Article
Materials Science, Multidisciplinary
Jerome A. Cuenca, Soumen Mandal, Evan L. H. Thomas, Oliver A. Williams
Summary: This study presents a microwave plasma model to investigate the spatial heteroepitaxial growth of polycrystalline diamond on Si in a chemical vapor deposition reactor. The model demonstrates radial variation in growth rate over small samples with different sample holders. Experimental validations using Raman spectroscopy and scanning electron microscopy are conducted. The results reveal the importance of sample holder design for achieving uniform diamond films.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Fakhrony Sholahudin Rohman, Mohd Roslee Othman, Dinie Muhammad, Ashraf Azmi, Iylia Idris, Rushdan Ahmad Ilyas, Samah Elsayed Elkhatif, Muhammad Nazri Murat
Summary: The study introduced neural Wiener model predictive control (NWMPC) and a soft sensor model to address fouling formation in reactor vessels, enabling online monitoring and controlling of the F-D processes for faster LDPE grade transition and lower resource consumption compared to state space model control utilizing only linear blocks.
Article
Chemistry, Multidisciplinary
Fakhrony Sholahudin Rohman, Mohd Roslee Othman, Dinie Muhammad, Ashraf Azmi, Iylia Idris, Rushdan Ahmad Ilyas, Samah Elsayed Elkhatif, Muhammad Nazri Murat
Summary: The study introduces the neural Wiener model predictive control (NWMPC) to address fouling formation in low-density polyethylene (LDPE) polymerization, and utilizes a soft sensor model to monitor and control the fouling-defouling process. Compared to state space model predictive control (SSMPC), NWMPC proves to be faster in controlling the transition of LDPE grade and consumes fewer resources.
Article
Engineering, Electrical & Electronic
Carolina Albea, Antonino Sferlazza, Francisco Gordillo, Fabio Gomez-Estern
Summary: This paper applies hybrid dynamical systems theory to the analysis and control of switched converters with PWM inputs, capturing modulation effects by enlarging the state vector. A control law based on Lyapunov function is proposed, and steady state jitter is analyzed to limit output chattering. The approach provides a deeper understanding of modulation effects in closed-loop dynamics, avoiding issues associated with averaged models, with experimental validation of the method.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2021)
Article
Engineering, Chemical
Yessin Ammar, Patrick Cognet, Michel Cabassud
Summary: A novel modelling methodology using artificial neural networks is proposed to develop a global model for predicting the time evolution of concentrations of all species in the reaction medium. Different recurrent neural networks are utilized to estimate specific species as a function of operating parameters and concentrations, which are then assembled into a complex global model. This approach successfully represents the kinetic evolution of chemical species under varied operating conditions, and the neural network-based global model is integrated into a hybrid model for transposing reactions to a semi-batch chemical reactor.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Engineering, Mechanical
Yulai Zhao, Yun-Peng Zhu, Qingkai Han, Yang Liu
Summary: This paper proposes a method for rotor condition monitoring based on nonlinear features, which can accurately extract weak nonlinear features. This method uses a novel tailored data-driven NARX modeling approach to extract the partial dynamic properties of concern and reconstructs the low-order harmonics of concern using the harmonic product spectrum and least mean squares method. Nonlinear Output Frequency Response Functions are then calculated from the tailored NARX model as features for rotor condition monitoring. Experimental results show that the obtained features based on the proposed tailored NARX modeling approach are more robust and accurate than conventional methods when assessing rotor faults. The proposed approach provides a reference for inspecting the assembly quality of components such as bearings and the online health monitoring of rotating machinery.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Chemistry, Physical
Zeeshan Khan, Haroon Ur Rasheed, Ilyas Khan, Hanaa Abu-Zinadah, Maha A. Aldahlan
Summary: This study investigates the influence of chemical interaction and dynamic micropolar convective heat transfer flow on Casson fluid caused by a moving wedge immersed in a porous material. The heating effect of magnetized porous matrix heating is also considered. The mathematical formulation is expressed in the form of partial differential equations, and the dimensionless set of ordinary equations is obtained via a transformation framework and solved using the RK4 built-in function in MATLAB. The results show the effects of material parameters on various properties such as flow field, temperature, concentration, drag force, and Nusselt number.
Article
Engineering, Chemical
Li-Kun Yuan, Bao-Chang Xu, Zhi-Shan Liang, Ya-Xin Wang
Summary: Proper models and parameter identification are required for operation designs on rapid developed advanced chemical processes, and these models need input-output data sets with high information content. The optimal parameter identification experiment, which requires additional persistently exciting input, can ensure the process dynamic information. However, this experiment is time-consuming and high-cost, and may interfere with the process operation. In low-cost identification, limited external excitations or extracted informative segments from historical data can support chemical process modeling.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2023)
Article
Physics, Applied
Ahmed Sallam, Shima Shahab
Summary: This study focuses on the use of holographic acoustic lenses (HALs) to generate complex focused ultrasound fields. Nonlinear effects and waveform distortion are analyzed, and it is observed that nonlinear effects significantly affect the reconstruction of the pressure pattern. The study also highlights the importance of nonlinear effects in accurately predicting cavitation zones.
