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Particle-Image Velocimetry and Force Measurements of Leading-Edge Serrations on Owl-Based Wing Models

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Journal of Bionic Engineering 2014年第3期11卷 423-438页

作者： Andrea Winzen benedikt Roidl Stephan Klan Michael Klaas Wolfgang Schroder Institute of Aerodynamics RWTH Aachen University Aachen Germany

High-resolution Particle-Image Velocimetry （PIV） and time-resolved force measurements were performed to analyze the impact of the comb-like structure on the leading edge of barn owl wings on the flow field and overall aerodynamic performance. The Reynolds number was varied in the range of 40,000 to 120,000 and the range of angle of attack was 0° to 6° for the PIV and -15° to ＋20° for the force measurements to cover the full flight envelope of the owl. As a reference, a wind-tunnel model which possessed a geometry based on the shape of a typical barn owl wing without any owl-specific adaptations was built, and measurements were performed in the aforementioned Reynolds number and angle of attack： range. This clean wing model shows a separation bubble in the distal part of the wing at higher angles of attack. Two types of comb-like structures, i.e., artificial serrations, were manufactured to model the owl＇s leading edge with respect to its length, thickness, and material properties. The artificial structures were able to reduce the size of the separation region and additionally cause a more uniform size of the vortical structures shed by the separation bubble within the Reynolds number range investigated, resulting in stable gliding flight independent of the flight velocity. However, due to increased drag coefficients in conjunction with similar lift coefficients, the overall aerodynamic performance, i.e., lift-to-drag ratio is reduced for the serrated models. Nevertheless, especially at lower Reynolds numbers the stabilizing effect of the uniform vortex size outperforms the lower aerodynamic performance.

关键词： leading-edge serrations particle-image velocimetry owl-based wing models

Optimization of the heat treatment of additively manufactured Ni-base superalloy IN718

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International Journal of Minerals,Metallurgy and Materials 2020年第5期27卷 640-648页

作者： benedikt Diepold Nora Vorlaufer Steffen Neumeier Thomas Gartner Mathias Goken Department of Materials Science&Engineering Institute IFriedrich-Alexander-Universitat Erlangen-NürnbergErlangen 91058Germany Lufthansa Technik AG Hamburg 22335Germany

Additive manufacturing(AM) of Ni-base superalloy components can lead to a significant reduction of weight in aerospace applications. AM of IN718 by selective laser melting results in a very fine dendritic microstructure with a high dislocation density due to the fast solidification process. The complex phase composition of this alloy, with three different types of precipitates and high residual stresses, necessitates adjustment of the conventional heat treatment for AM parts. To find an optimized heat treatment, the microstructures and mechanical properties of differently solution heat-treated samples were investigated by transmission and scanning electron microscopy, including electron backscatter diffraction, and compression tests. After a solution heat treatment(SHT), the Nb-rich Laves phase dissolves and the dislocation density is reduced, which eliminates the dendritic substructure. SHT at 930 or 954°C leads to the precipitation of the δ-phase, which reduces the volume fraction of the strengthening γ′-and γ′′-phases formed during the subsequent two stage aging treatment. With a higher SHT temperature of 1000°C, where no δ-phase is precipitated, higher γ′ and γ′′ volume fractions are achieved, which results in the optimum strength of all of the solution heat treated conditions.

关键词： Ni-base superalloy selective laser melting strengthening mechanism powder bed fusion microstructure

Collecting volunteered geographic information from the Global Navigation Satellite System(GNSS):experiences from the CAMALIOT project

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International Journal of Digital Earth 2023年第1期16卷 2818-2841页

作者： Linda See benedikt Soja Grzegorz Klopotek Tobias Sturn Rudi Weinacker Santosh Karanam Ivelina Georgieva Yuanxin Pan Laura Crocetti Markus Rothacher Vicente Navarro Steffen Fritz Ian McCallum Novel Data Ecosystems for Sustainability Research Group International Institute for Applied Systems Analysis(IIASA)LaxenburgAustria Institute of Geodesy and Photogrammetry ETH ZurichZurichSwitzerland Navigation Science Office European Space Agency(ESA)MadridSpain

Raw observations(carrier-phase and code observations)from the Global Navigation Satellite System(GNSS)can now be accessed from Android mobile phones(Version 7.0 onwards).This paves the way for GNSS data to be utilized for low-cost precise positioning or in ionospheric or tropospheric *** paper presents results from data collection campaigns using the CAMALIOT mobile *** the frst campaign,116.3 billion measurements from 11,828 mobile devices were collected from all *** participation decreased during the second campaign,data are still being collected *** this contribution,we demonstrate the potential of volunteered geographic information(VGl)from mobile phones to fill data gaps in geodetic station networks that collect GNSS data,*** Brazil,but also how the data can provide a denser set of observations than current networks in countries across *** also show that mobile phones capable of dual-frequency reception,which is an emerging technology that can provide a richer source of GNSS data,are contributing in a substantial ***,we present the results from a survey of participants to indicate that participation is diverse in terms of backgrounds and geography,where the dominant motivation for participation is to contribute to scientific research.

