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- Author or Editor: Chang Liu x
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Abstract
The combustion behaviors and kinetic parameters of three parent coals (A1, A2, and A3) and their blends (A1/A2 and A2/A3) have been evaluated under oxidizing atmosphere (O2 and N2 mixtures), using a non-isothermal thermo-gravimetric analyzer. The aim of this study is to investigate the interaction between the blended components during the process of co-combustion, and the effects of blending ratio and oxygen concentration (10, 15, and 21%) on combustion performance of blended coals. When high reactivity and low reactivity coals are co-combusted, double peaks are observed in the DTG curves, and significant interaction occurs in the temperature range between the two peaks (T p1 and T p2). The activation energies obtained by Coats–Redfern method indicate that the activation energies of blended coals are lower than that of parent coals. The combustibility index S is used to evaluate the combustion performance of blended coals, and the results show the non-additive effects of the combustion characteristics of blended coals. The increased oxygen concentration results in a significant improvement of combustion performance of blended coals. In addition, as the blending ratio of high reactivity coal is increased, the oxygen can greatly enhance the combustion stability of blended coals.
Abstract
Environmental samples of beach sand taken at northern Taiwan have been monitored using a coincident gamma-ray spectrometer. The concentration of134Cs, under intense interference from natural and other artificial radioactivity, is determined as low as 0.2 Bq/kg dry. The accumulation of trace levels of134Cs originates from the discharge of nuclear power plants nearby.
Abstract
Hydrogen titanate nanotubes were prepared by K2Ti2O5 with water vapour treatment. TG/DTG techniques were used to investigate their water content and dehydration kinetics. It was shown that chemical formula for hydrogen titanate nanotubes is TiO2·0.58H2O which is close to H2Ti2O5. The activation energy of dehydration from hydrogen titanate nanotubes is about 60 kJ/mol according the calculation of Friedman and Flynn–Wall–Ozawa methods. With multivariate non-linear regression calculation, it was found that dehydration of hydrogen titanate nanotubes is a two-step consecutive reaction. The first step is a reaction of nth order with autocatalysis. The second step is a reaction of nth order.
Abstract
Many concerns over unsafe or unknown properties of multi-walled carbon nanotubes (MWNTs) have been raised. The thermal characteristics regarding stability would represent potential hazards during the production or utilization stage and could be determined by calorimetric tests for various thermokinetic parameters. Differential scanning calorimetry (DSC) was employed to evaluate the thermokinetic parameters for MWNTs at various compositions. Thermoanalytical curves showed that the average heat of decomposition (ΔH d) of the MWNTs samples in a manufacturing process was about 31,723 J g−1, by identifying them as an inherently hazardous material. In this study, significant thermal analysis appeared in the presence of sulfuric acid (H2SO4). From the DSC experiments, the purification process of MWNTs could induce an unexpected reaction in the condition of batch addition with reactants of H2SO4. The results can be applied for designing emergency relief system and emergency rescue strategies during a perturbed situation or accident.
Abstract
This paper employs bibliometric methods to observe collaboration patterns of scientific publications in biotechnology, information and computer technology, future energy, and nanotechnology among different institutions in Taiwan. The results show primary domestic and international collaborative patterns, the effect of collaborative papers on the world-wide average, collaborative networks, and the distribution of institutions on global map. The findings suggest that domestic collaboration in each area is higher in proportion than international collaboration. Biotechnology leads in both domestic and international collaborative percentage. Among cooperative benchmarking countries, the US and China are the main partners. Collaboration among research institutes and universities is the most frequent collaborative pattern in each area except biotechnology, which tends to occur between hospitals and universities. On average, international collaborative papers tend to have greater effect, except in nanotechnology. Academia Sinica collaborated frequently with foreign institutes in each research field. A further analysis on how each collaborative group forms is recommended, especially collaboration among the Triple-Helix relationships.
