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Journal Articles

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2019

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• R Jana, L Pastewka
  Correlations of non-affine displacements in metallic glasses through the yield transition
  2019 J Phys Mater, volume: 2, page: 045006
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  Abstract

  We study correlations of non-affine displacements during simple shear deformation of Cu–Zr bulk metallic glasses in molecular dynamics calculations. In the elastic regime, our calculations show exponential correlation with a decay length that we interpret as the size of a shear transformation zone in the elastic regime. This correlation length becomes system-size dependent beyond the yield transition as our calculation develops a shear band, indicative of a diverging length scale. We discuss these observations in the context of a recent proposition of yield as a first-order phase transition.
• S Li, L Pastewka, P Gumbsch
  Glass formation by severe plastic deformation of crystalline Cu|Zr nano-layers
  2019 Acta Mater, volume: 165, pages: 577 - 586
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  Abstract

  We use molecular dynamics simulation to study the formation of glasses during severe plastic deformation of crystalline Cu|Zr nano-layers in a simple shear geometry. The early stage of plasticity is governed by dislocation plasticity. Dislocation-interface interaction induces interface roughening and slow atomic-level intermixing around interfaces. A solid-state crystal-to-amorphous transition starts near the interfaces. At high strain, the interfaces are refined to merge, leading to the formation of an intermixed glassy zone that eventually spans our simulation cell. Dislocation emission is then fully suppressed and strain is fully accommodated by this glassy phase. We characterize the crystal-to-amorphous transition using local structural measures, such as the pair distribution function and Voronoi analysis. The onset of glass formation occurs at a critical shear strain that increases with layer thickness. Our simulations indicate that the parameter controlling this onset is the theoretical affine interface distance, i.e. the amorphization occurs at a critical value of around 3-4 nm that increases slightly with the increase of layer thickness. Our work provides insights on mechanically driven glass formation in multicomponent systems, as e.g. realized in ball-mills or high-pressure torsion experiments.
• S Dalvi, A Gujrati, SR Khanal, L Pastewka, A Dhinojwala, TDB Jacobs
  Linking energy loss in soft adhesion to surface roughness
  2019 P Natl Acad Sci Usa
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  Abstract

  A mechanistic understanding of adhesion in soft materials is critical in the fields of transportation (tires, gaskets, and seals), biomaterials, microcontact printing, and soft robotics. Measurements have long demonstrated that the apparent work of adhesion coming into contact is consistently lower than the intrinsic work of adhesion for the materials, and that there is adhesion hysteresis during separation, commonly explained by viscoelastic dissipation. Still lacking is a quantitative experimentally validated link between adhesion and measured topography. Here, we used in situ measurements of contact size to investigate the adhesion behavior of soft elastic polydimethylsiloxane hemispheres (modulus ranging from 0.7 to 10 MPa) on 4 different polycrystalline diamond substrates with topography characterized across 8 orders of magnitude, including down to the angstrom scale. The results show that the reduction in apparent work of adhesion is equal to the energy required to achieve conformal contact. Further, the energy loss during contact and removal is equal to the product of the intrinsic work of adhesion and the true contact area. These findings provide a simple mechanism to quantitatively link the widely observed adhesion hysteresis to roughness rather than viscoelastic dissipation.
• A Gola, L Pastewka
  Scratching Cu|Au Nanolaminates
  2019 Lubricants, volume: 7, issue: 5, page: 44
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  Abstract

  We used molecular dynamics simulations to study the scratching of Cu|Au nanolaminates of 5 nm layer thickness with a nanoscale indenter of 15 nm radius at normal forces between 0.5μ N and 2μ N. Our simulations show that Au layers wear quickly while Cu layers are more resistant to wear. Plowing was accompanied by the roughening of the Cu|Au heterointerface that lead to the folding of the nanolaminate structure at the edge of the wear track. Our explorative simulations hint at the complex deformation processes occurring in nanolaminates under tribological load.
• R Jana, D Savio, VL Deringer, L Pastewka
  Structural and elastic properties of amorphous carbon from simulated quenching at low rates
  2019 Model Simul Mater Sc
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  Abstract

  We generate representative structural models of amorphous carbon (a-C) from constant-volume quenching from the liquid with subsequent relaxation of internal stresses in molecular dynamics simulations using empirical and machine-learning interatomic potentials. By varying volume and quench rate we generate structures with a range of density and amorphous morphologies. We find that all a-C samples show a universal relationship between hybridization, bulk modulus and density despite having distinctly different cohesive energies. Differences in cohesive energy are traced back to slight changes in the distribution of bond-angles that will likely be linked to thermal stability of these structures.
• A Gola, G-P Zhang, L Pastewka, R Schwaiger
  Surface flaws control strain localization in the deformation of Cu|Au nanolaminate pillars
  2019 Mrs Commun, volume: 9, issue: 3, pages: 1067 - 1071
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  Abstract

  The authors carried out matched experiments and molecular dynamics simulations of the compression of nanopillars prepared from Cu|Au nanolaminates with up to 25 nm layer thickness. The stress–strain behaviors obtained from both techniques are in excellent agreement. Variation in the layer thickness reveals an increase in the strength with a decreasing layer thickness. Pillars fail through the formation of shear bands whose nucleation they trace back to the existence of surface flaws. This combined approach demonstrates the crucial role of contact geometry in controlling the deformation mode and suggests that modulus-matched nanolaminates should be able to suppress strain localization while maintaining controllable strength.

2018

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• MR Chellali, SH Nandam, S Li, MH Fawey, E Moreno-Pineda, L Velasco, T Boll, L Pastewka, R Kruk, P Gumbsch, H Hahn
  Amorphous Nickel nanophases inducing ferromagnetism in equiatomic Ni-Ti alloy
  2018 Acta Mater, volume: 161, pages: 47 - 53
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  Abstract

  Ni50Ti50 nanometer-sized amorphous particles are prepared using inert-gas condensation followed by in situ compaction. Elemental segregation of Ni and Ti is observed in the consolidated nanostructured material. Amorphous, nearly pure Nickel (96%) nanophases form within the amorphous Ni50Ti50 alloy. Combining atom probe tomography and scanning transmission electron microscopy with computer modelling, we explore the formation process of such amorphous nanophase structure. It is shown that the Ni rich amorphous phase in the consolidated nanostructured material is responsible for the ferromagnetic behavior of the sample whereas the rapidly quenched amorphous and crystalline samples with the same chemical composition (Ni50Ti50) were found to be paramagnetic. Due to the high cooling rate obtained using the inert gas condensation technique, an exceptional control over the crystallization processes is possible, promoting the formation of various amorphous phases, which are not obtained by standard rapid quenching techniques. Our findings demonstrate the potential of amorphous metallic nanostructures as advanced technological materials, and useful magnetic compounds.
• A Gola, P Gumbsch, L Pastewka
  Atomic-scale simulation of structure and mechanical properties of Cu(1−x)Ag(x)|Ni multilayer systems
  2018 Acta Mater, volume: 150, pages: 236 - 247
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  Abstract

  We use a combination of atom-swap Monte-Carlo (MC) and molecular dynamics (MD) to study the structure and mechanical properties of Cu(1-x)Ag(x)|Ni multilayers with 6 nm layer width for which the Ag-content is used to tune the lattice misfit. We find that the multilayers form a semi-coherent interface with a network of partial dislocations arranged in a regular triangular pattern. A combination of MC and MD was used to equilibrate Cu(1-x)Ag(x)|Ni with x = 0%, 5% and 10%. Ag does not enter the Ni-layer but segregates and precipitates from the Cu layers. We find alloying of Cu and Ni at 600 K. All these findings are in good agreement with the experimental binary phase diagrams of the Cu-Ag, Ag-Ni and Cu-Ni systems. The resulting multilayer structures were then sheared parallel and perpendicular to the normal of the bilayer interface. Initial sliding takes place at the Cu|Ni interface within the misfit dislocation network, followed by emission of partial dislocations into the Cu layer. Flow stress increases with increasing Ag content. Additional calculations of biaxial tension that suppress sliding at the heterointerface show a similar trend. Strengthening can be attributed to Ag precipitates pinning the Cu|Ni heterointerface and to the formation of sessile stacking-fault tetrahedra from the misfit dislocation network whose density increases with the concentration of Ag in the Cu layer.
• S Khanal, A Gujrati, SB Vishnubhotla, P Nowakowski, C Bonifacio, L Pastewka, TDB Jacobs
  Characterization of small-scale surface topography using transmission electron microscopy
  2018 Surf Topogr-metrol, volume: 6, page: 045004
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  Abstract

  Multi-scale surface topography is critical to surface function, yet the very smallest scales are not accessible with conventional measurement techniques. Here we demonstrate two separate approaches for measuring small-scale topography in a transmission electron microscope (TEM). The first technique harnesses "conventional" methods for preparation of a TEM cross-section, and presents how these methods may be modified to ensure the preservation of the original surface. The second technique involves the deposition of the material of interest on a pre-fabricated substrate. Both techniques enable the observation and quantification of surface topography with Ångström-scale resolution. Then, using electron energy loss spectroscopy (EELS) to quantify the sample thickness, we demonstrate that there is no systematic effect of thickness on the statistical measurements of roughness. This result was verified using mathematical simulations of artificial surfaces with varying thickness. The proposed explanation is that increasing the side-view thickness of a randomly rough surface may change which specific features are sampled, but does not significantly alter the character (e.g., root-mean-square (RMS) values and power spectral density (PSD)) of the measured topography. Taken together, this work establishes a new approach to topography characterization, which fills in a critical gap in conventional approaches: i.e., the measurement of smallest-scale topography.
• Z Li, L Pastewka, I Szlufarska
  Chemical aging of large-scale randomly rough frictional contacts
  2018 Phys Rev E, volume: 98, page: 023001
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  Abstract

  It has been shown that contact aging due to chemical reactions in single asperity contacts can have a significant effect on friction. However, it is currently unknown how chemically induced contact aging of friction depends on roughness that is typically encountered in macroscopic rough contacts. Here we develop an approach that brings together a kinetic Monte Carlo model of chemical aging with a contact mechanics model of rough surfaces based on the boundary element method to determine the magnitude of chemical aging in silica-silica contacts with random roughness. Our multiscale model predicts that chemical aging for randomly rough contacts has a logarithmic dependence on time. It also shows that friction aging switches from a linear to a nonlinear dependence on the applied load as the load increase. We discover that surface roughness affects the aging behavior primarily by modifying the real contact area and the local contact pressure, whereas the effect of contact morphology is relatively small. Our results demonstrate how understanding of chemical aging can be translated from studies of single asperity contacts to macroscopic rough contacts.
• A Gujrati, SR Khanal, L Pastewka, TDB Jacobs
  Combining TEM, AFM, and profilometry for quantitative topography characterization across all scales
  2018 Acs Appl Mater Inter, volume: 10, issue: 34, pages: 29169 - 29178
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  Abstract

