检索结果-内蒙古大学图书馆

Analyzing disinfection by-products yield and mechanisms in UV/Cl2 using response surface methodology and quantitative structure-activity relationship models

引用

Chemosphere 2023年第1期341卷

作者： Yao, Jingjing Li, Haipu Ong, Say Leong Hu, Jiangyong Department of Civil & Environmental Engineering National University of Singapore 1 Engineering Drive 2 Singapore 117576 Singapore Pillar of Engineering Product Development Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Center for Environment and Water Resources College of Chemistry and Chemical Engineering Central South University Changsha410083 China Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety Changsha410083 China NUS Environmental Research Institute National University of Singapore 5A Engineering Drive 1 Singapore 117411 Singapore

The study aimed to investigate the formation of halogenated disinfection byproducts (DBPs) during applying UV/chlorine (UV/Cl2) and unravel the interactive impacts of critical operational parameters and the mechanisms behind DBPs formation. Response surface methodology and quantitative structure-activity relationship models were developed to evaluate the contribution of electrophilic, nucleophilic, and free radical reactions to the formation of DBPs in UV/Cl2. The study found that Cl2 and its interactions dominated the total DBPs and non-Br-DBPs formation, while Br− and the Cl2–Br− interaction played a decisive role in the Br-DBPs formation. The study also observed significant interactions of Br, Cl2, and pH on chloroform, bromodichloromethane, dichloroacetonitrile, 1,1-dichloro-2-propanone, trichloroactic acid, and chlorodibromoacetic acid formations, while no evident interaction on chloral hydrate, dibromochloromethane, trichloroacetone, dibromoacetic acid, and bromodichloroacetic acid formations. The electrophilic substitution of HOBr mainly controlled the formation of trihalomethanes, and the contribution of nucleophilic, electrophilic, and free radical (•OH, Cl•, Cl2•- and ClO•) reactions depended on the molar ratio of Cl2 to Br, and pH-determined hydrolysis rate constants of DBPs and the types of free radicals. Overall, the response surface methodology and quantitative structure-activity relationship models provided a reference for revealing DBPs formation mechanisms in other disinfection processes. © 2023 Elsevier Ltd

关键词： Rate constants

来源：评论

学校读者我要写书评

暂无评论

Exploring ion-selective electrode materials for enhanced capacitive deionization

Green Energy and Resources

引用

Green Energy and Resources 2023年第4期1卷

作者： Zhao, Xiaoyu Song, Xiuli Yang, Shuo Hou, Yongdan Wang, Yanfei Yang, Hui Ying Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization College of Chemical Engineering and Materials Science Tianjin University of Science and Technology Tianjin 300457 China Pillar of Engineering Product Development Singapore University of Technology and Design 487372 Singapore College of Engineering Kwame Nkrumah University of Science and Technology Ghana

In recent years, ion-selective capacitive deionization (CDI) technology has been used to selectively separate ions from multi-ion composition solutions. Innovative ion-selective electrode materials have been widely used in the fields of recovery of high-value ions and removal of toxic and harmful ions. developments of electrode materials and their structure-chemical activity relationships were reviewed and analyzed. Moreover, anticipatory observations and challenges regarding the future of ion-selective CDI devices are discussed. Ultimately, this comprehensive review aims to provide meaningful insights and directions in the exploration for ideal ion-selective electrode materials, propelling further advancements in CDI systems. © 2023 The Author(s)

关键词： Capacitive deionization (CDI) Electrode materials Ion selectivity Removal of heavy metals Resource recovery

来源：评论

学校读者我要写书评

暂无评论

A New Computational Fluid Dynamics Model to Optimize Sucker Rod Pump Operation and design

A New Computational Fluid Dynamics Model to Optimize Sucker ...

