• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2004.11a
• /
• pp.200-200
• /
• 2004

• Korean Journal of Materials Research
• /
• v.22 no.2
• /
• pp.91-96
• /
• 2012

AC and ZnS modified $TiO_2$ composites (AC/ZnS/$TiO_2$) were prepared using a sol-gel method. The composite obtained was characterized by Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, scanning electron microscope (SEM) analysis, and according to the UV-vis absorption spectra (UV-vis). XRD patterns of the composites showed that the AC/ZnS/$TiO_2$ composites contain a typical single and clear anatase phase. The surface properties as observed by SEM present the characterization of the texture of the AC/ZnS/$TiO_2$ composites, showing a homogenous composition in the particles showing the micro-surface structures and morphology of the composites. The EDX spectra of the elemental identification showed the presence of C and Ti with Zn and S peaks for the AC/ZnS/$TiO_2$ composite. UV-vis patterns of the composites showed that these composites had greater photocatalytic activity under visible light irradiation. A rhodamine B (Rh.B) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of Rh.B was determined using UV/Vis spectrophotometry. An increase in the photocatalytic activity was observed. From the photocatalytic results, the excellent activity of the Y-fullerene/$TiO_2$ composites for the degradation of methylene blue under visible irradiation could be attributed to an increase in the photo-absorption effect caused by the ZnS and to the cooperative effect of the AC.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.6
• /
• pp.1025-1029
• /
• 2000

This study was conducted to investigate whether a DNA comet assay could be applied for identifying irradiated pork and beef. Pork and beef were irradiated with Co-60 gamma rays at 0.1, 0.3, 0.5, 0.7 and 1.0 kGy, and stored in a freezer Cells separated from the samples were embedded in agarose gel on a slide, dissolved in a lysis solution, and electrophoresed at 2 V/cm for 2.0 min by horizontal electrophoesis. The cells were then stained with a silver staining in order to visualize the DNA using a micro-scope. The DNA fragments of the irradiated cells stretched or migrated out of the cells and formed tails towards the anode, giving the appearance of comets, while unirradiated cells formed very short or no tails. The distance of DNA migration increased with irradiation dose. Since the statistical analysis showed a significant correlation between tail length and irradiation dose, a DNA comet assay could provide not only identification but also estimation of the irradiation dose for irradiated beef and pork.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.1
• /
• pp.1-10
• /
• 2013

The exposure of food to ionizing radiation has been recognized as a safe and effective mode of food preservation in more than 55 countries. The benefits include eradication of insect pests, inactivation of food pathogens, extension of shelf-life, and improvement in food hygiene. Regulatory authorities around the world have emphasized the implementation of various national and international regulations to facilitate trade and development of consumers' confidence in purchasing irradiated foods. Therefore, the need for reliable irradiation detection methods has increased to enforce these regulations. At present, a number of promising analytical approaches have been developed and evaluated. Moreover, about 10 European Standards have been adopted as General CODEX Alimentarius methods for the detection of irradiated foodstuffs. However, most of these methods demand relatively expensive equipment and prolonged sample preparation. Therefore, simple and cost-effective approaches would be advantageous for rapid screening of foodstuffs. The suspected samples need to be analyzed further with more validated techniques to confirm the screening results. In this review, existing screening methods (i.e. physical, chemical, and biological) for the identification of irradiated foods have been outlined along with their principles, scopes and limitations.

• Microbiology and Biotechnology Letters
• /
• v.47 no.3
• /
• pp.381-389
• /
• 2019

Chlorella vulgaris was isolated from the Nile River, Qalubia Governorate, Egypt, for possible use in biodiesel production. BG-II nutrient growth media was used for isolation and laboratory growth. Identification was performed via 18S rRNA gene amplification, followed by sequencing. The alga was exposed to UV-C (254 nm) for 15, 30, and 45 s to improve dry weight accumulation and to increase the oil production. Daily measurements of dry weight ($g{\cdot}l^{-1}$) were performed; oil content and volumetric lipid productivity were also determined. UV-C exposure led to an increase in the volumetric lipid productivity by 27, 27.3, and $32.4mg{\cdot}l^{-1}{\cdot}d^{-1}$ with 15, 30, and 45 s, respectively, as compared with the control, which resulted in $18mg{\cdot}l^{-1}{\cdot}d^{-1}$. Of the examined mutants, the one with the highest productivity was re-irradiated by UV-C (254 nm) for 15, 30, 45, and 60 s. For 15 s of exposure time, the oil content increased to 34%, while it was 31% at 30 s; further, it decreased to 22% at 45 and 60 s exposures. The fatty acid methyl ester profile was 82.22% in the first mutant at 45 s, compared with the wild strain that contained a total of 66.01% of FAs. Furthermore, the highest levels of polyunsaturated fatty acid methyl ester were observed in the mutant exposed for 45 s, and it reached 11.41%, which reduced the cetane number to 71.3.

