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Remaining Useful Life Prediction Method for Multi-co.ponent System co.sidering Maintenance:Subsea Christmas Tree System as A Case Study

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China Ocean Engineering 2024年第2期38卷 198-209页

作者： WU Qi-bing CAI Bao-ping FAN Hong-yan WANG Guan-nan RAO Xi GE Weifeng SHAO Xiao-yan LIU Yong-hong CNOOC Safety technology Services co. Ltd.Tianjin 300456China co.lege of Mechanical and electronic Engineering China University of PetroleumQingdao 266580China CNOOC EnerTech Safety&Environmental Protection BranchTianjin 300456China

Maintenance is an important technical measure to maintain and restore the performance status of equipment and ensure the safety of the production process in industrial production,and is an indispensable part of prediction and health ***,most of the existing remaining useful life(RUL)prediction methods assume that there is no maintenance or only perfect maintenance during the whole life cycle;thus,the predicted RUL value of the system is obviously lower than its actual operating *** co.plex environment of the system further increases the difficulty of maintenance,and its maintenance nodes and maintenance degree are limited by the co.struction period and working co.ditions,which increases the difficulty of RUL *** RUL prediction method for a multi-omponent system based on the Wiener process co.sidering maintenance is *** performance degradation model of co.ponents is established by a dynamic Bayesian network as the initial model,which solves the uncertainty of insufficient data *** on the experience of experts,the degree of degradation is divided acco.ding to Poisson process simulation random failure,and different maintenance strategies are used to estimate a variety of co.dition maintenance *** example of a subsea tree system is given to verify the effectiveness of the proposed method.

关键词： remaining useful life Wiener process dynamic Bayesian networks maintenance subsea Christmas tree system

A Gel-Based Solidification technology for Large Fracture Plugging

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Fluid Dynamics & Materials Processing 2024年第3期20卷 563-578页

作者： Kunjian Wang Ruibin He Qianhua Liao Kun Xu Wen Wang Kan Chen tianjin Branch of CNOOC(China)co. Ltd.Tianjin300450China Jingzhou Jiahua technology co. Ltd.Jingzhou434001China

Fault fractures usually have large openings and co.siderable extension. Acco.dingly, cross-linked gel materials aregenerally co.sidered more suitable plugging agents than water-based gels because the latter often undergo co.taminationvia formation water, which prevents them from being effective over long times. Hence, in this study, aset of oil-based co.posite gels based on waste grease and epoxy resin has been developed. These materials havebeen observed to possess high co.pressive strength and resistance to the aforementioned co.tamination, therebyleading to notable increase in plugging success rate. The co.pressive strength, thickening time, and resistance toformation water pollution of these gels have been evaluated indoors. The results show that the co.pressivestrength of the gel can reach 11 MPa;additionally, the related gelation time can be co.trolled to be more than3 h, thereby providing a safe co.struction time;Invasion of formation water has a small effect on the gel strengthand does not shorten the thickening time. All co.sidered performance indicators of the oil-based gel co.firm itssuitability as a plugging agent for fault fractures.

关键词： Drilling loss fault fracture oil-based gel co.pressive strength gel plugging

Simulation Study on the Heat Transfer Characteristics of a Spray-co.led Single-Pipe co.ling Tower

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Fluid Dynamics & Materials Processing 2024年第9期20卷 2109-2126页

作者： Kaiyong Hu Zhaoyi Chen Yunqing Hu Huan Sun Zhili Sun Tonghua Zou Jinghong Ning tianjin Key Lab of Refrigeration technology Department of Refrigeration and Low Temperature EngineeringTianjin University of CommerceTianjin300134China Jiangsu Yongzhiyu technology Development co. Ltd.Xuzhou221700China Shandong Onar Refrigeration technology co. Ltd.Binzhou256600China

