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Kinetic roughening transition and missing regime transition of melt crystallized polybutene-1 tetragonal

Motoi YAMASHITA

《化学科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 125-134 doi: 10.1007/s11705-009-0001-3

摘要: The morphology and lateral growth rate of polybutene-1 ( -PB1) have been investigated for crystallization from the melt over a wide range of crystallization temperatures from 50 to 110°C. The morphology of -PB1 crystals is a rounded shape at crystallization temperatures lower than 85°C, while lamellar single crystals possess faceted morphology at higher crystallization temperatures. The kinetic roughening transition occurs around 85°C. The nucleation and growth mechanism for crystallization does not work below 85°C, since the growth face is rough. However, the growth rate shows the supercooling dependence derived from the nucleation and growth mechanism. The nucleation theory seems still to work even for rough surface growth. Possible mechanisms for the crystal growth of this polymer are discussed.

关键词: isotactic polybutene-1     tetragonal phase (form Ⅱ)     melt crystallization     growth rate     kinetic roughening     morphology    

Performance of ionic polymer-metal composite (IPMC) with different surface roughening methods

Ning JIN, Bangfeng WANG, Kan BIAN, Qi CHEN, Ke XIONG,

《机械工程前沿(英文)》 2009年 第4卷 第4期   页码 430-435 doi: 10.1007/s11465-009-0053-6

摘要: Based on permeation and double chemical reduction technology, this paper researches the manufacture of Pt-ionic polymer metal composites (IPMC) and the effect of three types of surface roughening methods on the manufacture and performance of IPMC. The roughening methods include manual polishing, sanding machine polishing, and plasma surface treatment. The appearance and scanning electron microscopy (SEM) features, electro-active deformation and surface resistance characteristics of these IPMC specimens were obtained and compared through specimen tests. The results of the tests indicate that surface roughening technology obviously influences the performance of IPMC. The uniformity and compactness of the metal deposited on the surface and inside the Nafion film are improved by improving surface roughening uniformity. However, the electro-active deformation capability and surface resistance of the specimens decrease at the same time. There is an approximate linear increase relationship between the driving voltage and the bending deformation of the IPMC specimen within a certain voltage range. Under the same specimen dimension, constraints, and driving voltage (3V), the maximum electro-active bending deformation angles of the specimens are about 60°, 45°, and 15° for manual polishing, sanding machine roughening, and plasma treatment, respectively.

关键词: ionic polymer metal composites (IPMC)     surface roughening     scanning electron microscopy (SEM) analyze     actuator     electroless plating    

Electrocoagulation process for the treatment of metal-plating wastewater: Kinetic modeling and energy

Fatih Ilhan, Kubra Ulucan-Altuntas, Yasar Avsar, Ugur Kurt, Arslan Saral

《环境科学与工程前沿(英文)》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1152-1

摘要: The wastewater from industrial area was treated by EC via Fe and Al electrodes. Cu, Ni, Cr and Zn were highly removed at the first minutes, simultaneously. Pseudo-2nd-order was found to be more suitable for kinetics. Adsorption capacities based on kinetic modeling were observed as Cr>Cu>Ni>Zn. The chemical cost in the case of pH adjustment after EC was less as 3.83 $/m3. It is known that wastewater produced by the metal-plating industry contains several heavy metals, which are acidic in nature and therefore toxic for the environment and for living creatures. In particular, heavy metals enter the food chain and accumulate in vital organs and cause serious illness. The precipitation of these metals is mostly achieved by pH adjustment, but as an alternative to this method, the electrocoagulation process has investigated in this study using iron and aluminum electrodes. The effects of the pH adjustment on removal before and after the electrocoagulation process were investigated, and cost analyses were also compared. It was observed that a high proportion of removal was obtained during the first minutes of the electrocoagulation process; thus, the current density did not have a great effect. In addition, the pH adjustment after the electrocoagulation process using iron electrodes, which are 10% more effective than aluminum electrodes, was found to be much more efficient than before the electrocoagulation process. In the process where kinetic modeling was applied, it was observed that the heavy metal removal mechanism was not solely due to the collapse of heavy metals at high pH values, and with this modeling, it was seen that this mechanism involved adsorption by iron and aluminum hydroxides formed during the electrocoagulation process. When comparing the ability of heavy metals to be adsorbed, the sequence was observed to be Cr>Cu>Ni>Zn, respectively.