引用

作者： Jalikop, Shreyas V. Scheichl, Bernhard Eder, Stefan J. Hönig, Stefan AC2T research GmbH AC2T research GmbH Technische Universität Wien Institute of Fluid Mechanics and Heat Transfer Austria AC2T research GmbH Technische Universität Wien Institute of Engineering Design and Product Development Austria OMV Exploration and Production GmbH TECH Center and Laboratory

Artificial lift systems are widely used in oil production, of which sucker rod pumps are conceptually among the simpler ones. The reciprocating movement of the plunger triggers the opening and closing of two ball valves, allowing fluid to be pumped to the surface. Their built-in ball valves are subject to long-time erosion and fail as a consequence of this damage mechanism. Understanding the principal damage mechanisms requires a thorough examination of the fluid dynamics during the opening and closing action of these valves. In this article, we present a fluid-structure interaction model that simultaneously computes the fluid flow in the traveling valve (TV), the standing valve (SV), and the chamber of sucker rod pumps during a full pump cycle. The simulations shed light on the causes of valve damage for standard and nonideal operating conditions of the pump. In particular, our simulations based on real pump operating envelopes reveal that the so-called "midcycle valve closure" is likely to occur. Such additional closing and opening events of the valves multiply situations in which the flow conditions are harmful to the individual pump components, leading to efficiency reduction and pump failure. This mechanism, hitherto unreported in the literature, is believed to constitute the primary cause of long-term valve damage. Our finite element method-based computational-fluid-dynamics model can accurately describe the opening and closing cycles of the two valves. For the first time, this approach allows an analysis of real TV speed versus position plots, usually called pump cards. The effects of stroke length, plunger speed, and fluid parameters on the velocity and pressure at any point and time inside the pump can thus be investigated. Identifying the damage-critical flow parameters can help suggest measures to avoid unfavorable operating envelopes in future pump designs. Our flow model may support field operations throughout the entire well life, ranging from improved

关键词： Fluid structure interaction

来源：评论

学校读者我要写书评

暂无评论

Graph Attention-based Reinforcement Learning for Trajectory design and Resource Assignment in Multi-UAV Assisted Communication

arXiv

引用

arXiv 2024年

作者： Feng, Zikai Wu, Di Huang, Mengxing Yuen, Chau School of Information and Communication Engineering Hainan University State Key Laboratory of Marine Resource Utilization in South China Sea Haikou570228 China The Engineering Product Development Pillar Singapore University of Technology and Design 487372 Singapore The Department of Automation Shanghai Jiao Tong University Shanghai200240 China PRISMA Lab University of Naples Federico II Naples80125 Italy The School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore

In the multiple unmanned aerial vehicle (UAV)assisted downlink communication, it is challenging for UAV base stations (UAV BSs) to realize trajectory design and resource assignment in unknown environments. The cooperation and competition between UAV BSs in the communication network leads to a Markov game problem. Multi-agent reinforcement learning is a significant solution for the above decision-making. However, there are still many common issues, such as the instability of the system and low utilization of historical data, that limit its application. In this paper, a novel graph-attention multi-agent trust region (GA-MATR) reinforcement learning framework is proposed to solve the multi-UAV assisted communication problem. Graph recurrent network is introduced to process and analyze complex topology of the communication network, so as to extract useful information and patterns from observational information. The attention mechanism provides additional weighting for conveyed information, so that the critic network can accurately evaluate the value of behavior for UAV BSs. This provides more reliable feedback signals and helps the actor network update the strategy more effectively. Ablation simulations indicate that the proposed approach attains improved convergence over the baselines. UAV BSs learn the optimal communication strategies to achieve their maximum cumulative rewards. Additionally, multi-agent trust region method with monotonic convergence provides an estimated Nash equilibrium for the multi-UAV assisted communication Markov *** Codes 68M11 Copyright © 2024, The Authors. All rights reserved.