• Applied Biological Chemistry
• /
• v.18 no.1
• /
• pp.10-15
• /
• 1975

These studies were conducted to induce the available mutants in Takju yeasts by the irradiation of UV light. Two original strains(5-Y-5, 6-Y-6) using for irradiation of UV selected from 24 strains which were isolated from the Takju mashes And Nuruks collected from 12 local regions of Chungnam and Chungbuk provinces in Korea, and the irradiations to the yeasts with UV light were carried out at a distance 10-40cm from the sources of irradiation for 10-220 seconds. The purpose of this experiment is to report the effects of irradiating distances and times of UV light on the survival ratio of orginal yeasts, and the identification of two orginal yeasts and three mutants induced by the irradiation of UV light. The results were summarized as follows. 1) The effects of irradiating distances and times on the survival ratio on the yeasts were represented as follows. and acid productivity to the survival strains by the irradiation of UV light. The selected mutants were the strains 30-24, 40-27 which have more powerful fermentability about 10 percent than those of original strains and a strain 30-81 which have potential acid productivity. 3) The selected yeasts (5-Y-5, 6-Y-6) were identified to Saccharomyces cerevisiae by a taxonomic study of Lodder and the mutants(30-81, 40-27, 30-81) induced from above yeasts by the irradiation of UV light have almost same properties two orginal yeasts in the identical characteristics.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.6
• /
• pp.1050-1056
• /
• 2000

To identify the irradiation-induced volatile flavor compounds, which were not detected in unirradiated sample and had positive correlation with the increment of irradiation dose, the volatile flavor compounds of irradiated (0, 1, 3, 5, 10 kGy) chicken were analyzed by liquid liquid continuous extraction (LLCE) and gas ehromatographyimass spectrometry (GC/MS) methods. One hundred twenty nine compounds were detected in irradiated chicken, and these compounds were composed mainly of hydrocarbons (62 compounds), aromatic compounds (44), aldehydes (9), ketones (5) and miscellaneous compounds (10). Among these, only 3 volatile compounds including 2-methylpentanal (r=0.24), 4-methylcyclohexene (r=0.08) and cyclotetradecene (r=0.92), were detected as irradiation-induced volatile flavor compounds in irradiated chicken. However, only cyclotetradecene was selected as a marker compound for detecting irradiation dosages with high correlation coefficient in irradiated chicken.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.6
• /
• pp.1042-1049
• /
• 2000

Irradiation-induced volatile flavor compounds in irradiated (1, 3, 5, 10 kGy) beef were analyzed by liquid liquid continuous extraction (LLCE) and gas chromatography/mass spectrometry (GC/MS) methods. One hundred fifty volatile compounds were detected in irradiated beef. These compounds were composed mainly of 71 hydrocarbons, 35 aromatic compounds, 15 aldehydes, 7 ketones, 4 acids, 6 esters and 12 miscellaneous compounds. Among these, only 6 volatile compounds including (E) -2-hexenal, nonene, 2-nonenal, cyclodecene, dodecene and cyclododecene were detected as irradiation-induced volatile flavor compounds, comparing with unirradiated beef meat. However, 4 volatile compounds, such as cyclodecene (r=0.88), (E)-2-hexenal (r=0.85), nonene (r=0.74) and 2-nonenal (r=0.70), having a positive correlation coefficient with the increment of irradiation dose, were considered as marker compounds for detecting irradiation dosages in irradiated beef.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.2
• /
• pp.236-242
• /
• 2005

To develop a new detection method using irradiation-induced volatile marker compounds of red pepper powder (RP), the volatile compounds of irradiated RP (0, 1, 3, 5, and 10 kGy) were analyzed by purge and trap (P&T)/solid phase microextraction (SPME)/gas chromatography/mass spectrometry (GC/MS) methods. A total of 51 and 31 compounds were detected in IRP by SPME and P&T methods, respectively. Among these, 25 compounds, which were composed of 4 hydrocarbons, 7 aldehydes, 1 ketone, 3 alcohols, 4 aromatic compounds, 2 esters and 4 miscellaneous compounds, showed irradiation dependent manner with significant positive correlation (p<0.01 or p<0.05) between irradiation dose and relative concentration. However, all compounds except 1,3-bis(1,1-dimethylethyl)benzene were not suitable as marker compounds because of their low determination coefficients ($R^2$<0.80) between irradiation dose and their concentrations, and detectablilty in nonirradiated sample. Therefore, only one compound, 1,3-bis(1,1-dimethylethyl)benzene, was tentatively identified as a volatile marker compound to detect irradiated RP.

• Nuclear Engineering and Technology
• /
• v.53 no.10
• /
• pp.3367-3378
• /
• 2021

The design phase and safety assessment of Generation IV liquid metal-cooled fast reactors calls for the improvement of fuel pin performance codes, in particular the enhancement of their predictive capabilities towards uranium-plutonium mixed oxide fuels and stainless-steel cladding under irradiation in fast reactor environments. To this end, the current capabilities of fuel performance codes must be critically assessed against experimental data from available irradiation experiments. This work is devoted to the assessment of three European fuel performance codes, namely GERMINAL, MACROS and TRANSURANUS, against the irradiation of two fuel pins selected from the SUPERFACT-1 experimental campaign. The pins are characterized by a low enrichment (~ 2 wt.%) of minor actinides (neptunium and americium) in the fuel, and by plutonium content and cladding material in line with design choices envisaged for liquid metal-cooled Generation IV reactor fuels. The predictions of the codes are compared to several experimental measurements, allowing the identification of the current code capabilities in predicting fuel restructuring, cladding deformation, redistribution of actinides and volatile fission products. The integral assessment against experimental data is complemented by a code-to-code benchmark focused on the evolution of quantities of engineering interest over time. The benchmark analysis points out the differences in the code predictions of fuel central temperature, fuel-cladding gap width, cladding outer radius, pin internal pressure and fission gas release and suggests potential modelling development paths towards an improved description of the fuel pin behaviour in fast reactor irradiation conditions.