关键词: Electrochemical treatment     Heavy metals     Kinetic modeling     Pseudo first order kinetic     Pseudo second order kinetic    

Thermogravimetric kinetic analysis of

SUKARNI,SUDJITO,Nurkholis HAMIDI,Uun YANUHAR,I.N.G. WARDANA

《能源前沿(英文)》 2015年 第9卷 第2期   页码 125-133 doi: 10.1007/s11708-015-0346-x

摘要: The thermal behavior of combustion in air atmosphere were investigated by performing experiments on STA PT1600 Thermal Analyzer at heating rates of 10°C/min, 40°C/min and 70°C/min and range of temperatures from room temperature to 1200°C. The kinetic parameters were evaluated by using Kissinger and Ozawa methods. The result showed that combustion occurred in five stages. Started with initial devolatilization, the main thermal decomposition and combustion process, transition stage, the combustion of char and the last stage was the slow burning reaction of residual char. In line with increasing heating rate, the mass loss rate increased as well, but it delayed the thermal decomposition processes toward higher temperatures. The average activation energy at the main thermal decomposition stage and the stage of char combustion were approximately 251 kJ/mol and 178 kJ/mol, respectively.

关键词: Nannochloropsis oculata     combustion     kinetic parameters     air atmosphere     thermogravimetric    

Experimental and kinetic study on laminar flame speeds of ammonia/syngas/air at a high temperature and

《能源前沿(英文)》 2022年 第16卷 第2期   页码 263-276 doi: 10.1007/s11708-021-0791-7

摘要: The laminar flame speeds of ammonia mixed with syngas at a high pressure, temperature, and different syngas ratios were measured. The data obtained were fitted at different pressures, temperatures, syngas ratios, and equivalence ratios. Four kinetic models (the Glarborg model, Shrestha model, Mei model, and Han model) were compared and validated with experimental data. Pathway, sensitivity and radical pool analysis are conducted to find out the deep kinetic insight on ammonia oxidation and NO formation. The pathway analysis shows that H abstraction reactions and NHi combination reactions play important roles in ammonia oxidation. NO formation is closely related to H, OH, the O radical produced, and formation reactions. NO is mainly formed from reaction, HNO+ H= NO+ H2. Furthermore, both ammonia oxidation and NO formation are sensitive to small radical reactions and ammonia related reactions.

关键词: ammonia mixed with syngas     laminar flame speed     kinetic model     sensitivity analysis     pathway analysis    

Kinetic study of hydrodesulfurization of coker gas oil in a slurry reactor

Haiding XIANG, Tiefeng WANG

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 139-144 doi: 10.1007/s11705-013-1323-8

摘要: Coker gas oil (CGO) is a poor-quality feedstock for fluidized bed catalytic cracking (FCC) or hydrocracking. The pretreatment of CGO, especially hydrotreating, can significantly improve the product quality and protect the catalyst. In this work, we studied the hydrodesulfurization (HDS) of CGO in a slurry reactor. All the experiments were carried out in an autoclave using a NiMo/Al O catalyst at reaction temperature 340°C–400°C, pressure 6–10 MPa, and stirring speed 800 r·min , with hydrogen-to-oil ratio in the range of 500–1500. The effects of the operating parameters on the desulfurization ratio were investigated and discussed. A macro reaction kinetic model was established for the HDS of CGO in the slurry reactor.

