The purpose of this study was to conduct a thermal analysis of the hydrolysis and degradation behavior of biodegradable polymers
and bio-composites at 50°C and 90% relative humidity (RH). With increasing hydrolysis time, the thermal stability and degradation
temperature of polybutylene succinate (PBS) slightly decreased. The glass transition temperature (Tg) and melting temperature (Tm) of PBS and the anti-hydrolysis agent treated PBS did not vary significantly with increasing hydrolysis time, whereas those
of the trimethylolpropane triacrylate (TMPTA)-treated PBS slightly increased. With increasing hydrolysis time, the storage
modulus (E’) values of the bio-composites decreased, whereas those of the TMPTA treated bio-composites slightly increased. Also, the
tan values of the anti-hydrolysis agent and TMPTA treated PBS-BF bio-composites were slightly lower than those of the non-treated
bio-composites, due to the reduction in their degree of hydrolysis. The tanδmax peak temperature (Tg) of the anti-hydrolysis agent treated bio-composites was not significantly changed, whereas that of the TMPTA treated bio-composites
The effects of red grape, wild grape and black raspberry wines on the quality of ground pork during a 15 days refrigerated storage period were investigated. The levels of phenolic compounds were the highest in black raspberry wine (P<0.05). In contrast, the antioxidant capacities according to ferric reducing antioxidant potential (FRAP) and trolox equivalent antioxidant capacity (TEAC) were not significantly different among the wines (P>0.05). The addition of 5% and 10% wine influenced the quality of ground pork by decreasing pH, inhibiting the progression of lipid oxidation and the formation of total volatile basic nitrogen (TVB-N), and stabilizing the red colour of the ground pork compared to control samples to which no wine was added. In ground pork, addition of red grape wine led to lower concentrations of thiobarbituric acid reactive substances (TBARS, 0.19–0.39 mg kg−1) and TVB-N values (69.1–119.9 mg kg−1) than wild grape (0.16–0.43 mg kg−1 and 72.0–194.1 mg kg−1, respectively) or black raspberry wine (0.33–0.58 mg kg−1 and 81.7–225.4 mg kg−1, respectively) up to 10 days of storage. Results from the present study suggested that the quality of ground pork was affected by wine type and storage period. These effects could be due to phenolic compounds as well as other chemical components of the wines.
Authors:H. Eun, Y. Cho, H. Park, I. Kim, and H. Lee
In this paper, a separation method of radionuclides (Ba, Sr) from LiCl salt wastes generated from the electroreduction process
of spent nuclear fuel was studied to recover pure LiCl salts and reduce radioactive wastes. The method consisted of chemical
conversion process of BaCl2 and SrCl2 in LiCl molten salts by using lithium compounds and vacuum distillation process of LiCl salts. In the chemical conversion,
BaCl2 and SrCl2 in LiCl molten salts were mainly converted into (Ba,Sr)CO3 or (Ba,Sr)SO4. Contents of Ba and Sr in LiCl salts recovered from the vacuum distillation process were equal to about 0.01 of initial concentrations
of Ba and Sr in LiCl molten salts. These results will be utilized to recycle the LiCl salt wastes.
This paper is a study on a stable destruction method of radioactive waste ion exchange resins. According to the resin TGA
results, its decomposition occurred through three stages. And a sufficient retention time of the resins and an effective retention
capacity of SO2 gases and the doped metal compounds were required to destruct resins doped with radioactive metals stably. The resins doped
with radioactive metal surrogates were effectively destructed in the lab-scale MCO system. CO and SO2 emissions were below 100 and 1 ppm, respectively. And the surrogates were collected more than 99.9% in the molten carbonate.
Thus, the resins can be destructed stably in the MCO process.
