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Liquid Metal-Based Self-Healable and Elastic Conductive Fiber in Complex Operating Conditions 被引量:2
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作者 Yin Zhou Yingying Zhu +4 位作者 Zuan Hu Xiaoying Yang Pengkun Yang Lu Huang Yingpeng Wu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第6期297-304,共8页
Flexible conductive fibers are essential for wearable electronics and smart electronic textiles.However,in complex operating conditions,conductive fibers will inevitably fracture or damage.Herein,we have developed an ... Flexible conductive fibers are essential for wearable electronics and smart electronic textiles.However,in complex operating conditions,conductive fibers will inevitably fracture or damage.Herein,we have developed an elastic conductive self-healable fiber(C-SHF),of which the electrical and mechanical properties can efficiently heal in a wide operating range,including room temperature,underwater,and low temperature.This advantage can be owed to the combination of reversible covalent imine bond and disulfide bond,as well as the instantaneous self-healing ability of liquid metal.The C-SHF,with stretchability,conductivity stability,and universal self-healing properties,can be used as an electrical signal transmission line at high strain and under different operating conditions.Besides,C-SHF was assembled into a double-layer capacitor structure to construct a self-healable sensor,which can effectively respond to pressure as a wearable motion detector. 展开更多
关键词 complex operating conditions elastic conductive fiber liquid metal SELF-HEALING
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Feature Extraction Method Based on Pseudo-Wigner-Ville Distribution for Rotational Machinery in Variable Operating Conditions 被引量:9
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作者 WANG Huaqing LIKe +1 位作者 SUN Hao CHEN Peng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第4期661-668,共8页
In the case of fault diagnosis for roller bearings, the conventional diagnosis approaches by using the time interval of energy impacts in time-frequency distribution or the pass-frequencies are based on the assumption... In the case of fault diagnosis for roller bearings, the conventional diagnosis approaches by using the time interval of energy impacts in time-frequency distribution or the pass-frequencies are based on the assumption that machinery operates under a constant rotational speed. However, when the rotational speed varies in the broader range, the pass-frequencies vary with the change of rotational speed and bearing faults cannot be identified by the interval of impacts. Researches related to automatic diagnosis for rotational machinery in variable operating conditions were quite few. A novel automatic feature extraction method is proposed based on a pseudo-Wigner-Ville distribution (PWVD) and an extraction of symptom parameter (SP). An extraction method for instantaneous feature spectrum is presented using the relative crossing information (RCI) and sequential inference approach, by which the feature spectrum from time-frequency distribution can be automatically, sequentially extracted. The SPs are considered in the frequency domain using the extracted feature spectrum to identify among the conditions of a machine. A method to obtain the synthetic symptom parameter is also proposed by the least squares mapping (LSM) technique for increasing the diagnosis sensitivity of SP. Practical examples of diagnosis for bearings are given in order to verify the effectiveness of the proposed method. The verification results show that the features of bearing faults, such as the outer-race, inner-race and roller element defects have been effectively extracted, and the proposed method can be used for condition diagnosis of a machine under the variable rotational speed. 展开更多
关键词 feature extraction pseudo-wigner-ville distribution variable operating condition sequential diagnosis
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Influences of fluid physical properties,solid particles,and operating conditions on the hydrodynamics in slurry reactors 被引量:2
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作者 He Yang Aqiang Chen +4 位作者 Shujun Geng Jingcai Cheng Fei Gao Qingshan Huang Chao Yang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第4期51-71,共21页
