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Influence of structural depth of laser-patterned steel surfaces on the solid lubricity of carbon nanoparticle coatings

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Friction 2023年第7期11卷 1276-1291页

作者： Timothy MACLUCAS Lukas DAUT philipp GRÜtzmacher Maria Agustina GUITAR Volker PRESSER Carsten GACHOT Sebastian SUAREZ Frank MÜCKLICH Chair of Functional Materials Saarland UniversitySaarbrücken 66123Germany Institute for Engineering Design and Product Development TU WienWien 1060Austria INM–Leibniz Institute for New Materials Saarbrücken 66123Germany Department of Materials Science&Engineering Saarland UniversitySaarbrücken 66123Germany Saarene-Saarland Center for Energy Materials and Sustainability Saarbrücken 66123Germany

Carbon nanoparticle coatings on laser-patterned stainless-steel surfaces present a solid lubrication system where the pattern's recessions act as lubricant-retaining *** study investigates the influence of the structural depth of line patterns coated with multi-walled carbon nanotubes(CNTs)and carbon onions(COs)on their respective potential to reduce friction and *** laser interference patterning(DLIP)with a pulse duration of 12 ps is used to create line patterns with three different structural depths at a periodicity of 3.5μm on AISI 304 steel ***,electrophoretic deposition(EPD)is applied to form homogeneous carbon nanoparticle coatings on the patterned *** ball-on-disc experiments are conducted on the as-described surfaces with an alumina counter body at a load of 100 *** results show that the shallower the coated structure,the lower its coefficient of friction(COF),regardless of the particle ***,with a minimum of just below 0.20,CNTs reach lower COF values than COs over most of the testing *** resulting wear tracks are characterized by scanning electron microscopy,transmission electron microscopy,and energy-dispersive X-ray *** friction testing,the CNTs remain in contact,and the immediate proximity,whereas the CO coating is largely *** of structural depth,no oxidation occurs on CNT-coated surfaces,whereas minor oxidation is detected on CO-coated wear tracks.

关键词： solid lubricant coatings carbon nanotubes carbon onions direct laser interference patterning(DLIP)surface structuring electrophoretic deposition(EPD)

Applying ionic liquids as oil additives for gearboxes:Going beyond the state of the art by bridging the nano-scale and component level

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Friction 2023年第6期11卷 1057-1078页

作者： Azhaarudeen ANIFA MOHAMED FARUCK philipp G.GRÜtzmacher Chia-Jui HSU Dominik DWORSCHAK Hsiu-Wei CHENG Markus VALTINER Kristof STAGEL philipp MIKSOVSKY Apurba Ranjan SAHOO Aitor SAINZ MARTINEZ Katharina BICA-SCHRODER Michael WEIGAND Carsten GACHOT Institut für Konstruktionswissenschaften und Produktentwicklung(IKP) Tribology Research DivisionTU WienVienna1060Austria Institut für Angewandte Physik(IAP) Applied Interface Physics research groupTU WienVienna1040Austria Institut für Angewandte Synthesechemie(IAS) Sustainable Organic Synthesis and Catalysis research groupTU WienVienna1060Austria

Ionic liquids(ILs)have been used effectively in many applications for reducing problems related to friction and *** this work,the potential of ILs as an anti-wear and extreme pressure lubricant additive for high load-carrying gearbox applications such as helicopter transmissions has been *** halide-free ILs:P_(8881)(BuO)_(2)PO_(2)^(-)(1)and P_(8881)(MeO)_(2)PO_(2)^(-)(2),which are blended at 5 wt%each into a standard non-additivated FVA2 base oil(BO)are *** solid-liquid interface,friction and load-carrying capacity,and wear(scuffing)behavior are studied on the nano-,lab-,and component-scale,respectively,at a different range of temperature and loading conditions by using the atomic force microscopy(AFM),Schwing-Reib-Verschleiβ(SRV)friction tests,and Brugger tests,as well as forschungsstelle für zahnrader und getriebebau(FZG)back-to-back gear test *** AFM analysis shows nearly no change of adhesion over the full range of studied temperature for the IL blends compared to the ***,IL blends demonstrate a very stable coefficient of friction(COF)of around 0.16,which even decreases with increasing test temperatures ranging from 40 to 120℃.A clear reduction in COF up to 25%is achieved by adding only 5 wt%of the investigated Ils in the BO,and the Brugger tests also show a pronounced enhancement of load-carrying ***,on the component-scale,a significant improvement in gear scuffing performance has been observed for both used IL blends.A detailed characterization of the wear tracks from the SRV friction tests via the transmission electron microscopy(TEM)revealed the formation of a phosphate(P-O)-based amorphous tribo-chemical layer of about 20 nm ***,this work may present an approach for Ils to be used as an additive in conventional lubricants due to their ability to enhance the lubrication properties,making them an alternative lubricant solution for high load-carrying gearbox applications.

