KORAD (Korea Radioactive Waste Agency, http://www.korad.or.kr) has stored slightly contaminated ascon (asphalt coated concrete mixture) that was introduced to Gyeongju repository about a decade ago waiting for a final disposal. It is believed to be mainly contaminated by radioisotope 137Cs due to impurities introduced from the outside during the ascon manufacturing process. We studied characteristics of the radioactive waste to see whether this material would be proper enough to be disposed in Gyeongju LILW repository or be other ways to reduce the disposal volume including self-disposal before its final disposal otherwise. KORAD looked into the properness of characteristics of ascon in terms of WAC (Waste Acceptance Criteria) documented by KORAD that includes general chemical and physical properties of asphalt, density, size of grains, content of organic material and possibility of existence of chelate materials that qualitatively limited to be disposed by the criteria. And other associated characteristics such as gas generation and bio degradation were also investigated. Based on the data obtained from the study, we proposed various plausible solutions in associated with operational and disposal safety and economic view points. This study will be used for KORAD’s decision on how to control and safely dispose the spent ascon within a reasonable time period. And also those experiences may be applied for other LILW issues that require treatment or conditioning of radioactive wastes in the future.
The beneficial effect of silicon (Si) in increasing salt stress tolerance has been observed in many plants, including the cereal crops rice, wheat, and barley. In this experiment, we examined the effect of Si on the survival and growth of torenia (Torenia fournieri L inden ex F oum) ‘ Duchess Blue and White’ cultured in vitro in the presence and absence of salt stress. Previous reports had suggested that torenia exhibited low salt tolerance. Shoot buds isolated from 16-day-old seedlings were cultured on Murashige and Skoog (MS) medium containing 0, 50, or 100 mM NaCl alone or in combination with 1.8 or 3.6 mM Si supplied as K2SiO3. Plant survival rate was significantly reduced by NaCl supplementation compared with the control. The survival rate significantly increased to 100% when 1.8 or 3.6 mM Si was added to the MS medium containing 50 mM NaCl. However, only 31% of plantlets survived when 1.8 mM Si was added to the culture medium containing 100 mM NaCl. Shoot and root lengths significantly decreased with increasing NaCl concentration in the culture medium, whereas addition of NaCl to the MS medium also significantly reduced fresh and dry weights. However, Si supplementation significantly increased fresh and dry weights under 50 mM NaCl, compared with the control. The greatest fresh and dry weights were recorded when shoot buds were cultured on MS medium containing 50 mM NaCl and 3.6 mM Si. The activities of the antioxidant-scavenging enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), but not peroxidase (POD), were markedly higher in the presence of 50 mM NaCl than the activity of the control. When Si was added to the medium containing 50 mM NaCl, activities of SOD, POD, APX, and CAT decreased as compared with the 50 mM NaCl treatment. Thus, Si-mediated tolerance to NaCl stress was not due to increased activity of antioxidant enzymes. Although Si was not effective in increasing tolerance to high salt concentrations, such as 100 mM NaCl, the results suggested that Si supplementation could effectively enhance tolerance to 50 mM NaCl stress.
The effects of temperature (150°C and 160°C) on physicochemical properties of extruded texturized vegetable protein with mealworm (0%, 15%) were studied. The extrusion process had a screw speed of 250 rpm, moisture content of 65%. The variation of formula was gluten content of 40% in 4 samples and none of gluten in 4 samples. As addition of mealworm increased and temperature increased, breaking strength and integrity index decreased, The nitrogen solubility index and protein digestibility increased as addition of mealworm increased and temperature decreased. DPPH radical scavenging activity significantly increased as addition of mealworm increased and temperature increased. On the contrary, the value of rancidity decreased as addition of mealworm increased even in 60 days. In conclusion, addition of mealworm became softer texture, and protein quality of the extruded texturized vegetable protein. The process promoting functionality such as improvement of antioxidant function was confirmed through this study. Also, adjusting temperature have an effect on protein content and antioxidation. The addition of gluten of 40% resulted in improving texture of TVP.