关键词: coker gas oil     hydrodesulfurization     slurry reactor     reaction kinetic model    

photoreduction process in a laboratory-scale photoreactor by computational fluid dynamic and reaction kinetic

《化学科学与工程前沿(英文)》 2022年 第16卷 第7期   页码 1149-1163 doi: 10.1007/s11705-021-2096-0

摘要: The production of solar fuels via the photoreduction of carbon dioxide to methane by titanium oxide is a promising process to control greenhouse gas emissions and provide alternative renewable fuels. Although several reaction mechanisms have been proposed, the detailed steps are still ambiguous, and the limiting factors are not well defined. To improve our understanding of the mechanisms of carbon dioxide photoreduction, a multiphysics model was developed using COMSOL. The novelty of this work is the computational fluid dynamic model combined with the novel carbon dioxide photoreduction intrinsic reaction kinetic model, which was built based on three-steps, namely gas adsorption, surface reactions and desorption, while the ultraviolet light intensity distribution was simulated by the Gaussian distribution model and Beer-Lambert model. The carbon dioxide photoreduction process conducted in a laboratory-scale reactor under different carbon dioxide and water moisture partial pressures was then modeled based on the intrinsic kinetic model. It was found that the simulation results for methane, carbon monoxide and hydrogen yield match the experiments in the concentration range of 10−4 mol·m–3 at the low carbon dioxide and water moisture partial pressure. Finally, the factors of adsorption site concentration, adsorption equilibrium constant, ultraviolet light intensity and temperature were evaluated.

关键词: carbon dioxide photoreduction     computational fluid dynamic simulation     kinetic model     Langmuir adsorption    

for damage detection in functionally graded carbon nanotube-reinforced composite plates using modal kinetic

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1453-1479 doi: 10.1007/s11709-021-0767-z

摘要: This paper proposes a new Deep Feed-forward Neural Network (DFNN) approach for damage detection in functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates. In the proposed approach, the DFNN model is developed based on a data set containing 20 000 samples of damage scenarios, obtained via finite element (FE) simulation, of the FG-CNTRC plates. The elemental modal kinetic energy (MKE) values, calculated from natural frequencies and translational nodal displacements of the structures, are utilized as input of the DFNN model while the damage locations and corresponding severities are considered as output. The state-of-the art Exponential Linear Units (ELU) activation function and the Adamax algorithm are employed to train the DFNN model. Additionally, in order to enhance the performance of the DFNN model, the mini-batch and early-stopping techniques are applied to the training process. A trial-and-error procedure is implemented to determine suitable parameters of the network such as the number of hidden layers and the number of neurons in each layer. The accuracy and capability of the proposed DFNN model are illustrated through two distinct configurations of the CNT-fibers constituting the FG-CNTRC plates including uniform distribution (UD) and functionally graded-V distribution (FG-VD). Furthermore, the performance and stability of the DFNN model with the consideration of noise effects on the input data are also investigated. Obtained results indicate that the proposed DFNN model is able to give sufficiently accurate damage detection outcomes for the FG-CNTRC plates for both cases of noise-free and noise-influenced data.

关键词: damage detection     deep feed-forward neural networks     functionally graded carbon nanotube-reinforced composite plates     modal kinetic energy    

Kinetic study of the methanol to olefin process on a SAPO-34 catalyst

Mehdi SEDIGHI,Kamyar KEYVANLOO

《化学科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 306-311 doi: 10.1007/s11705-014-1440-z

摘要: In this paper, a new kinetic model for methanol to olefin process over SAPO-34 catalyst was developed using elementary step level. The kinetic model fits well to the experimental data obtained in a fixed bed reactor. Using this kinetic model, the effect of the most important operating conditions such as temperature, pressure and methanol space-time on the product distribution has been examined. It is shown that the temperature ranges between 400 °C and 450 °C is appropriate for propene production while the medium temperature (450 °C) is favorable for total olefin yield which is equal to 33%. Increasing the reactor pressure decreases the ethylene yield, while medium pressure is favorable for the propylene yield. The result shows that the ethylene and propylene and consequently the yield of total olefins increase to approximately 35% with decreasing the molar ratio of inlet water to methanol.