Slurry reactors are popular in many industrial processes,involved with numerous chemical and biological mixtures,solid particles with different concentrations and properties,and a wide range of operating conditions.Th... Slurry reactors are popular in many industrial processes,involved with numerous chemical and biological mixtures,solid particles with different concentrations and properties,and a wide range of operating conditions.These factors can significantly affect the hydrodynamic in the slurry reactors,having remarkable effects on the design,scale-up,and operation of the slurry reactors.This article reviews the influences of fluid physical properties,solid particles,and operating conditions on the hydrodynamics in slurry reactors.Firstly,the influence of fluid properties,including the density and viscosity of the individual liquid and gas phases and the interfacial tension,has been reviewed.Secondly,the solid particle properties(i.e.,concentration,density,size,wettability,and shape)on the hydrodynamics have been discussed in detail,and some vital but often ignored features,especially the influences of particle wettability and shape,as well as the variation of surface tension because of solid concentration alteration,are highlighted in this work.Thirdly,the variations of physical properties of fluids,hydrodynamics,and bubble behavior resulted from the temperature and pressure variations are also summarized,and the indirect influences of pressure on viscosity and surface tension are addressed systematically.Finally,conclusions and perspectives of these notable influences on the design and scale-up of industrial slurry reactors are presented. 展开更多
关键词 Multiphase reactors Fluid physical properties PARTICLE operating conditions Bubble column Airlift loop reactor
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Boosting lithium batteries under harsh operating conditions by a resilient ionogel with liquid-like ionic conductivity 被引量:2
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作者 Le Yu Qing Liu +6 位作者 Libin Wang Songtao Guo Qiaomei Hu Yaqian Li Xiwei Lan Zhifang Liu Xianluo Hu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第11期408-414,I0009,共8页
New chemistries are being developed to increase the capacity and power of rechargeable batteries. However, the risk of safety issues increases when high-energy batteries using highly active materials encounter harsh o... New chemistries are being developed to increase the capacity and power of rechargeable batteries. However, the risk of safety issues increases when high-energy batteries using highly active materials encounter harsh operating conditions. Here we report on the synthesis of a unique ionogel electrolyte for abuse-tolerant lithium batteries. A hierarchically architected silica/polymer scaffold is designed and fabricated through a facile soft chemistry route, which is competent to confine ionic liquids with superior uptake ability (92.4 wt%). The monolithic ionogel exhibits high conductivity and thermal/mechanical stability, featuring high-temperature elastic modulus and dendrite-free lithium cycling. The Li/LiFePO_(4) pouch cells achieve outstanding cyclability at different temperatures up to 150 ℃, and can sustain cutting, crumpling, and even coupled thermal–mechanical abuses. Moreover, the solid-state lithium batteries with LiNi_(0.60)Co_(0.20)Mn_(0.20)O_(2), LiNi_(0.80)Co_(0.15)Al_(0.05)O_(2), and Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) cathodes demonstrate excellent cycle performances at 60 ℃. These results indicate that the resilient and high-conductivity ionogel electrolyte is promising to realize high-performance lithium batteries with high energy density and safety. 展开更多
关键词 Ionogel electrolytes Lithium batteries SAFETY Harsh operating conditions CYCLABILITY
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Effects of Operating Conditions on the Catalytic Performance of HZSM-5 Zeolites in n-Pentane Cracking 被引量:2
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作者 Hou Xu Zhao Liu +3 位作者 Ma Zhenzhou Chen Bochong Feng Jingyuan Cui Tingting 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2021年第1期67-75,共9页
In this work,n-pentane catalytic cracking over HZSM-5 zeolites was studied at 650°C under atmosphere pressure.A particular attention was paid to the measurement of n-pentane conversion,light olefins production,pr... In this work,n-pentane catalytic cracking over HZSM-5 zeolites was studied at 650°C under atmosphere pressure.A particular attention was paid to the measurement of n-pentane conversion,light olefins production,product distribution,coke deposit,etc.Several indexes were defined to evaluate the effects of operating conditions on the catalytic performance of HZSM-5 zeolites.It was found that decreasing the weight hourly space velocity,increasing the reactant partial pressure,and increasing the carrier gas flow rate could inhibit C-H bond breaking and enhance the C-C bond breaking and hydride transfer reactions,leading to reduced alkenes selectivity,which suppressed the formation of external coke and alleviated the deactivation of HZSM-5 zeolites.It was deduced that the catalytic stability of HZSM-5 zeolites was improved at the cost of alkenes selectivity.Compared with decreasing the weight hourly space velocity and increasing the reactant partial pressure,increasing the carrier gas flow rate could enhance the diffusion process and protect alkenes from being consumed in coke formation in order to improve the catalytic stability of HZSM-5 zeolites with less reduction of alkenes selectivity. 展开更多