关键词： Citizen science crowdsourcing volunteered geographicinformation(VGl) global navigation satellite system(GNSS) mobile apps Earth observation

Gut-liver axis signaling in portal hypertension

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World Journal of Gastroenterology 2019年第39期25卷 5897-5917页

作者： benedikt Simbrunner Mattias Mandorfer Michael Trauner Thomas Reiberger Department of Internal Medicine Ⅲ Division of Gastroenterology and HepatologyMedical University of ViennaVienna 1180Austria Vienna Hepatic Hemodynamic Lab Medical University of ViennaVienna 1180Austria

Portal hypertension(PHT)in advanced chronic liver disease(ACLD)results from increased intrahepatic resistance caused by pathologic changes of liver tissue composition(structural component)and intrahepatic vasoconstriction(functional component).PHT is an important driver of hepatic decompensation such as development of ascites or variceal *** and an impaired intestinal barrier in ACLD facilitate translocation of bacteria and pathogen-associated molecular patterns(PAMPs)that promote disease progression via immune system activation with subsequent induction of proinflammatory and profibrogenic *** portal venous blood flow represents a critical pathophysiological mechanism linking PHT to increased intestinal permeability:The intestinal barrier function is affected by impaired microcirculation,neoangiogenesis,and abnormal vascular and mucosal *** close bidirectional relationship between the gut and the liver has been termed“gut-liver axis”.Treatment strategies targeting the gut-liver axis by modulation of microbiota composition and function,intestinal barrier integrity,as well as amelioration of liver fibrosis and PHT are supposed to exert beneficial *** activation of the farnesoid X receptor in the liver and the gut was associated with beneficial effects in animal experiments,however,further studies regarding efficacy and safety of pharmacological FXR modulation in patients with ACLD are *** this review,we summarize the clinical impact of PHT on the course of liver disease,discuss the underlying pathophysiological link of PHT to gut-liver axis signaling,and provide insight into molecular mechanisms that may represent novel therapeutic targets.

关键词： Cirrhosis Portal hypertension Gut-liver axis Bacterial translocation Intestinal barrier Farnesoid X receptor

Assessing stress conditions and impact velocities in fluidized bed opposed jet mills

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Particuology 2020年第6期18卷 12-22页

作者： Alexander Strobel benedikt Koninger Stefan Romeis Florian Schott Karl-Ernst Wirth Wolfgang Peukert Institute of Particle Technology(LFG) Friedrich-Alexander-Universitat Erlangen-NiirnbergCauerstrae 491058 ErlangenGermany

Fluidized bed opposed jet mills are capable of meeting the continuously growing dema nd for contamination-free fine *** this type of jet mill,the solid material is entrained and accelerated by expanding gas jets that are focused onto a focal point in side a fluidized *** resulting particle collisions induce *** process is affected by the relative particle velocities and the number of particle-particle ***,both quantities are ***,to date,neither relative particle velocities nor collision frequencies in such units have been *** present work introduces an innovative method to assess the stressing conditions in jet mills *** this end,mixtures of glass and ductile metal microspheres were used,with the latter employed in small ***-particle collisions between the aluminum and glass spheres lead to the formation of dents on the *** size and number of these dents are associated with the individual collision velocities and overall collision *** correlation between dent size and collision velocity was obtained from finite element calculations based on empirical *** proposed approach was validated using particle image velocimetry during secondary gas injection into a fluidized bed *** this case the effect of the distance between two opposed nozzles was *** a lab-scaled fluidized bed opposed jet mill the effects of gas pressure and hold-up were *** particle velocities were found to be sign ificantly lower tha n the gas velocities,while the nu mber of contacts per particle was determined to be extremely high.

