AIEMs
233535946
Bi functional side chain architecture tuned amphoteric ion exchange membranes for high performance vanadium redox flow batteries
Abstract The blended amphoteric membranes possessed a reducing cation exchange capacity with increasing the anion exchange capacity. Bi functional side chain type polymers are conducive to have both high cation exchange capacity and high anion exchange capacity at the same time, and further enhance ion conductivity of amphoteric ion exchange membranes (AIEMs) Herein, novel side chain type AIEMs are prepared via ring opening metathesis polymerization of norbornene possessing the advantages of yielding easily modified molecular architectures, simple and controllable polymerization, and producing the membranes with high chemical stability. To avoid the occurrence of excess water swelling arising from the increased zwitterionic groups, hydrophobic spacers (alkyl chain (CH2)6 were introduced to be situated between the aromatic main chain and ionic groups. This unique structure favors ion clusters to be aggregated and thus forms highly ordered water channels so that the protons can be efficiently transported along the center of channels and possess excellent proton conductivity. In addition, the ion crosslinking interactions enhance the mechanical stability of AIEMs. The resultant AIEM (1/2) exhibits a higher ion conductivity of 7.58 x 10 2 S cm 1 and vanadium ion permeability of 0.21 x 10 9 cm2 s 1 at room temperature. Based on these good properties, the vanadium redox flow batteries (VRBs) with prepared membranes and Nafion 212 were tested. The energy efficiency (EE) of VRBs with AIEM (1/2) still reaches 84.76% at the current density of 160 mA cm 2, which is better than that with Nafion 212 (76.26% Moreover, the EE of VRBs with AIEM (1/2) is 82.11% after 200 cycles, indicating that the prepared membranes possess a good stability.
Zhenfeng He Hu Liu Qian Hu Nithesh Naik Zhanhu Guo
225131147
An overview of amphoteric ion exchange membranes for vanadium redox flow batteries
Abstract Vanadium redox flow battery (VRB) as the most promising large scale electrical energy storage units, has attracted extensive attention. Amphoteric ion exchange membrane (AIEM) as the core part of VRB, separates electrolyte on both sides of electrolytic tank and conducts H+ The AIEM with cation and anion groups possesses excellent performances, such as high ion conductivity (s) low vanadium ion permeability (PVn+ relative stability and low cost. However, the performance of AIEM directly depends on the chemical structure of polymers. In addition to ensuring foundational physical performance, ion selectivity of AIEM is significant since the crossover of vanadium ion with various valences may reduce the battery capacity. In this paper, AIEMs for VRB and their chemical structures as well as synthesis approaches to realize all kinds of high performing AIEMs are reviewed. The current trend and future direction of prospective materials for the VRB separators are documented in detail as well.
Chao Wang Zhenfeng He Rajib Das Binbin Dong Xiao-feng Xie Zhanhu Guo
232382940
Polymer Membranes for All Vanadium Redox Flow Batteries: A Review
Redox flow batteries such as the all vanadium redox flow battery (VRFB) are a technical solution for storing fluctuating renewable energies on a large scale. The optimization of cells regarding performance, cycle stability as well as cost reduction are the main areas of research which aim to enable more environmentally friendly energy conversion, especially for stationary applications. As a critical component of the electrochemical cell, the membrane influences battery performance, cycle stability, initial investment and maintenance costs. This review provides an overview about flow battery targeted membranes in the past years (1995 2020) More than 200 membrane samples are sorted into fluoro carbons, hydro carbons or N heterocycles according to the basic polymer used. Furthermore, the common description in membrane technology regarding the membrane structure is applied, whereby the samples are categorized as dense homogeneous, dense heterogeneous, symmetrical or asymmetrically porous. Moreover, these properties as well as the efficiencies achieved from VRFB cycling tests are discussed, e.g. membrane samples of fluoro carbons, hydro carbons and N heterocycles as a function of current density. Membrane properties taken into consideration include membrane thickness, ion exchange capacity, water uptake and vanadium ion diffusion. The data on cycle stability and costs of commercial membranes, as well as membrane developments, are compared. Overall, this investigation shows that dense anion exchange membranes (AEM) and N heterocycle based membranes, especially poly(benzimidazole) (PBI) membranes, are suitable for VRFB requiring low self discharge. Symmetric and asymmetric porous membranes, as well as cation exchange membranes (CEM) enable VRFB operation at high current densities. Amphoteric ion exchange membranes (AIEM) and dense heterogeneous CEM are the choice for operation mode with the highest energy efficiency.