关键词 operating conditions HZSM-5 zeolites catalytic performance n-pentane cracking light olefins
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Effect of Operating Conditions on Olefin Distribution in FCC Gasoline as Part of an Olefin Reduction Process 被引量:1
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作者 Ouyang Fusheng Pei Xu +2 位作者 Zhao Xuhong Liu Xuan Weng Huixin (Research Institute of Petroleum Processing,East China University of Science and Technology,Shanghai 200237) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2010年第4期34-42,共9页
The effects of operating conditions on the distribution of olefins in the FCC gasoline, obtained during catalytic cracking reaction in the presence of the GOR-Q catalyst and conventional MLC-500 catalyst, have been st... The effects of operating conditions on the distribution of olefins in the FCC gasoline, obtained during catalytic cracking reaction in the presence of the GOR-Q catalyst and conventional MLC-500 catalyst, have been studied in detail. The test results showed that the GOR-Q catalyst could obviously reduce the content of several kinds of olefins in FCC gasoline. Olefins in the FCC gasoline consist mainly of C5- C7 compounds, that are composed of C=C bond with normal or mono- branched chains. The reduction of gasoline olefin content could be achieved by decreasing the content of above-mentioned olefins. Lower reaction temperature, lower weight hourly space velocity (WHSV) and higher catalyst to oil ratio would help to reduce the content of olefins with a C = C double bond, normal olefins, mono-branched-chain olefins and diolefins. To decrease the loss of gasoline octane number, the operation for olefin reduction should be firstly focused on increasing the catalyst to oil ratio. 展开更多
关键词 operating conditions FCC gasoline olefin CATALYST
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Enhanced exergy cost optimization of operating conditions in FCCU main fractionator
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作者 Chonglin Zhong Yi Zheng +1 位作者 Shenghu Xu Shaoyuan Li 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第8期1750-1757,共8页
Exergy indicates the maximal energy that can do work effectively. Different from optimization of product quality or calculation of generic energy conservation in most previous studies, the application of exergy analys... Exergy indicates the maximal energy that can do work effectively. Different from optimization of product quality or calculation of generic energy conservation in most previous studies, the application of exergy analysis and exergy cost optimization in petrochemical industry is of great economic and environmental significance. Based on the main fractionator in Jiujiang Petrochemical Complex No. 2 FCCU, an enhanced exergy cost optimization under different operating conditions by adjusting set points of temperature and valves opening degree for flow control is studied in this paper in order to reduce exergy cost and improve the quality of energy. A steadystate optimization algorithm to enhance exergy availability and an objective function comprehensively considering exergy loss are proposed. On the basis of ensuring the quality of petroleum products, the economic benefits can be improved by optimizing the controllable variables due to the fact that exergy cost is decreased. 展开更多
关键词 EXERGY Optimization of operating conditions FRACTIONATOR FCCU Exergy Cost
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Fault diagnosis of diesel engine valve clearance under variable operating condition based on soft interval SVM
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作者 Jiang Zhinong Lai Yuehua +2 位作者 Mao Zhiwei Zhang Jinjie Lai Zehua 《High Technology Letters》 EI CAS 2021年第2期111-120,共10页
The fault detection and diagnosis of diesel engine valve clearance can effectively improve the availability and safety of diesel engine and have extremely important value and significance.Diesel engines generally oper... The fault detection and diagnosis of diesel engine valve clearance can effectively improve the availability and safety of diesel engine and have extremely important value and significance.Diesel engines generally operate in various stable operating conditions,which have important influence on the fault diagnosis.However,many fault diagnosis methods have been put forward under specific stable operating condition based on vibration signal.As the result of great impact caused by operating conditions,corresponding diagnosis models cannot deal with the fault diagnosis under different operating conditions with required accuracy.In this paper,a fault diagnosis of diesel engine valve clearance under variable operating condition based on soft interval support vector machine(SVM)is proposed.Firstly,the fault features with weak condition sensitivity have been extracted according to the influence analysis of fault on vibration signal.Moreover,soft interval constraint has been applied to SVM algorithm to reduce the random influence of vibration signal on fault features.In addition,different machine learning algorithms based on different feature sets are adopted to conduct the fault diagnosis under different operating conditions for comparison.Experimental results show that the proposed method is applicable for fault diagnosis under variable operating condition with good accuracy. 展开更多
