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SSRN 2024年

作者： Lambert, Jerry Ceruti, Amedeo Spliethoff, Hartmut Technical University of Munich TUM School of Engineering and Design Chair of Energy Systems Boltzmannstr. 15 Garching85747 Germany Department of Energy and Process Engineering Germany

Optimal routing and investment decisions are key design criteria to reduce the high investment costs of district heating systems. However, these optimization problems have prohibitively high computational costs for large districts. Four different linear optimization frameworks are benchmarked in this study in order to compare their computational scaling. The frameworks exhibit significant differences in solving times for synthetic benchmarks and real-world urban districts of up to 9587 potential edges. The new open-source framework topotherm, developed for this work, exhibits the best computational performance when only one time step is optimized. The comparison between the models Résimont, DHmin, DHNx, and topotherm show two main trends. First, fewer integer variables do not necessarily translate to lower solving times, and second, using redundant binary variables, which introduce symmetries into the constraints, leads to higher solving times. None of the considered optimization frameworks is able to solve the largest benchmark problems for five time steps within the allowed time limit and tolerance. These findings highlight the challenges of and pressing need to develop efficient models for simultaneous optimization of district heating network topology, pipe sizing, and operation. © 2024, The Authors. All rights reserved.

关键词： District heating

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A Facile Li_(2)TiO_(3) Surface Modification to Improve the Structure Stability and Electrochemical Performance of Full Concentration Gradient Li-Rich Oxides

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Energy & Environmental Materials 2024年第3期7卷 41-48页

作者： Naifang Hu Yuan Yang Lin Li Yuhan Zhang Zhiwei Hu Lan Zhang Jun Ma Guanglei Cui Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101China Institute of Materials Science and Engineering Ocean University of ChinaQingdao 266100China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China Max Planck Institute for Chemical Physics of Solids Nothnitzer Strasse 40Dresden D-01187Germany CAS Key Laboratory of Green Process and Engineering Beijing Key Laboratory of Ionic Liquids Clean ProcessState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Shandong Energy Institute Qingdao 266101China

Full concentration gradient lithium-rich layered oxides are catching lots of interest as the next generation cathode for lithium-ion batteries due to their high discharge voltage,reduced voltage decay and enhanced rate performance,whereas the high lithium residues on its surface impairs the structure stability and long-term cycle ***,a facile multifunctional surface modification method is implemented to eliminate surface lithium residues of full concentration gradient lithium-rich layered oxides by a wet chemistry reaction with tetrabutyl titanate and the post-annealing *** realizes not only a stable Li_(2)TiO_(3)coating layer with 3D diffusion channels for fast Li^(+)ions transfer,but also dopes partial Ti^(4+)ions into the sub-surface region of full concentration gradient lithium-rich layered oxides to further strengthen its crystal ***,the modified full concentration gradient lithium-rich layered oxides exhibit improved structure stability,elevated thermal stability with decomposition temperature from 289.57℃to 321.72℃,and enhanced cycle performance(205.1 mAh g^(-1)after 150 cycles)with slowed voltage drop(1.67 mV per cycle).This work proposes a facile and integrated modification method to enhance the comprehensive performance of full concentration gradient lithium-rich layered oxides,which can facilitate its practical application for developing higher energy density lithium-ion batteries.

关键词： full concentration gradient lithium-rich layered oxides structure stability surface modification

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Deep Learning Assisted High Throughput Screening of Ionic Liquid Electrolytes for Nrr and Co2rr

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SSRN 2023年

作者： Guo, Yandong Song, Yingying Chen, Junwu Yuan, Menglei Dong, Kun Bohai University Liaoning Jinzhou121013 China Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China

Non-aqueous ionic liquids (ILs) with high solubility of both nitrogen and carbon dioxide have greater potential to be used as electrolytes for NRR and CO2RR due to reduced HER effects and high conductivity as well as low viscosity. However, conventional experimental methods for screening IL electrolytes are time-consuming and labor-intensive. In order to solve such difficulties, deep learning assisted screen of ILs was investigated in this work. The experimental data including six IL properties like viscosity, conductivity, melting point, density, nitrogen solubility, and carbon dioxide solubility of were collected approximately 40,000. The graph neural network model exhibited excellent ability in predicting performance in comparison to the traditional machine learning models. Furthermore, the transfer learning approach was employed to enhance the model prediction on a small dataset. A virtual database was constructed with 2 million IL structures to be used for high throughput screening. Using the properties of the IL [P6,6,6,14][eFAP] with higher Faradaic conversion efficiency as the input thresholds, we performed high throughput screening of the virtual dataset, obtained 141 ILs based on the Synthetic Complexity Score (SCScore), in which tetracyanoborate based ([B(CN)4]-) ILs and perchlorate based ([ClO4]-) ILs accounted for large percentages, and finally identified 8 ILs superior to [P6,6,6,14][eFAP] as ideal electrolyte materials for both NRR and CO2RR that have been reported to be synthesizable. Our works provides the effective tool for designing the novel IL-based electrolytes and will be helpful for the researchers who are seeking the ILs with benign ability in NRR and CO2RR. © 2023, The Authors. All rights reserved.

