• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.65-68
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• 2008

Generally CCM (cold crucible melting) is not suitable for melting glass. However, in this study we described the quantitative relationship between the basic property of glass and power balance, the power absorption in the melt, the losses in the coil and the cold crucible, for melting glass in CCM. The dependence of power balance on the applied frequency and the electric conductivity has been found. Above 300 kHz, the glass (B) contained alkali ion which has the low resistance $3.0{\Omega}{\cdot}cm$ at $900^{\circ}C$ and $1.36{\Omega}{\cdot}cm$ at $1,100^{\circ}C$ was melted easily and 60% of the overall power was absorbed in the melt and 30% and 10% of the overall power was lost in the cold crucible and coil respectively. Under the same condition, the glass (A) contained non-alkali ion was not melted easily and 50% of the overall power was absorbed in the melt and 40% and 10% of the overall power was lost in the cold crucible and coil respectively. In conclusion, the small absorbed power of the overall power in melt prevented a successful melting as for glass A, and the successful melting depends on the relative size of the absorbed power in melt irrespective of the melting volume. Hence, as typical for direct induction heating method(CCM), the successful melting strongly depended on the chosen working frequency based on electric conductivity of glass, power balance and the control of the critical power which was absorbed in melt.

• Korean Journal of Acupuncture
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• v.38 no.4
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• pp.282-289
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• 2021

Objectives : The purpose of this study is to construct a model of the possible thermal runaway of electronic moxibustion and to implement an appropriate risk management method. Methods : To reproduce the system error situation of the electronic moxibustion circuit equipped with microcontroller unit, temperature sensor and heater, a code was set to disable the signal input to temperature sensor and maintain "high" heating signal to heater. The temperature change of electronic moxibustion was compared between 3 types of heater module; module 1 consisting of a combination of heater+0 ohm+0 ohm resistance, module 2 consisting of a combination of heater+Polymeric Positive Temperature Coefficient (PPTC)+0 ohm resistance, and module 3 consisting of a combination of heater+PPTC+10 ohm resistance. The temperature change was measured using a polydimethylsiloxane (PDMS) silicone phantom. After maintaining surface temperature of the phantom at 31~32℃ for 20 seconds, electronic moxibustion was applied. After operating electronic moxibustion, the temperature change was measured for 660 seconds on the surface and 900 seconds at 2 mm depth. Results : Regardless of the module type, the time-dependent change in temperature showed a rapid rise followed by a gentle curve, and a sharp drop in temperature after reaching the maximum temperature about 10 minutes after the switching the moxibustion on. Temperature measured at the depth of 2 mm below the surface increased slower and to a lesser extent. Module 1 reached highest peak temperature with largest change of temperature at both depths followed by module 2, and 3. Conclusions : Through the combination of PPTC+resistance with the heater of electronic moxibustion, it is possible to limit the rise in temperature even with the software error. Thus, this setting can be used as an independent safety measure for the electronic moxibustion control unit.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.39-47
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• 2018

This study was carried out to investigate the applicability of alternating temperature control during night time in a nursery seedling production. Three groups of samples were exposed to three different environmental conditions for 6 days from 18:00 to 09:00; one was constantly 15 ℃, another was alternating between 15 ℃ for 2 hours and 11 ℃ for 2 hours, and the other was alternating between 15 ℃ for 2 hours and 11 ℃ for 4 hours. Leaf temperature and stem temperature was measured in real time. The influence of cold stress was analyzed by flavonoid content and growth of tomato seedling. The temperature of leaves and stem became equal to the ambient temperature over time, furthermore, there was no significant difference among the treatments. In conclusion, it is considered that heating costs can be saved considerably, as the alternating temperature has fewer effects on cold stress reaction by tomato seedling growth.

• Korean Journal of Organic Agriculture
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• v.10 no.3
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• pp.87-99
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• 2002

The development of insecticidal soaps made by various fatty acids and organic control for insect by using of insecticidal soap(fatty acid salts) were employed. And the results were as follows: 1. To determine the input volume of potassium hydroxide for saponification of fatty acids, there were compared to individual acid value of fatty acids. in case of coconut fatty acids for saponification was 266.3 mg of potassium hydroxide(266 g/1kg of fatty acid) was calculated. 2. To make the 25% soap content by coconut fatty acids, there was required for the 266g of potassium hydroxide and 3,459 liter of soft water. Then the liquor of soap was 4,644 liter. 3. The progress of insecticidal soap made by fatty acids was accomplished indirect heating and stirring reactor (1)to make the volume of potassium hydroxide solution and warming up(90$^{\circ}$) (2)input volume of individual fatty acid (3)more than 30 min stirring reaction (4)cooling progress. 4. Insecticidal value of insecticidal soap was observed more than 92% the dilution of 50 dilution solution in consecutive 5 days of 2 treatments of the 25% soap made by coconut fatty acids on the red pepper. And insecticidal value of insecticidal soap was observed more than 94% the 100 dilution solution in consecutive 5 days of 3 treatments of the 25% soap made by coconut fatty acids on red pepper and cabbage. 5. The treatment of two times of 25% soap made by coconut fatty acids at the 50 dilution solution and 100 dilution solution in spider mite on red bean has 100% insecticidal value. 6. There was no observation phytotoxic sypmtons on red pepper in field, except for 25% soap made by carprylic acid. 7. Over the two times over 0.1% in addition of isopropyl alcohol was to improvement the insecticidal effect, but there was no effect in addition of diatomaceous earth.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.272-279
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• 2018

