• KSBB Journal
• /
• v.14 no.5
• /
• pp.561-565
• /
• 1999

Optimum conditions for vacuum-drying ad cultivation of yeast cells for the production of active dry yeast were examined. At lower temperature, more drying time was required to dry the yeast pellet to reach the desirable water content(8%). Optimum temperature of vaccum oven and time for drying was 63$^{\circ}C$ and 90 min, respectively. Optimum medium composition for flask culture using cane molasses as the substrate were 0.25% sugar, 0.013% $K_2$HPO$_4$, 0.1% $K_2$HPO$_4$. and 0.125% (NH$_4$)$_2$SO$_4$. Culture temperature $25^{\circ}C$ gave the highest survival rate of dired yeast. After finishing fed-batch culture and the culture was left in the fermentor without adding any sugar or nutrient, survival of the dried yeast harvested from the fermentor increased to 86.0% after 36 hr. It was also observed that the yeast cells with higher budding rates showed lower survival rate.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2005.05a
• /
• pp.25-28
• /
• 2005

This study shows the early quality improvement of concrete with calcium sulfa aluminate(CSA). For the properties of slump, plain concrete incorporating BS $35\%$ and UP $15\%$ resulted in high fluidity compared with OPC without any admixture. As displacement ratio of CSA increased. the fluidity decreased. The fluidity also declined with setting time. Increase of incorporation ratio of CSA declined bleeding and accelerated setting time. Importantly, using more CSA helped to improve early compressive strength and decrease drying shrinkage. In term of water curing, drying shrinkage hardly ever occurred.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.93-98
• /
• 2002

The effects of polymer-cement ratio, antifoamer content and shrinkage-reducing agent content on the air content, setting time and drying shrinkage of polymer-modified mortars using redispersible polymer powder are examined. As a result the air content of the polymer-modified mortars using redispersible polymer powder tend to decrease with increasing polymer-cement ratio and antifoamer agent content. Regardless of the antifoamer content, the setting time of the polymer-modified mortars using redispersible polymer powder tend to delayed with increasing polymer-cement ratio. Irrespective of the antifoamer content, the drying shrinkage of the polymer-modified mortars using redispersible polymer powder tend to decrease with increasing polymer-cement ratio and shrinkage-reducing agent content.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.296-299
• /
• 2004

The effects of polymer-cement ratio, antifoamer content and shrinkage-reducing agent content on the setting time and drying shrinkage of high-fluidity polymer-modified mortars using redispersible polymer powder are examined. As a result, the setting time of the high-fluidity polymer-modified mortars using redispersible polymer powder tend to delayed with increasing polymer-cement ratio, regardless of the antifoamer conten,. Irrespective of the antifoamer content, the drying shrinkage of the high-fluidity polymer-modified mortars using redispersible polymer powder tend to decrease with increasing polymer-cement ratio and shrinkage-reducing agent content.

• Plant Resources
• /
• v.5 no.2
• /
• pp.124-140
• /
• 2002

The effects of drying agents and ethyl alcohol treatment on the flower color of Gentiana uchiyamai. The flower color was not much changed in flower sheet, in the case of absorbtion papers only. The color was least changed in Korean and China hwasunjis, in the case of absorbtion papers and silica gel treatment. The color was less changed in flower sheets, window papers, and China hwasunjis, and was most changed in newspapers, in the case of absorbtion papers and Na$_2$SO$_4$ treatment. The color was least changed in China hwasunjis, and most changed in dampened papers, in the case of absorbtion papers and CaO treatment. The color tended to change far from the original one, as treatment time got longer, in the case of 0.01M and 0.lM of tartaric acid. The longer the treatment time and the bigger the concentration of ethyl alcohol, the bigger flower color.

• Journal of Pharmaceutical Investigation
• /
• v.30 no.4
• /
• pp.295-297
• /
• 2000

A new method to evaluate erosion of biodegradable polymer, polyanhydrides, was developed. The polymer devices were prepared with the melt-casting method and weight loss was accurately measured after agitating the devices in buffers (pH 1-9), and removing the device at selected time intervals and freeze-drying the device. The erosion rate was estimated from the plot of the weight loss(%) of device as a function of time. The freeze-drying technique used in this study is particularly useful for estimating the erosion rate of biodegradable polymer.

