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Overview of automotive engine friction and reduction trends-Effects of surface, material, and lubricant-additive technologies

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Friction 2016年第1期4卷 1-28页

作者： Victor W.WONG simon c.tung Massachusetts Institute of Technology Cambridge MA 02139 USA Vanderbilt chemicals LLc Norwalk CT 06856 USA

The increasing global environmental awareness, evidenced by recent worldwide calls for control of climate change and greenhouse emissions, has placed significant new technical mandates for automotives to improve engine efficiency, which is directly related to the production of carbon dioxide, a major greenhouse gas. Reduction of parasitic losses of the vehicle, powertrain and the engine systems is a key component of energy conservation. For engine efficiency improvement, various approaches include improvements in advanced combustion systems, component system design and handling—such as down-sizing, boosting, and electrification—as well as waste heat recovery systems etc. Among these approaches, engine friction reduction is a key and relatively cost-effective approach, which has been receiving significant attention from tribologists and lubricant-lubrication engineers alike. In this paper, the fundamentals of friction specific to the environments of engine components tribology are reviewed, together with discussions on the impact of developing vehicle powertrain technologies, surface and material technologies, as well as lubricant and additive technologies on promises of continuing friction and wear reduction trends. The international accords on climate change require further gains in fuel efficiency and energy sustainability from all industry sectors including those in the automotive and the broader internal combustion engine industries, and the latter encompass off-highway, power generation, marine, and rail industries as well. This paper focsuses on friction reduction in mainly automotive engines, however. The paper starts with a clarification of the common descriptors of mechanical losses and friction in the engine, followed by the topic of lubrication fundamentals such as lubrication regimes. Then the lubrication of the contacting surfaces in each of the major engine subsystems is discussed in turn. These subsystems include the piston assembly: ring-pack/liner,

关键词： powertrain tribology automotive lubricants additive formulation mechanical design surface coatings and textures friction wear

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含MoDTc全配方发动机油与渗氮活塞环的摩擦学配合性

含MoDTC全配方发动机油与渗氮活塞环的摩擦学配合性

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第七届全国摩擦学大会

作者：马亚军李生华金元生王玉琮 simon c.tung 清华大学摩擦学国家重点实验室清华大学摩擦学国家重点实验室清华大学摩擦学国家重点实验室通用汽车公司通用汽车公司

在250℃下,利用SRV高温摩擦磨损试验机研究了含MoDTc摩擦改进剂的GF-2和GF-3全配方矿物基发动机油与不锈钢渗氮活塞环/铸铁缸套摩擦副的摩擦学性能。结果表明:含MoDTc的GF-2发动机油润滑时摩擦系数下降速度较快,而含MoDTc的GF-3发动机... 详细信息

在250℃下,利用SRV高温摩擦磨损试验机研究了含MoDTc摩擦改进剂的GF-2和GF-3全配方矿物基发动机油与不锈钢渗氮活塞环/铸铁缸套摩擦副的摩擦学性能。结果表明:含MoDTc的GF-2发动机油润滑时摩擦系数下降速度较快,而含MoDTc的GF-3发动机油润滑时摩擦系数更低（最低达0．03）;表层结构不同但成分和硬度相近的渗氮活塞环具有相似的摩擦学特性。

关键词： MoDTc 节能发动机油活塞环摩擦磨损

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Data-driven diagnosis of high temperature PEM fuel cells based on the electrochemical impedance spectroscopy: Robustness improvement and evaluation

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Journal of Energy chemistry 2024年第9期96卷 544-558页

作者： Dan Yu Xingjun Li Samuel simon Araya simon Lennart Sahlin Vincenzo Liso Department of Energy Aalborg UniversityAalborg 9220Denmark Walker Department of Mechanical Engineering The University of Texas at AustinAustinTX 78712USA Materials Research and Technology Development Luxembourg Institute of Science and Technology(LIST)4422 BelvauxLuxembourg