The high pressure processing (HPP) is a technology which can preserve the quality of foods, such as the fresh taste, incense, texture, vitamin content, and so on, by minimizing the heating process. It does so by applying an instantaneous and uniform pressure that is the same as the water pressure that is 60 km deep in the sea. HPP is a technology that can inhibit food poisoning and spoilage caused by microorganisms and is currently an actively studied area. In this study, we investigated the effects of a high pressure treatment (0, 4, 6 min) on sliced ham, which is a typical meat product, at 600 MP a were tested for their effect on freshness. Moisture contents varied from 48 to 69%, salinity varied from 1.07 to 1.11%, and the pH decreased from 6.4~6.5 to 6.1~5.15. However, there was no difference between the control and treatment groups. General bacteria stored at $20^{\circ}C$ after hyper-pressure treatment were found to have no significant microorganisms in all groups until 4 weeks. but exceeded $10^5$ in control group and HPP 6 min treatment group from 5 weeks, At week 7, it was found to exceed $10^6$. The results indicate it was not possible to ingest food in the 4-and 6 minute treatment groups. Coliform was not observed in all groups despite observing for a total of 7 weeks at $20^{\circ}C$ weight test. VBN, a method used to determine the protein freshness of meat, showed a VBN value of less than 1 mg% until the fourth week and a value of 1 to 2 mg% after 5 weeks. The TBA was used as an index of the degree of fat acidosis in the meat tissues. The results showed it was below 0.18 mgMA / kg until the end of 7 weeks; this value was within the range for fresh meat, and there was no difference in treatment group. In this experiment, deformation of the packaging material did not occur and no swelling occurred due to the generation of gas. It is believed that the basic preservation effect was achieved only by blocking with the air due to the close contact of the packaging material.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1102-1139
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• 2002

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2000 and 2001 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD technologies were widely applied for developing facilities and their systems. (2) Most of papers related with heat transfer analysis and heat exchanger shows dealt with convection, evaporation, and channel flow for the design application of heat exchanger. The numerical heat transfer simulation studies have been peformed and reported to show heat transfer characteristics. Experimental as well as numerical studies on heat exchanger were reported, while not many papers are available for the system analysis including heat exchanger. (3) A review of the recent studies on heat pump system shows that performance analysis and control of heat pump have been peformed by various simulations and experiments. The research papers on multi-type heat pump system increased significantly. The studies on heat pipe have been examined experimently for change of working characteristics and strut lure. Research on the phase change has been carried out steadily and operation strategies of encapsulated ice storage tank are reported experimentally in several papers. (4) A review of recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. Evaporation and condensation heat transfer characteristics are investigated for tube shapes and new alternative refrigerants. Studies on components of refrigeration/air conditioning system are carried to examine efficiency for various compressors and performance of new expansion devices. In addition to thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out, however research works on two-phase flow seemed to be insufficient. (5) A review of the recent studies on absorption cooling system indicates that heat and mass transfer phenomena have been investigated to improve absorber performance. Various experimental data have been presented and several simulation models have been proposed. A review of the recent studies on duct and ventilation shows that ventilation indices have been proposed to quantify the ventilation performance in buildings and tunnels. Main efforts have been focused on the applications of ventilation effectiveness in practice, either numerically using computational fluid dynamics or experimentally using tracer gas techniques. (6) Based on a review of recent studies on indoor thermal environment and building service systems, research issues have mainly focused on many innovative ideas such as underfloor air-conditioning system, personal environmental modules, radiant floor cooling and etc. Also, the new approaches for minimizing energy consumption as well as improving indoor environmental conditions through predictive control of HVAC systems, various activities of building energy management and cost-benefit analysis for economic evaluation were highlighted.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.673-680
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• 2009

This study was conducted to screen for plant food materials that improve human intestinal microflora, especially microorganisms associated with obesity. Among 30 tested plant food materials, the extract of Schizandra chinensis inactivated Eubacterium limosum, Bacteroides fragilis and Clostridium spp. Additionally, S. chinensis extract was also found to have a growth-promoting effect on Bifidobacterium spp.. The antimicrobial activity and antioxidant activity of the water extract did not decrease in respond to heating. Additionally, the water extract of S. chinensis did not show a toxic effect on the growth of Caco-2 cells. In vivo feeding tests were performed to investigate the influence of extract on the intestinal microflora in rats. Although the extract did not reduce obesity induced by a high fat diet, it led to significant increase in the population of Bifidobacterium spp. and a decrease in the population of Clostridium spp. in rats. Taken together, these results indicate that S. chinensis could be useful as a functional food component to control intestinal microbial flora.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.202-209
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• 1996