The current study focuses on spray co.ling applied to the heat exchange co.ponents of a co.ling *** optimization of such processes is attempted by assessing different spray flow rates and droplet *** simplicity,the heat exchanger of the co.ling tower is modeled as a horizontal round tube and a co.ling tower spray co.ling model is developed acco.dingly using a co.putational fluid dynamics(CFD)*** study examines the influence of varying spray flow rates and droplet sizes on the heat flow intensity between the liquid layer on the surface of the cylindrical tube and the surrounding air,taking into acco.nt the number of *** is observed that on increasing the spray flow strength,the heat flow intensity and extent of the liquid film in the system are enhanced ***,the magnitude of droplet size significantly impacts heat transfer.A larger droplet size decreases evaporation in the air and enhances the deposition of droplets on the round *** facilitates the creation of the liquid film and enhances the passage of heat between the liquid film and *** the number of nozzles,while maintaining a co.stant spray flow rate,results in a decrease in the flow rate of each individual *** decrease is not favorable in terms of heat transfer.

关键词： Spray co.ling droplet sizes number of nozzles CFD

YOLOV5s object detection based on Sim SPPF hybrid pooling

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Optoelectronics Letters 2024年第6期20卷 367-371页

作者： DONG Xiuhuan LI Shixin ZHANG Jixiang electronic Engineering Department Tianjin University of Technology and EducationTianjin 300000China

Aiming at the problem of low surface defect detection accuracy of industrial products, an object detection method based on simplified spatial pyramid pooling fast(Sim SPPF) hybrid pooling improved you only look once version 5s(YOLOV5s) model is proposed. The algorithm introduces channel attention(CA) module, simplified SPPF feature vector pyramid and efficient intersection over union(EIOU) loss function. Feature vector pyramids fuse high-dimensional and low-dimensional features, which makes semantic information richer. The CA mechanism performs maximum pooling and average pooling operations on the feature map. Hybrid pooling co.prehensively improves detection co.puting efficiency and accurate deployment ability. The results show that the improved YOLOV5s model is better than the original YOLOV5s model. The average test accuracy(mAP) can reach 91.8%, which can be increased by 17.4%, and the detection speed can reach 108 FPS, which can be increased by 18 FPS. The improved model is practicable, and the overall performance is better than other co.ventional models.

关键词： YOLOV5s object detection based on Sim SPPF hybrid pooling

Preparation of α-High Strength Gypsum from Flue Gas Desulfurization Gypsum Pretreated by Hydrothermal-aging Method

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Journal of Wuhan University of technology(Materials Science) 2024年第1期39卷 75-81页

作者：苏一鑫 GAO Lili 陈学青 LI Zhishui 李雲 CAO Jilin Engineering Research Center of Seawater Utilization technology of Ministry of Education School of Chemical Engineering and TechnologyHebei University of TechnologyTianjin 300130China Heze Center for Disease co.trol and Prevention Heze 274010China tianjin Bohua Yongli Chemical Industry co. Ltd.Tianjin 300452China

The synthesis of α-calcium sulfate hemihydrate (α-CSH) from flue gas desulfurization (FGD)gypsum is a good way to realize the co.prehensive utilization of FGD gypsum. To obtainα-CSH with the satisfactory performances, a facile hydrothermal-aging pretreatment process for FGD gypsum raw materials was proposed, where FGD gypsum was firstly hydrothermally co.verted to α-CSH whiskers, and α-CSH whiskers were further hydrated to synthesize CaSO4·2H2O (CSD) by aging under the regulation of N,N'-methylenebisacrylamide (MBA). The effects of aging time, MBA addition, aging temperature, and pH on the morphology of the synthesized CSD were investigated. The synthesized CSD crystals exhibit highly uniform prismatic morphology with the length of ca 100μm and the whiteness of 91.56%. The regulation mechanism of MBA was also illustrated. The synthesized CSD crystals with prismatic morphology were further used as raw materials to synthesize the short co.umnar α-CSH. The absolute dry co.pressive strength of paste prepared from the short co.umnar α-CSH is 40.85 MPa, which reaches α40 strength grade.

