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TACKLING INDUSTRIAL-SCALE SUPPLY CHAIN PROBLEMS BY MIXED-INTEGER PROGRAMMING

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Journal of Computational Mathematics 2019年第6期37卷 866-888页

作者： Gerald Gamrath Ambros Gleixner Thorsten Koch Matt hias Miltenberger Dimitri Kniasew Dominik Schlogel alexander Martin Dieter Weninger Zuse Institute Berlin Department Optimization SAP SE SAP Optimization friedrich-alexander-universitat erlangen-niimbetg Department Mathematics

The modeling flexibility and the optimality guarantees provided by mixed-integer programming greatly aid the design of robust and future-proof decision support *** complexity of industrial-scale supply chain optimization,however,often poses limits to the application of general mixed-integer programming *** this paper we describe algorithmic innovations that help to ensure that MIP solver performance matches the complexity of the large supply chain problems and tight time limits encountered in *** computational evaluation is based on a diverse set,modeling real-world scenarios supplied by our industry partner SAP.

关键词： Supply chain management Supply network optimization Mixed-integer linear programming Primal heuristics Numerical stability Large-scale optimization

NeuroPNM:Model reduction of pore network models using neural networks

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Particuology 2024年第3期86卷 239-251页

作者： Robert Jendersie Ali Mjalled Xiang Lu Lucas Reineking Abdolreza Kharaghani Martin Monnigmann Christian Lessig Otto-von-Guericke-universitat Magdeburg Universitatsplatz 2Magdeburg39106Germany Ruhr-universitat-Bochum Universitatstraβe 150Bochum44801Germany

Reacting particle systems play an important role in many industrial applications,for example biomass drying or the manufacturing of *** numerical modeling and simulation of such systems is therefore of great importance for an efficient,reliable,and environmentally sustainable operation of the *** complex thermodynamical,chemical,and flow processes that take place in the particles are a particular challenge in a ***,typically a large number of particles is involved,rendering an explicit treatment of individual ones impossible in a reactor-level *** approach for overcoming this challenge is to compute effective,physical parameters from single-particle,high-resolution *** can be combined with model reduction methods if the dynamical behaviour of particles must be *** network models with their unrivaled resolution have thereby been used successfully as high-resolution models,for instance to obtain the macroscopic diffusion coeffcient of *** parameter identification and model reduction have recently gained new impetus by the dramatic progress made in machine learning in the last *** report results on the use of neural networks for parameter identification and model reduction based on three-dimensional pore network models(PNM).We believe that our results provide a powerful complement to existing methodologies for reactor-level simulations with many thermally-thick particles.

关键词： Porenetwork models Neural networks Parameter estimation Reduced order model

Investigation of Influencing Parameters for Tribological Conditions in Dry Forming Processes

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1435-1441页

作者： Jennifer Steiner Marion Merklein Institute of Manufacturing Technology Friedrich-Alexander-Universitat Erlangen-Nürnberg

Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing test was selected to investigate the tribological conditions in the flange area of deep drawing processes. The influencing factors of contact pressure and varying drawing velocities were analyzed under dry and lubricated conditions. Additionally,the tool and workpiece surfaces were characterized. Besides lubrication, the contact pressure mainly determines the tribological conditions. In lubricated tests higher normal pressure reduces friction, whereas without lubrication higher pressure results in slightly increasing friction. A changing drawing velocity affects the friction when lubricant is applied. In dry experiments, no influence of velocity was found. Results of surface characterization reveal adhesion as main wear mechanism under dry conditions. Based on the investigated influence of the process parameters, an increase in process understanding for dry forming operations is derived.