The environment in composting greenhouse is very different with the traditional greenhouse by biothermal energy and $CO_2$ concentration. This experiment aimed to investigate the environmental effects on the growth and development of tomato grown at composting greenhouse. The room temperature is not different between two greenhouses because of heating and ventilation, but the soil temperature in composting greenhouse is about 7$^{\circ}C$ to 15$^{\circ}C$ higher than that of traditional greenhouse. The emission concentration of ammonia gas is the highest, 117.3ppm, at the 6th day starting the digest, and were gradually lowered from 7th day, 11 became 15.7ppm at the 16th day. The concentration of $CO_2$ in composting greenhouse were 250 to 2000ppm higher than that of traditional greenhouse for 4 months starting digest. The growth and development of tomato grown at composting greenhouse was better than that of traditional greenhouse. The yield in composting greenhouse was also better than that of traditional greenhouse. The sugar contents of tomato grown at composting greenhouse became about 1 $^{\circ}$Brix higher than that of traditional greenhouse.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.1-8
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• 2017

We investigated the effect of silicate coating of rice seeds on bakanae disease incidence and the quality of seedlings raised in seedling boxes and transplanted into pots. The silicate-coated rice seed (SCS) was prepared as follows. Naturally infested rice seeds not previously subjected to any fungicidal treatment were dressed with a mixture of 25% silicic acid at pH 11 and 300-mesh zeolite powder at a ratio of 50 g dry seed - 9 mL silicic acid - 25 g zeolite powder. The following nursery conditions were provided : Early sowing, dense seeding in a glass house with mulching overnight and no artificial heating, which were the ideal conditions for determining the effect on the seed. The nursery plants were evaluated for Gibberella. fujikuroi infection or to determine the recovery to normal growth of infected nursery plants in the Wagner pot. Seedlings emerged 2-3 days earlier for the SCS than they did for the non-SCS control, while damping-off and bakanae disease incidence were remarkably reduced. Specifically, bakanae disease incidence in the SCS was limited to only 7.8% for 80 days after sowing, as compared to 91.6% of the non-SCS control. For the 45-days-old SCS nursery seedlings, the fresh weight was increased by 11% and was two times heavier, with only mild damage compared to that observed for non-SCS. Even after transplanting, SCS treatment contributed to a lower incidence of further infections and possibly to recovery of the seedlings to normal growth as compared to that observed in symptomatic plants in the pot. The active pathogenic macro-conidia and micro-conidia were considerably lower in the soil, root, and seedling sheath base of the SCS. In particular, the underdeveloped macro-conidia with straight oblong shape without intact septum were isolated in the SCS ; this phenotype is likely to be at a comparative etiological disadvantage when compared to that of typical active macro-conidia, which are slightly sickle-shaped with 3-7 intact septa. A active intact conidia with high inoculum potential were rarely observed in the tissue of the seedlings treated only in the SCS. We propose that promising result was likely achieved via inhibition of the development of intact pathogenic conidia, in concert with the aerobic, acidic conditions induced by the physiochemical characteristics associated with the air porosity of zeolite, alkalinity of silicate and the seed husk as a carbon source. In addition, the resistance of the healthy plants to pathogenic conidia was also important factor.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.244-252
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• 2009

This research aims at comparison of climatic conditions of sweet pepper's greenhouse between Korea (KOR) and the Netherlands (NL) to find out the reason of much lower yield in KOR than NL focus-ing on greenhouse climatic conditions. Hence, greenhouse climate data were obtained from each one commercial glasshouse in both countries. The crops (cv. 'Derby') were grown on rockwool slab with two stems per plant with 3.75plants/$m^2$ in KOR and three stems per plant with 2.5plants/$m^2$ or four stems per plant with 1.875plants/$m^2$ in NL. Even though plant density was differed but stem density was on the same to 7.5stems/$m^2$. There was no significantly difference on weekly growth of sweet pepper plant both countries, whereas harvested nodes to whole nodes of NL's plant was more than two times higher compared to KOR. The averaged daily global radiation during the whole growing periods was 14.5MJ/$m^2$/day in KOR and l2.1MJ/$m^2$/day in NL. Averaged 24h temperature was similar to both glasshouse as $21.6^{\circ}C$ in KOR and $21.2^{\circ}C$ in NL during the whole growing periods, however the variance was higher in KOR than NL. Humidity deficit (HD) was observed higher in KOR during the whole growing periods. Averaged day $CO_2$ concentration was measured contrary pattern in both countries because of heating to greenhouse on NL winter season. Averaged 24h temperature and day $CO_2$ concentration to daily global radiation was regular pattern in NL, whereas there are large scatter in KOR. Consequently, more irregular greenhouse climate condition in KOR could be induced irregularly crop growth.