A5038696193- Magnetic properties of thin films
- Advanced Chemical Physics Studies
- Physics of Superconductivity and Magnetism
- Adhesion, Friction, and Surface Interactions
- Force Microscopy Techniques and Applications
- Quantum and electron transport phenomena
- Rare-earth and actinide compounds
- Magnetic Properties of Alloys
- Surface and Thin Film Phenomena
- Metal and Thin Film Mechanics
- Surface Roughness and Optical Measurements
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- Lubricants and Their Additives
- Diamond and Carbon-based Materials Research
- Magnetic and transport properties of perovskites and related materials
- Magneto-Optical Properties and Applications
- Molecular Junctions and Nanostructures
- Chemical and Physical Properties of Materials
- Advanced Physical and Chemical Molecular Interactions
- Advanced Measurement and Metrology Techniques
- Advanced Surface Polishing Techniques
- Electron and X-Ray Spectroscopy Techniques
- Mechanical stress and fatigue analysis
- Semiconductor materials and interfaces
AC2T Research (Austria)
2014-2025
TU Wien
2012-2024
Technical University of Cluj-Napoca
2021
University of Applied Sciences Technikum Wien
2010-2012
Austrian Academy of Sciences
2008
University of Vienna
2001-2006
Budapest University of Technology and Economics
2001
Ludwig-Maximilians-Universität München
1996-2000
Goethe University Frankfurt
1997
Institut für Urheber- und Medienrecht
1997
We performed molecular dynamics simulations of boundary-lubricated sliding, varying the boundary lubricant type, its surface coverage, substrate roughness, and load. The resulting load versus friction behavior was then analyzed to study how changes in roughness affect extrapolated force at zero load, so-called Derjaguin offset. A smooth-particle-based evaluation method by authors, applied here for first time visualize sliding interface between two layers lubricant, allowed definition...
Using molecular dynamics, we simulate the abrasion process of an atomically rough Fe surface with multiple hard abrasive particles. By quantifying nanoscopic wear depth in a time-resolved fashion, show that Barwell's macroscopic law can be applied at atomic scale. We find this multiasperity contact system, Bowden-Tabor term, which describes friction force as function real area, predict kinetic even when is involved. From Derjaguin-Amontons-Coulomb recovered, since observe linear dependence...
van der Waals (vdW) forces play a fundamental role in the structure and behavior of diverse systems. Because development functionals that include nonlocal correlation, it is possible to study effects vdW interactions systems industrial tribological interest. Here we simulated within framework density functional theory (DFT) adsorption isooctane (2,2,4-trimethylpentane) ethanol on an Fe(100) surface, employing various exchange-correlation take into account. In particular, this paper discusses...
The Microporous Layer (MPL) plays a crucial role in Proton Exchange Membrane Fuel Cells (PEMFCs), as its microstructure significantly influences the overall transport properties within these devices. This study introduces novel Machine Learning (ML) approach to optimize MPL and properties. Synthetic datasets were generated by considering key manufacturing parameters, including carbon particle diameter, Solid Volume Percentage (SVP), polytetrafluoroethylene (PTFE) SVP, used calculate output...
The electronic structures of the skutterudite-type phosphides ${\mathrm{CoP}}_{3}$ and ${\mathrm{NiP}}_{3}$ have been investigated by means first-principles linear muffin-tin orbital--atomic sphere approximation band-structure calculations. presence ${\mathrm{P}}_{4}$ rings in skutterudite structure is great importance determining nature bands around Fermi level, composed mainly \ensuremath{\pi}-type molecular orbitals these units. metallic character found for should be ascribed to...
A scheme is presented that allows us to manipulate the spin-orbit coupling in calculations based on Dirac equation for spin-dependent potentials. To demonstrate its application, spin and orbital magnetic moments disordered alloy ${\mathrm{Fe}}_{0.20}$${\mathrm{Ni}}_{0.80}$ as well Kerr rotation angle ${\mathrm{\ensuremath{\theta}}}_{\mathit{K}}$ of pure Ni have been calculated a function strength. While moment changes only slightly, increase almost linearly with \textcopyright{} 1996 The...
A series of density functional theory (DFT) simulations was performed to investigate the approach, contact, and subsequent separation two atomically flat surfaces consisting different materials. Aluminum (Al) titanium nitride (TiN) slabs were chosen as a model system representing metal-ceramic interface interaction between soft hard The approach simulated by moving one slab in discrete steps normal allowing for electronic atomic relaxations after each step. Various configurations analyzed...
