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61.
The present discourse is directed toward the community that wishes to generate or use flow reactor data from complex chemical reactions as kinetic model development and validation targets. Various methods for comparing experimental data and computational predictions are in evidence in the literature, along with limited insights into uncertainties associated with each approach. Plug flow is most often assumed in such works as a simple, chemically insightful physical reactor model; however, only brief qualitative justifications for such an interpretation are typically offered. Modern tools permit the researcher to quantitatively confirm the validity of this assumption. In a single complex reaction system, chemical time scales can change dramatically with extent of reaction of the original reactants and with transitions across boundaries separating low temperature, intermediate temperature, and chain branched (high temperature) kinetic regimes. Such transitions can violate the underlying assumptions for plug flow interpretation. Further, uncertainties in reaction initialization may confound interpretation of experiments for which the plug flow assumption may be appropriate. Finally, various methods of acquiring experimental data can also significantly influence experimental interpretations. The following discussions provide important background for those interested in critically approaching the relatively vast literature on the application of flow reactors for generating kinetic validation data. The less frequently discussed influences of reactor simulation assumptions on modeling predictions are addressed through examples for which the kinetic behavior of specific reactant combinations may cause experimental observations to depart locally from plug flow behavior. 相似文献
62.
Ablimit Abdukadir Kamalbek Omar Lutpulla Hushur 《Fullerenes, Nanotubes and Carbon Nanostructures》2016,24(10):662-666
The aromaticity of the fullerene C38 isomers and their molecular ions is examined by the topological resonance energy (TRE) method. The aromaticity order obtained by the TRE method is compared with relative energies found in DFT calculation results reported in literature. It is found that all C38 isomers exhibit antiaromaticity when in the neutral state. However, they are highly aromatic in the hexaanionic states. The minimum bond resonance energy (min BRE) method is utilized to estimate the kinetically stability of the C38 isomers and their molecular ions. According to the min BRE method, C38 isomers are only have kinetic stability in penta- and hexavalent molecular anionic states. 相似文献
63.
A typical 1.5 MW wind turbine suitable for Xuzhou City is designed and simulated in this paper. The wind turbine blade-hub-tower coupling system and most of the parameters are designed and calculated in the design process. In the kinetic analysis process, the force analysis under 4 different situations are taken to verify the structure design, which are under quiescent condition, under random angle and random wind turbine, under maximal wind speed and over maximal wind speed. At last, the modal analysis selected the turbine hub and tower to solve the inherent frequencies and vibration modes. The first 5 order inherent frequencies and vibration modes of the hub and tower are solved to verify the design rationality. 相似文献
64.
《Journal of Process Control》2014,24(6):957-965
The knowledge of kinetic reaction rates is important for monitoring and controlling biotechnological processes. However, the lack of on-line sensors for this purpose and the inherent problems with numerical differentiation make observers indispensable. In this work, we propose the use of a weighted variable gain super-twisting observer (WVGSTO), applicable to a class of second-order nonlinear systems that include a measurable weight on the unmeasured variable and the possibility of bounding the perturbations with measurable functions. This estimation method is illustrated with an academic example and then applied to a fed-batch bioprocess. 相似文献
65.
The present research was devoted to studying the kinetics of the artificial rancidification of peanut oil (PO) when a sample of this oil was isothermally heated at 180 °C in an air stream. The formation of radical species due to heating was evaluated using a radical index whose value was determined using a biosensor method based on a superoxide dismutase (SOD), while the increasing toxicity was monitored using a suitable toxicity measuring probe based on the Clark electrode and immobilized yeast cells. 相似文献
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68.
Ahmad Hosseini-Bandegharaei Mohammad Karimzadeh Masoud Sarwghadi Aliasghar Heydarbeigi Seyyed Hossein Hosseini Mehdi Nedaie Hassan Shoghi 《Chemical Engineering Research and Design》2014
Adsorption of Pb(II) ion by a novel extractant-impregnated resin, EIR, was studied as a function of various experimental parameters using batch adsorption experiments. The new EIR was prepared by impregnating gallocyanine (GCN) onto Amberlite XAD-16 resin beads. The EIR was characterized by nitrogen analysis and SEM micrographs. The new EIR showed excellent selectivity factor values (α) for Pb(II) adsorption respect to other metal ions. The effects of some chemical and physical variables were evaluated and the optimum conditions were found for Pb(II) removal from aqueous solutions. The equilibrium adsorption isotherm was fitted with the Langmuir adsorption model. The maximum adsorption capacity (qmax) of EIR for Pb(II) ions was found to be 367.92 mg g−1. The kinetic studies showed that the intra-particle diffusion is the rate-controlling step. Also, the intra-particle diffusion coefficients, Dip values, were of the order of 10−12 m2 s−1. The values of enthalpy (ΔH°) were positive, which confirms the endothermic nature of adsorption process. Also, the positive entropy changes (ΔS°) were showed that the randomness increased along with the adsorption process. In addition, the obtained negative values of Gibbs free energy (ΔG°) indicated feasible and spontaneous nature of the adsorption process at different temperatures. The new adsorbent was very stable so that it can be successfully used for many consecutive cycles without significant loss in its adsorption capacity. 相似文献
69.
双酚A型环氧树脂阳离子紫外光固化动力学的研究 总被引:1,自引:0,他引:1
以双酚A型环氧树脂为主体成分构成紫外阳离子光固化体系,用常规的最低光固化速度测试方法和实时傅立叶变换红外光谱法研究了各种条件对体系光固化速度的影响。结果表明,光引发剂的种类和浓度可以有效地改变光固化速度,环氧稀释剂会大幅度降低光固化速度,而羟基化合物的加入只是轻微降低光固化速度。在三元体系中,其光固化速度并不是几种作用的简单叠加,而是更加类似于羟基化合物的性质。使得通过调节合适的组分构成和配合,能够获得具有合适光固化速度的紫外阳离子光固化配方,从而会大大扩展其应用的技术领域。 相似文献
70.
利用FTIR、XRD研究了抚顺油页岩(OS)的组成结构,TG-MS分析了过渡金属盐催化剂(页岩灰作为载体负载NiCl2·6H2O、CuCl2·2H2O、ZnCl2)对OS热解的催化作用和挥发分析出的影响规律,采用Coats-Redfern模型分析过渡金属盐催化剂对OS热解活化能的影响.结果表明,OS中矿物质主要由石英、... 相似文献