  Surface roughness affects the functional properties of surfaces, including adhesion, friction, hydrophobicity, biological response, and electrical and thermal transport properties. However, experimental investigations to quantify these links are often inconclusive, because surfaces are fractal-like and the values of measured roughness parameters depend on measurement size. Here we demonstrate the characterization of topography of an ultrananocrystalline diamond (UNCD) surface at the Ångström-scale using transmission electron microscopy (TEM), as well as its combination with conventional techniques to achieve a comprehensive surface description spanning eight orders of magnitude in size. We performed more than 100 individual measurements of the nanodiamond film using both TEM and conventional techniques (stylus profilometry and atomic force microscopy). While individual measurements of root-mean-square (RMS) height, RMS slope, and RMS curvature vary by orders of magnitude, we combine the various techniques using the power spectral density (PSD) and use this to compute scale-independent parameters. This analysis reveals that “smooth” UNCD surfaces have an RMS slope greater than one, even larger than the slope of the Austrian Alps when measured on the scale of a human step. This approach of comprehensive multi-scale roughness characterization, measured with Ångström-scale detail, will enable the systematic evaluation and optimization of other technologically relevant surfaces, as well as systematic testing of the many analytical and numerical models for the behavior of rough surfaces.
• VL Deringer, MA Caro, R Jana, A Aarva, SR Elliott, T Laurila, G Csányi, L Pastewka
  Computational surface chemistry of tetrahedral amorphous Carbon by combining machine learning and DFT
  2018 Chem Mater
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  Abstract

  Tetrahedral amorphous carbon (ta-C) is widely used for coatings due to its superior mechanical properties and has been suggested as an electrode material for detecting biomolecules. Despite extensive research, however, the complex atomic-scale structures and chemical reactivity of ta-C surfaces are incompletely understood. Here, we combine machine learning, density-functional tight-binding, and density-functional theory simulations to shed new light on this long-standing problem. We make atomistic models of ta-C surfaces, characterize them by local structural fingerprints, and provide a library of structures at different system sizes. We then move beyond the pure element and exemplify how chemical reactivity (hydrogenation and oxidation) can be modeled at the surfaces. Our work opens up new perspectives for modeling the surfaces and interfaces of amorphous solids, which will advance studies of ta-C and other functional materials.
• A Klemenz, A Gola, M Moseler, L Pastewka
  Contact mechanics of graphene-covered metal surfaces
  2018 Appl Phys Lett, volume: 112, page: 061601
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  Abstract

  We carry out molecular statics simulations of the indentation of bare and graphene-covered Pt (111) surfaces with smooth and rough indenters of radius 1.5 to 10 nm. Our simulations show that the plastic yield of bare surfaces strongly depends on atomic-scale indenter roughness such as terraces or amorphous disorder. Covering surfaces with graphene regularizes this response to the results obtained for ideally smooth indenters. Our results suggest that graphene monolayers and other 2D materials mitigate the effect of roughness, which could be exploited to improve the fidelity of experiments that probe the mechanical properties of interfaces.
• M Azhar, S Shakil, A Greiner, D Kauzlaric, JG Korvink
  DPD enables mesoscopic MRI simulation of slow flow
  2018 Microfluid Nanofluid, volume: 22, issue: 5, page: 55
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  Abstract

  We present a novel method to simulate magnetic resonance imaging (MRI) for the assessment of slow flow at Reynolds number Re≈0.02. We couple Bloch equations with dissipative particle dynamics (DPD) to study the effect of flow dynamics at the mesoscopic level on acquired MR images. The Bloch equations are used to propagate the evolution of the magnetization of particles while their trajectories are being computed simultaneously based on DPD interaction forces. The magnetic resonance assessment of fluid velocities is performed using a phase-contrast MRI technique, implemented by a spin echo single-sided bipolar gradient sequence. The computational cost for simulating the fluid flow is successfully reduced by an efficient implementation of a vectorized isochromat algorithm. We demonstrate successful simulation of laminar flow, flow with diffusion effects, and flow around an obstacle. The method can be used to simulate convective and diffusive flow MRI experiments at the mesoscopic level.
• M Azhar, S Shakil, A Greiner, D Kauzlaric, JG Korvink
  DPD of diffusion-weighted MRI
  2018 Comput Fluids, volume: 172, pages: 467 - 473
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  Abstract

  Diffusion weighted magnetic resonance imaging (DW-MRI) experiments can be simulated by coupling dissipative particle dynamics (DPD) with Bloch equations. DPD gives hydrodynamics with thermal fluctuations at a well-defined temperature by introducing momentum conserving particle interaction forces and a fluctuation dissipation theorem. The Bloch equations are a set of differential equations that describe the evolution of nuclear magnetization as a function of time. Here we successfully simulate DW-MRI by using the solution of Bloch equations for each DPD particle while computing its trajectories through DPD forces. To this end, a spin echo sequence combined with different diffusion-weighting gradients was implemented and tested for the diffusion of a fluid bound by different diffusion regimes. Fluid confinement was easily incorporated, which enabled investigating different diffusion regimes and the performance of different pulse sequences. The three different sequences applied were: spin echo single-sided bipolar gradient, spin echo two-sided bipolar gradient and spin echo uni-polar gradient; and the three imaged diffusion regimes of interest were: free diffusion, localization and motional narrowing.
• A Gola, L Pastewka
  Embedded atom method potential for studying mechanical properties of binary Cu-Au alloys
  2018 Model Simul Mater Sc, volume: 26, page: 055006
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  Abstract

  We present an embedded atom method (EAM) potential for the binary Cu–Au system. The unary phases are described by two well-tested unary EAM potentials for Cu and Au. We fitted the interaction between Cu and Au to experimental properties of the binary intermetallic phases Cu3Au, CuAu and CuAu3. Particular attention has been paid to reproducing stacking fault energies in order to obtain a potential suitable for studying deformation in this binary system. The resulting energies, lattice constant, elastic properties and melting points are in good agreement with available experimental data. We use nested sampling to show that our potential reproduces the phase boundaries between intermetallic phases and the disordered face-centered cubic solid solution. We benchmark our potential against four popular Cu–Au EAM parameterizations and density-functional theory calculations.
• B Weber, T Suhina, T Junge, L Pastewka, F Brouwer, D Bonn
  Molecular probes reveal deviations from Amontons’ law in multi-asperity frictional contacts
  2018 Nat Commun, volume: 9, page: 888
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  Abstract

  Amontons’ law defines the friction coefficient as the ratio between friction force and normal force, and assumes that both these forces depend linearly on the real contact area between the two sliding surfaces. However, experimental testing of frictional contact models has proven difficult, because few in situ experiments are able to resolve this real contact area. Here, we present a contact detection method with molecular-level sensitivity. We find that while the friction force is proportional to the real contact area, the real contact area does not increase linearly with normal force. Contact simulations show that this is due to both elastic interactions between asperities on the surface and contact plasticity of the asperities. We reproduce the contact area and fine details of the measured contact geometry by including plastic hardening into the simulations. These new insights will pave the way for a quantitative microscopic understanding of contact mechanics and tribology.
• T Kling, D Vogler, L Pastewka, F Amann, P Blum
  Numerical simulations and validation of contact mechanics in a granodiorite fracture
  2018 Rock Mech Rock Eng, volume: 51, issue: 9, pages: 2805 - 2824
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  Abstract

  Numerous rock engineering applications require a reliable estimation of fracture permeabilities to predict fluid flow and transport processes. Since measurements of fracture properties at great depth are extremely elaborate, representative fracture geometries typically are obtained from outcrops or core drillings. Thus, physically valid numerical approaches are required to compute the actual fracture geometries under in situ stress conditions. Hence, the objective of this study is the validation of a fast Fourier transform (FFT)-based numerical approach for a circular granodiorite fracture considering stress-dependent normal closure. The numerical approach employs both purely elastic and elastic–plastic contact deformation models, which are based on high-resolution fracture scans and representative mechanical properties, which were measured in laboratory experiments. The numerical approaches are validated by comparing the simulated results with uniaxial laboratory tests. The normal stresses applied in the axial direction of the cylindrical specimen vary between 0.25 and 10 MPa. The simulations indicate the best performance for the elastic–plastic model, which fits well with experimentally derived normal closure data (root-mean-squared error=9 µm). The validity of the elastic–plastic model is emphasized by a more realistic reproduction of aperture distributions, local stresses and contact areas along the fracture. Although there are differences in simulated closure for the elastic and elastic–plastic models, only slight differences in the resulting aperture distributions are observed. In contrast to alternative interpenetration models or analytical models such as the Barton–Bandis models and the “exponential repulsion model”, the numerical simulations reproduce heterogeneous local closure as well as low contact areas (<2%) even at high normal stresses (10 MPa), which coincides with findings of former experimental studies. Additionally, a relative hardness value of 0.14 for granitic rocks, which defines the general resistance to non-elastic deformation of the contacts, is introduced and successfully applied for the elastic–plastic model.
• G Moras, A Klemenz, T Reichenbach, A Gola, H Uetsuka, M Moseler, L Pastewka
  Shear melting of silicon and diamond and the disappearance of the polyamorphic transition under shear
  2018 Phys Rev Mater, volume: 2, page: 083601
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  Abstract

  Molecular dynamics simulations of diamond-cubic silicon and carbon under combined shear and compression show the formation of an amorphous solid with liquidlike structure at room temperature. Consistent with the opposite density changes of the two crystals upon melting, the amorphous material is denser than the crystal in silicon and less dense than the crystal in carbon. As a result, its rate of formation is enhanced by pressure in silicon but suppressed in carbon. These results are particularly unexpected for silicon, whose amorphous structure is supposed to be liquidlike only when hydrostatically compressed above the polyamorphic transition pressure (∼14 GPa). Below this pressure, amorphous silicon is expected to have a low-density structure with density close to that of the diamond-cubic crystal. Our simulations show that this polyamorphic transition disappears under shear and high-density, liquidlike amorphous silicon with metallic ductility forms even at low pressure. These results are potentially transferable to other diamond-cubic crystals, like germanium and ice Ih, and provide insights into nonequilibrium materials transformations that govern friction and wear in tribological systems.
• C Greiner, Z Liu, R Schneider, L Pastewka, P Gumbsch
  The origin of surface microstructure evolution in sliding friction
  2018 Scripta Mater, volume: 153, pages: 63 - 67
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  Abstract

  A typical tribologically induced microstructure displays a discontinuity parallel to the surface separating the near-surface layer from the bulk. Despite its ubiquitous observation, the origin of this layer underneath the surface remains elusive. Here, we show that already after the first loading pass a localized dislocation structure is found at a depth of 100–150 nm. This structure is linked to the inhomogeneous stress field under the moving indenter, where dislocations are trapped when the stress drops below the material's yield stress. Control of the initial tribological loading could therefore be exploited to design surfaces and materials with superior tribological properties.

