Chatter Detection in Hot Strip Mill Process based on Modified Independent Component Analysis

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Improved Relay Feedback Method Under Noisy and Disturbance Environments

This paper presents a new relay feedback method to guarantee the accuracy of the enhanced relay feedback method. The new method uses the integrals of a process input and output to tune Proportional-Integral-Derivative (PID) controllers automatically even if the process input and output are contaminated by measurement noises and disturbances. This feedback method uses a new disturbance estimator and a new noise magnitude estimator to remove the effects of noises and disturbances on estimates of frequency response data. Simulation and application to a real system to control liquid level demonstrate that the proposed methods provide fairly accurate ultimate data of the process and that the PID controller tuned by the proposed method achieves control faster and with less overshoot than the conventional auto-tuning strategy based on the conventional relay feedback method.11Nsciescopu

Chatter Detection and Diagnosis in Hot Strip Mill Process With a Frequency-Based Chatter Index and Modified Independent Component Analysis

In this article, we propose a framework to monitor the chatter phenomenon and to diagnose the cause variables of chatter occurred in the hot strip mill process (HSMP). For monitoring chatter, we develop a chatter index (CI) that quantifies chatter to confirm its occurrence. Based on the data classified as normal by the CI, a multivariate statistical process monitoring model for detecting chatter is constructed using the modified independent component analysis (MICA) method. The monitoring results show that the model based on the MICA outperforms other models based on the principal component analysis and independent component analysis. For the diagnosis of the cause variables of detected chatter, various contribution plots can be used. In this article, we develop a relative contribution plot for a more obvious diagnosis than the existing contribution plot. Using this, we diagnose and analyze the cause variables of the detected chatter in the HSMP.11Nsciescopu

Triptycene-based quinone molecules showing multi-electron redox reactions for large capacity and high energy organic cathode materials in Li-ion batteries

Organic redox-active molecules have attracted great attention for next generation electrode materials due to their promising advantages of low cost, natural abundance, environmental friendliness, and structural diversity. Here we propose a new molecular design strategy to achieve both large specific capacity and high energy organic cathode materials for Li-ion batteries using a triptycene scaffold as a minimal linker between the redox-active units. The triptycene molecule bearing three benzoquinone (BQ) units in a rigid tripod structure exhibits five-electron redox reactions that practically provide a specific capacity as high as 387 mA h g−1 in Li-ion coin cells. By combining electrochemical analyses with theoretical DFT calculations, we figure out that the 3-D arrangements of BQ units in triptycene not only facilitate a highly reversible access to a large number of redox states but also raise the redox potential. Due to the large capacity and the increased redox potential, the triptycene electrode can deliver a specific energy up to 1032 W h kg−1 at 0.1C-rate, which is close to two times the specific energy of the conventional inorganic cathode materials. It is also demonstrated that the cycling performance of triptycenes can be greatly improved by fabricating nanocomposite materials with the ordered mesoporous carbon CMK3.11Nsciescopu

Observation of Suppressed Interdiffusion in FeRh/FePt-Ta Bilayer Thin Films

FeRh/FePt bilayers onMgO (100) substrates were fabricated by rf-magnetron sputtering, and the magnetic properties and microstructures of the bilayers were studied in terms of Ta addition to the storage layer. Compared to undoped FeRh/FePt bilayers, FeRh/FePt-Ta bilayer films showed improved magnetic properties and lower degree of interdiffusion. The FeRh/FePt-Ta bilayers clearly demonstrated the AFM-FM transition. Reduced interdiffusion by Ta segregation along grain boundaries was speculated to be a possible cause for the observed improvement in magnetic properties when fabricated at high temperature.X111sciescopu

Strategic Approach for Enhancing Sensitivity of Ammonia Gas Detection: Molecular Design Rule and Morphology Optimization for Stable Radical Anion Formation of Rylene Diimide Semiconductors

Herein, a strategic approach to enhance the sensitivity of ammonia gas detection using organic semiconductors by boosting the efficiency of ammonia gas-induced stable radical anion formation (SRAF) is reported. This is achieved through rational molecular design and engineering of field-effect transistors (FETs). New rylene diimide derivatives are designed and used to prepare molecular templates for efficient SRAF in thin films, and they are applied as gas-adsorbing active layers in FETs. Substituting linear-shaped perfluoroalkyl (PF) groups to pi-electron-deficient naphthalene diimide (NDI) backbone enhances the ammonia gas detection limit to 200 ppb, attributed to the strong electron-withdrawing capability and low steric hindrance of PF groups. Replacing the core backbone (NDI) with perylene diimide (PDI) while retaining the PF group further enhances gas-responsivity up to 18.17 (1700% increase in current) due to the enlarged pi-conjugated bridge area. Computational characterization further supports that high electron affinity of the PDI-PF molecules and a larger gas-adsorption area in the PDI core result in the exceptional ammonia gas sensitivity. In addition, beneficial molecular orientation and nanopore formation of PDI-PF facilitate gas adsorption, resulting in remarkably enhanced gas-responsivity. The results indicate that molecular engineering for high-efficiency SRAF suggests a new strategy for developing high-sensitivity ammonia sensing platforms

Squid-inspired and wirelessly controllable display for active camouflage in aquatic-environment

Abstract Achieving optimal camouflage in an aquatic environment necessitates the ability to modulate transmittance in response to the surrounding obscurity and potential threats. This adaptation involves a dynamic transition from transparency to a deep-blue color, especially in low-light or dark situations. Such a strategy promotes a seamless assimilation with the surroundings, enabling the absorption of searchlights and, subsequently, diminishing the risk of detection by predators. Therefore, the presence of sophisticated mechanisms that facilitates stable and efficient control of transmittance is imperative, enabling smooth transition between transparent and deep-blue hues within the aquatic environment. This study presents nature-inspired programmable camouflage system that integrates an electrochromic display as the primary transmittance change element and a wireless base module for power and data transmission. Such technology offers a robust and flexible construction, ensuring stable operation as demonstrated through mechanical-fatigue experiments and quantitative simulation. A custom circuit and a power-control software package enable active control of multiple electrochromic displays while submerged in water