It is shown that a useful relativistic generalization of the conventional spin density $\stackrel{P\vec}{s}(\stackrel{P\vec}{r},t)$ for case moving electrons expectation value $\mathbf{(}\stackrel{P\vec}{\mathcal{T}}(\stackrel{P\vec}{r},t),{\mathcal{T}}_{4}(\stackrel{P\vec}{r},t)\mathbf{)}$ four-component Bargmann-Wigner polarization operator ${T}_{\ensuremath{\mu}}=(\stackrel{P\vec}{T},{T}_{4})$ [Proc. Natl. Acad. Sci. U.S.A. 34, 211 (1948)] with respect to four components wave function. An...
A post-processing method for molecular dynamics (MD) simulations of friction based on the smooth particle approach is proposed, allowing--among other features--the introduction and evaluation a solid-solid contact area arising due to direct asperity interaction. In order illustrate feasibility this scheme, large number MD calculations lubricated nanotribological systems with various geometries carefully selected numbers lubricant molecules were carried out analysed. manner, it shown that...
While there are a number of models that tackle the problem calculating friction forces on atomic level, providing completely parameter-free approach remains challenge. Here we present quasi-static model to obtain an approximation nanofrictional response dry, wearless systems based quantum mechanical all-electron calculations. We propose mechanism allow dissipative sliding, which relies relaxations. define two different ways mean nanofriction force, both leading exponential...
The surface quality of high gloss polished steel sheets with respect to ‘orange peel’ is studied. This motivated by the fact that workpieces are ranked solely on visual appearance finished surfaces according observed degree orange peel. Here, quantify peel, topographies industrial samples acquired means phase shifting interferometry, from which various roughness parameters calculated. These related qualitative aspects using Spearman's rank correlation coefficient. Two were identified as...
In this work we perform molecular dynamics simulations to quantify and parametrize the evolution of a bcc Fe piece topography during nanometric grinding with multiple hard abrasive particles. The final surface quality depends on both normal pressure geometry. We fit time development substrate's root mean squared roughness an exponential function, allowing definition run-in regime, which 'forgets' about its initial state, steady-state regime where no longer changes. constants associated...
A novel formulation of elastic multi-asperity contacts based on the boundary element method (BEM) is presented for first time, in which influence coefficients are numerically calculated using a finite (FEM). The main advantage computing this manner that it makes also possible to consider an arbitrary load direction and multilayer systems different mechanical properties each layer. Furthermore, any form anisotropy can be modelled too, where Green's functions either become very complicated or...
The resistivities of the ferromagnetic alloy systems Fe-Ni and Co-Ni were studied in detail by application first-principles techniques. For that purpose Kubo-Greenwood formalism was applied on basis electronic structure data obtained using spin-polarized Korringa-Kohn-Rostoker coherent potential approximation method band-structure calculation for randomly disordered alloys. One set calculations carried out fully relativistically, while a second one well-known often two-current model used. We...
The presence of water in biofuels poses the question how it affects frictional performance additives fuels containing organic substances. To investigate effect on adsorption molecules present fuel and its we simulated within framework density functional theory ethanol, isooctane (2,2,4-trimethylpentane), acetic acid a bare water-covered Fe(100) surface. Van der Waals interactions are taken into account our computations. In those molecules, where dispersion forces contribute significantly to...
First-principles calculations of the electrical conductivity disordered ferromagnetic alloys based on Kubo-Greenwood formalism and spin-polarized relativistic Korringa-Kohn-Rostoker coherent-potential-approximations method are presented. Application to alloy systems Co-Pd Co-Pt yields results for isotropic anisotropic residual resistivity which in very satisfying agreement with experiment. In addition, scalar-relativistic were performed basis two-current model these systems, found agree...
A post-processing method, which maps the punctiform atoms in molecular dynamics (MD) simulations of boundary lubrication onto smoothed particles, is used to estimate asperity contact area defined by minimum cross-section formed solid bridges. It then shown that this excellently agrees with projected resulting from a Voronoi tessellation corresponding zone, and it can be applied compute constitutive system parameters three-term friction law, found hold for any boundary-lubricated...
Motivated by the unexpectedly strong influence of Te atoms on structural and bonding properties transition metal tellurides, we have performed a detailed study . Experimentally, this comprises crystal structure determination as well electrical resistivity measurements. The former analysis leads to an accurate update data reported in 1960s, while latter provides evidence for mainly electronic character scattering processes leading conductivity. In addition, been calculated using TB-LMTO...