• Food Science and Preservation
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• v.11 no.4
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• pp.508-515
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• 2004

In this study, salting conditions and dehydration methods were investigated. Salting time, concentration and temperature could be considered to variables in salting conditions. The diffused salt amounts to beef jerky depending on time are sharply increased in two hours. This result is caused by the difference decrease of concentration gradient between bulk solution and beef jerky. The increase of salting concentration and temperature resulted also in the increase of a diffused salt. The deeper bulk concentration made diffusion to beef easily with the bigger driving force and the movement of molecules is more active according to temperature increase. Dehydration is conducted with various methods such as natural drying, cold air drying and hot air drying. Comparing with color and texture among the drying methods, cold air drying showed superior quality in color and texture. Beef jerky by cold air drying colored more reddish than other drying methods and good cutting shear stress and tensile strength. In case of hardness and chewiness, hot air drying method showed the highest value, which means the worst texture.

• Food Science and Preservation
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• v.22 no.1
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• pp.1-11
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• 2015

Raspberries are a good resource of polyphenols and have a powerful antioxidant activity, but shelf life for raspberries is short which brings a lot of economic losses. In this study, we try to use cool-air ($20{\sim}40^{\circ}C$) or hot-air ($60{\sim}100^{\circ}C$) to produce semi-dried raspberries with extended shelf life, and to determine the best method for improving fruit quality by minimizing nutrient losses during drying processes. The effects of process variables (drying temperature and processing time) on the quality of final dried raspberries were investigated. Response surface methodology was employed to establish statistical models for simulating the drying processes, and the moisture residue content and the loss ratios of total phenolic content (TPC), vitamin C (VC), and ellagic acid (EA) that result from the drying processes of raspberries using either hot or cool-air were predicted. Superimposed contour plots have been successfully used in the determination of the optimum zone within the experimental region. Optimal conditions determined for achieving minimal losses of TPC, VC, and EA, and a final moisture residue of 45% using the hot-air drying process were a drying temperature of $65.75^{\circ}C$ and a processing time of 4.3 hr. While for the cool-air process, the optimal conditions predicted were $21.3^{\circ}C$ and 28.2 hr. Successful application of response surface methodology provided scientific reference for optimal conditions of semi-drying raspberries, minimizing nutrient losses and improving product quality.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.676-685
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• 1989

Optimal operating conditions of on-farm red pepper dryer were searched by using the simulation-optimization algorithm combining the drying and quality deterioration models of red pepper with Box's complex method. Determination of control variables such as air temperature, air recycle ratio and air flow rate was based on a criterion of minimizing energy consumption under the constrainst conditions that satisfied the specified color retention of carotenoids. As quality constraint was stricter, energy consumption increased and total drying time decreased with lower recycle ratio and higher air flow rate Product mixing during drying was found to be able to improve the energy efficiency and product quality. Currently used air flow rate was assessed to be increased for the optimal operation. Two stage drying at the fixed optimal air flow rate was proven to be useful means for further saying of energy consumption. In the optimal bistaged drying, the second stage began at about one third of the total drying time and low air temperature in the first stage Increased to a high value and air recycle ratio increased slightly in the second stage. Optimal control variable scheme could be explained by the dryer performance and the carotenoids destruction kinetics in red pepper drying.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.563-566
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• 2000

The study is to examine the drying shrinkage reducing method of mortar using organic shrinkage reducing agent. According to the experiment result, when 2% and 4% of organic shrinkage reducing agent were added, 40% and 50% of the shrinkage rate of mortar were obtained. Also, in the cracking test of plate-shape specimen, the usage of shrinkage agent 2% reduced about 60% of the total cracking length compare to total cracking length the usage of portland cement, the usage of shrinkage agent 4% was not happened crack until 90 days. Accordingly, the usage of shrinkage agent show good effect in prevention of crack.