Utilizing machine learning techniques for data-driven diagnosis of high temperature PEM fuel cells is beneficial and meaningful to the system durability. Nevertheless, ensuring the robustness of diagnosis remains a critical and challenging task in real application. To enhance the robustness of diagnosis and achieve a more thorough evaluation of diagnostic performance, a robust diagnostic procedure based on electrochemical impedance spectroscopy (EIS) and a new method for evaluation of the diagnosis robustness was proposed and investigated in this work. To improve the diagnosis robustness: (1) the degradation mechanism of different faults in the high temperature PEM fuel cell was first analyzed via the distribution of relaxation time of EIS to determine the equivalent circuit model (EcM) with better interpretability, simplicity and accuracy;(2) the feature extraction was implemented on the identified parameters of the EcM and extra attention was paid to distinguishing between the long-term normal degradation and other faults;(3) a Siamese Network was adopted to get features with higher robustness in a new embedding. The diagnosis was conducted using 6 classic classification algorithms—support vector machine (SVM), K-nearest neighbor (KNN), logistic regression (LR), decision tree (DT), random forest (RF), and Naive Bayes employing a dataset comprising a total of 1935 collected EIS. To evaluate the robustness of trained models: (1) different levels of errors were added to the features for performance evaluation;(2) a robustness coefficient (Roubust_c) was defined for a quantified and explicit evaluation of the diagnosis robustness. The diagnostic models employing the proposed feature extraction method can not only achieve the higher performance of around 100% but also higher robustness for diagnosis models. Despite the initial performance being similar, the KNN demonstrated a superior robustness after feature selection and re-embedding by triplet-loss method, which sug

关键词： PEM fuel cell Data-driven diagnosis Robustness improvement and evaluation Electrochemical impedance spectroscopy

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Regional trends and petrologic factors inhibit global interpretations of zircon trace element compositions

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Geoscience Frontiers 2024年第5期15卷 300-307页

作者： Nick M.W.Roberts christopher J.Spencer Stephen Puetz c.Brenhin Keller simon Tapster Geochronology and Tracers Facility British Geological SurveyNottingham NG125GGUK Department of Geological Sciences and Geological Engineering Queen’s UniversityKingstonOntarioCanada Atkinson Dr Suite 704HonoluluHI 96814USA Department of Earth Sciences Dartmouth CollegeHanoverNew HamphireUSA

The trace element composition of zircon reveals information about the melt that they are derived from,as such,detrital zircon trace element compositions can be used to interrogate melt compositions,and thus the evolution of the continental crust in time and ***,we present a global database of detrital zircon compositions and use it to test whether average global trends for five common petrogenetic proxies truly represent secular changes in continental *** demonstrate that the secular trend is broadly comparable across continental regions for Ti-in-zircon temperatures,but for other trace element ratios interrogated,secular trends are highly variable between continental *** trace element ratios result from multiple petrologic variables,we argue that these petrogenetic proxies can be overinterpreted if projected to global geologic *** particular,we caution against the interpretation of crustal thickness from trace elements in zircon,and we argue that our results negate current hypotheses concerning secular changes in crustal thickness.

关键词： Detrital zircon Trace elements Secular change Eu anomaly crustal thickness

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Experimental and Numerical Analysis of a PcM-Integrated Roof for Higher Thermal Performance of Buildings

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Journal of Thermal Science 2024年第2期33卷 522-536页

作者： simon François RUIZ-VALERO Letzai GIRARD Aymeric GALLEGUILLOS Hector centro de Desarrollo Urbano Sustentable(cEDEUS) Pontificia Universidad Católica de Chile7500000SantiagoChile Facultad de ciencias e Ingeniería Pontificia Universidad Católica Madre y Maestra(PUCMM)10103Santo DomingoDominican Republic LMGc IMT Mines AlesUniv MontpellierCNRS30100AlèsFrance Facultad de Ingeniería y ciencias Universidad Adolfo Ibañez2520000Viña del MarChile centro de Desarrollo Energético Antofagasta(cDEA) Universidad de Antofagasta1240000AntofagastaChile