关键词： Ionic liquids

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Effect of Magnesium Hydroxide on the Thermal Stability, Latent Heat and Flammability Properties of composite material based on Phase Change Materials

Effect of Magnesium Hydroxide on the Thermal Stability, Late...

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2024 International Conference on Technologies and Materials for Renewable Energy, Environment and Sustainability, Tmrees24Gr 2024

作者： Othmen, Marwa Tlili, Nawel Alkan, Cemil Hannachi, Ahmed Research Laboratory of Process Engineering and Industrial Systems National School of Engineers of Gabes University of Gabes Omar Ibn El-Khattab St. Gabes6029 Tunisia National School of Engineers of Gafsa University of Gafsa Gafsa Tunisia Faculty of Arts and Sciences at Gaziosmanpaşa Tokat Gaziosmanpaşa University Tokat Turkey

Polyurethane-Phase Change Materials (PU-PCM) composites are used for thermal regulation aiming to conserve and efficiently manage thermal energy. These materials combine the properties of PU, such as low thermal conductivity, low density and excellent mechanical properties as a thermal insulator, with the benefits of PCM allowing thermal energy storage, which greatly reduce energy consumption in heating and cooling. Adding a flame retardant to the PU-PCM composition improves fire resistance. The objective of this study is the preparation and characterization of a composite material based on PU rigid foam containing 30% by mass of commercial paraffin waxes as PCM, together with magnesium hydroxide as flame retardant. A series of samples were prepared by incorporating different percentages of Mg(OH)2, ranging from 1 % to 5 %, with and without the PCM. Various thermal and chemical characterization tests were carried out. The results indicate that the structure of the PU cells is not affected by the increase of the Mg(OH)2 incorporation rate. In terms of thermal properties, the addition of 1% flame retardant increases the latent heat from 25.9 J/g to 39.68 J/g. As the amount of Mg(OH)2 incorporated increases, the flame retardancy increases. © Published under licence by IOP Publishing Ltd.

关键词： Flame resistance

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Cyclic random graph models predicting giant molecules in hydrocarbon pyrolysis

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Physical Review E 2025年第3期111卷 034303-034303页

作者： Perrin E. Ruth Vincent Dufour-Décieux Christopher Moakler Maria K. Cameron Department of Mathematics University of Maryland College Park Maryland 20742 USA Energy & Process Systems Engineering ETH Zürich 8092 Zürich Switzerland Applied Physics Laboratory Johns Hopkins Baltimore Maryland 21218 USA

Hydrocarbon pyrolysis is a complex chemical reaction system at extreme temperature and pressure conditions involving large numbers of chemical reactions and chemical species. Only two kinds of atoms are involved: carbons and hydrogens. Its effective description and predictions for new settings are challenging due to the complexity of the system and the high computational cost of generating data by molecular dynamics simulations. However, the ensemble of molecules present at any moment and the carbon skeletons of these molecules can be viewed as random graphs. Therefore, an adequate random graph model can predict molecular composition at a low computational cost. We propose a random graph model featuring disjoint loops and assortativity correction and a method for learning input distributions from molecular dynamics data. The model uses works of Karrer and Newman [Phys. Rev. E 82, 066118 (2010)] and Newman [Phys. Rev. Lett. 89, 208701 (2002)] as building blocks. We demonstrate that the proposed model accurately predicts the size distribution for small molecules as well as the size distribution of the largest molecule in reaction systems at the pressure of 40.5 GPa, temperature range of 3200–5000 K, and H/C ratio range from 2.25 as in octane through 4 as in methane.

关键词： Molecular dynamics

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Experimental on Ultrasonic Testing of Ultra-High-Toughness Cementitious Composite Under Mechanical Loading Damage 2nd

Experimental on Ultrasonic Testing of Ultra-High-Toughness C...

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2nd International Conference on Advanced Civil engineering and Smart Structures, ACESS 2023

作者： Peng, Sheng Sun, Huang-Kai Yang, Zhao He, Li Wu, Cai School of Urban Construction Wuhan University of Science and Technology Wuhan430065 China Hubei Provincial Engineering Research Center of Urban Regeneration Wuhan430065 China School of Civil Engineering Wuhan University Wuhan430062 China Hubei Province Key Laboratory of Systems Science in Metallurgical Process Wuhan430065 China School of Civil Engineering Hubei Engineering University Wuhan432000 China

ISBN: (纸本)9789819715138

In order to study the damage degree and ultrasonic pulse velocity (UPV) of ultra-high-toughness cementitious composite (UHTCC), this paper conducted mechanical load damage tests on three types of fiber-reinforced UHTCC. The study showed a clear correlation, with the UPV of the specimens decreasing significantly as the damage degree increases. A model for determining the damage stage of materials using UPV was proposed. It is noteworthy that this sensitivity varies among different fiber types, with Polyethylene Fiber (PEF) and Steel Fiber (SF) samples exhibiting more significant UPV reductions compared to Polyvinyl Alcohol Fiber (PVAF) samples. These findings provided a reference for the study of damage assessment methods for UHTCC structures based on UPV tests. This approach can serve as an early warning system to prevent catastrophic failures of UHTCC structures, enhancing their safety and durability in civil engineering applications. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Steel fibers

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Nearest Neighbor Search-Based Modification of RRI Data with Premature Atrial Contraction and Premature Ventricular Contraction

Nearest Neighbor Search-Based Modification of RRI Data with ...