关键词： Reinforcement learning

来源：评论

学校读者我要写书评

暂无评论

Synergistic Structure Engineering and Electrochemical Activation Modulating Vanadium Oxide Cathode Toward Superior Zinc-Ion Storage

SSRN

引用

SSRN 2024年

作者： Fang, Kan Zhang, Heng Chen, Peng Liu, Jiawang Zhang, Hua-Yu Wei, Zhan Ding, Ling Ye, Xiao-Ai Liu, Yi-Lin Wang, Gui-Gen Yang, Hui Ying Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic Systems School of Materials Science and Engineering Harbin Institute of Technology Shenzhen518055 China School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou215009 China Jiangsu Key Laboratory of Electrochemical Energy-Storage Technologies College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing210016 China Pillar of Engineering Product Development Singapore University of Technology and Design 8 Somapah Road Singapore487372 Singapore Singapore

Aqueous zinc-ion batteries (ZIBs) have emerged as competitive systems for grid-scale energy storage due to their high safety and low cost. However, the progress of high-performance cathode composites limits the practical progress of ZIBs. Herein, a type of cathode material, ammonium cation-inserted and oxygen vacancy co-modulated VO2 (named NVE), was synthesized through the ethylene glycol (EG) sacrificial solvent-assisted structure transformation. The sacrificial solvent promotes the structural transformation of vanadate to ammonium ios-intercalated vanadium oxide and enhances the number of oxygen vacancies in the resulting material. Moreover, the electrochemical activation process was performed for in-situ construction of NH4+-inserted hydrated vanadium oxide (V2O5∙nH2O) material. The electrochemical activation process with high anodic voltage enables multiple electron reactions, increasing the utilization of vanadium elements and achieving high capacity. Additionally, the hydrogen bonding between the V-O host and inserted NH4+ ions enhances the structural integrity, while the vacancies decrease the interaction between the V-O host and inserted Zn2+ ions to boost ion diffusion. Consequently, the resulting cathode demonstrates higher capacity (441 mAh g−1 at 0.1 A g−1), superior cycling durability (85.6% retention over 4000 cycles), and exceptional rate capability (205 mAh g−1 at 20 A g−1). Besides, the fabricated devices based on the activated NVE cathode show decent capacity and excellent flexible stability. Furthermore, the reversible electrochemical Zn2+ storage mechanism upon battery cycling was evaluated by several kinetic measurements and in/ex-situ characterizations. This work provides novel perspectives for the fabrication of advanced cathode materials for superior aqueous ZIBs. © 2024, The Authors. All rights reserved.

关键词： Cathodes

来源：评论

学校读者我要写书评

暂无评论

Block belief propagation algorithm for two-dimensional tensor networks

引用

Physical Review B 2023年第12期108卷 125111-125111页

作者： Chu Guo Dario Poletti Itai Arad Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China Science Mathematics and Technology Cluster Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Engineering Product Development Pillar Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Centre for Quantum Technologies National University of Singapore 117543 Singapore MajuLab CNRS-UNS-NUS-NTU International Joint Research Unit UMI 3654 Singapore Faculty of Physics Technion Haifa 3200003 Israel

Belief propagation is a well-studied algorithm for approximating local marginals of multivariate probability distribution over complex networks, while tensor network states are powerful tools for quantum and classical many-body problems. Building on a recent connection between the belief propagation algorithm and the problem of tensor network contraction, we propose a block belief propagation algorithm for contracting two-dimensional (2D) tensor networks and approximating the ground state of 2D systems. The advantages of our method are threefold: (1) the same algorithm works for both finite and infinite systems; (2) it allows natural and efficient parallelization; and (3) given its flexibility, it would allow us to deal with different unit cells. As applications, we use our algorithm to study the 2D Heisenberg and transverse Ising models, and show that the accuracy of the method is on par with state-of-the-art results.

关键词： Quantum spin models Tensor network methods

来源：评论

学校读者我要写书评

暂无评论

To Adapt Waveforms of Transcutaneous Electrical Stimulation for Effective Relief of Chronic Pain

To Adapt Waveforms of Transcutaneous Electrical Stimulation ...