Phase change materials(PcMs) designate materials able to store latent *** change state from solid to liquid over a defined temperature *** process is reversible and can be used for thermo-technical *** present paper aims to study the thermal performance of an inorganic eutectic PcM integrated into the rooftop slab of a test room and analyze its potential for building thermal *** experiment is conducted in two test rooms in Antofagasta(chile) during summer,fall,and *** PcM is integrated into the rooftop of the first test room,while the roof panel of the second room is a sealed air *** work introduces a numerical model,which is built using the finite difference method and used to simulate the rooms' thermal *** thermal simulations of the PcM room are performed for other chilean locations to evaluate and compare the capability of the PcM panel to store latent heat thermal energy in different *** show that the indoor temperature of the PcM room in Antofagasta varies only 21.1℃±10.6℃,while the one of the air-panel room varies 28.3℃±18.5℃.Under the experiment's conditions,the PcM room's indoor temperature observes smoother diurnal fluctuations,with lower maximum and higher minimum indoor temperatures than that of the air-panel *** simulations in other cities show that the PcM panel has a better thermal performance during winter,as it helps to maintain or increase the room temperature by some degrees to reach comfort *** demonstrates that the implementation of such PcM in the building envelope can effectively reduce space heating and cooling needs,and improve indoor thermal comfort in different climates of chile.

关键词： phase change material thermal energy storage building space heating and cooling energy efficiency designbuilder

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Exploring a New Lifetime Distribution for Modelling the Waiting Time of Bank customers

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Journal of Applied Mathematics and Physics 2024年第1期12卷 194-209页

作者： simon A. Ogumeyo Jacob c. Ehiwario Festus c. Opone Department of Mathematics Delta State University of Science and Technology Ozoro Nigeria Department of Statistics University of Delta Agbor Nigeria Department of Statistics Delta State University of Science and Technology Ozoro Nigeria

The fitting of lifetime distribution in real-life data has been studied in various fields of research. With the theory of evolution still applicable, more complex data from real-world scenarios will continue to emerge. Despite this, many researchers have made commendable efforts to develop new lifetime distributions that can fit this complex data. In this paper, we utilized the KM-transformation technique to increase the flexibility of the power Lindley distribution, resulting in the Kavya-Manoharan Power Lindley (KMPL) distribution. We study the mathematical treatments of the KMPL distribution in detail and adapt the widely used method of maximum likelihood to estimate the unknown parameters of the KMPL distribution. We carry out a Monte carlo simulation study to investigate the performance of the Maximum Likelihood Estimates (MLEs) of the parameters of the KMPL distribution. To demonstrate the effectiveness of the KMPL distribution for data fitting, we use a real dataset comprising the waiting time of 100 bank customers. We compare the KMPL distribution with other models that are extensions of the power Lindley distribution. Based on some statistical model selection criteria, the summary results of the analysis were in favor of the KMPL distribution. We further investigate the density fit and probability-probability (p-p) plots to validate the superiority of the KMPL distribution over the competing distributions for fitting the waiting time dataset.

关键词： KM-Transformation Power Lindley Distribution Data Fitting Moments Quantiles

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Transfer learning from synthetic data for open-circuit voltage curve reconstruction and state of health estimation of lithium-ion batteries from partial charging segments

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Energy and AI 2024年第3期17卷 80-97页

作者： Tobias Hofmann Jacob Hamar Bastian Mager simon Erhard Jan Philipp Schmidt chair of Systems Engineering for Electrical Energy Storage University of BayreuthWeiherstraße 26Bayreuth95448BavariaGermany BMW Group Petuelring 130Munich80809BavariaGermany

