• Journal of Biosystems Engineering
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• 제40권3호
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• pp.224-231
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• 2015

Purpose: Corn is a major commercial crop targeted for genetic modification owing to its high consumer demand as a foodstuff for humans and livestock, as well as its other industrial applications. However, the safety of genetically modified (GM) crops is controversial. Indeed, several countries have banned the importation of GM seeds that can germinate. Therefore, development of effective, convenient, and nondestructive methods to inhibit seed germination is required. Methods: This study aimed to examine the efficacy of microwave heat treatment for inhibition of germination of corn kernels and for optimization of power and exposure time required for effective aging treatment. Artificial inhibition was induced in corn kernels using microwave heat treatment. Seven power levels were examined (400, 500, 600, 700, 800, 900, and 1000 W) at each of the four exposure times (0.5, 1.0, 1.5, and 2.0 min). Results: Corn kernels could be aged effectively after heating for 0.5~1.0 min at powers greater than 800 W, with increasing efficacy observed at higher powers. Further analysis showed that the most effective inhibition of germination was observed at 1000 W for 40 s. This setting did not cause any physical damage to the corn kernels. Conclusions: Optimal inhibition of corn kernel germination was achieved using higher power for shorter times, which may be useful for industrial corn seed treatment.

• 한국농공학회지
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• 제24권4호
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• pp.92-98
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• 1982

The major objective of this study was to investigate the heat resistance of epoxy resin mortar. For this purpose, these tests of compressive and bending strength were accomp- olished with various heating temperature (40˚C, 60˚C, 80˚C, 100˚C, 120˚C), and with various mixing ratio (1: 2, 1: 4, 1: 6, 1: 8, 1:10, 1:12, 1:14). The exprimental resin was to be Epi-Bis type epoxy resin, which is widely used as construction materials. The results obtained are summarized as follows; 1. The variations of color tone started to begin at 60˚C, and it has come out very heavy at 120˚C. It was assumed that the decrement of weight resulted from carbonization were about 0.22% at 100˚C, and about 0.34% at 120˚C. 2. The compressive and bending strength were increased with temperature rise up to 80˚C, but these were made rapid decrease when the given temperature was over. And so, the mean decrement of compressive and bending strength at 120˚C reached up to 35.5% and 26.4%, respectively. 3. The regression equation between compressive and bending strength for epoxy resin mortar under heat exposure were obtained as follows; od=0. 371oc+39. 23 (r=0. 986) And the estimated value of bending strength was corresponded to about 37 percent in comparing with that of the compressive strength. 4. Consquently, the heat resistance temperature of epoxy resin mortar was to be around 80˚C, and it was generally very low values. But it was regarded that the epoxy resin mortar will not be difficult with materials of civil engineering works and agricultural structures.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권4호
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• pp.261-266
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• 2004

Hyperthermia (HT) in combination with anticancer drugs (ACDs) had proven to more efficacious in various cancers, although efficacies vary according to chemotherapeutic compounds and cancer types. Presently there are few data that compares anticancer efficacies among ACDs under hyperthermic conditions. Therefore, we selected three commonly used ACDs (quercetin, verapamil and doxorubicin) and compared their antitumor effects when each was treated with 43$^{\circ}C$ HT exposure. Firstly, FM3A, a murine breast cancer cell line, was treated with each ACD for 1 h followed by 43$^{\circ}C$ exposure for additional 1 h, and examined the effects of: 1) each drug, 2) 43$^{\circ}C$ HT exposure, and 3) the combination of each drug and 43$^{\circ}C$ HT exposure for 1, 6 and 24 h. The determined overall effects on FM3A cells were arrested cell proliferation, clonogenic efficiency and apoptosis. Pre-treatment of FM3A cells to each ACD followed by 43$^{\circ}C$ HT exposure produced greater antitumor effects including suppressed cell proliferation, reduced clonogenic efficiency and increased apoptotic cell death, compared to ACD treatment or HT exposure alone. Apoptotic cell death occurred in a time-dependent manner. Among the ACDs, antitumor efficacies varied in the order of doxorubicin > verapamil > quercetin. It was concluded that heat exposure during ACD treatment of caner cells may be an important factor to get a better antitumor benefit, even though this benefit may differ from one drug to another.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.18.2-18.2
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• 2005

• Safety and Health at Work
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• 제4권4호
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• pp.216-220
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• 2013

A 46-year-old man who had worked as a bumper spray painter in an automobile body shop for 15 years developed lung cancer. The patient was a nonsmoker with no family history of lung cancer. To determine whether the cancer was related to his work environment, we assessed the level of exposure to carcinogens during spray painting, sanding, and heat treatment. The results showed that spray painting with yellow paint increased the concentration of hexavalent chromium in the air to as much as $118.33{\mu}g/m^3$. Analysis of the paint bulk materials showed that hexavalent chromium was mostly found in the form of lead chromate. Interestingly, strontium chromate was also detected, and the concentration of strontium chromate increased in line with the brightness of the yellow color. Some paints contained about 1% crystalline silica in the form of quartz.