关键词 diesel engine fault diagnosis operating condition support vector machine(SVM)
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Ferroresonance at Open Phase Operating Conditions of Power Transformers
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作者 Hani Obeid 《Journal of Energy and Power Engineering》 2012年第10期1714-1717,共4页
The reliability of electric supply to consumers is one of the most important factors that determine the requirements imposed on modem utility companies. This paper presents the results of investigation by computer sof... The reliability of electric supply to consumers is one of the most important factors that determine the requirements imposed on modem utility companies. This paper presents the results of investigation by computer software of the overvoltages resulting from a ferroresonance conditions in MV networks at open phase operating condition with and without connection to earth on source and load sides of distribution transformer. This overvoltage may reach 4.2 pu on one of the HV side of transformer unswitched phases. The results of the study show that ferroresonance overvoltage may be controlled by replacing fuses with circuit breakers on HV side to ensure switching-off all phases. Insertion of resistor or reactor in the neutral of source and loadsides of the transformer with 5% active load will help in suppressing overvoltages. 展开更多
关键词 FERRORESONANCE OVERVOLTAGE open phase operating condition non-linear inductance.
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Operating conditions combination analysis method of optimal water management state for PEM fuel cell 被引量:1
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作者 Wenxin Wan Yang Yang +5 位作者 Yang Li Changjun Xie Jie Song Zhanfeng Deng Jinting Tan Ruiming Zhang 《Green Energy and Intelligent Transportation》 2023年第4期28-42,共15页
The water content of proton exchange membrane fuel cells(PEMFCs)affects the transport of reactants and the conductivity of the membrane.Effective water management measures can improve the performance and extend the li... The water content of proton exchange membrane fuel cells(PEMFCs)affects the transport of reactants and the conductivity of the membrane.Effective water management measures can improve the performance and extend the lifespan of the fuel cell.The water management state of the stack is influenced by various external operating conditions,and optimizing the combination of these conditions can improve the water management state within the stack.Considering that the stack's internal resistance can reflect its water management state,this study first establishes an internal resistance-operating condition model that considers the coupling effect of temperature and humidity to determine the variation trend of total resistance and stack humidity with single-factor operating conditions.Subsequently,the water management state optimization method based on the ANN-HGPSO algorithm is proposed,which not only quantitatively evaluates the influence weights of different operating conditions on the stack's internal resistance but also efficiently and accurately obtains the optimal combination of five operating conditions:working temperature,anode gas pressure,cathode gas pressure,anode gas humidity,and cathode gas humidity to achieve the optimal water management state in the stack,within the entire range of current densities.Finally,the response surface experimental results of the stack also validate the effectiveness and accuracy of the ANN-HGPSO algorithm.The method mentioned in this article can provide effective strategies for efficient water management and output performance optimization control of PEMFC stacks. 展开更多
关键词 PEMFC Water management statue Internal resistance-operating condition model operating condition optimization Response surface method
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Parametric Study of Operating Conditions on Performances of a Solid Oxide Electrolysis Cell
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作者 CHEN Hanming WANG Jingyi XU Xinhai 《Journal of Thermal Science》 SCIE EI CAS CSCD 2023年第6期1973-1988,共16页