关键词： ionic liquids(ILs) additives gears scuffing friction load-carrying capacity

News on the physics potential of the reaction e^+e^-→ Zγ

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Science China(Physics,Mechanics & Astronomy) 2021年第2期64卷 27-28页

作者： philipp Roloff CERN CH-1211Geneva 23Switzerland

The next large project in particle physics is widely expected to be a high-energy electron-positron *** a facility could be realised as a circular collider,like the Circular Electron Positron Collider(CEPC)and the Future e^+e^-Circular Collider(FCC-ee)[1],or as a linear collider,like the International Linear Collider(ILC)and the Compact Linear Collider(CLIC)[2].

关键词： circular positron potential

Plants against cancer:towards green Taxol production through pathway discovery and metabolic engineering

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aBIOTECH 2024年第3期5卷 394-402页

作者： philipp Zerbe Department of Plant Biology University of California DavisDavisCA 95616USA

The diversity of plant natural products presents a rich resource for accelerating drug discovery and addressing pressing human health ***,the challenges in accessing and cultivating source species,as well as metabolite structural complexity,and general low abundance present considerable hurdles in developing plant-derived *** in high-throughput sequencing,genome assembly,gene synthesis,analytical technologies,and synthetic biology approaches,now enable us to efficiently identify and engineer enzymes and metabolic pathways for producing natural and new-to-nature therapeutics and drug *** review highlights challenges and progress in plant natural product discovery and engineering by example of recent breakthroughs in identifying the missing enzymes involved in the biosynthesis of the anti-cancer agent Taxol^(®).These enzyme resources offer new avenues for the bio-manufacture and semi-synthesis of an old blockbuster drug.

关键词： Taxol Plant natural products Synthetic biology Pathway discovery Metabolic engineering

Calibration-free speckle matrix imaging

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Light(Science & Applications) 2022年第3期11卷 1-3页

作者： philipp del Hougne Univ Rennes CNRSIETR-UMR 616435000RennesFrance

Unknown speckle patterns can be used to image targets embedded in complex scattering media 100 times faster than previous techniques based on carefully calibrated illuminations.

关键词： speckle illumination faster

Effect of nanoparticle concentration on zeta-potential measurement results and reproducibility

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Particuology 2010年第3期8卷 279-285页

作者： Ratna Tantra philipp Schulze Paul Quincey National Physical Laboratory Hampton Road Teddington Middlesex TW11 0LW UK Department of Physics University of Bath Bath BA2 7AY UK. National Physical Laboratory Hampton Road Teddington Middlesex TW11 0LW

The effect of nanoparticle concentration on zeta-potential measurement results at dilute concentrations was evaluated. The values of the zeta-potential for four different types of nanoparticles, Ludox （silica）, multi-walled carbon nanotubes （bamboo-shaped and hollow nanotubes） and gold, at various concentrations, were obtained using a laser Doppler electrophoresis instrument. The size of the nanoparticles on dilution was measured using dynamic light scattering （DLS）. The results show that there is a concentration range within which the zeta-potential, and particle size, are not affected by nanoparticle concentration. The lower concentration limit for the system to produce consistent results was dependent on the nature of the sample under study and ranged between 10-2 and 10-4 wt%. Below this concentration, there was an apparent shift in zeta-potential values to less negative values, which was accompanied by an increase in the particle size. The shift in zeta-potential was attributed to an increase in contribution of the signal from extraneous particulate matter. The increase in particle size was attributed to the nature of the homodyne optical configuration of the instrument. The aim of this study was to elucidate the range in nanoparticle concentration that allows for accurate and reliable measurement of the zeta-potential and DLS data.