2017

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• MH Müser, WB Dapp, R Bugnicourt, P Sainsot, N Lesaffre, TA Lubrecht, BNJ Persson, K Harris, A Bennett, K Schulze, S Rohde, P Ifju, WG Sawyer, T Angelini, EH Ashtari, M Kadkhodaei, S Akbarzadeh, J-J Wu, G Vorlaufer, A Vernes, S Solhjoo, AI Vakis, RL Jackson, Y Xu, J Streator, A Rostami, D Dini, S Medina, G Carbone, F Bottiglione, L Afferrante, J Monti, L Pastewka, MO Robbins, JA Greenwood
  Meeting the Contact-Mechanics Challenge
  2017 Tribology Letters, volume: 65, issue: 4, page: 118
• TDB Jacobs, T Junge, L Pastewka
  Quantitative characterization of surface topography using spectral analysis
  2017 Surf. Topogr. Metrol. Prop., volume: 5, page: 013001
• TA Sharp, L Pastewka, VL Lignères, MO Robbins
  Scale- and load-dependent friction in commensurate sphere-on-flat contacts
  2017 Phys Rev B, volume: 96, page: 155436
• A Larsen, J Mortensen, J Blomqvist, I Castelli, R Christensen, M Dulak, J Friis, M Groves, B Hammer, C Hargus, E Hermes, P Jennings, P Jensen, J Kermode, J Kitchin, E Kolsbjerg, J Kubal, K Kaasbjerg, S Lysgaard, J Maronsson, T Maxson, T Olsen, L Pastewka, A Peterson, C Rostgaard, J Schiøtz, O Schütt, M Strange, K Thygesen, T Vegge, L Vilhelmsen, M Walter, Z Zeng, KW Jacobsen
  The Atomic Simulation Environment — A Python library for working with atoms
  2017 J Phys-condens Mat, volume: 29, page: 273002

2016

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• A Peguiron, G Moras, M Walter, H Uetsuka, L Pastewka, M Moseler
  Activation and mechanochemical breaking of C−C bonds initiate wear of diamond (110) surfaces in contact with silica
  2016 Carbon, volume: 98, pages: 474 - 483
• D Savio, L Pastewka, P Gumbsch
  Boundary lubrication of heterogeneous surfaces and the onset of cavitation in frictional contacts
  2016 Science Advances, volume: 2 , page: e1501585
• L Pastewka, MO Robbins
  Contact area of rough spheres: Large scale simulations and simple scaling laws
  2016 Appl Phys Lett, volume: 108, page: 221601
• M Azhar, A Greiner, JG Korvink, D Kauzlaric
  Dissipative particle dynamics of diffusion-NMR requires high Schmidt-numbers
  2016 J Chem Phys, volume: 144, page: 244101
• TA Sharp, L Pastewka, MO Robbins
  Elasticity limits structural superlubricity in large contacts
  2016 Phys Rev B, volume: 93, page: 121402
• J von Lautz, L Pastewka, P Gumbsch, M Moseler
  Molecular dynamic simulation of collision-induced third-body formation in hydrogen-free diamond-like Carbon asperities
  2016 Tribol Lett, volume: 63, page: 26
• M Walter, M Moseler, L Pastewka
  Offset-corrected Δ-Kohn-Sham scheme for the semi-empirical prediction of X-ray photoelectron spectra of molecules and solids
  2016 Phys Rev B, volume: 94, page: 041112

2015

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• MI De Barros Bouchet, C Matta, B Vacher, Th Le-Mogne, JM Martin, J von Lautz, T Ma, L Pastewka, J Otschik, P Gumbsch, M Moseler
  Energy filtering transmission electron microscopy and atomistic simulations of tribo-induced hybridization change of nanocrystalline diamond coating
  2015 Carbon, volume: 87, page: 317
• JR Kermode, A Gleizer, G Kovel, L Pastewka, G Csányi, D Sherman, A de Vita
  Low speed crack propagation via kink formation and advance on the silicon (110) cleavage plane
  2015 Phys Rev Lett, volume: 115, page: 135501

2014

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• A Klemenz, L Pastewka, SG Balakrishna, A Caron, R Bennewitz, M Moseler
  Atomic scale mechanisms of friction reduction and wear protection by graphene
  2014 Nano Lett, volume: 14, page: 7145
• L Pastewka, MO Robbins
  Contact between rough surfaces and a criterion for macroscopic adhesion
  2014 PNAS, volume: 111, page: 3298
• N. Moradi, A. Greiner, S. Melchionna, R. Rao, S. Succi
  Hydro-kinetic scheme for the dynamics of hydrogen bonds in water-like fluids
  2014 Phys Chem Chem Phys, volume: 16, pages: 15510 - 15518
• D Kauzlaric, M Dynowski, L Pastewka, A Greiner, JG Korvink
  SYMPLER: SYMbolic ParticLE simulatoR with grid-computing interface,
  2014 Comput Phys Commun, volume: 185, issue: 3, pages: 1085 - 1099
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  Abstract

  We present the main design concepts of the object-oriented particle dynamics code SYMPLER. With this freely available software, simulations can be performed ranging from microscopic classical molecular dynamics up to the Lagrangian particle-based discretisation of macroscopic continuum mechanics equations. We show how the runtime definition of arbitrary degrees of freedom and of arbitrary equations of motion allows for modular and symbolic computation with high flexibility. Arbitrary symbolic expressions for inter-particle forces can be defined as well as fluxes of arbitrarily many additional scalar, vectorial or tensorial degrees of freedom. The integration in a high performance grid computing environment makes huge geographically distributed computational ressources accessible to the software by an easy-to-use interface.
• PA Romero, L Pastewka, J von Lautz, M Moseler
  Surface passivation and boundary lubrication of self-mated tetrahedral amorphous carbon asperities under extreme tribological conditions
  2014 Friction, volume: 2, page: 193
• T Kunze, M Posselt, S Gemming, G Seifert, AR. Konicek, RW Carpick, L Pastewka, M Moseler
  Wear, plasticity, and rehybridization in tetrahedral amorphous carbon
  2014 Tribol Lett, volume: 53, page: 119

2013

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• TT Järvi, L Mayrhofer, J Polvi, K Nordlund, L Pastewka, M Moseler
  Adaptive molecular decomposition: Large scale quantum chemistry for liquids
  2013 J Chem Phys, volume: 138, page: 104108
• IA Lyashenko, L Pastewka, BNJ Persson
  Comment on “Friction between a viscoelastic body and a rigid surface with random self-affine roughness”
  2013 Phys Rev Lett, volume: 111, page: 189401
• P Stoyanov, PA Romero, TT Järvi, L Pastewka, M Scherge, P Stemmer, A Fischer, M Dienwiebel, M Moseler
  Experimental and numerical atomistic investigation of the third body formation process in dry tungsten/tungsten-carbide tribo couples
  2013 Tribol Lett, volume: 50, page: 67
• L Pastewka, N Prodanov, B Lorenz, MH Müser, MO Robbins, BNJ Persson
  Finite-size scaling in the interfacial stiffness of rough elastic contacts
  2013 Phys Rev B, volume: 87, page: 062809
• N Moradi, A Greiner, F Rao, S Succi
  Lattice Boltzmann implementation of the three-dimensional Ben-Naim potential for water-like fluids,
  2013 J Chem Phys, volume: 138, page: 124105
• L Pastewka, S Malola, M Moseler, P Koskinen
  Li+ adsorption at prismatic graphite surfaces enhances interlayer cohesion
  2013 J Power Sources, volume: 239, page: 321
• T Kaib, P Bron, S Haddadpour, L Mayrhofer, L Pastewka, TT Järvi, M Moseler, B Roling, S Dehnen
  Lithium chalcogenidotetrelates: LiChT – Synthesis and characterization of new Li+ ion conducting Li/Sn/Se compounds
  2013 Chem Mater, volume: 25, page: 2961
• D Kauzlaric, J T Meier, P Espanol, A Greiner, S Succi
  Markovian equations of motion for non-Markovian coarse-graining and properties for graphene blobs
  2013 New J Phys, volume: 15, page: 125015
• A Fuchs, D Kauzlaric, A Greiner, S Succi, JG Korvink
  Molecular Dynamics Simulations of Nanoparticle Interactions with a Planar Wall: Does Shape Matter?,
  2013 Commun Comput Phys, volume: 13, issue: 3, pages: 900 - 915
• IA Lyashenko, L Pastewka, BNJ Persson
  On the validity of the method of reduction of dimensionality: area of contact, average interfacial separation and contact stiffness
  2013 Tribol Lett, volume: 52, page: 223
• D Weiss, A Greiner, J Lienemann, JG Korvink
  SPH based optimization of electrowetting driven digital microfluidics with advanced actuation patterns,
  2013 Int J Mod Phys C, volume: 24, issue: 12, page: 1340012
• L Pastewka, A Klemenz, P Gumbsch, M Moseler
  Screened empirical bond-order potentials for Si-C
  2013 Phys Rev E, volume: 87, page: 205410

2012

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• L Pastewka, M Mrovec, M Moseler, P Gumbsch
  Bond-order potentials for fracture, wear, and plasticity
  2012 Mrs Bull, volume: 37, pages: 493 - 503
• J Lienemann, D Weiß, A Greiner, D Kauzlaric, O Gruenert, JG Korvink
  Insight into the micro scale dynamics of a micro fluidic wetting-based conveying system by particle based simulation,
  2012 Microsyst Technol, volume: 18, issue: 4, pages: 523 - 530
  » show abstract« hide abstract
  Abstract

  We simulate a microfluidic conveying system using the many-body dissipative particle dynamics method (MDPD). The conveying system can transport micro parts to a specified spot on a surface by letting them float inside or on top of a droplet, which is pumped by changing the wetting behaviour of the substrate, e.g., with electrowetting on dielectrics. Subsequent evaporation removes the fluid; the micro part remains on its final position, where a second substrate can pick it up. In this way, the wetting control can be separate from the final device substrate. The MDPD method represents a fluid by particles, which are interpreted as a coarse graining of the fluid’s molecules. The choice of interaction forces allows for free surfaces. To introduce a contact angle model, non-moving particles beyond the substrate interact with the fluid particles by MDPD forces such that the required contact angle emerges. The micro part is simulated by particles with spring-type interaction forces.
• D Kauzlaric, P Espanol, A Greiner, S Succi
  Markovian dissipative coarse grained molecular dynamics for a simple 2D graphene model,
  2012 J Chem Phys, volume: 137, issue: 23, page: 234103
  » show abstract« hide abstract
  Abstract

