• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.04a
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• pp.33-33
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• 2001

• Journal of the East Asian Society of Dietary Life
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• v.25 no.6
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• pp.1029-1040
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• 2015

Effects of punching and drying process on quality of Yukwa were determined. Lightness (L) of Yukwa dough with punching was higher than that with no punching. Air cell distribution of Yukwa dough was fine with higher punching. Microstructure of Yukwa dough showed a broken surface structure with increasing punching. Hardness and adhesiveness of Yukwa dough decreased after 5 min of punching and then increased with higher punching. Expansion ratio of Yukwa base with punching at 155 rpm for 5 min was highest among the samples. Appearance of Yukwa base with no punching showed a poor shape and cross section, whereas Yukwa base with punching at 95 rpm for 10 min showed the best appearance and cross section and Yukwa base with punching at 155 rpm for 5 min also showed good appearance. The moisture content of Yukwa Bandegi after 24 hr of drying was 14.93%. Microstructure of Yukwa Bandegi showed a broken surface structure and empty spaces with increased drying time. Expansion ratio of Yukwa base with 24 hr of drying at $40^{\circ}C$ was highest among the samples. Overall, optimum punching conditions were 10 min of punching at 95 rpm or 5 min of punching at 155 rpm and optimum drying condition was 24 hr of drying at $40^{\circ}C$.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.1-7
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• 1997

We show that the usage of the cyclic pressure function in the freeze drying is more effective than the drying rate of the constant pressure process. The ultimate object of this process is to reduce energy costs by shortening the drying time. In this work, the concept of cyclic pressure function to decrease the drying time and the effects of the following factors on drying rate are considered ; pulse type, size in amplitude of pressure, size of intermediate time. Temperature for drying has always been maintained constantly at $20^{\circ}C$ and the pulse type could have found to give useful results than the constant pressure by altering chamber pressure from low pressure to high pressure Also, when the amplitude of the pulse is 0.4 torr and the intermediate time is six hour the drying rate was increased considerably.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.374-379
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• 2016

When using an ionic liquid as co-solvent, the extraction efficiency of anticancer agent paclitaxel from biomass was dramatically improved. However, the residual ionic liquid had a significant negative effect on convenient and feasibility of following concentration and drying steps. In this study, a novel method was developed for the effective drying of the crude extract obtained from biomass extraction with ionic liquid. The residual ionic liquid was easily and conveniently removed by drying alone after pre-treatment and additional washing of a sample with water. The optimal crude extract/water ratio and mixing time for pre-treatment and crude extract/water ratio for additional washing were 1:70 (w/v), 4 min, and 1:100 (w/v), respectively. In the microwave-assisted drying process, the drying time was 9-fold shorter than in the vacuum oven drying process.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.288-301
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• 2002

A vacuum freeze drying experiment of skim milk solution in a cylindrical container is conducted to investigate the multi-dimensional drying characteristics of the process during the primary drying stage. Temperature histories at several positions are measured under the same process condition that is carefully controlled. Then the measured temperature histories at different positions are combined to produce instantaneous temperature distribution fields inside the cylindrical container. Along with the temperature measurement, the mass reduction history of the skim milk solution is also measured. From the measured temperature distribution curved configurations of sublimation interfaces and 2-dimensional heat transfer is inferred. The freeze drying under the present experimental setup is simulated with a calculation program that is based on a finite volume method with a moving grid system. Good agreements between the numerical and experimental results are observed. The present experimental results and the numerical approaches can be useful information in developing the analysis tools for practical vacuum freeze drying processes.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.356-362
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• 2018