Data-driven models for battery state estimation require extensive experimental training data,which may not be available or suitable for specific tasks like open-circuit voltage(OcV)reconstruction and subsequent state of health(SOH)*** study addresses this issue by developing a transfer-learning-based OcV reconstruction model using a temporal convolutional long short-term memory(TcN-LSTM)network trained on synthetic data from an automotive nickel cobalt aluminium oxide(NcA)cell generated through a mechanistic model *** data consists of voltage curves at constant temperature,c-rates between c/30 to 1c,and a SOH-range from 70%to 100%.The model is refined via Bayesian optimization and then applied to four use cases with reduced experimental nickel manganese cobalt oxide(NMc)cell training data for higher use *** TL models’performances are compared with models trained solely on experimental data,focusing on different c-rates and voltage *** results demonstrate that the OcV reconstruction mean absolute error(MAE)within the average battery electric vehicle(BEV)home charging window(30%to 85%state of charge(SOc))is less than 22 mV for the first three use cases across all *** SOH estimated from the reconstructed OcV exhibits an mean absolute percentage error(MAPE)below 2.2%for these *** study further investigates the impact of the source domain on TL by incorporating two additional synthetic datasets,a lithium iron phosphate(LFP)cell and an entirely artificial,non-existing,cell,showing that solely the shifting and scaling of gradient changes in the charging curve suffice to transfer knowledge,even between different cell chemistries.A key limitation with respect to extrapolation capability is identified and evidenced in our fourth use case,where the absence of such comprehensive data hindered the TL process.

关键词： Lithium-ion battery State of health estimation Transfer learning OcV curve Partial charging Synthetic data

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Structural,morphological,optical and antibacterial performances of rare earth(Sm)-doped ZnO nanorods

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Journal of Rare Earths 2024年第11期42卷 2119-2127页

作者： A.Ravi J.Samuel S.Sahaya Jude Dhas S.Usharani Turibius simon D.Senthil Kumar S.K.Jasmin Vijitha A.Sivakumar Raju Suresh Kumar c.S.Biju Department of Physics University College of Engineering Department of Physics and Research centre Malankara Catholic College Manonmaniam Sundaranar University Saveetha School of Engineering Saveetha Institute of Medical and Technical SciencesSaveetha University Department of chemistry S.I.V.E.T College Department of Biotechnology Vivekanandha College of Arts and Science for Woman (Autonomous) Department of Physics Vel Tech Rangarajan Dr.Sagunthala R & D Institute of Science and Technology Department of Physics & Research centre Muslim Arts College Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior Institute of GeochemistryChinese Academy of Sciences Department of chemistry College of ScienceKing Saud University Department of Physics St. Alphonsa College of Arts and Science

The significant rise of ultra-violet（UV） radiation and pathogenic infectious bacteria poses a serious threat to global *** researchers' interests are attracted by novel materials with strong UVblocking ability,antibacterial activity and low toxicity to other *** this case,a simple wet chemical method with different annealing temperatures（400,500,and 600℃） was employed to create highly effective rare earth（Sm）-doped ZnO ***（101） plane of wurtzite ZnO shifts towards a lower angle with increasing annealing temperature,according to the X-ray diffraction（XRD） study findings,which additionally establishes the consequence of lattice *** of doublet peaks of Sm 3d(Sm 3d5/2and Sm 3d3/2) in the X-ray photoelectron spectroscopy（XPS） spectrum clearly validates the substitution of Sm3+ions in the 500℃-annealed *** 500℃-annealed nanorods exhibit combined performances of the wide band gap,improved UV absorbance,and vivid green luminescent emission（563 nm）.Additio nally,the nanorods have favorable UV-blocking execution of 96% for UVA at 360 nm,92% for UVB at 320 nm,and 57% for UVc at 225 nm,which is greater than the majority of ZnO-related materials that have been reported up to this *** doping is also appropriate for improving bacterial inhibition against the two studied strains（Escherichia coli and Staphylococcus aureus）,in addition to the intriguing features discussed ***,with maximum inhibition zone diameters of 20±0.72 and 18±0.57 mm,respectively,these nanorods exhibit high inhibitory action against *** and *** bacterial *** rare earth-doped material developed during the current experiment,which was annealed at 500℃,could potentially serve as an effective replacement for UV-blocking and antibacterial material,especially for biomedical applications.