  Based upon a finite-element “coarse-grained molecular dynamics” (CGMD) procedure, as applied to a simple atomistic 2D model of graphene, we formulate a new coarse-grained model for graphene mechanics explicitly accounting for dissipative effects. It is shown that, within the Mori-projection operator formalism, the reversible part of the dynamics is equivalent to the finite temperature CGMD-equations of motion, and that dissipative contributions to CGMD can also be included within the Mori formalism. The CGMD nodal momenta in the present graphene model display clear non-Markovian behavior, a property that can be ascribed to the fact that the CGMD-weighting function suppresses high-frequency modes more effectively than, e.g., a simple center of mass (COM) based CG procedure. The present coarse-grained graphene model is also shown to reproduce the short time behavior of the momentum correlation functions more accurately than COM-variables and it is less dissipative than COM-CG. Finally, we find that, while the intermediate time scale represented directly by the CGMD variables shows a clear non-Markovian dynamics, the macroscopic dynamics of normal modes can be approximated by a Markovian dissipation, with friction coefficients scaling like the square of the wave vector. This opens the way to the development of a CGMD model capable of describing the correct long time behavior of such macroscopic normal modes.
• L Pastewka, TA Sharp, MO Robbins
  Seamless elastic boundaries for atomistic calculations
  2012 Phys Rev B, volume: 86, page: 075459

2011

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• D Kauzlaric, A Greiner, JG Korvink
  A non-local extension of the Phillips model for shear induced particle migration,
  2011 Microsyst Technol, volume: 17, issue: 2, pages: 265 - 272
• L Pastewka, S Moser, P Gumbsch, M Moseler
  Anisotropic mechanical amorphization drives wear in diamond
  2011 Nat Mater, volume: 10, page: 34
• D Kauzlarić, JT Meier, P Español, S Succi, A Greiner, JG Korvink
  Bottom-up coarse-graining of a simple graphene model: The blob picture,
  2011 J Chem Phys, volume: 134, issue: 6, page: 064106
  » show abstract« hide abstract
  Abstract

  The coarse-graining of a simple all-atom 2D microscopic model of graphene, in terms of “blobs” described by center of mass variables, is presented. The equations of motion of the coarse-grained variables take the form of dissipative particle dynamics (DPD). The coarse-grained conservative forces and the friction of the DPD model are obtained via a bottom-up procedure from molecular dynamics (MD) simulations. The separation of timescales for blobs of 24 and 96 carbon atoms is sufficiently pronounced for the Markovian assumption, inherent to the DPD model, to provide satisfactory results. In particular, the MD velocity autocorrelation function of the blobs is well reproduced by the DPD model, provided that the effect of friction and noise is taken into account. However, DPD cross-correlations between neighbor blobs show appreciable discrepancies with respect to the MD results. Possible extensions to mend these discrepancies are briefly outlined.
• L Pastewka, TT Järvi, L Mayrhofer, M Moseler
  Charge-transfer model for carbonaceous electrodes in polar environments
  2011 Phys Rev B, volume: 83, page: 165418
• I Cenova, D Kauzlaric, A Greiner, JG Korvink
  Constrained simulations of flow in haemodynamic devices: towards a computational assistance of magnetic resonance imaging measurements,
  2011 Philos T R Soc A, volume: 369, issue: 1945, pages: 2494 - 2501
  » show abstract« hide abstract
  Abstract

  Cardiovascular diseases, mostly related to atherosclerosis, are the major cause of death in industrial countries. It is observed that blood flow dynamics play an important role in the aetiology of atherosclerosis. Especially, the blood velocity distribution is an important indicator for predisposition regions. Today magnetic resonance imaging (MRI) delivers, in addition to the morphology of the cardiovascular system, blood flow patterns. However, the spatial resolution of the data is slightly less than 1 mm and owing to severe restrictions in magnetic field gradient switching frequencies and intensities, this limit will be very hard to overcome. In this paper, constrained fluid dynamics is applied within the smoothed particle hydrodynamics formalism to enhance the MRI flow data. On the one hand, constraints based on the known volumetric flow rate are applied. They prove the plausibility of the order of magnitude of the measurements. On the other hand, the higher resolution of the simulation allows one to determine in detail the flow field between the coarse data points and thus to improve their spatial resolution.
• E Bouendeu, A Greiner, P Smith, JG Korvink
  Design Synthesis of Electromagnetic Vibration-Driven Energy Generators Using a Variational Formulation,
  2011 J Microelectromech S, volume: 20, issue: 1, pages: 460 - 469
  » show abstract« hide abstract
  Abstract

  This paper reports upon the design of electromagnetic vibration-driven energy generators using a variational formulation to derive the equation of motion of such generators, thereby gaining insight into the device physics. Using this approach, the characteristics of the generator are analytically studied, a newly developed optimization theory of the generator is derived, and a guide for the sizing process is described. A fabricated prototype of an electromagnetic vibration harvester is presented. For the fabrication of the prototype, printed circuit board materials and PMMA have been used to lower the cost and to achieve lightweight device. Analytical and experimental results are presented and compared. The fabricated harvester weighs 7 g, delivers 315 mu W at optimum excitation parameters at room temperature, and has a mechanical damping ratio of 0.0186. Experimental and analytical results show good agreement with the newly developed optimization theory. An analytical expression of the optimum load resistance is also developed and validated with experimental results, which show the frequency dependence of the optimum load resistance. It is also demonstrated that the optimization process needs two iterations if the mechanical damping ratio is unknown at the start of development and that the coil parameters represent the degree of freedom of the designer.
• E Bertarelli, A Corigliano, A Greiner, JG Korvink
  Design of high stroke electrostatic micropumps: a charge control approach with ring electrodes,
  2011 Microsyst Technol, volume: 17, pages: 165 - 173
  » show abstract« hide abstract
  Abstract

  A novel design strategy to avoid pull-in occurrence in electrostatic micro electro mechanical sys- tems is proposed. It combines charge control with ring electrodes, on a circular geometry. This idea is introduced here for the design of efficient and reliable high stroke electrostatic diaphragm micropumps, while it has a broad potential applicability. A minimal lumped one degree-of- freedom model is derived and used to introduce and demonstrate the proposed approach for a circular plate geometry. Finite element models are subsequently adopted for a more detailed device modelling. As expected, charge control exhibits a stabilizing effect with respect to voltage drive, but not sufficient to achieve a full-range stability for the considered geometry. When the electrode area is properly defined, stability range can be extended up to gap closure in the central part of the membrane. In this con- figuration, the increase in voltage required for full-range device drive would be relevant, while in charge control the penalty is considerably lower. Finally, loading conditions and geometrical parameters for an optimized actuation are suggested.
• G Moras, L Pastewka, P Gumbsch, M Moseler
  Formation and oxidation of linear carbon chains and their role in the wear of carbon materials
  2011 Tribol Lett, volume: 44, page: 355
• U Baur, P Benner, A Greiner, JG Korvink, J Lienemann, C Moosmann
  Parameter preserving model order reduction for MEMS applications,
  2011 Mathematical and Computer Modelling of Dynamical Systems, volume: 17, issue: 4, pages: 297 - 317
  » show abstract« hide abstract
  Abstract

  Model order reduction techniques are known to work reliably for finite element-type simulations of micro-electro-mechanical systems devices. These techniques can tremendously shorten computational times for transient and harmonic analyses. However, standard model reduction techniques cannot be applied if the equation sys- tem incorporates time-varying matrices or parameters that are to be preserved for the reduced model. However, design cycles often involve parameter modification, which should remain possible also in the reduced model. In this article we demonstrate a novel parameterization method to numerically construct highly accurate parametric ordinary differential equation systems based on a small number of systems with different param- eter settings. This method is demonstrated to parameterize the geometry of a model of a micro-gyroscope, where the relative error introduced by the parameterization lies in the region of 10−9. We also present recent developments on semi-automatic order reduction methods that can preserve scalar parameters or functions during the reduction process. The first approach is based on a multivariate Padé-type expansion. The second approach is a coupling of the balanced truncation method for model order reduction of (determin- istic) linear, time-invariant systems with interpolation. The approach is quite flexible in allowing the use of numerous interpolation techniques like polynomial, Hermite, rational, sinc and spline interpolation. As technical examples we investigate a micro anemometer as well as the gyroscope. Speed-up factors of 20–80 could be achieved, while retaining up to six parameters and keeping typical relative errors below 1%.
• G Moras, L Pastewka, M Walter, J Schnagl, P Gumbsch, M Moseler
  Progressive shortening of sp-hybridized carbon chains through oxygen-induced cleavage
  2011 J Phys Chem C, volume: 115, page: 24653
• OO Kit, L Pastewka, P Koskinen
  Revised periodic boundary conditions: Fundamentals, electrostatics, and the tight-binding approximation
  2011 Phys Rev B, volume: 84, page: 155431
• A Greiner, D Kauzlaric, JG Korvink, R Heldele, M Schulz, V Piotter, T Hanemann, O Weber, J Haußelt
  Simulation of micro powder injection moulding: powder segregation and yield stress effects during form filling,
  2011 J Eur Ceram Soc, volume: 31, issue: 14, pages: 2525 - 2534
• D Weiß, J Lienemann, A Greiner, D Kauzlarić, JG Korvink
  Smoothed particle dynamics based numerical investigation on sessile, oscillating droplets,
  2011 Philos T R Soc A, volume: 369, issue: 1945, pages: 2565 - 2573
• D Kauzlaric, L Pastewka, H Meyer, R Heldele, M Schulz, O. Weber, V Piotter, J Hausselt, A Greiner, JG Korvink
  Smoothed particle hydrodynamics simulation of shear-induced powder migration in injection moulding,
  2011 Philos T R Soc A, volume: 369, pages: 2320 - 2328
• D Kauzlaric, P Espanol, A Greiner, S Succi
  Three Routes to the Friction Matrix and Their Application to the Coarse-Graining of Atomic Lattices,
  2011 Macromol Theor Simul, volume: 20, issue: 7, pages: 526 - 540
  » show abstract« hide abstract
  Abstract

  The calculation of the friction matrix in the coarse-grained (CG) description of an atomistic system is a crucial issue, in order to properly account for the dissipative effects inherent to any reduced representation of the atomistic dynamics. Within the Mori-Zwanzig projection operator approach to CG, there are several possibilities for the definition of the friction matrix, depending on the projector that is being used. In this paper, the connection of two of these projectors (Mori's and Zwanzig's) is discussed and the corresponding merits and limitations are analysed. Moreover, three different ways of computing the friction matrix in the Mori's framework are presented, along with a discussion of their mutual connections. By the example of CG centre of mass blob variables in the graphene lattice, it is shown that, even though the three approaches are equivalent from a theoretical viewpoint, they may differ considerably in terms of practical implementation for computer simulation purposes. In the given example, which is representative for atomic lattices, it turns out that a linear regression of the velocity–velocity correlation function, inspired by the Einstein–Helfand approach, is the least error-prone against disturbances from optical modes.