The determination of the hydrogen concentrations in coal and metal samples were investigated by using the PGAA system at the
HANARO Research Reactor, KAERI. The calibration curve of the hydrogen concentration was obtained from a standard sample and
the effects of the interference peaks near the gamma-energy region of hydrogen were investigated. The background in the hydrogen
peak of a prompt gamma-ray spectrum was measured for the sample chamber and shielding materials of an atmospheric state. The
combined uncertainties estimated for the analysis procedure were in the range of 4–5%. Two kinds of certified reference materials,
NIST SRM 1632c (Coal), NIST SRM 173c (Titaniumbase Alloy) and NIST SRM 2453 (Titanium Alloy) were used to verify the accuracy
and precision of the measurement. The relative error was in the range of 3–6% and the relative standard deviation were less
Authors:H. Cho, K. Chun, K. Park, Y. Chung, and H. Kim
In the boron neutron capture therapy, an accurate determination of the boron content in a biological sample is very important.
The boron content was investigated with a standard solution of boron which was administered intraperitoneally with a dose
of 750 mg/kg body weight into mice induced cancer cells and tumors. The boron content for two types of a sample was compared
to the boronophenylalanine for the tumor and the ethylamine derivatives for the induced cancer cell, which were also investigated
for their accumulation rate in each organ such as blood, spleen, liver, kidney and brain. An analytical quality control was
carried out by using certified reference materials such as Peach Leaves, Apple Leaves and Spinach Leaves. The relative error
of the measured values was in good agreement within 2% to the certified values.
Authors:E. Park, H. Jo, H. Kim, K. Cho, and J. Jung
In order to reduce the toxicity of both raw wastewater and effluent from a rubber products factory, γ-ray treatment was applied
at different dose levels. The γ-ray treatment did not completely removed the toxicity, suggesting that there were major toxicants
other than destroyable organic compounds. Toxicity identification evaluation (TIE phase 1) was conducted to characterize major
toxicants using Daphnia magna. The suspected toxicants in both raw wastewater and effluent were mostly filterable materials and EDTA chelatable metals
and, to some degree, non-polar organic compounds. Anion-exchange removable compounds, most likely organics, were found only
in raw wastewater. Metal analyses showed that zinc and copper concentrations were above levels causing toxicity to D. magna. After 20 kGy γ-ray treatment of raw wastewater, filtrations both at pH 3 and at the initial pH (pH 3.6) showed dramatic
change (9 to 77% and 29 to 85%, respectively) in toxicity reduction, suggesting the formation of toxic filterable materials
which are stable even at acidic conditions. Unlike raw wastewater, there was no significant change in TIE results after γ-ray
treatment at 20 kGy for rubber effluent.
Authors:H. Yang, Y. Cho, H. Eun, E. Kim, and I. Kim
Kinetics of a thermal dechlorination and oxidation of gadolinium oxychloride (GdOCl) originating from a molten salt process
was investigated under various oxygen partial pressures by using a non-isothermal thermogravimetric (TG) analysis. The results
of isoconversional analysis of the TG data suggests that the dechlorination and oxidation of GdOCl follows a single step reaction
and the observed activation energy was determined as 137.7�4.1 kJ mol−1. The kinetic rate equation was derived for a conversion of the GdOCl with a linear-contacting boundary reaction model. The
power dependency for oxygen and the pre-exponential factor was determined as 0.306 and 1.012 s−1 Pa−0.306, respectively.
Authors:H. Kim, S. Choi, B. Lee, S. Kim, C. Cho, and D. Cho
In this study, the thermal properties of bio-flour-filled, polypropylene (PP) bio-composites with different pozzolan contents
were investigated. With increasing pozzolan content, the thermal stability, 5% mass loss temperature and derivative thermogravimetric
curve (DTGmax) temperatures of the bio-composites slightly increased. The coefficient of thermal expansion (CTE) and thermal expansion
of the bio-composites decreased as the pozzolan content increased. The glass transition temperature (Tg), melting temperature (Tm) and percentage of crystallinity (Xc) of the bio-composites were not significantly changed. The thermal stability, thermal expansion and Xc of the maleic anhydride-grafted PP (MAPP)-treated bio-composites were much higher than those of non-treated bio-composites
at 1% pozzolan content due to enhanced interfacial adhesion. X-ray diffraction (XRD) analysis confirmed the crystallinity
of pozzolan-added bio-composites. From these results, we concluded that the addition of pozzolan in the bio-composites was
an effective method for enhancing the thermal stability and thermal expansion.