The operating conditions greatly affect the electrolysis performance and temperature distribution of solid oxide electrolysis cells(SOECs).However,the temperature distribution in a cell is hard to determine by experim... The operating conditions greatly affect the electrolysis performance and temperature distribution of solid oxide electrolysis cells(SOECs).However,the temperature distribution in a cell is hard to determine by experiments due to the limitations of in-situ measurement methods.In this study,an electrochemical-flow-thermal coupling numerical cell model is established and verified by both current-voltage curves and electrochemical impedance spectroscopy(EIS)results.The electrolysis performance and temperature distribution under different working conditions are numerically analyzed,including operating temperature,steam and hydrogen partial pressures in the fuel gas,inlet flow rate and inlet temperature of fuel gas.The results show that the electrolysis performance improves with increasing operating temperature.Increasing steam partial pressure improves electrolysis performance and temperature distribution uniformity,but decreases steam conversion rate.An inappropriately low hydrogen partial pressure reduces the diffusion ability of fuel gas mixture and increases concentration impedance.Although increasing the flow rate of fuel gas improves electrolysis performance,it also reduces temperature distribution uniformity.A lower airflow rate benefits temperature distribution uniformity.The inlet temperature of fuel gas has little influence on electrolysis performance.In order to obtain a more uniform temperature distribution,it is more important to preheat the air than the fuel gas. 展开更多
关键词 solid oxide electrolysis cell electrolysis performance temperature distribution operating conditions EIS(electrochemical impedance spectroscopy)
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Aero-Hydro-Elastic-Servo Modeling and Dynamic Response Analysis of A Monopile Offshore Wind Turbine Under Different Operating Scenarios
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作者 XIE Shuang-yi GAO Jian +3 位作者 LI Yong-ran JIANG Shu-xin ZHANG Cheng-lin HE Jiao 《China Ocean Engineering》 SCIE EI CSCD 2024年第3期379-393,共15页
This paper constructs a coupled aero-hydro-elastic-servo simulation framework for a monopile offshore wind turbine(OWT).In this framework,a detailed multi-body dynamics model of the monopile OWT including the gearbox,... This paper constructs a coupled aero-hydro-elastic-servo simulation framework for a monopile offshore wind turbine(OWT).In this framework,a detailed multi-body dynamics model of the monopile OWT including the gearbox,blades,tower and other components(nacelle,hub,bedplate,etc.)has been explicitly established.The effects of pile−soil interaction,controller and operational conditions on the turbine dynamic responses are studied systematically in time domain and frequency domain.The results show that(1)a comprehensive drivetrain model has the capability to provide a more precise representation of the complex dynamic characteristics exhibited by drivetrain components,which can be used as the basis for further study on the dynamic characteristics of the drivetrain.(2)The pile−soil interaction can influence the wind turbine dynamic responses,particularly under the parked condition.(3)The effect of the pile−soil interaction on tower responses is more significant than that on blade responses.(4)The use of the controller can substantially affect the rotor characteristics,which in turn influences the turbine dynamic responses.(5)The tower and blade displacements under the operational condition are much larger than those under the parked condition.The model and methodology presented in this study demonstrate potential for examining complex dynamic behaviors of the monopile OWTs.To ensure accuracy and precision,it is imperative to construct a detailed model of the wind turbine system,while also taking into account simulation efficiency. 展开更多
关键词 offshore wind turbine(OWT) pile−soil interaction dynamic response parked condition operating condition
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Thermal Performance of a Micro Heat Pipe Array for Battery Thermal Management Under Special Vehicle-Operating Conditions 被引量:1
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作者 Chengning Yao Dan Dan +4 位作者 Yangjun Zhang Yueqi Wang Yuping Qian Yuying Yan Weilin Zhuge 《Automotive Innovation》 CSCD 2020年第4期317-327,共11页