2010

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• E Bouendeu, A Greiner, PJ Smith, JG Korvink
  A low cost electromagnetic Generator for vibration energy harvesting,
  2010 Ieee Sens J, volume: 11, issue: 1, pages: 107 - 113
  » show abstract« hide abstract
  Abstract

  This paper reports on a low-cost, high- performance generator, which is based on a hybrid approach that uses polymethyl methalcrylate and electrodeposited foil to convert mechanical vibration into electrical power based on Faraday’’s law of magnetic induction. The generator is equipped with four wire-wound micro-coils that can be used separately or connected together depending on the voltage and electrical power requirement of the application. The fabricated generator which has a harvester effectiveness of 55.5 % was able to supply a 500 ␣-load with 422 μW of electrical power. Investigations have revealed that the utilisation factor of the mechanical resonator can be used as an indicator of the lifetime of the generator with respect to fatigue analysis. The reported generator weighs only 12.7 g and is a good candidate for applications where lightweight generators are important.
• L Pastewka, S Moser, M. Moseler
  Atomistic insights into the running-in, lubrication, and failure of hydrogenated diamond-like carbon coatings
  2010 Tribol Lett, volume: 39, page: 49
• L Pastewka, J Peguiron, P Gumbsch, M Moseler
  Molecular dynamics simulation of gold solid film lubrication
  2010 Int J Mater Res, volume: 101, page: 981

2009

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• M Geier, A Greiner, JG Korvink
  A factorized central moment lattice Boltzmann method,
  2009 Eur Phys J-spec Top, volume: 171, pages: 55 - 61
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  Abstract

  We determine appropriate attractors for higher than third-order central moments for the relaxation process in three-dimensional lattice Boltzmann methods. It was previously assumed that the appropriate attractors for the relaxation of these moments were their equilibria values as derived from a Maxwell-Boltzmann distribution. However, when the attractor for fourth-order central moments is derived that way, the solution of three-dimensional lattice Boltzmann differs significantly from the analytical solution of the Navier-Stokes equation for simple test cases like Poiseuille flow. We show that the Navier-Stokes solution is recovered when we chose products of low order central moments as the attractors of the higher order central moments.
• M Geier, A Greiner, JG Korvink
  Bubble functions for the lattice Boltzmann method and their application to grid refinement,
  2009 Eur Phys J-spec Top, volume: 171, pages: 173 - 179
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  Abstract

  We present a new methodology of velocity field interpolation for the lattice Boltzmann method. The local information on spatial velocity gradients stored in the nodal momentum distribution function is exploited. We achieve quadratic interpolation order between neighboring nodes. Second-order bubble functions are derived from which the off-grid velocity field can be computed. A simple grid-refinement technique based on the bubble functions is introduced.
• L Pastewka, R Salzer, A Graff, F Altmann, M Moseler
  Surface amorphization, sputter rate, and intrinsic stresses of silicon during low energy Ga+ focused-ion beam milling
  2009 Nucl Instrum Meth B, volume: 267, page: 3072
• L Pastewka, P Koskinen, C Elsässer, M Moseler
  Understanding the microscopic processes that govern the charge-induced deformation of carbon nanotubes
  2009 Phys Rev B, volume: 80, page: 155428

2008

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• O Liba, D Kauzlaric, ZR Abrams, Y Hanein, A Greiner, JG Korvink
  A dissipative particle dynamics model of carbon nanotubes,
  2008 Mol Simulat, volume: 34, issue: 8, pages: 737 - 748
  » show abstract« hide abstract
  Abstract

  A mesoscale dissipative particle dynamics model of single wall carbon nanotubes (CNTs) is designed and demonstrated. The coarse-grained model is produced by grouping together carbon atoms and by bonding the new lumped particles through pair and triplet forces. The mechanical properties of the simulated tube are determined by the bonding forces, which are derived by virtual experiments. Through the introduction of van der Waals interactions, tube-tube interactions were studied. Owing to the reduced number of particles, this model allows the simulation of relatively large systems. The applicability of the presented scheme to model CNT based mechanical devices is discussed.
• L Pastewka, P Pou, R Pérez, P Gumbsch, M Moseler
  Describing bond-breaking processes by reactive potentials: the importance of an environment-dependent interaction range
  2008 Phys Rev B, volume: 78, page: 161402(R)
• D Kauzlaric, J Lienemann, L Pastewka, A Greiner, JG Korvink
  Integrated process simulation of primary shaping: multi scale approaches,
  2008 Microsyst Technol, volume: 14, issue: 12, pages: 1789 - 1796
  » show abstract« hide abstract
  Abstract

  We investigate simulation approaches for the modelling of the primary shaping processes micro powder injection moulding and micro casting. We could reproduce the segregation during micro powder injection moulding (MicroPIM) with a simulation using particle methods. The phase field method allows for accurate prediction of the dynamics of solidification of a melt, whereby model order reduction is used to limit the computational effort. The results give valuable advice for the process conduct and the dimensioning of the micro parts.
• O Liba, Y Hanein, D Kauzlaric, A Greiner, JG Korvink
  Investigation of the Dynamic Behavior of Bridged Nanotube Resonators by Dissipative Particle Dynamics Simulation,
  2008 Int J Multiscale Com, volume: 6, issue: 6, pages: 549 - 562
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  Abstract

  Carbon nanotube (CNT)-based bridged resonators are investigated using a mesoscale dissipative particle dynamics model. Owing to their nanometer size, low mass, and ultrahigh resonance frequency, CNT-based resonators have the potential to become excellent tension, strain, or mass sensors. In this report, the resonance frequency of tubes of different lengths and in different states of tension is extracted from the numerical results and shown to fit with continuum elastic theory. Since in many cases, CNTs are produced slacked rather than taut, the effect of slackness on the resonance frequencies is presented and shown to reduce the sensitivity of the resonator considerably. According to our simulations, temperature has a major effect on the resonance frequencies and should be considered when analyzing bridged resonators. The investigation includes measurements of the vibration amplitude at different temperature, tube length, and strain. The intrinsic quality factor of carbon nanotube resonators is also discussed. Finally, the simulations presented here show that the dissipative particle dynamics model is suited to describe CNT devices such as resonator-based sensors.
• L Del Tin, A Greiner, JG Korvink
  Model Order Reduction for Circuit Level Simulation of RF MEMS Frequency Selective Devices,
  2008 Sensor Lett, volume: 6, issue: 1, pages: 1 - 8
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  Abstract

  The development of complex radio frequency circuits with integrated micromechanical devices requires the availability of tools for predictive design, optimization and verification of the complete system. In this paper, a methodology towards this goal is proposed. It enables the extraction of non-linear low order models of vibrating micromechanical devices suitable for use in a standard circuit level simulator. The reduction of the complexity of the model is achieved by using moment matching model order reduction, together with an approximated lumped description of the electrostatic forces. In this way, both high simulation accuracy and low computational complexity are obtained.
• L Pastewka, S Moser, M Moseler, B Blug, S Meier, T. Hollstein, P. Gumbsch
  The running-in of amorphous hydrocarbon tribocoatings: a comparison between experiment and molecular dynamics simulations
  2008 Int J Mater Res, volume: 99, page: 1136

2007

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• M Geier, A Greiner, JG Korvink
  Properties of the cascaded lattice Boltzmann automaton,
  2007 International Journal of Modern Physics C, volume: 18, issue: 4, pages: 455 - 462
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  Abstract

  The theory of the lattice Boltzmann automaton is based on a moment transform which is not Galilean invariant. It is explained how the central moments transform, used in the cascaded latticeBoltzmann method, overcomes this problem by choosing the center of mass coordinate system as the frame of reference. Galilean invariance is restored and the form of the kinetic theory is unaffected. Conservation laws are not compromised by the high order polyinomials in the equilibrium distribution arising from the central moment transform. Two sources of instabilities in lattice Boltzmann simulations are discussed: negative numerical viscosity due to insufficient Galilean invariance and aliasing. The cascaded lattice Boltzmann automaton overcomes both problems. It is discussed why aliasing is unavoidable in lattice Boltzmann methods that rely on a single relaxation time. An appendix lists the complete scattering operator of the D2Q9 cascaded lattice Boltzmann automaton.

2006

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• M Geier, A Greiner, JG Korvink
  Cascaded Digital Lattice Boltzmann Automata for High Reynolds Number Flow,
  2006 Phys Rev E, volume: 73, page: 066705
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  Abstract

  Lattice Boltzmann methods are of limited applicability for direct numerical simulation of turbulent flow due to instabilities in the zero viscosity limit. We observe that this is caused by an insufficient degree of Galilean invariance of the relaxation-type Lattice Boltzmann collision operator. The cascaded digital lattice Boltzmann automata described here, provides a method with which to achieve stable collision operators down to the limit of zero viscosity.
• J Lienemann, EB Rudnyi, JG Korvink
  MST MEMS model order reduction: Requirements and benchmarks,
  2006 Linear Algebra Appl, volume: 415, issue: 2-3, pages: 469 - 498
  » show abstract« hide abstract
  Abstract

  The needs for model reduction in microsystem technology (MST) are described from an engineering perspective. Two representative MST model reduction benchmarks are presented in order to facilitate further development in this area. The first benchmark application is from the area of electro-thermal simulation, the second one considers an electrostatically actuated beam as found in radio frequency applications. Model reduction is contrasted with compact modeling, which currently enjoys widespread use among engineers, and important challenges to be addressed are listed.
• R Heldele, M Schulz, D Kauzlaric, JG Korvink, J Hausselt
  Micro powder injection molding: process characterization and modeling,
  2006 Microsyst Technol, volume: 12, issue: 10, pages: 941 - 946
  » show abstract« hide abstract
  Abstract

  The development of a new simulation tool for micro powder injection molding (MicroPIM) needs experimental material data and verification experiments to describe the process correctly. A new and innovative approach is to use dissipative particle dynamics (DPD) to describe the form filling process with respect to the interactions on a mesoscopic scale (Hoogerbrugge and Koelman in Europhys Lett 19(1):155–160, 1992). The individual parameters that enter DPD modeling of this process have to be adjusted using specially designed experiments for the injection molding process. The material properties in the standard injection molding process are primarily determined by the bulk material. In micro dimensions surface effects begin to dominate because of the large surface to volume ratio. Therefore, the surface interactions between feedstock and mold insert were studied. Finally, first observations of the injection molding experiments are shown and qualitatively compared to DPD simulation results.
• J Lienemann, A Greiner, JG Korvink
  Modeling, Simulation and Optimization of Electrowetting,
  2006 Ieee T Comput Aid D, volume: 25, issue: 2, pages: 234 - 247
  » show abstract« hide abstract
  Abstract