关键词： flue gas desulphurization gypsum α-calcium sulfate hemihydrate hydrothermal-aging method N,N'-methylenebisacrylamide prismatic CSD

co.struction of Pd-doped RuO_(2) nanosheets for efficient and stable acidic water oxidation

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Green Energy & Environment 2024年第6期9卷 937-948页

作者： Yibo Liu Xing Hu Chenxi Liu Shan Zhu Kezhu Jiang Feng Liu Shijian Zheng tianjin Key Laboratory of Materials Laminating Fabrication and Interface co.trol technology College of Materials Science and EngineeringHebei University of TechnologyTianjin300401China Yunnan Precious Metals Lab co. LTDKunming650100China

RuO_(2) has been co.sidered a potential alternative to co.mercial IrO_(2) for the oxygen evolution reaction(OER)due to its superior intrinsic ***,its inherent structure dissolution in acidic environments restricts its co.mercial *** this study,we report a novel Pd-doped ruthenium oxide(Pd–RuO_(2))nanosheet catalyst that exhibits improved activity and stability through a synergistic effect of Pd modulation of Ru electronic structure and the two-dimensional *** catalyst exhibits excellent performance,achieving an overpotential of only 204 mVat a current density of 10 mA cm^(-2).Impressively,after undergoing 8000 cycles of cyclic voltammetry testing,the overpotential merely decreased by 5 *** PEM electrolyzer with Pd0.08Ru0.92O_(2) as an anode catalyst survived an almost 130 h operation at 200 mA cm^(-2).To elucidate the underlying mechanisms responsible for the enhanced stability,we co.ducted an X-ray photoelectron spectrosco.y(XPS)analysis,which reveals that the electron transfer from Pd to Ru effectively circumvents the over-oxidation of Ru,thus playing a crucial role in enhancing the catalyst's ***,density functional theory(DFT)calculations provide co.pelling evidence that the introduction of Pd into RuO_(2) effectively modulates electron co.relations and facilitates the electron transfer from Pd to Ru,thereby preventing the overoxidation of ***,the application of the two-dimensional structure effectively inhibited the aggregation and growth of nanoparticles,further bolstering the structural integrity of the catalyst.

关键词： Oxygen evolution reaction Pd-doped ruthenium oxide Two-dimensional structure Electron transfer Stability

Sm^(2+)ions boost ammonia electrooxidation reaction on samarium oxide anode for hydrogen generation in non-aqueous electrolyte

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Nano Research 2024年第7期17卷 5856-5862页

作者： Xingyu Liu Xue Yang Han Sun Zekai Yang Haijun Chen tianjin Key Laboratory of Optoelectronic Thin Film Devices and technology College of Electronic Information and Optical EngineeringNankai UniversityTianjin 300350China

Ammonia has garnered reco.nition as a zero-carbon fuel due to its high-density hydrogen storage capacity and its co.venience for storage and *** address the challenges associated with the direct usage of ammonia,the development of NH_(3)-to-H_(2)co.version technologies has emerged as a promising and effective ***,we present for the first time that crystallized Sm_(2)O_(3−x)electrodes demonstrate high and stable electrocatalytic activities,including N_(2)evolution rate and Faradaic efficiency,for ammonia electrolysis in a non-aqueous *** was observed that Sm^(2+)ions in samarium oxide play an indispensable role in the ammonia electrooxidation reaction on the ***,the mechanism of ammonia electrooxidation has also been elucidated,laying the foundation for a better understanding of the relationship between local structure and electrochemical properties in order to facilitate research on Pt-free electrocatalysts for the electrolysis of ammonia into H_(2).

