The thermotropic phase transitions in the perovskite type layer compound (n-C10H21NH3)2MnCl4 and (n-C14H29NH3)2MnCl4 were synthesized and, at the same time, a series of their mixtures C10Mn-C14Mn were prepared. The experimental binary phase diagram of C10Mn-C14Mn was established by differential thermal analysis (DTA), IR and X-ray diffraction. In the phase diagram new material (n-C10H21NH3)(n-C14H29NH3)MnCl4 and two eutectoid invariants were observed, two eutectic points temperatures are about 29.8 and 27.9°C. Contrasting other
similar system, there are three noticeable solid solution ranges (α, β, γ) at the left and right boundary and middle of the
Authors:S. Lin, J. Tseng, M. Lee, T. Wu, and C. Shu
Styrene is an important chemical in the petrochemical industry. In recent years, there have been sporadic releases, runaway
reactions, fires, and thermal explosion accidents incurred by styrene and its derivatives worldwide. The purpose of this study
was to estimate the impact of styrene and its derivatives of α-methylstyrene (AMS) and trans-β-methylstyrene (TBMS) contacting with benzaldehyde. Experiments were carried out to evaluate the thermokinetic parameters
estimated by differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III). TAM III was used to determine
the fundamental thermokinetics under various isothermal temperatures, 80, 90 and 100°C. This autocatalytic reaction was demonstrated
in thermal curves. After styrene was contacted with benzaldehyde, the exothermic onset temperature (T0) and the total heat of reaction (Qtotal) were altered by DSC tests. When benzaldehyde is mixed with AMS and TBMS, the reaction time will be shorter but the enthalpy
reduced, as revealed by TAM III tests.
As AMS and TBMS, respectively, were contacted with benzaldehyde, both exothermic phenomena were changed during the reaction
excursion. According to the results of this research, an operator should dictate the oxygen concentration in order to avoid
any potential hazards during handling and transportation.
Authors:W. Yan, C. Ma, J. Wu, W. Zhang, and D. Jang
Crystal of the complex Ni2L (ClO4)2 was obtained by reaction of Ni(ClO4)2 and macrocyclic ligand H2L, where L2– is the dinucleating macrocycle with two 2,6-di(aminomethyl)-4-methyl phenolate entities combined by the same two lateral chains, –(CH2)2–NH–(CH2)2–, at the amino nitrogens. The thermal decomposition processes of the title complex were studied in a dynamic atmosphere of dry argon using TG-DTG. The kinetic analysis of the first and second thermal decomposition steps were performed via the TG-DTG curves, and the kinetic parameters were obtained from analysis of the TG-DTG curves with integral and differential methods. The most probable kinetic function was suggested by comparison of the kinetic parameters.
Authors:J. Chen, S. Wu, S. Lin, H. Hou, and C. Shu
The exothermic decomposition of cumene hydroperoxide (CHP) in cumene liquid was characterized by isothermal microcalorimetry,
involving the thermal activity monitor (TAM). Unlike the exothermic behaviors previously determined from an adiabatic calorimeter,
such as the vent sizing package 2 (VSP2), or differential scanning calorimetry (DSC), thermal curves revealed that CHP undergoes
an autocatalytic decomposition detectable between 75 and 90°C. Previous studies have shown that the CHP in a temperature range
higher than 100°C conformed to an nth order reaction rate model. CHP heat of decomposition and autocatalytic kinetics behavior were measured and compared with
previous reports, and the methodology and the advantages of using the TAM to obtain an autocatalytic model by curve fitting
are reported. With various autocatalytic models, such as the Prout-Tompkins equation and the Avrami-Erofeev rate law, the
best curve fit among models was also investigated and proposed.
Authors:Y. Chang, J. Lee, S. Wu, C. Chen, and C. Shu
Flammable chemicals are frequently encountered in industrial processes. Under the safe operation basis and for fire/explosion
danger prevention, it is imperative to recognize the flammability characteristics of these processes, especially under the
working scenarios for elevated pressure and temperature.
This study was conducted to investigate fire and explosion properties, including the explosion limits (LEL and UEL), maximum
explosion overpressure (Pmax), maximum rate of explosion pressure rise (dP/dt)max, gas or vapor deflagration index (Kg) and explosion class (St) of various acetone/water solutions (100, 75, 50 and 25 vol.%) at higher initial pressure/temperature up to 2 atm and 200°C
via a 20-L-Apparatus. We further discussed the safety-related parameters and fire/explosion damage degree variations in the
above aqueous acetone within 1 atm and 150°C. The results offered a successful solution for evaluating the flammability hazard
effect in such a relevant crucial process with elevated pressure and temperature.