  Electrowetting is an elegant method to realize the motion, dispensing, splitting, and mixing of single droplets in a microfluidic system without the need for any mechanical—and fault-prone—components. By only applying an electric voltage, the interfacial energy of the fluid–solid interface is altered and the contact line of the droplet is changed. However, since the droplet shape is usually heavily distorted, it is difficult to estimate the droplet shape during the process. Further, it is often necessary to know if a process, e.g., droplet splitting on a given geometry, is possible at all, and what can be done to increase the system’s reliability. It is thus important to use computer simulations to gain an understanding about the behavior of a droplet for a given electrode geometry and voltage curve. Special care must be exercised when considering surface-tension effects. We present computer simulations done with the Surface Evolver program and a template library combined with a graphical user interface (GUI) that facilitates standard tasks in the simulation of electrowetting arrays.
• LH Feng, D Koziol, EB Rudnyi, JG Korvink
  Parametric model reduction for fast simulation of cyclic voltammograms,
  2006 Sens Lett, volume: 4, issue: 2, pages: 165 - 173
  » show abstract« hide abstract
  Abstract

  Model order reduction is a well-established technique for fast simulation of large-scale models based on ordinary differential equations, especially those in the field of integrated circuits and micro-electro-mechanical systems. In this paper, we propose the use of parametric model reduction for fast simulation of a cyclic voltammogram. Instead of being considered as a time varying system, the model for a cyclic voltammogram is treated as a system with a parameter (applied voltage) which is to be preserved during model reduction. Because voltage is preserved in the symbolic form during model reduction, we can simulate the cyclic voltammogram with a reduced system and therefore invest much less time and memory as compared with direct simulation based on the original large-scale model. We present our approach for a case study based on scanning electrochemical microscopy.
• L Riegger, M Grumann, T Nann, J Riegler, O Ehlert, W Bessler, K Mittenbühler, G Urban, L Pastewka, T Brenner, R Zengerle, J Ducrée
  Read-out concepts for multiplexed bead-based fluorescence immunoassays on centrifugal microfluidic platforms
  2006 Sensor Actuat A-phys, volume: 126, page: 455
• L Pastewka, D Kauzlaric, A Greiner, JG Korvink
  Thermostat with a local heat-bath coupling for exact energy conservation in dissipative particle dynamics,
  2006 Phys Rev E, volume: 76, page: 037701
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  Abstract

  We present a Markov process which models particle hydrodynamics with conservation of the first three momenta. This is achieved by extending the [Peters, Europhys. Lett. 66, 311 (2004)] and [Lowe, Europhys. Lett. 47, 145 (1999)] method to incorporate energy conservation. The equivalence of the energy conserving Peters method and dissipative particle dynamics with energy conservation (DPDE) in the limit of a vanishing time step is shown. Simple numerical experiments clearly demonstrate the applicability of the methods. This overcomes current limitations of DPDE in the study of complex fluids in the (N,V,E) ensemble.

2004

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• Varani L, Palermo C, Vaissiere J, Greiner A, L
  Avoiding spurious velocity overshoot in hydrodynamic simulation of deep submicron devices by a physical modeling of heat transport
  2004 Semiconductor Science and Technology, Vol. 19
• P Pomorski, L Pastewka, C Roland, H Guo, J Wang
  Capacitance, induced charges, and bound states of biased carbon nanotube systems
  2004 Phys Rev B, volume: 69, page: 115418

2001

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• JG Korvink, A Greiner, J Lienemann
  Numerical Offset Optimization of Magnetic Field Sensor Microsystems,
  2001 tm - Technisches Messen, volume: 68, issue: 6, page: 298
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  Abstract

  This paper rewievs the modeling of magnetic field sensor microsystems with respect to the origins of offsets. We cover the modeling of silicon-based semiconductor Hall sensors in an inhomogeneous magnetic field, including 3D transport effects. In particular we discuss the automatic geometric optimization of sensor devices. The optimization strategy achieves offset reduction with simultaneous maximazation of device sensitivity. The topology optimization method changes the conductivity of a Hall plate locally, converging to an optimum conduction geometry. After showing representative results, we discuss currently available commercial and experimental software tools and their capabilities. Dieser Artikel gibt einen Überblick über die Modellierung von Magnetfeld-Mikrosensoren hinsichtlich Offset. Wir diskutieren die automatische Offsetverminderung bei gleichzeitiger Maximalisierung der Empfindlichkeit. Nach Vorstellung repräsentativer Ergebnisse wird eine Liste kommerzieller und experimenteller Software und ihrer Fähigkeiten aufgestellt.

2000

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• Greiner Andreas, Reggiani Lino, Kuhn Tilmann, Varani L
  Carrier kinetics from the diffusive to the ballistic regime
  2000 Semicond Sci Tech, volume: 15, issue: 11, pages: 1071 - 1081

1999

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• Greiner A, Reggiani L, Kuhn T
  Transport coefficients for carriers with fractional exclusion statistics
  1999 Physica B, volume: 272, issue: 1-4, pages: 75 - 77

1998

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• Greiner A, Reggiani L, Vecchi MC, Kuhn T, Varani L, Golinelli P
  Carrier Thermal Conductivity: Analysis and Application to Submicron-Device Simulation
  1998 Vlsi Des, volume: 8, issue: 1-4, pages: 59 - 64
• Greiner A, Reggiani L, Kuhn T
  Comment on Quantized thermal conductance of dielectric quantum wires
  1998 Phys Rev Lett, volume: 81, issue: 22, pages: 5037 - 5037
• Greiner A, Vecchi M, Rudan M
  Modelling surface scattering effects in the Solution of the Boltzmann Transport Equation
  1998 Semicond. Sci. Technol. 13, volume: 13, issue: 10, pages: 1080 - 1089

1997

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• Greiner A, Reggiani L, Varani L, Kuhn T
  Thermal conductivity and Lorenz number for one-dimensional ballistic transport
  1997 Phys Rev Lett, volume: 78, issue: 6, pages: 1114 - 1117
• Greiner A, Varani L, Reggiani L, Kuhn T
  Dynamical Onsager coefficients in one-dimensional ballistic transport
  1997 Physica Status Solidi (b) 204

1996

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• Greiner A, Reggiani L, Varani L, Kuhn T
  Universal Thermal Conductance of Dielectric Quantum Wires
  1996 Nuovo Cimento D, volume: 18, issue: 12, pages: 1471 - 1473
• Greiner A, Reggiani L, Golinelli P, Varani L, Kuhn T
  Correlation Function Approach to Thermal Conductivity and Lorenz Number of Charge Carriers
  1996 Lithuanian Journal of Physics, volume: 36, pages: 542 - 549

1994

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• Hillmer H, Kuhn T, Greiner A, Hansmann S, Burkhard H
  The role of vertical transport and capture of electrons and holes for the transient optical response in quantum well heterostructures
  1994 Optical and Quantum Electronics 26, volume: 26, issue: 7, pages: S691 - S703

1992

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• Greiner A, Mahler G
  Phenomenological Field Theories for Layered Materials
  1992 Phys. Rev. B, volume: 46, pages: 7132 - 7143

Reviews

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2014

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• S Succi, N Moradi, A Greiner, S Melchionna
  Lattice Boltzmann modeling of water-like fluids
  2014 Frontiers in Physics, volume: 2, page: 22
  » show abstract« hide abstract
  Abstract

  We review recent advances on the mesoscopic modeling of water-like fluids, based on the lattice Boltzmann (LB) methodology. The main idea is to enrich the basic LB (hydro)-dynamics with angular degrees of freedom responding to suitable directional potentials between water-like molecules. The model is shown to reproduce some microscopic features of liquid water, such as an average number of hydrogen bonds per molecules (HBs) between 3 and 4, as well as a qualitatively correct statistics of the hydrogen bond angle as a function of the temperature. Future developments, based on the coupling the present water-like LB model with the dynamics of suspended bodies, such as biopolymers, may open new angles of attack to the simulation of complex biofluidic problems, such as protein folding and aggregation, and the motion of large biomolecules in complex cellular environments.
  
  
   
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Book reviews

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2016

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• L Pastewka
  Reibung unter Zugzwang
  2016 Physik Journal, volume: 15, issue: 3, pages: 16 - 17

Books

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2009

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• Der Andere Verlag
  Particle simulation of MEMS/NEMS components and processes - Theory, software design and applications
  D Kauzlaric

2002

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• Wiley-VCH
  Semiconductors for Micro- and Nanotechnology - An Introduction for Engineers An Introduction for Engineers,
  ISBN: 3-527-30257-3
  JG Korvink, A Greiner

Book chapters

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2019

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• L Pastewka, A Greiner
  HPC with Python: An MPI-parallel implementation of the Lattice Boltzmann Method
  In: Proceedings of the 5th bwHPC Symposium
  2019, Tübingen Library Publishing, pages: 101 - 118, ISBN: 978-3-946552-25-3
  » show abstract« hide abstract
  Abstract

  The Lattice Boltzmann Method is well suited for high-performance computational fluid dynamics. We show by means of a common two-dimensional test case, the lid-driven cavity problem, that excellent parallel scaling can be achieved in an implementation based on pure Python, using the numpy library and the Message Passing Interface. We highlight opportunities and pitfalls for the implementation of parallel high-performance codes in the high-level language Python.

2018

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• A Gola, L Pastewka
  Structure of Interfaces in Cu|Au Nanolaminates
  In: NIC Symposium 2018 - Proceedings
  2018, Forschungszentrum Jülich, pages: 247 - 254, ISBN: 978-3-95806-285-6
  » show abstract« hide abstract
  Abstract

  We used molecular dynamics calculations to study the influence of interdiffusion on the bicrystal interface of Cu|Au nanolaminates. Starting from an ideal bicrystal of 50 nm thickness with a {111} semi-coherent interface, we created a diffusive interface region and annealed the system at 1000K. We report the resulting interfacial crystallographic defects as a function of interface width. Our results show an increase of dislocation spacing as the interface becomes more diffuse. The most diffuse interfaces of ~10 nm width studied here form stacking fault tetrahedra.

