$.

• 공업화학
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• 제33권2호
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• pp.145-150
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• 2022

Microalgae are attracting attention as a resource for the production of biofuels, food nutrients, biochemicals, and bioplastics. Among a wide range of sources of the biomass, microalgae have been highlighted due to relatively easy cultivation, ability to eliminate carbon dioxide, and low culturing cost. Despite the great potential of microalgal biomass as a biological material, the complexity and relatively expensive downstream processes have inhibited the commercial use of microalgae. In this study, we reviewed recent techniques for microalgal drying for the production of microalgal based products. As drying processes comprise the largest portion of microalgae processing cost, an efficient drying technique is key to the utilization of microalgal biomass.

• Journal of the Korean Wood Science and Technology
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• 제2권1호
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• pp.3-18
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• 1974

The exports of plywood are increasing annually and it has ranked first in the world market because of the high quality product and manufactured using mordern techniques. However, it is known that the exports of the other wood products, except plywood, is inactive because of their low quality. Accordingly, to increase the exports of various wood products investigations were carried out on kiln drying techniques to improve the quality of the wood. Wet wood should be kiln dried before use to prevent various drying defects such as distortion, shrinkage etc., which would develop after processing,:and also wet wood is not suitable for cutting, gluing and finishing. Therefore, the kiln drying properties of lumber from such species as oak, ramin and meranti which are used in large quantity for manufacturing exporting wood products have been studied. The results of the research are summarized as follows. (1) The end checks and the time for drying from initial moisture content of about 40 percent to 5 percent moisture content in ovendry were investigated as follows: (2) The kiln dried results, for 30mm stock, which are presented by using kiln schedule table 3 are as follows: (3) The kiln schedules for ramin, meranti and oak are given respectively as follows: Ramin kiln schedule: Table 17 and Table 18. Meranti schedule : Table 12. Oak schedule : Table 15.

• Archives of Pharmacal Research
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• 제29권10호
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• pp.921-927
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• 2006

Prolonged release micro particles of clarithromycin (CL) were prepared using Eudragit RL 100 and RS 100 by spray-drying and casting-drying techniques. For the characterization of those microparticles, preparation yield, particle size distribution, X-ray diffraction, thermal behavior, active agent content and in vitro dissolution from the microparticles were performed. HPLC was used for the assay of clarithromycin and the assay method was validated. All the formulations obtained showed prolonged release when compared to pure clarithromycin. Microparticles prepared by spray-drying method had a slower release compared to those of casting drying method. Spray-drying method seems to be a more suitable method to prepare microparticles for prolongation in release.

• 한국토양비료학회지
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• 제16권2호
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• pp.168-178
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• 1983

각기 다른 강우량(降雨量) 조건하에서 발달하여 무정형(無晶型) 광물함량(鑛物含量)이 다른 3종(種)의 하와이 화산회 토양과 4종류(種類)의 합성광물(合成鑛物)을 이용(利用)하여 4종류(種類)의 건조방법(乾燥方法)의 적용(適用)에 따른 수분함량(水分含量) 차이(差異) 및 구조(溝造)에 미치는 영향(影響)에 대하여 조사(調査)한 결과(結果)는 다음과 같다. $105^{\circ}C$ 건조기(乾燥器) 건조법(乾燥法)이 기타 $P_2O_5$ 건조(乾燥) 냉동건조(冷凍乾燥) 및 임계점(臨界点) 건조방법(乾燥方法)에 비(比)하여 수분제거량(水分除去量)이 가장 많았으며 특히 $P_2O_5$ 건조법(乾燥法)과의 차이(差異)는 토양중의 무정형(無晶型) 광물함량(鑛物含量)과 정(正)의 상관을 보여 Kaiwiki 토양 > Hilo 토양 > Kawihae 토양의 순(順)으로 켰다. 이는 $105^{\circ}C$ 가온건조(加溫乾燥)가 무정형(無晶型) 광물(鑛物)의 내외(內外)에 특별(特別)한 형태(形態)로 광물(鑛物)과 결합보유(結合保有)된 수분(水分)을 제거(除去)하는 효과(效果)가 큰 것으로 추측(推測)된다. 현미경(顯微鏡) 사진(寫眞)을 통하여 건조방법(乾燥方法)에 따른 토양 및 합성광물(合成鑛物)의 구조변화(構造變化)를 관찰하였던 바 건조기(乾燥器) 건조(乾燥) 및 $P_2O_5$ 건조(乾燥)에 의(依)하여는 공극량이 적고 조밀(稠密)하게 수축(收縮)된 대형(大形)의 단립(單粒)을 형성(形成)하였고 냉동건조(冷凍乾燥) 및 임계점(臨界点) 건조(乾燥)는 최소한(最少限)의 수축에 의하여 해면상의 구조(構造)를 유지하는 원래의 공극량에 가까운 건조전(乾燥前) 토양에 유사한 구조(構造)를 유지하였으며 임계점(臨界点) 건조(乾燥)가 한층 더 건조전(乾燥前) 토양구조에 유사하였다.