APPLIED PHYSICS LETTERS
(2022)
Article
Agriculture, Dairy & Animal Science
Abbas Shibak, Ali Maghsoudi, Mohammad Rokouei, Homayoun Farhangfar, Hadi Faraji-Arough
Summary: This study aimed to find the most suitable and recommendable mathematical function for describing the ostrich egg production pattern. The Wood and McNally functions were found to be the best-fitted functions, while the Yang function was the least appropriate.
Article
Engineering, Aerospace
Sebastian Alphonse, Geoffrey A. Williamson
Summary: Estimating the signal transmitted by a noncooperating radar is crucial for radar countermeasures. This study proposes improving noise resilience by constraining estimation to a low-dimensional signal space, focusing on nonlinear frequency modulated radar signals. The quality of low-dimensional signal estimates is found to be more accurate at low SNRs with a smaller number of sensors compared to unconstrained high-dimensional estimation methods.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2021)
Article
Computer Science, Information Systems
Mariia Sokil, Andriy Andrukhiv, Solomiia Fedushko, Yuriy Syerov, Gregus M. L. Michal
Summary: The study focuses on the influence of impulse moments on nonlinear torsional oscillations of a homogeneous constant cross-section body, developing mathematical models and identifying resonant and non-resonant processes. The findings confirm the characteristics of resonant oscillations and the significant impact of pulse momentum on the amplitude during primary resonance.
Article
Automation & Control Systems
Chaoxu Mu, Ke Wang, Changyin Sun
Summary: This article investigates the optimal control problem for nonlinear nonzero-sum differential game in the environment of no initial admissible policies while considering the control constraint. An adaptive learning algorithm is developed based on policy iteration technique to approximate obtain the Nash equilibrium. The algorithm, implemented as a critic-actor architecture, is proven to be convergent and ensures stability during the learning phase with the use of stable operators.
IEEE TRANSACTIONS ON SYSTEMS MAN CYBERNETICS-SYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
Li Li, Yoshiharu Omura, Xu-Zhi Zhou, Qiu-Gang Zong, Robert Rankin, Chao Yue, Sui-Yan Fu
Summary: This study presents observations of periodic chorus wave emissions in the troughs of compressional ultralow frequency (ULF) waves using Van Allen Probes. The spectral gap of chorus waves was found to widen as the spacecraft moved towards higher latitudes, and the intensity and frequency range of chorus waves increased after a substorm injection. The periodic occurrence of chorus waves was attributed to the modulation of threshold amplitude for nonlinear growth of chorus waves by the second spatial derivative of ULF compressional magnetic field. The findings also supported the applicability of the nonlinear theory in describing the chorus wave generation and damping, together with their modulations by ULF waves.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Engineering, Aerospace
Ning Li, Dongyang Cheng, Pingping Lu, Gaofeng Shu, Zhengwei Guo
Summary: In this article, a new jamming method against synthetic aperture radar (SAR) based on the nonlinear frequency-modulated (NLFM) signal is proposed. Compared with the traditional linear frequency-modulated (LFM) signal, the NLFM signal has a time-frequency structure that mismatched with the linear matched filter of SAR, resulting in a stronger and more flexible jamming effect.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2023)
Article
Chemistry, Multidisciplinary
Robert Currie, Daliborka Nikolic, Menka Petkovska, David S. A. Simakov
ISRAEL JOURNAL OF CHEMISTRY
(2018)
Review
Chemistry, Multidisciplinary
Menka Petkovska, Daliborka Nikolic, Andreas Seidel-Morgenstern
ISRAEL JOURNAL OF CHEMISTRY
(2018)
Article
Engineering, Chemical
Milos Mandic, Vladimir Dikic, Menka Petkovska, Branislav Todic, Dragomir B. Bukur, Nikola M. Nikacevic
CHEMICAL ENGINEERING SCIENCE
(2018)
Article
Chemistry, Applied
Nikola Nikacevic, Branislav Todic, Milos Mandic, Menka Petkovska, Dragomir B. Bukur
Article
Engineering, Multidisciplinary
Danica V. Brzic, Menka T. Petkovska
MATHEMATICAL PROBLEMS IN ENGINEERING
(2019)
Article
Electrochemistry
Saikrishnan Kandaswamy, Antonio Sorrentino, Shivangi Borate, Luka A. Zivkovic, Menka Petkovska, Tanja Vidakovic-Koch
ELECTROCHIMICA ACTA
(2019)
Article
Engineering, Chemical
Daliborka Nikolic, Andreas Seidel-Morgenstern, Menka Petkovska
CHEMICAL ENGINEERING SCIENCE
(2020)
Article
Engineering, Environmental
Matthias Felischak, Lothar Kaps, Christof Hamel, Daliborka Nikolic, Menka Petkovska, Andreas Seidel-Morgenstern
Summary: Forced periodic operation has the potential for process improvements, with NFR analysis being able to efficiently predict its effects. This paper experimentally demonstrated forced periodic operation in the hydrolysis of acetic anhydride, confirming the predictions of NFR analysis.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Chemical
Carsten Seidel, Daliborka Nikolic, Matthias Felischak, Menka Petkovska, Andreas Seidel-Morgenstern, Achim Kienle
Summary: This study investigated the potential of alternative forced periodic operation modes in methanol production through numerical optimization, and found that significant improvements in both objective functions can be achieved by utilizing periodic inputs.