The thermal management of battery systems is critical for maintaining the energy storage capacity,life span,and thermal safety of batteries used in electric vehicles,because the operating temperature is a key factor a... The thermal management of battery systems is critical for maintaining the energy storage capacity,life span,and thermal safety of batteries used in electric vehicles,because the operating temperature is a key factor affecting battery performance.Excessive temperature rises and large temperature differences accelerate the degradation rate of such batteries.Currently,the increasing demand for fast charging and special on-vehicle scenarios has increased the heat dissipation requirements of battery thermal management systems.To address this demand,this work proposes a novel micro heat pipe array(MHPA)for thermal management under a broadened research scope,including high heat generation rates,large tilt angles,mild vibration,and distributed heat generation conditions.The experimental results indicate that the temperature difference is maintained 3.44°C at a large heat generation of 50 W for a limited range of tilt angles.Furthermore,a mild vehicle vibra-tion condition was found to improve temperature uniformity by 3.3°C at a heat generation of 10 W.However,the use of distributed heat sources results in a temperature variation of 3.88°C,suggesting that the heat generation distribution needs to be considered in thermal analyses.Understanding the effects of these special battery-operating conditions on the MHPA could significantly contribute to the enhancement of heat transfer capability and temperature uniformity improvement of battery thermal management systems based on heat pipe technologies.This would facilitate the realization of meeting the higher requirements of future battery systems. 展开更多
关键词 Battery thermal management Thermal performance Micro heat pipe array operating conditions
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Effects of operating conditions and pre-densification on the torrefaction products of sorghum straw
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作者 Xuanzuo Liu Zonglu Yao +3 位作者 Hongbin Cong Lixin Zhao Lili Huo Jinchun Song 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第4期219-225,共7页
The effects of operating conditions and pre-densification on the torrefaction performance parameters and the properties of the torrefied sorghum straw were studied.A full-factor experiment was performed on a fixed tub... The effects of operating conditions and pre-densification on the torrefaction performance parameters and the properties of the torrefied sorghum straw were studied.A full-factor experiment was performed on a fixed tube furnace,in which sorghum straw powder and pellets were heated to 230℃,260℃,280℃ and 300℃ at 2.5℃/min,5℃/min and 7.5℃/min,respectively.The pyrolysis characteristics of the sorghum straw torrefied under various operating conditions were complemented by thermogravimetric analysis.It was observed that the high temperature led to the high calorific value of the torrefied sorghum straw with an acceptable mass and energy yield.The sorghum straw torrefied at a temperature above 280℃ had a higher heating value(HHV)that was comparable to that of the low rank coal while maintaining its energy yield above 85%.The results suggested that temperature was an important factor determining the properties of the torrefied products,and the heating rate would affect the internal temperature of the torrefied biomass by affecting the heat transfer during the torrefaction.The energy densification index of the pellets decreased uniformly as the heating rate increased proportionally,indicating that pre-densification can be used as a potential method to solve the heat transfer delay in the fixed reactors at high heating rates,especially for high temperatures. 展开更多
关键词 TORREFACTION pre-densification pyrolysis characteristics operating condition sorghum straw heat transfer
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Agglomeration behavior of petal-shaped cerium carbonate with different operating conditions
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作者 Yan-Hong Hu Liang Xu +4 位作者 Mei Li Xue-Feng Wang Zhao-Gang Liu Mi-Tang Wang Xiao-Wei Zhang 《Rare Metals》 SCIE EI CAS CSCD 2018年第2期154-160,共7页
Agglomeration phenomenon can often be observed during the fabrication process of petal-shaped, nano-sized Ce2(CO3)3 powders. This kind of powder was produced by liquid-phase precipitation method with the template ag... Agglomeration phenomenon can often be observed during the fabrication process of petal-shaped, nano-sized Ce2(CO3)3 powders. This kind of powder was produced by liquid-phase precipitation method with the template agent of polyallylamine hydrochloride (PAH). In this study, the effects of the polymer concentration, pH value, and stirring speed on the agglomeration phe- nomenon of cerium carbonate were investigated. On the condition that the concentration of PAH is 0.9 g·L^-1, the pH value of the adjusting solution is 3-4, the final pH value is 8-10, and the stirring speed is 300-400 r·min^-1, it is found that the agglomeration phenomenon of Ce2(CO3)3 particles can be greatly prevented and the regular petal- shaped particles are formed. 展开更多