关键词： Deep drawing Tribology Friction Dry forming

The Ca^(2+)-sensing receptor and the pocketome:comparing nature's complexity with human intervention in receptor modulation

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Signal Transduction and Targeted Therapy 2024年第8期9卷 3153-3154页

作者： Edda S.F.Matthees Carsten Hoffmann Institut fur Molekulare Zellbiologie CMB-Center for Molecular BiomedicineUniversitatsklinikum JenaHans-Knoll StraBe 2D-07745 JenaGermany friedrich-Schiller-universitat Jena Hans-KnollStraBe2D-07745 JenaGermany

In a recent paper published in Nature,the relatively understudied Ca^(2+)-sensing,receptor(CasR)within the Gprotein-coupled receptor(GPCR)family C,gained attention due to pioneering research led by Georgios Skiniotis ... 详细信息

关键词： Stanford gained Skin

Investigation of Laser Induced Breakdown Spectroscopy(LIBS)for the Differentiation of Nerve and Gland Tissue-A Possible Application for a Laser Surgery Feedback Control Mechanism

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Plasma Science and Technology 2016年第6期18卷 654-660页

作者： F.MEHARI M.ROHDE C.KNIPFER R.KANAWADE F.KLAMPFL W.ADLER N.OETTER F.STELZLE M.SCHMIDT Clinical Photonics Lab Erlangen Graduate School in Advanced Optical Technologies(SAOT)Friedrich-Alexander-Universitat Erlangen-NurnbergPaul-Gordan-Str.691052 ErlangenGermany Institute of Photonic Technologies Friedrich-Alexander-Universitat Erlangen-NiirnbergKonrad-Zuse-Str.3/591052 ErlangenGermany Department of Oral and Maxillofacial Surgery University Hospital ErlangenFriedrich-Alexander-Universitat Erlangen-NurnbergGliickstrasse 1191054 ErlangenGermany Chair of Biometry and Epidemiology Friedrich-Alexander-Universitat Erlangen-Niirnberg Waldstrabe 691054 ErlangenGermany

Laser surgery provides clean,fast and accurate modeling of ***,the inability to determine what kind of tissue is being ablated at the bottom of the cut may lead to the iatrogenic damage of structures that were meant to be *** this context,nerve preservation is one of the key challenges in any surgical *** example is the treatment of parotid gland pathologies,where the facial nerve（***） and its main branches run through and fan out inside the glands parenchyma.A feedback system that automatically stops the ablation to prevent nerve-tissue damage could greatly increase the applicability and safety of surgical laser *** the present study,Laser Induced Breakdown Spectroscopy（LIBS） is used to differentiate between nerve and gland tissue of an ex-vivo pig animal *** LIBS results obtained in this preliminary experiment suggest that the measured spectra,containing atomic and molecular emissions,can be used to differentiate between the two tissue *** measurements and differentiation were performed in open air and under normal stray light conditions.

关键词： laser induced breakdown spectroscopy plasma chemical composition nerveparotid gland

Light and sound- emerging imaging techniques for inflammatory bowel disease

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World Journal of Gastroenterology 2016年第25期22卷 5642-5654页

作者： Ferdinand Knieling Maximilian J Waldner Clinic for Children and Adolescent Medicine Friedrich-Alexander-Universitat Erlangen-Nurnberg91054 ErlangenGermany Medical Department 1 Friedrich-Alexander-Universitat Erlangen-Nurnberg91054 ErlangenGermany erlangen Graduate School of Advanced Optical Technologies Friedrich-Alexander-Universitat Erlangen-Nurnberg91054 ErlangenGermany

Patients with inflammatory bowel disease are known to have a high demand of recurrent evaluation for therapy and disease activity. Further, the risk of developing cancer during the disease progression is increasing from year to year. New, mostly non-radiant, quick to perform and quantitative methods are challenging, conventional endoscopy with biopsy as gold standard. Especially, new physical imaging approaches utilizing light and sound waves have facilitated the development of advanced functional and molecular modalities. Besides these advantages they hold the promise to predict personalized therapeutic responses and to spare frequent invasive procedures. Within this article we highlight their potential for initial diagnosis, assessment of disease activity and surveillance of cancer development in established techniques and recent advances such as wide-view full-spectrum endoscopy, chromoendoscopy, autofluorescence endoscopy, endocytoscopy, confocal laser endoscopy, multiphoton endoscopy, molecular imaging endoscopy, B-mode and Doppler ultrasound, contrast-enhanced ultrasound, ultrasound molecular imaging, and elastography.