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SICE International Symposium on control systems (ISCS)

作者： Sifeng Chen Shota Kato Koichi Fujiwara Manabu Kano Department of Systems Science Kyoto University Kyoto Japan Department of Materials Process Engineering Nagoya University Nagoya Japan

Heart rate variability (HRV) analysis plays an essential role in healthcare. HRV features cannot be extracted accurately from the R-R interval (RRI) when RRI data contains artifacts. Previous research for modifying RRI data with artifacts considered premature atrial contraction (PAC) and premature ventricular contraction (PVC), which are the most common types of extrasystoles occurring every day in healthy persons. This research proposed three new RRI modification algorithms for PAC and PVC using nearest neighbor search (NNS) algorithms: k-nearest neighbors (KNN), clustering-KNN (CKNN), and approximate nearest neighbors (ANN). The present work demonstrated that the ANNbased RRI modification (ANN-RM) algorithm achieved lower root mean squared errors (RMSEs) than the CKNN-based RRI modification algorithm and the highest computational speed. The RMSEs of ANN-RM for PAC and PVC were 23.0 ms and 26.2 ms, respectively.

关键词： Rail to rail inputs Clustering algorithms Medical services Nearest neighbor methods Approximation algorithms Feature extraction control systems

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Laser-Induced Cavitation for controlling Crystallization from Solution

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Physical Review Letters 2023年第12期131卷 124001-124001页

作者： Nagaraj Nagalingam Aswin Raghunathan Vikram Korede Christian Poelma Carlas S. Smith Remco Hartkamp Johan T. Padding Hüseyin Burak Eral Process and Energy Department Delft University of Technology Leeghwaterstraat 39 2628 CB Delft Netherlands Delft Center for Systems and Control Delft University of Technology Mekelweg 2 2628 CD Delft Netherlands

We demonstrate that a cavitation bubble initiated by a Nd:YAG laser pulse below breakdown threshold induces crystallization from supersaturated aqueous solutions with supersaturation and laser-energy-dependent nucleation kinetics. Combining high-speed video microscopy and simulations, we argue that a competition between the dissipation of absorbed laser energy as latent and sensible heat dictates the solvent evaporation rate and creates a momentary supersaturation peak at the vapor-liquid interface. The number and morphology of crystals correlate to the characteristics of the simulated supersaturation peak.

关键词： Cavitation Crystallization Drop or bubble formation Heat transfer Liquid-solid phase transition Nucleation Ionic fluids Microfluidics Finite-element method Laser techniques Optical microscopy

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Analysis of Equilibrium Point and Genetic Algorithm Design of Observer-Based PID controller for Membrane Bioreactor

Analysis of Equilibrium Point and Genetic Algorithm Design o...

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2021 International Automatic control Conference, CACS 2021

作者： Changsila, Yanita Banjerdpongchai, David Intelligent Control Automation of Process Systems Research Unit Dept. of Electrical Engineering Faculty of Engineering Chulalongkorn University 254 Phayathai Road Pathumwan Bangkok10330 Thailand

ISBN: (纸本)9781665444125

The operation of most wastewater treatment systems is an open-loop system. There is limited feedback control of membrane bioreactors (MBR) which makes it impossible to regulate the quality of the treated water. The objectives of this paper are twofold. First, we analyze the equilibrium point of the MBR nonlinear model. Second, we utilize output feedback control with state observer and design optimal PID controllers. We determine the optimum equilibrium point and derive a linearized model of MBR. Then, we design the state observer to estimate the non-measurable state using the pole placement method. Both the measurable output and estimated state are fed back through PID controller. The objectives of PID control consist of stabilization and performance improvement. Genetic Algorithm is applied to find the optimal PID parameters that minimize the integral of absolute error and satisfy the specified time-domain criteria. We apply the observer-based PID controller to the linearized model of MBR. Numerical results demonstrate the design of PID controller and the improvement of the closed-loop response and quality of the treated water. © 2021 IEEE

关键词： Bioreactors

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Recent Progress on Al_(2)O_(3)-C Refractories with Low/ultra-low Carbon Content:A Review

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China's Refractories 2022年第1期31卷 35-44页

作者： ZHAO Chenrui YAN Mingwei LI Hongyu NIU Zhiwang LIANG Baoqing SHANG Junli Henan Rongjin High Temperature Materials Co. Ltd.Weihui 453100China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon *** covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw *** black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special ***/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C *** performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic *** Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.

关键词： low carbon carbon source alumina-carbon refractories ceramic phases aluminum

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