• Journal of Biosystems Engineering
• /
• v.29 no.3
• /
• pp.261-266
• /
• 2004

This study was Performed to classify the acoustic emission(AE) signal due to surface cracking and moisture movement in the flat-sawn boards of oak(Quercus Variablilis) during drying using the principal component analysis(PCA) and artificial neural network(ANN). To reduce the multicollinearity among AE parameters such as peak amplitude, ring-down count event duration, ring-down count divided by event duration, energy, rise time, and peak amplitude divided by rise time and to extract the significant AE parameters, correlation analysis was performed. Over 96 of the variance of AE parameters could be accounted for by the first and second principal components. An ANN analysis was successfully used to classify the Af signals into two patterns. The ANN classifier based on PCA appeared to be a promising tool to classify the AE signals from wood drying.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.1
• /
• pp.71-76
• /
• 2011

An efficient nucleophilic [$^{18}F$]fluorination has been studied to reduce byproducts and preparation time. Instead of conventional aqueous solution of $K_2CO_3-K_{222}$, several organic solution containing inert organic salts were used to release [$^{18}F$]fluoride ion and anion bases captured in the polymer cartridge, concluding that methanol solution is the best choice. Comparing to azeotropic drying process, one min was sufficient to remove methanol completely, resulting in about 10% radioactivity saving by reducing drying time. The polymer cartridge, Chromafix$^{(R)}$ (PS-$HCO_3$) was pretreated with several anion bases to displace pre-loaded bicarbonate base. Phosphate bases showed better results than carbonate bases in terms of lower basicity. tert-Butanol solvent used as a reaction media played another critical role in nucleophilic [18F]fluorination by suppressing eliminated side product. Consequent [$^{18}F$]fluorination under the present condition afforded fast preparation of reaction solution and high radiochemical yields (98% radio-TLC, 84% RCY) with 94% of precursor remained.

• Microbiology and Biotechnology Letters
• /
• v.49 no.2
• /
• pp.201-209
• /
• 2021

Agarwood (Aquilaria spp) has high economic value. However, essential oil production from agarwood is a time-consuming process. Additionally, agarwood leaves have not been utilized even though they contain various bioactive ingredients. In this study, agarwood leaves were fermented using Lactobacillus plantarum ATCC 8014 with or without Stevia (4, 8, and 12%; v/v). The fermented fluid was mixed with maltodextrin (15%; w/v) and subjected to spray drying (inlet temperature, 120℃; outlet temperature, 65-70℃). The contents of polyphenols, polysaccharides, saponins, and flavonoids and the viability of L. plantarum were determined. Fermentation enhanced the levels of bioactive compounds. The contents of polyphenol (69.19 ± 4.05 mg GAE/g of sample), polysaccharide (20.75 ± 0.98 mg GE/g of sample), saponin (305.23 ± 4.21 mg OAE/g of sample), and flavonoid (7.86 ± 0.72 mg QE/g of sample), and the viability of L. plantarum (8.72 ± 0.17 log CFU/ml) were markedly upregulated in the samples containing Stevia (12%; v/v). This indicated that the supplementation of Stevia during fermentation decreases the fermentation time (9 h), upregulates bioactive compound production in agarwood leaves, enhances microencapsulation during spray drying, and increases the viability of L. plantarum under simulated gastric digestion conditions.

• Korean Journal of Plant Resources
• /
• v.35 no.6
• /
• pp.778-784
• /
• 2022

Wild vegetables, such as Cirsium setidens, and Aster scaber, are commonly distributed as dried materials because the wild vegetables lose their freshness quickly after harvest and distribution. Dried wild vegetables require rehydration to use as a food ingredient, and the quality of rehydrated wild vegetables is affected by pre-drying and drying methods. Here, we introduce the newly developed pre-drying and drying method, termed "micro oil sprayed thermal air (MOTA) technique". The three wild vegetables processed by the MOTA technique showed improved rehydration rate and reduced time to achieve maximum rehydration rate. Color characteristics were also improved in C. setidens. These results indicate that the MOTA technique improves the overall quality of rehydrated wild vegetables. It is expected that our findings could enhance the marketability of dried wild vegetables by improving overall quality and reducing preparation time.