Investigations of nitrogen content and thermal decomposition activation energy (Ea) of two different kinds of nitrocellulose (NC) products, NMNC and MNC from the non-fat and original processes of linters,
respectively, were discussed. In this study, differential scanning calorimetry (DSC) and element analyzer (EA) are used, for
the above two chemicals, along with the same nitration condition in use of sulfuric acid (H2SO4) and nitric acid (HNO3) mixing acid. Ea was calculated by our induced model. According to our experimental results, the nitrogen content of NMNC/MNC was 11.71 and
11.55 mass%, in a low nitrogen content condition of mixing acid. The Ea parameters were 319.91 (NMNC) and 347.27 (MNC) kJ mol−1, individually. They indicated that the non-fat process of a linter made a higher degree of stability than the others. This
research also presents an efficient and accurate model of the thermal decomposition property evaluation for non-fat process
of linters. The outcome is believed to be very useful for helping to understand, and be applied as, an inherently safer design
during relevant NC manufacturing processes.
A comprehensive analysis of routine radiochemistry data obtained at a BWR plant has been performed. The variation of fission product release levels as well as the characteristics of the release pattern were evaluated. The number of defective fuel bundles and the exposures of the defective fuel are correctly predicted from the results of data analyses.
Authors:M. Lin, N. Lin, C. Chen, H. Liaw, and C. Shu
Explosion limits are crucial information for people who handle/operate flammable vapors or gases. It was reported in our previous
studies that there is a theoretical linear relation between the reciprocal of the explosion limits and the reciprocal of the
molar fraction of hydrocarbons diluted with inert carbon dioxide or nitrogen. In this work, oxygenated hydrocarbons were inertized
by inert steam, and the relation of the upper explosion limit and the extent of the inertization was explored. With the assumption
that the adiabatic flame temperatures are the same for all limit mixtures, it was found that the aforementioned linear relation
still holds in case the inert gas is of steam and the flammable material is of oxygenated hydrocarbons. Experimental work
was carried out in a 20-L-Apparatus at 101 kPa and 423 K to measure the upper explosion limit of methyl alcohol, acetone,
and methyl formate diluted with steam, respectively. It was found that experimental results fit the theoretical model very
Authors:C. Lin, Y. Chang, J. Lee, S. Lin, and C. Shu
Preventing accidental explosions of flammable liquid/gas mixtures is very important. As far as flammability characteristics
are concerned, we simulated the effects of inert liquid/gas, which was filled with reactors, vessels, or closed space, employed
in the chemical process industries. The inert liquid/gas (H2O) weakened the oxygen concentration and reduced solvent vapor concentration in a 20-L-Apparatus. This study investigated
the flammability characteristics of acetone/water solutions (100/0, 75/25, 50/50, and 25/75 vol.%) that are controlled at
a temperature of 150°C and pressures of 101/202 kPa, respectively. The flammability parameters included flammability limits
(LEL and UEL), maximum explosion pressure (Pmax), maximum explosion pressure rise ((dP dt−1)max), and vapor deflagration index (Kg). The results of a series of experimental tests showed that UEL, Pmax, and Kg all decreased with steam rising under the experimental conditions. The results can be applied to process safety design/operation
for identifying whether the inert liquid/gas (H2O) content has any substantial effects in reducing the fire and explosion hazard of the solution of interest.
A rapid adsorption method has been developed to determine the60Co content in sea water samples. The60Co activity is concentrated by filtering the water sample through an adsorption column of steel work. A 60-liter sample can be processed in 1 h with 95% adsorption efficiency.
Authors:C. Chung, C. Chen, C. Lin, W. Yeh, and C. Lee
Rapid, in situ measurements were used for quantitative monitoring of gaseous fission products around the nuclear power stations
in Taiwan. A portable high-resolution germanium detector with portable multichannel analyzer was used in the field monitoring
work. The detecting unit was calibrated using activated Ar, Kr, and Xe isotopes dispersed in a large chamber to obtain absolute
efficiency curve in terms of γ-counts per m3 versus gamma-ray energy. The calibrated detecting unit was brought to the nuclear power plants for in situ monitoring for
both normal operation and nuclear accidental exercise. In a typical four-hour measurement, the detection limits for most Kr
and Xe fission product isotopes were 0.0028%≈0.98% of the derived air concentration (DAC) imposed by the local authority.
The dose rate caused by gaseous radioisotopes released from nuclear power stations and dispersed to the surroundings can be
quantitatively monitored in a short period using this portable unit.
Authors:S. Lin, J. Tseng, Y. Lin, W. Huang, and C. Shu
The polymerization mechanisms of styrene and various derivatives by α-methylstyrene (AMS) and trans-β-methylstyrene (TBMS) were evaluated. Experiments were carried out for dimerization identification and thermal polymerization
estimation by differential scanning calorimetry (DSC), thermal activity monitor (TAM) and Fourier transform infrared absorption
spectrophotometer (FTIR). The results show that, under temperature ranges of 60–190 and 50–170°C, AMS and TBMS performed dimerization
by benzene ring and ethylene double bond, respectively. AMS and TBMS would form unsaturated dimers, saturated dimers and trimers,
etc., during the period of thermal polymerization. Through this study, one can estimate possible intermediates of the polymerization
process for the monomer of interest in the petrochemical industry.
Authors:S. Yeh, C. Lin, C. Tsai, H. Yang, and C. Ke
An attempt was made to establish a reliable method using chemical neutron activation analysis for surveillance of pollutants in waste waters released by plants manufacturing various kinds of products. Since preconcentration process played important role in the entire course of the analysis work, special precaution was taken to re-confirm that the recovery efficiencies for pollutant ions were satisfactory during the preconcentration. It was also re-examined that the Langmuir's adsorption isotherm pattern well obeyed by all ions under investigation. In recent years, significant amounts of rare earth compounds and other raw materials containing representative elements have been imported and consumed to meet the demand due to the rapid progress in new manufacturing technology. Samples were collected from ten various production lines in plants and potential pollutants were determined using the Tsing Hua Open-pool Reactor. It would be noteworthy that the specimens obtained by this preconcentration process also would be usable for Induced Coupled Plasma-Mass Spectrometry analysis for supplementary and/or comparison purposes.
Authors:S. Lin, C. Chiang, C. Huang, C. Tseng, and M. Yang
Five kinds of urinary stones from 42 patients have been determined for a total of 19 elements by instrumental neutron activation analysis. Of these elements, Ca, Mg, Sr, Na, and Cl are found to be present in the core of all kinds of stones. The differences in elemental composition among the different kinds of stones as well as across the layers of stone are statistically evaluated.
Information about the kinetics and thermal
decomposition of hydrogen peroxide (H2O2)
has been required for safety reasons, due to its broad applications in many
chemical industries. To determine the inherent hazards during H2O2
manufacturing, transportation, disposal, usage, and so on, this study deliberately
selected various H2O2 concentrations
and analyzed them by differential scanning calorimetry (DSC). In addition,
thermokinetic parameters were not only established for each of these reactions,
but also aimed at comprehensive, kinetic models with various tests conducted
at different heating rates.
To build up a comprehensive kinetic
model, various tests were conducted by heating rates of 1, 2, 4, 10C
min–1, respectively. According to dynamic
DSC tests, the experimental curves show that H2O2
decomposition has one exothermic peak and may start to decompose under 47–81C.
The total heat of decomposition is about 192–1079 J g–1.
Not only can these results prevent accidents caused by H2O2
during storage and transportation, but also assess its inherent hazards and
thereby design procedures for emergency response while runaway reactions occurring.