• Composites Research
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• 제27권6호
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• pp.236-241
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• 2014

본 연구에서는 공항 포장용 유지보수 재료로 사용되는 폴리머 콘크리트의 자외선 노출에 대한 기계적 물성 변화를 확인하기 위해 자외선 노출 전/후 시편의 압축강도 및 연성인자의 변화를 평가하였다. 현재 공항 포장용으로 사용되는 폴리머 콘크리트의 비율과 선행연구를 통해 얻은 최적 배합비율을 참고하여 시편을 제작하였다. 자외선 발생 램프의 출력을 고려하여 자연상태에서 노출되는 등가시간을 계산한 후 최대 3년에 해당하는 시간만큼의 등가시간 동안 시편을 노출시켰다. 실험결과, 자외선 노출 자체는 재료물성에 거의 영향을 주지 않았으며, 자외선 노출에 따른 온도상승에 의한 재료물성 변화가 주로 관찰되었다. 자외선에 의해 발생된 열에 노출된 후 모든 시편에서 인성은 감소하고, 압축강도는 증가하는 경향을 나타내었다.

• 한국세라믹학회지
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• 제45권6호
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• pp.345-349
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• 2008

$TiO_2$ coating ceramic tile for self-cleaning purpose was prepared by the precipitant dropping method using $TiCl_4$ as a precursor. $TiO_2$ film was formed on the ceramic tile by spray-coating technique and heat-treated at $500^{\circ}C$ for 1 h. The size and crystalline structure of $TiO_2$ particles were 15.3 nm and anatase phase. The outdoor exposure tests were conducted and the effects of outdoor exposure test conditions, such as exhaust concentration of contamination materials (test places), the UV light intensity (irradiation direction) and coating amounts of $TiO_2$ on the self-cleaning properties were investigated by the brightness measurements. As a results, self-cleaning property of $TiO_2$ coating tile was affected by the coating amount of $TiO_2$ however, not affected by the UV light intensity included in sun's ray (irradiation direction). $TiO_2$ coating ceramic tile can be utilized for exterior finishing materials because of self-cleaning property of $TiO_2$ coating tile.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.270-277
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• 2023

Exposure to ionizing radiation induces free radicals in human nails. These free radicals generate a radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Compared with the RIS of tooth enamel samples, that in human nails is more affected by moisture and heat, but has the advantages of being sensitive to radiation and easy to collect. The fingernail as a biological sample is applicable in retrospective dosimetry in cases of localized hand exposure accidents. In this study, the dosimetric characteristics of fingernails were analyzed in fingernail clippings collected from Korean donors. The dose response, fading of radiation-induced and mechanically induced signals, treatment method for evaluation of background signal, minimum detectable dose, and minimum detectable mass were investigated to propose a fingernail-EPR dosimetry protocol. In addition, to validate the practicality of the protocol, blind and field experiments were performed in the laboratory and a non-destructive testing facility. The relative biases in the dose assessment result of the blind and field experiments were 8.43% and 21.68% on average between the reference and reconstructed doses. The results of this study suggest that fingernail-EPR dosimetry can be a useful method for the application of retrospective dosimetry in cases of radiological accidents.

• 한국산업보건학회지
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• 제17권1호
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• pp.71-80
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• 2007

The purpose of this study was to assess the ambient level of Polynuclear aromatic hydrocarbons(PAHs), oil mist of the metalworking fluids(MWFs), especially in heat treat industry and non heat treat industry. And we assessed the relationship of the pattern of exposed PAHs with oil mist during survey day. The study population of heat treat industries contained 98 workers, non-heat treat industry contained 40 workers. Personal samples were taken for ambient monitoring of PAHs and oil mist. PAHs was to analyze the relationship of airborne oil mist. The geometric mean of airborne total PAHs was $3.44{\mu}g/m^3$ in heat treat industry and $0.13{\mu}g/m^3$ in non heat treat industry, Pyrene and Benzo(a)pyrene was detected from heat treat industry and Naphthalene in heat treat industry was significantly detected higher than in non heat treat industry. The geometric mean of airborne oil mist was $0.19{\mu}g/m^3$ in heat treat industry and $0.70{\mu}g/m^3$ in non-heat treat industry. The correlation between oil mist and total PAHs was shown below, total PAHs in workers of non heat treat industry and heat treat industry were not significantly correlated with oil mist

• 한국자동차공학회논문집
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• 제17권4호
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• pp.126-132
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• 2009

Automotive heat exchangers use louver fins for their high efficiency. However, the efficiency can significantly drop for constructional vehicles or heavy equipments due to dust deposited on the louver fins with narrow slits. Thus it is necessary to develop new fins that lead to less fouling, so that a better performance can be achieved after exposure to a dusty environment over long period of time. New wavy fins were considered in the study and numerically analysed to compare with louver fins in the areas of air-side pressure drop, heat release rate, and particulate deposition. In addition, an experiment was done on the pressure drop and the particulate deposition. The results showed that the wavy fins would be a better choice for long-term use due to the excellent dust-proof performance in comparison to louver fins, in spite of the initial inferior performance of heat release.