关键词: methanol to olefin     SAPO-34     kinetic modeling     elementary step    

Application of micro-genetic algorithm for calibration of kinetic parameters in HCCI engine combustion

HUANG Haozhong, SU Wanhua

《能源前沿(英文)》 2008年 第2卷 第1期   页码 86-92 doi: 10.1007/s11708-008-0003-8

摘要: The micro-genetic algorithm (?GA) as a highly effective optimization method, is applied to calibrate to a newly developed reduced chemical kinetic model (40 species and 62 reactions) for the homogeneous charge compression ignition (HCCI) combustion of -heptane to improve its autoignition predictions for different engine operating conditions. The seven kinetic parameters of the calibrated model are determined using a combination of the Micro-Genetic Algorithm and the SENKIN program of CHEMKIN chemical kinetics software package. Simulation results show that the autoignition predictions of the calibrated model agree better with those of the detailed chemical kinetic model (544 species and 2 446 reactions) than the original model over the range of equivalence ratios from 0.1–1.3 and temperature from 300–3 000 K. The results of this study have demonstrated that the mGA is an effective tool to facilitate the calibration of a large number of kinetic parameters in a reduced kinetic model.

关键词: homogeneous     different     combustion     autoignition     compression    

Prediction of high-density polyethylene pyrolysis using kinetic parameters based on thermogravimetric

《环境科学与工程前沿(英文)》 2023年 第17卷 第1期 doi: 10.1007/s11783-023-1606-3

摘要:

● Reducting the sampling frequency can enhance the modelling process.

关键词: HDPE     Pyrolysis     Kinetics     Thermogravimetric     ANOVA     Artificial neural network    

Simultaneous removal of NO and chlorobenzene on VO/TiO granular catalyst: Kinetic study and performance

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1363-5

摘要:

• A V2O5/TiO2 granular catalyst for simultaneous removal of NO and chlorobenzene.

关键词: NOx     Chlorobenzene     Simultaneous removal     Kinetic study     Performance prediction     V2O5/TiO2     Graphical abstract    

Oxidation-extraction desulfurization of model oil over Zr-ZSM-5/SBA-15 and kinetic study

Chuanzhu LU,Hui FU,Huipeng LI,Hua ZHAO,Tianfeng CAI

《化学科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 203-211 doi: 10.1007/s11705-014-1420-3

摘要: ZSM-5/SBA-15 composite molecular sieves were synthesized using post-synthesis method and characterized by X-ray diffraction and N adsorption-desorption. The oxidative-extration desulfurization of model oil was investigated by using hydrogen peroxide as the oxidant, tetrabutyl ammonium bromide as phase transfer catalyst, dimethyl sulfoxide as extractant, and Zr-ZSM-5/SBA-15, Ag-ZSM-5/SBA-15, Ce-ZSM-5/SBA-15 as catalyst. Under the optimal conditions, the desulfurization rate decreases in the order: Zr-ZSM-5/SBA-15>Ce-ZSM-5/SBA-15>Ag-ZSM-5/SBA-15. The highest desulfurization rate is 84.53% under the catalysis of Zr-ZSM-5/SBA-15. Kinetics analysis shows that the reaction is pseudo-first-order with the activation energy of 44.23 kJ/mol.

关键词: composite molecular sieve     oxidation desulfuration     extraction     kinetic    

Kinetic energy based model assessment and sensitivity analysis of vortex induced vibration of segmental