关键词： Ulcerative colitis Crohn’ s disease Endoscopy Chromoendoscopy Autofluorescence endoscopy Full-view full-spectrum endoscopy Confocal endomicroscopy Multiphoton endoscopy High-definition endoscopy Ultrasound molecular imaging B-mode ultrasound Doppler ultrasound

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

Comparing two IBM implementations for the simulation of uniform packed beds

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Particuology 2024年第3期86卷 1-12页

作者： Christian Gorges Maximilian Brommer Christin Velten Siegmar Wirtz Enric Illana Mahiques Viktor Scherer Katharina Zahringer Berend van Wachem Mechanical Process Engineering Otto-von-Guericke-Universitat MagdeburgUniversitatsplatz 239106MagdeburgGermany Department of Energy Plant Technology Ruhr-Universitat BochumUniversitatsstraBe 15044780BochumGermany Laboratory of Fluid Dynamics and Technical Flows Otto-von-Guericke-Universitat MagdeburgUniversitatsplatz 239106MagdeburgGermany

Nowadays,the design of fixed packed bed reactors still relies on empirical correlations,which,especially for small tube to particle diameter ratios,are mostly too inaccurate because of the presence of wall ***,the simulation of fixed packed bed reactors plays an important role to predict and control the flow and process parameters in such,nowadays and in the *** of its straightforward applicability to non-uniform packings with particles of arbitrary shapes,the immersed boundary method(IBM)has advantages over other numerical methods and is used more and more *** paper compares two approaches of IBMs for the simulation of fixed bed reactors with spherical shaped *** classic,smooth approach is compared to the straightforward to implement blocked-off method for velocity fields above the fixed bed for particle Reynolds numbers of 300 and *** from experimental inline PIV-measurements of the reactor to be simulated serve as a basis for *** good agreement with the experiment is found for both simulation methodologies with higher resolutions,considering the more stable flow at a particle Reynolds number of *** in the different IBM approaches occurred for the more unsteady flow at a particle Reynolds number of *** to the blocked-off method,the smooth IBM reflects the formation of additional jets and recirculation zones better right above the bed,though increasing the fluid mesh resolution improves the accuracy of the blocked-off ***,a more diffusive behaviour is found for the blocked-off simulations due to the stairstep representation,which is avoided by using interpolation stencils as in the smooth *** higher mesh refinement in the blocked-off IBM this effect can be reduced,but this also increases the computational effort.

关键词： Immersed boundary method Packed bed reactor Uniform particle packing

Formulation of carbon black-ionomer dispersions for thin film formation in fuel cells

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Particuology 2019年第3期17卷 7-21页

作者： Eva Hoffmann Su Zhang Martin Thoma Cornelia Damm Wolfgang Peukert Institute of Particle Technology (LFG) Friedrich-Alexander-Universitat Erlangen-Niimberg (FAU) CauerstraJSe 4 D-91058 Erlangen Germany

The performance of proton exchange membrane fuel cells (PEMFC) is strongly determined by the structure and composition of the electrode *** interactions between the ionomer,carbon black particles,and solvent affect the suspension properties and thus the layer *** analyze the effect of the ionomer-to-carbon (I/C) weight ratio for two different types of carbon black on the suspension and layer *** branched carbon blacks with a high surface area tend to form less cracked *** less branched carbons can pack together more closely,a smaller pore size results in a larger capillary pressure during drying and thus more *** added ionomer adsorbs on the carbon particles and improves the colloidal stability of the carbon black *** carbon black aggregates are thus smaller,resulting in closer packing and thinner ***,the addition of the ionomer increases the critical coating thickness (CCT) of the layers because drying stresses are dissipated by the deformation of the ionomer,preventing crack *** optimum I/C weight ratio is identified for optimal layer formation and minimized crack formation.

关键词： Perfluorosulfonic acid (PFSA) ionomer Carbon black Layer formation Cracking Porosity