关键词 Cerium carbonate AGGLOMERATION Polyallylamine hydrochloride operating conditions
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Elimination of Partial Overloading of Generators Under Unbalanced Operating Conditions of Power Systems
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作者 Sudhakar Reddy Sama Subrata Paul Sunita Halder Nee Dey 《CSEE Journal of Power and Energy Systems》 SCIE 2016年第1期81-87,共7页
Unbalanced operating condition in a power system can cause partial overloading of the generators in the network,a condition where one or two of the three phases of the generator become overloaded even if the total 3-p... Unbalanced operating condition in a power system can cause partial overloading of the generators in the network,a condition where one or two of the three phases of the generator become overloaded even if the total 3-phase power output of the generator is within its specified limit.Partial overloading of generators beyond certain limits is undesirable and must be avoided.Distribution systems are often subjected to highly unbalanced operating conditions.Introduction of distributed generations(DGs),therefore,has rendered today’s distribution systems quite susceptible to this problem.Mitigation of this problem requires the issue to be addressed properly during analysis,operation and planning of such systems.Analysis,operation and planning of power networks under unbalanced operating condition require 3-phase load flow study.The existing methods of 3-phase load flow are not equipped to take into account any limit on the loadings of the individual phases of the generators.In the present work,a methodology based on NewtonRaphson(N-R)3-phase load flow with necessary modifications is proposed.The proposed methodology is able to determine the safe loading limits of the generators,and,can be adopted for operation and planning of power networks under unbalanced operating conditions to overcome the above difficulties.Test results on IEEE-37 bus feeder network are presented to demonstrate the effectiveness of the proposed method. 展开更多
关键词 Newton Raphson 3-phase load flow partial overloading of generators unbalanced operating condition of power systems
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Robust Damage Detection and Localization Under Complex Environmental Conditions Using Singular Value Decomposition-based Feature Extraction and One-dimensional Convolutional Neural Network
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作者 Shengkang Zong Sheng Wang +3 位作者 Zhitao Luo Xinkai Wu Hui Zhang Zhonghua Ni 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第3期252-261,共10页
Ultrasonic guided wave is an attractive monitoring technique for large-scale structures but is vulnerable to changes in environmental and operational conditions(EOC),which are inevitable in the normal inspection of ci... Ultrasonic guided wave is an attractive monitoring technique for large-scale structures but is vulnerable to changes in environmental and operational conditions(EOC),which are inevitable in the normal inspection of civil and mechanical structures.This paper thus presents a robust guided wave-based method for damage detection and localization under complex environmental conditions by singular value decomposition-based feature extraction and one-dimensional convolutional neural network(1D-CNN).After singular value decomposition-based feature extraction processing,a temporal robust damage index(TRDI)is extracted,and the effect of EOCs is well removed.Hence,even for the signals with a very large temperature-varying range and low signal-to-noise ratios(SNRs),the final damage detection and localization accuracy retain perfect 100%.Verifications are conducted on two different experimental datasets.The first dataset consists of guided wave signals collected from a thin aluminum plate with artificial noises,and the second is a publicly available experimental dataset of guided wave signals acquired on a composite plate with a temperature ranging from 20℃to 60℃.It is demonstrated that the proposed method can detect and localize the damage accurately and rapidly,showing great potential for application in complex and unknown EOC. 展开更多
关键词 Ultrasonic guided waves Singular value decomposition Damage detection and localization Environmental and operational conditions One-dimensional convolutional neural network
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Generation of input spectrum for electrolysis stack degradation test applied to wind power PEM hydrogen production
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作者 Yanhui Xu Guanlin Li +1 位作者 Yuyuan Gui Zhengmao Li 《Global Energy Interconnection》 EI CSCD 2024年第4期462-474,共13页
Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current... Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current research on the durability of proton exchange membrane electrolyzers is insufficient.Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks.In this study,the operating condition spectrum of an electrolysis stack degradation test cycle was proposed.Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference,a fluctuation output power sample set was formed.The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected.Dimensionality reduction of the operating data was performed using principal component analysis.Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm.Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example,the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed.After preliminary simulation analysis,the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack.This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy. 展开更多
关键词 Hydrogen production by electrolysis of water Wind power Proton exchange membrane electrolyzer Gaussian mixture model Cyclic operating condition
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Numerical Investigation on Thermal Performance of Two-Phase Immersion Cooling Method for High-Power Electronics
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作者 Liqun Zhou Weilin Yang +1 位作者 Chaojie Li Shi Lin 《Frontiers in Heat and Mass Transfer》 EI 2024年第1期157-173,共17页
The power density of electronic components grows continuously,and the subsequent heat accumulation and temperature increase inevitably affect electronic equipment’s stability,reliability and service life.Therefore,ac... The power density of electronic components grows continuously,and the subsequent heat accumulation and temperature increase inevitably affect electronic equipment’s stability,reliability and service life.Therefore,achieving efficient cooling in limited space has become a key problem in updating electronic devices with high performance and high integration.Two-phase immersion is a novel cooling method.The computational fluid dynamics(CFD)method is used to investigate the cooling performance of two-phase immersion cooling on high-power electronics.The two-dimensional CFD model is utilized by the volume of fluid(VOF)method and Reynolds StressModel.Lee’s model was employed to calculate the phase change rate.The heat transfer coefficient along the heatedwalls and the shear-lift force on bubbles are calculated.The simulation data are verified with the literature results.The cooling performance of different coolants has been studied.The results indicate that the boiling heat transfer coefficient can be enhanced by using a low boiling point coolant.The methanol is used as the cooling medium for further research.In addition,the mass flow rate and inlet temperature are investigated to assess the thermal performance of twophase immersion cooling.The average temperature of the high-power electronics is 80℃,and the temperature difference can be constrained to 8℃.Meanwhile,the convective heat transfer coefficient reaches 2740 W/(m2・℃)when the inlet temperature is 50℃,and the mass flow rate is 0.3 kg/s.In conclusion,the results demonstrated that two-phase immersion cooling has provided an effective method for the thermal management of high-power electronics. 展开更多
关键词 Immersion cooling operating condition high-power electronics thermal management
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Optimal reaction conditions for pyridine synthesis in riser reactor 被引量:3
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作者 Shuaishuai Zhou Zelong Liu +4 位作者 Xiao Yan Qin Di Mengxi Liu Chunxi Lu Guangzhou Jin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第7期1499-1507,共9页
Pjridine has been generally synthesized by aldehydes and ammonia in a turbulent fluidized-bed reactor. In this paper, a novel riser reactor was proposed for pyridine synthesis. Experiment result showed that the yield ... Pjridine has been generally synthesized by aldehydes and ammonia in a turbulent fluidized-bed reactor. In this paper, a novel riser reactor was proposed for pyridine synthesis. Experiment result showed that the yield of pyridine and 3-picoline decreased, but the selectivity of pyridine over 3-picoline increased compared to turbulent fluidized-bed reactor. Based on experimental data, a modified kinetic model was used for the determination of optimal operating condition for riser reactor. The optimal operating condition of riser reactor given by this modified model was as follows: The reaction temperature of 755 K, catalyst to feedstock ratio (CTFR) of 87, residence timeof3.8sandinitialacetaldehydesconcentrationof0.0029mol.L-1 (acetaldehydes to formaldehydes ratio by mole (ATFR) of 0.65 and ammonia to aldehydes ratio by mole (ATAR) of 0.9, water contention of 63wt% (formaldehyde solution)). 展开更多
关键词 Pyridine synthesis Riser reactor Optimal operating condition
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