Membranes
Dennis Duerkop Hartmut Widdecke Carsten Schilde Ulrich Kunz Achim Schmiemann
233786555
Modelling of Microwave Multi Frequency Emission and Backscatter by a Community Land Active Passive Microwave Radiative Transfer Modelling Platform (CLAP)
Emission and backscattering at different frequencies have varied responses to soil physical processes (e.g. moisture redistribution, freeze thaw) and vegetation growing/senescencing. Combing the use of active and passive microwave multi frequency signals may provide complementary information, which can be used to better retrieve soil moisture, and vegetation biomass and water content for ecological applications. To this purpose, a Community Land Active Passive Microwave Radiative Transfer Modelling Platform (CLAP) was adopted in this study to simulate both emission (T B and backscatter (s 0 in which the CLAP is backboned by the TorVergata model for modelling vegetation scattering, and an air to soil transition model (ATS) (accounting for surface dielectric roughness) integrated with the Advanced Integral Equation Model (AIEM) for modelling soil surface scattering. The accuracy of CLAP was assessed by both ground based and spaceborne measurements, and the former was from the deployed microwave radiometer/scatterometer observatory at Maqu site on an alpine meadow over the Tibetan plateau. Specifically, for the passive case, simulated T B (emissivity multiplied by effective temperature) were compared to the ground based ELBARA III L band observations, as well as Cband Advanced Microwave Scanning Radiometer 2 (AMSR2) and L band Soil Moisture Active Passive (SMAP) observations. For the active case, simulated s 0 were compared to the groundbased scatterometer Cand L bands observations, and C band Sentinel and L band Phased Array type L band Synthetic Aperture Radar 2 (PALSAR 2) observations. This study is expected to contribute to improving the soil moisture retrieval accuracy for dedicated microwave sensor configurations.
Hong-Kang Zhao Yijian Zeng Bob Z Su Jan Hofste
235511363
Radar Backscattering Over Sea Surface Oil Emulsions: Simulation and Observation
Oils floating on the sea surface can be observed as `dark' patches on radar images since the backscattered signals from the contaminated area are reduced in two dominant ways. First, oil slicks could damp short gravity and capillary waves on the sea surface responsible for backscattering energy. Second, the oil covered sea surface permittivity decreases significantly if the oil film is sufficiently thick or mixed with seawater, i.e. oil emulsion. In this article, the geometry of the oil covered sea surface is accounted for by the damping of sea waves, which is described by the model of local balance (MLB) combined with the sea wave spectrum. The radar backscattering is predicted by the advanced integral equation method (AIEM) model. The reflection coefficients are calculated based on a layered medium model to analyze the impact of oil thickness and emulsions on the radar scattering. Numerical simulations demonstrate that: 1) the sensitivity to oil thickness and water content of the oil spills increases when the radar frequency increases; 2) the backscattering signals exhibit a nonlinear behavior with respect to oil thickness; and 3) high wind speed can generally narrow the difference between the radar backscattering from the clean and oil covered sea surface, while the incidence angle has little effect. Numerical simulations are then compared with the multifrequency synthetic aperture radar observations acquired during the Gulf of Mexico Deepwater Horizon (DWH) oil spill accident and the 2011 Norwegian Clean Seas Association for Operating Companies (NOFO) oil on water exercise. Comparison results show that it is possible to estimate the oil thickness at reasonably good accuracy.
Tingyu Meng Xiaofeng Yang Kun Shan Chen Ferdinando Nunziata Dengfeng Xie Andrea Buono
234204384
Soil Moisture Retrieval during the Wheat Growth Cycle Using SAR and Optical Satellite Data
The objective of this paper is to propose a combined approach for the high precision mapping of soil moisture during the wheat growth cycle based on synthetic aperture radar (SAR) (Radarsat 2) and optical satellite data (Landsat 8) For this purpose, the influence of vegetation was removed from the total backscatter by using the modified water cloud model (MWCM) which takes the vegetation fraction (fveg) into account. The VV/VH polarization radar backscattering coefficients database was established by a numerical simulation based on the advanced integrated equation model (AIEM) and the cross polarized ratio of the Oh model. Then the empirical relationship between the bare soil backscattering coefficient and both the soil moisture and the surface roughness was developed by regression analysis. The surface roughness in this paper was described by using the effective roughness parameter and the combined roughness form. The experimental results revealed that using effective roughness as the model input instead of in situ measured roughness can obtain soil moisture with high accuracy and effectively avoid the uncertainty of roughness measurement. The accuracy of soil moisture inversion could be improved by introducing vegetation fraction on the basis of the water cloud model (WCM) There was a good correlation between the estimated soil moisture and the observed values, with a root mean square error (RMSE) of about 4.14% and the coefficient of determination (R2) about 0.7390.
Fengkai Lang Nanshan Zheng
236253634
Artificial intelligence on economic evaluation of energy efficiency and renewable energy technologies
Abstract The energy sector currently faces growing challenges related to increasing demand, efficiency, a lack of analytics required for optimal management, and changing supply and demand patterns. Renewable energy technologies such as Energy forecasting, energy efficiency, and energy accessibility are the key factors that incorporate Artificial intelligence. In this paper, the Artificial Intelligence based useful evaluation model (AIEM) has been proposed for forecasting renewable energy and energy efficiency impact on the economy. This study intended to analyze, compare and build a model utilizing artificial intelligence and specific economic indicators significant in economic prediction regarding renewable energy. AI approaches that can be employed to overcome different challenges, including selecting the best consumer to react for the attributes and desires, competitive pricing, scheduling, and managing facilities, incentivizing demand response participants, and compensating them equally and economically. The proposed model can help enhance energy efficiency to 97.32% and improve renewable energy resource utilization.