关键词： Fluidized bed opposed jet mill Single particle probes Finite element modeling Stress number distribution Relative velocity distribution

Statistically Extrapolated Nowcasting of Summertime Precipitation over the Eastern Alps

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Advances in Atmospheric Sciences 2017年第7期34卷 925-938页

作者： Min CHEN benedikt BICA Lukas TCHLER Alexander KANN Yong WANG Institute of Urban Meteorology China Meteorological Administration Beijing 100089 China Central Institute for Meteorology and Geodynamics Vienna 1190 Austria

This paper presents a new multiple linear regression（MLR） approach to updating the hourly, extrapolated precipitation forecasts generated by the INCA（Integrated Nowcasting through Comprehensive Analysis） system for the Eastern *** generalized form of the model approximates the updated precipitation forecast as a linear response to combinations of predictors selected through a backward elimination algorithm from a pool of predictors. The predictors comprise the raw output of the extrapolated precipitation forecast, the latest radar observations, the convective analysis, and the precipitation analysis. For every MLR model, bias and distribution correction procedures are designed to further correct the systematic regression errors. Applications of the MLR models to a verification dataset containing two months of qualified samples,and to one-month gridded data, are performed and evaluated. Generally, MLR yields slight, but definite, improvements in the intensity accuracy of forecasts during the late evening to morning period, and significantly improves the forecasts for large thresholds. The structure-amplitude-location scores, used to evaluate the performance of the MLR approach,based on its simulation of morphological features, indicate that MLR typically reduces the overestimation of amplitudes and generates similar horizontal structures in precipitation patterns and slightly degraded location forecasts, when compared with the extrapolated nowcasting.

关键词： Precipitation forecast convective Eastern correction verification backward qualified degraded morning

Observation of a single protein by ultrafast X-ray diffraction

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Light(Science & Applications) 2024年第1期13卷 80-90页

作者： Tomas Ekeberg Dameli Assalauova Johan Bielecki Rebecca Boll benedikt J.Daurer Lutz A.Eichacker Linda E.Franken Davide E.Galli Luca Gelisio Lars Gumprecht Laura H.Gunn Janos Hajdu Robert Hartmann Dirk Hasse Alexandr Ignatenko Jayanath Koliyadu Olena Kulyk Ruslan Kurta Markus Kuster Wolfgang Lugmayr Jannik Lübke Adrian P.Mancuso Tommaso Mazza Carl Nettelblad Yevheniy Ovcharenko Daniel E.Rivas Max Rose Amit K.Samanta Philipp Schmidt Egor Sobolev Nicusor Timneanu Sergey Usenko Daniel Westphal Tamme Wollweber Lena Worbs Paul Lourdu Xavier Hazem Yousef Kartik Ayyer Henry N.Chapman Jonas A.Sellberg Carolin Seuring Ivan A.Vartanyants Jochen Küpper Michael Meyer Filipe R.N.C.Maia Laboratory of Molecular Biophysics Department of Cell and Molecular BiologyUppsala UniversityHusargatan 3(Box 596)SE-75124 UppsalaSweden Deutsches Electronen-Synchrotron DESY Notkestrasse 8522607 HamburgGermany European XFEL Holzkoppel 422869 SchenefeldGermany Diamond Light Source Harwell Science&Innovation CampusDidcot OX110DEUK University of Stavanger Centre Organelle ResearchRichard-Johnsensgate 44021 StavangerNorway Leibniz Institute for Experimental Virology(HPI) Centre for Structural Systems BiologyNotkestraße 8522607 HamburgGermany Dipartimento di Fisica“Aldo Pontremoli” Universitàdegli Studi di Milanovia Celoria 1620133 MilanoItaly Center for Free-Electron Laser Science DESY22607 HamburgGermany Plant Biology Section School of Integrative Plant ScienceCornell UniversityIthacaNY 14853USA PNSensor GmbH Otto-Hahn-Ring 6D-81739 MünchenGermany Biomedical and X-Ray Physics Department of Applied PhysicsAlbaNova University CenterKTH Royal Institute of TechnologySE-10691 StockholmSweden ELI Beamlines/IoP Institute of Physics AS CR v.v.i.Na Slovance 218221 Prague 8Czech Republic Multi-User CryoEM Facility Centre for Structural Systems BiologyNotkestr.8522607 HamburgGermany University Medical Center Hamburg-Eppendorf(UKE) Martinistrasse 5220246 HamburgGermany The Hamburg Center for Ultrafast Imaging Universität HamburgLuruper Chaussee 14922761 HamburgGermany Department of Physics Universität HamburgLuruper Chaussee 14922761 HamburgGermany Department of Chemistry and Physics La Trobe Institute for Molecular ScienceLa Trobe UniversityMelbourneVIC 3086Australia Division of Scientific Computing Science for Life LaboratoryDepartment of Information TechnologyUppsala UniversityBox 337SE-75105 UppsalaSweden European Molecular Biology Laboratory c/o DESYNotkestrasse 8522607 HamburgGermany Department of Physics and Astronomy Uppsala UniversityBox 516SE-75120 UppsalaSweden Max Planck Institute for the Structure and Dynamics of Matter Luruper Chaussee 14922761 HamburgGe