• Textile Coloration and Finishing
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• v.9 no.6
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• pp.74-78
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• 1997

This study was performed to obtain the basic data of the effect of antimicrobic finishing on chrome-tanned leather for apparel. This study was to examine the effect of conditions of antimicrobic finishing on content of antimicrobic agents in the specimen by analysis and on the antimicrobic activity of specimens by means of shake flask test. The optimum conditions of antimicrobic finishing were found to be ; the concentration of Si-QAC-0.5%(o.w.f.), treating time-30minute, and drying method-air drying.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.393-394
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• 2000

The magnetic alloy of $Nd_{2}Fe_{14}B$-type was synthesized by a mechano-chemical method, including the processes of spray-drying, de-binding, milling, $H_{2}$- and Ca-reduction and washing. The very fine $Nd_{2}Fe_{14}B$ particles smaller than $1\mu\textrm{m}$ could be achieved without the inevitable pulverization step in conventional processes.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.186-193
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• 1996

Several chitosan beads were prepared by W/O emulsion and capillary extrusion methods. The surface structures were observed through SEM pictures, the surface areas were determined by BET method, the available amine contents were measured by picric acid titration method, and the results were correlated each other. The beads from W/O emulsion method were smaller in size but had higher hardness, surface area, and available amine contents than the ones from capillary extrusion method. Moreover, the surface area, available amine contents, apparent density and the hardness showed large differences according to the drying processes. As compared between the solvent dehydration and the freeze drying technique in W/O emulsion method, the former showed higher surface area, higher available amine contents and hardness than the latter. SEM pictures revealed that in case of solvent dehydration method, very small pores existed, whereas in case of freeze drying method, cell-like pores existed on the surface. The results of picric acid titration showed that the beads dried by solvent dehydration method were 10 times higher in amine contents than those from freeze drying method, and the amount of amine contents were increased as the surface area was increased. After fluorescamine was reacted with chitosan beads, the fluorescence labeled beads were observed through fluorescence microscope. The results showed that most of primary amine existed on the surface of beads and pores.

• Journal of Korean Biological Nursing Science
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• v.13 no.1
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• pp.8-15
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• 2011

Purpose: The purpose of this study was to analyze effects of hand drying methods after hand-washing. Hand drying methods consisted of spontaneous evaporation, paper towel, hand dryer with rubbing, and hand dryer without rubbing. Methods: The research design was a crossover design. The subjects were eighteen university students and randomly assigned in four group. Each group had the schedule of treatment. The schedule tested one drying method per a day and proceeded for 4 days. The data collection was performed from July 27 to July 30, 2010. Data were analyzed by Kruskal-Wallis, Mann-Whitney and Wilcoxon test. Results: There was significant difference between the after CFU between natural dry, paper towel, air dryer with hand rubbing, and air dryer without hand rubbing(p=.006). The after CFUs of paper towel, natural dry and air dryer without hand rubbing groups were statistically less than air dryer with hand rubbing group. Conclusion: It was shown that the paper towel, spontaneous evaporation and without rubbing hand dryer are effective hand drying interventions on reducing CFU on hand. However additional researches with large sample and strict methodology are needed.

• Journal of the Korea Institute of Building Construction
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• v.16 no.3
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• pp.211-217
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• 2016

In this research, the performance of surface covering technique using a white-colored bubble sheet on reducing the cracking due to the plastic, and drying shrinkages for high rise building construction were evaluated by comparing the exposed surface without any surface treatment. From the results of the experiment conducted during fall season, desired results of decreased numbers, length, maximum width, and area of cracking were obtained without a significant difference on heat of hydration and cumulative temperature. Therefore, it is considered that the surface covering technique using bubble sheet is an appropriate method for preventing plastic and drying shrinkage cracking at fall season concrete construction.

• Journal of the Korean Society of Food Culture
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• v.8 no.4
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• pp.331-335
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• 1993

This study was performed to improved the quality of dried persimmon. For this, the investigation of quality factor and processing experiments were performed. The moisture contents of dried persimmons were 30 to 36% and it was the most important component of the quality. Tannin contents were 0 to 20% and non-treated persimmon had higher tannin contents than treatment of carbon dioxide and alcohol. Total sugar contents were 55 to 60% and it was composed in glucose and fructose. Processing of dried persimmon by artificial-drying seemed to be useful when it needed to shorten the drying time or it continued rainy day during sun-drying. From the result of quality evaluation, sliced dried persimmon was better than whole dried persimmon in quality, so the sliced dried persimmon was expected that it has a little marketability.