Yuhang Hu Marimuthu Karuppiah
236237927
Novel ether free sulfonated poly(biphenyl) tethered with tertiary amine groups as highly stable amphoteric ionic exchange membranes for vanadium redox flow battery
Abstract The development of cost effective, ion selective and highly stable non fluorinated hydrocarbon membranes is crucial to the vanadium redox flow battery (VRFB) Herein, we report a facile approach to designing a novel ether free amphoteric ionic exchange membrane (AiEM) grafted with long flexible alkyl side chains with zwitterionic groups, prepared by superacid catalyzed polycondensation with post modification. Both FTIR and H1NMR spectra confirm the polymer's chemical structure. An acid base interaction that can form between sulfonic group and tertiary amine group contributes to the high stability, low swelling ratio and vanadium ion permeability of the AiEM. Owing to the unique amphoteric structure and connected ion channels, optimized TA15 SPBP membrane achieves a high proton conductivity of 0.116 S cm 1 25 together with superb ion selectivity of 14.7 x 105 S min cm 3 compared to that of Nafion212 membrane. Consequently, the VRFB assembled with the TA15 SPBP membrane exhibits superior coulombic/energy efficiencies of 99.1%/87% at 80 mA cm 2 with respect to Nafion212 (92.9%/78.2% Importantly, the highly stable ether free backbone and acid base interaction greatly improve the structural stability of the membrane. During an 1188 cycling test, the TA15 SPBP membrane keeps almost unchanged efficiencies at 80 mA cm 2 with excellent capacity retention (80.5% in comparison with Nafion212 (11.3% during the first 200 cycles, thus demonstrating the promising prospects for VRFB applications.
Jianfeng Xu Pan Li Jun-Rui Wang Qingqing Cheng Zhouying Yue
231618674
Adaptive Controller of PEMFC Output Voltage Based on Ambient Intelligence Large Scale Deep Reinforcement Learning
In this article, an adaptive Proportion integration (PI) controller for varying the output voltage of a proton exchange membrane fuel cell (PEMFC) is proposed. The PI controller operates on the basis of ambient intelligence large scale deep reinforcement learning. It functions as a coefficient tuner based on an ambient intelligence exploration multi delay deep deterministic policy gradient (AIEM DDPG) algorithm. This algorithm is an improvement on the original deep deterministic police gradient (DDPG) algorithm, which incorporates ambient intelligence exploration. The DDPG algorithm serves as the core, and the AIEM DDPG algorithm runs on a variety of deep reinforcement learning algorithms, including soft actor critic (SAC) deep deterministic policy gradient (DDPG) proximal policy optimization (PPO) and double deep Q network (DDQN) algorithms, to attain distributed exploration in the environment. In addition, a classified priority experience replay mechanism is introduced to improve the exploration efficiency. Clipping multi Q learning, policy delayed updating, target policy smooth regularization and other methods are utilized to solve the problem of Q value overestimation. A model free algorithm with good global searching ability and optimization speed is demonstrated. Simulation results show that the AIEM DDPG adaptive PI controller attains better robustness and adaptability, as well as a good control effect.
IEEE Access
Jiawen Li Tao Yu Bo Yang
233309606
Deep carious lesions management in children and adolescents: a questionnaire survey among dentists practicing paediatric dentistry in France.
INTRODUCTION While many questionnaire surveys have been undertaken worldwide to investigate practices toward deep carious lesion (DCL) management in adults, very few are related to children and adolescents. The present cross sectional study aimed to assess DCL management in children and adolescents among dentists practicing paediatric dentistry in France (Fr DPPDs) The secondary objective was to compare practices between Fr DPPDs and dentists registered in the European Academy of Paediatric Dentistry (EAPD) METHODS A questionnaire was electronically administrated to members of the CEOP (College des Enseignants en Odontologie Pediatrique) the SFOP (Societe Francaise d'Odontologie Pediatrique) and the EAPD. Descriptive analyses, Chi square and McNemar tests, ANOVA, crude and adjusted binary logistic regression analyses were performed. RESULTS A total of 99 Fr DPPDs and 146 EAPD members answered the questionnaire. Among the Fr DPPDs, the preferred caries removal (CR) methods were the complete CR in one step for primary teeth and mature permanent teeth (respectively, 70% and 48% and in two steps for immature permanent teeth (39% EAPD members were more likely, than Fr DPPDs, to choose selective CR versus complete CR in primary teeth (odds ratio 2.60; 95% CI 1.39 4.85) Moreover, for primary or immature permanent teeth, general practitioners were less likely to choose selective CR than specialists and exclusive practitioners in paediatric dentistry, (p 0.001) CONCLUSION Tooth type [primary, permanent (immature or mature) seemed to influence DCL management. Fr DPPS should prioritise pulpal vitality when managing DCL.
European archives of paediatric dentistry official journal of the European Academy of Paediatric Dentistry
Michele Muller-Bolla Elody Aiem A M Velly Sophie Domejean