The Federal Radiological Monitoring and Assessment Center (FRMAC) is authorized by the Federal Radiological Emergency Response Plan to coordinate all off-site radiological response assistance to state and local governments, in the event of a major radiological emergency in the United States. The FRMAC is established by the U.S. Department of Energy, National Nuclear Security Administration, to coordinate all Federal assets involved in conducting a comprehensive program of radiological environmental monitoring, sampling, radioanalysis, quality assurance, and dose assessment. During an emergency response, the initial analytical data is provided by portable field instrumentation. As incident responders scale up their response based on the seriousness of the incident, local analytical assets and mobile laboratories add additional capability and capacity. During the intermediate phase of the response, data quality objectives and measurement quality objectives are more rigorous. These higher objectives will require the use of larger laboratories, with greater capacity and enhanced capabilities. These labs may be geographically distant from the incident, which will increase sample management challenges. This paper addresses emergency radioanalytical capability and capacity and its utilization during FRMAC operations.
Authors:J. Wang, B. Bao, M. Wu, X. Sun, X. Zhang, J. Hu, and G. Ye
This paper reports on the qualitative and quantitative analyses of light hydrocarbons produced by radiation degradation of
N,N-diethylhydroxylamine. The results show that when the absorbed doses are between 10 and 1000 kGy, the main light hydrocarbons
are methane, ethane, ethene, propane and n-butane. Their volume fractions are increased with the increase of the dose. The
volume fraction of ethene is also increased at low doses with the increase of the dose, but it is decreased with the increase
of dose at high doses.
Authors:X. Geng, Y. Wu, J. Song, X. Geng, J. Xing, and Z. Lei
The displacement adsorption enthalpies (ΔH) of the refolding of lysozyme (Lys) denatured by
1.8 mol L–1 guanidine hydrochloride (GuHCl)
on a moderately hydrophobic surface at 298 K, pH 7.0 and various (NH4)2SO4
concentrations were determined by using a Micro DSC-III calorimeter. The study
shows that the effect of salt concentrations on the three fractions of the
enthalpy is that with increasing (NH4)2SO4
concentrations, the molecular conformation enthalpy of the adsorbed Lys has
probably no distinct change at 1.8 mol L–1
GuHCl; the adsorption affinity enthalpy (exothermic) becomes more negative;
and the dehydration enthalpy (endothermic) decreases. At lower salt concentrations,
the dehydration, especially squeezing water molecules led by molecular conformation,
which leads to an entropy-driving process, predominates over the adsorption
affinity (also including the orderly orientation of molecular conformation),
while at higher salt concentrations, the latter is prior to the former for
contribution to ΔH and induces an
enthalpy-driving process. Also, the optimal NH4)2SO4
concentration favoring refolding and renaturing of Lys denatured by 1.8 mol
L–1 GuHCl was found.
Authors:T. Wu, W. Dai, G. Xiao, F. Shu, J. Yao, and J. Li
With the low permeability and high swelling property, Gaomiaozi (GMZ) bentonite is regarded as the favorable candidate backfilling
material for a potential repository. The diffusion behaviors of HTO in GMZ bentonite were studied to obtain effective diffusion
coefficient (De) and accessible porosity (ε) by through- and out-diffusion experiments. A computer code named Fitting for diffusion coefficient
(FDP) was used for the experimental data processing and theoretical modeling. The De and ε values were (5.2–11.2) × 10−11 m2/s and 0.35–0.50 at dry density from 1,800 to 2,000 kg/m3, respectively. The De values at 1,800 kg/m3 was a little higher than that of at 2,000 kg/m3, whereas the De value at 1,600 kg/m3 was significantly higher (approximately twice) than that of at 1,800 and 2,000 kg/m3. It may be explained that the diffusion of HTO mainly occurred in the interlayer space for the highly compacted clay (dry
density exceeding 1,300 kg/m3). 1,800 and 2,000 kg/m3 probably had similar interlayer space, whereas 1,600 kg/m3 had more. Both De and ε values decreased with increasing dry density. For compacted bentonite, the relationship of De and ε could be described by Archie’s law with exponent n = 4.5 ± 1.0.
Authors:X. X. Yu, J. W. Wu, Z. K. Liang, M. Q. Zhao, and X. J. Xu
A high-speed counter-current chromatography (HSCCC) method was established for the isolation and purification of isochlorogenic acid A from Lonicera japonica Thunb. The two-phase solvent system was composed of n-hexane:ethyl acetate: isopropanol:water (2:3:2:5, v/v/v/v). From 150 mg of the ethyl acetate fraction of L. japonica Thunb, 19.65 mg of isochlorogenic acid A was obtained in a one-step HSCCC separation, with a purity of 99.1%, as determined by high-performance liquid chromatography (HPLC). The structure was further identified by ultraviolet (UV), mass spectrometry (MS) and nuclear magnetic resonance (NMR).