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Abstract  

Hair samples from junior high school students in metropolitan areas of Taichung, Taiwan were tested for a total of 13 elements, Al, Ag, Br, Cl, Cr, Fe, K, La, Mn, Na, Sc, Se, and Zn by instrumental neutron activation analysis (INAA) to establish seasonal variations, gender and environmental exposures. The seasonal variations of hairs in 39 healthy students (18 males and 21 females; age 13.3 ± 0.4 years; height, 158.0 ± 4.1 cm; weight, 53.4 ± 5.7 kg) were collected at 1.5-month intervals for 1 year starting from late August, 2008. The concentrations of the above elements varied from 103 to 10−2 μg g−1 at different sampling times. A quantified index of agreement (AT) was introduced to help classify the elements. A smaller AT indicated highly consistent quantities of specific metals in the hair while a larger AT indicated increased fluctuation, i.e., less agreement. The different ATs in various hair samples were discussed. The concentrations of these elements are compared with the data in the literature.

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Abstract  

Over 90% of the cumene hydroperoxide (CHP) produced in the world is applied in the production of phenol and acetone. The additional applications were used as a catalyst, a curing agent, and as an initiator for polymerization. Many previous studies from open literature have verified and employed various aspects of the thermal decomposition and thermokinetics of CHP reactions. An isothermal microcalorimeter (thermal activity monitor III, TAM III), and a thermal dynamic calorimetry (differential scanning calorimetry, DSC) were used to resolve the exothermic behaviors, such as exothermic onset temperature (T 0), heat power, heat of decomposition (ΔH d), self-heating rate, peak temperature of reaction system, time to maximum rate (TMR), etc. Furthermore, Fourier transform infrared (FT-IR) spectrometry was used to analyze the CHP products with its derivatives at 150 °C. This study will assess and validate the thermal hazards of CHP and incompatible reactions of CHP mixed with its derivatives, such as acetonphenone (AP), and dimethylphenyl carbinol (DMPC), that are essential to process safety design.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: K. Inn, Zhichao Lin, Zhongyu Wu, C. McMahon, J. Filliben, P. Krey, M. Feiner, Chung-King Liu, R. Holloway, J. Harvey, I. Larsen, T. Beasley, C. Huh, S. Morton, D. McCurdy, P. Germain, J. Handl, M. Yamamoto, B. Warren, T. Bates, A. Holms, B. Harvey, D. Popplewell, M. Woods, S. Jerome, K. Odell, P. Young, and I. Croudace

Abstract  

In 1977, the Low-level Working Group of the International Committee on Radionuclide Metrology met in Boston, MA (USA) to define the characteristics of a new set of environmental radioactivity reference materials. These reference materials were to provide the radiochemist with the same analytical challenges faced when assaying environmental samples. It was decided that radionuclide bearing natural materials should be collected from sites where there had been sufficient time for natural processes to redistribute the various chemically different species of the radionuclides. Over the succeeding years, the National Institute of Standards and Technology (NIST), in cooperation with other highly experienced laboratories, certified and issued a number of these as low-level radioactivity Standard Reference Materials (SRMs) for fission and activation product and actinide concentrations. The experience of certifying these SRMs has given NIST the opportunity to compare radioanalytical methods and learn of their limitations. NIST convened an international workshop in 1994 to define the natural-matrix radionuclide SRM needs for ocean studies. The highest priorities proposed at the workshop were for sediment, shellfish, seaweed, fish flesh and water matrix SRMs certified for mBq per sample concentrations of 90 Sr, 137 Cs and 239 Pu + 240 Pu. The most recent low-level environmental radionuclide SRM issued by NIST, Ocean Sediment (SRM 4357) has certified and uncertified values for the following 22 radionuclides: 40 K, 90 Sr, 129 I, 137 Cs, 155 Eu, 210 Pb, 210 Po, 212 Pb, 214 Bi, 226 Ra, 228 Ra, 228 Th, 230 Th, 232 Th, 234 U, 235 U, 237 Np, 238 U, 238 Pu, 239 Pu + 240 Pu, and 241 Am. The uncertainties for a number of the certified radionuclides are non-symmetrical and relatively large because of the non-normal distribution of reported values. NIST is continuing its efforts to provide the ocean studies community with additional natural matrix radionuclide SRMs. The freeze-dried shellfish flesh matrix has been prepared and recently sent to participating laboratories for analysis and we anticipate receiving radioanalytical results in 2000. The research and development work at NIST produce well characterized SRMs that provide the world's environment-studies community with an important foundation component for radionuclide metrology.

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