Article
Engineering, Chemical
Daliborka Nikolic, Carsten Seidel, Matthias Felischak, Tamara Milicic, Achim Kienle, Andreas Seidel-Morgenstern, Menka Petkovska
Summary: This study presents the potential to improve performance of a methanol synthesis reactor through forced periodical operations using the Nonlinear Frequency Response method. The analysis was extended to simultaneous modulations of two inputs, determining optimal forcing parameters for maximizing methanol production. While improvement is possible for all combinations, it is not significant in some cases, with the highest improvement predicted for the simultaneous modulation of the inlet partial pressure of CO and the inlet volumetric flow rate.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Chemical
Daliborka Nikolic, Carsten Seidel, Matthias Felischak, Tamara Milicic, Achim Kienle, Andreas Seidel-Morgenstern, Menka Petkovska
Summary: This two-part paper presents a comprehensive study on improving performance criteria of a methanol synthesis reactor through forced periodical operations. The study uses the Nonlinear Frequency Response method to analyze single input modulations and will be extended to simultaneous modulations of two inputs for significant performance enhancements.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Chemical
Luka A. Zivkovic, Tanja Vidakovic-Koch, Menka Petkovska
Article
Engineering, Chemical
Luka A. Zivkovic, Viktor Milic, Tanja Vidakovic-Koch, Menka Petkovska
Article
Engineering, Chemical
Qing Han, Mengqing Shi, Linkai Han, Di Liu, Mingwei Tong, Yuxin Xie, Zhonghua Xiang
Summary: Developing highly efficient bifunctional oxygen electrocatalysts is crucial for zinc-air flow batteries. Metal-organic frameworks (MOFs) and covalent organic polymers (COPs) have emerged as promising alternatives due to their designable and controllable atomic-level structures. However, their catalytic performances are limited by conductivity and catalytic activity. In this study, nanosheet FeNi-MOF and iron phthalocyanine rich COP hybrid materials are assembled through the pi-pi stacking effect to create highly efficient bifunctional electrocatalysts. The resulting catalyst exhibits superior catalytic performance and stability, making it a promising candidate for zinc-air flow batteries.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Daria Grigorash, Dmytro Mihrin, Rene Wugt Larsen, Erling H. Stenby, Wei Yan
Summary: The article introduces a new approach to describe the cross-association between molecules, allowing for the simulation of weakly bound molecular complexes with different conformations in mixtures. By incorporating this approach into the equation of state, accurate predictions of vapor-liquid equilibrium and liquid-liquid equilibrium can be made. The new method is validated through experiments on alcohol and acid mixtures, with the results compared to experimental data, demonstrating its accuracy and reliability.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Mohammed Al-Sharabi, Daniel Markl, Vincenzino Vivacqua, Prince Bawuah, Natalie Maclean, Andrew P. E. York, Axel Zeitler
Summary: This study used terahertz pulsed imaging to investigate the transport process of different solvents into ceramic catalytic materials. The results showed that the heating rate of the samples influenced the water transport rate, while the viscosity of 1-octanol slowed down its transport.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Chukwunonso Anyaoku, Sati Bhattacharya, Rajarathinam Parthasarathy
Summary: This study aimed to enhance understanding of settling dynamics in viscoelastic fluids by developing a semi-empirical correlation and a dimensionless ratio, which accurately described the characteristics of settling suspensions.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Antti I. Koponen, Janika Viitala, Atsushi Tanaka, Baranivignesh Prakash, Olli-Ville Laukkanen, Ari Jasberg
Summary: This study focuses on the development of foam application chemicals for the paper and board industry. The research explores the rheology of the polyvinyl alcohol foam used in the process. Measurements were conducted to determine the foam viscosity and slip flow. The results suggest that slip flow contributes significantly to the total flow rate, and the obtained viscosity and slip models provide a solid foundation for industrial processes.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Dalei Sun, Jinghui Cai, Yating Yang, Zhiwu Liang
Summary: In this study, Fe-doped alpha-Bi2O3 catalysts with different Fe/Bi molar ratios were synthesized and utilized in the carbonylation of isobutyl amine with CO2. The results showed that Fe doping significantly enhanced the catalytic abilities of alpha-Bi2O3.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Yuan Tian, Xinxin Wang, Yanrong Liu, Wenping Hu