关键词： Wet chemical method rare earth doping Metal oxide UV-Shielding Bacterial inhibition

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Predictors of survival in autoimmune liver disease overlap syndromes

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World Journal of Hepatology 2024年第9期16卷 1269-1277页

作者： Dujinthan Jayabalan Yi Huang Luis calzadilla-Bertot Malik Janjua Bastiaan de Boer John Joseph Wendy cheng simon Hazeldine Briohny W Smith Gerry c MacQuillan Michael c Wallace George Garas Leon A Adams Gary P Jeffrey Medical School University of Western AustraliaNed-lands 6009Western AustraliaAustralia Department of Hepatology Sir Charles Gairdner HospitalNedlands 6009Western AustraliaAustralia Department of Anatomical Pathology PathWest Laboratory MedicineNedlands 6009Western AustraliaAustralia Department of Gastroenterology and Hepatology Royal Perth HospitalPerth 6000Western AustraliaAustralia Department of Gastroenterology and Hepatology Fiona Stanley HospitalMurdoch 6150Western AustraliaAustralia Medical School University of Western AustraliaNedl-ands 6009Western AustraliaAustralia

BAcKGROUND Survival in patients with autoimmune liver disease overlap syndromes(AILDOS)compared to those with single autoimmune liver disease is *** To investigate the survival of patients with AILDOS and assess the accuracy of non-invasive serum models for predicting liver-related *** Patients with AILDOS were defined as either autoimmune hepatitis and primary biliary cholangitis overlap(AIH-PBc)or autoimmune hepatitis and primary sclerosing cholangitis overlap(AIH-PSc)and were identified from three tertiary centres for this cohort ***-related death or transplantation(liver-related mortality)was determined using a population-based data linkage *** scores for liver-related death were compared for accuracy[including liver outcome score(LOS),Hepascore,Mayo Score,model for end-stage liver disease(MELD)score and MELD incorporated with serum sodium(MELD-Na)score].RESULTS Twenty-two AILDOS patients were followed for a median of 3.1 years(range,0.35-7.7).Fourteen were female,the median age was 46.7 years(range,17.8 to 82.1)and median Hepascore was 1(range,0.07-1).At five years post enrolment,57%of patients remained free from liver-related mortality(74%AIH-PBc,27%AIH-PSc).There was no significant difference in survival between AIH-PBc and *** was a significant predictor of liver-related mortality(Pc(n=14)but not AIH-PSc(n=8).A LOS cut-point of 6 discriminated liver-related mortality in AIH-PBc patients(P=0.012,log-rank test,100%sensitivity,77.8%specificity)(Harrell's c-statistic 0.867).The MELD score,MELD-Na score and Mayo Score were not predictive of liver-related mortality in any *** Survival in the rare,AILDOS is *** current study supports the LOS as a predictor of liver-related mortality in AIH-PBc *** trials investigating predictors of survival in AILDOS are required.

关键词： Autoimmune liver disease overlap syndromes Liver outcome score Liver-related death Hepascore Autoimmune hepatitis Primary biliary cholangitis Primary sclerosing cholangitis

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Rekindling *** cooperation

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Beijing Review 2024年第26期67卷 22-23页

作者： Denis simon The Institute for china-America Studies in Washington D.C

chinese President Xi Jinping's recent reply to a letter from Lamont Repollet,/President of Kean University in New Jersey,the U.S.,could not have occurred at a more opportune *** against the backdrop of the 50,000-student initiative announced by President Xi during a visit to the United States in November 2023,the letter emphasized the importance of educational exchanges in building positive bilateral relations,and called on universities in both countries to strengthen cooperation in pursuing ***.

关键词： U.S. letter universities

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