Nazim Abdul NARIMAN

《结构与土木工程前沿(英文)》 2017年 第11卷 第4期   页码 480-501 doi: 10.1007/s11709-017-0435-5

摘要: In this paper, semi 3D models for segmental Bridge decks are created in ABAQUS CFD program with the support of MATLAB codes to simulate and analyze vortex shedding generated due to wind excitation through considering the stationary position of the deck. Three parameters (wind speed, deck streamlined length and dynamic viscosity of the air) are dedicated to study their effects on the kinetic energy of the system in addition to the shapes and patterns of the vortices. Two benchmarks from the literature Von Karman and Dyrbye and Hansen are considered to validate the vortex shedding aspects for the CFD models. Good agreement between the results of the benchmarks and the semi 3D models has been detected. Latin hypercube experimental method is dedicated to generate the surrogate models for the kinetic energy of the system and the lift forces. Variance based sensitivity analysis is utilized to calculate the main sensitivity indices and the interaction orders for all the three parameters. The kinetic energy approach performed very well in revealing the rational effects and the roles of each parameter in the generation of vortex shedding and predicting vortex induced vibration of the deck.

关键词: vortex induced vibration     reynolds number     kinetic energy     vorticity     latin hypercube sampling    

Kinetic Monte Carlo simulations of plasma-surface reactions on heterogeneous surfaces

Daniil Marinov

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 815-822 doi: 10.1007/s11705-019-1837-9

摘要: Reactions of atoms and molecules on chamber walls in contact with low temperature plasmas are important in various technological applications. Plasma-surface interactions are complex and relatively poorly understood. Experiments performed over the last decade by several groups prove that interactions of reactive species with relevant plasma-facing materials are characterized by distributions of adsorption energy and reactivity. In this paper, we develop a kinetic Monte Carlo (KMC) model that can effectively handle chemical kinetics on such heterogenous surfaces. Using this model, we analyse published adsorption-desorption kinetics of chlorine molecules and recombination of oxygen atoms on rotating substrates as a test case for the KMC model.

关键词: plasma-surface interaction     kinetic Monte Carlo     plasma nano technology    

标题 作者 时间 类型 操作

Kinetic roughening transition and missing regime transition of melt crystallized polybutene-1 tetragonal

Motoi YAMASHITA

期刊论文

Performance of ionic polymer-metal composite (IPMC) with different surface roughening methods

Ning JIN, Bangfeng WANG, Kan BIAN, Qi CHEN, Ke XIONG,

期刊论文

Electrocoagulation process for the treatment of metal-plating wastewater: Kinetic modeling and energy

Fatih Ilhan, Kubra Ulucan-Altuntas, Yasar Avsar, Ugur Kurt, Arslan Saral

期刊论文

Thermogravimetric kinetic analysis of

SUKARNI,SUDJITO,Nurkholis HAMIDI,Uun YANUHAR,I.N.G. WARDANA

期刊论文

Experimental and kinetic study on laminar flame speeds of ammonia/syngas/air at a high temperature and

期刊论文

Kinetic study of hydrodesulfurization of coker gas oil in a slurry reactor

Haiding XIANG, Tiefeng WANG

期刊论文

photoreduction process in a laboratory-scale photoreactor by computational fluid dynamic and reaction kinetic

期刊论文

for damage detection in functionally graded carbon nanotube-reinforced composite plates using modal kinetic

期刊论文

Kinetic study of the methanol to olefin process on a SAPO-34 catalyst

Mehdi SEDIGHI,Kamyar KEYVANLOO

期刊论文

Application of micro-genetic algorithm for calibration of kinetic parameters in HCCI engine combustion

HUANG Haozhong, SU Wanhua

期刊论文

Prediction of high-density polyethylene pyrolysis using kinetic parameters based on thermogravimetric

期刊论文

Simultaneous removal of NO and chlorobenzene on VO/TiO granular catalyst: Kinetic study and performance

期刊论文

Oxidation-extraction desulfurization of model oil over Zr-ZSM-5/SBA-15 and kinetic study

Chuanzhu LU,Hui FU,Huipeng LI,Hua ZHAO,Tianfeng CAI

期刊论文

Kinetic energy based model assessment and sensitivity analysis of vortex induced vibration of segmental

Nazim Abdul NARIMAN

期刊论文

Kinetic Monte Carlo simulations of plasma-surface reactions on heterogeneous surfaces

Daniil Marinov

期刊论文