• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.732-738
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• 2005

The purpose of this study is the presentation of the proper microwave treatment conditions by means of the investigation of the effect of microwave irradiation on the dewaterability and dryability of sludge. For the improving of dewatering efficiency of sludge using the microwave, the proper time of microwave irradiation is very important. The dewatering efficiency of thickening sludge conditioned by microwave irradiation for proper time was considerably improved with reducing of capillary suction time from 52.3 sec to 30.8 sec, and the sludge conditioned by microwave irradiation had contained the moisture of 81.4% after that pressure filtrationed. The result of drying characteristics of dewatered sludge using the microwave irradiation and furnace heating, for drying of sludge to moisture of below 55%, microwave irradiation time was required 3 min, whereas, furnace heating was required 40 min at $105^{\circ}C$, 20 min at $170^{\circ}C$ and 9 min at $300^{\circ}C$, respectively. We certified that the drying of dewatered sludge using the microwave irradiation was effectively reduction of moisture of sludge compare to traditional heating method.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.389-395
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• 2016

Purpose: Drying is one of the most widely used methods for preserving agricultural products or food. The main purpose of drying agricultural products is to reduce their water content for minimizing microbial spoilage and deterioration reaction during storage. Methods: Although numerous drying methods are successfully applied to dehydrate various agricultural products with little drying time, the final quality of dried samples in terms of appearance and shape cannot be guaranteed. Therefore, based on published literature, this review was conducted to study the drying characteristics of various agricultural products when different drying methods were applied. Results: An increase in the drying power of sources-for example, increase in hot air temperature or velocity, infrared or microwave power-and the combination of drying power levels can reduce the drying time of various agricultural products. In addition, energy efficiency in drying significantly relies on the compositions of the dried samples and drying conditions. Conclusions: The drying power source is the key factor to control entire drying process of different samples and final product quality. In addition, an appropriate drying method should be selected depending on the compositions of the agricultural products.

• Korean Journal of Metals and Materials
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• v.47 no.8
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• pp.516-521
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• 2009

In this study we report a rapid synthesis of nanoporous organo-functional silica (OFS) with unimodal and bimodal pore structures encompassing pores ranging from meso-to macroscale. The problems of tediousness and high production cost in the conventional syntheses are overcome by co-condensation of an inexpensive inorganic precursor, sodium silicate with an organosilane containing trimethyl groups. The insitu covalent anchoring of the non-polar trimethyl groups to the inner pore walls prohibits irreversible shrinkage of the wet-gel during microwave drying at ambient pressure and thus larger size pores (from ca. 20 to ca. 100 nm) can be retained in the dried silica. The drying process of the silylated wet-gels at an ambient pressure can be greatly accelerated upon microwave exposure instead of drying in an oven or furnace. Using this approach, anoporous and superhydrophobic silicas showing a wide variation in texture and morphology can be readily synthesized in roughly two hours. The effects of various sol-gel parameters solely on the textural properties of the organo-functional silica (OFS) have been investigated and discussed.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.430-434
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• 2018

In this study, an effective diffusion coefficient and mass transfer coefficient were investigated in microwave-assisted drying of paclitaxel for removal of residual methylene chloride. At all the temperatures (35, 45, and $55^{\circ}C$), a large amount of the residual methylene chloride was initially removed during the drying, and the drying efficiency increased when increasing the drying temperature. The effective diffusion coefficient ($1.299{\times}10^{-13}{\sim}2.571{\times}10^{-13}m^2/s$) and mass transfer coefficient ($1.625{\times}10^{-11}{\sim}4.857{\times}10^{-11}m/s$) increased with increasing drying temperature. The small Biot number (0.0100~0.0151) indicated that the process of mass transfer was externally controlled.

• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.99-103
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• 2021

The purpose of this study was to investigate how microwave drying, a method to minimize the scent and physicochemical changes of the final products, affects the quality characteristics of various herbs according to treatment intensity (pulse and continuous waves) and time. In the current study, different physicochemical qualities, such as weight change, moisture content, water activity, color, and microbial growth, of five different Korean herbs were analyzed after microwave drying. The results clearly showed that the pulse wave method was a more effective approach than the continuous wave method for maintaining the physicochemical properties of herbs. Furthermore, pulse wave drying lead to efficient microbial death in various herbs after a short time. Thus, microwave drying with a pulse wave can be applied to herb processing and packaging technology while minimizing the quality changes of herbs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.501-502
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• 2012

• International Journal of Industrial Entomology and Biomaterials
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• v.40 no.1
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• pp.22-27
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• 2020

Silkworm powder was prepared from 3^rd day of 5^th instar silkworm through various drying technology including freeze drying, hot wind drying, infrared drying, and microwave drying. The shape of silkworm dried was different with the drying methods. Freeze drying and microwave drying silkworm looked its original form, but hot wind drying and infrared drying silkworm looked shriveled and crumpled. The color of silkworm powder freeze-dried changed from yellowish green to hazel with lowering freezing temperature. Heavy metals including Pb, Cd, As, and Hg were lower the food criteria. The results of 1-deoxynojirimycin analysis was shown that BaekOkJam and GoldenSilk silkworm powder was satisfied the criteria of functional food, but YeonNokJam silkworm powder was lower than the criteria. The amino acid composition of silkworm was similar regardless of the frozen temperature in freeze drying process.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.380-386
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• 1995

An attempt was made to determine the effects of drying methods including shady air drying, presteamed and shady air drying, microwave drying, and freeze drying on the volatile flavor components with Commelina communis L.. Essential oils from the samples were isolated by simultaneous steam distillation-extraction(SDE) method using diethyl ether as solvent. Concentrated samples were analyzed by gas chromatography(GC) and combined gas chromatography-mass spectrometry(GC-MS). Respective 29, 47, 36, and 24 volatile flavor components were identified in shady air dried samples, presteamed and shady air dried samples, microwave dried samples, and freeze dried samples. The kinds and amounts of volatile flavor components were evidently depended upon the drying methods. 6,10,14-trimethylpentadecanone was regarded as the most abundant component in shady air dried samples, 6,10,14-trimethyl-2-pentadecanone in presteamed and shady air dried samples, neophytadiene in microwave dried samples, and ethyl acetate in freeze dried samples.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.631-637
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• 1999

An investigation was carried out to study the effects of aging time, storage temperature, and drying type on the physical, chemical and sensory properties of Korean rice cake. Water content and cooking properties were significantly influenced by aging time and storage temperature. However, aging time did not affect the soup turbidity. Difference in water content was noticeable by drying type. The microwave treated rice cake (MW) showed a higher water content than the other ones. The lightness (L-value) was not affected by the aging time and drying type. Rice cake storaged at 4oC showed the highest L-value. The textural properties of rice cake were influenced by the all sources of variables. There was a significant difference in hardness between microwave and hot air treated rice cake (MWH), and microwave and vacuum treated rice cake (MWV). In the sensory properties, mean intensities of all attributes except chewiness were significantly different among drying types. The MWV showed a higher acceptability than the MW and the MWH. Scanning electron photomicrographs revealed that the MWV has more porous structure. The MWV was the most desirable one as determined by the physical, chemical and sensory evaluation.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.103-109
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• 1998

For the purpose of improving quality of dried anchovy, raw anchovies after hot air drying were subjected to six different processes: 5 min microwave and 1 min holding-12 times (MW5), 10 min microwave and 1 min holding-6 times (MW10), 5 min microwave with hot air and 1 min holding-12 times (MWH5), 10 min microwave with hot air and 1 min holding-6 times (MWH10), 5 min microwave vacuum and 1 min holding-12 times (MWV5), 10 min microwave vacuum and 1 min holding-6 times (MWV10) at 100 Watt and 2450MHz. There were no significant effects of different processes on water content, pH, color, acid value and volatile basic nitrogen. The sum of fatty acids on commercial anchovy occupied 38.34% of saturates 22.91% of monoenes and 22.91% of polyenes and dried anchovies subjected to microwave processes had similar compositions. Dominant fatty acids were palmitic acid and docosahexaenoic acid in each process. Among the free amino acids, alanine, arginine, lysine and leucine were dominant in all processes. Dried anchovies showed little significant differences in texture in all processes. Sensory evaluation data showed that the quality of dried anchovy subjected to microwave process was acceptable and microwave vacuum process was the most desirable one.