Abstract
In the first part, LiCl-KCl-UCl3 and LiCl-KCl-UCl3-UCl4 molten salts were prepared, which were studied employing cyclic voltammetry and chronopotentiometry techniques, respectively. It was determined that the reduction of U(IV) to uranium metal takes two steps. Firstly, U(IV) is reduced to U(III). Then, the reduction of U(III) to uranium metal occurs in a step with a global exchange of three electrons. Cyclic voltammetry studies indicated that at low sweep rates, the reduction of U(III) to uranium is reversible. However, a mixed control of both diffusion and electrontransfer is observed as the sweep rate increases. The diffusion coefficient of U(III) and the formal potential of U(III)/U versus Ag/AgCl reference electrode in these two salt systems were calculated respectively. In second part, based on the data of the electrode processes of uranium ions, electrodeposition of uranium metal was carried out. Uranium deposits were prepared adopting a 304 stainless steel electrode in the molten LiCl-KCl-UCl3 and LiCl-KCl-UCl3-UCl4, respectively by employing suitable electrolytic techniques. The morphology of the deposits and the cross-section of the cathode were investigated by SEM. It was determined that at the beginning of the deposition process, uranium product alloys with stainless steel and forms a thin layer, and then uranium begins to grow adhering to the layer.
Abstract
Background
Researchers are only just beginning to understand the neurocognitive drivers of addiction-like eating behaviours, a highly distressing and relatively common condition. Two constructs have been consistently linked to addiction-like eating: distress-driven impulsivity and cognitive inflexibility. Despite a large body of addiction research showing that impulsivity-related traits can interact with other risk markers to result in an especially heightened risk for addictive behaviours, no study to date has examined how distress-driven impulsivity interacts with cognitive inflexibility in relation to addiction-like eating behaviours. The current study examines the interactive contribution of distress-driven impulsivity and cognitive inflexibility to addiction-like eating behaviours.
Method
One hundred and thirty-one participants [mean age 21 years (SD = 2.3), 61.8% female] completed the modified Yale Food Addiction Scale, the S-UPPS-P impulsivity scale, and a cognitive flexibility task. A bootstrap method was used to examine the associations between distress-driven impulsivity, cognitive inflexibility, and their interaction with addiction-like eating behaviours.
Results
There was a significant interaction effect between distress-driven impulsivity and cognitive flexibility (P = 0.03). The follow-up test revealed that higher distress-driven impulsivity was associated with more addiction-like eating behaviours among participants classified as cognitively inflexible only.
Conclusion
The current findings shed light on the mechanisms underlying addiction-like eating behaviours, including how traits and cognition might interact to drive them. The findings also suggest that interventions that directly address distress-driven impulsivity and cognitive inflexibility might be effective in reducing risk for addiction-like eating and related disorders.
Abstract
Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.
Abstract
The decomposition of organic peroxides by their relatively weak oxygen linkage and hydroperoxide radical in the presence of reaction solution is one of the thermal hazards for triggering a runaway reaction. Runaway incidents may occur in oxidation reactors, vacuum condensation reactors, tank lorries, or storage tanks. In NFPA 432 organic peroxides in NFPA 432 are classified as flammable. The exothermic behaviors of solid organic peroxides, dicumene peroxide, benzoyl peroxide, and lauroyl peroxide, were determined by differential scanning calorimetry (DSC), and vent sizing package 2 (VSP2). Relevant data detected by DSC provided thermal stability information, such as exothermic onset temperature (T 0), maximum heat-releasing peak (T max), and heat of decomposition (ΔH d). VSP2 was used to perform the bench scale situation for pushing the expected or unexpected reaction to undergo runaway reaction. Onset temperature, maximum pressure, self-heating rate ((dT dt −1)max), and pressure-release rate ((dP dt −1)max) were therefore obtained and explained. These results are essentially crucial in process design for an inherently safer approach.
Abstract
Ca-47 radioactive tracer was used to determine the phamocodynamics, distribution pattern, absorption and bioavailability of a new type calcium supplement in rabbit prepared by plasma technology. Our results indicate that calcium from the new nutrient is mainly deposited in bone 6 or 7 days after oral administration. The absorption rate of this new calcium preparation is estimated to be 30–40 %.