引用

Rehabilitation Engineering and Assistive Technology (i-CREATe), International Convention on

作者： Ema Oba Ruian Qin Adan Jafet Garcia Inda Zhongchao Zhou Nevrez İmamoğlu Jose Gomez-Tames Shaoying Huang Wenwei Yu Department of Medical Engineering Graduate School of Science and Engineering Chiba University Chiba Japan Technology Laboratory CRESCO LTD. Minato-ku Tokyo Japan Digital Architecture Research Center National Institute of Advanced Industrial Science and Technology Tokyo Japan Graduate School of Science and Engineering Chiba University Chiba Japan Center for Frontier Medical Engineering Chiba University Chiba Japan Engineering Product Development Department Singapore University of Technology and Design Singapore Singapore

ISBN: (数字)9798350355154

ISBN: (纸本)9798350355161

Chronic pain is a serious disease that affects approximately one in five people worldwide. Transcutaneous electrical stimulation (TENS) can be used to stimulate C-nerve to promote endogenous opioid release, thus is expected to be a new method of chronic pain relief. It is a noninvasive, non-drug therapy that can be used at home. One problem is that TENS waveforms are inevitably deformed by the biological tissues between the skin surface and vicinity of the nerves. In addition, this deformation varies depend on the thickness of the individual's biological tissue layer. This deformation of waveforms might strongly affect the efficiency of chronic pain relief, though has not been taken into consideration by any related studies. In our previous study, a multi-layered tissue FEM (Finite Element Method) model was built to inspect the effect of the deformation of various TENS waveforms. However, the computation cost of FEM is too high to calculate a large amount of candidates to find better TENS waveforms. To solve this problem, this study proposed a machine learning based surrogate model for the FEM model and used it as a forward model to enable a gradient based adaption of TENS waveforms. Simulation results showed that the TENS waveforms taking into consideration the deformation could be found. This demonstrated the potential for adapting the TENS waveforms to individual variations.

关键词： Adaptation models Pain Deformation Biological system modeling Computational modeling Simulation Biological tissues Electrical stimulation Finite element analysis Fats

来源：评论

学校读者我要写书评

暂无评论

Slow-varying Dynamics Assisted Temporal Capsule Network for Machinery Remaining Useful Life Estimation

arXiv

引用

arXiv 2022年

作者： Qin, Yan Yuen, Chau Shao, Yimin Qin, Bo Li, Xiaoli Engineering Product Development Pillar Singapore University of Technology and Design 8 Somapah Road 487372 Singapore State Key Laboratory of Mechanical Transmissions Chongqing University Chongqing400044 China School of Mechanical Engineering Inner Mongolia University of Science and Technology Baotou014010 China ASTAR 138632 Singapore

Capsule network (CapsNet) acts as a promising alternative to the typical convolutional neural network, which is the dominant network to develop the remaining useful life (RUL) estimation models for mechanical equipment. Although CapsNet comes with an impressive ability to represent the entities' hierarchical relationships through a high-dimensional vector embedding, it fails to capture the long-term temporal correlation of run-to-failure time series measured from degraded mechanical equipment. On the other hand, the slow-varying dynamics, which reveals the low-frequency information hidden in mechanical dynamical behaviour, is overlooked in the existing RUL estimation models, limiting the utmost ability of advanced networks. To address the aforementioned concerns, we propose a Slow-varying Dynamics assisted Temporal CapsNet (SD-TemCapsNet) to simultaneously learn the slow-varying dynamics and temporal dynamics from measurements for accurate RUL estimation. First, in light of the sensitivity of fault evolution, slow-varying features are decomposed from normal raw data to convey the low-frequency components corresponding to the system dynamics. Next, the long short-term memory (LSTM) mechanism is introduced into CapsNet to capture the temporal correlation of time series. To this end, experiments conducted on an aircraft engine and a milling machine verify that the proposed SD-TemCapsNet outperforms the mainstream methods. In comparison with CapsNet, the estimation accuracy of the aircraft engine with four different scenarios has been improved by 10.17%, 24.97%, 3.25%, and 13.03% concerning the index root mean squared error, respectively. Similarly, the estimation accuracy of the milling machine has been improved by 23.57% compared to LSTM and 19.54% compared to CapsNet. Copyright © 2022, The Authors. All rights reserved.