The idea of using ultrashort X-ray pulses to obtain images of single proteins frozen in time has fascinated and inspired *** was one of the arguments for building X-ray free-electron *** to theory,the extremely intense pulses provide sufficient signal to dispense with using crystals as an amplifier,and the ultrashort pulse duration permits capturing the diffraction data before the sample inevitably *** was first demonstrated on biological samples a decade ago on the giant *** then,a large collaboration has been pushing the limit of the smallest sample that can be *** ability to capture snapshots on the timescale of atomic vibrations,while keeping the sample at room temperature,may allow probing the entire conformational phase space of *** we show the first observation of an X-ray diffraction pattern from a single protein,that of Escherichia coli GroEL which at 14 nm in diameter is the smallest biological sample ever imaged by X-rays,and demonstrate that the concept of diffraction before destruction extends to single *** the pattern,it is possible to determine the approximate orientation of the *** experiment demonstrates the feasibility of ultrafast imaging of single proteins,opening the way to single-molecule time-resolved studies on the femtosecond timescale.

关键词： smallest intense ultrafast

First determination of the highly genotoxic fungal contaminant altertoxin II in a naturally infested apple sample

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Emerging Contaminants 2020年第1期6卷 82-86页

作者： Hannes Puntscher Doris Marko benedikt Warth Department of Food Chemistry and Toxicology Faculty of ChemistryUniversity of ViennaWahringer Str.381090ViennaAustria

Altertoxin II is an epoxide-holding perylene quinone and secondary metabolite produced by Alternaria *** genotoxic potential and the high concentrations determined in laboratory fungal cultures resulted in an increased scientific interest in this emerging ***,no natural occurrence in food has been reported to date to the best of our ***,we unambiguously identified altertoxin II in a naturally infected,unprocessed *** a validated LC-MS/MS method,fruit peel spots(approx.1 mm in diameter),typically associated with Alternaria infestation,were tested for 17 mycotoxins produced by this *** concentrations of tentoxin were determined 24 h after harvest,and the dibenzopyrones alternariol,alternariol monomethyl ether(AME)and AME-3-sulfate after six months of ***,these contamination patterns can be considered unlikely to be of toxicological concern for ***,an inconspicuous peel lesion(0.5×1 cm)separately sampled from a stored apple,exhibited considerably high concentrations of 14 Alternaria toxins,including dibenzopyrones,their barely studied modified forms(glucosides and sulfates),as well as genotoxic perylene quinones including altertoxin *** the toxicological potential of this compound,contaminations in such infected fruit parts should not be underestimated,*** the case of exposure through the consumption of fresh smoothies or fruit juices.

关键词： Alternaria alternata Emerging contaminants Genotoxicity Food safety Plant pathology Liquid chromatography tandem mass spectrometry

From herbal small RNAs to one medicine

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Science China(Life Sciences) 2019年第3期62卷 285-287页

作者： Chao Ji Skirmantas Kriaucionis benedikt M.Kessler Chengyu Jiang Institute of Basic Medical Sciences Chinese Academy of Medical SciencesDepartment of PharmacologyPeking Union Medical College Ludwig Institute for Cancer Research University of Oxford Target Discovery Institute Nuffield Department of MedicineCAMS-Oxford InstituteUniversity of Oxford State Key Laboratory of Medical Molecular Biology Institute of Basic Medical SciencesCAMS-Oxford InstituteChinese Academy of Medical SciencesDepartment of BiochemistryPeking Union Medical College

In this special topic "Herbal small RNAs, novel precision medicine from Mother Nature", we present four original articles that study the entry of small RNAs derived from herbs used in traditional Chinese medicine into mammalian cells and their function within human and mouse cells, and one review paper focusing on current trends in herb genomics (Du et al., 2017;Huang et al., 2018;Zhang et al., 2018;Li et al., 2019;Xin et al., 2018).

关键词： From herbal small RNAs one medicine