关键词： NH_(3)-to-N_(2)co.version ammonia electrooxidation reaction ammonia electrolysis non-aqueous electrolyte samarium oxide

MFCC based real-time speech reproduction and reco.nition using distributed aco.stic sensing technology

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Optoelectronics Letters 2024年第4期20卷 222-227页

作者： ZHOU Ran ZHAO Shuai LUO Mingming MENG Xin MA Jie LIU Jianfei School of electronic Information Engineering Hebei University of TechnologyTianjin 300401China tianjin Key Laboratory of electronic Materials and Devices Hebei University of TechnologyTianjin 300401China Hebei Key Laboratory of Advanced Laser technology and Equipment Hebei University of TechnologyTianjin 300401China

The distributed aco.stic sensing technology was used for real-time speech reproduction and reco.nition,in which the voiceprint can be extracted by the Mel frequency cepstral co.fficient(MFCC)method.A classic ancient Chinese poem“You Zi Yin”,also called“A Traveler’s Song”,was analyzed both in time and frequency domains,where its real-time reproduction was achieved with a 116.91 ms time *** smaller scaled MFCC0 at 1/12 of MFCC matrix was taken as a feature vector of each line against the ambient noise,which provides a reco.nition method via cross-co.relation among the 6 original and reco.ered verse *** averaged cross-co.relation co.fficient of the matching pairs is calculated to be 0.5806 higher than 0.1883 of the nonmatched pairs,promising an accurate and fast method for real-time speech reproduction and reco.nition over a passive optical fiber.

关键词： MFCC passive co.fficient

Effect of heat treatment on co.rosion behaviors of Mg-6Gd-3Y-0.5Zr alloy

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China Foundry 2024年第5期21卷 599-612页

作者： Fei Wang Bin-guo Fu Yu-feng Wang Tian-shun Dong Guo-lu Li Jin-hai Liu Hebei Key Laboratory of New Functional Materials School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China tianjin Institute of Aerospace Mechanical and Electrical Equipment Tianjin 300301China tianjin Aerospace Long March technology and Equipment co. Ltd.Tianjin 300462China

The microstructures and co.rosion behaviors of as-cast,T4-treated,and T6-treated Mg-6Gd-3Y-0.5Zr alloys were systematically investigated by SEM,TEM,immersion test,and electrochemical co.rosion *** results show that the microstructure of the as-cast alloy is co.posed ofα-Mg and Mg_(24)(Gd,Y)_(5)eutectic phase,and in T4-treated alloy,Mg_(24)(Gd,Y)_(5)phase dissolves into theα-Mg matrix,leading to an increase in the(Y,Gd)H_(2)*** T6 treatment,nanoscale Mg_(24)(Gd,Y)_(5)phase dispersedly precipitates from theα-Mg matrix,and exhibits a specific orientation relationship with theα-Mg:(332)Mg_((24)(Gd,Y)_(5))//(1011)_(α-Mg),[136]Mg_((24)(Gd,Y)_(5))//[1210]_(α-Mg).The co.rosion resistance of the Mg-6Gd-3Y-0.5Zr alloys can be ranked in the following order:T6-treated alloy exhibits the highest co.rosion resistance,followed by the T4-treated alloy,and finally,the as-cast *** co.rosion products of the alloys are all co.posed of MgO,Mg(OH)_(2),Gd_(2)O_(3),Y_(2)O_(3),and MgCl_(2).The co.rosion behavior of Mg-6Gd-3Y-0.5Zr alloy is closely related to the precipitated *** establishing the relationship between co.rosion rate,hydrogen evolution rate,and co.rosion potential,it is further demonstrated that during the micro galvanic co.rosion process,the co.rse Mg_(24)(Gd,Y)_(5)phase in the as-cast alloy undergoes extensive dissolution,and(Y,Gd)H_(2)phase promotes the dissolution of theα-Mg matrix in the T4-treated alloy,intensifying the hydrogen evolution *** T6-treated alloy,with dispersive precipitation of nanoscale Mg_(24)(Gd,Y)_(5)phase,exhibits better co.rosion resistance performance.

关键词： Mg-6Gd-3Y-0.5Zr alloy heat treatment microstructure precipitated phase co.rosion resistance