关键词： Nanoparticles Zeta-potential Dynamic light scattering Reproducibility

Entropy‑Conservative Discontinuous Galerkin Methods for the Shallow Water Equations with Uncertainty

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Communications on Applied Mathematics and Computation 2024年第3期6卷 1978-2010页

作者： Janina Bender philipp Öffner Institute of Mathematics University KasselMonchebergstraße 1934127 KasselGermany Institute of Mathematics Johannes Gutenberg UniversityStaudingerweg 955099 MainzGermany Mathematical Institute Technical University ClausthalErzstraße 138678 Clausthal ZellerfeldGermany

In this paper,we develop an entropy-conservative discontinuous Galerkin(DG)method for the shallow water(SW)equation with random *** of the most popular methods for uncertainty quantifcation is the generalized Polynomial Chaos(gPC)approach which we consider in the following *** apply the stochastic Galerkin(SG)method to the stochastic SW *** the SG approach in the stochastic hyperbolic SW system yields a purely deterministic system that is not necessarily hyperbolic *** lack of the hyperbolicity leads to ill-posedness and stability issues in numerical *** transforming the system using Roe variables,the hyperbolicity can be ensured and an entropy-entropy fux pair is known from a recent investigation by Gerster and Herty(***.27(3):639–671,2020).We use this pair and determine a corresponding entropy fux ***,we construct entropy conservative numerical twopoint fuxes for this augmented *** applying these new numerical fuxes in a nodal DG spectral element method(DGSEM)with fux diferencing ansatz,we obtain a provable entropy conservative(dissipative)*** numerical experiments,we validate our theoretical fndings.

关键词： Shallow water(SW)equations Entropy conservation/dissipation Uncertainty quantification Discontinuous Galerkin(DG) Generalized Polynomial Chaos(gPC)

Mode structure symmetry breaking of reversed shear Alfvén eigenmodes and its impact on the generation of parallel velocity asymmetries in energetic particle distribution

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Plasma Science and Technology 2022年第2期24卷 17-27页

作者： Guo MENG philipp LAUBER Xin WANG Zhixin LU Max-Planck-Institut fiir Plasmaphysik D-85748 GarchingGermany

In this work,the gyrokinetic eigenvalue code LIGKA,the drift-kinetic/MHD hybrid code HMGC and the gyrokinetic full-f code TRIMEG-GKX are employed to study the mode structure details of reversed shear Alfvén eigenmodes(RSAEs).Using the parameters from an ASDEXUpgrade plasma,a benchmark with the three different physical models for RSAE without and with energetic particles(EPs)is carried *** agreement has been found for the mode frequency and the growth *** structure symmetry breaking(MSSB)is observed when EPs are included,due to the EPs’non-perturbative *** is found that the MSSB properties are featured by a finite radial wave phase velocity,and the linear mode structure can be well described by an analytical complex Gaussian expressionФ(s)=e^(-σ(s-s_(0))^(2))with complex parametersσand s_(0),where s is the normalized radial *** mode structure is distorted in opposite manners when the EP drive shifted from one side of qminto the other side,and specifically,a non-zero average radial wave number with opposite signs is *** initial EP density profiles and the corresponding mode structures have been used as the input of HAGIS code to study the EP *** parallel velocity of EPs is generated in opposite directions,due to different values of the average radial wave number,corresponding to different initial EP density profiles with EP drive shifted away from the qmin.

关键词： reversed shear Alfvén eigenmode symmetry breaking energetic particles non-perturbative effects

Realising Data-Centric Scientific Workflows with Provenance-Capturing on Data Lakes

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Data Intelligence 2022年第2期4卷 426-438页

作者： Hendrik Noltet philipp Wieder Gesellschaft fur wissenschaftliche Datenverarbeitung mbH Gottingen Gottingen Gottingen 37077Germany

Since their introduction by James Dixon in 2010,data lakes get more and more attention,driven by the promise of high reusability of the stored data due to the schema-on-read *** on this idea,several additional requirements were discussed in literature to improve the general usability of the concept,like a central metadata catalog including all provenance information,an overarching data governance,or the integration with(high-performance)processing *** the necessity for a logical and a physical organisation of data lakes in order to meet those requirements is widely recognized,no concrete guidelines are yet *** most common architecture implementing this conceptual organisation is the zone architecture,where data is assigned to a certain zone depending on the degree of *** paper discusses how FAIR Digital Objects can be used in a novel approach to organize a data lake based on data types instead of zones,how they can be used to abstract the physical implementation,and how they empower generic and portable processing capabilities based on a provenance-based approach.

关键词： Data lake Provenance Workflows FAIRDigital Objects CWFR