Hot pepper is a kind of seasoning vegetables, which is a major item in the Korean vegetable market. Since the use of hot pepper is processed into pepper powder, which is a powder form of dried hot pepper, improvement of quality and productivity of dried hot pepper is important. Therefore, this experiment was conducted to suggest proper drying method by comparing the changes of hot pepper powder ingredients considering production cost according to the drying method. As a drying method, we used sun drying and heat drying which are widely used in practice. We also compared the productivity and quality of dried hot pepper by applying a dehumidifying drying method using a dehumidifier. Drying rate of hot pepper was highest of 85.1% at heat drying. Accordingly moisture content of hot pepper powder was lowest of 13.5% at heat drying. The American Spice Trade Association (ASTA) color value, which influenced the coloring of red pepper, showed higher in heat drying and dehumidified drying treatment than the sun drying treatment. The content of capsaicinoids was higher at sun drying treatment than that of at both heat drying and dehumidified drying treatments. The content of sugar was higher at heat drying and dehumidified drying treatment where drying time was relatively short than that of sun drying treatment. Also, there was no significant difference in sugar content between the two treatments. The production cost of dried hot pepper with dehumidified drying was 9.9% more efficient than heat drying. Through this study, it was found that heat and dehumidified drying method were effective in increasing sugar content and coloring of hot pepper powder. In order to improve the capsaicinoid content of red pepper, it is considered that appropriate drying temperature and drying time should be added in the process of heat drying and dehumidified drying.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.1
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• pp.47-55
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• 2017

The technology for hydrothermal reaction of organic waste is one of the promising process to improve energy efficiency of biomass waste recycling system since moisture contents of treated biomass could be reduced at 40% or less than by dehydration processes. For these reasons, many parts of the world are interested in hydrothermal reaction of organic waste. In this paper, drying performances were evaluated with and without hydrothermal reaction of organic wastes which are sewage sludge and food wastes. For the hydrothermal reaction, organic wastes were treated at $200^{\circ}C$ for 1hr. Drying time of treated organic waste by hydrothermal reaction was reduced. In case of food waste drying at $100^{\circ}C$, drying time of treated wasted was reduced more 52.9% than non-treated. Hence, drying performances of sewage sludge and food wastes should be improved by hydrothermal reaction. Drying rates of treated wastes were considerably increased at preheat period of drying characteristic curve as followings; at $80^{\circ}C$ sludge as 148%, $100^{\circ}C$ sewage sludge as 151%, $80^{\circ}C$ food waste as 209%, $100^{\circ}C$ food waste as 366%. It means the surface area of treated wastes could be increased with destruction of cell membrane by hydrothermal reaction. However, the designer and operator of drying process should be careful, since enhanced drying rate cause the extension the decreasing drying period.

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.42-47
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• 2024

Limonene was separated from waste citrus peels by a vacuum drying process with a venturi, and bioethanol was produced from dried citrus peels. Vacuum drying using venturi was very effective in removing moisture and limonene compared to hot air drying and natural drying. Citrus peels prepared by venturi vacuum drying were the most suitable for ethanol fermentation. The moisture and limonene content of the citrus peels dried for 15 hours were 17.0% and 3.2%, respectively. By venturi vacuum drying, essential oil containing limonene and floral water were obtained, respectively. The amount of essential oil separated by venturi vacuum drying was 4.21 mL essential oil/kg citrus peel, 79.9% of the separated essential oil was limonene.

• Corrosion Science and Technology
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• v.12 no.5
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• pp.203-208
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• 2013

The electrocoating for automotive bodies is pigmented with a mixture of titanium dioxide and kaolin. In this study, the effects of titanium dioxide and kaolin contents in coating on electrodeposition process, drying, and surface properties such as surface roughness, gloss, impact resistance and corrosion resistance were investigated. Titanium dioxide and kaolin in coating do not have a decisive effect on curing reaction during drying and corrosion resistance but on gloss, surface roughness, impact resistance and electrodeposition process of coating. According to its size and shape on coating surface, pigment contents increased during drying process. However, the contents of kaolin and $TiO_2$ in coating didn't affect the corrosion resistance on zinc phosphated substrate, and the curing properties.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.3
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• pp.83-90
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• 2004

Pulp mold is one of the famous environmental friendly materials, which made from re cycled materials such as old newsprints through the environmental friendly processes. Furthermore, the used pulp mold can be easily recycled and the pulp mold itself is biodegradable. However, the higher cost and some deficiency in physical properties of pulp mold have been considered as issues to be overcome for a substitute for polymeric packaging materials such as EPS (Expandable Polystyrene). The way for the optimization of a pulp mold mill was proposed in this report. The possible reduction of drying energy was calculated by using a computer simulation method, which could Provide the detailed information about mass balance of overall process. The simulated results showed a great possible curtailment of production cost by improving the forming systems, for example, increasing the temperature and the dryness of a wet pulp mold.