2014

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• M Moseler, L Pastewka, J Hird
  Taming the untamable – The art and science of diamond polishing
  In: Comprehensive Hard Materials, Volume 3
  2014, Elsevier, VK Sarin, CE Nebel, pages: 81 - 98, VK Sarin, CE Nebel, ISBN: 978-0-08-096528-4

2012

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• L Pastewka, M Moseler
  The running-in of hydrogenated diamond-like carbon coatings
  In: NIC Symposium 2012 - Proceedings
  2012, Forschungszentrum Jülich, K Binder, M Münster, M Kremer, pages: 215 - 221, K Binder, M Münster, M Kremer, ISBN: 9783893367580

2009

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• D Kauzlaric, A Greiner, JG Korvink
  Process simulation with particle methods: micropowder injection moulding and hot embossing,
  In: Ceramics processing in microtechnology
  2009, Whittles Publishing, HJ Ritzhaupt-Kleissl, P Johander, pages: 34 - 43, HJ Ritzhaupt-Kleissl, P Johander,

2008

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• JG Korvink, A Greiner, Z Liu
  Multiphysics and Multiscale Simulation,
  In: Comprehensive Microsystems Volume 1
  2008, Elsevier, YB Gianchandani, O Tabata, H Zappe, pages: 539 - 557, YB Gianchandani, O Tabata, H Zappe,

2007

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• B Huber, L Pastewka, P Koskinen, M Moseler
  The Electronic Structures of Nanosystems: Calculating the Ground States of Sodium Nanoclusters and the Actuation of Carbon Nanotubes
  In: High Performance Computing in Science and Engineering ’06
  2007, Springer, WE Nagel, W Jäger, M Resch, pages: 59 - 67, WE Nagel, W Jäger, M Resch, ISBN: 978-3-540-36165-7

2006

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• J Lienemann, A Greiner, JG Korvink
  Modelling, Simulation and Optimization of Electrowetting
  In: Design Automation Methods and Tools for Microfluidics-Based Biochips
  2006, Springer, K Chakrabarty, J Zeng, pages: 53 - 84, K Chakrabarty, J Zeng,

2005

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• JG Korvink, EB Rudnyi, A Greiner, Z Liu
  MEMS and NEMS Simulation,
  In: MEMS: A Practical Guide to Design, Analysis, and Applications
  2005, Springer & William Andrew, JG Korvink, O Paul, pages: 93 - 186, JG Korvink, O Paul, ISBN: 978-3-540-21117-4
• D Kauzlaric, A Greiner, JG Korvink, M Schulz, R Heldele
  Modelling Micro-PIM,
  In: Microengineering of Metals and Ceramics, Part 1: Design, Tooling, and Injection Molding
  2005, Wiley-VCH, Baltes, Brand, Fedder, Hierold, Korvink, Tabata, pages: 51 - 84, Baltes, Brand, Fedder, Hierold, Korvink, Tabata, ISBN: 3-527-31208-0

2004

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• M Geier, A Greiner, D Kauzlaric, JG Korvink
  Nanofluidic Modeling and Simulation,
  In: Enabling Technologies for MEMS and Nanodevices
  2004, Wiley-VCH, H Baltes, O Brand, GK Fedder, C Hierold, JG Korvink, O Tabata, pages: 289 - 317, H Baltes, O Brand, GK Fedder, C Hierold, JG Korvink, O Tabata, ISBN: 978-3-527-30746-3

2003

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• J Lienemann, A Greiner, JG Korvink, X Xiong, Y Hanein, KF Böhringer
  Modelling, Simulation and Experimentation of a Promising New Packaging Technology - Parallel Fluidic Self-Assembly of Micro Devices,
  In: Sensors Update Volume 13
  2003, Wiley-VCH, pages: 3 - 43,

Conference papers

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2014

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• S Sharma, A Khalajhedayati, TJ Rupert, MJ Madou
  SU8 Derived Glassy Carbon for Lithium Ion Batteries,
  2014 Orlando, FL, USA 225th Electrochemical Society Meeting

2013

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• M Azhar, D Kauzlaric, A Greiner, JG Korvink
  Simulation of spin hydrodynamics using dissipative particle dynamics,
  2013 ECCOMAS Conference on Smart Structures and Materials, Torino, Italy
  » show abstract« hide abstract
  Abstract

  Meshless, particle based simulation approach like e.g, smoothed particle hydrodynamics (SPH) and dissipative particle dynamics (DPD) are well suited to address number of advanced application in many discipline like life science etc. DPD is a coarse grained technique that deals with mesoscopic models which lie in between microscopic dynamics and the local balance regime. On the other hand, NMR is a powerful technique which revealed the world of microscopic dimension. The purpose of this paper is to simulate spin dynamics using DPD technique.

2012

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• D Weiß, A Greiner, J Lienemann, JG Korvink
  Electrowetting droplets investigated with smoothed particle hydrodynamics and moving least squares,
  2012 7th IEEE NEMS 2012, Kyoto IEEE, pages: 304 - 307
  » show abstract« hide abstract
  Abstract

  The numerical analysis of oscillating electrowetting droplets is challenging predominantly due to the frequent change in topology of the phases involved and the coupling of electrostatic forces into the system. Damped systems require an even larger number of oscillations or simulation time steps, respectively, until resonance becomes apparent, and an efficient model is required.
• D Kauzlaric, O Liba, Y Hanein, P Espanol, A Greiner, S Succi, JG Korvink
  Top-down vs. bottom-up coarse-graining of graphene and CNTs for nanodevice simulation,
  2012 7th IEEE NEMS 2012, Kyoto IEEE, pages: 298 - 303

2011

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• E Bertarelli, R Ardito, A Greiner, JG Korvink, A Corigliano
  Design issues in electrostatic microplate actuators: device stability and post pull-in behaviour,
  2011 12th. Int. Conf. on Thermal, Mechanical and Multiphysics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2011 IEEE, pages: 1 - 6
  » show abstract« hide abstract
  Abstract

  In this work, electrostatic stability of microplate actuators is investigated. In particular, the possibility to improve device stability by adopting charge control is discussed. The parallel plate actuator is first introduced as case study. Then, a one degree-of freedom model is obtained for microplate electromechanics. The parasitic capacitance arising from the non-uniform device deformation is evaluated. This practically leads to a reduced capacitance feedback with respect to parallel plate systems. Consequently, a limited stabilizing effect of charge drive can be obtained. The analysis of microplate behaviour is completed by the evaluation of adhesion (stiction) when eventually pull-in is reached.

2009

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• E Bouendeu, A Greiner, PJ Smith, JG Korvink
  An efficient low cost electromagnetic vibration harvester,
  2009 Proc. PowerMEMS 2009, December 01-04, 2009, Washington D.C., USA , pages: 320 - 323
• J Lienemann, I Cenova, D Kauzlaric, A Greiner, JG Korvink
  Kopplung der Smoothed Particle Hydrodynamics-Methode mit einem Wärmetransportmodell reduzierter Ordnung für die schnelle Simulation des Mikrogussprozesses,
  2009 4. Kolloquium Mikroproduktion, pages: 99 - 104

2008

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• J Lienemann, I Cenova, D Kauzlaric, A Greiner, JG Korvink
  Coupling of Smoothed Particle Hydrodynamics and Reduced Order Heat Transfer Model for Casting Simulation,
  2008 Proceedings of the 5th International Conference of Applied Mathematics and Computing, FICAMC Proceedings of the 5th International Conference of Applied Mathematics and Computing, FICAMC, pages: 272 - 273

2007

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• M Geier, Z Liu, A Greiner, JG Korvink
  Cellular automaton based fluidic topology optimization,
  2007 Recent Developments in Structural Engineering, Mechanics and Computation, pages: 173 - 174
• A Kalms, M Salleras, Z Liu, JG Korvink, J Goebel, G Muller, J Samitier, S Marco
  Numerical Simulation of Ion Drift within Ion Mobility Spectrometers in High Peclet Conditions using FEM Techniques,
  2007 International Conference on Thermal, Mechanical and Multi-Physics Simulation Experiments in Microelectronics and Micro-Systems, 2007. EuroSime 2007. IEEE, pages: 1 - 6
  » show abstract« hide abstract
  Abstract

  The goal of this paper is to model and simulate the transport of ions through a miniaturised drift tube of ion mobility spectrometer (IMS). In the first part of this work we test and compare three numerical methods to solve the transient diffusion-advection equation in high Peclet conditions. These methods are the following: Streamline upwind Petrov Galerkin (SUPG), the modified-PDE (MPDE) and the finite calculus method (FIC). In the second part we use the last two numerical methods to study ion transport in a one-dimensional IMS model. Ion peak broadening effects, namely coulombic repulsion, diffusion, transport of two ionic species, have been explored for different initial conditions.
• O Levy, Y Hanein, D Kauzlaric, A Greiner, JG Korvink
  Reduced molecular model for the mechanics of carbon nanotubes,
  2007 Proceedings of the APCOM07, page: 357
• D Kauzlaric, L Pastewka, C Bretthauer, A Greiner, JG Korvink
  SPH simulation of the embossing and injection moulding of micro-parts: Softening and aggregation aspects,
  2007 Proceedings of the 3rd International Conference on Multi-Material Micro Manufacture, 4M 2007
• D Kauzlaric, L Pastewka, C Bretthauer, A Greiner, JG Korvink
  Simulation of the micro-structuring of polymeric materials with particle methods,
  2007 Proceedings of the 3rd International Conference on Structural Engineering, Mechanics and Computation, SEMC 2007, page: 191

2006

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• L Del Tin, R Gaddi, A Gnudi, EB Rudnyi, A Greiner, JG Korvink
  Efficient pre-stressed harmonic analysis of RF-microresonators by means of model order reduction,
  2006 7th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems, 2006. EuroSime 2006. EuroSimE 2006, Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems, 24-26 April, IEEE, pages: 1 - 4
  » show abstract« hide abstract
  Abstract

  A simulation methodology to reduce computational time of pre-stressed harmonic analysis of radio frequency (RF) microresonators is demonstrated. The methodology is based on the application of model order reduction to a system of ordinary differential equations obtained after spatial discretization by finite element software. Model order reduction produces a low dimensional approximation of the original system and hence enables a substantial reduction of simulation time while maintaining a very small approximation error. The approach allows performing rapid device design and optimization. Once the device design and working conditions have been defined its reduced model can also be used to implement a behavioural model that can be employed in system level simulations.
• JG Korvink, EB Rudnyi, Z Liu, A Greiner
  New Techniques for the Simulation of Microanalytical Instrumentation,
  2006 Pittcon 2006, 57th Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, March 12-17, Symposia - Smaller, Cheaper, Faster and Smarter Analytical Instrumentation
• EB Rudnyi, C Moosmann, A Greiner, T Bechtold, JG Korvink
  Parameter Preserving Model Reduction for MEMS System-level Simulation and Design,
  2006 MATHMOD 2006, February 8 - 10, Vienna University of Technology, Vienna, Austria
• C Bretthauer, D Kauzlaric, A Greiner, JG Korvink
  Particle based modeling of ultrasonic plastification with a yield-stress fluid,
  2006 Proceedings of the 3rd International Conference on Multiscale Materials Modeling, MMM 2006, September 18-22, 2006, Freiburg, Germany , pages: 917 - 920