Summary: This paper predicts the solubility of nitrogen gas in ionic liquids (ILs) using two quantitative structure-property relationship (QSPR) models. By combining machine learning methods and ionic fragments contribution method, the accuracy and reliability of the prediction models are improved.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Liwang Wang, Wei Liu, Pan Yang, Yulong Chang, Xiaoxu Duan, Lingyu Xiao, Yaoming Hu, Jiwei Wu, Liang Ma, Hualin Wang
Summary: This study investigates the effective phase interfacial area (ae) of hydro-jet cyclones at different injection angles. The results show that a 45 degrees upward incidence angle yields the most favorable flow field characteristics for efficient mass transfer. The significant enhancement in ae of the hydro-jet cyclones offers the advantage of reducing equipment volume and cost savings.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Chuanjun Wu, Jiangzhi Chen, Jiyue Sun, I-Ming Chou, Shenghua Mei, Juezhi Lin, Lei Jiang
Summary: In this study, the solubility of H2S hydrate in water was measured using Raman spectroscopy. The results showed that the solubility increases with temperature under certain equilibrium conditions, and the solubility also depends on pressure and temperature under different equilibrium conditions. A thermodynamic model based on the van der Waals-Platteeuw theory was developed to predict the solubility, demonstrating its accuracy.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Lorenzo Brivio, Serena Meini, Mattia Sponchioni, Davide Moscatelli
Summary: This study investigates the influence of three main parameters and proposes a kinetic model to predict the optimal operating conditions for high yield of dimethyl terephthalate (DMT) in the chemical recycling process of polyethylene terephthalate (PET).
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Hongju Lin, Fanhui Liao, Yanchang Chu, Mingyu Xie, Lun Pan, Yuanyuan Wang, Lijian Leng, Donghai Xu, Le Yang, Gangfeng Ouyang
Summary: A honeycomb NiCo/C-Na catalyst with a micro-meso-macroporous structure has been fabricated and shown to have significantly higher catalytic activity for the decarboxylation of fatty acids. It also proves to be efficient in upgrading sludge HTL bio-crude, resulting in a biofuel with decreased viscosity and increased density.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Xiaoxian Li, Rui Li, Min Lin, Mingde Yang, Yulong Wu
Summary: A series of coated non-noble metal porous carbon catalysts were synthesized and applied to the aqueous-phase deoxygenation of algal bio-oil. One of the catalysts showed excellent deoxygenation selectivity and catalytic activity at 250 degrees C. The catalyst exhibited good hydrothermal stability and the reaction mechanism was proposed based on product analysis and active site analysis.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
M. V. Chudakova, M. V. Popov, P. A. Korovchenko, E. O. Pentsak, A. R. Latypova, P. B. Kurmashov, A. A. Pimenov, E. A. Tsilimbaeva, I. S. Levin, A. G. Bannov, A. V. Kleymenov
Summary: A series of catalysts with different potassium contents were prepared using solution combustion synthesis and characterized using various techniques. The results showed that the potassium content affected the phase composition and texture of the catalysts. The addition of a small amount of potassium resulted in a change in particle size distribution, leading to higher hydrogen yield. The Ni-1%K2O/Al2O3 catalyst exhibited the highest hydrogen yield at temperatures of 675 and 750 degrees Celsius.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Aliakbar Roosta, Nima Rezaei
Summary: In this study, we modified the electrolyte cubic plus association equation of state (e-CPA EoS) and integrated it with two electrical conductivity models to estimate the electrical conductivity of 11 monovalent electrolyte solutions in water. The modified e-CPA model demonstrated better performance and the hybridization with electrical conductivity models resulted in two predictive models for estimating the electrical conduction of dilute and concentrated electrolyte solutions. These predictive models showed relative average percentage deviations (AARD) of 11.15% and 13.87% over wide ranges of temperature and electrolyte concentration.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Engineering, Chemical
Haoren Niu, Jianzheng Wang, Qingzhu Jia, Qiang Wang, Jin Zhao, Fangyou Yan
Summary: A study developed two quantitative structure-property relationship models for the complexation performance of alpha- and beta-cyclodextrins and validated their stability and predictive ability through internal and external validation. The models showed robustness and satisfactory performance, as demonstrated by the experimental results and model validations. These models can effectively predict the binding constants between cyclodextrins and various types of molecules, providing valuable tools for cyclodextrin design.
CHEMICAL ENGINEERING SCIENCE
(2024)