• Steel and Composite Structures
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• 제49권3호
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• pp.337-348
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• 2023

Successive wetting and drying cycles of concrete due to weather changes can endanger the safety of engineering structures over time. Considering wetting and drying cycles in concrete tests can lead to a more correct and reliable design of engineering structures. This study aims to provide a model that can be used to estimate the resistance properties of concrete under different wetting and drying cycles. Complex sample preparation methods, the necessity for highly accurate and sensitive instruments, early sample failure, and brittle samples all contribute to the difficulty of measuring the strength of concrete in the laboratory. To address these problems, in this study, the potential ability of six machine learning techniques, including ANN, SVM, RF, KNN, XGBoost, and NB, to predict the concrete's tensile strength was investigated by applying 240 datasets obtained using the Brazilian test (80% for training and 20% for test). In conducting the test, the effect of additives such as glass and polypropylene, as well as the effect of wetting and drying cycles on the tensile strength of concrete, was investigated. Finally, the statistical analysis results revealed that the XGBoost model was the most robust one with R2 = 0.9155, mean absolute error (MAE) = 0.1080 Mpa, and variance accounted for (VAF) = 91.54% to predict the concrete tensile strength. This work's significance is that it allows civil engineers to accurately estimate the tensile strength of different types of concrete. In this way, the high time and cost required for the laboratory tests can be eliminated.

• 한국잡초학회지
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• 제32권3호
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• pp.180-187
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• 2012

Panicum maximum, Panicum repens, Imperata cylindrica, Pennisetum polystachion and Cyperus rotundus are five rhizomatous grass weeds that exist and are problematic in the coconut lands of Sri Lanka. Rhizomatous weeds are the most difficult to control because of their vegetative reproduction by underground propagules. Therefore chemical and biological techniques have failed to control these weeds to acceptable levels. Experiments were conducted to investigate the impact of depth of burial, duration of sun drying or duration of air drying rhizomes of the selected weed species on germination. Depth of burial reduced germination of all species. Burying rhizomes at depths less than 10 cm inhibited germination of P. maximum and P. polystachion. Burying depths below 30~40 cm inhibited germination of all species. Sun drying or air drying rhizomes for durations less than 5 days inhibited germination of P. maximum and P. polystachion. Germinations of all species were inhibited by sun drying rhizomes for 15 days or air drying rhizomes for 20 days. Sun drying of rhizomes of all species for five days reduced the moisture content to a greater extent than air drying. The results indicated that burying rhizomes at the depthsbelow 30~40 cm, sun drying rhizomes for durations beyond 15 days or air drying rhizomes for durations beyond 20 days would be effective in controlling germination of these species. The investigations of the experiments also suggest that keeping rhizomes on the soil surface without burying, sun drying rhizomes or air drying rhizomes for durations of 5~15 days would produce weak plants.

• 기술사
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• 제35권2호
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• pp.54-59
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• 2002

• 한국세라믹학회지
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• 제26권5호
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• pp.682-690
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• 1989

Fine mullite powder was prepared by colloidal sol-gel route. Boehmite as a starting material of Al2O3 and silica sol or fumed silica as a starting material of SiO2 were used. $\alpha$-Al2O3, TiO2 and ZrO2 were used as seeding materials. The combination of boehmite and silica was found to be the stoichiometric mullite powder. Techniques for drying used were spray drying, freeze drying, reduced pressure evaporation and drying in a oven. The gelled powder was heated at 130$0^{\circ}C$ for 100min and was attrition-milled for 1~3hrs. The mullite powder obtained was composed of submicrometer, uniform and spherical particles with a narrow size distribution. The mullite powder was characterized by BET, SEM, XRD and IR spectroscopy.

• 펄프종이기술
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• 제31권4호
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• pp.8-15
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• 1999

The effects of Condebelt press drying on the densification of recycled sheets made from KOCC , AOCC UKP and BKP were examined using CLSM (Confocal Laser Scanning Microscope) and thermal image analysis techniques. It was shown that significant improvement in sheet density, compression strength, tensile strength, surface smoothness was obtained by Condebelt drying. Densification effect by press drying was most prominent for recycled KOCC sheets. And this beneficial effect of Condebelt drying of increasing sheet density and strength was shown to provide opportunities of reducing the utilization ratio of AOCC for cost saving.