2005

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• J Lienemann, A Greiner, JG Korvink
  Beam Actuated by Electrostatic Force,
  2005 Oberwolfach Model Reduction Benchmark Collection, Oberwolfach
• R Heldele, M Schulz, D Kauzlaric, JG Korvink, J Hausselt
  Micro Powder Injection Molding - Process Characterization and Modeling,
  2005 DTIP 2005
• D Kauzlaric, L Pastewka, A Greiner, JG Korvink
  MikroPIM, Füllsimulation mit Partikeldynamischen Methoden,
  2005 Tagungsband des Kolloquium Mikroproduktion, Aachen , pages: 151 - 165
• M Grumann, L Riegger, T Nann, J Riegler, O Ehlert, K Mittenbühler, G Urban, L Pastewka, T Brenner, R Zengerle, J Ducrée
  Parallelization of chip-based fluarescence immuno-assays with quantum-dot labeled beads
  2005 Proc Transducers, pages: 1114 - 1117
• C Moosmann, EB Rudnyi, A Greiner, JG Korvink, M Hornung
  Parameter preserving Model Order Reduction of a Flow Meter,
  2005 Technical Proceedings of the 2005 Nanotechnology Conference and Trade Show, Nanotech 2005, May 8-12, NSTI-Nanotech, vol. 3

2004

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• J Lienemann, A Greiner, EB Rudnyi, JG Korvink, L Ferrario, M Zen
  Automatic order reduction for finite element models,
  2004 Books of abstracts of the 9th National conference on Sensor and Microsystems - AISEM 2004, February 8-11, Ferrara, Italy , pages: 411 - 417
• JG Korvink, A Greiner, EB Rudnyi
  Computational Mechanics in MEMS: From Spanning the Scales to Order Reduction,
  2004 International Workshop on Advances in Computational Mechanics (IWACOM) November 3-6, 2004, Hosei University, Tokyo, Japan , pages: 151 - 151
• M Geier, A Greiner, JG Korvink
  Galilean Invariant Viscosity Term for an Athermal Integer Lattice Boltzmann Automaton in three Dimensions,
  2004 Technical Proceedings of the 2004 NSTI Nanotechnology Conference and Trade Show, Volume 1, pages: 255 - 258
• J Lienemann, D Billger, EB Rudnyi, A Greiner, JG Korvink
  MEMS Compact Modeling Meets Model Order Reduction: Examples of the Application of Arnoldi Methods for Microsystem Devices,
  2004 Technical Proceedings of the 2004 Nanotechnology Conference and Trade Show, Nanotech 2004, March 7-11, Bosten, Massachusetts , volume: 2, pages: 303 - 306
• C Moosmann, EB Rudnyi, A Greiner, JG Korvink
  Model Order Reduction for Linear Convective Thermal Flow,
  2004 THERMINIC 2004, 10th International Workshop on Thermal Investigations of ICs and Systems, 29 September - 1 October 2004
• D Kauzlaric, A Greiner, JG Korvink
  Modelling Micro-Rheological Effects in Micro Injection Moulding with Dissipative Particle Dynamics,
  2004 Technical Proceedings of the 2004 Nanotechnology Conference and Trade Show Vol. 2, Boston, MA, USA , pages: 454 - 457
• P Pomorski, L Pastewka, C Roland, H Guo, J Wang
  Quantum simulations of carbon nanotube charging and capacitance
  2004 Mat Res Soc Symp Proc, page: N3.6.1
• EB Rudnyi, J Lienemann, A Greiner, JG Korvink
  mor4ansys: Generating Compact Models Directly from ANSYS Models,
  2004 Technical Proceedings of the 2004 Nanotechnology Conference and Trade Show, Nanotech 2004, March 7-11, Bosten, Massachusetts, USA , volume: 2, pages: 279 - 282

2003

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• Greiner A, Varani L, Palermo C, Vaissiere J, L
  Heat transport and spurious velocity overshoots in moment-based simulations of deep-submicron devices
  2003 Proceedings of the 14th Workshop on Modelling and Simulation of Electron Devices
• M Geier, A Greiner, JG Korvink
  An Unconditionally Stable Integer Lattice Boltzmann Method for Multi-Scale Simulations of Polymeric Solutions,
  2003 Conference Proceedings Polytronic 2003, Montreux, Switzerland , pages: 315 - 320
• D Kauzlaric, A Greiner, JG Korvink
  An alternative simulation method for micro injection moulding,
  2003 Conference Proceedings Polytronic 2003, Montreux, Switzerland , pages: 79 - 85
• J Lienemann, A Greiner, JG Korvink
  Electrode Shapes for Electrowetting Arrays,
  2003 Technical Proceedings of the 2003 Nanotechnology Conference and Trade Show Vol. 1, San Francisco, CA, USA , pages: 94 - 97
• D Kauzlaric, A Greiner, JG Korvink
  Modelling of microrheological behaviour of fluids with Dissipative Particle Dynamics,
  2003 VDI Berichte 1803 , pages: 179 - 182

2002

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• A Greiner, J Lienemann, JG Korvink, X Xiong, Y Hanein, KF Boehringer
  Capillary Forces in Micro-Fluidic Self-Assembly,
  2002 Technical Proceedings of the MSM2002, Puerto Rico , pages: 198 - 201
• D Koziol, J Ufheil, A Greiner, J Heinze, JG Korvink
  Simulation of Multi-Disc Ultra Micro-Electrodes for the Scanning Electrochemical Microscope,
  2002 IMCS9, Boston, USA
• J Lienemann, A Greiner, JG Korvink
  Surface Tension Defects in Micro-Fluidic Self-Alignment,
  2002 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS DTIP 2002, Cannes-Mandelieu, France , pages: 55 - 63
• J Lienemann, A Greiner, JG Korvink
  Volume shrinking in Micro-Fluidic Self-Assembly,
  2002 The Fourth International Conference on Advanced Semiconductor Devices and Microsystems, 2002. IEEE, pages: 369 - 372
  » show abstract« hide abstract
  Abstract

  Self assembly in the fluidic phase is a technique excellently suited for the parallel assembly of millions of micro-parts, as it is necessary for pixel displays. In this work, we investigate the effect of volume shrinking during an inhomogeneous polymerization of the glue and discuss the implications for the design of the assembled micro-parts.

2001

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• J Lienemann, A Greiner, JG Korvink, O Sigmund
  Optimization of Integrated Magnetic Field Sensors,
  2001 Hilton Head Technical Proceedings of the MSM 2001 4th International Conference on Modeling and Simulation of Microsystems, pages: 120 - 123

1999

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• A Greiner, JG Korvink
  Analysis of Noise and Fluctuations in Micromachined Devices,
  1999 Invited paper, Proc. SPIE Conf. on Micromachined Devices and Components, Santa Clara CA, USA SPIE, volume: 3867, pages: 104 - 112
• A Greiner, JG Korvink
  Fluctuating Mode Amplitudes of the Electronic Nose,
  1999 Proc. MSM 99, Puerto Rico, USA , pages: 617 - 619

1998

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• Reggiani S, Vecchi M, Greiner A, Rudan M
  Modelling hole surface and bulk mobility in the frame of a spherical harmonics solution of the Boltzmann transport equation,
  1998 Proc. of SISPAD?98, Edts. K. De Meyer, S. Biesemans
• A Greiner, JG Korvink
  Extraction of Noise Parameters for the Macromodeling of MEMS,
  1998 Second International Conference on Advanced Semiconductor Devices and Microsystems, 1998. ASDAM '98. ASDAM?98, IEEE, page: 311
  » show abstract« hide abstract
  Abstract

  We investigate mechanical noise sources of micromechanical systems. The description of noise in the framework of a correlation function formulation is presented and the influence of different operating conditions on the description of a micromachined cantilever as an example is explained. It turns out that the most interesting operation regime will be found where several different timescales occur due so the reduction of a single dominant dissipation channel which in this case is formed by the molecular motion of the gas as an environmental the cantilever. We expect this transition regime to be governed by several diffraction time-scales of comparable magnitude due to the interaction of the learning degree of freedom.

1997

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• Greiner A, Reggiani L, Kuhn T, and
  Kinetic coefficients in one-dimensional quantum transport,
  1997 INFM-Congress, Chia, Sardegna, Italy, May 19-23
• Vecchi M, Pierantoni A, Greiner A, and
  Modelling of surface-scattering mechanisms and soft-threshold impact-ionization in the analysis of realistic MOS devices,
  1997 191st Meetinf of the ELECTROCHEMICAL SOCIETY - Montreal, Quebec, Canada

1996

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• Reggiani L, Golinelli P, Greiner A, Pennetta C, Gruzhinskis V, Starikov E, Shitkorov P, Varani L, Vaissiere J, Nougier J, Pardo D, Gonzalez T, Martin M
  Advances in noise modelling of high-field transport in semiconductor materials and structures
  1996 Proceedings of the 3rd ELEN Workshop, 05-07 Nov. 1996, Leuven, Belgium
• Hillmer H, Greiner A, Steinhagen F, Burkhard H, Lösch R, Schlapp W, and
  Carrier and Photon Dynamics in transversally asymmetric high-speed AlGaInAs/InP MQW Laser
  1996 SPIE Proceedings, Vol. 2693-41
• Vecchi M, Greiner A, and
  Modeling surface scattering effects in the solution of the BTE based on spherical harmonics expansion,
  1996 Proceedings of the ESSDERC?96

1995

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• Hillmer H, Greiner A, Steinhagen F, Lösch R, Schlapp W, Binder E, Kuhn T, and
  Carrier and Photon Dynamics in InAlGaAs/InP MQW Laser Structures,
  1995 Proceedings of the HCIS, Chicago
• Greiner A, Kuhn T, Hillmer H, Hansmann S, H
  Carrier transport in quantum well lasers,
  1995 Quantum Transport in Ultrasmall Devices, Edts. David K. Ferry and Harold L. Grubin and Carlo Jacoboni and Anti-Pekka Jauho

1994

 back to the year overview

• Greiner A, Kuhn T, Hillmer H, Hansmann S, and
  Influence of carrier transport on the turn?on delay in a separate confinement heterostructure quantum well laser
  1994 Technical Digest of the Conference on Lasers and Electro?Optics Europe, Amsterdam, The Netherlands, 28 August - 2 September

1989

 back to the year overview

• Greiner A, Mahler G, Kriman A, and
  Generalized Continuum Approach to Phonon Modes in Heterojunctions
  1989 Proceedings of the Third International Conference on Phonon Physics and the Sixth International Conference on Phonon Scattering in Condensed Matter, Edts. S. Hunklinger and W. Ludwig and G. Weiss