关键词： Long short-term memory

来源：评论

学校读者我要写书评

暂无评论

Volume Control of Low-Cost Ventilator with Automatic Set-Point Adaptation

Volume Control of Low-Cost Ventilator with Automatic Set-Poi...

引用

European Control Conference (ECC)

作者： Lukas Hewing Marcel Menner Nikolaos Tachatos Marianne Schmid Daners Cosima Du Pasquier Thomas S. Lumpe Kristina Shea Andrea Carron Melanie N. Zeilinger Institute for Dynamic Systems and Control ETH Zurich Zurich Switzerland Product Development Group Zurich ETH Zurich Zurich Switzerland Engineering Design and Computing Laboratory ETH Zurich Zurich Switzerland

This paper considers the control design for a low-cost ventilator that is based on a manual resuscitator bag (also known as AmbuBag) to pump air into the lungs of a patient who is physically unable to breathe. First, it experimentally shows that for accurately tracking tidal volumes, the controller needs to adjust to the individual patient and the different configurations, e.g., hardware or operation modes. Second, it proposes a set-point adaptation algorithm that uses sensor measurements of a flow meter to automatically adapt the controller to the setup at hand. Third, it shows in experiments on a mechanical lung simulator that such an adaptive solution improves the performance of the ventilator for various setups. One objective of this paper is to increase awareness of the need for feedback control using flow measurements in low-cost ventilator solutions in order to automatically adapt to the specific scenario.

关键词： Ventilators Adaptation models Control design Volume measurement Lung Europe Manuals

来源：评论

学校读者我要写书评

暂无评论

Construction Of 1d/2d Core-Shell Structured K6nb10.8o30@Zn2in2s5 As S-Scheme Photocatalysts for Cocatalyst-Free Hydrogen production

SSRN

引用

SSRN 2022年

作者： Wang, Jing Pan, Runhui Yan, Shiye Wang, Rui Niu, Xingyu Hao, Qi Ye, Jilei Wu, Yuping Ying Yang, Hui State Key Laboratory of Materials-oriented Chemical Engineering School of Energy Science and Engineering Nanjing Tech University Jiangsu Nanjing211816 China School of Energy and Environment South East University Jiangsu Nanjing211189 China Pillar of Engineering Product Development Singapore University of Technology and Design Singapore487372 Singapore

Constructing heterostructures is an effective strategy to achieve efficient photocatalysis. The determination of the heterojunction types depends on the photo-induced charge carrier transfer path. Therefore, understanding the charge carrier transfer mechanism of heterojunctions plays an irreplaceable role in guiding the construction of rational heterojunctions. However, it is challenging due to the microscopic nature of charge carrier transfer. Herein, an S-scheme K6Nb10.8O30@Zn2In2S5 (KNbO@ZIS) heterojunction with 1D/2D core-shell structure is designed for improving photocatalytic hydrogen production. KNbO@ZIS exhibits a greatly improved cocatalyst-free hydrogen generation activity (12.35 mmol h-1 g-1) compared to K6Nb10.8O30 (KNbO) and Zn2In2S5 (ZIS) under UV-visible illumination. The improvement of photocatalytic performance is mainly attributed to the suppressed recombination of photogenerated charge carriers by the S-scheme heterojunction. The 1D/2D core-shell structure further accelerates the charge carrier transfer in the photocatalysts. S-scheme heterojunction mechanism is also demonstrated by ex/in situ irradiated X-ray photoelectron spectroscopy and Kelvin probe force microscopy measurements as well as work function calculations. This work provides a powerful strategy for designing novel heterojunction composites. © 2022, The Authors. All rights reserved.

关键词： X ray photoelectron spectroscopy

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：